DISPERSIONS OF CARBON BLACK IN ALKYLENE GLYCOL AND IN SITU POLYMERIZATION OF POLYESTER THEREWITH

BACKGROUND OF THE INVENTION

1. Field of the Invention.

[0001] This invention relates to high temperature stable organic dispersions of chemically treated carbon black and their use in preparation of filled polymer fibers.

2, Description of the Related Art.

[0002] Fiber manufacturers are seeking alternatives to bath dying processes for coloring polyester fiber. Carbon black can be used as an alternative to organic dyes. The pigment can be blended directly with virgin polyester and then spun into fiber. Alternatively, the pigment can be blended with polymer to form a masterbatch. The masterbatch can then be combined with additional unfilled polymer and spun into fiber.

[0003] It is desirable to have an even more economical method of preparing carbon black-filled polyester fiber.

SUMMARY OF THE INVENTION

[0004] In one embodiment, a carbon black dispersion comprises a diol selected from an alkylene diol having 2-12 carbon atoms, cycloaliphatic diol having 6-24 carbon atoms, and an aromatic diol having 6-24 carbon atoms; 15-25 % by weight of a modified carbon black, the modified carbon black having a BET surface area between 25 and 180 m ² /g as measured prior to treatment, the modified carbon black modified with a treating agent comprising an organic group and a sulfonic acid group at a treating agent concentration of from 1.0 to 4.0 pmol/m ² based on nitrogen surface area (BET); and polyvinylpyrrolidone in an amount from 0 to 0.2: 1 with respect to the modified carbon black. The carbon black dispersion contains less than 2.5 wt% water and D99 of the carbon black dispersion is less than 1 micron.

[0005] The diol may be ethylene glycol and may contain less than lwt% water. The modified carbon black may have attached phenylsulfonic acid groups. Following incubation at 150°C for two hours, D99 of the dispersion may be less than 1 micron. The polyvinylpyrrolidone may be the only dispersant. The polyvinylpyrrolidone may have a number average molecular weight of 3000-80000 g/mol, for example 5000 to 30000 g/mol or 10,000 to 15000 g/mol.

[0006] In another embodiment, a method of making polyester includes forming a pigmented mixture by combining the carbon black dispersion with either A) a diacid selected from an aromatic dicarboxylic acid having 6 to 24 carbon atoms, a cycloaliphatic dicarboxylic acid having 6 to 24 carbon atoms, and an alkane dicarboxylic acid having 2 to 12 carbon atoms or B) a partially polymerized mixture of Bl) a diacid selected from an aromatic dicarboxylic acid having 6 to 24 carbon atoms, a cycloaliphatic dicarboxylic acid having 6 to 24 carbon atoms, and an alkane dicarboxylic acid having 2 to 12 carbon atoms and B2) a diol selected from an alkylene diol having 2-12 carbon atoms, cycloaliphatic diol having 6-24 carbon atoms, and an aromatic diol having 6-24 carbon atoms. The pigmented mixture is allowed to polymerize to form a polyester. The diacid may be terephthalic acid, and the polyester may be polyethylene terephthalate. The method may further comprise cutting the polyester into chips. The resulting polyester chips may include 15-30 wt% of the modified carbon black or 0.5-3 wt% of the modified carbon black, for example, from 0.5-30 wt% of the modified carbon black.

[0007] In another embodiment, polyester chips include 0.5-3% by weight of a modified carbon black, the modified carbon black having a BET surface area between 25 and 180 m ² /g as measured prior to treatment, the modified carbon black modified with a treating agent comprising an organic group and a sulfonic acid group at a treating agent concentration of from 1.0 to 4.0 pmol/nf based on nitrogen surface area (BET); and polyvinylpyrrolidone in an amount from 0 to 0.2: 1 with respect to the modified carbon black. The polyester may be polyethylene terephthalate and may have a molecular weight Mn of 17000-25000.

[0008] In another embodiment, polyester fiber includes a modified carbon black modified with a treating agent comprising an organic group and a sulfonic acid group at a treating agent concentration of from 1.0 to 4.0 pmol/m ² based on nitrogen surface area (BET), wherein the polyester fiber has ajetness L* of 11-18 and either or both of a fiber tenacity of 2.0-3.5 cN/dtex and an elongation at break of 10-30%. Preferably, the modified carbon black has a BET surface area between 25 and 180 m ² /g as measured prior to treatment [0009] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the present invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWING

[0010] The invention is described with reference to the several figures of the drawing, in which, Figures 1, 2, 3, 4, and 5 are graphs showing the variation of storage modulus with angular frequency for ethylene glycol dispersions of various surface treated carbon blacks.

DETAILED DESCRIPTION OF THE INVENTION

[0011] A carbon black dispersion comprises a diol selected from an alkylene diol having 2-12 carbon atoms, cycloaliphatic diol having 6-24 carbon atoms, and an aromatic diol having 6-24 carbon atoms; 15-25 % by weight of a modified carbon black, the modified carbon black having a BET surface area between 25 and 180 m ² /g as measured prior to treatment, the modified carbon black modified with a treating agent comprising an organic group and a sulfonic acid group at a treating agent concentration of from 1.0 to 4.0 pmol/m ² based on nitrogen surface area (BET); and polyvinylpyrrolidone in an amount from 0 to 0.2: 1 with respect to the modified carbon black. The carbon black dispersion contains less than 2.5 wt% water and D99 of the carbon black dispersion is less than 1 micron.

[0012] Compared to conventional pigments, the chemically treated carbon black products enable higher loadings of pigment to be incorporated into the organic solvent. This in turn allows greater amounts of carbon black to be incorporated into polyester fibers, providing higher jetness, even in finer filaments. Moreover, because the chemically treated carbon black is predispersed in the solvent, the final polymer product exhibits improved carbon black dispersion. This allows fibers to be drawn out to greater lengths without breaking.

[0013] Preferably, the carbon black dispersion is stable after exposure to high temperature. High temperature stability of the dispersion provides several advantages. For example, it is desirable that the dispersion be stable under the high temperature conditions used to produce polyesters. In some embodiments, D99 of the dispersion is less than 1.0 microns after incubation at 150 °C for two hours. [0014] The chemically treated carbon black products may be present in the dispersion in an amount of at least 18% by weight, for example, from 20-25% by weight. Lower amounts of carbon black may be used as well. One of skill in the art will recognize that the amount of chemically treated carbon black in the polymer produced with the carbon black dispersion will depend in part on the loading of chemically treated carbon black in the dispersion as well as the amount of dispersion employed in the polymerization process.

[0015] Suitable carbon blacks are known to those skilled in the art and include channel blacks, furnace blacks, gas blacks, and lamp blacks. Carbon blacks from a variety of suppliers can be used. Some commercially available carbon blacks are sold under the Regal®, Black Pearls®, Elftex®, Monarch®, Mogul®, Spheron®, Sterling®, and Vulcan® trademarks and are available from Cabot Corporation. Other commercially available carbon blacks include but are not limited to carbon blacks sold under the Raven®, Statex®, Fumex®, and Neotex® trademarks, the CD and HV lines available from Columbian Chemicals, and the Corax®, Durax®, Ecorax®, Printex®, and Purex® products available from Orion Engineered Carbons. Furnace blacks are preferred for use with the embodiments provided herein. For preparation of polyester fiber as described elsewhere herein, it may be desirable to use carbon blacks particularly suited for use in fibers, such as Elftex 570, Regal 660, and Black Pearls 5550, 4560i, 5160, 3560, and 5560 carbon blacks from Cabot Corporation, and Printex L6 SQ and alpha SQ and Arosperse® 11, 138, and 26 carbon blacks from Orion Engineered Carbons.

[0016] The carbon blacks described herein can exhibit a specific range of nitrogen surface area (BET, measured according to ASTM D6556). As used herein, the BET surface area of a chemically treated carbon black is the surface area of the carbon black prior to the modification. In some embodiments, the carbon blacks that are chemically treated have a BET between 25 m ² /g and 180 m ² /g, between 30 m ² /g and 150 m ² /g, or between 50 m ² /g and 125 m ² /g. If the surface area of the carbon black is too high, then the carbon black will be difficult to disperse, even with the levels of surface treatment specified herein. In addition, the viscosity of the dispersion will be higher at a given solids loading, and/or the dispersion may display gel -like behavior under shear (i.e., low dependence of storage modulus on angular frequency). [0017] The chemically treated carbon black can have a wide variety of primary particle sizes known in the art. For example, the carbon black may have a primary particle size of from 5 nm to 100 nm, including 10 nm to 80 nm and 15 nm to 50 nm. In some embodiments, the carbon black may have a primary particle size of less than 200, less than 100 or less than 75 nm. In addition, the carbon black can also have a wide range of values of OAN (oil adsorption number, measured according to ASTM D2414), which is a measure of the structure or branching of the pigment. For example, before surface modification, the carbon black may have an OAN value of from 25 to 250 mL/lOOg, for example, from 30 to 150 mL/lOOg or from 50 to 100 mL/lOOg.

[0018] Alternatively, the chemically treated carbon black may be prepared by any method known to those of skill in the art such that sulfonic acid groups are attached to the pigment. For example, sulfonic acid groups can be attached to carbon blacks using methods such as diazonium chemistry, azo chemistry, peroxide chemistry, sulfonation and cycloaddition chemistry. The chemically treated carbon black may be prepared using any method known to those skilled in the art such that organic chemical groups are attached to the pigment. For example, the chemically treated pigments can be prepared using the methods described in U.S. Patent Nos. 5,554,739; 5,707,432; 5,837,045; 5,851,280; 5,885,335; 5,895,522; 5,900,029; 5,922,118; 6,042,643 and 6,337,358, the descriptions of which are fully incorporated herein by reference. Such methods provide for a more stable attachment of organic groups onto the carbon black compared to dispersant type methods, which use, for example, polymers and/or surfactants. Other methods for preparing the chemically treated carbon blacks include reacting a carbon black having available functional groups with a reagent comprising the organic group, such as described in, for example, U.S. Patent No. 6,723,783, which is incorporated in its entirety by reference herein. Such functional pigments may be prepared using the methods described in the references incorporated above. In addition, chemically treated carbon blacks containing attached functional groups may also be prepared by the methods described in U.S. Patent Nos. 6,831,194 and 6,660,075, U.S. Patent Publication Nos. 2003-0101901 and 2001-0036994, Canadian Patent No. 2,351,162, European Patent No. 1 394 221, and PCT Publication No. WO 04/63289, as well as in N. Tsubokawa, Polym. Sci., 17:417, 1992, each of which is also incorporated in their entirety by reference herein. [0019] Diazonium processes disclosed in one or more of these incorporated references can be adapted to provide a reaction of at least one diazonium salt with a carbon black pigment such as a raw or oxidized organic black pigment that has not yet been surface chemically treated with attachment groups. A diazonium salt is an organic compound having one or more diazomum groups. In some processes, the diazonium salt may be prepared prior to reaction with the organic black pigment material or, more preferably, generated in situ using techniques such as described in the cited references. In situ generation also allows the use of unstable diazonium salts such as alkyl diazonium salts and avoids unnecessary handling or manipulation of the diazonium salt. In some processes, both nitrous acid and the diazonium salt can be generated in situ.

[0020] A diazonium salt, as is known in the art, may be generated by reacting a primary amine, a nitrite and an acid. The nitrite may be any metal nitrite, preferably lithium nitrite, sodium nitrite, potassium nitrite, or zinc nitrite, or any organic nitrite such as for example isoamylnitrite or ethylnitrite. The acid may be any acid, inorganic or organic, which is effective in the generation of the diazonium salt. Preferred acids include nitric acid, HNO3, hydrochloric acid, HC1, and sulfuric acid, H2SO4. The diazonium salt may also be generated by reacting the primary amine with an aqueous solution of nitrogen dioxide. The aqueous solution of nitrogen dioxide, NO2/H2O, can provide the nitrous acid needed to generate the diazonium salt. In general, when generating a diazonium salt from a primary amine, a nitrite, and an acid, two equivalents of acid are required based on the amine. In an in situ process, the diazonium salt can be generated using one equivalent of the acid. When the primary amine contains a strong acid group, adding a separate acid may not be necessary' in some processes. The acid group or groups of the primary' amine can supply one or both of the needed equivalents of acid. When the primary amine contains a strong acid group, preferably zero to one equivalent of additional acid can be added to a process to generate the diazonium salt in situ. One example of such a primary amine that has shown exceptional properties is para-ammobenzenesulfonic acid (sulfanilic acid).

[0021] The chemically treated carbon blacks comprise a carbon black pigment having attached at least one organic group comprising an ionic or ionizable group. The chemically treated carbon black can have attached at least one organic group having the formula — X — Z, wherein X, which is a first chemical group directly attached to the carbon black, represents an ary lene group, a heteroarylene group, an aralkylene group, an alkylene group, or an alkarylene group, and Z represents a sulfonic acid group. For example, -X-Z may be a phenylsulfonic acid or a phenylsulfonic acid salt.

[0022] As indicated, the group X can represent an arylene or heteroarylene group, an alkylene group, aralkylene group, or an alkarylene group. X can be directly attached to the pigment and is further substituted with the Z group. X can be a linker group (e.g., a linking diradical) that preferably can be directly bonded between the pigment surface and the Z group. The arylene and heteroarylene groups can be an aromatic group including, but not limited to, unsaturated cyclic hydrocarbons containing one or more rings. For the heteroarylene groups, one or more ring carbons of the aromatic group are substituted by a hetero atom. The heteroatoms are non-carbon atoms such as N, S, O, or others. The hydrogens of the aromatic group can be substituted or unsubstituted. As indicated, X can represent a heteroarylene group. Where X is aralkylene or alkarylene, the aromatic group may be an arylene or a heteroarylene group.

[0023] The heteroarylene group can be a linker group which comprises, for example, at least one heterocyclic ring which contains one or more heteroatoms (e.g., one, two, three, or more heteroatoms). The heterocyclic ring can contain, for example, from 3 to 12 ring member atoms, or from 5 to 9 ring members, or 5, or 6, or 7, or 8 membered rings. The heterocyclic ring can include, for example, at least one carbon atom, or at least two carbon atoms, or other numbers of carbon atoms. When multiple heteroatoms are used in a heterocyclic ring, the heteroatoms can be the same or different. The heterocyclic group may contain a single heterocyclic ring or fused rings including at least one heterocyclic ring. The heteroarylene group can be, for example, imidazolylene, pyrazolylene, thiazolylene, isothiazolylene, oxazolylene, isoxazolylene, thienylene, furylene, fluorenylene, pyranylene, pyrrolylene, pyridylene, pyrimidylene, indolylene, isoindolylene, tetrazolylene, quinolinylene, isoquinolinylene, quinazolinylene, carbazolylene, purinylene, xanthenylene, dibenzofurylene, 2H-chromenylene, or any combinations thereof. X can also represent an arylene group, such as a phenylene, naphthylene, biphenylene phenyl, anthracenylene, and the like. When X represents an alkylene group, examples include, but are not limited to, substituted or unsubstituted alkylene groups that may be branched or unbranched. For example, the alkylene group can be, for example, a Cl -Cl 2 group such as methylene, ethylene, propylene, or butylene, or other alkylenes. In certain embodiments, the alkylene group is a C1-C3 group. When X represents aralkylene or alkarylene, the arylene and alkylene components may be any of those discussed above.

[0024] The group X can be further substituted with groups other than Z, such as one or more alkyl groups or aryl groups.

[0025] As indicated, group Z is a sulfonic acid group. The sulfonic acid group may be in the acid form or may be anionic and can be associated with a counterion of the opposite charge including counterions such as Na ⁺ , K ⁺ , Li ⁺ , NH4 ⁺ , NR'f, where R' represents hydrogen or an organic group such as a substituted or unsubstituted aryl and/or alkyl group. The sulfonic acid group can comprise a counterion that is a monovalent metal salt such as aNa ⁺ salt, a K ⁺ salt or a Li ⁺ salt. Preferably, the organic group contains an aromatic group such as a phenyl or a naphthyl group and a quaternary ammonium or a quaternary phosphonium group. The aromatic group is preferably directly attached to the carbon black. Quatemized cyclic amines, and quatemized aromatic amines, can also be used as the organic group. Thus, N-substituted pyridinium compounds, such as N-methyl- pyridyl, can be used in this regard.

[0026] The attachment (treatment) level of a sulfonic acid group on the chemically treated carbon black should be adequate to provide for a stable dispersion of the chemically treated carbon black in the solvent Attachment levels are provided in terms of moles of the sulfonic acid group per surface area (BET) of untreated carbon black. For example, ionic or ionizable groups may be attached at a level of 0.5 to 4.0 pmol/m ² , 0.7 to 3.5 pmol/m ² , or 1 to 3 pmol/nr. In some embodiments in which the organic group only includes one sulfonic acid group, the attachment level of the organic group and the sulfonic acid group will be the same. Where the organic group comprises more than one sulfonic acid group, the attachment level of the organic group and the sulfonic acid group will be different. In such cases, the levels of attachment for groups including sulfonic acid groups may also be quantified in terms of equivalents per area. These levels of attachment can be determined by methods known to those of skill in the art, such as elemental analysis.

[0027] Any polymerization method known to those of skill in the art may be employed to prepare the polyester. Suitable methods are disclosed in CN105839215, CN107326467, CN107447287, CN107624980, CN102731754, CNI0169142I, CN101338067, CN204237904U, JPS55066922A, RO79225, JPS58045227, and GB1049414, the contents of all of which are incorporated herein by reference. In a typical process, a dicarboxylic acid or its diester, e.g. in which the carboxylic acid groups are present as methyl esters, is esterified (or transesterified) with a diol. For example, the diacid may be terephthalic acid. In addition to terephthalic acid, dicarboxyhc acids such as 2,6-, 1,4-, 1,2-, or 1,5- naphthalene dicarboxylic acid, isophthalic acid, m-phtalic acid, adipic acid, glutaric acid, 1,4-cyclohexane dicarboxylic acid, p-hydroxybenzoic acid, diphenyldicarboxylic acid and diphenoxyethanedicarboxylic acid, or 4,4'-biphenyl dicarboxylic acid may also be employed, either alone or in combination with terephthalic acid or each other. More generally, the dicarboxylic acid may be one or more of an aromatic di carboxylic acid having 6 to 24 carbon atoms, a cycloaliphatic dicarboxylic acid having 6 to 24 carbon atoms, or an alkane dicarboxylic acid having 2 to 12 carbon atoms.

[0028] In certain embodiments, the diol is ethylene glycol. In general, the diol may be one or more of an alkylene diol having 2-12 carbon atoms, cycloaliphatic diol having 6- 24 carbon atoms, or aromatic diol having 6-24 carbon atoms. For example, the diol may be an alkane diol having 2-8 carbon atoms such as ethylene glycol, 1,2-propane diol, 1,3- propane diol, 1,3-butane diol, 1,4-butane diol, 1,5-pentane diol, neopentyl glycol, diethylene glycol, trimethylene glycol, tetramethylene glycol, butylene glycol, hexanemethylene glycol, 2,2,4-trimethylpentane-l,3-diol, 1,6-hexane diol or the like, cycloaliphatic diol having 6-24 carbon atoms such as 1,4-cyclohexane diol, 1,4- cyclohexane dimethanol or the like, aromatic diol having 6-24 carbon atoms such as bisphenol A, bisphenol S, hydroquinone, hydroxyphenol, xylylene glycol or the like or a mixture of two or more of these. Preferably, the diol contains less than 3 wt% water, for example, less than 2% water, less than 1% water, less than 0.5 % water, or less than 0.1 wt% water. Any water will interfere with the esterification reaction and should be minimized.

[0029] The diol-carbon black dispersion may be produced using any method known to those of skill in the art. For example, the carbon black and the diol may be combined using a media mill. The diol-carbon black dispersion preferably includes 15-25 wl% modified carbon black, for example, from 18-23 wt%, from 15-20 wt%, or from 20-25 wt%. The diol-carbon black dispersion preferably includes less than 2.5 wt% water, for example, less than 2 wt%, less than 1.5 wt%, less than 1 wt%, less than 0.5 wt%, or less than 0. 1 wt% water.

[0030] The diol-carbon black dispersion optionally includes a dispersing aid. A preferred dispersing aid is polyvinylpyrrolidone (PVP). The PVP may be present in an amount of 0 to 0.2: 1 by weight with respect to carbon black, for example, up to 0.05: 1, from 0.05: 1 to 0.1 : 1 , or from 0.1 : 1 to 0.15 : 1. The PVP may have a number average molecular weight of from 3000 g/mol to 80,000 g/mol, for example, 5000-60,000 g/mol, 6000 -50,000 g/mol, 10000-30000 g/mol, or 10,000-15,000 g/mol. Lower molecular weights, e.g. no more than 30,000 g/mol or no more than 20,000 g/mol, are preferred to promote heat stability of the carbon black dispersion. Amounts of PVP is greater than 0.2:1 with respect to carbon black may be detrimental to heat stability. The appropriate amount of PVP will vary depending on the concentration acidic groups on the carbon black

[0031] The diol-carbon black dispersion may have a low level of particle agglomeration. In preferred embodiments, D99 of the dispersion is less than 1.0 microns. More preferably, the diol-carbon black dispersion is stabile with respect to heat. For example, D99 of the dispersion may be less than 1 micron after incubation at 150 °C for two hours. [0032] During an initial esterification step, high temperatures are employed to react the diol and diacid. A metal oxide or metal acetate catalyst or other catalyst known to those of skill in the art may be employed to drive the reaction towards the desired end product. A phosphorus containing compound such as an alkyl or aryl phosphite or phosphate, or phosphorous acid, phosphoric acid, phosphonic acid, carboxyphosphonic acid or compounds of these (such as salts or esters) may be used to inactivate the esterification. Following the initial esterification, the reaction temperature is increased to promote further polycondensation, during which oligomer chains may combine via transesterification, releasing the diol as a reaction product. Any diol generated, along with residual unreacted diol, is preferably removed to discourage the back (depolymerization) reaction. The polycondensation may also be performed under vacuum to further assist the removal of the diol. An antimony-based catalyst or other suitable catalyst may also be employed during polycondensation. Following polycondensation, the polymer may further be held at high temperature and or low temperature to promote formation of high molecular weight polymer and further promote evaporation of the diol. The resulting product may have a molecular weight Mn of 17000-25000. [0033] The carbon black dispersion may be added to the reaction mixture at any stage at which diol is still being consumed in the reaction. For example, the carbon black dispersion may be added before, during, or after esterification. If esterification is conducted in two steps, for examples, at two different temperatures and/or pressures, the carbon black dispersion may be added before, during, or after either step. Likewise, the carbon black dispersion may be added prior to or at the beginning of polycondensation. [0034] In one embodiment, polymerization employing the carbon black dispersions provided herein is used to produce polyester masterbatch. The polyester masterbatch may have a carbon black loading of 15-30 wt% and may be blended with additional polyester resin and drawn or spun into fibers. Lower surface area carbon blacks may be used to achieve higher loadings but may not provide the desired tinting strength for black fiber. [0035] Alternatively, the freshly-produced polymer may be directly drawn or spun into fibers. In this embodiment, the polymer may have a lower carbon black loading, for example, 0.5-3% more typical for the fiber itself. In this embodiment, the fiber may be formed in the same process, immediately following polymerization, or the polymer may be extruded into fiber at a later time. For example, rather than being formed into fiber, the polymer may be formed into chips or other small particles that can be fed into an extruder and then drawn into fiber. In any of these embodiments, the fiber may have a jetness L* of 11-18 and either or both of a fiber tenacity of 2.0-3.5 cN/dtex and an elongation at break of 10-30%

[0036] The present invention will be further clarified by the following examples which are intended to be only exemplary in nature

EXAMPLES

Example 1

[0037] Carbon black having a BET surface area of 230 m ² /g and OAN of 69 mL/lOOg was introduced into a continuous pin pelletizer at a rate of 100 kg/hr and mixed with sulfanilic acid (10.51 kg/hr), 20% sodium nitrite solution (22.06 kg/hr) and additional water (65-75 kg/hr). The resulting surface treated carbon black was dried at 140 °C.

[0038] To make ethylene glycol dispersions, carbon black was combined with ethylene glycol and polyvinylpyrrolidone (K30, MW 40000-80000, Ashland) to make a 20% dispersion with a PVP:carbon black ratio of 0.15. 50 mL of the dispersion was charged to a half pint paint can (total material = 50 g) with 75 g of 0.8 mm zirconium beads The paint cans were shaken for six hours on a LAU DAS 200 disperser and filtered through paint screens. Particle size measurements were conducted in a Horiba L-950V2 laser scattering particle size distribution analyzer. The sample dispersions were diluted 1 :10 in isopropyl alcohol, and then 1-2 drops were added to the water-filled (about 50 mL) Miniflow chamber of the analyzer. D90 was 3.1 microns and D99 was 6.1 microns.

Example 2

[0039] Carbon black having a BET surface area of 83 m ² /g and OAN of 64 mL/lOOg was treated with para-amino benzoic acid (PABA). A plow mixer having a water cooled jacket and a chopper was charged with water and agitated until the water reached a target temperature of 60 °C. Carbon black (29% loading) and PABA (564 pmol/g) were added to the water (fill factor 67%) and the chopper started. Once the reaction mixture reached 50 °C, a 20% sodium nitrite solution was added over 20 minutes to achieve a 1: 1 molar ratio of sodium nitrite, following which the reaction was allowed to continue with both plow mixing and the chopper at a temperature of 65 °C for two hours. Sufficient water was added to the reactor to bring the fill factor to 85% and the reactor cooled to 40 °C. The slurry was discharged and diafiltered to remove residual salts and then concentrated to a solids loading of 30%.

[0040] The resulting carbon black was combined with PVP10 polyvinylpyrrolidone (MW = 10000, Aldrich) and ethylene glycol in half pint paint cans in the proportions given in Table 1 , along with 75 g of 0.8 mm zirconia beads. All formulations had 25 wt% carbon black and 50 g total material exclusive of the grinding media. The cans were agitated for four hours in a LAU DAS 200 disperser. After mixing, the dispersion was separated from the milling media with a paint fdter, and the amount of dispersion that was recovered was recorded in grams (Table 1; N/A = too viscous to fdter through paint screen). The amount of material recovered after screening (i.e., not retained on the screen) is a rough indication of dispersion viscosity. For heat stability testing, 10 g of each fdtered dispersion was heat aged in a glass vial covered with aluminum foil in an air circulating oven for two hours at 150 °C. Particle size measurements were conducted in a Horiba L- 950V2 laser scattering particle size distribution analyzer. The sample dispersions were diluted 1 :10 in isopropyl alcohol, and then 1-2 drops were added to the water-fdled (about 50 mL) Miniflow chamber of the analyzer. Rheology measurements were conducted at 25 °C. in an AR2000 rheometer from TA Instruments using a 40 mm steel parallel plate geometry. Viscosity was measured with stepped flow at shear rates from 0.1 to 1000 s ¹ and storage modulus (g’) was measured at angular frequencies between 0.1 and 500 rad/s.

[0041] Particle size distribution measurements for the dispersions before and after aging are shown in Table 2. The treated and untreated carbon black dispersions exhibit agglomeration upon aging which is not improved with the use of PVP.

Table 2

Example 3

[0042] Carbon black having a BET surface area of 117 m ² /g and an OAN of 97 cc/lOOg was treated with 1 (Example 3A) or 3 (Example 3B) pmol/m ² butyl amino benzoate. 700 g carbon black was charged into the mixing chamber of the chamber of a 4 liter ProcessAll Tilt-A-Mix plow mixer. The chamber was heated to 60 °C and butyl amino benzoate (BAB), methyl sulfonic acid (MSA), and water (Water 1) were sprayed into the mixing chamber over about 1 minute in the amounts listed in Table 3 below. The reagents were mixed for about a minute at 60 rpm, and then sodium nitrite and water (Water 2) were sprayed into the chamber in the amounts listed in Table 3 over about a minute. An air purge was set to about 10 SLPM and the reaction allowed to proceed for 80 minutes while mixing continued. The reaction mixture was allowed to cool to below 40 °C and discharged into a tray. The tray was dried in an oven set to 105 °C until the moisture content was about 2.5 wt.

Table 3

[0043] The resulting carbon black and an untreated carbon black control were each combined with PVP (MW = 10000, Aldrich) and ethylene glycol in half pint paint cans in the proportions given in Table 4, along with 75 g of 0.8 mm zirconia beads. All formulations had 25 wt% carbon black and 50 g total material exclusive of the grinding media. The cans were agitated for four hours in a LAU DAS 200 disperser. After mixing, the dispersion was separated from the milling media with a paint filter, and the amount of dispersion that was recovered was recorded in grams (Table 4; N/A = too viscous to filter through paint screen). Aging and dispersion characterization were performed as described in Example 2. The data in Table 4 show, even at 3 pmol/m ² , the treatment level was too high to make a flowable dispersion. While the particle size distribution in dispersions with both treated (1 pmol/m ² ) and untreated carbon black was heat stable (Table 5), the storage modulus of both dispersions stopped showing fluid-like variation of the storage modulus with frequency after heat treatment (Figure 1, solid square - untreated carbon black, open square - untreated carbon black dispersion after aging; closed circle - Example 3A, open circle - Example 3A dispersion after aging), indicating that heating the dispersion results in more gel-like behavior.

Table 4

Table 5

Example 4

[0044] Carbon black having a BET surface area of 117 m ² /g and an OAN of 97 cc/lOOg was treated with 3 or 6 pmol/m ² sulfanilic acid using “pellet” or "slurry" treatments described below.

[0045] In the “pellet” method, the chamber of a 4 liter ProcessAll Tilt-A-Mix plow mixer was heated to 70 °C. A 1 gallon container was used to premix 300 g carbon black and either 18.3 or 36.6 g sulfanilic acid, and the mixture was charged into the chamber of the mixer, followed by 219.9 or 186.3 g water (for 3 or 6 pmol/m ² treatment, respectively). The reaction mixture was mixed for 3 minutes at maximum speed. A 20% solution of aqueous sodium nitrite was prepared, and either 42 or 84 g of the solution (for 3 or 6 pmol/m ² treatment, respectively) was sprayed into to the reaction mixture under pressure. After five additional minutes of mixing, the treated pellets were discharged into a tray at a depth of about 2 cm. The tray was placed into a preheated oven at 110 °C and dried for about two hours until the moisture content was less than 2%.

[0046] In the “slurry” method, 300 g carbon black and either 18.3 or 36.6 g sulfanilic acid were charged into the chamber of the 4 L ProcessAll Tilt-A-Mix plow mixer having a water bath set to 55 °C. Once the bath reached a temperature over 50 °C, 450 g water was added to the mixing chamber, the plow was run at maximum speed for 30 min while the chopper function of the mixer was also engaged. At that time, either 43.8 or 87.6 g (for 3 or 6 pmol/m ² treatment, respectively) of a 20% aqueous solution of sodium nitrite was added over 10 min, after which the bath was set to 65 °C. Any remaining nitrite from the delivery apparatus was rinsed in with 50 mL deionized water. The bath was held for an additional two hours at 65 °C and the reaction mixture agitated with the plow and chopper as before for an additional two hours. At that time, 188.2 mL deionized water was fed to the reaction chamber over 15 minutes; after the first five minutes the bath was cooled to less than 50 °C by setting it to 20 °C. The reactor was discharged fifteen minutes after the last of the deionized water was fed to the reaction chamber. After discharge, the reactor was rinsed twice with two 410 mL aliquots of deionized water, following which the entire reaction mixture was diluted to a total mass of 2000 g. The dilute mixture was diafiltered to remove residual salts and achieve a solids loading of 15% and then further concentrated to 22% solids. The resulting slurry was dried in a tray in an air circulating oven at 110 °C until the moisture content was less than 2%.

[0047] Ethylene glycol dispersions with 20 wt% carbon black were prepared with polyvinylpyrrolidone (MW=10,000, Aldrich) at ratios of 0, 0.05, 0.1, and 0.2 (PVP/CB) as described in Example 1. Samples were charactenzed and aged as descnbed in Example 2. The yield after filtering the dispersions is shown in Table 6 below.

[0048] The results demonstrate that the higher (6 pmol/m ² ) level of sulfanilic acid treatment yields a less filterable dispersion. However, the yield does not vary with the concentration of PVP. Tables 7-9 show particle size data for the samples before and after aging. The results show that the sulfanilic acid treated samples are relatively stable under aging, regardless of the amount of PVP. However, the untreated carbon black dispersion shows agglomeration after aging.

Table 7

Table 8

Table 9

[0049] Figures 2 and 3 show the storage modulus G’ as a function of angular frequency for dispersions with the carbon blacks of Examples 4B and 4D before (Figure 2) and after (Figure 3) aging (Squares - no PVP; circles - PVP:CB = 0.05; triangles pointing up - PVP:CB = 0.1; triangles pointing down - PVP:CB = 0.2; solid symbols - slurry method; open symbols - pellet method). In Figure 2, the almost horizontal curves for Example 4D with no PVP shows that this dispersion exhibited gel like behavior, while the other dispersions exhibited more fluid-like behavior, with little variation with the use of PVP. However, Figure 3 shows that both dispersions of the aged dispersions (Examples 4B and 4D) treated carbon black exhibited gel-like behavior without the use of PVP. In contrast, none of the aged dispersions for Examples 4C and 4E exhibited fluid-like variation of the storage modulus with frequency, indicating that the more highly treated carbon black (6 pmol/m ² ) results in a more gel-like dispersion (Figure 4; Squares - no PVP; circles - PVP:CB = 0.05; triangles pointing up - PVP:CB = 0.1; triangles pointing down - PVP:CB = 0.2; solid symbols - slurry method; open symbols - pellet method).

[0050] Dispersions were prepared with the carbon blacks of Examples 4B and 4D but with PVP40 (Mn=40,000, Aldrich). Figure 5 shows storage modulus data for Examples 4B and 4D with two different molecular weights of PVP at a ratio of 0.1 with respect to carbon black (Solid symbols - initial dispersion; open symbols - aged dispersions; Squares - dispersion with carbon black of Example 4B and PVP40; circles - dispersion with carbon black of Example 4B and PVP 10; triangles pointing up - dispersion with carbon black of Example 4B and PVP40; triangles pointing down - dispersion with carbon black of Example 4D and PVP10). While the higher molecular weight has very little effect on aging behavior, the storage modulus of samples with the higher molecular weight PVP is consistently higher.

Example 5

[0051] Carbon black having a BET surface area of 60 m ² /g and OAN of 47 mL/lOOg was introduced into a continuous pin pelletizer at a rate of 100 kg/hr and mixed with sulfanilic acid (2.4 kg/hr) and 20% aqueous sodium nitrite (5.56 kg/hr) along with 42.1 kg/hr additional water. The resulting surface treated carbon black was then dried at 140 °C. Chips of polyethylene terephthalate (PET) having 1.5 wt% carbon black were produced with the resulting carbon black. Ethylene glycol dispersions were prepared by mixing the formulations in Table 10 below (all amounts in grams) in a 1.5 L reaction vessel at 1000 rpm using a high speed overhead mixer. The carbon black dispersion was processed through five cycles in an Eiger Mill Ml 00 VSE sand mill, (Engineered Mills, Inc.) with 1 mm diameter zirconia beads at a ratio of 1.5: 1 (beads:dispersion) at 2800 rpm, until D50 was smaller than 200 nm.

Table 10 [0052] Polyethylene terephthalate chips were prepared by combining 2594 g terephthalic acid (PT A) and 1453 g monoethylene glycol (molar ratio 1.5:1) in a 10 liter reactor. After 10 minutes of manual mixing at 20-30 °C, 225 g of one of Dispersions 5A-B and 1.5 g of ethylene glycol antimony catalyst was added. Esterification was conducted for 3 hours at 240 °C, after which the temperature was increased to 280 °C for polycondensation for two hours under vacuum (90 KPa).

[0053] The properties of the resulting PET chips are shown in Table 11 below. Intrinsic viscosity was measured using an Automatic Viscosity Meter IV400-2 from Hangzhou Zhongwang Technology Co. Ltd. according to GBT14190. Number average molecular weight (Mn) and molecular weight distribution (MWD) were measured by using a PL- GPC-50 gel permeation chromatography system from Agilent with the testing temperature set to 40 °C using hexafluoroisopropanol as the solvent. Melting point was determined using a Mettler Toledo Model DSC822e differential scanning calorimeter by heating the sample from 0 °C to 300 °C at 10 K/min and then cooling the sample back to 0 °C at the same ramp rate.

Table 11

[0054] The chips were spun in a partially orienting yam spinning machine at 3000 m/min using a 48 hole spinneret die (Zibo Linzi Fangchen Masterbatch Factory, Model FCF-1) and then processed in a draw texturing machine (Zibo Linzi Fangchen Masterbatch Factory, model FCF-10, with a drawing ratio of 1.67 to produce textured yam with a yam count of 150D/45F and having the properties listed in Table 12. Mechanical properties were performed in a temperature and humidity controlled room (25 °C/50% relative humidity) according to ASTM D2256. The fiber was knitted using a model KU483T knitting machine (Wuxi Tianxiang Knitting Machinery Co., Ltd) to make socks. Sock color (L*a*b) was measured using a Hunter UltraScan Colorimeter with the following settings: D(iffuse)/8° geometry (SCI model), 10° observer, D65 illuminant.

Table 12

[0055] The foregoing description of preferred embodiments of the present invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings, or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto, and their equivalents.

[0056] What is claimed is: