SAITO NAOKI (JP)
YOKOYAMA HIROSHI (JP)
KATAYAMA AKIO (JP)
SAITO NAOKI (JP)
YOKOYAMA HIROSHI (JP)
| JP2002328215A | 2002-11-15 | |||
| JP2004091560A | 2004-03-25 | |||
| JP2005181383A | 2005-07-07 | |||
| JP2004211095A | 2004-07-29 | |||
| JP2002194244A | 2002-07-10 | |||
| JP2003336001A | 2003-11-28 |
CLAIMS
1. A color filter having a layer colored in at least one prescribed hue and formed on a substrate, which comprises: a water-insoluble organic pigment (a), a monomer or oligomer having a polymerizable group (b), and a water-soluble polymer (c), in the form of a pigment dispersion, in which the dispersion is solidified by polymerizing the monomer or oligomer so as to form said colored layer, wherein a content of the water-soluble polymer (c) in the colored layer is at least 0.1 mass % of the total solid content.
2. The color filter as claimed in claim 1, wherein the pigment dispersion comprises the organic pigment (a) in a form of fine particles, wherein the fine particles are deposited by mixing an organic pigment solution of the organic pigment (a) dissolved in a good solvent, together with a solvent that has compatibility with the good solvent and functions as a poor solvent for the organic pigment.
3. The color filter as claimed in claim 2, wherein a number-average particle diameter of the pigment fine particles is in a range of from 0.005 μm to 1 μm.
4. The color filter as claimed in claim 2, wherein a number-average particle diameter of the pigment fine particles is in a range of from 0.005 μm to 0.08 μm.
5. The color filter as claimed in claim 2, wherein a number-average particle diameter of the pigment fine particles is in a range of from 0.005 μm to 0.05 μm. 6. The color filter as claimed in any one of claims 1 to 5, wherein a number-average molecular weight of the water-soluble polymer is 1,000 or more.
7. A liquid crystal display device installed with the color filter as claimed in any one of claims 1 to 6.
8. A CCD device installed with the color filter as claimed in any one of claims 1 to 6.
9. A pigment dispersion, which comprises a water-insoluble organic pigment (a) and a water- soluble polymer (b), wherein a water content of the pigment dispersion is 10 mass% or less, and wherein a content of the water-soluble polymer (b) is at least 0.1 mass% of the organic pigment (a).
10. The pigment dispersion as claimed in claim 9, which comprises the organic pigment (a) in a form of fine particles, wherein the fine particles are deposited by mixing an organic pigment solution of the organic pigment (a) dissolved in a good solvent, together with a solvent that has compatibility with the good solvent and functions as a poor solvent for the organic pigment.
1 1. The pigment dispersion as claimed in claim 10, wherein a number-average particle diameter of the pigment fine particles is in a range of from 0.005 μm to 1 μm.
12. The pigment dispersion as claimed in claim 10, wherein a number-average particle diameter of the pigment fine particles is in a range of from 0.005 μm to 0.08 μm.
13. The pigment dispersion as claimed in claim 10, wherein a number-average particle diameter of the pigment fine particles is in a range of from 0.005 μm to 0.05 μm.
14. The pigment dispersion as claimed in any one of claims 9 to 13, wherein a number-average molecular weight of the water-soluble polymer is 1,000 or more. |
DESCRIPTION
COLOR FILTER, AND LIQUID CRYSTAL DISPLAY DEVICE AND CCD DEVICE EACH USING
THE COLOR FILTER
TECHNICAL FIELD
[0001]
The present invention relates to a color filter having a high contrast ratio and an excellent hue, and to a liquid crystal display device and a CCD device each using the color filter.
BACKGROUND ART
[0002]
Recently, in accordance with improvements in image quality of liquid crystal display devices
(LCD), employment of the LCD in place of the CRT (Braun tube) that is a popularized display is progressing in a wide variety of end uses. Accordingly, there is a demand for products that exhibit much higher quality image display performances in terms of a color reproduction range and brightness.
Improvement in performances of the color filter is a key to responding to such the demand. This is because the color filter plays a role in coloring of display image of a LCD panel and the like, and therefore directly controls color properties of the LCD panel. As properties required for the color filter, high optical transmission, color purity, high contrast, lowered reflection, and the like can be mentioned. In particular, a low contrast causes a display screen to become dark owing to attenuation of light and causes discrimination between dark and bright to become unclear. Therefore, a high contrast property is desired. Besides, it is also desired that a reproduction range of color that is obtained by combining B, G, and R is wide, and purity of each of thus-obtained color is high. However, improvement of contrast of color filters sometimes results in decrease in color purity accompanied by a decrease of a color reproduction range.
[0003]
Ordinarily, in a method for production of color filter, use has been made of a technique of forming a colored layer by using a dispersion in which a coloring matter is dispersed in an organic solvent (JP-A- 10- 130547 ("JP-A" means unexamined published Japanese patent application), JP-A-10-148712, and
JP-A-2000-239554). This technique is common to all color-filter production methods by coating, printing
(transfer), and inkjet. Therefore, as a polymer that is primarily used as a dispersing agent or a binder, materials having high dispersibility in an organic system have been used. On account that moisture absorption by color filter or the like factor impairs reliability, there is almost no report of the technology of incorporating a polymer having a high water-solubility in a colored layer, except for some rarely used methods such as staining.
DISCLOSURE OF INVENTION [0004] The problem to be solved in the present invention is to provide a color filter that has a high contrast and an excellent chromaticity and also has suitability for a continuous production. Further, another problem to be solved in the present invention is to provide a liquid crystal display device and a
CCD device each exhibits excellent image display performances, in which the above-described high quality color filter is used.
[0005]
The objects of the present invention have been attained by the following means: (I) A color filter having a layer colored in at least one prescribed hue and formed on a substrate, which comprises: a water-insoluble organic pigment (a), a monomer or oligomer having a polymerizable group (b), and a water-soluble polymer (c), in the form of a pigment dispersion, in which the dispersion is solidified by polymerizing the monomer or oligomer so as to form said colored layer, wherein a content of the water-soluble polymer (c) in the colored layer is at least 0.1 mass % of the total solid content.
(2) The color filter as described in (1), wherein the pigment dispersion comprises the organic pigment (a) in a form of fine particles, wherein the fine particles are deposited by mixing an organic pigment solution of the organic pigment (a) dissolved in a good solvent, together with a solvent that has compatibility with the good solvent and functions as a poor solvent for the organic pigment. [0006]
(3) The color filter as described in (2), wherein a number-average particle diameter of the pigment fine particles is in a range of from 0.005 μm to 1 μm.
(4) The color filter as described in (2), wherein a number-average particle diameter of the pigment fine particles is in a range of from 0.005 μm to 0.08 μm.
(5) The color filter as described in (2), wherein a number-average particle diameter of the pigment fine particles is in a range of from 0.005 μm to 0.05 μm.
(6) The color filter as described in any one of (1) to (5), wherein a number-average molecular weight of the water-soluble polymer is 1,000 or more. (7) A liquid crystal display device installed with the color filter as described in any one of (1) to
(6).
(8) A CCD device installed with the color filter as described in any one of (1) to (6). [0007]
(9) A pigment dispersion, which comprises a water-insoluble organic pigment (a) and a water- soluble polymer (b), wherein a water content of the pigment dispersion is 10 mass% or less, and wherein a content of the water-soluble polymer (b) is at least 0.1 mass% of the organic pigment (a).
(10) The pigment dispersion as described in (9), which comprises the organic pigment (a) in a form of fine particles, wherein the fine particles are deposited by mixing an organic pigment solution of the organic pigment (a) dissolved in a good solvent, together with a solvent that has compatibility with the good solvent and functions as a poor solvent for the organic pigment.
(1 1) The pigment dispersion as described in (10), wherein a number-average particle diameter of the pigment fine particles is in a range of from 0.005 μm to 1 μm. (12) The pigment dispersion as described in (10), wherein a number-average particle diameter of the pigment fine particles is in a range of from 0.005 μm to 0.08 μm.
(13) The pigment dispersion as described in (10), wherein a number-average particle diameter of
the pigment fine particles is in a range of from 0.005 μm to 0.05 μm.
(14) The pigment dispersion as described in any one of (9) to (13), wherein a number-average molecular weight of the water-soluble polymer is 1,000 or more.
Other and further features and advantages of the invention will appear more fully from the following description.
BEST MODE FOR CARRYING OUT THE INVENTION [0008]
Hereinafter, the present invention will be described in detail. The color filter of the present invention has at least one colored layer formed on a substrate. As the substrate, a transparent substrate is preferred, and use can be made of glass plates such as a soda glass plate having a silicon oxide coating on a surface thereof, a low-expansion glass, and a silica glass plate. Alternatively, resin films such as polyethylene terephtharate, cellulose triacetate, polystyrene, and polycarbonate may be used. [0009]
As a method of forming the colored layer on the substrate, there is no particular limitation, so long as it is an ordinary method used to prepare a color filter. As described later, a color filter may be obtained by coating such pigment dispersion as described later on a substrate, to form a colored photosensitive resin layer using an apparatus such as a spin coater, a slit coater, and a roll coater, followed by exposure and development. Besides, it is also preferred to use a method in which a colored layer is formed by initially forming the above-described colored photosensitive resin layer on a temporary support, and then transferring the colored photosensitive resin layer on a substrate using a laminator, followed by exposure and development; and/or a method in which a colored layer is formed by spraying drops of a pigment dispersion onto a substrate using a so-called inkjet system. The thickness of the colored layer is not particularly limited, but preferably in the range of from 0.5 μm to 5 μm, and more preferably in the range of from 1 μm to 3 μm. The area of the colored layer is not particularly limited. But, when fine pixels are formed, the area is preferably in the range of from 400 μm 2 to 90,000 μm 2 , and more preferably in the range of from 1,000 μm 2 to 15,000 μm 2 . [0010] The above-described colored layer in the color filter of the present invention is formed from a polymerized and solidified material that is obtained by polymerizing a pigment dispersion comprising a water-insoluble organic pigment (a), a monomer or oligomer having a polymerizable group (b), and a water-soluble polymer (c). Here, it is preferred to incorporate a binder (d) and a polymerization initiator or polymerization initiator series (e). [0011]
(a) Water-insoluble organic pigment
As the water-insoluble organic pigment, there is no particular limitation, so long as the pigment is sparingly soluble in water. It is preferred that the pigment is dispersed in a dispersion in a form of fine pigment particles. When fining the pigment, a preferable method may be chosen from various methods such as a vapor phase method, a grinding method, a re-precipitation method, and a laser ablation method, according to the kind of pigment and/or purpose. It is preferred to use such a fine particle deposition method which will be described later, from the viewpoint of obtaining pigment particles that are fine in size
and have a uniform particle size distribution and excellent dispersion stability. [0012]
Specifically, examples the water-insoluble organic pigment include perylene-, perynone-, quinacridone-, quinacridonequinone-, anthraquinone-, anthanthrone-, benzimidazolone-, condensed disazo-, disazo-, azo-, indanthrone-, p ' hthalocyanine-, triaryl carbonium-, dioxazine-, aminoanthraquinone-, diketopyrrolopyrrole-, thioindigo-, isoindoline-, isoindolinone-, pyranthrone-, or isoviolanthrone-compound pigment, or a mixture thereof.
[0013]
More specifically, examples of the water-insoluble organic pigment include perylene-compound pigments, such as C.I. Pigment Red 190 (CI. No. 71140), C.I. Pigment Red 224 (CI. No. 71 127), C.I. Pigment Violet 29 (CI. No. 71 129), or the like; perynone-compound pigments, such as C.I. Pigment Orange 43 (CI. No. 71105), C.I. Pigment Red 194 (CI. No. 71 100) or the like; quinacridone-compound pigments, such as C.I. Pigment Violet 19 (CI. No. 73900), C.I. Pigment Violet 42, CI. Pigment Red 122 (CI. No. 73915), C.I. Pigment Red 192, C.I. Pigment Red 202 (CI. No. 73907), CI. Pigment Red 207 (CI. Nos. 73900, 73906), CI. Pigment Red 209 (CI. No. 73905) or the like; quinacridonequinone-compound pigments, such as C.I. Pigment Red 206 (CI. No. 73900/73920), C.I. Pigment Orange 48 (CI. No. 73900/73920), C.I. Pigment Orange 49 (CI. No. 73900/73920), or the like; anthraquinone-compound pigments, such as C.I. Pigment Yellow 147 (CI. No. 60645) or the like; anthanthrone-compound pigments, such as C.I. Pigment Red 168 (CI. No. 59300) or the like; benzimidazolone-compound pigments, such as C.I. Pigment Brown 25 (CI. No. 12510), CI. Pigment Violet 32 (CI. No. 12517), C.I. Pigment Yellow 180 (CI. No. 21290), C.I. Pigment Yellow 181 (CI. No. 11777), C.I. Pigment Orange 62 (CI. No. 11775), C.I. Pigment Red 185 (CI. No. 12516), or the like; condensed disazo-compound pigments, such as C.I. Pigment Yellow 93 (CI. No. 20710), C.I. Pigment Yellow 94 (CI. No. 20038), C.I. Pigment Yellow 95 (CI. No. 20034), C.I. Pigment Yellow 128 (CI. No. 20037), C.I. Pigment Yellow 166 (CI. No. 20035), C.I. Pigment Orange 34 (CI. No. 21115), C.I. Pigment Orange 13 (CI. No. 21110), C.I. Pigment Orange 31 (CI. No. 20050), C.I. Pigment Red 144 (CI. No. 20735), C.I. Pigment Red 166 (CI. No. 20730), C.I. Pigment Red 220 (CI. No. 20055), C.I. Pigment Red 221 (CI. No. 20065), C.I. Pigment Red 242 (CI. No. 20067), C.I. Pigment Red 248, C.I. Pigment Red 262, CI. Pigment Brown 23 (CI. No. 20060), or the like; disazo- compound pigments, such as C.I. Pigment Yellow 13 (CI. No. 21 100), C.I. Pigment Yellow 83 (CI. No. 21108), C.I. Pigment Yellow 188 (CI. No. 21094), or the like; azo-compound pigments, such as C.I.
Pigment Red 187 (CI. No. 12486), CI. Pigment Red 170 (CI. No. 12475), C.I. Pigment Yellow 74 (CI. No. 1 1714), C.I. Pigment Yellow 150 (CI. No. 48545), C.I. Pigment Red 48 (CI. No. 15865), C.I. Pigment Red 53 (CI. No. 15585), C.I. Pigment Orange 64 (CI. No. 12760), CI. Pigment Red 247 (CI. No. 15915), or the like; indanthrone-compound pigments, such as CI. Pigment Blue 60 (CI. No. 69800), or the like; phthalocyanine-compound pigments, such as C.I. Pigment Green 7 (CI. No. 74260), C.I. Pigment Green 36 (CI. No. 74265), Pigment Green 37 (CI. No. 74255), Pigment Blue 16 (CI. No. 74100), C.I. Pigment Blue 75 (CI. No. 74160:2), C.I. Pigment Blue 15:6 (CI. No. 74160), C.I. Pigment Blue 15:3 (CI. No. 74160) or the like; triaryl carbonium-compound pigments, such as C.I. Pigment Blue 56 (CI. No. 42800), C.I. Pigment Blue 61 (CI. No. 42765: 1), or the like; dioxazine-compound pigments, such as C.I. Pigment Violet 23 (CI. No. 51319), C.I. Pigment Violet 37 (CI. No. 51345), or the like; aminoanthraquinone-compound pigments, such as C.I. Pigment Red 177 (CI. No. 65300), or the like; diketopyrrolopyrrole-compound pigments, such as C.I. Pigment Red 254 (CI. No. 561 10), C.I. Pigment Red 255 (CI. No. 561050), C.I.
Pigment Red 264, C.I. Pigment Red 272 (CI. No. 561 150), C.I. Pigment Orange 71, C.I. Pigment Orange 73, or the like; thioindigo-compound pigments, such as C.I. Pigment Red 88 (CI. No. 73312), or the like; isoindoline-compound pigments, such as C.I. Pigment Yellow 139 (CI. No. 56298), CI. Pigment Orange 66 (CI. No. 48210), or the like; isoindolinone-compound pigments, such as C.I. Pigment Yellow 109 (CI. No. 56284), C.I. Pigment Yellow 185 (CI. No. 56290), C.I. Pigment Orange 61 (CI. No. 1 1295), or the like; pyranthrone-compound pigments, such as C.I. Pigment Orange 40 (CI. No. 59700), C.I. Pigment Red 216 (CI. No. 59710), or the like; quinophthalone-compound pigments, such as C.I. Pigment Yellow 138; or isoviolanthrone-compound pigments, such as C.I. Pigment Violet 31 (CI. No. 60010), or the like. [0014] In the color filter of the present invention, two or more kinds of the organic pigment or solid solution thereof may be used in combination. Besides, they may be used together with ordinary dyes.
In the color filter of the present invention, the content of the organic pigment is preferably in the range of from 10 mass% to 70 mass%, more preferably from 30 mass% to 60 mass%, based on the total solid content in the colored layer. [0015]
(b) Monomer having a polymerizable group or oligomer having a polymerizable group
The monomer or oligomer having a polymerizable group used in the color filter of the present invention is preferably a monomer or oligomer which has two or more ethylenically unsaturated double bonds and which undergoes addition-polymerization by irradiation with light. The monomer or oligomer may be a compound having at least one addition-polymerizable ethylenically unsaturated group therein and having a boiling point of 100 0 C or higher at normal pressure. Examples thereof include: a monofunctional acrylate and a monofunctional methacrylate such as dipentaerythritol hexa(meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and phenoxyethyl(meth)acrylate; polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolethane triacrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane diacrylate, neopentyl glycol di(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, hexanediol di(meth)acrylate, trimethylolpropane tri(acryloyloxypropyl)ether, tri(acryloyloxyethyl)isocyanurate, tri(acryloyloxyethyl)cyanurate, glycerin tri(meth)acrylate; a polyfunctional acrylate or polyfunctional methacrylate which may be obtained by adding ethylene oxide or propylene oxide to a polyfunctional alcohol such as trimethylolpropane or glycerin and converting the adduct into a (meth)acrylate. Further, another preferred examples include those compounds that are obtained by addition reaction of ethylene oxide or propylene oxide to polyfunctional alcohol, followed by (meth)acrylation, as described in formulae (1) and (2) of JP-A- 10-62986. Herein, in the present specification, the expression "(meth)acrylate" is used to mean both "acrylate" and "methacrylate". [0016]
Examples of the monomer and oligomer having a polymerizable group further include urethane acrylates as described in JP-B-48-41708 ("JP-B" means examined Japanese patent publication), JP-B-50- 6034, and JP-A-51 -37193 ; and polyester acrylates as described in JP-A 48-64183, JP-B-49-43191 , and JP- B-52-30490; polyfunctional acrylates or polyfunctional methacrylates such as an epoxy acrylate which is a reaction product of an epoxy resin and (meth)acrylic acid.
Among these, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate,
dipentaerythritol hexa(meth)acrylate, and dipentaerythritol penta(meth)acrylate are preferable.
Further, other than the above, "polymerizable compound B" described in JP-A-1 1-133600 can be mentioned as a preferable example. [0017] These monomers or oligomers having a polymerizable group preferably have a molecular weight of 200 to 1000, and they may be used singly or as a mixture of two or more kinds thereof.
In the color filter of the present invention, the content of the monomer or oligomer having a polymerizable group is not particularly limited, but the content thereof is generally in a range of from 5 mass% to 50 mass%, preferably from 10 mass% to 40 mass%, in terms of the polymer in the colored layer, based on the total solid content in the colored layer. If this content is too large, control of development properties becomes difficult, raising problems of production suitability. If the content is too small, a curing force at the time of exposure becomes insufficient. [0018]
(c) Water-soluble polymer In the color filter of the present invention, the colored layer contains a water-soluble polymer.
The water-soluble polymer preferably has solubility to pure water (25 °C) of 10 or more, more preferably 50 or more, and especially preferably 100 or more. Also preferred are polymers that are neutral in the state of aqueous solution, which means that the polymers scarcely affect to the color filter. For example, preferred is a water-soluble compound whose 50 mass% aqueous solution shows pH of from 5 to 9, more preferably from 6 to 8. Specifically, use can be made of synthetic polymer compounds such as polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, polyethylene glycol, and polyethylene oxide, and copolymers of these compounds. Of these polymer compounds, polyvinyl pyrrolidone is especially preferred. These water-soluble polymers may be used singly or in combination of two or more kinds of polymers. [0019]
The molecular weight of the water-soluble polymer is not particularly limited, but a number- average molecular weight (Mn) thereof is preferably from 1,000 to 2,000,000, more preferably from 5,000 to 1,000,000, furthermore preferably from 10,000 to 500,000, and especially preferably from 10,000 to 100,000. [0020]
In the color filter of the present invention, the content of the water-soluble polymer in the colored layer is 0.1 mass% or more, preferably 0.5 mass% or more, and more preferably 1 mass% or more, based on the total solid content in the colored layer. There is no particular upper limit of the content of the water- soluble polymer in the colored layer, but it is practical that the content of the water-soluble polymer is 5 mass% or less, based on the total solid content of the colored layer. [0021]
(d) Binder
As the binder, preferred are binders having an acidic group. The binder may be added at the time of preparation of inkjet ink or colored photosensitive resin composition. It is also preferred to add the binder at the time of preparation of pigment dispersion, or prior to the preparation thereof, or alternatively at the time of formation of pigment fine particles as described later. The binder may be added to both or either of the organic pigment solution and the poor solvent used at the time of depositing pigment fine
particles by adding thereto the organic pigment solution. Alternatively, it is also preferred to add a binder solution separately at the time of formation of pigment fine particles.
[0022]
The binder is preferably an alkali-soluble polymer having a polar group such as a carboxylic acid group or a carboxylate group at its side chain. Examples thereof include a methacrylic acid copolymer, an acrylic acid copolymer, an itaconic acid copolymer, a crotonic acid copolymer, a maleic acid copolymer, and a partially esterified maleic acid copolymer described in, for example, JP-A-59-44615, JP-B-54-34327, JP-B-58-12577, JP-B-54-25957, JP-A-59-53836, and JP-A-59-71048. The examples further include a cellulose derivative having a carboxylic acid group or a carboxylate group at its side chain. In addition to the foregoing, a product obtained by adding a cyclic acid anhydride to a polymer having a hydroxyl group can also be preferably used. In addition, particularly preferable examples of the binder include a copolymer of benzyl (meth)acrylate and (meth)acrylic acid and a multi-component copolymer of benzyl (meth)acrylate, (meth)acrylic acid, and any other monomer, described in U.S. Patent No. 4,139,391. Each of these binder polymers having a polar group may be used singly, or may be used in combination with an ordinary film formable polymer so that they are used in a state of a composition.
The "alkali-soluble polymer" herein means a polymer whose acid strength is in the pH range of 1 or more but less than 5 when the pH of an aqueous solution containing 50 mass% of the polymer dissolved therein is measured. Based on the acid strength, the alkali-soluble polymer is distinguished from the above-described neutral water-soluble polymer. [0023]
Further, for the purpose of improving crosslinking efficiency, a polymerizable group may be included in the side chain, and ultraviolet curing resins and thermosetting resins are also useful. Examples of the polymers containing polymerizable groups are given below, but not limited to these, provided that an alkali soluble group, such as -COOH group, -OH group, and an ammonium group, and a carbon-carbon unsaturated bond, are included therein. For example, a compound which is obtained by reacting a compound having an epoxy ring, which has a reactivity with -OH group, and a carbon-carbon unsaturated bond group, such as glycidyl acrylate, with a copolymer which is composed of a monomer having -OH group, such as 2-hydroxyethylacrylate, a monomer having -COOH group, such as methacrylic acid, and a monomer which is copolymerizable with the forgoing two types of monomers, such as an acryl compound, a vinyl compound or the like, can be used. As the compound having a reactivity with -OH group, a compound having an acryloyl group, and an acid anhydride, and an isocyanate group, in place of the epoxy ring, can be used. Further, a reaction product which is obtained by reacting a saturated- or unsaturated- polybasic acid anhydride with a compound obtained by reacting a compound having an epoxy ring with an unsaturated carboxylic acid, such as acrylic acid, as disclosed in JP-A-6- 102669 and JP-A-6-1938 can also be used. Examples of the compound which has both an alkali-soluble group, such as a -COOH group, and a carbon-carbon unsaturated group include DIANAL NR series (trade name, manufactured by Mitsubishi Rayon Co., Ltd.), PHOTOMER 6173 (trade name; -COOH group-containing polyurethane acrylic oligomer, manufactured by Diamond Shamrock Co, Ltd.), VISCOAT R-264 and KS RESIST 106 (both trade names; manufactured by Osaka Organic Chemical Industry Ltd.), CYCLOMER P series and PRAXEL CF200 series (both trade names, manufactured by Daicel Chemical Industries, Ltd.), EBECRYL 3800 (trade name, manufactured by Daicel-UCB Company Ltd.), and the like. [0024]
Further as the binder resin, organic macromolecule polymers having a water-soluble atomic group at a part of side chains of the polymer can be used. It is preferable that the binder resin is a linear organic macromolecule polymer miscible with a monomer and is soluble in an organic solvent and an alkaline solution (preferably one developable with a weak alkaline aqueous solution). Examples of such an alkali-soluble resin include polymers which have a carboxylic acid in a side chain, such as the methacrylic acid copolymer, the acrylic acid copolymer, the itaconic acid copolymer, the crotonic acid copolymer, the maleic acid copolymer, the partially esterified maleic acid copolymer, and the like as disclosed in, for example, JP-A-59-44615, JP-A-54-34327, JP-A-58-12577, JP-A-54-25957, JP-A-59- 53836, and JP-A-59-71048. Similarly, acidic cellulose derivatives which have a carboxylic acid in a side chain are useful. In addition to these, a polymer having a hydroxyl group to which an acid anhydride is added, and the like are also useful as the aforementioned alkali-soluble resin. Specifically, benzyl(meth)acrylate/(meth)acrylic acid copolymers and multi-component copolymers of benzyl(meth)acrylate/(meth)acrylic acid/other monomer are particularly preferred among these polymers. As the above-described alkali-soluble resin, use can be made of a copolymer (hereinafter sometimes referred to as "copolymer A") composed of at least (i) at least one acid component monomer selected from maleic acid anhydride (MAA), acrylic acid (AA), methacrylic acid (MA), and fumaric acid (FA), and (ii) alkylpolyoxyethylene (meth)acrylate, and (iii) benzyl (meth)acrylate.
As the combination of the components in the above-described copolymer A, a composition ratio by mass of (i) an acid component monomer, (ii) alkylpolyoxyethylene (meth)acrylate (Acr(EO) n : CH 3 (OC 2 H 4 ) n OCOC(R)=CH 2 ), and (iii) benzyl(meth)acrylate (Bz(M)A) is preferably 10-25/5-25/50-85, and more preferably 15-20/5-20/60-80. Besides, an average molecular weight (Mw) of the above- described copolymer in terms of polystyrene, according to GPC is preferably in the range of from 3,000 to 50,000, and more preferably from 5,000 to 30,000. [0025] If the composition ratio by mass of (i) an acid component monomer is in the above-described range, alkali solubility and dissolution properties to solvents hardly decrease. Besides, if the composition ratio by mass of (ii) alkylpolyoxyethylene (meth)acrylate (Acr(EO) n : CH 3 (OC 2 H 4 ) n OCOC(R)=CH 2 ) is in the above-described range, a solution of the composition is easily spread onto a substrate, and also dispersibility of the coloring agent hardly decrease. Therefore, effects of the present invention can be effectively attained. If the composition ratio by mass of (iii) benzyl (meth)acrylate (Bz(M)A) is in the above-described range, dispersion stability of the coloring agent, dispersibility of the coloring agent in a composition, and alkaline development suitability of the coating film hardly decrease.
The repeating number n of the polyoxyethylene (EO)n in (ii) alkylpolyoxyethylene (meth)acrylate (Acr(EO) n : CH 3 (OC 2 H 4 ) π OCOC(R)=CH 2 ) is preferably in the range of from 2 to 15, more preferably from 2 to 10, and especially preferably from 4 to 10. If the repeating number n is in the above- described range, a development residue hardly generates after development with an alkaline developer. In addition, such the range can prevent generation of coating unevenness that is caused by reduction in fluidity of the composition as a coating solution. Consequently, said range can prevent deterioration in both uniformity of the coating film thickness and saving of liquid. These binder polymers having a polar group may be used singly or in the form of a composition containing the binder polymer together with an ordinary film-forming polymer. The addition amount of the binder polymer is generally in the range of from 10 to 200 mass parts, preferably from 25 to 100 mass
parts, based on 100 mass parts of pigment fine particles. [0026]
In the case where the binder is a polymer compound, the number of acid groups in the polymer compound is not particularly limited; but the number of repeating units each having an acid group(s) is preferably 5 to 100, and more preferably 10 to 100, when the number of repeating units in one molecule is set to 100. In addition, the polymerization ratio between (1) a repeating unit derived from a compound having a carboxyl group and (2) a repeating unit derived from a compound having a carboxylate group is preferably as follows: a ratio of the repeating unit (1) is 5 to 40 mol %, a ratio of the repeating unit (2) is 40 to 90 mol %, and a ratio of a repeating unit(s) except the repeating units (1) and (2) is 25 mol % or less. In addition, the molecular weight of the alkali-soluble binder polymer compound having an acid group is preferably 3,000 to 1,000,000, more preferably 4,000 to 200,000, and particularly preferably 5,000 to 80,000. [0027]
As to the content of the binder in the color filter of the present invention, there is no particular limitation. However, the content of the binder in a colored layer is generally in the range of from 15 to 50 mass%, preferably from 20 to 45 mass%, based on the total solid content in the colored layer. If the amount of the binder is too large, viscosity of a pigment dispersion used at the time of production of the color filter becomes too high, which causes problem in production suitability. On the other hand, if the amount of the binder is too small, problems in coating film formation arise. [0028]
(e) Photopolymerization initiator or photopolymerization initiator series
Examples of the photopolymerization initiator or the photopolymerization initiator series (in the present specification, the term "photo-polymerization initiator series" means a polymerization initiating composition that exhibits a function of photo-polymerization initiation with a plurality of compounds combined with each other) include vicinal polyketaldonyl compounds disclosed in U.S. Patent No.
2,367,660, acyloin ether compounds described in U.S. Patent No. 2,448,828, aromatic acyloin compounds substituted by an α-hydrocarbon described in U.S. Patent No. 2,722,512, polynuclear quinine compounds described in U.S. Patent No. 3,046,127 and U.S. Patent No. 2,951,758, combinations of triarylimidazole dimer and p-aminoketone described in U.S. Patent No. 3,549,367, benzothiazole compounds and trihalomethyl-s-triazine compounds described in JP-B-51-48516, trihalomethyl-triazine compounds described in U.S. Patent No. 4,239,850, and trihalomethyloxadiazole compounds described in U.S. Patent No. 4,212,976. In particular, trihalomethyl-s-triazine, trihalomethyloxadiazole, and triarylimidazole dimer are preferable. [0029] In addition, "polymerization initiator C" described in JP-A-11-133600, and oximes such as 1- phenyl-l,2-propanedion-2-(o-ethoxycarbonyl)oxime, O-benzoyl-4'-(benzmercapto)benzoyl-hexyl-ketoxime, 2,4,6-trimethylphenylcarbonyl-diphenylphosphonyloxide, and hexafluorophosphoro-trialkylphenyl phosphonium salt can also be mentioned as preferable examples. [0030] These photopolymerization initiators and photopolymerization initiator series each may be used singly. Alternatively, a mixture of two or more selected from these photopolymerizable initiators and photopolymerization initiator series may be used. In particular, it is preferable to use two or more selected
from photopolymerizable initiators and photopolymerization initiator series. When two or more selected from photopolymerizable initiators and photopolymerization initiator series are used, the display property, particularly evenness of display, can be improved. [0031] As to the content of the photo-polymerization initiator and the photo-polymerization initiator series used in the color filter of the present invention, there is no particular limitation. However, the content thereof in a colored layer is generally in the range of from 0.5 to 20 mass%, preferably from 1 to 15 mass%, based on the total solid content in the colored layer. If the amount of the initiator or the initiator series is too large, exposure sensitivity becomes too high, which causes difficulty in control. If the amount of the initiator or the initiator series is too small, exposure sensitivity becomes too low. [0032]
In addition to the above-described components, an organic solvent may further be used. There is no limitation as to the organic solvent. Examples of the organic solvent include esters, such as ethyl acetate, n-butyl acetate, isobutyl acetate, amyl formate, isoamyl acetate, isobutyl acetate, butyl propionate, isopropyl butylate, ethyl butylate, butyl butylate, an alkyl ester compound, methyl lactate, ethyl lactate, methyl oxyacetate, ethyl oxyacetate, butyl oxyacetate, methyl methoxyacetate, ethyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, alkyl 3-oxypropionate compound (e.g. methyl 3-oxypropionate and ethyl 3-oxypropionate), methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate; methyl 2-oxypropionate, ethyl 2-oxypropionate, propyl 2-oxypropionate, methyl 2-methoxypropionate, ethyl 2-methoxypropionate, propyl 2- methoxypropionate, methyl 2-ethoxypropionate, ethyl 2-ethoxypropionate, methyl 2-oxy-2- methylpropionate, ethyl 2-oxy-2-methylpropionate, methyl 2-methoxy-2-methylpropionate, ethyl 2-ethoxy- 2-methylpropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl 2-oxobutanoate, and ethyl 2-oxobutanoate; ethers, such as diethylene glycol dimethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methylcellosolve acetate, ethylcellosolve acetate, diethylene glycol monomethyl ether, propylene glycol methyl ether acetate; ketones, such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclohexanol, 2-heptanone, and 3-heptanone; and aromatic hydrocarbons, such as toluene and xylene. Among these solvents, as the solvent to be used in the present invention, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl cellosolve acetate, ethyl lactate, butyl acetate, methyl 3-methoxypropionate, 2- heptanone, cyclohexanone, ethyl carbitol acetate, butyl carbitol acetate, propylene glycol methyl ether acetate and the like are preferable. These solvents may be used singly or in combination of two or more thereof. [0033] Further, if necessary, a solvent having a boiling point of from 180 °C to 250 0 C may be used.
Examples of the high boiling solvent include diethyleneglycol monobutylether, diethyleneglycol monoethyletheracetate, diethyleneglycol monoethylether, 3,5,5-trimethyl-2-cyclohexene-l-on, butyl lactate, dipropyleneglycol monomethyletheracetate, propyleneglycol monomethyletheracetate, propyleneglycol diacetate, propyleneglycol-n-propyletheracetate, diethyleneglycol diethylether, 2-ethylhexylacetate, 3- methoxy-3-methylbutylacetate, γ-butyllactone, tripropyleneglycol methylethylacetate, dipropyleneglycol n- butylacetate, propyleneglycol phenyletheracetate, and 1,3-butanediol diacetate.
The content of the solvent in the color filter of the present invention is not particularly limited.
However, it is preferred that the content of the solvent be 10 to 95 mass % in the pigment dispersion. [0034]
Conventional color filters had a problem that the color of each pixel was deep in order to realize a high color purity, whereby unevenness of the film thickness of pixels was directly recognized as color unevenness. For this reason, it has been desired to suppress the film thickness variation, which directly influences the film thickness of pixels.
In the color filter of the present invention, the inkjet ink for color filter preferably comprises a suitable surfactant from the viewpoint of achieving a uniform film thickness and of prevention of color unevenness caused by variation in the film thickness effectively. Preferable examples of the surfactant include surfactants disclosed in JP-A-2003-337424 and JP-
A-1 1-133600. The content of the surfactant in the color filter of the present invention is not particularly limited. However, it is preferred that the content of the surfactant be 5 mass% or less based on the total solid content in the colored layer. [0035] It is preferred that the color filter of the present invention include a thermal polymerization inhibitor. Examples of the thermal polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'- thiobis(3-methyl-6-t-butylphenol), 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2-mercaptobenzimidazole, and phenothiazine. The content of the thermal polymerization inhibitor in the color filter of the present invention is not particularly limited. However, it is preferred that the content of the thermal polymerization inhibitor in a colored layer be 1 mass% or less based on the total solid content in the colored layer.
[0036]
If necessary, the color filter of the present invention may include an ultraviolet absorber. Examples of the ultraviolet absorber include compounds disclosed in JP-A-5-72724, a sal icy late-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, a benzotriazole-based ultraviolet absorber, a cyanoacrylate-based ultraviolet absorber, a nickel-chelate-based ultraviolet absorber, and a hindered- amine-based ultraviolet absorber.
Specific examples thereof include phenyl salicylate, 4-t-butyl phenylsalicylate, 2,4-di-t-butyl phenyl-3',5'-di-t-4'-hydroxybenzoate, 4-t-butyl phenylsalicylate, 2,4-dihydroxybenzophenone, 2-hydroxy-4- methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriaz ole, ethyl-2-cyano-3,3-diphenyl acrylate, 2,2'- hydroxy-4-methoxybenzophenone, nickel dibutyl dithiocarbamate, bis(2,2,6,6-tetramethyl-4-pyridine)- sebacate, 4-t-butyl phenylsalicylate, phenyl salicylate, 4-hydroxy-2,2,6,6-tetramethylpiperidine condensate, succinic acid-bis(2,2,6,6-tetramethyl-4-piperidenyl)-ester, 2-[2-hydroxy-3,5-bis(α,α- dimethylbenzyl)phenyl]-2H-benzotriazole, and 7-{[4-chloro-6-(diethylamino)-5-triazine-2-yl]amino}-3- phenylcoumarin. The content of the ultraviolet absorber in the color filter of the present invention is not particularly limited. However, it is preferred that the content of the ultraviolet absorber be 5 mass% or less based on the total solid content in the colored layer. [0037]
In the color filter of the present invention, the pigment dispersion may be used in the form of an inkjet ink at the time of preparation of a colored layer. It is preferred to control the temperature of the ink
so that a deviation of viscosity of the ink would be within ±5%. The viscosity at the time of injection is preferably from 5 to 25 mPa-s, more preferably from 8 to 22 mPa-s, and especially preferably from 10 to 20 mPa-s (the viscosity used in the present specification is a value at 25 0 C, unless specifically indicated otherwise). In addition to setting of the above-described injection temperature, the viscosity may be adjusted by controlling the kind of components to be contained in the ink and the amount thereof. The viscosity may be measured using ordinary equipments such as a cone-and-plate-system rotational viscometer and an E type viscometer.
It is preferred that the surface tension of the ink at the time of injection be from 15 to 40 mN/m, from the viewpoint of improvement in smoothness (flatness) of the pixel (surface tension used in the present specification is a value at 23 °C unless specifically indicated otherwise). The surface tension is more preferably from 20 to 35 mN/m, and most preferably from 25 to 30 mN/m. The surface tension may be adjusted by adding surfactants and selecting the kind of solvent to be used. The surface tension may be measured according to a platinum plate method using known measuring equipments such as a surface tension-measuring device (CBVP-Z, manufactured by Kyowa Interface Science Co., Ltd.) and a full automatic balancing type electro surface tensiometer ESB-V (manufactured by Kyowa Science). [0038]
As a method of spraying the above-described pigment dispersion as an inkjet ink for color filter, it is possible to employ any of various methods such as a method of continuously spraying an electrified ink and then controlling the ink by electric field, and a method of intermittently spraying an ink using a piezoelectric element, and a method of intermittently spraying an ink with utilizing bubbles generated by heating the ink.
As to the inkjet method used for forming each pixel (image element), any of ordinary methods such as a method of thermally curing an ink, a photo-curing method, and a method of previously forming a transparent image-receiving layer on a substrate, followed by stroke of ink droplets. [0039]
As an inkjet head (hereinafter sometimes simply referred to as a head), ordinary heads, such as continuous type heads and dot-on-demand type heads can be used. Of these dot-on-demand-type heads, preferred as thermal heads are those of the type having a movable bulb for discharge as described in JP-A- 9-323420. As the piezo head, use can be made of heads described in, for example, EP 277,703 A and EP 278,59OA. It is preferred that the head have a temperature control function so that the temperature of the ink can be managed. Specifically, it is preferred to set an injection temperature so that the viscosity at the time of injection would be within the range of from 5 to 25 mPa-s and to control the temperature of the ink so that the deviation of the viscosity would be within ±5%. It is preferred that the head operate with a drive frequency in the range of from 1 to 500 kHz. [0040]
After formation of each pixel (image element), it is possible to set a heat step in which a thermal processing (a so-called bake processing) is performed. In the heat step, a substrate having thereon a layer photo-polymerized by light irradiation is heated in a heating machine such as an electric furnace and a drying oven, or alternatively said substrate is irradiated using an infrared lamp. The temperature and time required for heating depends on a composition of the colored photosensitive composition and the thickness of the formed layer. Generally, it is preferred to heat at a temperature of from about 120 0 C to about 250 0 C for a period of time ranging from about 10 minutes to about 120 minutes, from such the viewpoints of
attaining sufficient solvent resistance, alkali resistance, and ultraviolet absorbance.
The pattern shape of the thus-formed color filter is not particularly limited. Accordingly, it may be a stripe shape, which is a general black matrix shape, or a lattice shape, or a delta configuration shape. [0041] It is preferred to use a preparation method in which a barrier rib is formed prior to the image element-forming step using an inkjet ink for color filter, and then the ink is supplied to a portion surrounded with the barrier rib. The barrier rib is not particularly limited. However, in the case where a color filter is formed, it is preferred to use a barrier rib having a black matrix function and a light shielding effect (hereinafter, such the barrier rib is simply referred to as "barrier rib"). The barrier rib may be prepared by the same materials and according to the same method as ordinary black matrixes for color filter. Examples of the black matrix include those described in paragraphs [0021] to [0074] of JP-A-2005-3861 and paragraphs [0012] to [0021] of JP-A-2004-240039, and black matrixes for inkjet described in paragraphs [0015] to [0020] of JP-A-2006- 17980 and paragraphs [0009] to [0044] of JP-A-2006-10875. [0042] The above-described pigment dispersion may be used in a form of a colored photosensitive resin composition, to form a coating film. Herein, the "colored photosensitive resin composition" refers to a composition containing the pigment dispersion. The thickness of the coating film may be properly determined. However, the thickness is preferably in the range of from 0.5 μm to 5.0 μm, and more preferably from 1.0 μm to 3.0 μm. In the coating film formed using the colored photosensitive resin composition, a polymerized coating of the colored photosensitive resin composition may be formed by polymerizing a monomer or oligomer having a polymerizable group incorporated in the composition, thereby to prepare a color filter having the thus-formed polymerized coating. (A preparation of the color filter will be described later.) Polymerization of the monomer or oligomer having a polymerizable group may be performed by causing a photo-polymerization initiator or a photo-polymerization initiator series to act by irradiation of light. [0043]
The aforementioned coating film can be formed by coating the colored photosensitive resin composition by a known coating method, followed by drying. It is preferred that the colored photosensitive resin composition be coated by using a slit nozzle having a slit at a portion through which the coating liquid is discharged. Specifically, preferable are slit nozzles and slit coaters described in JP-A- 2004-89851, JP-A-2004- 17043, JP-A-2003-170098, JP-A-2003-164787, JP-A-2003-10767, JP-A-2002- 79163, and JP-A-2001-310147. [0044]
As a method of coating a colored photosensitive resin composition on a substrate, a spin coating is excellent in such the point that a thin film of 1 μm to 3 μm can be uniformly coated with high precision.
Therefore, the spin coating can be widely and generally used for preparation of color filters. In recent yeas, however, it is required to further improve production efficiency and production cost in accordance with inclination to large-sized liquid crystal display devices and mass production thereof. Therefore, the slit coating, which is more suited for coating on a wide and large area substrate than the spin coating, has been adopted in production of color filters. Besides, the slit coating is superior to the spin coating from the viewpoint of saving of liquid to be used; and the slit coating can obtain a uniform coating from a lesser coating amount.
[0045]
The slit coating is a coating method characterized by the steps of using a coating head having a slit (gap) of a width of several ten microns at a tip and having a length corresponding to the coating width of a rectangular substrate, and moving the substrate and/or the coating head at a definite relative speed, while maintaining a clearance (gap) between the substrate and the coating head at a distance of from several ten microns to several hundred microns, and coating on the substrate a coating liquid fed from the slit in a predetermined discharge amount. The slit coating has such advantages as follows: (1) a liquid loss is less than a spin coating; (2) a workload at the time of conducting a wash processing is reduced because no coating liquid would be spattered; (3) no contamination (re-inclusion) owing to the spattered liquid component to a coating film would be caused; (4) a tact time is shortened because no dwell time to start up spinning is necessary; (5) it easily coats a large-sized substrate. From these advantages, the slit coating is suitable to production of a color filter for a large-sized-screen liquid crystal display device, and the slit coating has been expected as a coating method that is also useful for reduction in a coating amount of the liquid. [0046]
A coating film of much larger area can be formed by the slit coating than the spin coating. Therefore, it is necessary to keep a certain degree of relative speed between a coater and a material to be coated at the time when a coating liquid is discharged from a wide slit exit. For this reason, a good fluidity is required to a coating liquid used for the slit coating method. Further, it is particularly required for the slit coating to maintain various conditions of the coating liquid fed from a slit of the coating head to a substrate constant over the entire coating width. If solution physical properties such as fluidity and viscoelastic properties of the coating liquid are insufficient, a coating unevenness easily occurs, so that it becomes difficult to keep a coating thickness constant toward the direction of a coating width. Consequently, the coating unevenness causes such the problem that it is difficult to obtain a uniform coating. [0047]
In view of the above, various studies on improvement of fluidity and viscoelastic properties of the coating liquid have been made in order to obtain a uniform coating film with no unevenness. As mentioned above, many means have been proposed such as reduction in molecular weight of a polymer, selection of a polymer excellent in solubility in a solvent, selection from various solvents in order to control an evaporation rate, and application of a surfactant. However, these means were not satisfactory to improve the above-described problems. [0048]
A photosensitive resin transfer material may be prepared by providing a photosensitive resin layer using the aforementioned colored photosensitive resin composition. The photosensitive resin transfer material is preferably formed by using a composite film, similarly to the photosensitive resin transfer material described in JP-A-5-72724. The structure of the composite film may be, for example, a lamination in which a temporary support, a thermoplastic resin layer, an intermediate layer, a photosensitive resin layer, and a protective film are disposed in this order. [0049] It is necessary that the temporary support has flexibility and does not remarkably deform, shrink, or elongate even under pressure or under pressure and heat. Examples of such a temporary support include a polyethylene terephthalate film, a cellulose triacetate film, a polystyrene film, and a polycarbonate
film. Among them, a biaxially-stretched polyethylene terephthalate film is particularly preferable. [0050]
The component used in the thermoplastic resin layer is preferably an organic polymer substance described in JP-A-5-72724. The substance is more preferably an organic polymer substance having a softening point of about 80 °C or lower according to the Vicat method (specifically, the method of measuring a polymer softening point according to American Material Test Method ASTMD 1235). Specifically, the substance may be an organic polymer, and examples thereof include: a polyolefin such as polyethylene or polypropylene; an ethylene copolymer such as a copolymer of ethylene and vinyl acetate or a saponified product thereof; a copolymer of ethylene and acrylic acid ester or a saponified product thereof; polyvinyl chloride; a vinyl chloride copolymer such as a copolymer of vinyl chloride and vinyl acetate or a saponified product thereof; polyvinylidene chloride; a vinylidene chloride copolymer; polystyrene; a styrene copolymer such as a copolymer of styrene and (meth)acrylic acid ester or a saponified product thereof; polyvinyl toluene; a vinyltoluene copolymer such as a copolymer of vinyltoluene and (meth)acrylic acid ester or a saponified product thereof; poly(meth)acrylic acid ester; a (meth)acrylic acid ester copolymer such as a copolymer of butyl (meth)acrylate and vinyl acetate; and a polyamide resin such as a vinyl acetate copolymer nylon, a copolymerized nylon, N-alkoxymethylated nylon, and N-dimethylaminated nylon. [0051]
In the photosensitive resin transfer material, it is preferable to provide an intermediate layer so as to prevent mixing of components during application of a plurality of coating layers and during storage after the application. The intermediate layer is preferably an oxygen blocking film having oxygen blocking function described as "a separating layer" in JP-A-5-72724. By using such an oxygen blocking film, the exposure sensitivity is heightened, the time load of the exposing machine is decreased, and the productivity is improved.
The oxygen blocking film is preferably a film with a low oxygen permeability and is dispersible or soluble in water or an aqueous alkaline solution. Such a film may be properly selected from known oxygen blocking films. Among them, a combination of polyvinyl alcohol and polyvinylpyrrolidone is particularly preferable. [0052]
It is preferable to provide a thin protective film on a photosensitive resin layer in order to protect the photosensitive resin layer from pollution or damage at storage. The protective film may comprise a material which is the same as or similar to that of the temporary support, but the protective film should be easily separated from the photosensitive resin layer. The protective film material may be, for example, silicone paper, polyolefin sheet or polytetrafluoroethylene sheet. [0053] The photosensitive resin transfer material can be prepared by: coating a temporary support with a coating liquid (coating liquid for thermoplastic resin layer) in which additives for a thermoplastic resin layer are dissolved and drying the coating liquid to form a thermoplastic resin layer; and then coating the thermoplastic resin layer with a coating liquid for intermediate layer containing a solvent which does not dissolve the thermoplastic resin layer, and drying the coating liquid for intermediate layer; and then, coating the intermediate layer with a coating liquid for photosensitive resin layer containing a solvent which does not dissolve the intermediate layer, and drying the coating liquid for photosensitive resin layer.
Alternatively, the photosensitive resin transfer material may be prepared by: preparing a sheet in
which a thermoplastic resin layer and an intermediate layer are disposed on the aforementioned temporary support, and a sheet in which a photosensitive resin layer is disposed on a protective film, and adhering the sheets to each other such that the intermediate layer and the photosensitive resin layer contact each other. The photosensitive resin transfer material may also be prepared by: preparing a sheet in which a thermoplastic resin layer is disposed on the aforementioned temporary support, and a sheet in which a photosensitive resin layer and an intermediate layer are disposed on a protective film, and adhering the sheets to each other such that the thermoplastic resin layer and the intermediate layer contact each other. [0054]
In the photosensitive resin transfer material, the thickness of the photosensitive resin layer is preferably 1.0 to 5.0 μm, more preferably 1.0 to 4.0 μm, and particularly preferably 1.0 to 3.0 μm. In general, the thickness of the temporary support is preferably 15 to 100 μm, the thickness of the thermoplastic resin layer is preferably 2 to 30 μm, the thickness of the intermediate layer is preferably 0.5 to 3.0 μm, and the thickness of the protective film is preferably 4 to 40 μm. However, the thicknesses of respective layers are not limited to the above ranges. [0055]
Coating operation in the above methods may be performed by a known coating apparatus. In the present invention, it is preferable to conduct the coating operation with a coating apparatus (slit coater) using a slit nozzle. Preferable examples of the slit coater are as described above. [0056] The color filter of the present invention may have only a single hue, or three different hues such as red, blue, and green, or alternatively four different hues further including black, according to an end use. There is no particular limitation on a pattern of the colored layer on a substrate and a method of forming the pattern.
The color filter of the present invention may be used as a color filter excellent in contrast. The term "contrast" used in the present specification means a ratio of the amount of transmitted light when polarization axes are parallel to the amount of transmitted light when polarization axes are perpendicular, with respect to a color filter placed between two polarizing plates (see, for example, The 7th Color Optics Conference 1990; Color Filter for 512-color 10.4"-size TFT-LCD; Ueki, Koseki, Fukunaga, Yamanaka).
The color filter having a high contrast enables enlarging a discrimination of brightness at the time when the color filter is combined with a liquid crystal. Therefore, the high contrast is a very important performance in enhancing replacement of CRTs by liquid crystal display devices. The contrast of the color filter according to the present invention is, if it is a monochromatic type, preferably 3,000 or more, more preferably 5,000 or more, and especially preferably 7,000 or more. With respect to a color filter having R pixel, G pixel, and B pixel, and, if necessary, further provided with a black matrix, the contrast is preferably 3,000 or more, more preferably 5,000 or more, and especially preferably 6,000 or more. The present invention is characterized in that such a high contrast can be realized thereby. [0057]
In the case where the color filter of the present invention is used as a color filter for a television monitor, the difference (δE) between the chromaticity of the red (R) photosensitive resin layer measured under a FlO light source and the target chromaticity for red shown in the following table, the difference (δE) between the chromaticity of the green (G) photosensitive resin layer measured under a FlO light source and the target chromaticity for green shown in the following table, the difference (δE) between the
chromaticity of the blue (B) photosensitive resin layer measured under a FlO light source and the target chromaticity for blue shown in the following table, are each preferably 5 or less, more preferably 3 or less, still more preferably 2 or less. [0058]
[0059]
Herein, chromaticity in the present invention is measured by a microscopic spectrophotometer
(OSPlOO or 200, manufactured by Olympus Optics) and expressed in terms of xyY values of the xyz color system obtained by calculation as a result under an F10-light source at 2-degree viewing angle. In addition, the difference from the target chromaticity is expressed in terms of a color difference of a La*b* color system.
[0060]
The color filter of the present invention can be produced by, for example, a method of repeating, until the layers of the respective colors are provided, the process comprising: forming a photosensitive resin layer on a substrate; and exposing and developing the photosensitive resin layer. Black matrix may be introduced so as to partition the boundaries of the photosensitive resin layers, in accordance with the necessity.
In the above production method, formation of the photosensitive resin layer on a substrate may be conducted, for example, by (a) applying the respective colored photosensitive resin compositions by a known coating device or by (b) using the aforementioned photosensitive resin transfer material so as to adhere the photosensitive resin layer by a laminator.
[0061]
Any of known coating apparatuses may be used for applying the colored photosensitive resin composition, when producing the color filter of the present invention. Among these, a slit-coater is particularly preferably used. Preferable examples of the slit coater are as described above. When the photosensitive resin layer is formed by coating, its film thickness is preferably 1.0 to 3.0 μm, more preferably 1.0 to 2.5 μm, and still more preferably 1.5 to 2.5 μm.
[0062]
Using the photosensitive resin transfer material, the photosensitive resin layer formed into a film shape may be adhered to the substrate previously explained by a heated and/or pressurized roller or flat plate by pressure adhesion or heat pressure adhesion. Specifically, laminators and laminating methods described in the following documents may be used: JP-A-7-1 10575, JP-A-11-77942, JP-A-2000-334836, and JP-A-2002- 148794. From the viewpoint of suppression of contamination by foreign substances, it is preferable to use the method described in JP-A-7-1 10575. In the color filter of the present invention, when the photosensitive resin layer is formed by application of the colored photosensitive resin composition, an oxygen blocking film may further be provided on the photosensitive resin layer, whereby the exposure sensitivity can be improved. As the
oxygen blocking film, those explained in the above can be mentioned. The thickness of the oxygen blocking film is not particularly limited, and the thickness is preferably 0.5 to 3.0 μm in general. [0063]
The color filter of the present invention can be obtained by repeating, until the resin layers of the respective colors are provided, the process comprising: arranging a predetermined mask over a photosensitive resin layer formed on a substrate; exposing the photosensitive resin layer to light from above the mask which has passed through the mask, the thermoplastic resin layer, and the intermediate layer, and then developing the photosensitive resin layer with a developer.
The light source for the exposure can be suitably selected from light sources capable of emitting lights within the wavelength region capable of curing the photosensitive resin layer (e.g. 365 nm, 405 nm, etc.). Specific examples thereof include an ultrahigh-pressure mercury lamp, a high-pressure mercury lamp, and a metal halide lamp. The exposure amount is usually about 5 to 200 mJ/cm 2 , and preferably about 10 to 100 mJ/cm 2 . [0064] The developer is not particularly limited and may be a known developer such as the developer described in JP-A-5-72724. The developer is preferably a developer of a type which dissolves uncured photosensitive resin layer during development; for example, a developer containing a compound with a pKa of 7 to 13 at a concentration of 0.05 to 5 mol/L is preferable. The developer may include a small amount of an organic solvent miscible with water. Examples of the organic solvent miscible with water include methanol, ethanol, 2-propanol, 1- propanol, butanol, diacetonealcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-butyl ether, benzyl alcohol, acetone, methyl ethyl ketone, cyclohexanone, ε- caprolactone, γ-butyrolactone, dimethylformamide, dimethylacetamide, hexamethylphosphoramide, ethyl lactate, methyl lactate, ε-caprolactam, and N-methylpyrrolidone. The concentration of the organic solvent is preferably 0.1 mass% to 30 mass%.
A known surfactant may be further added to the developer. The concentration of the surfactant is preferably 0.01 mass% to 10 mass%. [0065]
The developing method may be a known method such as paddle development, shower development, shower & spin development, or dip development.
Herein, the shower development will be explained. In the shower development, the developer is sprayed onto the exposed photosensitive resin layer with a shower, so that the uncured portion is removed. It is preferable to spray an alkaline solution having poor ability to dissolve the photosensitive resin layer by using a shower on the like before development, so as to remove the thermoplastic resin layer and the intermediate layer. Further, after development, it is preferable to spray a cleaner or the like by using a shower while rubbing the surface with a brush or the like to remove the development residue.
The liquid temperature of the developer is preferably 20 0 C to 40 0 C, and the pH of the developer is preferably 8 to 13. [0066] In an embodiment of the present invention, at the time of the production of the color filter of the present invention, the colored photosensitive resin composition for forming a color filter are stacked to form a base, a transparent electrode is formed thereon, and protrusions for split-orientation is further provided
thereon to form a spacer, as described in JP-A- 1 1 -248921 and Japanese Patent No. 3255107. This embodiment is preferable from the viewpoint of cost reduction.
When the colored photosensitive resin compositions are stacked by successive coating operations, the film thickness becomes smaller in every overlaying owing to the leveling of the coating liquid. For this reason, it is preferable to stack the four colors of K (black), R, G, and B and to provide protrusions for split-orientation thereon. On the other hand, when the transfer material having a thermoplastic resin layer is used, it is preferable to stack two or three colors since the thicknesses are maintained constant.
In order to prevent deformation of the photosensitive resin layer upon lamination by overlaying the transfer material and to maintain a constant thickness, the size of the base is preferably 25 μm x 25 μm or larger, more preferably 30 μm x 30 μm or larger. [0067]
The liquid crystal display device of the present invention is excellent in definition such as black depth owing to the use of the color filter that is excellent in contrast according to the present invention. The liquid crystal display device of the present invention can be suitably used also as a large screen liquid crystal display device such as a display for a notebook computer and a television monitor. [0068]
As mentioned above, it is preferred that pigment dispersion used in the color filter of the present invention contain pigment fine particles. It is more preferred that the pigment fine particles are formed (deposited) by mixing an organic pigment solution of the organic pigment dissolved in a good solvent, together with a solvent that has compatibility with the good solvent but functions as a poor solvent for the organic pigment (hereinafter, this solvent is sometimes referred to as a "poor solvent for the organic pigment" or simply as a "poor solvent"). (Hereinafter, this method is sometimes referred to as a "fine particle deposition method"). In this connection, it is necessary for a good solvent and a poor solvent chosen for combination to show a sufficient difference between their solubility for the organic pigment; and it is necessary to select proper solvents depending on the pigment to be used. However, any combination of solvents may be employed as long as they can carry out the above-described steps. [0069]
The poor solvent for the organic pigment is not particularly limited as long as the solvent is compatible, or mixes uniformly, with a good solvent used to dissolve the organic pigment. With respect to the poor solvent for the organic pigment, the solubility of the organic pigment in the poor solvent is preferably 0.02 mass% or less, more preferably 0.01 mass% or less. The solubility of the organic pigment in the poor solvent has no particular lower limit, but it is practical that the solubility is 0.000001 mass% or more in consideration of an organic pigment to be ordinarily used. The solubility may be solubility in the case where the organic material is dissolved in the presence of an acid or an alkali. Further, compatibility or uniform mixing property between the good solvent and the poor solvent is such that the amount of the good solvent soluble in the poor solvent is preferably 30 mass% or more, more preferably 50 mass% or more. The amount of the good solvent soluble in the poor solvent has no particular upper limit, but it is practical that the solvents can mix with each other at an arbitrary ratio. [0070] Examples of the poor solvents include aqueous solvents (e.g., water, hydric alcohol, hydrochloric acid, and aqueous sodium hydroxide solution), alcohol compound solvents, ketone compound solvents, ether compound solvents, aromatic compound solvents, carbon disulfide solvents, aliphatic compound
solvents, nitrile compound solvents, halogen-containing compound solvents, ester compound solvents, ionic solvents, and mixed solvents thereof. Preferable examples of the poor solvents include aqueous solvents, alcohol compound solvents, ketone compound solvents, ether compound solvents, ester compound solvents, and mixed solvents thereof; and more preferable examples of the poor solvents include aqueous solvents, alcohol compound solvents, and ester compound solvents. [0071]
Examples of the alcohol compound solvents include methanol, ethanol, isopropyl alcohol, n- propyl alcohol, l-methoxy-2-propanol, and the like. Examples of the ketone compound solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and the like. Examples of ether compound solvents include dimethylether, diethylether, tetrahydrofuran, and the like. Examples of the aromatic compound solvents include benzene, toluene, and the like. Examples of the aliphatic compound solvents include hexane, and the like. Examples of the nitrile compound solvents include acetonitrile, and the like. Examples of the halogen-containing compound solvents include dichloromethane, trichloroethylene, and the like. Examples of the ester compound solvents include ethyl acetate, ethyl lactate, 2-(l-methoxy)propyl acetate, and the like. Examples of the ionic solvents include a salt of 1-butyl- 3-methylimidazolium and PF 6 " , and the like. [0072]
The good solvent is not particularly limited as long as it can dissolve the organic pigment to be used, and is compatible, or uniformly mixed, with the aforementioned poor solvent. With respect to the solubility of the organic pigment in the good solvent, the solubility of the organic pigment is preferably 0.2 mass% or more, and more preferably 0.5 mass% or more. The solubility of the organic pigment in the good solvent has no particular upper limit, but it is practical that the solubility is 50 mass% or less in consideration of an organic material to be ordinarily used. The solubility may be solubility in the case where the organic material is dissolved in the presence of an acid or an alkali. A preferable range for compatibility or uniform mixing property between the poor solvent and the good solvent is as described above. [0073]
Examples of the good solvents include alcohol compound solvents, amide compound solvents, ketone compound solvents, ether compound solvents, aromatic compound solvents, carbon disulfide solvents, aliphatic compound solvents, nitrile compound solvents, sulfoxide compound solvents, halogen- containing compound solvents, ester compound solvents, ionic liquids, mixed solvents thereof, and the like. Among these, alcohol compound solvents, ketone compound solvents, ether compound solvents, sulfoxide compound solvents, ester compound solvents, amide compound solvents, and the mixed solvents thereof are preferable; alcohol compound solvents, ester compound solvents, sulfoxide compound solvents, and amide compound solvents are more preferable; and sulfoxide compound solvents and amide compound solvents are particularly preferable. [0074]
Examples of the sulfoxide compound solvent include dimethyl sulfoxide, diethyl sulfoxide, hexamethylene sulfoxide, and sulfolane. Examples of the amide compound solvent include N 5 N- dimethylformamide, 1 -methyl-2-pyrrolidone, 2-pyrrolidinone, l,3-dimethyl-2-imidazolidinone, 2- pyrroridinone, ε-caprolactam, formamide, N-methylformamide, acetamide, N-methylacetamide, N,N- dimethylacetamide, N-methylpropaneamide, and hexamethylphosphoric triamide.
[0075]
In addition, the concentration of the organic pigment solution prepared by dissolving the organic pigment in the good solvent is preferably in the range of the saturation concentration of the organic pigment with respect to the good solvent under conditions at the time of the dissolution to about one hundredth of the saturation concentration.
The condition under which the organic pigment solution is prepared is not particularly restricted, and can be selected from a range from a normal pressure condition to a subcritical or supercritical condition. The temperature in the case where the solution is prepared under normal pressure is preferably -10 to 150 C C, more preferably -5 to 130 0 C, and particularly preferably 0 to 100 0 C. [0076]
The above-described examples of the good solvent and those of the poor solvents overlap, but the identical solvent is not selected for both the good solvent and the poor solvent. Any solvents may be used in combination of them as long as an organic material to be used shows solubility in the good solvent sufficiently higher than that in the poor solvent. Specifically, the difference in solubility between them is preferably 0.2 mass% or more, and more preferably 0.5 mass% or more. There is no particular upper limit to the difference in solubility between the good solvent and the poor solvent. However, if ordinarily used organic materials are taken into consideration, it is practical that the upper limit is 50 mass% or less. [0077]
In the aforementioned fine particle deposition method, it is preferred that the organic pigment be uniformly dissolved in the good solvent, and further it is preferred that the organic pigment be dissolved when the solvent is acidic or alkaline. In general, in the case of an organic pigment having in the molecule thereof a group dissociative under alkaline conditions, an alkaline solvent is used, and in the case of an organic pigment having no group dissociative under alkaline conditions but having in the molecule thereof many nitrogen atoms, to which protons easily adhere, an acidic solvent is used. For example, quinacridone-, diketopyrrolopyrrole-, and condensed disazo-compound pigments are dissolved in alkaline conditions, while phthalocyanine-compound pigments are dissolved in acidic conditions. [0078]
Examples of a base that can be used in the case that the organic pigment is dissolved in alkaline solvent, include inorganic bases, such as lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, and barium hydroxide; and organic bases, such as trialkylamine, diazabicycloundecene (DBU), and metal alkoxides. An inorganic base is preferred. [0079]
The amount of the base to be used is not particularly limited, as long as the base in the amount can homogeneously dissolve the pigment. In the case of the inorganic base, the amount thereof is preferably from 1.0 to 30 mole equivalents, more preferably from 1.0 to 25 mole equivalents, and further preferably from 1 to 20 mole equivalents, to the organic pigment. In the case of the organic base, the amount thereof is preferably from 1.0 to 100 mole equivalents, more preferably from 5.0 to 100 mole equivalents, and further preferably from 20 to 100 mole equivalents, to the organic pigment. [0080] Examples of an acid to be used in the case that the organic pigment is dissolved in the acidic solvent, include inorganic acids, such as sulfuric acid, hydrochloric acid, and phosphoric acid; and organic acids, such as acetic acid, trifluoroacetic acid, oxalic acid, methanesulfonic acid, and
trifluoromethanesulfonic acid. Among these, the inorganic acids are preferable, and sulfuric acid is especially preferable.
The amount of the acid to be used is not particularly limited, as long as the acid in the amount can homogenously dissolve the organic pigment. In many cases, the acid is used in a larger or more excessive amount than the base. Regardless the kind of the acid being an inorganic acid or an organic acid, the amount of the acid to be used is preferably from 3 to 500 mole equivalents, more preferably from 10 to 500 mole equivalents, and further preferably from 30 to 200 mole equivalents, to the organic pigment. [0081]
In the case where an alkali or an acid is mixed with the organic solvent and used the mixture as a good solvent for the organic pigment, a solvent having high solubility for the alkali or the acid such as water or a lower alcohol can be added in a slight amount to the organic solvent in order that the alkali or the acid may be completely dissolved. The amount of water or the lower alcohol is preferably 50 mass% or less, or more preferably 30 mass% or less with respect to the total amount of the organic pigment solution. Specific examples thereof that can be used include water, methanol, ethanol, n-propanol, isopropanol, and butyl alcohol. [0082]
The condition for the poor solvent at the time of depositing the organic pigments is not particularly restricted, and can be selected from a range from a normal pressure condition to a subcritical or supercritical condition. The temperature at which the organic particles are deposited under normal pressure is preferably -30 to 100 °C, more preferably -10 to 60 0 C, and particularly preferably 0 to 30 0 C. The viscosity of the liquid containing precipitated pigment fine particles is preferably in the range of from 0.5 to 80.0 mPa s, and more preferably from 1.0 to 50.0 mPa-s.
At the time of mixing an organic pigment solution and a poor solvent, either of them may be added to the other to mix them. However, it is preferred that mixing is conducted by adding the organic pigment solution to the poor solvent; and it is also preferred that the poor solvent be in a state of being stirred at the time of mixing. The stirring rate is preferably 100 to 10,000 rpm, more preferably 150 to 8,000 rpm, and particularly preferably 200 to 6,000 rpm. A pump or the like may be or may not be used for adding. As the adding method, a method of adding a liquid inside the other liquid or a method of adding a liquid outside the other liquid may be used; a method of adding a liquid inside the other liquid is preferable. In the present invention, it is preferred that one of the liquids be successively fed from inside of the other liquid through a feed pipe using a pump. The inner diameter of the feed pipe is preferably in the range of from 0.1 mm to 200 mm, and more preferably from 0.2 mm to 100 mm. The speed fed from the feed pipe into the other liquid is preferably in the range of from 1 to 10,000 ml/min, and more preferably from 5 to 5,000 ml/min. The mixing ratio of the organic pigment solution and the poor solvent (a ratio of good solvent/poor solvent in the liquid containing precipitated pigment fine particles) is preferably in a range of from 1/50 to 2/3, more preferably from 1/40 to 1/2, and especially preferably from 1/20 to 3/8, in terms of volume ratio.
The pigment concentration in the liquid containing precipitated pigment fine particles is not particularly limited, as long as organic particles can be prepared, but the amount of the organic particles is preferably 10 to 40,000 mg, more preferably 20 to 30,000 mg, and particularly preferably 50 to 25,000 mg, per 1,000 ml of the dispersion solvent.
There is no particular limitation to the scale of preparation at the time when the pigment fine particles are prepared. However, it is preferred that the preparation scale is such that the amount of the poor solvent to be mixed is preferably from 10 to 2,000 L, and more preferably from 50 to 1,000 L. [0083] As to the particle diameter of organic particles, an average scale of a group can be digitalized by several measurement methods. There are frequently-used parameters such as mode diameter indicating the maximum value of distribution, median diameter corresponding to the median value in the integral frequency distribution curve, and various average diameters (number-averaged, length-averaged, area- averaged, weight-averaged diameters, volume-averaged diameters, or the like), and the like. In the present specification, the particle diameter means a number-averaged diameter, unless otherwise particularly specified. The particle diameter of the pigment fine particles (primary particles) is preferably 1 nm to 1 μm, more preferably 1 to 100 nm, further preferably 5 to 80 nm, and particularly preferably 5 to 50 nm. The organic particles may be crystalline particles, amorphous particles, or a mixture of these particles, or in a state of a solid solution. Also preferred are a case where two or more kinds of organic particles coexist, with forming a mixture or a solid solution; and a case where organic particles have a so-called core/shell type structure, in which, on the surface of particle, a layer comprised of another substance is uniformly formed.
Further, in the present invention, a ratio (Mv/Mn) of volume-averaged diameter (Mv) to number- averaged diameter (Mn) is used as the indicator of the monodispersity of particles (degree of the uniformity in particle size), unless otherwise particularly specified. The monodispersity, the ratio Mv/Mn, of the pigment fine particles (primary particles) is preferably 1.0 to 2.0, more preferably 1.0 to 1.8, and particularly preferably 1.0 to 1.5.
Examples of a method of measuring the particle diameter of organic particle include a microscopic method, a gravimetric method, a light scattering method, a light shielding method, an electric resistance method, an acoustic method, and a dynamic light scattering method. Of these, the microscopic method and the dynamic light scattering method are particularly preferable. Examples of a microscope to be used in the microscopic method include a scanning electron microscope and a transmission electron microscope. Examples of a particle measuring device according to the dynamic light scattering method include Nanotrac UPA-EX 150 (trade name) manufactured by NIKKISO Co., Ltd., and a dynamic light scattering photometer DLS-7000 series (trade name) manufactured by OTSUKA ELECTRONICS CO., LTD. [0084]
When a dispersion of the pigment fine particles is prepared, a dispersing agent is preferably incorporated therein. There is no particular limitation imposed on the step of incorporating the dispersing agent, but it is preferred to add the dispersing agent to both or any one of the organic pigment solution and the poor solvent. Further, it is also preferred to add a dispersing agent solution in a route separate from the above-described two solutions at the time when the pigment fine particles are prepared. Besides, it is also preferred to use pigment fine particles that have been previously surface-processed with a dispersing agent; the pigment particles may be subjected to a surface treatment capable of promoting adsorption of the dispersing agent onto the pigment particles. The dispersing agent has functions (1) that the dispersing agent is rapidly adsorbed on the surface of the precipitated pigment, to form fine nanoparticles, and (2) that the dispersing agent prevents these particles from aggregating again.
[0085]
As the dispersing agent, use can be made of an anionic, cationic, amphoteric, nonionic or pigment-derivative-type, and low-molecular-weight or polymer dispersing agent. The molecular weight of the polymer dispersing agent for use may be any value, as long as the dispersing agent can be uniformly dissolved in a solution, but the polymer dispersing agent preferably has a molecular weight of 1 ,000 to 2,000,000, more preferably of 5,000 to 1 ,000,000, still more preferably of 10,000 to 500,000, and particularly preferably of 10,000 to 100,000. Examples of the polymer dispersing agent include polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl methyl ether, polyethylene oxide, polyethylene glycol, polypropylene glycol, polyacrylamide, vinyl alcohol/vinyl acetate copolymer, partial-formal products of polyvinyl alcohol, partial-butyral products of polyvinyl alcohol, vinylpyrrolidone/vinyl acetate copolymer, polyethylene oxide/propylene oxide block copolymer, polyacrylic acid salts, polyvinyl sulfuric acid salts, poly(4-vinylpyridine) salts, polyamides, polyallylamine salts, condensed naphthalenesulfonic acid salts, cellulose derivatives, and starch derivatives. Besides, natural polymers can be used, examples of which include alginic acid salts, gelatin, albumin, casein, gum arabic, tragacanth gum, and ligninsulfonic acid salts. Above all, it is preferred to use any of the aforementioned water-soluble polymers, and it is more preferred to use polyvinyl pyrrolidone. These polymers may be used singly or in combination of two or more. These dispersing agents may be used singly or in combination of two or more thereof. The dispersing agents to be used when dispersing a pigment are described in detail in "Dispersion Stabilization of Pigment and Surface Treatment Technique/Evaluation" (published by Japan Association for International Chemical Information, on December 2001), pp. 29-46. [0086]
Examples of the anionic dispersing agent (anionic surfactant) include N-acyl-N-alkyltaurine salts, fatty acid salts, alkylsulfates, alkylbenzenesulfonates, alkylnaphthalenesulfonates, dialkylsulfosuccinates, alkylphosphates, naphthalenesulfonic acid/formalin condensates, and polyoxyethylenealkylsulfates. N- acyl-N-alkyltaurine salts are particularly preferable. As the N-acyl-N-alkyltaurine salts, those described in JP-A-3-273067 are preferable. These anionic dispersing agents may be used singly or in combination of two or more thereof. [0087]
Examples of the cationic dispersing agent (cationic surfactant) include quaternary ammonium salts, alkoxylated polyamines, aliphatic amine polyglycol ethers, aliphatic amines, diamines and polyamines derived from aliphatic amine and aliphatic alcohol; imidazolines derived from aliphatic acid, and salts of these cationic substances. These cationic dispersing agents may be used singly or in combination of two or more thereof. [0088] The amphoteric dispersing agent is a dispersing agent having, in the molecule thereof, an anionic group moiety which the anionic dispersing agent has in the molecule and a cationic group moiety which the cationic dispersing agent has in the molecule.
Examples of the nonionic dispersing agents (nonionic surfactant) include polyoxyethylenealkyl ethers, polyoxyethylenealkylaryl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylenesorbitan fatty acid esters, polyoxyethylenealkylamines, and glycerin fatty acid esters.
Among these, polyoxyethylenealkylaryl ethers are preferable. These nonionic dispersing agents may be used singly or in combination of two or more thereof.
[0089]
The pigment-derivative-type dispersing agent is defined as a dispersing agent that is derived from an organic pigment as a parent material and prepared by chemically modifying a structure of the parent material or that is obtained by a pigment-forming reaction of a chemically-modified pigment precursor. Examples of the pigment-derivative-type dispersing agent include sugar-containing pigment-derivative-type dispersing agents, piperidyl-containing pigment-derivative-type dispersing agents, naphthalene- or perylene-derivative pigment-derivative-type dispersing agents, pigment-derivative-type dispersing agents having a functional group linked through a methylene group to a pigment parent structure, pigment- derivative-type dispersing agents (parent structure) chemically modified with a polymer, pigment- derivative-type dispersing agents having a sulfonic acid group, pigment-derivative-type dispersing agents having a sulfonamido group, pigment-derivative-type dispersing agents having an ether group, and pigment-derivative-type dispersing agents having a carboxylic acid group, carboxylic acid ester group, or carboxamido group. [0090] When a solution of the organic pigment dissolved in the good solvent is prepared, it is preferred that a pigment dispersing agent containing an amino group coexists with the organic pigment. The term "amino group" described herein embraces a primary amino group, a secondary amino group, and a tertiary amino group. The number of the amino group may be one or plural. The pigment dispersing agent containing an amino group may be a pigment derivative compound wherein a substituent having an amino group is introduced to the skeleton of the pigment, or may be a polymer compound polymerized using a monomer having an amino group as a polymerization component. Examples of these compounds include compounds described in publications of JP-A-2000-239554, JP- A-2003 -96329, JP-A-2001-31885, JP-A-10- 339949, and JP-B-5-72943. However, the present invention is not limited to these compounds. [0091] As the above-described dispersing agent, it is preferred to use at least one compound selected from compounds represented by formulae (Dl), (D3), or (D4) set forth below. <1. Compound represented by formula (Dl)> [0092] [Chemical formula 1]
[0093]
In formula (Dl), A represents a component capable of forming an azo dye together with X-Y. The component A can be arbitrarily selected as long as the component is capable of forming an azo dye upon coupling with a diazonium compound. Specific examples of the component A are shown below, but the present invention is not limited to these compounds. [0094] [Chemical formula 2]
[0095] [Chemical formula 3]
[0096]
In formula (Dl), X represents a single bond, or a group selected from divalent connecting groups represented by structural formulae of formulae (i) to (v) set forth below. [0097] [Chemical formula 4]
[0098]
In formula (Dl), Y represents a group represented by the following formula (D2).
[0099] [Chemical formula 5]
[0100] In formula (D2), Z represents a lower alkylene group. In other words, Z can be expressed as
-(CH 2 ) b - wherein b represents an integer of from 1 to 5, and preferably 2 or 3. In formula (D2), -NR 2I represents a lower alkylamino group, or a nitrogen-containing, 5- or 6-membered, saturated heterocyclic group. In the case where said -NR 21 represents a lower alkylamino group, the lower alkylamino group can be expressed as -N(C r H 2r+ i) 2 wherein r represents an integer of from 1 to 4, and preferably 1 or 2. In the case where said -NR 21 represents a nitrogen-containing, 5- or 6-membered, saturated heterocyclic group, the heterocyclic group is preferably any one of the heterocyclic groups shown by the following structural formulae. [0101] [Chemical formula 6]
[0102]
Each of Z and -NR 2 ] in the above-described formula (D2) may optionally have a lower alkyl group or an alkoxy group, as a substituent. In the above-described formula (D2), a represents 1 or 2, and preferably 2. [0103]
Specific examples of the compound represented by formula (Dl) are shown below, but the present invention is not limited to these examples. [0104] [Chemical formula 7]
[0105] [Chemical formula 8]
[0106] [Chemical formula 9]
[0107] [Chemical formula 10]
[0108]
The compound represented by formula (D 1 ) can be synthesized by the method described in, for example, JP-A-2000-239554. [0109] <2. Compound represented by formula (D3)>
[01 10] [Chemical formula 1 1]
[0111]
In formula (D3), Q represents a residue of an organic dye selected from anthraquinone compound dyes, azo compound dyes, phthalocyanine compound dyes, quinacridone compound dyes, dioxazine compound dyes, anthrapyrimidine compound dyes, anthanthrone compound dyes, indanthrone compound dyes, flavanthrone compound dyes, pyranthrone compound dyes, perynone compound dyes, perylene compound dyes, and thioindigo compound dyes. Among these organic dyes, preferred are azo compound dyes and dioxazine compound dyes. The azo compound dyes are more preferred.
X 1 represents -CO-, -CONH-Y 2 -, -SO 2 NH-Y 2 -, or -CH 2 NHCOCH 2 NH-Y 2 -. X 1 is preferably -CO- or -CONH-Y 2 -.
Y 2 represents an alkylene group or an arylene group, each of which may be substituted. Among these groups, preferred are a phenylene group, a toluilene group, and a hexylene group. The phenylene group is more preferred.
R 11 and R 12 each independently represent a substituted or unsubstituted alkyl group, alternatively, R n and R 12 may be bonded together to form a heterocyclic group which at least contains a nitrogen atom. Among these groups, preferred are a methyl group, an ethyl group, a propyl group, and a pyrrolidinyl group which contains a nitrogen atom. The ethyl group is more preferred.
Yi represents -NH- or -O-.
Zi represents a hydroxyl group or a group represented by formula (D3a) with the proviso that in the case where nl is 1, Z x may be -NH-X 1 -Q. ml represents an integer of 1 to 6, and preferably 2 or 3. nl represents an integer of 1 to 4, and preferably 1 or 2. [0112] [Chemical formula 12]
[0113]
In formula (D3a), Y 3 represents -NH- or -O-, and ml, R 1 ,, and R 12 have the same meanings as those in formula (D3). [0114]
The compounds represented by formula (D3) are specifically represented, for example, by the following formulae. [01 15] [Chemical formula 13]
[01 16]
In formulas (D3-1) to (D3-6), Q, ml, nl , R 11 , and Ri 2 have the same meanings as those in formula (D3). Specific examples of the compound represented by formula (D3) are shown below, but the present invention is not meant to be limited to these. In the following, Cu-Pc represents cupper phthalocyanine. [01 17] [Chemical formula 14]
[0118] [Chemical formula 15]
[0119]
The compounds represented by formula (D3) can be obtained, for example, by reaction of a dye compound with an intermediate which is obtained by a reaction of a halogenated triazine compound with an amine compound having Rn and R 12 and an alcohol compound having R n and R 12 . The disclosure of the specification of JP-B-5-72943 can be also referred for the synthesis of the compound. [0120] <3. Pigment dispersing agent containing graft copolymer>
In the preparation of the above-described pigment fine particles by deposition, it is also preferred to use a dispersing agent containing a graft copolymer having an amino group and an ether group and also, if necessary, containing properly selected other component(s).
The above-described graft copolymer at least has an amino group and an ether group, and also may contain other monomers as a copolymer unit.
The weight-average molecular weight of the graft copolymer is preferably in a range of from 3,000 to 100,000, and more preferably in a range of from 5,000 to 50,000. If the weight-average molecular weight is too small, it is difficult to prevent the pigment fine particles from aggregating, which sometimes results in elevation of viscosity. If the weight-average molecular weight is too large, solubility to an organic solvent becomes insufficient, which sometimes results in elevation of viscosity. [0121]
It is preferred that the above-described graft copolymer contain as copolymer units, at least (i) a polymerizable oligomer having an ethylenically unsaturated double bond at a terminal, (ii) a monomer having an amino group and an ethylenically unsaturated double bond, and (iii) a polymerizable monomer having an ether group, and also, if necessary, contain (iv) other monomer(s). [0122]
The content of each of the copolymer units in the graft copolymer is as follows: the content of (i) the polymerizable oligomer is preferably in the range of from 15 to 98 mass%, more preferably from 25 to 90 mass%, the content of (ii) the amino-group-containing monomer is preferably in the range of from 1 to 40 mass%, more preferably from 5 to 30 mass%, and the content of (iii) the polymerizable monomer having an ether group is preferably in the range of from 1 to 70 mass%, more preferably from 5 to 60 mass%. [0123] If the content of the polymerizable oligomer is too small, a stereo-repulsion effect that should be attained by a dispersing agent is hardly obtained, and it sometimes becomes difficult to prevent the pigment fine particles from aggregating. If the content of the polymerizable oligomer is too large, the ratio of the amino-group-containing monomer relatively decreases so that adsorption capacity to organic particles is lowered, and dispersibility sometimes becomes insufficient. If the content of the amino-group-containing monomer is too small, dispersibility sometimes becomes insufficient owing to reduction of the adsorption capacity to organic particles. If the content of the amino-group-containing monomer is too large, the ratio of the polymerizable oligomer relatively decreases so that a stereo-repulsion effect that should be attained by a dispersing agent is hardly obtained, and it sometimes becomes difficult to sufficiently prevent the pigment fine particles from aggregating. If the content of the polymerizable monomer having an ether group is too small, development suitability at the time of production of color filters and the like sometimes become insufficient. If the content of the polymerizable monomer having an ether group is too large, a capacity as a dispersing agent sometimes reduces. [0124] (i) Polymerizable oligomer The polymerizable oligomer (hereinafter, sometimes also referred to as "macro monomer") has a group having an ethylenically unsaturated double bond at one or both ends (terminals) thereof. Among the aforementioned polymerizable oligomers, it is preferred in the present invention that the oligomer have a group having an ethylenically unsaturated double bond at only one of the ends of the oligomer. [0125] As the aforementioned oligomer, homopolymers or copolymers formed from at least one monomer selected from such monomers as alkyl (meth)acrylates, hydroxyalkyl (meth)acrylates, styrene, acrylonitrile, vinyl acetate, and butadiene can be mentioned. Among these oligomers, preferred are
homopolymers or copolymers of alky 1 (meth)acrylates and polystyrene. In the present invention, these oligomers may further be substituted. There is no particular limitation to the substituent; a halogen atom can be mentioned as an example of the substituent. [0126] Examples of the group having an ethylenically unsaturated double bond include a (meth)acryloyl group and a vinyl group. Among these groups, (meth)acryloyl group is especially preferred. [0127]
Among these polymerizable oligomers for use in the present invention, preferred are oligomers represented by formula (E6) set forth below. [0128]
[Chemical formula 16]
[0129]
In the above-described formula (E6), R 61 and R 63 each represents a hydroxyl group or a methyl group. R 62 represents an alkylene group which has 1 to 8 carbon atoms and which may be substituted by an alcoholic hydroxyl group, and R 62 preferably represents an alkylene group having 2 to 4 carbon atoms. Y 6 represents a phenyl group, a phenyl group having an alkyl group having 1 to 4 carbon atoms, or -COOR 64 (R 64 represents an alkyl group which has 1 to 6 carbon atoms and which may be substituted by an alcoholic hydroxyl group or halogen atom; a phenyl group, or an aralkyl group having 7 to 10 carbon atoms); and Y 6 preferably represents a phenyl group or -COOR 164 (R 164 represents an alkyl group which has 1 to 4 carbon atoms and which may be substituted with an alcoholic hydroxyl group), q represents a number of from 20 to 200. [0130]
Specific examples of the polymerizable oligomer include poly-2-hydroxyethyl (meth)acrylate, polystyrene, poly-methyl (meth)acrylate, poly-n-butyl (meth)acrylate, poly-i-butyl (meth)acrylate, and copolymers of these monomers. Among these polymers, preferred are polymers having a (meth)acryloyl group bonded to one terminal of the molecule.
[0131]
The polymerizable oligomer may be a commercially available product, or may be appropriately synthesized. Examples of the commercially available product include: a single-terminal-methacryloylated polystyrene oligomer (Mn = 6,000, trade name: AS-6, manufactured by TOAGOSEI CO., LTD.); a single- terminal-methacryloylated polymethyl methacrylate oligomer (Mn = 6,000, trade name: AA-6, manufactured by TOAGOSEI CO., LTD.); a single-terminal-methacryloylated poly-n-butyl acrylate oligomer (Mn = 6,000, trade name: AB-6, manufactured by TOAGOSEI CO., LTD.); a single-terminal- methacryloylated polymethyl methacryIate/2-hydroxyethyl methacrylate oligomer (Mn = 7,000, trade name: AA-714, manufactured by TOAGOSEI CO., LTD.); a single-terminal-methacryloylated polybutyl methacrylate/2-hydroxyethyl methacrylate oligomer (Mn = 7,000, trade name: 707 S, manufactured by TOAGOSEI CO., LTD.); and a single-terminal-methacryloylated poly-2-ethylhexyl methacrylate/2- hydroxyethyl methacrylate oligomer (Mn = 7,000, trade name: AY-707 S or AY-714 S, manufactured by
TOAGOSEI CO, LTD.). [0132]
A preferable specific example of the polymerizable oligomer in the present invention is at least one kind of an oligomer selected from a polymer of an alkyl (meth)acrylate and a copolymer of an alkyl (meth)acrylate and polystyrene, with the oligomer having a number average molecular weight of 1 ,000 to 20,000, and with the oligomer having a (meth)acryloyl group at a terminal.
[0133] (ii) Amino-group-containing monomer
As the amino-group-containing monomer, a preferable example is any one of the compounds represented by formula (E2) set forth below. [0134] [Chemical formula 17]
[0135] In the above-described formula (E2), R 21 represents a hydroxyl group or a methyl group. R 22 represents an alkylene group having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms, and especially preferably 2 to 3 carbon atoms
[0136]
X 2 represents -N(R 23 )(R 24 ), or -R 25 N(R 26 )(R 27 ), wherein R 23 and R 24 each represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, and R 25 represents an alkylene group having 1 to 6 carbon atoms, and R 26 and R 27 each represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group.
[0137]
R 23 and R 24 of the -N(R 23 )(R 24 ) are preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group, and R 25 of the -R 25 N(R 26 )(R 27 ) is preferably an alkylene group having 2 to
6 carbon atoms, and R 26 and R 27 are preferably an alkyl group having 1 to 4 carbon atoms. m2 and n2 each represent 1 or 0. The cases where m2 = 1 and n2 = 1 and where m2 = 1 and n2 = 0 are preferred.
(The resultant monomers correspond to the monomers represented by formulae (E3) and (E4) set forth below.) [0138]
In the present invention, among the monomers represented by formula (E2), preferred are at least one monomer selected from the monomers represented by formula (E3) or (E4) set forth below.
[0139] [Chemical formula 18]
[0140]
In the above-described formula (E3), R 31 has the same meaning as R 21 . R 32 has the same meaning as R 22 . X 3 has the same meaning as X 2 . [0141] [Chemical formula 19]
[0142]
In the above-described formula (E4), R 41 has the same meaning as R 21 . X 4 has the same meaning as X 2 , and X 4 is preferably -N(R 43 XR 44 ) (wherein R 43 and R 44 have the same meanings as R 23 and R 24 ), or -R 45 N(R 46 XR 47 ) (wherein R 45 , R 46 , and R 47 have the same meaning as R 25 , R 26 , and R 27 ). [0143]
Preferable examples of the monomer represented by the above-described formula (E2) include (meth)acrylamides such as dimethyl (meth)acrylamide, diethyl(meth)acrylamide, diisopropyl(meth)acrylamide, di-n-butyl(meth)acrylamide, di-i-butyl(meth)acrylamide, morpholino(meth)acrylamide, piperidino(meth)acrylamide, N-methyl-2-pyrrolidyl(meth)acrylamide, and N,N-methylphenyl(meth)acrylamide; and aminoalkyl(meth)acrylamides such as 2-(N,N- dimethylamino)ethyl (meth)acrylamide, 2-(N,N-diethylamino)ethyl(meth)acrylamide, 3-(N,N- diethylamino)propyl(meth)acrylamide, 3-(N,N-dimethylamino) propyl(meth)acrylamide, 1-((N,N- dimethylamino)- 1 , 1 -dimethy lmethyl(meth)acrylamide, and 6-(N,N-diethylamino)hexyl(meth)acrylamide. [0144] (iii) Polymerizable monomer having ether group
As the polymerizable monomer having an ether group, preferred are at least one monomer selected from the monomers represented by formula (E 1 ) set forth below. [0145] [Chemical formula 20]
[0146]
In the above formula (El), R" represents a hydrogen atom or a methyl group. R 12 represents an alkylene group having 1 to 8 carbon atoms, preferably an alkylene group having 1 to 6 carbon atoms, and more preferably an alkylene group having 2 to 3 carbon atoms. X 1 represents -OR 13 or -OCOR 14 . Wherein, R 13 represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, a phenyl group, or a phenyl group substituted with an alkyl group having 1 to 18 carbon atoms. R 14 represents an alkyl group having 1 to 18 carbon atoms. Also, m3 denotes a number of 2 to 200, preferably 5 to 100, and particularly preferably 10 to 100.
[0147]
No particular restriction is imposed on the polymerizable monomer having an ether group as long as the monomer is polymerizable and has an ether group, and the monomer can be appropriately selected from conventional known monomers. Examples thereof include polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, polyethylene glycol polypropylene glycol mono(meth)acrylate, and polytetramethylene glycol monomethacrylate. These materials may be commercially available products or may be those synthesized properly. Examples of these commercially available products include methoxypolyethylene glycol methacrylate (trade name: NK ESTER M-40G, M-90G, and M-230G (manufactured by Toagosei Co., Ltd.); trade name: BLENMER-PME- 100, PME-200, PME-400, PME-1000, PME-2000, and PME-4000 (manufactured by Nippon Oil & Fats Co., Ltd.)), polyethylene glycol monomethacrylate (trade name: BLENMER-PE-90, PE-200, and PE-350 (manufactured by Nippon Oil & Fats Co., Ltd.)); polypropylene glycol monomethacrylate (trade name: BLENMER-PP-500, PP-800, and PP-1000 (manufactured by Nippon Oil & Fats Co., Ltd.)), polyethylene glycol polypropylene glycol monomethacrylate (trade name: BLENMER-70PEP-370B (manufactured by Nippon Oil & Fats Co., Ltd.)), polyethylene glycol polytetramethylene glycol monomethacrylate (trade name: BLENMER-55PET-800 (manufactured by Nippon Oil & Fats Co., Ltd.)), and polypropylene glycol polytetramethylene glycol monomethacrylate (trade name: BLENMER-NHK-5050 (manufactured by Nippon Oil & Fats Co., Ltd.)). [0148] (iv) Other monomers The above-described graft copolymers may contain, additionally, the above-described other monomer(s) as a copolymer unit. The other monomers are not particularly limited, and they can be properly selected in accordance with purposes. Examples of the other monomers include aromatic vinyl compounds (e.g., styrene, α-methyl styrene, vinyl toluene), alkyl (meth)acrylates (e.g., methyl(meth)acrylate, ethyl(meth)acrylate, n-butyl(meth)acrylate, i-butyl(meth)acrylate), alkylaryl(meth)acrylates (e.g., benzyl(meth)acrylate), glycidyl(meth)acrylate, vinyl carboxylates (e.g., vinyl acetate, vinyl propionate), vinyl cyanides (e.g., (meth)acrylonitrile, α-chloro acrylonitrile), aliphatic conjugate dienes (e.g., 1 ,3-butadiene, isoprene), and (meth)acrylic acid. Among these monomers, preferred are unsaturated carboxylic acids, alkyl(meth)acrylates, alkylaryl(meth)acrylates, and vinyl carboxylates. [0149]
The content of the other monomers in the above-described graft copolymers is, for example, preferably in the range of from 5 to 70 mass%. If the content is too small, it sometimes becomes difficult to control physical properties of the coating film. If the content is too large, it sometimes becomes difficult for the graft copolymer to fully exhibit its capacity as a dispersing agent. [0150]
Preferable specific examples of the graft copolymers include:
(11 ) A copolymer of 3-(N,N-dimethylamino)propylacrylamide/polyethyleneglycol mono(meth)acrylate/terminal-methacryloylated polymethyl (meth)acrylate,
(12) A copolymer of 3-(N,N-dimethylamino)propylacrylamide/polyethyleneglycol mono(meth)acrylate/terminal-methacryloylated polystyrene,
[0151]
(13) A copolymer of 3-(N,N-dimethytamino)propylacrylamide/polyethyleneglycol
mono(meth)acrylate/methyl (meth)acrylate/terminal-methacryloylated polystyrene, (14) A copolymer of 3-(N,N-dimethylamino)propylacrylamide/polyethyleneglycol mono(meth)acrylate/a copolymer of terminal-methacryloylated methyl (meth)acrylate and 2-hydroxyethylmethacrylate, [0152] ( 17) A copolymer of 3-(N,N-dimethylamino)propylacrylamide/polypropyleneglycol mono(meth)acrylate/terminal-methacryloylated polymethyl (meth)acrylate,
(18) A copolymer of 3-(N,N-dimethylarnino)propylacrylamide/polyethyleneglycol polypropyleneglycol mono (meth)acrylate/terminal-methacryloylated polymethyl (meth)acrylate,
(19) A copolymer of 3-(N,N-dimethylamino)propylacrylamide/polyethyleneglycol polytetramethyleneglycol mono (meth)acrylate/terminal-methacryloylated polymethyl (meth)acrylate,
(20) A copolymer of 3-(N,N-dimethylamino)propylacrylamide/polypropyleneglycol polytetramethyleneglycol mono (meth)acrylate/terminal-methacryloylated polymethyl (meth)acrylate.
Among these copolymers, preferred are (11), (14), and (18). More preferred is a compound represented by formula (D4) set forth below. In formula (D4), Me represents a methyl group. [0153]
[Chemical formula 21 ]
[0154]
The above-described graft copolymers can be obtained by subjecting components that constitute units of the above-described copolymers to, for example, radical polymerization in a solvent. At the time of the radical polymerization, a radical polymerization initiator may be used. Further, there can be used a chain transfer agent (e.g., 2-mercapto ethanol and dodecyl mercaptan). A pigment dispersing agent containing a graft copolymer can be also prepared with reference to descriptions of JP-A-2001-31885. [0155] In order to further improve uniform dispersibility and preservability of pigment fine particles, the content of the dispersing agent is preferably in the range of from 0.1 to 1000 mass parts, more preferably from 1 to 500 mass parts, and furthermore preferably from 5 to 20 mass parts, based on 100 mass parts of the pigment. A too-small content sometimes results in no improvement in dispersion stability of the pigment fine particles. The dispersing agent may be used singly or in combination of plural dispersing agents. [0156]
In order to further improve uniform dispersibility and preservability of organic particles, the content of the dispersing agent is preferably in the range of from 0.1 to 1000 mass parts, more preferably from 1 to 500 mass parts, and furthermore preferably from 5 to 20 mass parts, based on 100 mass parts of the organic particles. A too-small content sometimes results in no improvement in dispersion stability of the organic particles. The dispersing agent may be used singly or in combination of plural dispersing
agents. [0157] (Concentration)
The pigment fine particle dispersion may be subjected to desalting and condensation, whereby a concentrated liquid suitable for a color filter coating liquid or for inkjet ink can be produced on an industrial scale.
The condensation method is not particularly restricted as long as the pigment fine particle liquid can be concentrated by the method. Examples of a preferable condensation method include: a method involving adding and mixing an extraction solvent to and with a pigment fine particle dispersion, condensing and extracting the pigment fine particles to the extraction solvent phase, and filtering the concentrated extract liquid through a filter or the like, to provide a concentrated nanoparticles liquid; a method involving sedimenting the pigment fine particles by centrifugal separation for condensation; a method involving performing desalting and condensation by ultrafiltration; a method involving sublimating a solvent by vacuum freeze-drying for condensation; and a method involving drying a solvent under heat or reduced pressure for condensation. Alternatively, a combination of two or more of these methods is extremely preferably employed.
The pigment fine particle concentration after condensation is preferably 1 to 100 mass%, more preferably 5 to 100 mass%, and particularly preferably 10 to 100 mass%. [0158] The extraction solvent for use in the process of concentrating and extracting is not particularly limited, but it is preferably a solvent that is substantially incompatible (immiscible) with the dispersion solvent of the pigment fine particle dispersion (e.g., aqueous solvent) (in the present specification, the term "substantially incompatible" means that the compatibility is low, and the amount of the extraction solvent soluble in the dispersion solvent is preferably 50 mass% or less, and more preferably 30 mass% or less; although the amount of the extraction solvent soluble in the dispersion solvent has no particular lower limit, it is practical that the amount is 1 mass% or more in consideration of the solubility in an ordinary solvent), and that forms an interface after the extraction solvent is mixed with the dispersion solvent and left still. In addition, the extraction solvent is preferably a solvent that causes weak aggregation to such a degree that the pigment fine particles can be redispersed in the extraction solvent. Herein, "weak, redispersible aggregation" means a floe that can be redispersed without applying high shearing force such as by milling or high-speed agitation. Such a state is preferable, because it is possible to prevent strong aggregation that may change the particle size, and to swell the desirable pigment fine particles with the extraction solvent, besides the dispersion solvent such as water can be easily and rapidly removed by filter-filtration. As the extraction solvent, ester compound solvents, alcohol compound solvents, aromatic compound solvents, and aliphatic compound solvents are preferable; ester compound solvents, aromatic compound solvents, and aliphatic compound solvents are more preferable; and ester compound solvents are particularly preferable. [0159]
Examples of the ester compound solvent include 2-(l-methoxy)propyl acetate, ethyl acetate, ethyl lactate, and the like. Examples of the alcohol compound solvent include n-butanol, isobutanol, and the like. Examples of the aromatic compound solvent include benzene, toluene, xylene, and the like.
Examples of the aliphatic compound solvent include n-hexane, cyclohexane, and the like. The extraction solvent may be a pure solvent of one of the preferable solvents above, while it may be a mixed solvent of
multiple solvents. [0160]
The amount of the extraction solvent is not particularly limited, as long as the solvent can extract the pigment fine particles, but the amount of the extraction solvent is preferably smaller than the amount of the pigment fine particle dispersion, considering extraction for concentration. If expressed by volume ratio, the amount of the extraction solvent to be added is preferably in the range of 1 to 100, more preferably in the range of 10 to 90, and particularly preferably in the range of 20 to 80, with respect to 100 of the pigment fine particle dispersion. A too-large amount may results in elongation of the period for concentration, while a too-small amount may cause insufficient extraction and residual nanoparticles in the dispersion solvent.
After addition of the extraction solvent, it is preferably agitated well for sufficient mutual contact with the dispersion. Any conventional method may be used for agitation and mixing. The temperature during addition and mixing of the extraction solvent is not particularly limited, but preferably 1 to 100 0 C and more preferably 5 to 60 0 C. Any apparatus may be used for addition and mixing of the extraction solvent as long as it can suitably carry out each step. For example, a separatory funnel-like apparatus may be used. [0161]
As the method for ultrafiltration, methods used for desalting and concentrating silver halide emulsion can be used. Examples are those methods described in Research Disclosure, No. 10208 (1972), No. 13 122 (1975), No. 16 351 (1977) etc. While pressure difference and flow rate, which are important as the operational conditions, can be selected by referring to the characteristic curves mentioned in Haruhiko Oya, "Maku Riyo Gijutsu Handbook (Membrane Utilization Technique Handbook)", published by Saiwai Shobo (1978), p. 275, it is necessary to find out optimum conditions for treating a pigment fine particle dispersion composition of interest in order to suppress aggregation of particles. As a method for supplementing the solvent lost due to passage through the membrane, there are the constant volume method - • where the solvent is continuously supplemented and the batch method where the solvent is intermittently added. The constant volume method is preferred in the present invention because of its relatively shorter desalting treatment time. As the solvent to be supplemented as described above, pure water obtained by ion exchange or distillation is generally used. A dispersing agent or a poor solvent for dispersing agent may be mixed in the pure water. Alternatively, the dispersing agent or the poor solvent for dispersing agent can also be directly added to the pigment fine particle dispersion. [0162]
As an ultrafiltration membrane, modules of plate type, spiral type, cylinder type, hollow yarn type, hollow fiber type and so forth, in which a membrane is already incorporated, are commercially available from Asahi Chemical Industry Co., Ltd., Daicel Chemical Industries, Ltd., Toray Industries, Inc., NITTO DENKO CORP. and so forth. In view of the total membrane area and washability, those of hollow yam type and spiral type are preferred. The fractional molecular weight, which is an index of a threshold for substances that can permeate a membrane, must be. determined based on the molecular weight of the used dispersing agent. In the present invention, those having a fractional molecular weight of 5,000 to 50,000, more preferably 5,000 to 15,000, are preferably used. [0163]
To separate a concentrated extract liquid from a dispersion solvent of the pigment fine particle
dispersion, filtration by using a filter is preferable. As the apparatus for filter-filtration, for example, an apparatus such as a high-pressure filtration apparatus can be used. Preferable filters include nanofilter, ultrafilter and the like. It is preferable to remove a residual dispersion solvent by filter filtralation, so as to further concentrate pigment fine particles in the concentrated extract liquid and to obtain a concentrated nanoparticle liquid. [0164]
A method for freeze-drying is not particularly limited, and any method may be adopted as long as a person skilled in the art can utilize the method. Examples of the freeze-drying method include a coolant direct expansion method, a multiple freezing method, a heating medium circulation method, a triple heat exchange method, and an indirect heating freezing method. Of these, the coolant direct-expansion method or the indirect heating freezing method is preferably employed, and the indirect heating freezing method is more preferably employed. In each method, preliminary freezing is preferably performed before freeze- drying is performed. Conditions for freeze-drying are not particularly limited, but a sample to be subjected to freeze-drying must be uniformly frozen. [0165]
Examples of a device for the indirect heating freezing method include a small freeze-drying machine, an FTS freeze-drying machine, an LYOVAC freeze-drying machine, an experimental freeze- drying machine, a research freeze-drying machine, a triple heat exchange vacuum freeze-drying machine, a monocooling-type freeze-drying machine, and an HULL freeze-drying machine. Of these, the small freeze-drying machine, the experimental freeze-drying machine, the research freeze-drying machine, or the monocooling-type freeze-drying machine is preferably used, and the small freeze-drying machine or the monocooling-type freeze-drying machine is more preferably used. [0166]
The temperature for freeze-drying, which is not particularly limited, is, for example, about -190 to -4°C, preferably about -120 to -20 0 C, and more preferably about -80 to -60 0 C. The pressure for freeze- drying is not particularly limited either, and can be appropriately selected by a person skilled in the art. It is recommended that freeze-drying be performed under a pressure of, for example, about 0.1 to 35 Pa, preferably about 1 to 15 Pa, and more preferably about 5 to 10 Pa. The time period for freeze-drying is, for example, about 2 to 48 hours, preferably about 6 to 36 hours, or more preferably about 16 to 26 hours. It should be noted, however, that these conditions can be appropriately selected by a person skilled in the art. With regard to a method for freeze-drying, reference can be made to, for example, Pharmaceutical machinery and engineering handbook by JAPAN SOCIETY OF PHARMACEUTICAL MACHINERY AND ENGINEERING, Chijinshokan Co., Ltd., p. 120-129 (September, 2000), Vacuum handbook by ULVAC, Inc., Ohmsha, Ltd., p. 328-331 (1992), or Freezing and drying workshop paper by Koji Ito et al., No. 15, p. 82 (1965). [0167]
The centrifugal separator for use in the condensation of the pigment fine particles by centrifugal separation may be an arbitrary device as long as the pigment fine particles in the pigment fine particle dispersion (or the pigment fine particles concentrated extract liquid) can be sedimented. Examples of the centrifugal separator include a general-purpose device, a system having a skimming function (function with which a supernatant layer is sucked during the rotation of the system, to discharge to the outside of the system), and a continuous centrifugal separator for continuously discharging solid matter.
As the conditions for centrifugal separation, a centrifugal force (a value representing a ratio of an applied centrifugal acceleration to the gravitational acceleration) is preferably 50 to 10,000, more preferably 100 to 8,000, and particularly preferably 150 to 6,000. The temperature at the time of centrifugal separation is preferably -10 to 8O 0 C, more preferably -5 to 70°C, and particularly preferably 0 to 60 0 C, though a preferable temperature varies depending on the kind of the solvent of the dispersion. [0168]
The device for use in the condensation of the pigment fine particles by drying under reduced pressure is not particularly limited as long as the solvent of the pigment fine particle dispersion (or the pigment fine particles concentrated extract liquid) can be evaporated. Examples of the device include a general-purpose vacuum drier and a general-purpose rotary pump, a device capable of drying a liquid under heat and reduced pressure while stirring the liquid, and a device capable of continuously drying a liquid by passing the liquid through a tube the inside of which is heated and reduced in pressure.
The temperature for drying under heat and reduced pressure is preferably 30 to 230 0 C, more preferably 35 to 200 0 C, or particularly preferably 40 to 180 0 C. The pressure for the above-mentioned reduced pressure is preferably 100 to 100,000 Pa, more preferably 300 to 90,000 Pa, and particularly preferably 500 to 80,000 Pa. [0169]
According to the condensation method as described above, the pigment fine particles can be efficiently concentrated from the pigment fine particle dispersion. The condensation ratio is, for example, as follows: when the concentration of the nanoparticles in the pigment fine particle dispersion serving as a raw material is set to 1, the concentration in a concentrated pigment fine particles paste can be preferably about 100 to 3,000 times, and more preferably about 500 to 2,000 times. [0170] [Fining and dispersing] When pigment fine particles are in the state of aggregation owing to the aforementioned concentration etc, it is preferred to subject the aggregation to fining and dispersing. (In the present specification, the term "fining and dispersing" means a process to release particles in a dispersion from the aggregation state, thereby to enhance degree of dispersion.)
The organic particles contained in an organic particle liquid condensed by the above-described extraction solvent, centrifugal separation, and drying etc. are ordinarily in the state of aggregation owing to condensation of the organic particles. In order to enable a rapid filtration and to obtain an excellent dispersion state again, it is preferred to obtain the aforementioned pigment fine particles as a flock. The flock is an assembly of fine particles weakly aggregate to each other to a degree allowing redispersion (soft- aggregated). By forming the pigment fine particles into a flock, it becomes possible to separate organic pigment fine particles precipitated for example in an aqueous liquid mixture, rapidly from the medium for example by filtration. It is possible to form a pigment dispersion composition dispersed in an organic solvent (nonaqueous dispersion composition) efficiently, by redispersing the separated floe (soft aggregate) in the organic solvent suitable for preparation of color filter. In other words, when the mixed solvent of good and poor solvents is an aqueous solvent, it is possible to efficiently replace the aqueous solvent with a third solvent comprised of an organic solvent, thereby to change the dispersion medium (continuous phase). The average diameter of the floe is not particularly limited, but it is preferably 0.5 to 500 μm, more preferably 5 to 100 μm, considering the filtration efficiency described above. In the present specification,
solvents different from both of the good solvent (first solvent) and the poor solvent (second solvent) are collectively called "third solvents".
With some particles, there is a case where a level of dispersion achieved by an ordinary dispersing method is insufficient for fining the particles and a method that can conduct fining with higher efficiency is necessary. Even such organic particles in a strongly aggregated state can be made into a dispersion, in which the organic particles are properly fined and dispersed, by a method of introducing a polymer compound having a number-average molecular weight of 1,000 or more in the aggregated organic particles liquid. (In the present specification, the term "aggregated organic particles" means an assembly of organic particles gathered together by a secondary force, such as aggregates; in the case of nanometer- sized primary particles, they are also referred to as "aggregated nanoparticles".) (In the present specification, the term "aggregated organic particles liquid" means a liquid containing aggregated organic particles, and the liquid may be, for example, a dispersion, a concentrated liquid, a paste, or slurry as long as the liquid contains the aggregated organic particles.) More specifically, by adding the polymer compound, the favorable fine dispersibility (property giving uniform and fine particle diameter) and the favorable dispersion stability (property maintaining uniform and fine particle diameter for an extended period of time) obtained when precipitated in a liquid mixture of good and poor solvents, are retained consistently even after the medium is changed to an organic solvent suitable for color filter and the fine particles are redispersed in the medium, consequently giving a high-performance color filter. In addition, the polymer compound does not deteriorate the optical properties and other properties of the color filter, and can rather improve the properties of the color filter and the liquid crystal display device, via interaction with coloring property of the organic pigment fine particles. [0171]
As the above-described polymer compound, preferred are polymer compounds represented by formula (1) set forth below. [0172]
[Chemical formula 22]
[0173]
In formula (1), A 1 represents a monovalent organic group having a group selected from the group consisting of an acidic group, a nitrogen-containing basic group, a urea group, a urethane group, a group having a coordinating oxygen atom, a hydrocarbon group having 4 or more carbon atoms, an alkoxy silyl group, an epoxy group, an isocyanate group, and a hydroxyl group, or a monovalent organic group containing an organic dye structure or heterocycle each of which may further be substituted. If n is two or more, plural A 1 S may be the same or different. Specifically, A 1 is not particularly limited. Examples of the "monovalent organic group having an acidic group" include a monovalent organic group having an acid group such as a carboxylic acid group, a sulfonic acid group, a monosulfuric acid ester group, a phosphoric acid group, a monophosphoric acid ester group, and a boric acid. Beside, examples of the "monovalent organic group having a nitrogen- containing basic group" include a monovalent organic group having an amino group (-NH 2 ), a monovalent
organic group having a substituted imino group (-NHR 8 , -NR 9 R 10 ) (wherein R 8 , R 9 , and R 10 each independently represent an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 30 carbon atoms), a monovalent organic group having a guanidyl group represented by the following formula (al) (wherein, in formula (al), R al and R a2 each independently represent an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 30 carbon atoms), and a monovalent organic group having an amidinyl group represented by the following formula (a2) (wherein, in formula (a2), R a3 and R a4 each independently represent an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 30 carbon atoms). [0174]
[Chemical formula 23]
[0175]
Examples of the "monovalent organic group having a urea group" include -NHCONHR 15 (wherein R 15 represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 30 carbon atoms), and the like.
Examples of the "monovalent organic group having a urethane group" include -NHCOOR 16 , -OCONHR 17 (wherein R 16 and R 17 each independently represent an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 30 carbon atoms), and the like.
Examples of the "monovalent organic group having 'a group having a coordinating oxygen atom'" include a group having an acetylacetonato group, a group having crown ether, and the like.
Examples of the "monovalent organic group having a hydrocarbon group having 4 or more carbon atoms" include an alkyl group having 4 or more carbon atoms (e.g., octyl, dodecyl), an aryl group having 6 or more carbon atoms (e.g., phenyl, naphthyl), an aralkyl group having 7 or more carbon atoms (e.g., benzyl), and the like. For the carbon atoms of these groups, there is no specific upper limit; it is, however, preferred that the number of carbon atoms is 30 or less.
Examples of the "monovalent organic group having an alkoxy silyl group" include a group having a trimethoxy silyl group or triethoxy silyl group. Examples of the "monovalent organic group having an epoxy group" include a group having a glycidyl group.
Examples of the "monovalent organic group having an isocyanate group" include a 3- isocyanatopropyl group.
Examples of the "monovalent organic group having a hydroxyl group" include a 3- hydroxypropyl group. [0176]
Among these groups represented by the above-described A 1 , preferred is a monovalent organic group having any one of an acidic group, a nitrogen-containing basic group, a urea group, and a
hydrocarbon group having 4 or more carbon atoms. [0177]
The above-described organic dye structure or heterocycle is not particularly limited. But, more specifically stated, examples of the organic dye structure include phthalocyanine compounds, insoluble azo compounds, azo lake compounds, anthraquinone compounds, quinacridone compounds, dioxazine compounds, diketopyrrolopyrrole compounds, anthrapyridine compounds, anthanthrone compounds, indanthrone compounds, flavanthrone compounds, perynone compounds, perylene compounds, and thioindigo compounds. Examples of the heterocycle include thiophene, furan, xanthene, pyrrole, pyrroline, pyrrolidine, dioxolan, pyrazole, pyrazoline, pyrazolidine, imidazole, oxazole, thiazole, oxadiazole, triazole, thiadiazole, pyran, pyridine, piperidine, dioxane, morpholine, pyridazine, pyrimidine, piperazine, triazine, trithiane, isoindoline, isoindolinone, benzimidazolone, succinimide, phthalimide, naphthalimide, hydantoin, indole, quinoline, carbazole, acridine, acridone, and anthraquinone. [0178]
The above-described organic dye structure or heterocycle may have a substituent T. Examples of the substituent T include an alkyl group having 1 to 20 carbon atoms (e.g., methyl, ethyl), an aryl group having 6 to 16 carbon atoms (e.g., phenyl, naphthyl), an acyloxy group having 1 to 6 carbon atoms (e.g., acetoxy), an alkoxy group having 1 to 6 carbon atoms (e.g., methoxy, ethoxy), a halogen atom (e.g., chlorine, bromine), an alkoxycarbonyl group having 2 to 7 carbon atoms (e.g., methoxycarbonyl, ethoxycarbonyl, cyclohexyloxycarbonyl), a cyano group, a carbonic acid ester group (e.g., t-butylcarbonate), a hydroxyl group, an amino group, a carboxyl group, a sulfonamide group, and N-sulfonylamido group. [0179]
Besides, the above-described A 1 can be represented by the following formula (4). [0180] [Chemical formula 24]
[0181]
In formula (4), B 1 represents a group selected from the group consisting of an acidic group, a nitrogen-containing basic group, a urea group, a urethane group, a group having a coordinating oxygen atom, a hydrocarbon group having 4 or more carbon atoms, an alkoxy silyl group, an epoxy group, an isocyanate group, and a hydroxyl group, or represents an organic dye structure or heterocycle each of which may further be substituted. R 18 represents a single bond, or (al + l)-valent organic or inorganic connecting group, al represents 1 to 5. Herein, in the case where al is two or more, plural B 1 S may be the same or different.
Preferable embodiments of the group represented by formula (4) are the same as the above- described A 1 . [0182]
R 18 represents a single bond, or a (al+l)-valent connecting group, al represents 1 to 5. Examples of the connecting group represented by R 18 include those formed from atoms consisting of from 1 to 100 carbon atoms, from 0 to 10 nitrogen atoms, from 0 to 50 oxygen atoms, from 1 to 200 hydrogen
atoms, and from 0 to 20 sulfur atoms, which groups may be unsubstituted or substituted with a substituent.
R 18 is preferably an organic connecting group.
[0183]
Specific examples of R 18 include structural units set forth below, or a group consisted of a combination of said structural units. In addition, the connecting group R 18 may have the aforementioned substituent T. [0184] [Chemical formula 25]
In the above-described formula (1), R 1 represents a (m+n)-valent connecting group, m+n is within the range of 3 to 10.
Examples of the (m+n)-valent connecting group represented by R 1 include those groups formed from atoms consisting of from 1 to 100 carbon atoms, from 0 to 10 nitrogen atoms, from 0 to 50 oxygen atoms, from 1 to 200 hydrogen atoms, and from 0 to 20 sulfur atoms, which groups may be unsubstituted or substituted with a substituent. R 1 is preferably an organic connecting group. [0186]
Examples of R 1 include the above-described groups of (M) to (t-34) or a group (which may have a ring structure) consisted of a combination of a plurality of said groups. In the case where the above- described connecting group R 1 has a substituent, examples of said substituent include the above-described substituent T.
[0187]
R 2 represents a single bond or a divalent connecting group. Examples of R 2 include groups formed from atoms consisting of from 1 to 100 carbon atoms, from 0 to 10 nitrogen atoms, from 0 to 50 oxygen atoms, from 1 to 200 hydrogen atoms, and from 0 to 20 sulfur atoms, which groups may be unsubstituted or substituted with a substituent. Specific examples of R 2 include the above-described groups of t-3 to t-5, t-7 to t-18, t-22 to t-26, t-32 and t-34, or a group consisted of a combination of a plurality of said groups. It is preferred that R 2 have a sulfur atom at the position where said R 2 connect to R 1 . In the case where R 2 has a substituent, examples of said substituent include the above-described substituent T. [0188]
In the above-described formula (1), m represents 1 to 8. m is preferably 1 to 5, more preferably 1 to 3, and particularly preferably 1 to 2. n represents 2 to 9. n is preferably 2 to 8, more preferably 2 to 7, and particularly preferably 3 to 6. [0189]
In the above-described formula (1), P 1 represents a polymer skeleton. Such the polymer skeleton can be properly selected from ordinary polymers.
In order to form the polymer skeleton, it is preferred to use at least one kind selected from the group consisting of polymers or copolymers derived from a vinyl monomer, ester compound polymers, ether compound polymers, urethane compound polymers, amide compound polymers, epoxy compound polymers, silicone compound polymers, and modified compounds or copolymers of these polymers (e.g. copolymers of polyether/polyurethane, and copolymers of polyether/polymer derived from a vinyl monomer; these copolymers may be any one of a random copolymer, a block copolymer, and a graft copolymer)); more preferred to use at least one kind selected from the group consisting of polymers or copolymers derived from a vinyl monomer, ester compound polymers, ether compound polymers, urethane compound polymers, and modified compounds or copolymers of these polymers; and particularly preferred to use homopolymers or copolymers derived from a vinyl monomer.
Besides, it is preferred that these polymers are soluble in an organic solvent. If the polymer has a low affinity with the organic solvent, affinity of the polymer with a dispersing medium becomes weak in the case where said polymer is used, for example, as a pigment dispersing agent. Consequently, it becomes sometimes difficult to secure an adsorption layer enough for dispersion stabilization. It is preferred that P 1 have a sulfur atom at the position where said P 1 connect to R 1 . [0190]
Of the polymer compounds represented by the above-described formula (1), more preferred are those polymer compounds represented by the formula (2). [0191] [Chemical formula 26]
[0192]
In the above-described formula (2), A 2 has the same meaning as A 1 in the above-described formula (1). Specific and preferable embodiments of A 2 are the same as those of A 1 . A 2 may have a substituent with examples thereof including the above-described substituent T. [0193] In the above-described formula (2), R 3 represents a (x+y)-valent connecting group. R J has the same meaning as R 1 . The preferable range of R 3 is the same as that of R 1 . In this case where R 3 represents a (x+y)-valent connecting group, the value of said x and its preferable range are the same as those of n in formula (1). Similarly, the value of said y and its preferable range are the same as those of m; the value of said x+y and its preferable range are the same as those of m+n. [0194]
The connecting group represented by R 3 is preferably an organic connecting group. Preferred specific examples of the organic connecting groups are set forth below. However, the present invention is not limited to these.
[0195] [Chemical formula 27]
[0196] [Chemical formula 28]
[0197]
Among the above-described connecting groups, preferred are groups of (r-1), (r-2), (r-10), (r-1 1), (r-16), and (r-17), from the viewpoints of availability of raw materials, easiness of synthesis, and solubility in various solvents. [0198]
In the case where R 3 has a substituent, examples of said substituent include the above-described substituent T. [0199]
In the above-described formula (2), R 4 and R 5 each independently represent a single bond or a divalent connecting group.
As the "divalent connecting group" represented by the above-described R 4 and R 5 , preferred are an optionally substituted, straight chain, branched, or cyclic alkylene, arylene, or aralkylene group, or -O-, -S-, -C(=O)-, -N(R 19 )-, -SO-, -SO 2 -, -CO 2 -, or -N(R 20 )SO 2 -, or a divalent group formed by combining two or more of these groups (wherein R 19 and R 20 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms). The above-described divalent connecting group is preferably an organic connecting group. [0200]
As the R 4 , preferred are a straight chain or branched, alkylene or aralkylene group, or -O-, -C(=O)-, -N(R 19 )-, -SO 2 -, -CO 2 -, or -N(R 20 )SO 2 -, or a divalent group formed by combining two or more of these groups. Especially preferred are a straight chain or branched, alkylene or aralkylene group, or -O-, -C(=O)-, -N(R 19 )-, or -CO 2 -, or a divalent group formed by combining two or more of these groups. [0201]
As the R 5 , preferred are a single bond, a straight chain or branched, alkylene or aralkylene group, or -O-, -C(=O)-, -N(R 19 )-, -SO 2 -, -CO 2 -, or -N(R 20 )SO 2 -, or a divalent group formed by combining two or more of these groups. Especially preferred are a straight chain or branched, alkylene or aralkylene group, or -O-, -C(=O)-, -N(R 19 )-, or -CO 2 -, or a divalent group formed by combining two or more of these groups. [0202]
In the case where R 4 or R 5 have a substituent, examples of said substituent include the above- described substituent T. [0203]
P 2 in formula (2) represents a polymer compound residue (a polymer skeleton) and can be properly selected from ordinary polymers. Preferred embodiments of the polymers are the same as P 1 in above-described formula (1) and a preferred embodiment thereof is also the same as P 1 . [0204] Among polymer compounds represented by the above-described formula (2), especially preferred are polymer compounds in which R 3 is the above-described specific group of (r-1), (r-2), (r-10), (r-1 1), (r- 16), or (r-17); R 4 is a single bond, a straight chain or branched, alkylene or aralkylene group, or -O-, -C(=O)-, -N(R 19 )-, or -CO 2 -, or a divalent organic group formed by combining two or more of these groups; R 5 is a single bond, an ethylene group, a propylene group, or a connecting group represented by formula (s- a) or (s-b) set forth below; P 2 is a homopolymer or copolymer derived from a vinyl monomer, an ester compound polymer, an ether compound polymer, a urethane compound polymer, or a modified compound of these polymers; y is 1 to 2; and x is 3 to 6. In the following groups, R 21 represents a hydrogen atom or a
methyl group; 1 represents 1 or 2. [0205] [Chemical formula 29]
The weight-average molecular weight of the above-described polymer compound is at least 1,000, preferably from 3,000 to 100,000, more preferably from 5,000 to 80,000, and especially preferably from 7,000 to 60,000. If the weight-average molecular weight is within the above-described range, a plurality of functional groups introduced to the terminal(s) of the polymer fully exhibit their effects, and thus the polymer compound will exhibit excellent performances in terms of adsorption properties onto a solid surface, micelle-forming property, and surface activating property. Thereby, good dispersibility and dispersion stability can be attained. [0207]
Specific examples of the compound represented by formula (1) are shown below. However, the present invention is not limited to these specific examples.
[0208] [Chemical formula 30]
[0209] [Chemical formula 31]
[0210] [Chemical formula 32]
[0211] [Chemical formula 33]
[0212] [Chemical formula 34]
[0213] [Chemical formula 35]
[0214] [Chemical formula 36]
[0215] [Chemical formula 37]
[0216] [Chemical formula 38]
[0217] [Chemical formula 39]
[0218] [Chemical formula 40]
[0219] [Chemical formula 41]
[0220] [Chemical formula 42]
[0221] [Chemical formula 43]
[0222] [Chemical formula 44]
[0223] [Chemical formula 45]
[0224] [Chemical formula 46]
—
[0225] [Chemical formula 47]
(0-35)
[0226]
As the above-described polymer compound having a weight-average molecular weight of at least 1,000, it is possible to use any of the following polymer compounds having an acidic group (hereinafter, this compound is also referred to as an "acidic-group-containing polymer compound")- As the polymer compound, preferred is a polymer compound having a carboxyl group. More preferred are copolymer compounds containing (A) at least one repeating unit derived from a compound having a carboxyl group and (B) at least one repeating unit derived from a compound having a carboxylic acid ester group.
The repeating unit (A) derived from a compound having a carboxyl group is preferably a repeating unit represented by the following formula (I), and more preferably a repeating unit derived from acrylic acid or methacrylic acid; and the repeating unit (B) derived from a compound having a carboxylic acid ester group is preferably a repeating unit represented by the following formula (II), more preferably a repeating unit represented by the following formula (IV), and particularly preferably a repeating unit derived from benzyl acrylate, benzyl methacrylate, phenethyl acrylate, phenethyl methacrylate, 3- phenylpropyl acrylate, or 3-phenylpropyl methacrylate. [0227]
[Chemical formula 48]
(Ri represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.) [0228] [Chemical formula 49]
(R. 2 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R 3 represents a group represented by the following formula (III).) [0229] [Chemical formula 50]
(R 4 represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a hydroxy group, a hydroxyalkyl group having 1 to 5 carbon atoms, or an aryl group having 6 to 20 carbon atoms; R 5 and R 6
each represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; and i represents a number of 1 to 5.) [0230] [Chemical formula 51]
(R. 7 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Rg represents a group represented by the following formula (V).) [0231] [Chemical formula 52]
(R 9 represents an alkyl group having 2 to 5 carbon atoms or an aryl group having 6 to 20 carbon atoms.
R 10 and R 1 ] each represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, j represents a number of 1 to 5.)
As to a polymerization ratio between the repeating unit (A) derived from a compound having a carboxyl group and the repeating unit (B) derived from a compound having a carboxylic acid ester group, a ratio (%) of the number of the repeating units (A) to the total number of repeating units is preferably 3 to 40, and more preferably 5 to 35.
In the present specification, the term "molecular weight" of a polymer means a number average molecular weight, unless otherwise stated. Examples of a method of measuring the molecular weight of polymer include a chromatography method, a viscosity method, a light scattering method, and a sedimentation velocity method. In the present specification, a number-average molecular weight calculated in terms of polystyrene, measured by gel permeation chromatography (carrier: tetrahydrofuran) is used, unless otherwise specifically indicated.
[0232] The polymer compound may be either water-soluble or oil-soluble, or may be water-soluble and oil-soluble.
The polymer compound may be added in a state of being dissolved in an aqueous solvent or an organic solvent, or may be added in a solid state. In addition, such addition methods may be combined.
Examples of a method of adding the polymer compound in a state of being dissolved in a solvent include: a method involving adding, to an aggregated organic particles liquid, the polymer compound in a state of being dissolved in the same solvent as that of the aggregated organic particles liquid; and a method involving adding, to the aggregated organic particles liquid, the polymer compound in a state of being dissolved in a different solvent that is compatible with the solvent of the aggregated organic particles liquid.
When the polymer compound is added in a state of being dissolved in a solvent, the concentration of the polymer compound is not particularly limited, but the concentration is preferably 1 to 70 mass%, more preferably 2 to 65 mass%, and particularly preferably 3 to 60 mass%.
The polymer compound may be added at the time of or before or after the deposition and formation of the pigment fine particles, may be added at the time of or before or after concentration, may be added at the time of or before or after the dispersion of the aggregated organic particles after being subjected to concentration, or may be added after the completion of these steps. Alternatively, the polymer compound may be added in plural times by dividing the whole amount thereof into plural portions. In the present invention, the above-described polymer compound having a weight-average molecular weight of 1,000 or more may be incorporated in a composition as the aforementioned binder. For example, it is preferred that the polymer compound is added at the time of fining and dispersing the aggregated organic particles obtained after concentration of a pigment fine particles-depositing solution. [0233]
The polymer compound is added in an amount of preferably 0.1 to 1,000 parts by mass, more preferably 5 to 500 parts by mass, and particularly preferably 10 to 300 parts by mass, when the amount of pigment fine particles is set to 100 parts by mass.
Examples of the polymer compound include, other than the aforementioned compounds, polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl methyl ether, polyethylene oxide, polyethylene glycol, polypropylene glycol, polyacrylamide, vinyl alcohol/vinyl acetate copolymer, partial-formal products of polyvinyl alcohol, partial-butyral products of polyvinyl alcohol, vinylpyrrolidone/vinyl acetate copolymer, polyethylene oxide/propylene oxide block copolymer, polyamides, cellulose derivatives, and starch derivatives. Besides, natural polymer compounds can also be used, examples of which include alginic acid salts, gelatin, albumin, casein, gum arabic, tragacanth gum, and ligninsulfonic acid salts.
Examples of the polymer compound having an acidic group include polyvinyl sulfuric acid and concentrated naphthalenesulfonic acid. [0234]
Examples of the polymer compound having a carboxyl group include polyacrylic acid, polymethacrylic acid, and a cellulose derivative having a carboxyl group in any one of its side chains. Examples of the copolymer containing at least one repeating unit (A) derived from a compound having a carboxyl group and at least one repeating unit (B) derived from a compound having a carboxylic acid ester group, include a methacrylic acid copolymer, an acrylic acid copolymer, an itaconic acid copolymer, a crotonic acid copolymer, a maleic acid copolymer, and a partially-esterified maleic acid copolymer, as described in JP-A-59-44615, JP-B-54-34327, JP-B-58- 12577, JP-B-54-25957, JP-A-59-53836, and JP-A- 59-71048. In addition, particularly preferable examples of the copolymer include an acrylic acid/acrylate copolymer, a methacrylic acid/acrylate copolymer, an acrylic acid/methacrylate copolymer, a methacrylic acid/methacrylate copolymer, and a multiple-component copolymer containing acrylic acid or methacrylic acid, and an acrylate or methacrylate, and any other vinyl compound, as described in U.S. Patent No. 4,139,391.
Examples of the vinyl compound include styrene or a substituted styrene (such as vinyltoluene or vinyl ethyl benzene); vinylnaphthalene or a substituted vinylnaphthalene; acrylamide; methacrylamide; acrylonitrile; and methacrylonitrile. Of those, styrene is preferable. [0235]
The polymer compound having a weight average molecular weight of 1,000 or more may be used singly or in combination of two or more thereof, or may be used in combination with a compound having a molecular weight of less than 1 ,000. [0236] It is preferred that the dispersion of the pigment fine particles include an organic solvent in an amount of preferably 60 mass% or more, and more preferably 65 mass% or more. The organic solvent is not particularly limited, and can be appropriately selected from common solvents. Examples of a preferable solvent include ester compound solvents, alcohol compound solvents, aromatic compound solvents, aliphatic compound solvents, and ketone compound solvents. Of those, ester compound solvents and ketone compound solvents are particularly preferable. Those solvents may be used singly or in combination of two or more thereof. [0237]
Examples of the ester compound solvents include 2-(l-methoxy)propyl acetate, ethyl acetate, ethyl lactate, and the like. Examples of the alcohol compound solvents include n-butanol, isobutanol, and the like. Examples of the aromatic compound solvents include benzene, toluene, xylene, and the like.
Examples of the aliphatic compound solvents include n-hexane, cyclohexane, and the like. Examples of the ketone compound solvents include methylethylketone, acetone, cyclohexanone, and the like. [0238]
The aforementioned pigment fine particles can be used, for example, in a state dispersed in a vehicle. If paint is taken as an example, the vehicle means a portion of a medium in which a pigment is dispersed when the paint is in a liquid state. The vehicle is a liquid state and contains a portion (binder) that is to be bonded to the pigment to solidify a coating film and a component (organic solvent) for dissolving and diluting the portion. In the present invention, a binder to be used at the time of the formation of the nanoparticles and a binder to be used in redispersing may be identical to or different from each other, and they are sometimes separately referred to as a nanoparticle formation binder and a redispersion binder, respectively.
The concentration of pigment fine particles in a dispersion composition of the pigment fine particles after re-dispersion can be properly determined in accordance with a purpose of their use. However, the concentration of the pigment fine particles is preferably in the range of from 2 to 30 mass%, more preferably in the range of from 4 to 20 mass%, and especially preferably in the range of from 5 to 15 mass%, based on the total amount of the dispersion composition. In the case where the pigment fine particles are dispersed with such vehicles as described above, amounts of the binder and the dissolution and dilution component can be properly determined depending on, for example, the kind of the organic pigment. However, the amount of the binder is preferably in the range of from 1 to 30 mass%, more preferably in the range of from 3 to 20 mass%, and especially preferably in the range of from 5 to 15 mass%, based on the total amount of the dispersion composition. The amount of the dissolution and dilution component is preferably in the range of from 5 to 80 mass%, and more preferably in the range of from 10 to 70 mass%, based on the total amount of the dispersion composition. [0239] In the aforementioned, concentrated, extracted nanoparticle liquid, it is preferred to cause aggregation of pigment fine particles by concentration, in order to allow quick filtration through a filter, as previously described. It is preferred to cause aggregation by concentrating by centrifugal separation or
drying.
Examples of a method that can be employed for fining and dispersing such aggregated nanoparticles, include a dispersing method with using a supersonic wave and a method involving applying physical energy. Apparatus for ultrasonic wave irradiation is preferably an apparatus that is capable of applying an ultrasonic wave at 10 kHz or more, and examples thereof include an ultrasonic wave homogenizer, an ultrasonic wave cleaning machine, and the like. The liquid temperature during ultrasonic wave irradiation is preferably kept at 1 to 100 °C, more preferably 5 to 60 0 C, since increase in the liquid temperature leads to thermal aggregation of nanoparticles (see "Current Pigment Dispersion Technology", Technical Information Institute Co., Ltd., 1995, p.166). The temperature can be controlled, for example, by adjusting the temperature of dispersion, by adjusting the temperature of a temperature-controlling layer for controlling of dispersion temperature, or the like.
A dispersion machine to be used at the time of dispersing the concentrated pigment fine particles by the application of physical energy is not particularly limited, and examples of the dispersion machine include a kneader, a roll mill, an attritor, a super mill, a dissolver, a homomixer, and a sand mill. Further, a high pressure dispersion method and a dispersion method of using fine particle beads are also exemplified as a preferable method.
[0240]
By the above-described production method, it is possible, for example, to concentrate and re- disperse the pigment fine particles to be contained in each of the pigment fine particle dispersion composition and colored photosensitive resin composition, irrespective of their minute particle diameters as small as a nanometer size (for example, 10 to 100 run). Accordingly, use of either of the compositions in a color filter can obtain a color filter which exhibits a high optical density, is excellent in uniformity of the filter surface, gives a high contrast, and has reduced image noise. Further, the pigment fine particles to be contained in the pigment fine particle dispersion composition or colored photosensitive composition can be dispersed in fine-particle states of being highly and uniformly reduced in size. Accordingly, a film formed of each of the compositions exerts a high coloring density even with a small thickness, thereby enabling a reduction in thickness of, for example, a color filter. In addition, each of the pigment fine particle dispersion composition and colored photosensitive resin composition can be advantageously used as an image forming material for producing, for example, a color proof or a color filter, when a pigment showing a clear color tone and high coloring power is incorporated into each of the compositions.
Further, each of the pigment fine particle dispersion composition and colored photosensitive resin composition can use a binder which is soluble in an alkaline aqueous solution in order to get along with an alkaline developer for use in exposure and development at the time of the formation of a colored image, thus each of the compositions can meet the need for environment protection.
In addition, an organic solvent having a suitable drying property can be used as a solvent (a dispersion medium for a pigment) for use in each of the pigment fine particle dispersion composition and colored photosensitive resin composition, and the resultant compositions can satisfy the need in drying after coating the compositions.
The color filter of the present invention has a high contrast and an excellent hue, and it is also
suitable for a continuous mass production on an industrial scale. When applied to a liquid crystal display device or a CCD device, the color filter of the present invention can exhibit excellent display characteristics.
The present invention will be described in more detail based on the following examples, but the present invention is not limited thereto.
[0241]
EXAMPLES (Example 1-1)
To 1000 ml of dimethylsulfoxide (manufactured by Wako Pure Chemical Industries, Ltd.), were added 10 ml of 28% methanol solution of sodium methoxide (manufactured by Wako Pure Chemical Industries, Ltd.), 10,000 mg of C.I. Pigment Red 254 (Irgaphor Red BT-CF, manufactured by Ciba Specialty Chemicals), 10,000 mg of polyvinyl pyrrolidone K25 (manufactured by Wako Pure Chemical Industries, Ltd.), to prepare a pigment solution. Separately from the pigment solution, 9,000 ml of ion- exchanged water containing 100 ml of 1 N hydrochloric acid (manufactured by Wako Pure Chemical Industries, Ltd.) was prepared as a poor solvent.
The whole quantity of the pigment solution was injected at a current velocity of 100 ml/min, using a non-pulsating current pump, to the above-described poor solvent controlled to a temperature of 18 0 C and agitated with a four-blade propeller at 500 rpm, thereby to prepare a pigment particle dispersion having a pigment concentration of 0.1 mass%. The thus-prepared pigment dispersion was subjected to filtration under reduced pressure using a PTFE membrane filter and then washed, followed by concentration up to a pigment concentration of 20 mass%. By a measurement with electron microscope, it was found that the average particle diameter of the pigment particles was 22 nm.
Using the thus-prepared pigment condensate, R pigment dispersion 1-1 was prepared with the composition described in Table 1. [0242]
[0243]
In Table 1 , the high molecular dispersing agent 1 was one produced by random copolymerization of benzyl methacrylate and methacrylic acid in a molar ratio of 60/40. The number-average molecular weight (Mn) thereof was 32,000 in measurement according to a gel permeation chromatography. Further, the compound Jl set forth below was used as the dispersing agent A. [0244] [Chemical formula 53]
[0245]
Using the above-described R-pigment dispersion 1-1, a colored photosensitive resin composition Rl-I was prepared according to the composition described in Table 2. [0246]
[0247] <Binder>
• Polymer (random copolymer of benzyl methacrylate/methacrylic acid/methyl methacrylate (38/25/37 by mole ratio); Mn: 40,000): 25 parts by mass
• Propylene glycol monomethyl ether acetate: 75 parts by mass [0248]
<Dipentaerythritol hexacrylate solution (DPHA solution) >
• Dipentaerythritol hexacrylate (containing polymerization inhibitor MEHQ at 500 ppm; manufactured by Nippon Kayaku; Trade name: KAYARAD DPHA): 70 parts by mass
• Propylene glycol monomethyl ether acetate: 30 parts by mass [0249]
<Polymerization initiator A>
• 2,4-bis(trichloromethyl)-6-[4'-(N,N-bisethoxycarbonylmethyl) amino-3'-
bromopheny 1] -s-triazine [0250]
<Surfactant>
• Structure 1 set forth below: 24 parts by mass • Methyl ethyl ketone: 76 parts by mass
[0251] [Chemical formula 54]
[0252] A color filter 1-1 provided with a black matrix, R pixel, G pixel, and B pixel was prepared as described below.
[0253]
[Preparation of color filter (preparation by means of coating with a slit nozzle)]
<Formation of black (K) image> A non-alkali glass substrate was washed using a UV washing machine, and thereafter washed with a brush using a detergent, and then further subjected to ultrasonic cleaning with ultra pure water. The substrate was subjected to a thermal processing at 120 0 C for 3 minutes, thereby to stabilize the surface state of the substrate.
The substrate was cooled and temperature controlled to 23 0 C. On the substrate, a colored photosensitive resin composition Kl having the composition described in the following Table 3 was coated with a slit nozzle-equipped coater for a glass substrate (manufactured by F.A.S. Japan Corp., trade name:
MH- 1600). Subsequently, a part of the solvent was dried using VCD (vacuum drying apparatus, manufactured by Tokyo Ohka Kogyo) for 30 seconds, thereby to eliminate fluidity of the coating layer.
Thereafter, an unnecessary coating liquid at a surround of the substrate was removed with EBR (edge bead remover). After pre-baking at 120 0 C for 3 minutes, 2.4 μm thick photosensitive resin layer K was obtained.
[0254]
[0255]
In a proximity type exposure apparatus equipped with an ultra-high pressure mercury lamp (manufactured by Hitachi Engineering), the substrate and a mask (silica exposure mask having an image pattern) were stood vertically, and in this state, the distance between the exposure mask surface and the photosensitive resin layer was set to 200 μm; and then, a pattern exposure was conducted in an exposure amount of 300 mJ/cm 2 .
Subsequently, the surface of the photosensitive resin layer Kl was uniformly wetted by splaying pure water with a shower nozzle. Thereafter, the photosensitive resin layer was shower developed under conditions of flat nozzle pressure of 0.04 MPa with a KOH-series developer (developer containing KOH and a nonionic surfactant; trade name: CDK-I; manufactured by Fuji Film Electronics Materials) at 23 0 C for 80 seconds. Thereby, a patterned image was obtained. Subsequently, ultra pure water was sprayed at a pressure of 9.8 MPa using an ultra-high-pressure cleaning nozzle, to eliminate a residue. Thus, a black (K) image K was obtained. Subsequently, the image was subjected to a thermal processing at 220 0 C for 30 minutes. [0256]
The above-described colored photosensitive resin composition K was prepared as follows: First, carbon black and propylene glycol mono methyl ether acetate were weighed, and then they were mixed at a temperature of 24 0 C (±2 0 C) and stirred at 150 rpm for 10 minutes. Thereafter, methyl ethyl ketone, the binder, hydroquinone mono methyl ether, the DPHA solution, the polymerization initiator A, and the surfactant were weighed, and they were added in this order at a temperature of 25 °C (±2 0 C), and then the resultant mixture was stirred at 150 rpm at 40 0 C (±2 0 C) for 30 minutes. [0257] <Formation of red (R) pixel>
On the substrate having formed thereon the above-described image K, a thermally treated pixel R was formed using the above-described colored photosensitive resin composition Rl-I in the same steps as formation of the black (K) image. The film thickness of the thus-obtained photosensitive resin layer R and the coating amount of the pigment were shown below. The colored photosensitive resin composition Rl-I was prepared in the same manner as the above-described colored photosensitive resin composition K. Film thickness of photosensitive resin (μm) 1.60 Coating amount of pigment (g/m 2 ) 1.00
Coating amount of C. I. P. R. 254 (g/m 2 ) 0.80
[0258] <Formation of green (G) pixel>
On the substrate having formed thereon the above-described image K and pixel R, a thermally treated pixel G was formed using the colored photosensitive resin composition G having the composition shown below Table 4 in the same steps as formation of the black (K) image. The film thickness of the thus-obtained photosensitive resin layer G and the coating amount of the pigment were shown below. The
colored photosensitive resin composition G was prepared in the same manner as the above-described colored photosensitive resin composition K.
Film thickness of photosensitive resin (μm) 1.60
Coating amount of pigment (g/m 2 ) 1.92
Coating amount of C. I. P. G. 36 (g/m 2 ) 1.34
Coating amount of C. I. P. Y. 150 (g/m 2 ) 0.58
[0259]
[0260]
<G-pigment dispersion>
• C.I.P.G.36 18 parts by mass
• Polymer (random copolymer of benzyl methacrylate/methacrylic acid (72/28 by mole ratio); Molecular weight: 38,000) 12 parts by mass
• Cyclohexanone 35 parts by mass
• Propylene glycol monomethyl ether acetate 35 parts by mass <Y-pigment dispersion>
• CF Yellow EX3393 (trade name) manufactured by Mikuni Color Ltd [0261]
<Formation of blue (B) pixel>
On the substrate having formed thereon the above-described image K, pixel R, and pixel G, a thermally treated pixel B was formed using the colored photosensitive resin composition Bl having the composition shown below Table 5 in the same steps as formation of the black (K) image. In this manner, the desired color filter A was obtained. The film thickness of the thus-obtained photosensitive resin layer Bl and the coating amount of the pigment were shown below. The colored photosensitive resin composition B 1 was prepared in the same manner as the above-described colored photosensitive resin composition K.
Film thickness of photosensitive resin (μm) 1.60
Coating amount of pigment (g/m 2 ) 0.75
Coating amount of C. 1. P. B. 15:6 (g/m 2 ) 0.67
Coating amount of C. I. P. V. 23 (g/m 2 ) 0.075
[0262]
<B-pigment dispersion>
• CF Blue EX3357 (trade name) manufactured by Mikuni Color Ltd. <V-pigment dispersion>
• CF Blue EX3383 (trade name) manufactured by Mikuni Color Ltd. [0264]
(Example 1-2)
A R-pigment dispersion 1-2, a colored photosensitive resin composition Rl-2, and a color filter
1-2 using the colored photosensitive resin composition Rl-2 were prepared in the same manner as in
Example 1-1, except that the amount of polyvinyl pyrrolidone used at the time of preparing the R-pigment dispersion 1-1 was changed to 20,000 mg. By a measurement with electron microscope, it was found that the average particle diameter of the pigment particles was 23 nm.
[0265]
(Example 1-3)
A R-pigment dispersion 1-3, a colored photosensitive resin composition Rl-3, and a color filter 1-3 using the colored photosensitive resin composition Rl-3 were prepared in the same manner as in
Example 1-1, except that the amount of polyvinyl pyrrolidone used at the time of preparing the R-pigment dispersion 1-1 was changed to 50,000 mg. By a measurement with electron microscope, it was found that the average particle diameter of the pigment particles was 21 nm.
[0266] (Example 1-4)
A R-pigment dispersion 1-4, a colored photosensitive resin composition Rl -4, and a color filter
1-4 using the colored photosensitive resin composition R 1-4 were prepared in the same manner as in
Example 1-1, except that the amount of polyvinyl pyrrolidone used at the time of preparing the R-pigment dispersion 1-1 was changed to 100,000 mg. By a measurement with electron microscope, it was found that the average particle diameter of the pigment particles was 20 nm.
[0267]
(Example 2)
A R-pigment dispersion 2, a colored photosensitive resin composition R2, and a color filter 2 using the colored photosensitive resin composition R2 were prepared in the same manner as in Example 1-1 , except that 50,000 mg of polyvinyl pyrrolidone K.90 (manufactured by Wako Pure Chemical Industries, Ltd.) was added in place of polyvinyl pyrrolidone K25 at the time of preparing the R-pigment dispersion 1- 1. By a measurement with electron microscope, it was found that the average particle diameter of the pigment particles was 20 nm. (Example 3)
A pigment dispersion and a pigment condensate were prepared in the same manner as in Example 1-4, except that the temperature of the poor solvent was changed to 45 0 C. By a measurement with electron microscope, it was found that the average particle diameter of the pigment particles was 53 nm.
With using the thus-obtained pigment condensate, a R-pigment dispersion 3, a colored photosensitive resin composition R3, and a color filter 3 using the colored photosensitive resin composition R3 were prepared in the same manner as in Example 1 - 1. [0268] (Comparative example 1 )
A R-pigment dispersion A, a colored photosensitive resin composition RA, and a color filter A using the colored photosensitive resin composition RA were prepared in the same manner as in Example 1-
1, except that a pigment stock liquid was prepared without adding polyvinyl pyrrolidone at the time of preparing the R-pigment dispersion 1-1. By a measurement with electron microscope, it was found that the average particle diameter of the pigment particles was 21 nm. [0269] (Comparative example 2)
First, 20,000 mg of methacrylic acid/benzyl methacrylate copolymer (molar ratio 30/70, Mw 30,000, 40 mass% propylene glycol mono methyl ether acetate solution), 80,000 mg of sodium chloride, and 80,000 mg of C. I. Pigment Red 254 were mixed. Then, the resultant mixture was loaded in a dual arm type kneader (manufactured by Moriyama Company Ltd.) and kneaded at 80 0 C for 10 hours. After kneading, the mixture was taken to 500 mass parts of 1 mass% hydrochloric acid aqueous solution, and then stirred for 1 hour, followed by filtration, washing with a hot water, drying, and grinding. Thereafter, 2.4 g of propylene glycol mono methyl ether acetate per 1 g of the ground product were added and mixed. The resultant pigment composition was dispersed with using zirconia beads of 0.5 mm in diameter, at a peripheral speed of 10 m/s, for 1 hour, using a motor mill M-50 (manufactured by Eigar Japan). The thus- obtained pigment dispersion was designated as R-pigment dispersion B. By a measurement with electron microscope, it was found that the average particle diameter of the pigment particles was 48 nm.
Using the R-pigment dispersion B, were prepared a colored photosensitive resin composition RB and a color filter B using the colored photosensitive resin composition RB in the same manner as in Example 1-1. [0270]
The amount of polyvinyl pyrrolidone in each of the thus-prepared pigment dispersions 1-1 to 1-4,
2, 3, A, and B was measured as described below. 1. Pigment dispersions were each subjected to evaporation to dryness at 100 °C and at atmospheric pressure. Each of the thus-obtained solids was ground. 2. Each of the ground products was made into tablets according to a KBr method to prepare samples. The
amount of polyvinyl pyrrolidone in each of the samples was determined using a Fourier transform infrared spectrophotometer FTIR-8400S (trade name) manufactured by Shimadzu Corporation.
Further, the moisture content in each of the pigment dispersions 1-1 to 1-4, 2, 3, A, and B was measured using a Karl Fisher moisture meter MKA-3 manufactured by Kyoto Electronics Manufacturing Co., Ltd. [0271] Table 6
In order to evaluate performances of the thus-prepared pigment dispersions 1-1 to 1-4, 2, 3, A, and B, contrast of the coated product was measured according to the following method. As a backlight unit, a three- wave length cold-cathode-tube light source (FWL18EX-N, trade name, manufactured by Toshiba Lighting & Technology Corporation) provided with a diffuser plate was used. Each of the color filters was placed between two sheets of polarizing plates (HLC2-2518, trade name, manufactured by Sanritz Corporation), and then amounts of transmitted light at the time when polarization axes of two polarizing plates were parallel and the time when the polarization axes were perpendicular were measured. The ratio of these transmitted light amounts was defined as a contrast (see Color Filter for 512 color display 10.4"-size TFT-LCD, co-authored by Ueki, Koseki, Fukunaga, and Yamanaka, The seventh Color Optics Conference (1990), etc.). Chromaticity was measured using a color luminance meter (BM-5 (trade name), manufactured by Topcon Techno House Corporation). The above-described two sheets of polarizing plates, color filter, and color luminance meter were placed at the following positions: A polarizing plate was disposed at the distance of 13 mm from the backlight. A cylinder of 1 1 mm in diameter and 20 mm in length was disposed at the distance of 40 mm to 60 mm from the backlight. The light transmitted through the cylinder was irradiated to a color filter disposed at the distance of 65 mm from the backlight. The transmitted light was passed through another polarizing plate disposed at the distance of 100 mm from the backlight and measured with a color luminance meter disposed at the distance of 400 mm from the backlight. The measuring angle in the color luminance meter was set to 2°. The light amount of the backlight was set so that its brightness (luminance) would be 1280 cd/m", when the two sheets of polarizing plates were arranged in a position of parallel nicol and no color filter was disposed.
[0273]
Next, the amount of polyvinyl pyrrolidone contained in the colored layer of each of the thus- prepared color filters 1-1 to 1-4, 2, 3, A, and B was measured as described below.
1. A part of the colored layer of each color filter was scratched off with a spatula under a stereoscopic micrometer, to prepare samples for analysis.
2. A suitable amount of each sample was collected and analyzed according to a pyrolysis gas chromatography mass spectrometry. For pyrolysis, Curie Point Pyrolyzer JHP-5 Model pyrolysis apparatus (trade name) manufactured by JAI Corporation was used. The gas chromatography mass spectrometry was performed using 5973-Model apparatus (trade name) manufactured by Agilent Technologies Corporation.
3. Analysis of polyvinyl pyrrolidone was performed according to the SIM method. Quantitative values were calculated according to an absolute calibration curve method or a standard addition method. [0274]
The contrast in the case where the pigment dispersions were coated and the content of the polymer (polyvinyl pyrrolidone) in color filter were shown in Table 7. [0275]
(Note 1) The contrast of the pigment dispersion measured according to the above-described measurement method
(Note 2) The content of the water-soluble polymer (polyvinyl pyrrolidone) in the color filter, based on the solid content
[0276]
From the results, it is understood that the contrast of each of the color filters 1-1 to 1-4, 2, and 3, in which 0.1 mass% or more of polyvinyl pyrrolidone (water-soluble polymer) was contained in the colored layer, was higher than those of the color filters A and B. It is expected that liquid crystal display devices and CCD devices equipped with the color filters 1-1 to 1-4, 2, and 3 would show improved performances.
The color filter 3 showed a relatively lower contrast though it contained the water-soluble polymer. It is assumed that this result can be attributed to the fact that the pigment particles contained in the color filter 3 had a diameter as large as about 50 nm. In this connection, the color filter 3 exhibited superior contrast to the color filter B, though they included pigment particles almost identical in their
particle diameter, showing an effect attributable to inclusion of the water-soluble polymer.
[0277]
(Example 4 and Comparative example 3)
Next, liquid crystal display devices mounted with the above-described color filters were respectively produced as described below, and image quality evaluation thereof was conducted. . [0278]
[Production of liquid crystal display devices] (Formation of ITO electrode)
A glass substrate having a color filter formed thereon was loaded in a sputter apparatus, and 1300 A thick ITO (indium tin oxide) was vacuum deposited at 100 0 C on the whole surface of the said glass substrate. Thereafter, annealing at 240 0 C for 90 minutes was performed, to crystallize the ITO. Thus, ITO transparent electrode was formed. [0279]
(Formation of spacer) A spacer was formed on the thus-prepared ITO transparent electrode in the same manner as the spacer-forming method described in Example 1 of JP-A-2004-240335. [0280] (Formation of protrusion for controlling orientation of liquid crystal)
Using a coating liquid for a positive type photosensitive resin layer described below, a protrusion for controlling orientation of liquid crystal was formed on the ITO transparent electrode formed with the above-described spacer.
Herein, exposure, development, and bake steps were carried out according to the following method.
A proximity-type exposure equipment (manufactured by Hitachi High-Tech Electronics Engineering Co., Ltd.) was set so that a certain photo mask would be located at the distance of 100 μm from the surface of the photosensitive resin layer. A proximity exposure was carried out through the said photo mask in an exposure amount of 150 mJ/cm 2 using an ultra-high pressure mercury lamp. [0281]
Subsequently, development was conducted by spraying a 2.38% tetramethyl ammonium hydroxide solution on to the substrate at 33 °C for 30 seconds using a shower-type developing apparatus. In this manner, unnecessary portions (exposed portions) of the photosensitive resin layer were removed by development. Thereby, on the substrate at the same side as the color filter, was formed the objective protrusion for controlling orientation of liquid crystal that was made by patterning the photosensitive resin layer into a desired shape. After that, the substrate for a liquid crystal display device having formed thereon the protrusion for controlling orientation of the liquid crystal was baked under the conditions of 230 °C for 30 minutes. Thereby, a cured protrusion for controlling orientation of the liquid crystal was formed on the substrate for a liquid crystal display device. [0282] <Formulation of positive-type photosensitive-resin-layer coating liquid>
• Positive-type resist solution (FH-2413F (trade name), manufactured by Fuji Film
Electronics Materials) 53.3 mass parts
• Methyl ethyl ketone 46.7 mass parts
• Megafac F-780F (trade name, manufactured by Dainippon Ink & Chemicals
Incorporation) 0.04 mass part
[0283] (Production of liquid crystal display devices)
An alignment film composed of polyimide was further provided on the thus-obtained substrate for a liquid crystal display device. Thereafter, a sealing agent made of an epoxy resin was printed at the positions corresponding to the outer frame of the black matrix that was disposed so as to surround the periphery of the pixels of the color filter. In addition, after dropping thereon a liquid crystal for MVA- mode, the above-described substrate and a counter substrate were stuck together. The stuck substrates were subjected to a thermal processing to cure the sealing agent. On each surface of the thus-obtained liquid crystal cell, a polarizing plate HLC2-2518 manufactured by Sanritz Corporation was stuck together. Subsequently, a backlight with a three-wavelength cold-cathode tube light source (FWLl 8EX-N (trade name), manufactured by Toshiba Lighting & Technology Corporation) was formed, and the backlight was set at the back side of the liquid crystal cell provided with the polarizing plates. Thus, the liquid crystal display device was produced. [0284]
With respect to the thus-produced liquid crystal display devices, the liquid crystal display device provided with the color filter 1-1 was designated as liquid crystal display device 1-1. In the same manner as the above, liquid crystal display devices 1-2 to 1-4, 2, 3, A, and B were produced, respectively. [0285]
Image quality of each liquid crystal display device was evaluated as follows.
1. Eight liquid crystal display devices described above were randomly arranged without putting a label thereto and shown to an examiner. The image quality (black depth and modulation) of devices were rated by the examiner in a scale of 8 points to 1 point, with a rating of 8 points being the best and a rating of 1 point being the worst.
2. The same evaluation test was conducted by 10 examiners. The thus-obtained scores were summed up, and the total scores were used to evaluate image quality of the prepared liquid crystal display devices.
A liquid crystal display device exhibiting the total score of 25 or more has sufficient properties for practical use.
The obtained results are shown in Table 8. [0286] Table 8 Results of image quality evaluation of the prepared liquid crystal display devices
[0287] From Table 8, it is understood that the liquid crystal display devices provided with the color filters having a colored layer in which polyvinyl pyrrolidone was contained in an amount of 0.1 mass% or more, realized excellent image quality. In addition, as in the case of the results shown in Table 7, it is understood that, in the samples which contained pigment particles, which were used as colorant for the color filter, almost identical in their particle diameter, image quality tended to be improved as polypyrrolidone content increased.
INDUSTRIAL APPLICABILITY [0288]
The color filter of the present invention has a high contrast and an excellent hue, and it is suitable for a continuous mass production on an industrial scale. When applied to a liquid crystal display device or a CCD device, the color filter of the present invention can exhibit excellent display characteristics. [0289]
Having described our invention as related to the present embodiments, it is our intention that the invention not be limited by any of the details of the description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claims.