JP2018177996A - Aqueous pigment dispersion, and aqueous ink for inkjet recording containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous pigment dispersion having both of high color development and light resistance.SOLUTION: The above described problem is solved by providing an aqueous pigment dispersion containing at least a pigment, a (meth)acrylic acid ester resin, and a polycarbonate modified urethane resin including an ultraviolet absorber and a photostabilizer. Further it is solved by providing an aqueous ink for inkjet recording containing the resulting aqueous pigment dispersion.SELECTED DRAWING: None

Description

  The present invention relates to an aqueous pigment dispersion and an aqueous ink for ink jet recording containing the same.

With the widespread use of inkjet printers in recent years, the recording liquid (aqueous ink for recording) used for this is required to further improve the quality. For example, in the required quality of an inkjet printer for photo and an inkjet printer for large format, the image characteristic has priority over productivity (output speed). Above all, broad color reproducibility and image durability (light resistance, weather resistance, gas resistance) are emphasized.
In particular, in the case of a yellow pigment, there is a trade-off relationship between high color development and light resistance, and at present there is no molecular structure (CI Pigment No.) compatible with these.
Under these circumstances, attempts have been made to "control the particle size", "use of additives", etc., instead of seeking solutions for the pigment structure used. However, although all of them have a certain effect, they have not been able to satisfy the demand for high quality in recent years. In addition, if a large amount of additive is added, the possibility of adversely affecting the ejection performance and the image performance is high, which is not preferable.
Among these, for the purpose of improving light resistance etc., an ink jet ink containing water, a water-soluble organic solvent, a pigment, polycarbonate-modified urethane resin particles, an ultraviolet light absorber and a light stabilizer has been proposed (patent document 1). However, in the method described in Patent Document 1, since the ultraviolet light absorber is not distributed in the surface layer of the dots, it has not been achieved to satisfy the level of light resistance that has increased in recent years.

JP, 2016-006150, A

  The problem to be solved by the present invention is to provide an aqueous pigment dispersion having high color development and light resistance.

As a result of intensive investigations in view of such a situation, the present inventors have conceived of using a polycarbonate-modified urethane resin containing an ultraviolet absorber and a light stabilizer, and completed the present invention.
That is, the present invention relates to an aqueous pigment dispersion characterized by containing at least a pigment, a (meth) acrylic acid ester resin, and a polycarbonate-modified urethane resin containing an ultraviolet light absorber and a light stabilizer.
As a result of investigating the relationship between a urethane resin, which has been conventionally used as a component of an aqueous pigment dispersion, and a (meth) acrylic acid ester resin, the present inventors maximized the effects of the ultraviolet light absorber and the light stabilizer. It has been found that it is very effective to incorporate an ultraviolet light absorber and a light stabilizer into the polycarbonate modified urethane resin as in the above-mentioned constitution, in order to pull out.
It is estimated that the UV protection function of the internal pigment is maximized because the polyurethane layer containing the UV absorber and the light stabilizer is richly distributed on the dot surface layer by ink penetration after landing in such a configuration. Ru.

  According to the present invention, it is possible to provide an aqueous pigment dispersion having high color development and light resistance.

<Aqueous pigment dispersion (A)>
The aqueous pigment dispersion (A) of the present invention contains at least a pigment, a (meth) acrylic acid ester resin, and a polycarbonate-modified urethane resin containing an ultraviolet light absorber and a light stabilizer, and further, as required. It contains a leveling agent, an antioxidant, and other components.

<Polycarbonate modified urethane resin (B)>
The polycarbonate-modified urethane resin used for preparation of the aqueous pigment dispersion of the present invention itself has dispersibility in an aqueous medium, and is present as resin particles in the dispersion. And in this invention, it is added in the state which included the ultraviolet absorber (following: B-1) and the optical stabilizer (following: B-2) in the polycarbonate modified urethane resin particle, and it is an aqueous pigment dispersion. It can be used for the preparation of the body.
As described above, “included” means a state in which the ultraviolet light absorber (B-1) and the light stabilizer (B-2) are enclosed in resin particles. Of course, the UV absorber (B-1) and the light stabilizer (B-2) are adsorbed on the surface of the polycarbonate modified urethane resin particles in the range where the effect of the present invention is not impaired, or in the dispersion of polycarbonate modified urethane resin It does not exclude the situation where it is distributed to both.

  According to the required quality etc., you may further include an antioxidant (after-mentioned: B-3). By including the antioxidant (B-3), the oxidation of the pigment by ozone in the atmosphere can be suppressed, and the pigment can be stably present for a longer period of time.

  Here, in the present invention, the polycarbonate-modified urethane resin (B) means a polycarbonate compound (b-1) having an active hydrogen group, a compound (b-2) having at least one active hydrogen group and a hydrophilic group, and an isocyanate group Are obtained by reacting the compound (b-3) having

  As an active hydrogen group which the polycarbonate compound (b-1) which has the said active hydrogen group has, a hydroxyl group, phenolic hydroxyl group, an amino group, a mercapto group etc. are mentioned, for example. Among these, a hydroxyl group, a carboxyl group and an amino group are preferable. The polycarbonate compound (b-1) having an active hydrogen group is preferably one having two or more of these active hydrogen groups in one molecule.

  As the polycarbonate compound (b-1) having an active hydrogen group, for example, those obtained by reacting a carbonic acid ester with phosgene and a low molecular weight polyol of about 100 to 500 can be used.

  As the carbonic acid ester, methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, diphenyl carbonate and the like can be used.

  Examples of low molecular weight polyols which can react with the above-mentioned carbonates include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,7 -Heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,3 Propanediol, 2-methyl-1, 8-octanediol, 2-butyl-2-ethylpropanoldiol, 2-methyl-1, 8-octanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, Relatively low molecular weight dihydroxy compounds such as hydroquinone, resorcine, bisphenol A, bisphenol F, 4,4'-biphenol, polyether polyols such as polyethylene glycol, polypropylene glycol, polyoxy tetramethylene glycol, polyhexamethylene adipate, Polyester polyols such as polyhexamethylene succinate, polycaprolactone and the like can be used.

  It is preferable to use what has a number average molecular weight of 500-3,000 as a polycarbonate compound (b-1) which has the said active hydrogen group. Among them, the number of 1,500 to 2,500 is more preferable, in the case where excellent bending resistance is compatible with good heat resistance, hydrolysis resistance and durability such as sweat resistance and oil resistance. Polycarbonate polyols having an average molecular weight can be used. In addition, the weight average molecular weight of the polycarbonate compound (b-1) which has the said active hydrogen group shows the value obtained by measuring on condition of the following by gel permeation column chromatography (GPC) method.

Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were used in series connection.
"TSKgel G5000" (7.8 mm ID × 30 cm) × 1 "TSK gel G 4000" (7.8 mm ID × 30 cm) × 1 "TSK gel G 3000" (7.8 mm ID × 30 cm) × 1 This "TSKgel G2000" (7.8 mm ID × 30 cm) × 1 detector: RI (differential refractometer)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

(Standard polystyrene)
Tosoh Corporation "TSKgel standard polystyrene A-500"
Tosoh Corporation "TSKgel standard polystyrene A-1000"
Tosoh Corporation "TSKgel standard polystyrene A-2500"
Tosoh Corporation "TSKgel standard polystyrene A-5000"
Tosoh Corporation "TSKgel standard polystyrene F-1"
Tosoh Corporation "TSKgel standard polystyrene F-2"
Tosoh Corporation "TSKgel standard polystyrene F-4"
Tosoh Corporation "TSKgel standard polystyrene F-10"
Tosoh Corporation "TSKgel standard polystyrene F-20"
Tosoh Corporation "TSKgel standard polystyrene F-40"
Tosoh Corporation "TSKgel standard polystyrene F-80"
Tosoh Corporation "TSKgel standard polystyrene F-128"
Tosoh Corporation "TSKgel standard polystyrene F-288"
Tosoh Corporation "TSKgel standard polystyrene F-550"

  As the polycarbonate compound (b-1) having an active hydrogen group, for example, polyether polyol, polyester polyol, other polycarbonate polyol, dimer diol, acrylic polyol, polybutadiene polyol and the like can be used. These polyols may be used alone or in combination of two or more.

  The compound (b-2) having at least one active hydrogen group and a hydrophilic group is a compound having at least one active hydrogen group and a hydrophilic group, but has at least one active hydrogen group as described above, Examples of the hydrophilic group include compounds having a carboxyl group, a sulfonic acid group and a salt thereof, and a compound having a nonionic hydrophilic group having a repeating unit of an alkylene oxide and the like. The compound (b-2) having the at least one active hydrogen group and the hydrophilic group may be used alone or in combination of two or more.

  Examples of the compound (b-2) having at least one active hydrogen group and a hydrophilic group include, for example, 2,2-dimethylol propionic acid, 2,2-dimethylol butyric acid, 2,2-dimethylol valeric acid, and dioxy Maleic acid, 2,6-dioxybenzoic acid, 3,4-diaminobenzoic acid, succinic acid, adipic acid, maleic acid, phthalic acid, alanine, aminobutyric acid, aminocaproic acid, glycine, glutamic acid, aspartic acid, carboxyls such as histidine Examples thereof include compounds having a group and a hydroxyl group or an amino group, or dicarboxylic acid compounds.

  Moreover, as a compound which has a sulfonic acid group as said hydrophilic group, 2-oxyethane sulfonic acid, phenol sulfonic acid, sulfobenzoic acid, sulfosuccinic acid, 5-sulfo isophthalic acid, sulfanilic acid, 1,3- Compounds having a sulfonic acid group such as phenylenediamine-4,6-disulfonic acid, 2,4-diaminotoluene-5-sulfonic acid and the like, and a hydroxyl group, a carboxyl group or an amino group, or a disulfonic acid compound can be mentioned.

  Furthermore, as the compound having a nonionic hydrophilic group as the hydrophilic group, for example, polyethylene glycol, polypropylene glycol, a copolymer of ethylene oxide and propylene oxide, a copolymer of ethylene oxide and polybutylene oxide, ethylene Copolymers of oxides and other alkylene oxides may, for example, be mentioned.

  The compound (b-2) having at least one active hydrogen group and a hydrophilic group is 0.5% by mass to 10% by mass with respect to the total amount of the polycarbonate compound (b-1) having the active hydrogen group. It is preferable to use in the range, and it is more preferable to use in the range of 1% by mass to 5% by mass.

Examples of the compound (b-3) having an isocyanate group include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2-diphenylmethane diisocyanate, 3,3-dimethyl-4,4-biphenylene diisocyanate, 3,3-dimethoxy-4,4'-biphenylene diisocyanate, 3,3'-dichloro-4,4 4-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, tetramethylene diisocyanate, 1,6-hexanemethylene diisocyanate, dodecamethylene diisocyanate Sociate, trimethylhexamethylene diisocyanate, 1,3-cyclophexylene diisocyanate, 1,4-cyclophexylene diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,4 And polyisocyanates such as -dicyclo phenoxy methane diisocyanate and 3, 3-dimethyl-4, 4- dicyclo phenoxy methane diisocyanate. These isocyanate group-containing compounds may be used alone or in combination of two or more.

  Further, among the compounds (b-3) having an isocyanate group, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, and 4,4-dicyclophenyl methane diisocyanate are preferable in that they can improve light resistance and heat resistance. .

  As a method for producing the polycarbonate-modified urethane resin (B), for example, the polycarbonate compound (b-1) having the active hydrogen group in the absence of a solvent or in the presence of an organic solvent, and the compound (b-) having the isocyanate group 3) to produce a urethane prepolymer having an isocyanate group, and then reacting the urethane prepolymer with the compound (b-2) having the at least one active hydrogen group and a hydrophilic group Of producing a polycarbonate compound (b-1) having the active hydrogen group, a compound (b-3) having the isocyanate group, and a compound (b-) having the at least one active hydrogen group and a hydrophilic group 2) in one batch, and react for approximately 3 hours to 10 hours at 50 ° C. to 100 ° C. Then, a urethane prepolymer having an isocyanate group is obtained, and the polycarbonate-modified urethane resin is dispersed in the water by supplying water described later and an emulsifier if necessary, mixing and stirring, and then the urethane The method of mixing and reacting a prepolymer and the compound (b-2) which has a carboxyl group as said hydrophilic group is mentioned. In addition, when mixing the said urethane prepolymer and the said water, you may use machines, such as a homogenizer, as needed. When the liquid mixture of the urethane prepolymer and the water and the compound (b-2) having a carboxyl group as a hydrophilic group contains an organic solvent solution, it is preferable to remove the solvent thereafter.

  Examples of the organic solvent include ketone solvents such as acetone and methyl ethyl ketone; ether solvents such as tetrahydrofuran and dioxane; acetic acid ester solvents such as ethyl acetate and butyl acetate; nitrile solvents such as acetonitrile; dimethylformamide, N-methylpyrrolidone and the like An amide solvent can be used. These organic solvents may be used alone or in combination of two or more.

  The reaction between the polycarbonate compound (b-1) having the active hydrogen group, the compound (b-3) having the isocyanate group, and the compound (b-2) having a carboxyl group as the hydrophilic group is the reaction of the active hydrogen group. The compound (b-) having the isocyanate group and the sum of the hydroxyl group of the polycarbonate compound (b-1) having a hydroxyl group and the hydroxyl group and / or amino group of the compound (b-2) having a carboxyl group as the hydrophilic group The equivalent ratio [isocyanate group / (hydroxyl group + amino group)] with the isocyanate group possessed by 3) is preferably in the range of 0.5 to 1.5, and in the range of 0.9 to 1.1. More preferable.

  The mass ratio of the polycarbonate-modified urethane resin (B) to the aqueous medium is preferably in the range of 10/80 to 70/30 from the viewpoint that the workability and the texture of the film can be further improved, and 20/80. The range of -60/40 is more preferable.

  The aqueous polycarbonate-modified urethane resin (B) of the present invention contains the polycarbonate-modified urethane resin (B) and the aqueous medium as essential components, but as necessary, a chain extender (b-4), an emulsifier ( b-5), a neutralizing agent (b-6) and other additives may be contained.

  The desired polycarbonate-modified urethane resin (isocyanate group-containing urethane prepolymer or an organic solvent solution thereof, or an aqueous dispersion thereof) is prepared by mixing polyalkanolamine (b-7) and reacting at a normal temperature of 25 ° C. B) can be manufactured. At that time, the amount of hydroxyl groups introduced into the obtained polycarbonate-modified urethane resin (B) can be adjusted by adjusting the amount of use of the polyalkanolamine.

  As said chain extender (b-4), a polyamine, a hydroxyl-containing compound, etc. can be used, for example.

  Examples of the polyamine include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophorone diamine, 4,4'-dicyclohexylmethanediamine, 3,3'- Diamines such as dimethyl-4,4'-dicyclohexylmethanediamine and 1,4-cyclohexanediamine; N-hydroxymethylaminoethylamine, N-hydroxyethylaminoethylamine, N-hydroxypropylaminopropylamine, N-ethylaminoethylamine, Diamines containing one primary amino group and one secondary amino group such as N-methylaminopropylamine; Polyamines such as diethylenetriamine, dipropylenetriamine and triethylenetetramine; Hydrazine, N Hydrazines such as N'-dimethylhydrazine, 1,6-hexamethylenebishydrazine; succinic acid dihydrazide, adipic acid dihydrazide, glutaric acid dihydrazide, sebacic acid dihydrazide, diphthalic acid dihydrazides such as isophthalic acid dihydrazide; β-semicarbazide propionic acid hydrazide, Semicarbazides such as 3-semicarbazide-propyl-carbazic acid ester, semicarbazide-3-semicarbazide methyl-3,5,5-trimethylcyclohexane can be used.

  Examples of the hydroxyl group-containing compound include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, sucrose and methylene. Glycols such as glycol, glycerin and sorbitol; bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, hydrogenated bisphenol A, phenols such as hydroquinone, Water and the like can be used singly or in combination of two or more, within the range where the storage stability of the urethane resin composition used in the present invention is not reduced.

  The chain extender (b-4) introduces a urea bond, and as a result, from the viewpoint of further improving the durability, relative to the total amount of raw materials used for producing the polycarbonate-modified urethane resin (B) It is preferable to use in the range of 1% by mass to 10% by mass, and more preferably in the range of 1% by mass to 5% by mass.

  The emulsifier (b-5) is, for example, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene styryl phenyl ether, polyoxyethylene sorbitol tetraoleate, polyoxyethylene / polyoxypropylene copolymer, etc. Nonionic emulsifiers; fatty acid salts such as sodium oleate, alkyl sulfates, alkyl benzene sulfonates, alkyl sulfosuccinates, naphthalene sulfonates, polyoxyethylene alkyl sulfates, alkane sulfonate sodium salts, alkyl diphenyl ether sulfonates Anionic emulsifiers such as acid sodium salts; Cationic emulsifiers such as alkylamine salts, alkyltrimethylammonium salts, alkyldimethylbenzylammonium salts Etc. can be used. These emulsifiers may be used alone or in combination of two or more.

  The neutralizing agent (b-6) neutralizes the carboxyl group in the polycarbonate-modified urethane resin (B), and examples thereof include nonvolatile bases such as sodium hydroxide and potassium hydroxide; trimethylamine, triethylamine, Tertiary amine compounds such as dimethylethanolamine, methyldiethanolamine, triethanol and the like can be used. These neutralizing agents may be used alone or in combination of two or more.

  The amount of the neutralizing agent (b-6) used is such that the molar ratio in the range of 0.8 to 1.2 is with respect to the number of moles of the carboxyl group contained in the polycarbonate modified urethane resin (B). It is preferable to add.

  Examples of the polyalkanolamines (b-7) include diethanolamine, 2-amino-1,3-propanediol, (R) -3-amino-1,2-propanediol, tris (hydroxymethyl) aminoethane, and the like. -An amine having a plurality of hydroxyl groups per amino group such as amino-1-deoxy-D-glucitol is used alone within the range in which the storage stability of the urethane resin composition used in the present invention is not reduced. Or in combination of two or more.

  The proportion of the pigment and the non-volatile component of the polycarbonate-modified urethane resin (B) in the aqueous pigment dispersion is not particularly limited, but 100 parts of pigment in mass conversion of non-volatile component of the polycarbonate-modified urethane resin (B) Can be selected from the range of 10 to 100 parts. As the aqueous ink for inkjet recording, the viscosity of the aqueous pigment dispersion is desired to be as low as possible for maintaining the ejection characteristics, so the polycarbonate-modified urethane resin (B) is 10 per 100 parts of pigment in mass conversion of non-volatile matter. It is more preferable to use 80 parts.

<UV absorber>
There is no restriction | limiting in particular as an ultraviolet absorber, Although it can select suitably according to the objective, For example, a benzophenone series ultraviolet absorber, a benzotriazole type ultraviolet absorber, a salicylate type ultraviolet absorber, a cyanoacrylate type ultraviolet absorber, Nickel complex salt type ultraviolet absorbers, oxalic acid anilide type ultraviolet absorbers, triazine type ultraviolet absorbers, etc. may be mentioned. As described above, in the present invention, excellent light resistance was successfully obtained by using one in which the UV absorber and the below-described light stabilizer are included in the polycarbonate modified urethane resin.

  Specifically, 2- (2H-benzotriazol-2-yl) -p-cresol, 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) Phenol, 2- [5-chloro (2H) -benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol, 2- (2-hydroxy-5-t-butylphenyl) -2H- Benzotriazole, 2- (2H-benzotriazol-2-yl) -4,6-di-tert-pentylphenol, 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3 -Tetramethylbutyl) phenol, 2,2'-methylenebis [6- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol], methyl Reaction product of -3- [3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl] propionate / polyethylene glycol 300, 2- (2H-benzotriazol-2-yl) -6-dodecyl-4-methylphenol, 2,2-bis {[2-cyano-3,3-diphenylacryloyl-oxy] methyl} propane-1,3-diyl = bis (2-cyano-3,3-) Diphenyl acrylate), ethyl 2-cyano-3,3-diphenylacrylate, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, 2- (4,6-diphenyl-1,3,5-triazine) -2-yl) -5-[(hexyl) oxy] phenol and the like.

<Light stabilizer>
There is no restriction | limiting in particular as a light stabilizer, Although it can select suitably according to the objective, For example, a hindered amine light stabilizer etc. can be used. As described above, in the present invention, the use of one containing these light stabilizers together with the ultraviolet absorber in a polycarbonate-modified urethane resin has succeeded in obtaining excellent light resistance.

  Specifically, dibutylamine-1,3,5-triazine-N, N'-bis (2,2,6,6-tetramethyl-4-piperazyl-1,6-hexamethylenediamine / N- (2 2,2,6,6-Tetramethyl-4-piperidyl) butylamine polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4 -Diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}], dimethyl succinate / Polycondensate of 4-hydroxy-2,2,6,6-tetramethyl-1-piperidine ethanol, 1,2,3,4-butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4 Piperidinol and 3,9-bis (2- Mixed esterified product with droxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, bis (1,2,2,2,6,6-pentamethyl-4-) Piperidyl) [{3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl} methyl] butyl malonate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate / methyl -1,2,2,6,6-pentamethyl-4-piperidyl sebacate, poly- (N-β-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidyl succinate), bis ( 2,2,6,6-Tetramethyl-4-piperidyl) sebacate, N, N'-bis (2,2,6,6-tetramethyl-4-piperidyl) -N, N'-diformylhexamethyle Diamine and the like.

<Antioxidant>
There is no restriction | limiting in particular as an antioxidant, Although it can select suitably according to the objective, For example, a hindered phenol type, phosphorus type, sulfur type antioxidant etc. can be used. As described above, in the present invention, by using the antioxidant and the UV absorber / light stabilizer incorporated in the polycarbonate modified urethane resin, it succeeded in obtaining excellent light resistance. .

  Specifically, penerythritol tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, thiodiethylene bis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate, Octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N'-hexane-1,6-diylbis [3- (3,5-di-tert-butyl) -4-hydroxyphenylpropion) amide], benzenepropanoic acid, 3,5-bis (1,1-dimethyl-ethyl) -4-hydroxy-C7-C9 side chain alkyl ester, 3,3 ′, 3 ′ ′, 5,5 ′, 5 ′ ′-hexa-tert-butyl-a, a ′ ′, (a) ′ ′-(mesitylene-2,4,6-triyl) tri-p-cresol, A: Lucium diethylbis {[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl} phosphonate / polyethylene wax, 4,6-bis (octylthiomethyl) -o-cresol, ethylene bis (oxy) Ethylene) bis [3- (5-tert-butyl-4-4-hydroxy-m-tolyl) propionate], hexamethylene-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate ], 2,6-di-tert-butyl-4- (4,6-bis (octylthio) 1,3,5-triazin-2-ylamino) phenol, tris (2,4-di-tert-butylphenyl) Phosphite / pentaerythritol tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate, ethylenebis (oxyethylene) bis [3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate], N, N'-hexane-1,6-diylbis (3- (3,5- (3- (3,5-) Di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 -(1H, 3H, 5H) -trione, a reaction product with N-phenylbenzenamine / 2,4,4-trimethylpentene, 2,6-di-tert-butyl-4-[(4,6-bis ( Octylthio) -1,3,5-triazin-2-ylamino) phenol, 3,9-bis (2- (3- (3-tert-butyl-4-hydroxy-5-methylphenyl) -propane) Lopionyloxy) -1,1-dimethylethyl) -2,4,8,10-tetraoxo-spiro (5,5) undecene, triphenyl phosphite, tris (2,4-di-tert-butylphenyl) phosphite, bis [2,4-bis (1,1-dimethylethyl) -6-methylphenyl] ethyl ester phosphorous acid, 2 ′, 3-bis [3- [3,5-di-tert-butyl-4-hydroxyphenyl ] Propiono hydrazide], didodecyl-3,3'-thiodipropionate, dioctadecyl-3,3'-thiodipropionate and the like.

  Moreover, in order to improve light resistance and heat resistance, it is effective to combine the above-mentioned ultraviolet light absorber with a light stabilizer or an antioxidant alone or in combination. In addition, the addition amounts of the ultraviolet absorber, the light stabilizer, and the antioxidant include the polycarbonate compound (b-1) having the active hydrogen group constituting the polycarbonate-modified urethane resin, and a carboxyl group as the hydrophilic group. It is effective to add 0.01 to 4.0 parts by weight each of the ultraviolet absorber, the light stabilizer and the antioxidant to the total 100 parts by weight of the compound (b-2) having the It is more preferable to add .0 parts by weight.

  Furthermore, in the aqueous pigment dispersion, the ratio of the pigment to the above-mentioned UV absorber, light stabilizer, and antioxidant is 100 parts of pigment, and the UV absorber, light stabilizer, and antioxidant each have a ratio of 0. It is preferable to add in the range which becomes 05 mass% or more and 0.7 mass% or less, and it is more preferable that it is 0.1 mass% or more and 0.5 mass% or less. Sufficient light resistance can be obtained by making each of the ultraviolet absorber, the light stabilizer, and the antioxidant 0.05% by mass or more, and by using 0.7% by mass or less, the aqueous ink for inkjet recording can be used without any problem. it can. Moreover, if it is in the above-mentioned more preferable range, more excellent light resistance can be obtained, and the discharge characteristic can be further improved.

<Pigment>
The pigment used for the preparation of the aqueous pigment dispersion of the present invention is an organic pigment or an inorganic pigment, and any of known ones can be used. For example, azo, disazo, azomethine, anthraquinone, quinophthalone, quinacridone, diketopyrrolopyrrole, dioxazine, benzimidazolone, phthalocyanine, isoindoline, isoindolinone, perylene, etc. Organic pigments and inorganic pigments such as carbon black.

<(Meth) acrylic ester resin>
The (meth) acrylic ester resin used for the preparation of the aqueous pigment dispersion of the present invention is one obtained by polymerizing acrylic ester or methacrylic ester as an essential component. In the present invention, both acrylic ester and methacrylic ester are included to be referred to as (meth) acrylic ester. In the present invention, in order to stably disperse the (meth) acrylic ester resin in the aqueous medium, it is preferable to include an anionic group in the structure thereof.
As such an anionic group-containing (meth) acrylic acid ester resin, for example, one or more of an ethylenically unsaturated monomer containing an anionic group such as a carboxyl group, a sulfonic acid group, a phosphoric acid group or a thiocarboxyl group And copolymer resins obtained by copolymerizing (meth) acrylic acid esters and other ethylenically unsaturated monomers copolymerizable with them as required.
In view of the availability of raw material monomers, the cost, etc., a copolymer resin containing a carboxyl group or a sulfone group is preferable, and the carboxyl group can be widely controlled in that the coexistence range of the electrical neutral state and the anionic state can be widely controlled. The (meth) acrylic ester resin contained is more preferable. The preferred (meth) acrylic ester resins are (meth) acrylic ester resins in which the anionic group contains both a carboxyl group and a salt of a carboxyl group.
Examples of the ethylenically unsaturated monomer containing a carboxyl group include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, 4-vinylbenzoic acid and the like; vinyl succinate And polybasic acid unsaturated esters such as allyl maleate, vinyl terephthalate and allyl trimetitate. Further, examples of the monomer containing a sulfonic acid group include unsaturated carboxylic acid sulfo-substituted alkyl or aryl esters such as 2-sulfoethyl acrylate and 4-sulfophenyl methacrylate: sulfocarboxylic acid unsaturated esters such as vinyl sulfosuccinate And sulfostyrenes such as styrene-4-sulfonic acid.
Examples of (meth) acrylic acid esters include methyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, (meth) acrylate Examples include dodecyl, octadecyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, and benzyl (meth) acrylate.
As another ethylenically unsaturated monomer which can be copolymerized, for example, unsaturated such as dimethyl maleate, dimethyl fumarate, 2-hydroxyethyl (meth) acrylate, 2-aminoethyl (meth) acrylate, etc. Fatty acid esters; unsaturated fatty acid amides such as (meth) acrylamide, N-methyl (meth) acrylamide; unsaturated nitriles such as (meth) acrylonitrile; unsaturated ethers such as vinyl acetate and vinyl propionate; styrene α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-t-butylstyrene, 4-methoxystyrene, 4-chlorostyrene, isostyrenes; ethylene, propylene, 1-butene, 1 -Unsaturated hydrocarbons such as octene, vinylcyclohexane, 4-vinylcyclohexene, etc. Unsaturated halogenated hydrocarbons such as vinyl chloride, vinylidene chloride, tetrafluoroethylene, 3-chloropropylene and the like; vinyl substituted heterocyclic compounds such as 4-vinylpyridine, N-vinylcarbazole, N-vinylpyrrolidone and the like; Reaction product of a monomer having a substituent having a carboxyl group, a hydroxyl group, an amino group, etc. in the above exemplified monomers and a substituent having an active hydrogen and ethylene oxide, propylene oxide, cyclohexene oxide, etc., epoxides; Examples include reaction products of monomers containing substituents having hydroxyl groups and amino groups in the body with carboxylic acids such as acetic acid, propionic acid, butanoic acid, hexanoic acid, decanoic acid and dodecanoic acid. .
As the (meth) acrylic ester resin, styrene (meth) containing styrene as a polymerization unit in that higher effects can be obtained in the concentration and the abrasion resistance of the colored image by the combined use with the polyurethane resin It is preferred to select an acrylic ester copolymer resin.
In the present invention, the carboxyl group-containing (meth) acrylic acid ester resin may or may not have a crosslinking portion, for example. The resin having a crosslinking portion is copolymerized with a monomer as described above in combination with a glycidyl group-containing ethylenically unsaturated monomer such as 2,3-epoxypropyl (meth) acrylate. After forming a resin having crosslinkability, it can be obtained by crosslinking in combination with a curing accelerator as necessary in any step of producing an aqueous pigment dispersion.
The weight average molecular weight of the (meth) acrylic ester resin used in the present invention is that the viscosity of the dispersion is low, the dispersion stability is also good, and stable printing can be performed for a long time when applied to an ink for inkjet recording. Is preferably in the range of 2,000 to 100,000, and particularly preferably in the range of 5,000 to 50,000.
In addition, the acid value and glass transition point of the (meth) acrylic ester resin used in the present invention are in the range of 30 to 220 mg KOH / g and -20 to 100 ° C., particularly 80 to 220 mg KOH / g and 0 to 90 ° C. However, the dispersibility and dispersion stability of the dispersion are good, and the printing stability when applied to an ink jet recording ink is good, and the water resistance of the image is also good. As the (meth) acrylic ester resin, It is preferable to select a styrene- (meth) acrylic acid ester copolymer resin containing styrene as a polymerization unit in that higher effects are obtained in the density of the colored image and the abrasion resistance by the combined use with the polyurethane resin. preferable.
In the present invention, the carboxyl group-containing (meth) acrylic acid ester resin may or may not have a crosslinking portion, for example. The resin having a crosslinking portion is copolymerized with a monomer as described above in combination with a glycidyl group-containing ethylenically unsaturated monomer such as 2,3-epoxypropyl (meth) acrylate. After forming a resin having crosslinkability, it can be obtained by crosslinking in combination with a curing accelerator as necessary in any step of producing an aqueous pigment dispersion.
The weight average molecular weight of the (meth) acrylic ester resin used in the present invention is that the viscosity of the dispersion is low, the dispersion stability is also good, and stable printing can be performed for a long time when applied to an ink for inkjet recording. It is preferably in the range of 2,000 to 100,000, and particularly preferably in the range of 5,000 to 50,000, in view of easiness of
In addition, the acid value and glass transition point of the (meth) acrylic ester resin used in the present invention are in the range of 30 to 220 mg KOH / g and -20 to 100 ° C., particularly 80 to 220 mg KOH / g and 0 to 90 ° C. However, the dispersibility and the dispersion stability of the dispersion are good, and the printing stability when applied to an ink jet recording ink is good, the water resistance of the image is also good, and the abrasion resistance and the stacking resistance are also good. And the like, which is preferable because the image storability such as is also good.
The (meth) acrylic acid ester resin in the aqueous pigment dispersion of the present invention is in the form in which at least a part of the anionic group is ionized by the basic substance, in addition to the expression of dispersibility and dispersion stability. Preferred. It is preferable that the optimum ratio of ionized groups among the anionic groups is usually set in the range of 30 to 100%, particularly 40 to 60%. The proportion of ionized groups does not mean the molar ratio of anionic groups to basic substances, but takes into account the dissociation equilibrium. For example, in the case where the anionic group is a carboxyl group, the proportion of a group (carboxylate group) ionized by dissociation equilibrium is less than 100% even if a stoichiometrically equivalent strong basic substance is used, and the carboxylate group is And a carboxyl group are mixed.
As such, as the (meth) acrylic acid ester resin and the neutralizing agent (basic substance) used to ionize at least a part of the anionic group, publicly known and commonly used substances can be mentioned.

  The proportion of the pigment and the (meth) acrylic ester resin non-volatile component in the aqueous pigment dispersion is not particularly limited, but 100 parts of the pigment in mass conversion of the (meth) acrylic ester resin non-volatile component However, it can be selected from the range of 10 to 50 parts. In order to achieve both the storage stability of the aqueous pigment dispersion and the discharge characteristics, the range of 15 to 40 parts is more preferable.

In the aqueous pigment dispersion of the present invention, the dispersed particles contained therein may be particles in which the pigment particles, the (meth) acrylic ester resin particles and the polyurethane resin particles are independent of one another, but the pigment is It is preferable that it is a mixture of composite particles which are particles coated with (meth) acrylic acid ester resin and polyurethane resin particles. When the pigment is a mixture of composite particles, which are particles coated with the (meth) acrylic ester resin, and polyurethane resin particles, the effects of pigment dispersibility and scratch resistance can be fully exhibited. It is preferable in point.
In the aqueous pigment dispersion of the present invention, the particles dispersed in the aqueous medium (dispersed particles) are preferably dispersed in the aqueous medium such that the average dispersed particle size is 50 to 200 nm.
In the present invention, when the polyurethane resin is not chemically bonded to (meth) acrylic acid ester resin in (meth) acrylic acid ester resin particles or composite particles, the abrasion resistance of the colored film becomes better. preferable.
The (meth) acrylic ester resin particles used in the present invention or the aqueous pigment dispersion containing the composite particles can be produced, for example, by the following methods 1) to 4).
1) A method of producing an aqueous pigment dispersion in which a pigment is mechanically forcedly dispersed in the aqueous dispersion of the (meth) acrylic acid ester resin.
2) A method of producing an aqueous pigment dispersion, in which the above-mentioned monomers are polymerized in water in the presence of a pigment using a dispersant and associated as required.
3) The mixture of the pigment, the (meth) acrylate resin and the organic solvent is gradually phase-inverted from the oil phase to the water phase using water and a basic substance, and then the solvent is desolvated, and the pigment is 2.) A method for producing an aqueous pigment dispersion containing the composite particles, which is a microcapsule type composite particle coated with an acrylic ester resin.
4) A solvent is removed from a homogeneous mixture of a pigment, the above (meth) acrylic acid ester resin, a basic substance, an organic solvent and water, an acid is added to acidify the precipitate, and the precipitate is washed. A method for producing an aqueous pigment dispersion comprising the composite particles, wherein the pigment is dispersed in an aqueous medium together with the substance, wherein the pigment is a microcapsule type composite particle coated with the (meth) acrylic acid ester resin.
In the method for producing an aqueous pigment dispersion according to the present invention, the step of dispersing a mixture comprising a pigment, a (meth) acrylate resin, a basic substance and water is essential as a matter of whichever of the above-mentioned production methods. Is preferred. Preferably, the mixture comprises a water soluble organic solvent. More specifically, it is preferable to include a step (dispersion step) of dispersing a mixture of at least a pigment, a (meth) acrylic acid ester resin, a basic substance, a water-soluble organic solvent and water.
In addition, a water-soluble organic solvent can be used in combination in the dispersing step, whereby the liquid viscosity in the dispersing step may be reduced. Examples of water-soluble organic solvents include ketones such as acetone, methyl ethyl ketone, methyl butyl ketone and methyl isobutyl ketone; methanol, ethanol, 2-propanol, 2-methyl-1-propanol, 1-butanol, 2-methoxyethanol Etc .; Ethers such as tetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane etc .; Amides such as dimethylformamide, N-methylpyrrolidone etc., and in particular, having 3 to 6 carbon atoms It is preferable to use a compound selected from the group consisting of ketones and alcohols having 1 to 5 carbon atoms. These water-soluble organic solvents may be used as a (meth) acrylic acid ester resin solution, or may be separately and independently added to the dispersion mixture.
As a dispersing apparatus which can be used in the dispersing step, apparatuses according to various known methods can be used and are not particularly limited. For example, it is made of steel, stainless steel, zirconia, alumina, silicon nitride, glass or the like Method using kinetic energy of spherical dispersion medium with diameter of about 0.1 to 10 mm, method using shear force by mechanical stirring, pressure change of flow distribution flux bundle supplied at high speed, change of flow path or collision It is possible to adopt a distributed system such as a system using the force generated by
In the aqueous pigment dispersion of the present invention, the pigment is coated with the (meth) acrylic acid ester resin in order to exhibit more excellent properties in all aspects of dispersion reaching level, dispersion required time and dispersion stability. It is preferable to be dispersed in an aqueous medium in the form of particles (that is, microcapsule type composite particles described above).
In order to form such a state, in the state in which the pigment is dispersed in the liquid medium containing the (meth) acrylic acid ester resin, (meth) acrylic which is in a dissolved state as a step after the dispersing step. It is preferred to incorporate the step of coating the pigment surface with an acid ester resin. In the step of coating the pigment surface with the (meth) acrylic ester resin in a dissolved state, the (meth) acrylic ester resin dissolved in an aqueous solution of a basic substance is deposited by acidifying the solution The step of acidification (acid precipitation step) is preferred.
Examples of the distillation step include a step of removing the organic solvent when it is used in the dispersion step, and a step of removing excess water to obtain a desired solid concentration.
In the example of the acid separation step, the aqueous dispersion obtained in the dispersion step is acidified by adding an acid such as hydrochloric acid, sulfuric acid or acetic acid to form a salt with a base, and the (meth) acrylic acid ester is in a dissolved state. There is a step of precipitating the resin on the surface of the pigment particle and the like. This step can enhance the interaction between the pigment and the (meth) acrylic ester resin. As a result, it is possible to take a form in which the microcapsule type composite particles as described above are dispersed in an aqueous dispersion medium, and as an aqueous dispersion, physical properties such as dispersion reaching level and dispersion stability and solvent resistance In the aspect of use aptitude, etc., more excellent characteristics can be exhibited.
Examples of the filtration step include a step of filtering the solid content after the above-mentioned acid precipitation step with a filter press, a Nutsche type filter device, a pressure filtration device or the like. An example of the redispersion step is a step of adding a basic substance and, if necessary, water and additives to the solid content obtained by the acid separation step and the filtration step, to form a dispersion again. Thereby, it is possible to change the counter ion of the ionized anionic group in the (meth) acrylate resin from the one used in the dispersion step.
In the present invention, it is described above that it is preferable that the (meth) acrylic ester resin and the above-mentioned polyurethane resin are not chemically bonded, but it is more preferable that both are not physically in close contact with each other. . In that sense, the step of dissolving the (meth) acrylic acid ester resin is carried out in the absence of a polyurethane resin, and the polyurethane resin and the pigment containing an anionic group-containing (meth) acrylic acid ester after the above-mentioned acid precipitation step. The method of adding to the aqueous pigment dispersion containing composite particles which are resin-coated particles is optimum.
A mixture of pigment particles and particles of anionic group-containing (meth) acrylate resin, or an aqueous pigment dispersion containing composite particles in which the pigment is a particle coated with an anionic group-containing (meth) acrylate resin The aqueous pigment dispersion of the present invention can be obtained by adding the polyurethane resin and uniformly stirring and mixing. In order to achieve uniform stirring, apparatuses according to the various methods already known and described above can be used.

  Examples of the water-soluble organic solvent used for the preparation of the aqueous ink for ink jet recording include alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol and glycerin, or alkyl ethers of the alcohols, aryl ethers, It is possible to use esters or water-soluble aprotic organic solvents such as dimethylformamide (DMF), dimethyl sulfoxide (DMSO), pyrrolidone, 2-methylpyrrolidone and the like. The selection of the organic solvent to be used in the aqueous pigment recording liquid is carried out according to the head system, and the addition amount is also limited, so that it is possible to use the organic resin of the polyurethane resin. It is desirable to use as a dispersion medium.

<Water>
In the present invention, examples of the "water" include pure water or ultrapure water such as ion exchange water, ultrafiltered water, reverse osmosis water, and distilled water.

  The aqueous pigment dispersion of the present invention thus obtained can obtain a colored film having a high coloring density and excellent scratch resistance on a recording medium, for example, in various coloring applications such as aqueous inks and aqueous paints. Of course, significantly better light fastness is obtained.

The aqueous pigment dispersion of the present invention is prepared as an aqueous pigment recording liquid so as to have a dispersed particle content of 1 to 8% by mass conversion. In this case, water or a water-soluble organic solvent may be added as necessary to the above-mentioned more concentrated aqueous pigment dispersion to dilute it to a necessary dispersed particle content, a wetting agent, an antifungal agent, etc. The various additives necessary for the preparation of aqueous inks can be used in combination. Further, the obtained aqueous pigment recording liquid can be made into an aqueous pigment recording liquid with extremely small nozzle clogging and the like suitable for ink jet recording by filtering with a micro filter as required.
Examples of the recording medium of the aqueous pigment dispersion and aqueous pigment recording liquid of the present invention include known and commonly used recording media such as plain paper, resin-coated paper, and synthetic resin films.
Further, in the case of an aqueous pigment recording liquid such as an aqueous ink for ink jet recording, an aqueous pigment recording liquid which can correspond to either of the piezo type and the thermal type can be prepared by appropriately preparing the composition according to the ejection type. You can get it.
EXAMPLES Hereinafter, the present invention will be described in detail by way of examples. However, these examples are intended to specifically describe the present invention, and the embodiments are not limited thereto.

  Next, the present invention will be specifically described with reference to synthesis examples, examples and comparative examples. Hereinafter,% means mass% and parts mean parts by mass unless otherwise noted.

(Production Example 1: Production of aqueous polyurethane PUD-1)
A 4-neck flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen blow-in tube under a nitrogen stream, polycarbonate diol 1 based on 1,6-hexanediol / 1,4-butanediol (weight average molecular weight: 2 000, 964 parts by mass, 43 parts by mass of dimethylol propionic acid and 558 parts by mass of methyl ethyl ketone were uniformly mixed. Subsequently, 295 parts by mass of dicyclohexylmethane diisocyanate is added, 0.05 parts by mass of tin dioctylate is added, and the mixture is reacted at 70 ° C. for about 4 hours to obtain a methyl ethyl ketone solution of urethane prepolymer 1 having isocyanate groups at molecular ends. Obtained. In the urethane prepolymer 1 having an isocyanate group at its molecular terminal, 6.2 parts by mass of 2- (2-hydroxy-5-t-butylphenyl) -2H-benzotriazole as an ultraviolet absorber, as a light stabilizer, 6.2 parts by mass of poly- (N-β-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidyl succinate), as an antioxidant, ethylenebis (oxyethylene) bis [3- 3.8 parts by mass of (5-tert-butyl-4-hydroxy-m-tolyl) propionate] and 1.3 parts by mass of triphenyl phosphite were added and dissolved.

  After 33 parts by mass of triethylamine was added to the methyl ethyl ketone solution 1 of the urethane prepolymer 1 obtained above to neutralize the carboxyl group in the urethane prepolymer 1, 2,516 parts by mass of ion exchanged water was gradually added. Next, 19 parts by mass of ethylenediamine was added and reacted. After completion of the reaction, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous polyurethane PUD-1 (nonvolatile content: 35.0% by mass).

Production Example 2 Production of Aqueous Polyurethane PUD-2
A 4-neck flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen blow-in tube under a nitrogen stream, polycarbonate diol 1 based on 1,6-hexanediol / 1,4-butanediol (weight average molecular weight: 2 1,000 parts by weight, and 64 parts by weight of polycarbonate diol 2 (weight-average molecular weight: 2,000) based on 1,6-hexanediol, and 53 parts by weight of dimethylol propionic acid and 559 parts by weight of methyl ethyl ketone, uniformly Mixed. Next, 287 parts by mass of dicyclohexylmethane diisocyanate is added, 0.05 parts by mass of tin dioctylate is added, and the mixture is reacted at 70 ° C. for about 4 hours to obtain a methyl ethyl ketone solution of urethane prepolymer 2 having isocyanate groups at molecular ends. I got In the urethane prepolymer 2 having an isocyanate group at its molecular terminal, 5.2 parts by mass of 2- (2H-benzotriazol-2-yl) -p-cresol as a UV absorber, 5.2 parts by mass of a poly- (light stabilizer) 5.2 parts by mass of N-β-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidyl succinate), and as an antioxidant, 3,9-bis (2- (3- (3 (3) -Tert-Butyl-4-hydroxy-5-methylphenyl) -propionyloxy) -1,1-dimethylethyl) -2,4,8,10-tetraoxo-spiro (5,5) undecene 5.2 parts by mass And 3.9 parts by mass of triphenyl phosphite were added and dissolved.

  40 parts by mass of triethylamine was added to the methyl ethyl ketone solution of the urethane prepolymer 2 obtained above to neutralize carboxyl groups in the urethane prepolymer 2, and then 2,482 parts by mass of ion exchanged water was added. Subsequently, 13 parts by mass of ethylenediamine was added and reacted. After completion of the reaction, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous polyurethane PUD-2 (nonvolatile content: 35.0% by mass).

Production Example 3 Production of Aqueous Polyurethane PUD-3
A four-necked flask equipped with a stirrer, reflux condenser, thermometer and nitrogen bubbler under a nitrogen stream, 964 parts by mass of polytetramethylene glycol (weight average molecular weight: 2,000), 43 parts by mass of dimethylol propionic acid And 558 parts by mass of methyl ethyl ketone were added and uniformly mixed. Next, 295 parts by mass of dicyclohexylmethane diisocyanate is added, 0.1 parts by mass of tin dioctylate is added, and the reaction is carried out at 70 ° C. for about 4 hours to obtain a methyl ethyl ketone solution of urethane prepolymer 3 having isocyanate groups at molecular ends. I got

  33 parts by mass of triethylamine was added to the methyl ethyl ketone solution of the urethane prepolymer 3 obtained above to neutralize carboxyl groups in the urethane prepolymer, and then 2,453 parts by mass of ion exchanged water was added. Next, 19 parts by mass of ethylenediamine was added and reacted. After completion of the reaction, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous polyurethane PUD-3 (nonvolatile content: 35.0% by mass).

[Production of pigment dispersion stock solution]
Ratio of isopropyl alcohol and methyl ethyl ketone containing 500 parts of CI Pigment Yellow 74 (manufactured by Sanyo Dye) and acrylic resin (manufactured by DIC Corporation, 43.4% of styrene-acrylic resin) in a mixing tank equipped with a cooling jacket 173 parts of a solution of 8: 2), 51 parts of a 25% aqueous solution of sodium hydroxide, 152 parts of methyl ethyl ketone and 1320 parts of ion-exchanged water were charged and mixed by stirring with a three-one motor for 1 hour. The obtained mixed solution is passed through a dispersing device (SC mill SC 100/32, manufactured by Mitsui Mining Co., Ltd.) filled with zirconia beads having a diameter of 0.3 mm, and the dispersion solution from the dispersing device is mixed into a mixing tank. It disperses by return method). During the dispersion process, cold water was passed through a cooling jacket and controlled so that the dispersion temperature was maintained at 30 ° C. or less, and the rotor peripheral speed of the dispersion apparatus was fixed at 11.25 m / sec and dispersed for 2 hours. After completion of the dispersion, the undiluted dispersion was withdrawn from the mixing vessel, and then the mixing vessel and the flow path of the dispersing device were washed with 1,400 parts of water and combined with the undiluted dispersion to obtain a mill dispersion.
The mill dispersion was placed in a glass distillation apparatus, and all of isopropyl alcohol and methyl ethyl ketone and part of water were distilled off. After cooling to room temperature, 2% hydrochloric acid was added dropwise while stirring to adjust to pH 4.5, and then the solid content was filtered and washed with a Nutsche-type filter device. The cake was taken in a container, and a 25% aqueous solution of sodium hydroxide was added thereto, and then redispersed with a disper (TK homodisper 20 type, manufactured by Tokushu Kika Kogyo Co., Ltd.). Further, water was added to adjust the non-volatile content to 23% by weight, and the mixture was centrifuged at 6,000 G for 30 minutes to obtain a yellow aqueous pigment dispersion stock solution.

Example 1
An aqueous pigment dispersion stock solution, a polyurethane resin aqueous dispersion according to Production Example 1, Proxel GXL (S) as an antiseptic agent, and ion-exchanged water, pigment content 13%, polyurethane resin non-volatile content in mass conversion An aqueous pigment dispersion 1 was prepared of 2.6% and 0.2% Proxel GXL (S).

Example 2
An aqueous pigment dispersion stock solution, a polyurethane resin aqueous dispersion according to Production Example 1, Proxel GXL (S) as an antiseptic agent, and ion-exchanged water, pigment content 13%, polyurethane resin non-volatile content in mass conversion An aqueous pigment dispersion 2 was prepared of 7.8% and Proxel GXL (S) 0.2%.

[Example 3]
An aqueous pigment dispersion stock solution, a polyurethane resin aqueous dispersion according to Production Example 1, Proxel GXL (S) as an antiseptic agent, and ion-exchanged water, pigment content 13%, polyurethane resin non-volatile content in mass conversion An aqueous pigment dispersion 3 of 13% and 0.2% Proxel GXL (S) was prepared.

Example 4
A pigment content rate of 13% and a polyurethane resin nonvolatile matter content ratio in mass conversion using an aqueous pigment dispersion stock solution, a polyurethane resin aqueous dispersion of Production Example 2, Proxel GXL (S) as an antiseptic agent, and ion exchanged water An aqueous pigment dispersion 4 of 2.6% and Proxel GXL (S) 0.2% was prepared.

Comparative Example 1
An aqueous pigment dispersion stock solution, a polyurethane resin aqueous dispersion of Production Example 3, Proxel GXL (S) as an antiseptic agent, and ion exchanged water, and the pigment content rate of 13% and the polyurethane resin nonvolatile matter content rate in mass conversion An aqueous pigment dispersion 5 of 2.6% and 0.2% Proxel GXL (S) was prepared.

Comparative Example 2
An aqueous pigment dispersion stock solution, Tinuvin 479-DW (manufactured by BASF, hydroxyphenyl triazine ultraviolet absorber dispersed in water), Tinuvin 123-DW (manufactured by BASF, N-OR type hindered amine light stabilizer dispersed in water), 13% of pigment content rate, 1.3% of Tinuvin 479-DW nonvolatile matter content rate and 1.3% of Tinuvin 123-DW nonvolatile matter content rate in mass conversion using Proxel GXL (S) and ion exchange water as preservatives And Proxel GXL (S) 0.2% aqueous pigment dispersion 6 were prepared.

  Each of the obtained aqueous pigment dispersions 1 to 6 was fitted to the composition shown below and prepared, and this was used for the following performance evaluation.

<Composition>
Aqueous pigment dispersion 31 parts 1,2-hexanediol 5 parts Glycerin 10 parts Surfynol 465 (manufactured by Air Products & Chemical Co.) 1 part Ion-exchanged water remaining

<Performance evaluation>
How to measure saturation:
The ink was filled in a cartridge of a commercially available ink jet printer (EM-930C, manufactured by Seiko Epson Corporation). Media were printed using photographic paper (GL-101 A450, manufactured by Canon Inc.). In addition, Duty printed 100%. The obtained printed matter was used to determine saturation C * using a SpectroEye (manufactured by Gretag Macbeth). The larger the saturation value, the better.
How to measure light resistance:
It printed so that OD was 0.5 using the above-mentioned printer media. The light resistance test of the printed matter was carried out for 100 hours in accordance with JEITA CP3901 standard using SUNTEST CPS + (manufactured by Toyo Seiki Co., Ltd.). The color difference (√ ((a * -a ₀ *) ^{^ 2} + (b *-b ₀ *) ^{^ 2} + (L *-L ₀ *) ^{^ 2} )) before and after the light resistance test was used as an indicator of light resistance. . The smaller the color difference, the better.

  The present invention (Examples 1 to 4) exhibited remarkably excellent chroma and light resistance as compared with Comparative Example 1 using a urethane containing no ultraviolet light absorber and no light stabilizer. In addition, the present invention (Examples 1 to 4) exhibited excellent chroma and light fastness as compared to Comparative Example 2 corresponding to the method described in Patent Document 1 listed in the prior art column.

Claims (5)

With pigments,
(Meth) acrylic ester resin (A),
A polycarbonate-modified urethane resin (B) containing an ultraviolet absorber (B-1) and a light stabilizer (B-2),
An aqueous pigment dispersion characterized by containing at least. The polycarbonate-modified urethane resin (B) containing the ultraviolet light absorber (B-1) and the light stabilizer (B-2) further contains an antioxidant (B-3). The aqueous pigment dispersion as described in 1. The content of each of the ultraviolet absorber (B-1) and the light stabilizer (B-2) is 0.05% by mass or more and 0.7% by mass or less with respect to the pigment. Aqueous pigment dispersion as described. The content of each of the ultraviolet absorber (B-1), the light stabilizer (B-2), and the antioxidant (B-3) is 0.05% by mass or more with respect to the pigment. The aqueous pigment dispersion according to claim 2, which is 7% by mass or less. An aqueous ink for ink jet recording comprising the aqueous pigment dispersion according to any one of claims 1 to 4.