JP2000154227A - Aqueous polyurethane dispersant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a dispersant which, even when used in a small amount, can stably disperse a pigment to form an aqueous pigment dispersion excellent in storage stability by using a polyisocyanate compound having a specified average NCO functionality as the starting material and introducing anionic groups into the NCO groups through urethane bonds. SOLUTION: The starting material used is a polyisocyanate compound having an average NCO functionality of above 2, desirably, 2.1-20, desirably having an aromatic ring and/or having an isocyanurate ring, and/or being tolylene diisocyanate. Anionic groups, desirably, sulfo groups are introduced into the NCO groups through urethane bonds. A desirable method for introducing anionic groups consists of reacting a compound containing at least one active H group and at least one anionic group in the molecule, (e.g. 2-hydroxyethoxybenzene-4- sulfonic acid) with a polyisocyanate compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an aqueous polyurethane-based dispersant. More specifically, the present invention relates to a polyurethane-based dispersant that can improve the dispersibility of a pigment in the production of paints and inks, and can further improve the storage stability and the like of aqueous pigment dispersions such as aqueous paints and aqueous printing inks. .

[0002]

2. Description of the Related Art Conventionally, in the production of water-based paints and water-based printing inks, for the purpose of improving the dispersibility, flowability, coloring power, and storage stability of pigments, preventing color separation, preventing sagging and preventing sedimentation. Various dispersants have been used. As these dispersants, in addition to surfactants, sodium phosphate of polyphosphoric acid, sodium salt of polyacrylic acid as a polymer dispersant,
Sodium ligninsulfonate, sodium salts of styrene-maleic acid copolymer, condensates of sodium naphthalenesulfonate and formalin, polyoxyethylene compounds and the like are generally used. However, the use of pigments has been diversified, and the demand for pigment dispersibility has been increasingly sophisticated, so that it has become difficult to obtain the desired dispersion quality with conventional dispersants.

On the other hand, polyurethane dispersants for water-based paints are disclosed in JP-A-6-200149 and JP-A-10-2009.
It has been proposed in, for example, JP-A-114866. For example, JP-A-6-200149 discloses a water-soluble polyurethane dispersion obtained by chain-extending an NCO-terminated urethane prepolymer having a hydrophilic group prepared so that the number of NCO functional groups is less than 2, using water and / or a polyamine. An agent is disclosed. JP-A-10-114866 discloses an aqueous urethane dispersant comprising a diol containing an anionic group (sulfonic acid group) and a diisocyanate.

However, in a medium having a high dielectric constant such as water, a polar group having a high concentration is required in order to exhibit an electrostatically high dispersion stabilizing effect.
If an attempt is made to contain a large amount of the acidic functional group, there is a problem that the viscosity is remarkably increased, or the solution is precipitated and becomes cloudy. In addition, since hydrophilic groups contributing to the improvement of dispersibility are widely distributed in molecular terminals and molecular chains, the affinity for pigments is not sufficient, and the dispersibility and storage stability of aqueous paints or aqueous printing inks are not always sufficient. There was no.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aqueous dispersant which has excellent storage stability as an aqueous paint or aqueous ink and can stably disperse a pigment with a small amount of the pigment. And an aqueous pigment dispersion using the same.

[0006]

The present inventors have made intensive studies on the improvement of the affinity between the dispersant and the pigment, the water solubility of the dispersant, and the storage stability of the aqueous pigment dispersion.
The inventors have found that the above-mentioned problems can be solved by assuming that the isocyanate group of a polyisocyanate compound having an average number of isocyanate groups in one molecule having a specific value has a specific substituent introduced through a urethane bond. The present invention has been reached.

That is, the gist of the present invention is that a polyisocyanate compound (A) having an average number of isocyanate groups in one molecule of more than 2 is used as a raw material, and an anionic group (B) is introduced into the isocyanate group via a urethane bond. Water-based polyurethane-based dispersant, characterized in that Another aspect of the present invention resides in an aqueous pigment dispersion containing the coloring pigment and the aqueous polyurethane dispersant.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. It is essential that the polyisocyanate compound (A) to be used in the present invention has an average number of functional groups in one molecule of more than 2. The preferred average number of functional groups is 2.1
-20, more preferably 3-10. When this value is 2 or less, the introduction amount of the anionic group decreases,
Good storage stability cannot be obtained. If this value is too large, the number of branches increases, which may cause gelation.

Specific examples of the polyisocyanate compound (A) having an average number of isocyanate groups of more than 2 include a polyisocyanurate compound obtained by trimerization of a polyisocyanate compound, an organic diisocyanate and a polyfunctional active hydrogen compound. Isocyanate group-terminated polyurethane polyisocyanate compound, polyurea polyisocyanate compound and the like obtained by the reaction of For example, when carbon black is used as the pigment, a polyisocyanurate compound having a high affinity for the carbon black surface is preferable.

The polyisocyanurate compound of the present invention can be produced by a conventionally known production method. Usually, the reaction is carried out by reacting an organic diisocyanate in the presence of an isocyanuration catalyst. As organic diisocyanates, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,4-xylylene diisocyanate, 1,3
-Xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 3,3'-dimethyldiphenylmethane
4,4'-diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-
Diisocyanate, 3,3'-dimethoxydiphenyl-
4,4'-diisocyanate, α, α, α ', α'-tetramethylxylylene diisocyanate, polyphenylenepolymethylene polyisocyanate, carbodiimide-modified 4,4'-diphenylmethane diisocyanate,
Aromatic diisocyanate such as ureton imine modified product, aliphatic diisocyanate such as tetramethylene diisocyanate, hexamethylene diisocyanate, 2-methylpentane-1,5-diisocyanate, lysine diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene Alicyclic diisocyanates such as diisocyanate and hydrogenated diphenylmethane diisocyanate;

When carbon black is used as a pigment among these organic diisocyanates, aromatic diisocyanates having a high affinity for carbon black are preferred, and most preferred are 2,4 and / or 2,6.
It is tolylene diisocyanate. As such an isocyanuration catalyst, conventionally known ones can be used, and specific examples thereof include 2,4,6-tris (dimethylaminomethylphenol), triethylamine, N,
N ′, N ″ -trisdimethylaminopropylhexahydrotriazine, tetraalkylalkylenediamine,
Tertiary amines such as diazabicyclooctane and lower alkyl-substituted products thereof, tertiary amines and ethyl alcohol, mono-substituted carbamates, aldehydes, alkylene oxides, alkylene imines, ethylene carbonate, 2,3-butanedione and the like. A catalyst combined system, tertiary alkyl phosphines, tetramethyl ammonium, tetraethyl ammonium, quaternary alkyl ammonium hydroxide such as tetrabutyl ammonium,
Quaternary ammonium salts such as hydroxides of hydroxyalkylammonium such as trimethylhydroxypropylammonium, trimethylhydroxyethylammonium and triethylhydroxypropyl; alkali metal salts of imides such as potassium phthalimide;
A quaternary onium hydroxy compound of P, As or Sb,
Onium compounds such as onium hydroxy compounds of S or Se; alkyl-substituted ethylene imines such as N-methylethylene imine; potassium acetate, sodium acetate;
Metal salts of carboxylic acids such as lead ethylhexanoate, sodium benzoate, potassium naphthenate and magnesium naphthenate; oxides, hydroxides, carbonates, enol compounds and phenolic metal salts of alkali metals and alkaline earth metals Epoxy compounds, a combination system of an epoxy compound and a tertiary amine, a co-catalyst such as a metal salt of an aromatic secondary amine such as a sodium salt of diphenylamine, titanium tetrabutylate, tributyl antimony oxide, etc. Various organic metals, aluminum chloride, Friedel-Crafts catalysts such as boron trifluoride, chelate compounds of alkali metals such as sodium salicylaldehyde,
Metal chelates of β-diketones such as aluminum acetylacetone and lithium acetylacetone are exemplified. Among the above isocyanuration catalysts, N,
Preferred are tertiary amines such as N ′, N ″ -trisdimethylaminopropylhexahydrotriazine, and metal salts of carboxylic acids such as sodium acetate, cobalt acetate, potassium naphthenate and magnesium naphthenate.

The concentration of the isocyanurate catalyst varies depending on the catalyst used and the reaction temperature, but is usually selected from the range of 0.001 to 10% by weight based on the polyisocyanate. In addition to the above catalysts, co-catalysts include aliphatic alcohols such as methanol, ethanol and butanol, polyhydric alcohols such as ethylene glycol, 1,3-butanediol, neopentyl glycol and trimethylolpropane, and polyhydric alcohols such as polypropylene glycol. It is preferred that ethers, phenols, secondary amines, imidazoles and the like are used in combination usually at 0.05 to 10% by weight based on the polyisocyanate.

[0013] Alcohols such as aliphatic alcohols, polyhydric alcohols and phenols can be added simultaneously with the isocyanuration catalyst, or after reacting with an organic diisocyanate to form a urethane bond, It is also possible to carry out a chemical reaction. The reaction temperature for the isocyanuration is generally selected from the range of 0 to 200 ° C, preferably 0 to 100 ° C.

The reaction may or may not use a solvent.
The solvent used is an inert solvent commonly used in polyurethane production, for example, aromatic solvents such as toluene and xylene, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, and esters such as ethyl acetate, butyl acetate and isobutyl acetate. Solvents, glycol ether ester solvents such as ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, 3-methyl-3-methoxybutyl acetate, and ethyl-3-ethoxypropionate; ether solvents such as tetrahydrofuran and dioxane; One or more aprotic polar solvents such as N-methylpyrrolidone can be used. The type of solvent used,
By selecting the amount and the resin concentration, the viscosity can be adjusted according to the use conditions.

The progress of the reaction can be monitored by measuring the NCO content of the reaction solution, measuring the infrared spectrum, measuring the refractive index, and the like. When a predetermined NCO content or isocyanurate conversion rate is reached, the reaction is stopped with a polymerization terminator suitable for each catalyst. Examples of the reaction terminator include inorganic acids such as hydrochloric acid, phosphoric acid, and phosphorous acid; phosphates such as monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, dimethyl phosphate, diethyl phosphate, and dibutyl phosphate; Monomethyl phosphate, monoethyl phosphite, monobutyl phosphite,
Phosphites such as dimethyl phosphite, diethyl phosphite, dibutyl phosphite, methanesulfonic acid, p-toluenesulfonic acid, methyl p-toluenesulfonate, p
-Sulfonic acids such as ethyl toluenesulfonate or alkyl esters thereof, and perfluorinated sulfonic acids such as nonafluorobutanesulfonic acid. The amount of the polymerization terminator to be added is preferably in the range of equivalent to twice the amount of the added catalyst.

Usually, it can be used without removing the unreacted monomer, but it may contain a large amount of unreacted monomer depending on the isocyanuration rate. When the unreacted monomer has an adverse effect, it is possible to remove the unreacted monomer by using thin film distillation or the like. Further, it is also possible to obtain a polyisocyanurate compound by reacting a compound containing an active hydrogen group and an anionic group in one molecule described later with polyisocyanate and then performing an isocyanuration reaction.

In producing the polyisocyanurate compound of the present invention, a polyfunctional hydroxy compound may be used to such an extent that pigment dispersibility and water solubility are not impaired.
The polyfunctional hydroxy compound may be subjected to an organic diisocyanate reaction before the isocyanuration reaction, or may be reacted after the isocyanuration reaction. Examples of the polyfunctional hydroxy compound include glycerin, trimethylolpropane, trimethylolethane, 1,2,6
Tri- or higher functional polyhydric alcohols such as hexanetriol, 1,2,4-butanetriol, erythritol, sorbitol, pentaerythritol, dipentaerythritol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol,
Tripropylene glycol, 1,2-butanediol,
1,3-butanediol, 1,4-butanediol,
2,3-butanediol, 2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-butyl- 2-ethyl-1,3-propanediol, 1,5-pentanediol, 3-methyl-1,
5-pentanediol, 2-methyl-2,4-pentanediol, 1,6-hexanediol, 2-ethyl-
1,3-hexanediol, neopentyl glycol,
1,3,5-trimethyl-1,3-pentanediol,
2,2,4-trimethyl-1,3-pentanediol,
1,8-octanediol, 1,9-nonanediol,
Aliphatic glycols such as 2-methyl-1,8-octanediol, 1,4-cyclohexanediol, 1,4-
Alicyclic glycols such as cyclohexanedimethanol,
Examples include monomer glycols such as aromatic glycols such as xylylene glycol and bishydroxyethoxybenzene, and high molecular weight polyols such as polyether polyol, polyester polyol, polyether ester polyol, polycarbonate polyol and acrylic polyol.

Examples of the polyether polyol include glycols such as ethylene glycol, propylene glycol and diethylene glycol; polyols having three or more functional groups such as glycerin, trimethylolethane, trimethylolpropane and pentaerythritol; and polyamines such as ethylenediamine and toluenediamine. And polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide and propylene oxide, and polytetramethylene ether glycols obtained by ring-opening polymerization of tetrahydrofuran.

Examples of the polyester polyol include dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid and phthalic acid; tri- and tetracarboxylic acids such as trimellitic acid and pyromellitic acid; ethylene glycol and propylene glycol. 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5 pentanediol, 2,2-diethylpropanediol,
2-ethyl-2-butylpropanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, 1,4-cyclohexanediol, 1,4
-A diol such as cyclohexanedimethanol, or a triol such as trimethylolpropane or glycerin; or a product obtained by a polycondensation reaction with bisphenol A or bisphenol F.

The polyetherester polyol can be obtained by reacting a mixture with an ether group-containing diol or another glycol with the above-mentioned dicarboxylic acid or anhydride thereof, or by subjecting an alkylene oxide to addition polymerization of polyester glycol. Such as poly (polytetramethylene ether) adipate.

Examples of the above polycarbonate polyol include a dealcoholization condensation reaction of a polyhydric alcohol with a dialkyl carbonate such as dimethyl carbonate and diethyl carbonate, a phenol condensation reaction of a polyhydric alcohol with a diphenyl carbonate, and a dehydration reaction of a polyhydric alcohol with ethylene carbonate. It is obtained by a glycol condensation reaction or the like. Examples of the polyhydric alcohol include 1,6-hexanediol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol,
2,2-diethylpropanediol, 2-ethyl-2-
Examples thereof include aliphatic diols such as butylpropanediol and neopentyl glycol, and alicyclic diols such as 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol.

When producing a polyisocyanurate compound, hexamethylenediamine, xylenediamine,
Diamines such as isophoronediamine and N, N-dimethylethylenediamine, and aminoalcohols such as monoethanolamine and diethanolamine can also be used in combination. In the present invention, the anion group (B) reacts with an anion group or a base to form an anion group. In this case, the anion is converted into an anion group by neutralizing with a base before, during or after the reaction. There is no particular limitation as long as it is a forming group, and examples thereof include conventionally known sulfonic acids, carboxylic acids, phosphoric acids, and salts thereof. When carbon black is used as a pigment among these, a metal sulfonic acid salt having good dispersibility is most preferable.

As a method for introducing an anionic group, a compound containing one or more active hydrogen groups and one or more anionic groups in one molecule is reacted with a polyisocyanate compound. The method of doing is general. The sulfonate is introduced into the polyisocyanate compound (A) of the present invention by a conventionally known production method. Specifically, the following method is mentioned.

(1) A method using a compound containing an active hydrogen group and a sulfonate in one molecule. Compounds containing sulfonic acid or a metal salt thereof as an anionic group include isethionic acid, p-hydroxybenzenesulfonic acid, and p-hydroxybenzenesulfonic acid.
-(2-hydroxyethoxybenzene) sulfonic acid, sulfanilic acid, 2-aminonaphthalene-6,7-disulfonic acid, 1-aminonaphthalene-3,6-disulfonic acid, or an alkali metal salt thereof in one molecule. 1
Compounds containing two active hydrogen groups and a sulfonic acid group,
N, N-dihydroxyethyl-2-aminoethanesulfonic acid, N, N-dihydroxypropyl-2-aminoethanesulfonic acid, 3-dihydroxyethyla-2-aminopropanesulfonic acid, 2,3-dihydroxynaphthalene-6 Sulfonic acid, 1,8-dihydroxynaphthalene-
Two active hydrogen groups in one molecule such as 3,6-disulfonic acid, 2,7-dihydroxynaphthalene-3,6-disulfonic acid, 1,7-dihydroxynaphthalene-3-sulfonic acid, or an alkali metal salt thereof. Examples include compounds containing a sulfonic acid group.

(2) After reacting a compound containing an active hydrogen group and a halogen element in one molecule with an isocyanate group of a polyisocyanate compound, the halogen is reacted with an alkali metal sulfite to introduce an alkali metal sulfonate. Method.

(3) After reacting a compound containing an active hydrogen group and an unsaturated bond in one molecule with an isocyanate group of a polyisocyanate compound, the compound is reacted with an alkali metal hydrogen sulfite to introduce an alkali metal sulfonate. And the like. It is also possible to use a method in which concentrated sulfuric acid is reacted with an aromatic ring (including an organic diisocyanate) to form a sulfonate and then neutralized with a base.

In the reaction between the active hydrogen group and the isocyanate group, an organic solvent may or may not be used. As the solvent to be used, one or two or more kinds of inert solvents commonly used in the production of polyurethane described above can be used. No particular catalyst is required during the reaction, but depending on the case, an organotin catalyst such as dibutyltin dilaurate or dibutyltin dioctoate, an organic lead catalyst such as lead octanoate, or triethylamine, dimethyloctylamine, diazatin It is also effective to use a catalyst of a tertiary amine compound such as bicycloundecene. The reaction temperature is generally selected from the range of 0 to 200 ° C, preferably 5 to 100 ° C.

When a polyisocyanate compound is reacted with an active hydrogen group and a halogen element or a compound containing an unsaturated bond, and then reacted with an alkali metal sulfite or an alkali metal bisulfite, the alkali metal sulfite is usually used. This is performed by dissolving an alkali metal bisulfite in water. When a reaction product of a polyisocyanate compound, an active hydrogen group and a halogen element or a compound containing an unsaturated bond is precipitated with water, a general organic solvent can be used. The reaction temperature is usually 0 to 150
° C, preferably in the range of 0 to 110 ° C.

There is no particular need to remove the organic solvent as long as the performance of the aqueous pigment dispersion is not impaired, but if a water-insoluble organic solvent is used, it can be removed by distillation under reduced pressure or the like. preferable. The aqueous polyurethane-based dispersant of the present invention described above can be used mainly as a dispersant for a coloring pigment.

In the aqueous pigment dispersion containing the coloring pigment of the present invention and the aqueous polyurethane-based dispersant, an inorganic pigment or an organic pigment is used as the coloring pigment. Examples of the inorganic pigments include black pigments such as carbon black, animal black, and graphite; white pigments such as titanium white, zinc white, lithopone, and lead white; and transparent white pigments such as calcium carbonate, barium sulfate, and calcium silicate. , Zinc pigments and other gray pigments,
Red pigments such as red iron and red lead molybdenum, brown pigments such as amber and iron oxide powder, yellow pigments such as graphite and iron oxide yellow, green pigments such as chromium oxide and viridian, ultramarine blue and dark blue Blue pigments, purple pigments such as Mars purple and light-mouthed cobalt purple, and metal powder pigments such as aluminum powder, copper powder, and bronze powder.

Examples of the organic pigment include natural organic pigments and synthetic organic pigments. Natural organic pigments include cochineal lake, madder lake and the like. Examples of the synthetic organic pigments include red pigments such as toluidine red and quinacrine red; yellow pigments such as fast yellow, anthraquinone yellow and benzine yellow; green pigments such as phthalocyanine green; and blue pigments such as phthalocyanine blue. . These pigments are used alone or in combination of two or more.

The pigment used in the present invention is preferably a black pigment, more preferably carbon black. The aqueous polyurethane-based dispersant of the present invention is used as a pigment dispersant for preparing an aqueous pigment liquid by dispersing a pigment, for example, a pigment and an aqueous polyurethane-based dispersant according to the present invention. Further depending on the water,
The aqueous pigment dispersion can be obtained by adding an organic solvent and a vehicle resin, stirring and mixing, and dispersing the mixture using a disperser. As the disperser, a sand grind mill, a ball mill, a roll mill, an attritor, a dissolver, and the like generally used in the paint industry and the ink industry can be used.

The aqueous pigment dispersion of the present invention may contain, if necessary, an aqueous resin such as an acrylic, vinyl acetate, vinyl chloride or urethane emulsion, an SBR or NBR latex, a fluororesin powder, or a silicon resin powder. Or organic modifiers such as urethane resin powder, hindered phenol-based, hydrazine-based, phosphorus-based, benzophenone-based, benzotriazole-based, oxalic acid anilide-based or hindered amine-based stabilizers, and polyacrylic acid-based dispersions Surfactants, surfactants such as ethylene oxide adducts of nonylphenol, defoamers such as silicon-based and fluorine-based defoamers, preservatives such as nitrogen-sulfur compounds or organic sulfur-halogen compounds, ethylene glycol, propylene glycol, etc. Antifreeze, cellulose derivatives, starch derivatives or Additives such as thickeners such as polyvinyl alcohol can be added. The aqueous pigment dispersion of the present invention has excellent pigment dispersion stability and is therefore suitably used as a coloring agent for aqueous paints or aqueous printing inks.

[0034]

The present invention will be described in more detail with reference to the following Examples, which by no means limit the scope of the present invention.
In the following, “part” indicates “part by weight” and “%” indicates “% by weight”.

Production Example 1 In a four-necked flask equipped with a thermometer, a cooler, a stirrer, and a dropping funnel, 80 tolylene diisocyanate (2,4- / 2,6-
90. Tolylene diisocyanate = 80/20 weight ratio)
97 parts and 90.97 parts of butyl acetate were added, and the internal temperature was adjusted to 25.
C., 0.36 parts of a 5% methanol solution of sodium acetate was added with stirring, and after stirring for 2 hours, the internal temperature was cooled to 5 ° C.

Then, 0.11 part of a 5% butyl acetate solution of N, N ′, N ″ -trisdimethylaminopropylhexahydrotriazine is added and reacted for 2 hours. Thereafter, 0.37 part of a 5% methanol solution of potassium acetate was gradually dropped, and when the isocyanate content reached 8.2%, 0.07 part of phosphoric acid was added as a reaction terminator to carry out the isocyanurate-forming reaction. The operation was stopped to obtain a polyisocyanate resin solution.

The obtained polyisocyanate resin solution 1
After raising the internal temperature to 25 ° C, 8% of sodium 2-hydroxyethoxybenzene-4-sulfonate was 8%.
817.15 parts of an N-methylpyrrolidone solution was slowly added dropwise, and the mixture was reacted at room temperature for 4 hours. After removing the solvent under reduced pressure at 100 ° C., a yellow solid having an SO ₃ Na content of 1.74 meq / g was obtained. Was. Water was added to this solid so as to have a resin solid content of 50% to obtain a pale yellow transparent liquid aqueous polyurethane dispersant.

Production Example 2 243.96 parts of the polyisocyanate resin solution obtained in the same manner as in Production Example 1 was adjusted to an internal temperature of 25 ° C.
756.04 parts of an 8% solution of sodium-hydroxyethoxybenzene-4-sulfonate in N-methylpyrrolidone was gradually added dropwise, and SO ₃ Na was produced in the same manner as in Production Example 1 below.
A light yellow transparent liquid aqueous polyurethane dispersant having a content of 1.38 meq / g (in terms of resin solids) was obtained.

Example 1 2 parts of an aqueous polyurethane-based dispersant, 5 parts of Mitsubishi Carbon Black MA600 (manufactured by Mitsubishi Chemical Corporation), 5 parts of N-methylpyrrolidone, and 88 parts of water were added to make 100 parts, and then glass beads ( An amount equivalent to 80% by volume (average particle size: 0.5 mm) was added, and this was dispersed in a paint shaker for 2 hours to obtain an aqueous pigment dispersion. afterwards,
The following evaluation tests were performed, and the results are shown in Table 1.

Example 2 An aqueous pigment dispersion was obtained in the same manner as in Example 1 except that 2 parts of an aqueous polyurethane-based dispersant was used. The following evaluation tests were performed, and the results are shown in Table 1.

Comparative Example 1 An aqueous pigment dispersion was obtained in the same manner as in Example 1, except that 5 parts of Mitsubishi Carbon Black MA600 (manufactured by Mitsubishi Chemical Corporation), 5 parts of N-methylpyrrolidone and 90 parts of water were used. . Thereafter, the following evaluation tests were performed, and the results are shown in Table 1.

<Evaluation method>-Solution storage stability (1) Solution properties: aqueous pigment dispersion was kept at room temperature for 1 day at 60 ° C.
For 7 days, and the presence or absence of sedimentation of the pigment was visually observed. (2) Particle size distribution: after one day at room temperature
Stored at 7 ° C for 7 days to determine the particle size distribution of MicotracUPA (Leeds & No.
rthrup) was used as the average particle diameter.

[0043]

[Table 1]

[0044]

The aqueous polyurethane dispersant of the present invention comprises:
In addition to exhibiting good coloring performance as a coloring agent for aqueous paints and aqueous printing inks, the pigments have excellent sedimentation stability during storage of paints and inks, and are extremely useful industrially.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J002 CK031 CK041 CK051 DA026 DA036 DA076 DC006 DE096 DE106 DE116 DE136 DE146 DE156 DE236 DG046 DJ006 FD096 GH01 4J034 CA02 CA03 CA04 CA05 CA13 CA31 CB01 CB03 CB04 CC23 CC52 CC52 CC52 CC52 CC52 CC52 CC23 DA01 DF02 DF16 DF17 DF20 DF22 DG06 DG14 EA07 HA07 HB06 HC03 HC12 HC13 HC17 HC22 HC35 HC46 HC64 HC66 HC67 HC70 HC71 HC73 KB03 RA07

Claims (10)

[Claims] 1. A polyisocyanate compound (A) having an average number of isocyanate groups in one molecule of more than 2 as a raw material, and an anionic group (B) introduced into the isocyanate group via a urethane bond. An aqueous polyurethane-based dispersant, characterized in that: 2. The aqueous polyurethane-based dispersant according to claim 1, wherein the polyisocyanate compound (A) has an aromatic ring. 3. The polyisocyanate compound (A) having an isocyanurate ring.
2. The aqueous polyurethane-based dispersant according to item 1. 4. The aqueous polyurethane-based dispersant according to claim 1, wherein the polyisocyanate compound (A) is tolylene diisocyanate. 5. The aqueous polyurethane-based dispersant according to claim 1, wherein the anionic group (B) is a sulfonic acid group. 6. The method according to claim 1, wherein the anionic group (B) is introduced by using a compound containing two or more active hydrogen groups and one or more anionic groups in one molecule. An aqueous polyurethane-based dispersant as described in Crab. 7. The aqueous polyurethane according to claim 1, wherein the anionic group (B) is introduced using a compound containing one active hydrogen group and an anionic group in one molecule. Dispersant. 8. An aqueous pigment dispersion comprising a coloring pigment and the aqueous polyurethane dispersant according to claim 1. 9. The aqueous pigment dispersion according to claim 8, wherein the coloring pigment is carbon black. 10. The aqueous pigment dispersion according to claim 8, which is used as a colorant for aqueous paints or aqueous printing inks.