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Title:
PHOTOCURABLE RESIN COMPOSITION AND OPTICAL MATERIAL
Document Type and Number:
WIPO Patent Application WO/2002/029448
Kind Code:
A2
Abstract:
The invention relates to a photocurable resin composition comprising the following components: a) a urethane (meth)acrylate produced by reacting compounds which at least comprise a polyether diol compound with a number average molecular weight of 200 to 500 containing a structure selected from the group consisting of a tetramethyleneoxy structure, a propyleneoxy structure, and a 1,2-butyleneoxy structure in the molecule, an organic polyisocyanate compound, and a hydroxyl group-containing (meth)acrylate, b) a monofunctional (meth)acrylate and c) a photoinitiator. The invention further relates to optical parts and products like projection TV's.

Inventors:
Tanabe, Takayoshi (2-18-33-M2-1 Umezone, Tsukuba, Ibaraki, 305-0045, JP)
Ukon, Masakatsu (2-15-2-401, Umezone Tsukuba, Ibaraki 305, JP)
Ueda, Jiro (2- Kawaguchi, Tsuchiura, Ibaraki, 13-28-213, JP)
Ukachi, Takashi (5-22-9, Kamiya, Ushiku, 300-1216, JP)
Application Number:
PCT/NL2001/000714
Publication Date:
April 11, 2002
Filing Date:
October 01, 2001
Export Citation:
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Assignee:
DSM N.V. (Het Overloon 1, TE Heerlen, NL-6411, NL)
JSR CORPORATION (JSR Building, 2-11-24 Tsukij, Chuo-ku Tokyo, 104-8410, JP)
JAPAN FINE COATINGS CO., LTD. (2-11-24, Tsukiji Chuo-ku, Tokyo, 104-8410, JP)
Tanabe, Takayoshi (2-18-33-M2-1 Umezone, Tsukuba, Ibaraki, 305-0045, JP)
Ukon, Masakatsu (2-15-2-401, Umezone Tsukuba, Ibaraki 305, JP)
Ueda, Jiro (2- Kawaguchi, Tsuchiura, Ibaraki, 13-28-213, JP)
Ukachi, Takashi (5-22-9, Kamiya, Ushiku, 300-1216, JP)
International Classes:
G03F7/027; C08F2/44; C08F2/50; C08F290/06; C08F299/06; C08G18/32; C08G18/48; C08G18/67; G02B1/04; (IPC1-7): G02B1/04
Foreign References:
US5903399A1999-05-11
US5712035A1998-01-27
Other References:
DATABASE WPI Section Ch, Week 199230 Derwent Publications Ltd., London, GB; Class A12, AN 1992-245723 XP002194495 & JP 04 164910 A (MITSUBISHI RAYON CO LTD) , 10 June 1992 (1992-06-10)
CHEMICAL ABSTRACTS, vol. 120, no. 16, 18 April 1994 (1994-04-18) Columbus, Ohio, US; abstract no. 193318, XP000372074 & JP 05 255463 A (NIPPON KAYAKU KK) 13 March 1992 (1992-03-13)
Attorney, Agent or Firm:
Renkema, Jacob (DSM Patents & Trademarks, P.O. Box 9, MA Geleen, NL-6160, NL)
Download PDF:
Claims:
CLAIMS
1. A photocurable resin composition comprising the following components (A), (B), and (C): (A) a urethane (meth) acrylate produced by reacting compounds which at least comprise a polyether diol compound with a number average molecular weight of 200 to 500 containing a structure selected from the group consisting of a tetramethyleneoxy structure, a propyleneoxy structure, and a 1,2butyleneoxy structure in the molecule, an organic polyisocyanate compound, and a hydroxyl groupcontaining (meth) acrylate (B) a monofunctional (meth) acrylate (C) a photoinitiator.
2. The photocurable resin composition according to claim 1, wherein the (A) urethane (meth) acrylate is produced by reacting compounds comprising a diol compound represented by the formula (1) (1) wherein each R'individually represents a hydrogen atom or a methyl group, each R2 individually represents an oxygen atom or sulfur atom, R3 is a groupCH2,C (CH3) 2,S,SO, orS02, Xl to X4 individually represent a hydrogen atom, methyl group, or bromine atom, and m and n individually represent a number from 1 to 9.
3. A photocurable resin composition comprising the following components (A), (B), and (C): (A) a urethane (meth) acrylate produced by reacting at least four compounds which at least comprise a polyether diol compound with a number average molecular weight of 200 to 500 containing a structure selected from the group consisting of a tetramethyleneoxy structure, a propyleneoxy structure, and a 1,2butyleneoxy structure in the molecule, a diol compound represented by the following formula (1), an organic polyisocyanate compound, and a hydroxyl groupcontaining (meth) acrylate, to wherein each R'individually represents a hydrogen atom or a methyl group, each R2 individually represents an oxygen atom or sulfur atom, R3 is a groupCH2,C (CH3) 2,S,SO, orSO2, X to X4 individually represent a hydrogen atom, methyl group, or bromine atom, and m and n individually represent a number from 1 to 9; (B) a monofunctional (meth) acrylate represented by the following formula (2); wherein R4 represents a hydrogen atom or a methyl group, R5 represents (CH2CH20) p, (CH (CH3) CHO) q, or CH2CH (OH) CH20 (wherein p and q represent integers from 0 to 10), and Y'to Y3 individually represent a hydrogen atom, a bromine atom, an alkyl group having 110 carbon atoms, phenyl group, or C (CH3) 2C6H5; and (C) a photoinitiator.
4. The photosensitive resin composition according to anyone of claims 13, which further comprises 0.001 to 10 parts by weight of polyoxyalkylene alkyl ether phosphate of the following formula (3) as component (D) for 100 parts by weight of the components (A), (B), and (C), wherein R6 is an alkyl group or an alkylsubstituted phenyl group with the alkyl group having 120 carbon atoms, r is an integer from 1 to 15, and A is OH or R80 (CH2CH (R7) O) s, wherein R is an alkyl group or an alkyl substituted phenyl group with the alkyl group having 120 carbon atoms, s is a number from 1 to 15, and R7 represents a hydrogen atom or methyl group.
5. The photocurable resin composition according to anyone of claims 14, wherein the component (A) is a mixture of (i) a urethane (meth) acrylate produced by reacting a polyether diol compound with a number average molecular weight of 200 to 500 containing a tetramethyleneoxy structure in the molecule, a diol compound represented by the formula (1), an organic polyisocyanate compound, and a hydroxyl groupcontaining (meth) acrylate, and (ii) a urethane (meth) acrylate produced by reacting a polyether diol compound with a number average molecular weight of 200 to 500 containing a 1,2butyleneoxy structure in the molecule, a diol compound represented by the formula (1), an organic polyisocyanate compound, and a hydroxyl groupcontaining (meth) acrylate.
6. The photocurable resin composition according to any one of claims 1 to 5, wherein the cured product made from the photocurable resin composition has a refractive index of 1.53 or more at 25°C.
7. The photocurable resin composition according to any one of claims 1 to 6, which is used for forming an optical part.
8. An optical part comprising a cured product produced by curing the resin composition according to any one of claims 17.
9. A projection TV comprising an optical part obtainable by curing the resin composition according to anyone of claims 17.
Description:
PHOTOCURABLE RESIN COMPOSITION AND OPTICAL MATERIAL Detailed Description of the Invention Field of the Invention The present invention relates to a photocurable resin composition. More particularly, the present invention relates to a photocurable resin composition useful for forming optical parts, for example, a prism lens sheet used for a backlight of a liquid crystal display and a Fresnel lens sheet or a lenticular lens sheet used for a screen of a projection TV or a backlight using such sheets.

Prior Art Lenses such as a Fresnel lens and a lenticular lens have been manufactured by a press method or a cast method which require a long period of time for manufacturing. Therefore, productivity of there methods was poor. In order to solve this problem, a method of manufacturing a lens using a UV-curable resin has been attempted in recent years. Such a method comprises pouring a UV-curable resin composition between a mold having a lens shape and a transparent resin substrate and curing the composition by irradiating ultraviolet rays from the side of the substrate. This method ensures manufacture of a lens in a short period of time. Accompanied by the development of thinner and larger projection TVs or video projectors, resins for forming a lens provided with various lens properties such as a higher refractive index and mechanical properties have been proposed and studied. For example, Japanese Patent Application Laid- open No. 2554363/1993 discloses a UV-curable resin composition for a translucent screen which comprises (A) a urethane (meth) acrylate produced by reacting (a) a diol compound produced by reacting bisphenol A with ethylene oxide and the like, (b) a diol compound with a molecular weight of 200 or less, (c) an organic polyisocyanate, and (d) a hydroxyl group-containing (meth) acrylate, (B) a compound containing an ethylenically unsaturated group other than the component (A), and (C) a photoinitiator.

Problems to be Solved by the Invention Recent wide acceptance of projection TVs and video projectors has diversified the

types of Fresnel lens and lenticular lens used therein, resulting in diversification of lens materials and combinations of Fresnel lens and lenticular lens. A high lens shape precision is required to realize fine expression of display images on a screen. However, conventional UV curable resin compositions neither exhibit satisfactory adhesion to diversified substrates, nor produce a cured product with a sufficiently high shape precision required for lenses, such as abrasion resistance, breaking resistance, and shape restorability, in the combinations of Fresnel lens and lenticular lens.

Means for Solving the Problems The present inventors have conducted extensive studies to solve the problems in conventional resin compositions. As a result, the inventors have found that optical parts, in particular, a translucent screen such as a Fresnel lens and a lenticular lens having a high refractive index and exhibiting excellent adhesion to diversified substrates, as well as superior abrasion resistance and restorability in the combinations of Fresnel lens and lenticular lens, can be manufactured by using a cured product of a photocurable resin composition comprising (A) a urethane (meth) acrylate produced by reacting compounds which at least comprise a polyether diol compound with a number average molecular weight of 200 to 500 containing a structure selected from the group consisting of a tetramethyleneoxy structure, a propyleneoxy structure, and a 1,2-butyleneoxy structure in the molecule, an organic polyisocyanate compound, and a hydroxyl group-containing (meth) acrylate, (B) a monofunctional (meth) acrylate, and (C) a photoinitiator.

The urethane (meth) acrylate is preferably produced by reacting the above mentioned components with also a diol compound represented by the formula (1).

These finding have led to the completion of the present invention.

Preferably, the present invention provides a photocurable resin composition comprising the following components (A), (B), and (C): (A) a urethane (meth) acrylate produced by reacting at least four compounds which at least comprise a polyether diol compound with a number average molecular weight of 200 to 500 containing a structure selected from the group consisting of a tetramethyleneoxy structure, a propyleneoxy structure, and a 1,2-butyleneoxy structure in the molecule, a diol compound represented by the following formula (1), an organic polyisocyanate compound, and a hydroxyl group-containing (meth) acrylate ;

wherein each R'individually represents a hydrogen atom or a methyl group, each R2 individually represents an oxygen atom or sulfur atom, R3 is a group -CH2-,-C (CH3) 2-,-S-,-SO-, or-SO2-, Xl to X4 individually represent a hydrogen atom, methyl group, or bromine atom, and m and n individually represent a number from 1 to 9; (B) a monofunctional (meth) acrylate represented by the following formula (2), wherein R4 represents a hydrogen atom or a methyl group, R5 represents- (CH2CH2O) p-,- (CH (CH3) CH20) q-, or-CH2CH (OH) CH20- (wherein p and q represent integers from 0 to 10), and Y'to Y3 individually represent a hydrogen atom, a bromine atom, an alkyl group having 1-10 carbon atoms, phenyl group, or-C (CH3) 2C6H5- ; and (C) a photoinitiator.

The present invention further provides a photosensitive resin composition which may comprise, in addition to the components of the above photocurable resin composition, 0.001 to 10 parts by weight of polyoxyalkylene alkyl ether phosphate of the following formula (3) as component (D) for 100 parts by weight of the components (A), (B), and (C),

wherein R6 is an alkyl group or an alkyl-substituted phenyl group with the alkyl group having 1-20 carbon atoms, r is a number from 1 to 15, and A is-OH or R8O (CH2CH (R') O),-, wherein R8 is an alkyl group or an alkyl-substituted phenyl group with the alkyl group having 1-20 carbon atoms, s is a number from 1 to 15, and R7 represents a hydrogen atom or methyl group.

The present invention further provides optical parts comprising a cured product of the above photocurable resin composition.

Preferred Embodiments of the Invention The component (A) used in the photocurable resin composition of the present invention is preferably a urethane (meth) acrylate produced by reacting at least four compounds which preferably comprise a polyether diol compound with a number average molecular weight of 200 to 500 containing a structure selected from the group consisting of a tetramethyleneoxy structure, a propyleneoxy structure, and a 1,2-butyleneoxy structure in the molecule, preferably a diol compound represented by the following formula (1), but other than the above polyether diol compound, an organic polyisocyanate compound, and a hydroxyl group-containing (meth) acrylate.

As examples of the polyether diol compound having a tetramethyleneoxy structure, propyleneoxy structure, or 1,2-butyleneoxy structure in the molecule, polytetramethylene glycol, polypropylene glycol, and poly (1,2)- butylen glycol ; binary copolymers such as a copolymer of tetrahydrofuran and propylene oxide, tetrahydrofuran and 2-methyltetrahydrofuran, tetrahydrofuran and 3-methyltetrahydrofuran, tetrahydrofuran and ethylene oxide, or butene-1- oxide and ethylene oxide; and ternary copolymers such as a copolymer of tetrahydrofuran, butene-oxide, and propylene oxide, propylene oxide, butene-1- oxide, and ethylene oxide, or tetrahydrofuran, butene-1-oxide, and ethylene oxide, can be given. A polyether diol produced by the ring-opening copolymerization of the above ion-polymerizable cyclic compounds and cyclic imines such as ethyleneimine, cyclic lactonic acids such as s-propyolactone and glycolic acid

lactid, or dimethylcyclopolysiloxanes can also be used. The ring-opening copolymers of the ion-polymerizable cyclic compounds may be either a random copolymer or a block copolymer. The polystyrene-reduced number average molecular weight of these polyether diols determined by GPC is preferably from 200 to 500, preferably from 220 to 480, and still more preferably from 240 to 460.

If the number average molecular weight is less than 200, it may be difficult for the cured products to exhibit satisfactory lens properties such as adhesion to substrates, abrasion resistance, and shape restorability. If more than 500, it may be difficult for a lens to maintain the proper shape when a load is applied. As commercially available products of the above polyether diols, PTG250, PTG400 (manufactured by Hodogaya Chemical Co., Ltd.), K-4006, K-4007 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Sunnix PP-400 (manufactured by Sanyo Chemical Industries, Ltd.), and the like can be given.

As examples of the organic polyisocyanate compound used for producing the urethane (meth) acrylate (A), polyisocyanates having an aromatic ring such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylen diisocyanate, 1,4-xylylen diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3'-dimethyl-4,4'- diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'- dimethylphenylene diisocyanate, and 4,4'-biphenylene diisocyanate can be given.

Of these, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylen diisocyanate, and 1,4-xylylen diisocyanate are particularly preferable.

Given as examples of the hydroxyl group-containing (meth) acrylate compound used for the preparation of the urethane (meth) acrylate of component (A) are (meth) acrylate compounds such a compound are 4- hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2- hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, 1,4- butandiol mono (meth) acrylate, 2-hydroxyalkyl (meth) acryloyl phosphate, 4- hydroxycyclohexyl (meth) acrylate, 1,6-hexanediol mono (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolethane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, and (meth) acrylates represented by the following structural formula (4):

wherein R9 represents a hydrogen atom or a methyl group and v is a number from 1 to 15. Compounds obtained by the addition reaction of (meth) acrylic acid and a compound containing a glycidyl group such as alkyl glycidyl ether, allyl glycidyl ether, and glycidyl (meth) acrylate can also be used. These hydroxyl group- containing (meth) acrylates may be used either individually or in combinations of two or more. m and n in the formula (1) represent integers from 0 to 9, and preferably from 1 to 5. As examples of the diol shown by the formula (1), an ethylene oxide (m = n = 1.3) addition product of bisphenol A, ethylene oxide (m = n = 2) addition product of bisphenol A, ethylene oxide (m = n = 5) addition product of bisphenol A, propylene oxide (m = n = 1.1) addition product of bisphenol A, propylene oxide (m = n = 1.5) addition product of bisphenol A, propylene oxide (m = n = 3) addition product of bisphenol A, ethylene oxide (m = n = 2) addition product of bisphenol F, ethylene oxide (m = n = 4) addition product of bisphenol F, propylene oxide (m = n = 2) addition product of bisphenol F, ethylene oxide (m = n = 2) addition product of bisphenol S, propylene oxide (m = n = 2) addition product of bisphenol S, ethylene oxide (m = n = 2) addition product of tetrabromobisphenol A, and the like can be given. The polystyrene-reduced number average molecular weight of the diol shown by the formula (1) is preferably 1000 or less.

As examples of commercially available products of the diol shown by the formula (1), Uniol DA-400, DA-550, DA-700, DB-400, DB-530, DB- 900, DAB-800 (manufactured by Nippon Oil and Fats Co., Ltd.), and the like can be given.

Given as examples of methods of reacting the a polyether diol compound having a structure selected from the group consisting of a tetramethyleneoxy structure, a propyleneoxy structure, and a 1,2-butyleneoxy structure in the molecule (hereinafter may be called simply"a polyether diol"), a diol compound represented by the above formula (1), an organic polyisocyanate compound, and a hydroxyl group-containing (meth) acrylate for producing the urethane (meth) acrylate (A) are: a method of reacting the above polyether diol,

the diol of the formula (1), the organic polyisocyanate compound, and the hydroxyl group-containing (meth) acrylate all together; a method of reacting the polyether diol with the organic polyisocyanate compound, then reacting with the diol of the formula (1), and finally reacting with the hydroxyl group-containing (meth) acrylate ; a method of reacting the diol of the formula (1) with the organic polyisocyanate compound, then reacting with the polyether diol, and finally with the hydroxyl group-containing (meth) acrylate ; a method of reacting a mixture of the polyether diol and the diol of the formula (1) with the organic polyisocyanate compound, and then with the hydroxyl group-containing (meth) acrylate ; a method of reacting the organic polyisocyanate compound with the hydroxyl group-containing (meth) acrylate, reacting with the polyether diol, and finally with the diol of the formula (1); a method of reacting the organic polyisocyanate compound with the hydroxyl group-containing (meth) acrylate, reacting with the diol of the formula (1), and finally with the polyether diol ; and a method of reacting the organic polyisocyanate compound with the hydroxyl group-containing (meth) acrylate, and reacting with a mixture of the polyether diol and the diol of the formula (1). Of these methods, the method of reacting the organic polyisocyanate compound with the hydroxyl group-containing (meth) acrylate, then reacting with the polyether diol, and finally with the diol of the formula (1) is preferable for producing the urethane (meth) acrylate of the present invention.

When producing the urethane (meth) acrylate (A), it is preferable to add the polyether diol, and finally with the diol of the formula (1), organic polyisocyanate compound, and hydroxyl group-containing (meth) acrylate so that the isocyanate groups included in the organic polyisocyanate compound and the hydroxyl groups included in the hydroxyl group-containing (meth) acrylate are respectively 1.1-1.5 equivalents and 0.1-0.5 equivalent for one equivalent of the hydroxyl groups included in the polyether diol and the diol of the formula (1).

The urethane (meth) acrylate (A) most preferably contains the polyether diol and the diol of the formula (1) in the molecule by the reaction with the organic isocyanate compound. In this instance, the polyether diol and the diol of the formula (1) are used preferably at a proportion of 10-70 parts by weight and 30-90 parts by weight. If the urethane (meth) acrylate (A) does not contain either the polyether diol or the diol of the formula (1) in the molecule, the cured product may not satisfy the target characteristics such as a refractive index, modulus of elasticity, adhesion to substrates, and restorability from deformation, and therefore

may not exhibit satisfactory performance as optical parts.

In the reaction of these components for preparing the urethane (meth) acrylate, a urethanization catalyst such as copper naphthenate, cobalt naphthenate, zinc naphthenate, di-n-butyltin dilaurate, triethylamine, and triethylenediamine-2-methyltriethyleneamine is usually used in an amount from 0.01 to 1 wt% of the total weight of the reactant. The reaction is carried out preferably at 10-90°C, and particularly preferably at 30-80°C.

The number average molecular weight of the urethane (meth) acrylate (A) is preferably from 1,000 to 20,000, and particularly preferably from 1,500 to 15,000. If the number average molecular weight of the urethane (meth) acrylate (A) is less than 1,000, the modulus of elasticity of the cured product produced by curing the resin composition may increase extremely, thereby causing a break or crack when used as a lens. If the number average molecular weight exceeds 20,000, handling of the resin composition may become difficult due to the increased viscosity.

The urethane (meth) acrylate of the component (A) preferably contains both the polyether diol having a number average molecular weight of 200 to 500 and containing a tetramethyleneoxy structure in the molecule, and the polyether diol having a number average molecular weight of 200 to 500 and containing a 1,2-butyleneoxy structure in the molecule to obtain cured resin products with satisfactory adhesion to substrates, shape restorability, and breaking resistance. To obtain cured resin products with satisfactory adhesion to substrates, shape restora. bility, and breaking resistance, the urethane (meth) acrylate of the component (A) preferably contains both the polyether diol with a number average molecular weight of 200 to 500 containing a tetramethyleneoxy structure in the molecule, and the polyether diol with a number average molecular weight of 200 to 500 containing a 1,2-butyleneoxy structure in the molecule. Shape restorability of the cured resin products can be improved by using a polyether diol with a number average molecular weight of 200 to 500 containing a tetramethyleneoxy structure in the molecule as the component for the urethane (meth) acrylate (A). Adhesion to substrates of the cured resin products is improved by using a polyether diol with a number average molecular weight of 200 to 500 containing a 1,2-butyleneoxy structure in the molecule as the component for the urethane (meth) acrylate (A). The polyether diol with a number average molecular weight of 200 to 500 containing a tetramethyleneoxy structure

in the molecule and the polyether diol with a number average molecular weight of 200 to 500 containing a 1,2-butyleneoxy structure in the molecule may be used as the components for the urethane (meth) acrylate (A) at any arbitrary ratio without a specific limitations, but giving due consideration to the balance between the required adhesion to substrates and shape restorability.

The urethane (meth) acrylate (A) is added to the resin composition in an amount preferably from 20 to 80 wt%, and still more preferably from 30 to 70 wt%. The lower limit of this range must be observed for providing the cured product with appropriate mechanical properties such as mechanical strength and toughness, properties of preventing a break or crack when used as a lens sheet, and properties of ensuring easy restore of the lens shape when crushed. The upper limit of this range must be observed for preventing the workability or applicability from decreasing due to the increased viscosity of the composition.

The monofunctional (meth) acrylate shown by the formula (2) is preferably used as the component (B) of the photocurable resin composition of the present invention. Examples of the component (B) include phenoxyethyl (meth) acrylate, phenoxy-2-methylethyl (meth) acrylate, phenoxyethoxyethyl (meth) acrylate, 3-phenoxy-2-hydroxypropyl (meth) acrylate, 2-phenylphenoxyethyl (meth) acrylate, 4-phenylphenoxyethyl (meth) acrylate, 3- (2-phenylphenyl-2- hydroxypropyl (meth) acrylate, (meth) acrylate of p-cumylphenol which is reacted. with ethylene oxide, 2-bromophenoxyethyl (meth) acrylate, 2,4- dibromophenoxyethyl (meth) acrylate, 2,4,6-tribromophenoxyethyl (meth) acrylate, and the like. Of these, phenoxyethyl (meth) acrylate, phenoxyethoxyethyl (meth) acrylate, (meth) acrylate of p-cumylphenol reacted with ethylene oxide, 2,4,6-tribromophenoxyethyl (meth) acrylate, and the like are particularly preferable.

As examples of commercially available products of these compounds, ARONIX M110, M101, M5700, TO-1317 (manufactured by Toagosei Co., Ltd.), Viscoat #192, #193, #220, 3BM (manufactured by Osaka Organic Chemical Industry Co., Ltd.), NK Ester AMP-10G, AMP-20G (manufactured by Shin-Nakamura Chemical Co., Ltd.), Light Acrylate PO-A, P-200A, Epoxy Ester M- 600A (manufactured by Kyoeisha Chemical Co., Ltd.), New Frontier PHE, CEA, PHE-2, BR-31, BR-31M, BR-32 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and the like can be given.

The amount of the component (B) added to the composition is

preferably 10-70 wt%, and particularly preferably 20-60 wt%. The lower limit of this range is specified for providing both favourable adhesion to substrates and a sufficient refractive index. The upper limit of this range is specified for obtaining preferred mechanical properties and applicability.

In the present invention, a compound having a (meth) acryloyl group or a vinyl group other than the component (B) can be used as an optional component (hereinafter referred to as"unsaturated monomer"). As the unsaturated monomer, a monofunctional monomer and a polyfunctional monomer can be used. As examples of the monofunctional monomer, a vinyl monomer such as N-vinylpyrrolidone, N-vinylcaprolactam, vinylimidazole, and vinylpyridine, isobornyl (meth) acrylate, bornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, 6-butylcyclohexyl (meth) acrylate, acryloylmorpholine, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, amyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, methoxyethylene glycol (meth) acrylate, ethoxyethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, diacetone (meth) acrylamide, isobutoxymethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, t- octyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, 7-amino-3,7-dimethyloctyl (meth) acrylate, N, N- diethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, hydroxy butyl ether, lauryl vinyl ether, cetyl vinyl ether, 2-ethylhexyl vinyl ether, and monofunctional monomers shown by formulas (5) and (6) can be given:

wherein R10 is a hydrogen atom or a methyl group, R"is an alkylen group having 2 to 8 carbon atoms, and w is a number from 1 to 8. wherein R12 and R'3 are individually a hydrogen atom or a methyl group, and R14 is an alkylen group having 2 to 8 carbon atoms, and x is a number from 1 to 8.

As examples of commercially available products of the monofunctional monomers, Aronix M111, M113, M117 (manufactured by Toagosei Co., Ltd.), LA, IBXA, Viscoat #190, #2000 (manufactured by Osaka Organic Chemical Industry Co., Ltd.), Light Acrylate EC-A, PO-A, NP-4EA, NP-8EA, HOA-MPL (manufactured by Kyoeisha Chemical Co., Ltd.), KAYARAD TC110S, R629, R644 (manufactured by Nippon Kayaku Co., Ltd.), FA-51 1A, 512A, 513A (manufactured by Hitachi Chemical Co., Ltd.), VP (manufactured by BASF), ACMO, DMAA, DMAPAA (manufactured by KOHJIN Co., Ltd.), and the like can be given.

As examples of the polyfunctional monomers, acrylate compounds such as trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropanetrioxyethyl (meth) acrylate, tris (2- hydroxyethyl) isocyanurate tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate di (meth) acrylate, bis (hydroxymethyl) tricyclodecane di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, di (meth) acrylate of a diol which is an addition product of polyethylene oxide or propylene oxide to bisphenol

A, di (meth) acrylate of a diol which is an addition product of ethylene oxide or propylene oxide to hydrogenated bisphenol A, epoxy (meth) acrylate produced by adding (meth) acrylic acid to a reaction product of diglycidyl ether and bisphenol A, and triethylene glycol divinyl ether can be given.

As examples of commercially available products of the polyfunctional monomers, Yupimer UV SA1002, SA2007 (manufactured by Mitsubishi Chemical Corp.), Viscoat#195, #230, #215, #260, #335HP, #295, #300, #360, #700, GPT, 3PA (manufactured by Osaka Organic Chemical Industry Co., Ltd.), Light Acrylate 4EG-A, 9EG-A, NP-A, DCP-A, BP-4EA, BP-4PA, TMP-A, PE-3A, PE-4A, DPE-6A (manufactured by Kyoeisha Chemical Co., Ltd.), KAYARAD PET-30, TMPTA R-604, DPHA, DPCA-20,-30,-60,-120, HX-620, D- 310, D-330 (manufactured by Nippon Kayaku Co., Ltd.), Aronix M-208, M-210, M- 215, M-220, M-240, M-305, M-309, m-310, M-315, M-325 M-400 (manufactured by Toagosei Co., Ltd.), Ripoxy VR-77, VR-60, VR-90 (manufactured by Showa Highpolymer Co., Ltd.) and the like can be given.

The photocurable resin composition of the present invention is cured by radiation. Radiation used herein includes ionizing radiation such as infrared rays, visible rays, ultraviolet rays, X-rays, electron beams, a-rays, (3-rays, y-rays, and the like. The photoinitiator which is the component (C) is required for curing the resin composition of the present invention and a photosensitizer is optionally added. As the photoinitiator, any compound which decomposes upon irradiation and generate radicals to initiate the polymerization can be used.

Examples of such compounds include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'- dimethoxybenzophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1- (4-isopropylphenyl)-2- hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl]-2-morpholino-propan-1-one, 2,4,6- trimethylbenzoyl diphenylphosphine oxide, and bis- (2, 6-dimethoxybenzoyl)-2, 4,4- trimethylpentylphosphine oxide.

As examples of commercially available products of the

photoinitiator, Irgacure184, 369,651,500,819,907,784,2959, CGI-1700, CGI- 1750, CGI-1850, CG24-61, Darocur 1116,1173 (manufactured by Ciba Specialty Chemicals Co., Ltd.), Lucirin TPO, LR8893, LR8970 (manufactured by BASF), Ubecryl P36 (manufactured by UCB), and the like can be given.

As examples of the photosensitizer, triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4- dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4- dimethylaminobenzoate, and the like can be given. As examples of commercially available products of the photosensitizer, Ubecryl P102,103,104,105 (manufactured by UCB), and the like can be given.

The optimum amount of the photoinitiator used to cure the resin composition of the present invention is from 0.01 to 10 wt%, and preferably from 0.5 to 7 wt% of the total amount of the composition. The above upper limit is desirable in view of ensuring superior curing characteristics of the composition, mechanical and optical characteristics of cured products, and handling easiness; and the lower limit is desirable for preventing decrease in the curing speed.

A heat-polymerization initiator can be optionally added when curing the resin composition of the present invention. Peroxides and azo compounds can be given as examples of preferable heat-polymerization initiators.

Specific examples include benzoyl peroxide, t-butyl peroxybenzoate, azobisisobutyronitrile, and the like.

It is desirable to add a polyoxyalkylene alkyl ether phosphate of the above formula (3) to the resin composition of the present invention as the component (D) to improve releasability from a mold during continuous manufacture of cured products. Polyoxyethylene alkyl ether phosphate, polyoxypropylene alkyl ether phosphate, polyoxyethylene alkyl-substituted phenyl ether phosphate, olyoxypropylene alkyl-substituted phenyl ether phosphate, and the like can be given as polyoxyalkylene alkyl ether phosphates used as the component (D). Given as specific examples of commercially available products of polyoxyalkylene alkyl ether phosphate used as the component (D) are Plysurf AL, A-208S, A-208B, A208F, A-219B, M208F, A-215C, A-212C, A-217E (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Antox EHD-200, Newcol 1000FCP, 565-PS, 1120-PS, Paracol OP (manufactured by Nippon Nyukazai Co., Ltd.), and the like.

The amount of polyoxyalkylene alkyl ether phosphate used as

the component (D) in the resin composition of the present invention is preferably from 0.001 to 10 parts by weight, and particularly preferably from 0.01 to 2 parts by weight, for 100 parts by weight of the components (A), (B), and (C). If less than 0.001 parts by weight, releasability from metal molds during continuous manufacture may be insufficient; if more than 10 parts by weight, liquid bleeds may appear on the surface of cured products, impairing external appearance of final products and performance of lenses.

Curable oligomers or polymers other than the above components may be added to the resin composition of the present invention insofar as the characteristics of the resin composition are not adversely affected.

As examples of such curable oligomers or polymers, polyurethane (meth) acrylate other than the component (A), polyester (meth) acrylate, epoxy (meth) acrylate, polyamide (meth) acrylate, siloxane polymers having a (meth) acryloyloxy group, and reactive polymers produced by reacting a copolymer of glycidyl methacrylate and other polymerizable monomers with (meth) acrylic acid can be given.

In addition to the above components, additives such as antioxidants, UV absorbers, light stabilizers, silane coupling agents, coating surface improvers, heat-polymerization inhibitors, leveling agents, surfactants, coloring agents, preservatives, plasticizers, lubricants, solvents, fillers, aging preventives, wettability improvers, and the like can be added as required.

Examples of antioxidants include Irganox1010, 1035,1076,1222 (manufactured by Ciba Specialty Chemicals Co., Ltd.), Antigene P, 3C, FR, Sumilizer GA-80 (manufactured by Sumitomo Chemical Industries Co., Ltd.), and the like ; examples of UV absorbers include Tinuvin P, 234,320,326,327,328,329,213 (manufactured by Ciba Specialty Chemicals Co., Ltd.), Seesorb 102,103,110, 501,202,712,704 (manufactured by Sypro Chemical Co., Ltd.), and the like ; examples of light stabilizers include Tinuvin 292,144,622LD (manufactured by Ciba Specialty Chemicals Co., Ltd.), Sanol LS770 (manufactured by Sankyo Co., Ltd.), Sumisorb TM-061 (manufactured by Sumitomo Chemical Industries Co., Ltd.), and the like ; examples of silane coupling agents include y- aminopropyltriethoxysilane, y-mercaptopropyltrimethoxy-silane, and y- methacryloxypropyltrimethoxysilane, and commercially available products such as SH6062, SH6030 (manufactured by Toray-Dow Corning Silicone Co., Ltd.), and KBE903, KBE603, KBE403 (manufactured by Shin-Etsu Chemical Co., Ltd.);

examples of coating surface improvers include silicone additives such as dimethylsiloxane polyether and commercially available products such as DC-57, DC-190 (manufactured by Dow-Corning), SH-28PA, SH-29PA, SH-30PA, SH-190 (manufactured by Toray-Dow Corning Silicone Co., Ltd.), KF351, KF352, KF353, KF354 (manufactured by Shin-Etsu Chemical Co., Ltd.), and L-700, L-7002, L- 7500, FK-024-90 (manufactured by Nippon Unicar Co., Ltd.).

The resin composition of the present invention is manufactured by mixing the above components using a conventional method. Viscosity of the resin composition of the present invention thus prepared is usually from 200 to 50,000 mPa s/25°C, and preferably from 500 to 30,000 mPa s/25°C. If the viscosity is too high, uneven coating or a crinkle occurs or the objective lens thickness cannot be secured, thereby resulting in inadequate lens performance. If the viscosity is too low, on the other hand, it is difficult to control the lens thickness and therefore to manufacture lenses with a uniform thickness.

It is particularly preferable that the cured product prepared by curing the resin composition of the present invention by radiation have the following properties.

The cured product produces a temperature dependency curve of a loss tangent having at least two peaks or shoulders at a temperature range between-150 and 100°C when an oscillation frequency of 10 Hz is applied using a dynamic viscoelasticity measuring device. If a translucent screen such as a lens sheet is formed from the resin composition of which the cured product satisfies this property, such a translucent screen exhibits superior adhesion to substrates, shape restorability, and moderate mechanical properties. Therefore, the lens projection is protected from abrasion or fracture, or even if crushed, the original shape can be immediately restored.

The refractive index of the cured product at 25°C is preferably 1.54 or more, and still more preferably 1.55 or more. If the refractive index is less than 1.54, a translucent screen formed from the resin composition may exhibit insufficient frontal brightness.

Examples The present invention will be described in more detail by examples, which are not intended to be limiting of the present invention.

Examples 1-6 and Comparative Examples 1-3 Synthesis Example 1 of urethane (meth) acrylate A reaction vessel equipped with a stirrer was charged with 29.6 parts by weight of 2,4-tolylene diisocyanate, 0.08 part by weight of di-n-butyltin dilaurate, and 0.02 part by weight of 2,6-di-t-butyl-p-cresol. The mixture was cooled to 5-10°C. 18.9 parts by weight of 2-hydroxy-3-phenyloxypropyl acrylate was added dropwise while stirring so as to maintain the temperature at 30°C or lower. After the addition, the mixture was allowed to react at 30°C for one hour.

34.2 parts by weight of polytetramethylene glycol with a number average molecular weight of 402 was then added and the mixture was reacted at 50°C for one hour. After the addition of 17.2 parts by weight of an ethylene oxide addition product of bisphenol A (m = n = 2.0), the mixture was reacted at 50-70°C for two hours. The reaction was terminated when the residual isocyanate was 0.1 part by weigh or less. The resulting urethane acrylate is referred to as"A-1".

Synthesis Example 2 of urethane (meth) acrylate A reaction vessel equipped with a stirrer was charged with 30.1 parts by weight of 2,4-tolylene diisocyanate, 0.08 part by weight of di-n-butyltin dilaurate, and 0.02 part by weight of 2, 6-di-t-butyl-p-cresol. The mixture was cooled to 5-10°C. 19.2 parts by weight of 2-hydroxy-3-phenyloxypropyl acrylate was added dropwise while stirring so as to maintain the temperature at 30°C or lower. After the addition, the mixture was allowed to react at 30°C for one hour.

33.1 parts by weight of poly (1,2)-butylene glycol with a number average molecular weight of 383 was then added and the mixture was reacted at 50°C for one hour.

After the addition of 17.6 parts by weight of an ethylene oxide addition product of bisphenol A (m = n = 2.0), the mixture was reacted at 50-70°C for two hours. The reaction was terminated when the residual isocyanate was 0.1 part by weigh or less. The resulting urethane acrylate is referred to as"A-2".

Synthesis Example 3 of urethane (meth) acrylate A reaction vessel equipped with a stirrer was charged with 29.8 parts by weight of 2,4-tolylene diisocyanate, 0.08 part by weight of di-n-butyltin dilaurate, and 0.03 part by weight of 2,6-di-t-butyl-p-cresol. The mixture was cooled to 5-10°C. 19.0 parts by weight of 2-hydroxy-3-phenyloxypropyl acrylate was added dropwise while stirring so as to maintain the temperature at 30°C or

lower. After the addition, the mixture was allowed to react at 30°C for one hour.

Next, a homogeneous mixture of 17.2 parts by weight of polytetramethylene glycol with a number average molecular weight of 402 and 16.4 parts by weight of poly (1,2)-butylene glycol with a number average molecular weight of 383 was added and the mixture was reacted at 50°C for one hour. After the addition of 17.4 parts by weight of an ethylene oxide addition product of bisphenol A (m = n = 2.0), the mixture was reacted at 50-70°C for two hours. The reaction was terminated when the residual isocyanate was 0.1 part by weigh or less. The resulting urethane acrylate is referred to as"A-3".

Synthesis Example 4 of urethane (meth) acrylate A reaction vessel equipped with a stirrer was charged with 29.6 parts by weight of 2,4-tolylene diisocyanate, 0.08 part by weight of di-n-butyltin dilaurate, and 0.02 part by weight of 2,6-di-t-butyl-p-cresol. The mixture was cooled to 5-10°C. 18.9 parts by weight of 2-hydroxy-3-phenyloxypropyl acrylate was added dropwise while stirring so as to maintain the temperature at 30°C or lower. After the addition, the mixture was allowed to react at 30°C for one hour.

51.5 parts by weight of polytetramethylene glycol with a number average molecular weight of 402 was then added and the mixture was reacted at 50-70°C for two hours. The reaction was terminated when the residual isocyanate was 0.1 part by weigh or less. The resulting urethane acrylate is referred to as"A-4".

Synthesis Comparative Example 1 of urethane (meth) acrvlate A reaction vessel equipped with a stirrer was charged with 42.88 parts by weight of 2,4-tolylene diisocyanate, 0. 08 part by weight of di-n-butyltin dilaurate, and 0.03 part by weight of 2,6-di-t-butyl-p-cresol. The mixture was cooled to 5-10°C. 19.08 parts by weight of 2-hydroxyethyl acrylate was added dropwise while stirring so as to maintain the temperature at 30°C or lower. After the addition, the mixture was allowed to react at 30°C for one hour. 5.09 parts by weight of ethylene glycol was then added and the mixture was reacted for one hour. After the addition of 32.86 parts by weight of an ethylene oxide addition product of bisphenol A (m = n = 2.0), the mixture was reacted at 50-70°C for two hours. The reaction was terminated when the residual isocyanate was 0.1 part by weigh or less. The resulting urethane acrylate is referred to as"A-5".

Synthesis Comparative Example 2 of urethane (meth) acrvlate A reaction vessel equipped with a stirrer was charged with 15.4 parts by weight of 2,4-tolylene diisocyanate, 0.08 part by weight of di-n-butyltin dilaurate, and 0.02 part by weight of 2,6-di-t-butyl-p-cresol. The mixture was cooled to 5-10°C. 13.1 parts by weight of 2-hydroxy-3-phenyloxypropyl acrylate was added dropwise while stirring so as to maintain the temperature at 30°C or lower. After the addition, the mixture was allowed to react at 30°C for one hour.

59.4 parts by weight of polytetramethylene glycol with a number average molecular weight of 2018 was then added and the mixture was reacted at 50°C for one hour. After the addition of 12.0 parts by weight of an ethylene oxide addition product of bisphenol A (m = n = 2.0), the mixture was reacted at 50-70°C for two hours. The reaction was terminated when the residual isocyanate was 0.1 part by weigh or less. The resulting urethane acrylate is referred to as"A-6".

Synthesis Comparative Example 3 of urethane (meth) acrvlate A reaction vessel equipped with a stirrer was charged with 36.12 wt% of 2,4-tolylene diisocyanate, 0.08 wt% of di-n-butyltin dilaurate, and 0.03 wt% of 2,6-di-t-butyl-p-cresol. The mixture was cooled to 5-10°C. To the mixture was added 23.04 wt% of 2-hydroxy-3-phenyloxypropyl acrylate dropwise while stirring so as to maintain the temperature at 30°C or lower. After the addition, the mixture was reacted for one hour at 30°C. The mixture was further added with 19.96 wt% of tripropylene glycol (Mw=192. 3) and 20.76 wt% of and ethylene oxide addition product of bisphenol A (m=n=2.0), and the mixture was reacted at 50-70°C for two hours. The reaction was terminated when the residual isocyanate was 0.1 wt% or less. The resulting urethane acrylate is referred as"A-7".

Example 1 A reaction vessel equipped with a stirrer was charged with 20 parts by weight of"A-1"as the component (A), 36 parts by weight of phenoxyethyl acrylate (New Frontier PHE manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as the component (B), 3.5 parts by weight of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184 manufactured by Ciba Specialty Chemicals Co.) as the component (C), 0.2 part by weight of Plysurf A-208F (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as the component (D), 12 parts by weight of an ethylene oxide addition

compound of bisphenol A diacrylate (Viscoat #700 manufactured by Osaka Organic Chemical Industry, Ltd.), 6 parts by weight of tetraethylene glycol diacrylate (Light Acrylate 4EG-A manufactured by Kyoeisha Chemical Co., Ltd.), 2 parts by weight of SH-190 (a coating surface improver, manufactured by Toray- Dow Corning Silicone Co.), and 0.3 part by weight of Irganox 1035 (an antioxidant, manufactured by Ciba Specialty Chemicals Co.) as other components. The mixture was stirred for one hour while maintaining the liquid temperature at 50- 60°C to obtain a liquid curable resin composition with a viscosity of 2,800 mPa-s/25°C.

As for Examples 2-6 and Comparative Examples 1-3, liquid resin compositions were obtained by charging the reaction vessel with the components shown in Table 1 and reacting the components.

Evaluation methods Test specimens were prepared using the liquid curable resin compositions obtained in the examples according to the method described below.

The viscosity, refractive index, adhesion to substrates, abrasion resistance, breaking resistance, and shape restorability of the test specimens were measured according to the following methods.

(1) Viscosity measurement: The viscosity of the liquid curable resin composition at 25°C was measured using a rotational viscometer according to JIS K7117.

(2) Preparation of test specimens for measurement of refractive index: The liquid curable resin composition was applied onto a glass plate to a thickness of about 200 um using a 15 mill applicator bar. The composition was irradiated with ultraviolet rays at a dose of 1.0 J/cm2 in air to obtain a cured film. The cured film was removed from the glass plate for use as a test specimen.

(3) Measurement of refractive index: The refractive index at 25°C of the test specimen prepared above was measured according to JIS K7105 using an Abbe's refractometer

(manufactured by Atago Co., Ltd.).

(4) Preparation of test specimens for measurement of adhesion to substrates, abrasion resistance, and breaking resistance: Liquid curable resin compositions shown in Table 1 were fed to the space between a Fresnel lens mold and a PMMA substrate (10 cm x 10 cm) with a thickness of 2 mm, and the PMMA substrate was pressed to prepare resin composition layers with a uniform thickness. The resin layer was cured by irradiating with ultraviolet rays at a dose of 1.0 J/cm2 from the side of the substrate. The cured resin (hereinafter referred to as"lens substrate") was removed from the mold by hand.

(5) Adhesion to substrates: Lens substrates removed from the above lens molds were evaluated by measuring adhesivness with the MS substrates by a cross cut peeling test according to JIS K5400. A lens for which the square was not peeled from the MS substrate but adhered perfectly to the MS substrate was rated as AAA, a lens for which part of the squares was peeled from the MS substrate was rated as BBB, and a lens for which all the squares were peeled from the MS substrate was rated as CCC.

(6) Abrasion resistance : The lens substrate removed from the mold was placed on a plane with the lens surface upside, on which a PMMA lenticular lens (radius 0.5 mm, pitch 0.7 mm, 10 cm x 10 cm, manufactured by Nihon Tokushu Kougaku Jushi Co., Ltd.) was layered with the hill of the lenses perpendicularly crossing.

Then, a load of 500 g was applied. The surface conditions of the lens was observed after oscillating the lens substrate for 5 minutes at the oscillating cycle resulting in a back-and-forth movement twice a second at an interval of 4 cm at- 20°C. A lens with no abrasion or broken parts was rated as AAA, a lens with some abrasion or broken parts was rated as BBB, and a lens with abrasion or broken parts over the entire surface was rated as CCC.

(7) Breaking resistance and shape restorability : The lens substrate removed from the mold was layered on the

same PMMA lenticular lens as above with the hills of the lenses perpendicularly crossing. A load of 1 kg was applied for one hour at a room temperature. The Fresnel lens was removed to inspect the shape by microscope. A lens with deformation or breaking clearly observed was rated as CCC, a lens with a slight mark of the hill of the lenticular lens observed on the surface was rated as BBB, and a lens with no abnormality nor a mark of the hill of the lenticular lens observed was rated as AAA (8) Shape restorabilitv A metal ball indenter with a diameter of 0.4 mm was pressed into the lens surface of the lens substrate removed from the lens mold with a 30 g load for one minute. The period of time required for the ball mark on the lens surface to disappear was measured at 23°C. A lens for which the ball mark disappeared within 5 minutes was rated as AAA, a lens for which the ball mark disappeared within 10 minutes was rated as BBB, a lens for which the ball mark disappeared later than 10 minutes but within one hour was rated CCC, and a lens for which the ball mark did not disappear after one hour was evaluated as DDD.

[Table 1] Example | Comparative example 1 2 3 4 5 6 1 2 3 Component(A) A-1 20 50 A-2 20 50 A-3 40 40 A-4 40 Comparative Component (A) A-5 40 A-6 50 A-7 40 Component (B) B-1 36 36 15 36 15 36 B-2 25 15 15 B-3 9. 5 36 36 Component (C) C-1 3.5 3.5 2 3.5 3.5 3.5 3.5 C-2 4 4 Component (D) D-1 0. 2 0.2 0.5 0.1 0.2 0.2 0.2 0.1 0.2 Other components E-1 12 12 7 12 12 7 12 E-2 6 6 10 6.5 6 6 6.5 6 F-1 0.3 0.3 0.3 0.4 0.3 0.3 0.3 0.4 0.3 F-2 2 2 2.7 2 2 2 2 2 2 LiquidProperties Viscosity (mPa s/25°C) 2800 3000 1900 5400 1300 2600 1600 14000 2200 Example Comparative example 1 2 3 4 5 6 1 2 3 Cured product properties Refractive index (ND25) 1.552 1.552 1.558 1.555 1.526 1.537 1.560 1.551 1.555 Adhesion to substrates AAA AAA BBB AAA AAA BBB CCC AAA BBB Abrasion resistance AAA AAA AAA AAA AAA AAA CCC BBB CCC Breaking resistance AAA AAA AAA AAA BBB AAA AAA CCC BBB Shape restorability AAA AAA AAA BBB CCC DDD DDD BBB CCC

The components shown in Table 1 were as follows.

Component (B): B-1: Phenoxyethyl acrylate ("New Frontier PHE"manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) B-2: Acrylate of p-cumylphenol to which 2 mols of ethylene oxide was added (Mn = 354,"ARONIX M110"manufactured by Toagosei Co., Ltd.) B-3: Isobornyl acrylate ("IBXA"manufactured by Osaka Organic Chemical Industry Co., Ltd.) Component (C): C-1 : 1-Hydroxycyclohexyl phenyl ketone (Irgacure 184 manufactured by Ciba Specialty Chemicals Co.) C-2: 2-Hydroxy-2-methyl-1-phenyl-propan-1-one ("Darocur 1173"manufactured by Ciba Specialty Chemicals Co., Ltd.) Component (D): D-1: Polyoxyalkylene alkyl ether phosphate ("Plysurf A-208"manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Other components: E-1: Diacrylate of diol of bisphenol A to which 4 mols of ethylene oxide was added (Mn = 512,"Viscoat 700"manufactured by Osaka Organic Chemical Industry Co., Ltd.) (Mn indicates a polystyrene-reduced number average molecular weight determined by a GPC method) E-2: Ethylene glycol diacrylate ("Light Acrylate 4EGA"manufactured by Kyoeisha Chemical Co., Ltd.) F-1: Thiodiethylenebis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate] ("Irganox 1035FF"manufactured by Ciba Specialty Chemicals Co., Ltd.) F-2: Coating surface improver ("SH-190"manufactured by Toray-Dow Corning Silicone Co., Ltd.)

Preferable embodiments of the present invention are as follows.

1. The photocurable resin composition comprising the component (A) in the amount of 20-80 wt%.

2. The photocurable resin composition comprising the component (B) in the amount of 10-70 wt%.

3. The photocurable resin composition comprising the component (C) in the amount of 0.01-10 wt%.

4. The photocurable resin composition having viscosity of 500-30,000 mua-s at 25°C.

Effect of the Invention The liquid curable resin composition of the present invention provides a cured product exhibiting a high refractive index, superior adhesion to the substrate, restorability, and abrasion resistance. Therefore the resin composition is suitable for manufacturing optical parts such as a lens sheet.