JPH0977986A - Aqueous pigment dispersant, pigment composition containing the same, and aqueous pigment dispersion - Google Patents

Abstract

(57) Abstract: A water-based pigment dispersant that can favorably disperse a pigment in an aqueous system and can be industrially advantageously produced, a pigment composition using the same, and an aqueous pigment dispersion. To provide. An aqueous pigment dispersant having an organic dye only at the terminal of an aqueous linear urethane polymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dispersant for pigment particles, and more specifically, a water-based pigment dispersant for improving suitability for use in water-based printing inks and water-based paints, and a pigment containing the same. Compositions, as well as aqueous pigment dispersions.

[0002]

2. Description of the Related Art In recent years, water-based paints and inks have been made more and more responsive to increasing needs for resource protection, environmental protection, improvement of work stability and the like. The required quality of water-based paints and water-based inks is, like oil-based paints and oil-based inks, fluidity, storage stability, film gloss, sharpness, tinting strength and the like. However, most pigments are far inferior in aptitude such as pigment dispersibility to an aqueous vehicle as compared with the case of being oily, so that a satisfactory quality cannot be obtained by a usual dispersion method.
Therefore, the use of various additives such as a water-based pigment dispersion resin and a surfactant has been studied so far, but it satisfies all the above-mentioned suitability and is comparable to existing oil-based paints or oil-based inks having high quality. Quality is not obtained. Japanese Patent Application Laid-Open No. 7-41689 discloses a polymer-type dispersant in which an organic dye and a polymer are bound and described as an effective dispersant in an aqueous system. It is considered that this is because the interaction between the organic dye contained in the polymer-type dispersant and the pigment particles promotes the adsorption of the polymer-type dispersant to the pigment particles and improves the dispersibility. However, the polymer dispersant described in this publication uses a functional group randomly present in the polymer to bond the organic dye and the polymer. According to this method, since the organic dye is randomly introduced into the polymer, the affinity between the polymer portion and the dispersion medium is weakened, and it becomes difficult to secure an adsorption layer sufficient for dispersion stabilization. When the amount of the organic dye introduced into the dispersion medium increases, the solubility in the dispersion medium decreases, so that there is a problem that it becomes impossible to secure an adsorption layer sufficient for dispersion stabilization.

[0003]

DISCLOSURE OF THE INVENTION The present invention improves the above-mentioned various drawbacks, can disperse a pigment in an aqueous system favorably, and can be produced industrially advantageously, and a pigment dispersant for an aqueous system. The present invention provides a pigment composition used as well as an aqueous pigment dispersion.

[0004]

That is, the first invention is a water-based pigment dispersant having an organic dye only at the terminal of an aqueous linear urethane polymer, and the second invention is a pigment and a first invention. A pigment composition comprising the aqueous pigment dispersant of the invention. Furthermore, the third invention is an aqueous pigment dispersion comprising a pigment, the aqueous pigment dispersant of the first invention and an aqueous resin.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Since the pigment dispersant of the present invention has a structure having an organic dye only at one end or both ends of the polymer part, the organic dye can be efficiently adsorbed on the pigment surface, and the polymer part and the dispersion medium can be efficiently adsorbed. Due to its good affinity with
The adsorption between the pigment and the organic dye can be efficiently stabilized. Further, in terms of the synthetic method, by using the end of the polymer, a small amount of organic dye can be introduced into the polymer with high accuracy.

Hereinafter, the present invention will be described in detail. Of the present invention
Pigment dispersant is only on the ends of aqueous linear urethane polymers.
It has an organic dye. The aqueous linear urethane-based heavy
The coalesced is at least two that can react with isocyanate groups
And has a functional group of -COOH, -COONa,-
COONH_Four, -SO _ThreeH, -SO_ThreeNa, -SO_ThreeN
H_FourA compound having at least one hydrophilic group in the molecule
Dihydroxy compounds and dia
Do not allow the min compound to react with the diisocyanate compound.
It is a linear urethane polymer. For example, isocyanate
Having at least two functional groups capable of reacting with
Having at least one hydrophilic group in the molecule
As dimethylolpropionic acid, amino acids and amino acids
Nosulfonic acid and their oxyalkylated products and
And polyester products, diaminocarboxylic acid, diamid
Sodium nobenzenesulfonate, glycerin monophosphoric acid
Compounds such as the ester disodium salt may be mentioned. This
Dihydroxy compounds containing these compounds as essential components
Reacting a substance or a diamine compound with an isocyanate group,
As described below, urethane type containing terminal isocyanate groups
Polymer or urethane type with amino group at the end
A polymer is obtained. Urethane containing these terminal isocyanate groups
Polymers and urethane polymers with amino groups at the ends
Are those containing various hydrophilic groups as described above.
And the hydrophilic group can make the urethane polymer aqueous.
Things.

The pigment dispersant of the present invention can be obtained by the following two production methods. That is, the first method is to react a dihydroxy compound and a diisocyanate compound having at least two hydroxyl groups and containing as an essential component a compound having at least one of the various hydrophilic groups in the molecule as described above, A urethane polymer containing a terminal isocyanate group is prepared, and this linear urethane polymer is reacted with an organic dye having at least one reactive group selected from a primary amino group, a secondary amino group and a hydroxyl group. In general, the method is to remove the solvent after the reaction and replace with a water system.

In the second method, a dihydroxy compound and a diisocyanate compound are reacted to prepare a urethane polymer containing terminal isocyanate groups, and then a diamine compound is reacted to produce a urethane polymer having terminal amino groups. Is prepared, and this urethane polymer is reacted with a carboxyl group-introduced organic dye. In the case of the second method, the hydrophilic group in the aqueous linear urethane polymer may be allowed to be present in the terminal isocyanate group-containing urethane polymer by using a dihydroxy compound having a hydrophilic group as an essential component. Alternatively, by using a diamine compound having a hydrophilic group as one of the diamine compounds for chain extension, the diamine compound may be present in the urethane polymer having a terminal amino group.

The aqueous linear urethane polymer used in the present invention is obtained by reacting a dihydroxy compound with a diisocyanate compound and, if necessary, a diamine compound as described above. Examples of the dihydroxy compound include water, ethylene glycol, diethylene glycol, propylene glycol, butanediol, propanediol, 1,6-hexanediol, neopentyl glycol, cyclohexanedimethanol, etc., in addition to the dihydroxy compound having a hydrophilic group as described above. In addition to high molecular weight diols such as low molecular weight glycols, polyether diols, polyester diols, etc., bisphenols such as bisphenol A and bisphenol F, and alkylene oxides such as ethylene oxide and propylene oxide are added to bisphenol A and bisphenol F. Added glycols can also be used. Examples of the polyether diols include polymers, copolymers or graft polymers of alkylene oxides such as tetrahydrofuran, ethylene oxide, propylene oxide, butylene oxide, hexanediol, methylhexanediol, heptanediol, octanediol or these. There are polyether glycols by condensation of a mixture of, and propoxylated or ethoxylated polyether glycols. Polyester diols include ethylene glycol, propylene glycol,
1,3-butanediol, 1,4-butanediol, neopentyl glycol, hexanediol, methyl-1,5-pentanediol, octanediol, cyclohexanediol, 2-ethyl-1,3-hexanediol, bisphenol A, Diethylene glycol, triethylene glycol,
Development of cyclic ester compounds such as polyester diol and ε-caprolactone obtained by condensation reaction of saturated or unsaturated low molecular weight glycol such as dipropylene glycol and aliphatic or aromatic dibasic acid or aromatic dibasic acid ester There are polyester diols, polycarbonate diols, silicon diols and the like obtained by ring polymerization, and reaction products of terminal hydroxyl groups obtained by reaction of these with diisocyanate can also be used.

As the diisocyanate compound, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, 1,5-naphthalene diisocyanate, isophorone diisocyanate, dimeryl diisocyanate, lysine diisocyanate, hydrogenated 4,4 A diisocyanate such as'-diphenylmethane diisocyanate or hydrogenated tolylene diisocyanate, or an isocyanate adduct at both ends of these and glycols or amines, or a mixture thereof is used.

The synthesis conditions for the reaction of the dihydroxy compound and the diisocyanate compound are that the reaction temperature is room temperature to 140 ° C., preferably 40 to 100 ° C. Further, the equivalent ratio of the isocyanate group to the hydroxyl group is appropriately in the range of about 1.02: 1 to about 2: 1, preferably about 1.05: 1 to about 1.5: 1. If necessary, a conventionally known urethanization catalyst such as dibutyltin dilaurate, tin octylate, triethylamine, N, N-dimethylbenzylamine, sodium hydroxide, diethylzinc tetra (n-butoxy) titanium, etc. may be used. You can These reactions can be carried out in the absence of a solvent, but an organic solvent inert to isocyanate can be used for the purpose of homogenizing the reaction and adjusting the viscosity. Examples of such a solvent include acetone, methyl ethyl ketone, ethyl acetate, dioxane, acetonitrile, tetrahydrofuran, diglyme, N-methylpyrrolidone and the like, and these solvents may be used alone or in a mixed system.

As the diamine compound used for chain extension of the isocyanate-terminated urethane polymer by the second method, ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylene other than those having the above-mentioned hydrophilic group. Diamine, 1,7-diaminoheptane, 1,8-diaminooctane, xylylenediamine, 1,
Diamines such as 4-diaminocyclohexane, isophoronediamine, phenylenediamine and polyamidoamine,
Alternatively, a reaction product of a terminal amino group obtained by reacting these with an organic diisocyanate compound can be used.

In the step of extending the chain of the terminal isocyanate urethane polymer with the diamine compound, a solution prepared by diluting the diamine compound with the inert organic solvent may be added dropwise to the terminal isocyanate group-containing urethane polymer. Conversely, the terminal isocyanate group-containing urethane polymer may be added dropwise to the diamine compound solution for reaction. The amount of the diamine compound used is preferably in the range of more than 1 equivalent and not more than 2 equivalents relative to 1 equivalent of the free isocyanate groups in the urethane polymer containing a terminal isocyanate group. The reaction temperature is room temperature to 9 depending on the reactivity.
It can be performed in the range of about 0 ° C. In this way, the reaction between the urethane polymer having a terminal amino group, which is chain-extended with a diamine compound, and the organic dye having a carboxyl group is carried out by using water, alcohol, acetone or N, N.
In general, a method of reacting in a reaction solvent such as dimethylformamide in the presence of an alkali catalyst, removing the solvent, and substituting with an aqueous system is common. However, in the case of an azo pigment, a method in which a polymer having a terminal amine is previously reacted with a diazo component or a coupler component and then coupling is industrially advantageous.

The organic dyes used in the present invention include phthalocyanine type, insoluble azo type, azo lake type,
Anthraquinone type, quinacridone type, dioxazine type,
Diketopyrrolopyrrole, anthrapyrimidine, ansanthurone, indanthrone, flavanthrone,
Examples thereof include perinone-based, perylene-based, thioindigo-based, isoindolinone-based, benzimidazolone-based, and the like, which are introduced with a primary amino group, secondary amino group, hydroxyl group, carboxyl group or the like according to a conventional method. Is. For example,
Introducing a phthalimide group into an organic dye and then hydrolyzing it to introduce an amino group, or by diazotizing a hydroxyalkylaniline having various functional groups and then coupling it with various couplers to introduce a hydroxyl group. Or by introducing an acetoacetic acid arylide derivative from a hydroxyalkylaniline having various functional groups and then coupling it with various couplers to introduce a hydroxyl group.

The pigment dispersant of the present invention exerts an excellent dispersing effect on pigments which are generally commercially available. For example, soluble and insoluble azo pigments, azo pigments such as condensed azo pigments,
Phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, perylene / perinone pigments, dioxazine pigments, anthraquinone pigments, diketopyrrolopyrrole pigments, anthrapyrimidine pigments, ansanthrone pigments, indanthrone pigments , Organic pigments such as flavanthron-based pigments and thioindigo-based pigments, and inorganic pigments such as carbon black, titanium oxide, yellow lead, cadmium yellow, cadmium red, rouge, iron black, zinc white, navy blue, ultramarine it can. The content of the pigment dispersant of the present invention in the pigment is 0.5 to 100 parts by weight of the pigment.
100 parts by weight is preferred. If the amount is less than 0.5 parts by weight, the effect of dispersing the pigment is small, which is not preferable. Further, even if it is used in an amount of more than 100 parts by weight, the effect of the used amount cannot be obtained, and various coating film performance may be adversely affected.

The aqueous resin used in the aqueous pigment dispersion of the present invention is an acrylic copolymer, a styrene-acrylic acid copolymer, a styrene-maleic acid copolymer, an alkyd resin, an epoxy resin, a polyester resin. There are water-soluble resins or water-soluble resins such as urethane resins, but water-dispersed resins or water-soluble resins of acrylic copolymers are particularly preferable.

The water-dispersible resin or water-soluble resin of the acrylic copolymer may be one produced by emulsion polymerization, soap-free polymerization, suspension polymerization, or the like, or free polymerized in a hydrophilic organic solvent. It may be an aqueous dispersible resin obtained by neutralizing an acrylic copolymer resin having a carboxylic acid with ammonia or an organic amine and adding water. As the acrylic copolymer resin,
Emulsifying 50 to 80% by weight of (meth) acrylic acid alkyl ester, 5 to 30% by weight of carboxylic acid-containing monomer such as acrylic acid, methacrylic acid, maleic acid and itaconic acid, and 0 to 20% by weight of other monomer. Polymerization or solution polymerization in a hydrophilic organic solvent, weight average molecular weight 500
A resin having an acid value of 0 to 300,000 and an acid value of 1 to 200 is particularly preferable. Examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isopropyl (meth) acrylate, and (meth ) Isobutyl acrylate, 2-ethylhexyl (meth) acrylate, n-hexyl (meth) acrylate, and lauryl (meth) acrylate. Examples of the other monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, acrylamide, N-methylolacrylamide, diacetoneacrylamide, glycidyl (meth) acrylate,
Examples include styrene, vinyltoluene, vinyl acetate, acrylonitrile, vinyl alcohol, ethylene and the like.

The aqueous medium of the aqueous resin used in the present invention may be only water, but in some cases, an alcohol solvent such as ethyl alcohol, isopropyl alcohol, n-propyl alcohol, n-butanol, or ethylene. Water-miscible organic solvents such as glycols or mono- or dialkyl ethers of diethylene glycol can be admixed up to 50% by weight in the aqueous medium.

The amount of the aqueous resin used is preferably 5 to 500 parts by weight in terms of solid content based on 100 parts by weight of the pigment. In particular, when used as a concentrated dispersion, the aqueous resin is preferably 5 to 200 parts by weight in terms of solid content based on 100 parts by weight of the pigment, and when used as a paint or a printing ink,
Aqueous resin is 10 in terms of solid content based on 100 parts by weight of pigment.
0 to 500 parts by weight is preferred. If the amount of the aqueous resin is less than 5 parts by weight with respect to 100 parts by weight of the pigment, it becomes difficult to disperse the pigment, and if the amount of the aqueous resin is more than 500 parts by weight, the coloring is low and the pigment may not be suitable for use as a paint or a printing ink. When used as a paint or a printing ink, a curing agent resin such as a melamine resin, a curing catalyst, a surfactant or the like may be added.

The aqueous pigment dispersion of the present invention can be manufactured by the following method. 1. A pigment composition obtained by previously mixing a pigment and a pigment dispersant is added to an aqueous vehicle (that is, an aqueous resin and an aqueous medium) and dispersed. 2. A pigment and a pigment dispersant are added to an aqueous vehicle and dispersed. 3. A pigment and a pigment dispersant are separately dispersed in an aqueous vehicle in advance, and the resulting dispersion is mixed. In this case, the pigment dispersant may be dispersed only with the solvent. 4. After dispersing the pigment in the aqueous vehicle, the pigment dispersant is added to the obtained pigment dispersion. The desired effects can be obtained by any of these methods.

The pigment composition can be prepared by simply mixing the pigment powder and the pigment dispersant of the present invention to obtain a sufficient dispersing effect. A kneader, roll, attritor, supermill, various pulverizers, Mechanically mix with a disperser or the like, or add a solution containing the pigment dispersant of the present invention to a suspension system of water or an organic solvent for the pigment to deposit the pigment dispersant on the pigment surface, or strongly dissolve sulfuric acid or the like. Even better results can be obtained by performing a careful mixing method such as co-dissolving a strong organic pigment and a pigment dispersant and coprecipitating with a poor solvent such as water. In order to disperse the pigment or the pigment composition in the aqueous resin dispersion or solution, it is preferable to use a disperser such as a dissolver, a high speed mixer, a homomixer, a kneader, a roll mill, a sand mill, an attritor or the like.

[0022]

EXAMPLES The present invention will be described below based on examples.
In the examples, “parts” and “%” are “parts by weight” and “% by weight”, respectively.
Respectively.

Production Example 1 Polypropylene glycol (hydroxyl value 55 mg KOH / g) was placed in a four-necked flask equipped with a thermometer, a stirrer and a reflux condenser.
200 parts, dimethylol propionic acid 20.6 parts, N-
200 parts of methylpyrrolidone and 0.075 part of tin octylate are charged and heated to 80 ° C. under a nitrogen atmosphere while stirring. After refluxing for 1 hour, isophorone diisocyanate 69.
9 parts was added and the reaction was carried out at the same temperature for 4 hours to obtain an isocyanate-terminated prepolymer solution. Furthermore, the temperature of the reaction solution is set to
After cooling to 0 ° C., 441 parts of the prepolymer solution was dropped into a mixed solution of 12.1 parts of isophoronediamine and 180 parts of N-methylpyrrolidone, and then heated to 60 ° C. and reacted for 2 hours to obtain an amine-terminated polymer solution. Got This polymer had a number average molecular weight of 21,000 and an acid value of 30 mg KOH / g. Further, 22.2 parts of copper phthalocyanine carboxylic acid (containing an average of 1.2 carboxyl groups per molecule) was added to a mixture containing 400 parts of N-methylpyrrolidone and 8.5 parts of triethylamine, and the mixture was refluxed. And reacted for 2 hours. Unreacted materials and solvent were removed to obtain a paste containing 243 parts of compound (a).

Production Example 2 Polypropylene glycol (hydroxyl value 55 mg KOH / g) was placed in a four-necked flask equipped with a thermometer, a stirrer and a reflux condenser.
200 parts, dimethylol propionic acid 20.6 parts, N-
200 parts of methylpyrrolidone and 0.075 part of tin octylate are charged and heated to 80 ° C. under a nitrogen atmosphere while stirring. After refluxing for 1 hour, isophorone diisocyanate 64.
9 parts was added and the reaction was carried out at the same temperature for 4 hours to obtain an isocyanate-terminated prepolymer solution. The number average molecular weight of this polymer was 7,000 and the acid value was 30 mg KOH / g. Further, 400 parts of N-methylpyrrolidone and 73.0 parts of aminomethylcopper phthalocyanine were added and reacted at 80 ° C. for 4 hours. Unreacted materials and solvent were removed to give compound (b) 26
A paste containing 9 parts was obtained.

Production Example 3 Polypropylene glycol (hydroxyl value 55 mg KOH / g) was placed in a four-necked flask equipped with a thermometer, a stirrer and a reflux condenser.
200 parts, dimethylol propionic acid 20.6 parts, N-
200 parts of methylpyrrolidone and 0.075 part of tin octylate are charged and heated to 80 ° C. under a nitrogen atmosphere while stirring. After refluxing for 1 hour, isophorone diisocyanate 58.
7 parts was added and reacted at the same temperature for 4 hours to obtain an isocyanate-terminated prepolymer solution. This polymer had a number average molecular weight of 22,000 and an acid value of 30 mgKOH / g. Further, 400 parts of N-methylpyrrolidone and 22.3 parts of hydroxycopper phthalocyanine were added and reacted at 80 ° C. for 4 hours. Unreacted materials and solvent were removed to give compound (c) 233
A paste containing parts was obtained.

Production Example 4 22.2 parts of copper phthalocyanine carboxylic acid of Production Example 1 was changed to 10.7 parts of quinacridone carboxylic acid (containing an average of 1.5 carboxyl groups per molecule), and then synthesized. Unreacted materials and solvent were removed to give compound (d) 22
A paste containing 8 parts was obtained.

Production Example 5 After synthesizing 22.2 parts of copper phthalocyanine carboxylic acid of Production Example 1 to 16.6 parts of dioxazine carboxylic acid (containing 1.7 carboxyl groups on average per molecule), , Unreacted materials and solvent were removed to give compound (e) 21
A paste containing 3 parts was obtained.

Production Example 6 After 22.2 parts of copper phthalocyanine carboxylic acid of Production Example 3 was replaced with 12.3 parts of hydroxyquinacridone, synthesis was carried out.
Unreacted materials and solvent were removed to obtain a paste containing 218 parts of compound (f).

Production Example 7 400 parts of water was added to the solution containing 100 parts of the amine-terminated polymer obtained in Production Example 1 to prepare a suspension in which the solvent was replaced with water.
A compound obtained by reacting 2.3 parts of acetoacetylaminobenzenecarboxylic acid and a diazonium solution obtained by diazotizing 4,4-dichlorobenzidine by a conventional method are coupled by a conventional method to remove unreacted substances and a solvent, A paste containing 120 parts of compound (g) was obtained.

Examples 1 to 11 and Comparative Examples 1 to 7 As shown in Table 1, pigments, compounds (a) to (g) synthesized in Production Examples 1 to 7, water-soluble acrylic copolymer resin solutions ( A weight average molecular weight of 25,000, an acid value of 60 mg KOH / g, acrylic acid / 2-hydroxyethyl methacrylate / ethyl methacrylate / methyl methacrylate / vinyl acetate copolymer, solid content 20%) and ion-exchanged water are blended, After the dispersion, a melamine resin (“Cymel 303” manufactured by Mitsui Cytec Co., Ltd.) was blended to obtain a water-based acrylic resin / amino resin-based coating material. The resulting waterborne paint was spread on a PET film with a 4 mil film applicator and
Baking for 30 minutes at 0 ° C. As shown in Table 1, the system using the pigment dispersant of the present invention was superior to the system using no pigment dispersant in coating gloss because the pigment was dispersed more finely.

[0031]

[Table 1]

[0032]

INDUSTRIAL APPLICABILITY According to the present invention, in a pigment dispersion such as ink and paint, the dispersibility of the pigment is improved, the suitability for use such as non-aggregation and fluidity, the sharpness of the color tone of the coating, and the gloss are improved. It can be improved significantly.

Claims (3)

[Claims] 1. An aqueous pigment dispersant comprising an organic dye only at the terminal of an aqueous linear urethane polymer. 2. A pigment composition comprising a pigment and the water-based pigment dispersant according to claim 1. 3. An aqueous pigment dispersion comprising a pigment, the water-based pigment dispersant according to claim 1 and an aqueous resin.