JPS63154776A - Aqueous pigment dispersion - Google Patents

Abstract

PURPOSE:To obtain an aq. pigment dispersion which can be easily produced and has excellent storage stability, by using a copolymer composed of a specified macromonomer and a vinyl monomer as comonomer components as a dispersant for the aq. pigment dispersion. CONSTITUTION:An aq. pigment dispersion consist of a pigment, a dispersant and an aq. medium. The dispersant is an aq. dispersion of a copolymer obtd. by copolymerizing 3-98pts.wt. macromonomer (A) having at lest one polymerizable vinyl functional group selected from the group consisting of acryloyloxy, methacryloyloxy, allyloxy and arom. vinyl groups at one terminal thereof with 2-97pts.wt. vinyl monomer (B) having at lest one nitrogen-contg. heterocyclic ring selected from the group consisting of vinylpyrrodones, vinylimidazoles and vinylcabazoles, 0-20pts.wt. ethylenically unsaturated monomer (C) and 0-91pts.wt. alpha,beta-ethylenically unsaturated monomer (D) other than the components A to C.

Description

[Detailed description of the invention] The present invention is easy to manufacture using a novel dispersant.

The present invention also relates to an aqueous pigment dispersion having excellent storage stability.

Conventionally, in water-based paints such as emulsion paints and water-soluble resin paints containing pigments, the coloring effect on the painted surface decreases due to the difficulty of dispersing the pigments during manufacturing and the aggregation and sedimentation of the pigments during storage.
It is well known that undesirable phenomena such as flooding, floating, and loss of gloss occur. For this reason, generally, an aqueous pigment dispersion liquid in which pigments are dispersed with a dispersant is prepared in advance, and this dispersion is mixed and dispersed in the aqueous paint to be colored to color the aqueous paint.

In conventional aqueous pigment dispersions, low molecular weight compounds such as surfactants are used as dispersants, but these dispersants have negative effects, such as secondary adverse effects such as deterioration of coating performance or coating condition. This is unavoidable, and in recent years, oligomers or polymers having a medium molecular weight have been used as dispersants to suppress the deterioration of coating film performance.

However, when oligomers or polymers are used as dispersants, the amount used is larger than that of low-molecular surfactants, and the use of the resulting aqueous pigment dispersion depends on the type of binder used in the aqueous paint. There are drawbacks such as restrictions. This goes against the rationalization of paint manufacturing, and there is therefore a strong demand for the development of a water-based pigment dispersion that is common to various water-based paints.

Conventionally, as a dispersant component that can easily disperse pigments in small amounts, is compatible with various water-based resins, and is polymeric in itself and does not cause a decline in the coating performance of water-based paints, the present patent application has been developed. A copolymer obtained by carrying out a copolymerization reaction of a human oil/fat fatty acid modified (meth)acrylic monomer, a nitrogen-containing monomer, and an ethylenically unsaturated carboxylic acid (JP-A-5
9-227940).

However, although the aqueous pigment dispersion obtained using the above-mentioned dispersant has excellent pigment dispersibility during production, when the dispersion is stored for a long period of time, the pigments aggregate with each other and become partially or completely hard. The product becomes a casing, and even if it is redispersed using a stirrer, it is impossible to return it to its pre-storage condition, which causes defects such as spots and reduced gloss on the coating. there was.

The present inventor has discovered that a dispersant for an aqueous pigment dispersion can be obtained by combining a long-chain macromonomer component with strong hydrophobicity and a monomer component having a specific nitrogen-containing heterocycle with strong hydrophilicity. When a copolymer is used, the copolymer has easy dispersibility,
The present invention was completed based on the finding that the storage stability of aqueous pigment dispersions can be improved without impairing excellent properties such as compatibility and coating performance.

Thus, according to the present invention, in an aqueous pigment dispersion comprising a pigment, a dispersant, and an aqueous medium, the dispersant comprises (A) at least one vinyl polymer selected from acryloyloxy, methacryloyloxy, allyloxy, and aromatic vinyl. Macromonomer having a functional group at one end (hereinafter referred to simply as "macromonomer") 3 to 98 parts by weight (B) At least one selected from vinylpyrrolidones, vinylimidazoles, and vinylcarbazoles 2 to 97 parts by weight of a vinyl monomer having a nitrogen-containing heterocycle (C) 0 to 20 parts by weight of α,β-ethylenically unsaturated carboxylic acid and (D) α other than the above (A) to (C) An aqueous pigment dispersion is provided, which is an aqueous product of a copolymer obtained by copolymerizing 0 to 91 parts by weight of a β-ethylenically unsaturated monomer.

According to the present invention, the above copolymer has a structure in which a long chain component with strong hydrophobicity derived from a macromonomer is bonded in a separated form to a main chain containing a specific nitrogen heterocycle-containing monomer with strong hydrophilicity. When the pigment is dispersed in water using this material, the functional groups of the copolymer are adsorbed or chemically bonded to the pigment particles, and at the same time, the long chains separated from the main chain of the copolymer are The chain component is entangled with the long chain component of another copolymer and wraps around the pigment particles to form a highly hydrophobic layer, thereby making it possible to obtain a stable aqueous pigment dispersion. The aqueous pigment dispersion is.

2, the pigment and water are surrounded by a layer of barrier that is hydrophobic and itself has a component with excellent hydrolysis resistance, which prevents the intrusion of substances such as water and alkalis, and The barrier layer consists of components with large steric hindrance, which prevents the pigments from approaching each other, resulting in precipitation,
Shows excellent storage properties with no agglomeration. Further, the long chain component in the copolymer can be easily and reliably introduced by using the macromonomer component used in the present invention. Furthermore, since the dispersion has a low acid value, that is, a small amount of carboxyl groups, it is possible to obtain a colored coating film with excellent properties such as #aqueous properties.

Hereinafter, the dispersant used in the aqueous pigment dispersion of the present invention will be explained in more detail.

The macromonomer used in the dispersant of the present invention has a vinyl polymer as its main chain, and has a radically polymerizable unsaturated group such as acryloyloxy, methacryloyloxy, allyloxy, and styryl at one end of the main chain. It is something.

In addition, as the components constituting the above molecular chain, for example,
It is obtained by homopolymerizing or copolymerizing one or more monomers shown below.

(1) Esters of acrylic acid or methacrylic acid; for example, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate,
Hexyl acrylate, octyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate,
C1-Ls alkyl esters of acrylic acid or methacrylic acid such as propyl methacrylate, inpropyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate; acrylic acid or methacrylic acid such as allyl acrylate, allyl methacrylate, etc. 02~. Alkenyl ester: C2~ of acrylic acid or methacrylic acid such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, etc., Hydroxyalkyl ester: C3 of acrylic acid or methacrylic acid such as allyloxyethyl acrylate, allyloxymethacrylate, etc. ~l, alkenyloxyalkyl ester.

(2) Vinyl aromatic compounds: for example, styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene.

(3) Polyolefin compounds: for example, butadiene,
Isoprene, cloprene.

(4) Others: acrylonitrile, methacrylaterile, methyl isopropenyl ketone; vinyl acetate, beoba monomer (Shell Chemical V product), vinyl propionate, vinyl pivalate, etc.

Among the above-mentioned monomers, it is preferable to use acrylic acid, methacrylic acid ester, vinyl aromatic compound, etc. from the viewpoint of polymerization rate, copolymerizability, etc.

The macromonomer used in the present invention can be prepared according to a conventionally known method. For example, the above monomer is mixed with a chain transfer agent having a carboxyl group such as thioglycolic acid, , a prepolymer having a carboxyl group at one end obtained by polymerization reaction in the presence of a polymerization initiator such as benzoyl peroxide, or an azo-based polymer having a carboxyl group such as azobiscyanovaleric acid by combining the above monomers. A prepolymer having a carboxyl group at one end obtained by a polymerization reaction in the presence of a polymerization initiator and a tertiary amine is reacted with a vinyl monomer having a functional group capable of reacting with the carboxyl group of the prepolymer. This can be done by The above vinyl monomers are typically, for example, glycidyl acrylate, glycidyl methacrylate, 2-
Monomers containing acryloyloxy or methacryloyloxy groups such as hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate: Containing 7lyloxy groups such as allyl alcohol and allyl glycidyl ether Examples include monomers and monomers containing aromatic vinyl groups such as p-isopropenylphenylglycidyl ether and p-vinylphenylglycidyl ether.

The molecular weight of the macromonomer used in the present invention is in the range of number average molecular weight 600 to 15,000, preferably 1,000.
If the molecular weight is less than 600, the storage stability of the aqueous pigment dispersion is poor, while if the molecular weight is greater than 15,000, the storage stability of the main chain and side chain is The molecular weight is unbalanced, and the pigment dispersibility and storage stability of the aqueous pigment solution containing 1 part are poor.

Further, as the above-mentioned macromonomer, for example, Aron macromonomer M M 5 A S (Toa Go I&
Co., Ltd., product name, polystyrene-acrylonitrile type)
, Aron macromonomer MM-5M (manufactured by the same company, polymethyl methacrylate type), Aron macromonomer MM-
5B (manufactured by the same company, poly n-butyl acrylate type), and the like.

Vinyl intermediater having a nitrogen-containing heterocycle used in the present invention (
B) is a monomer in which a monocyclic or polycyclic heterocycle containing one or two ring nitrogen atoms selected from vinylpyrrolidones, vinylimidazoles, and vinylcarbazoles is bonded to a vinyl group, such as , and the monomers shown below.

(1) Vinylpyrrolidones; For example, 1-vinyl-2-pyrrolidone, l-vinyl-3
- such as pyrrolidone.

(11) Vinylimidazoles; For example, 1-vinylimidazole, 1-vinyl-2-methylimidazole, etc.

010 Vinyl carbazoles; For example, N-vinylcarbazole.

Among the above-mentioned monomers, vinylpyrrolidones in particular have strong hydrophilic properties, so a small amount can make highly hydrophobic components such as macromonomers hydrophilic, and form an aqueous dispersion with a well-balanced balance between wood-philicity and hydrophobicity. Therefore, he is right-handed.

The α,β-ethylenically unsaturated carboxylic acid (C) used in the present invention is an unsaturated type having an addition-polymerizable double bond between a carbon atom to which a carboxyl group is bonded and a carbon atom adjacent thereto. Aliphatic or polycarboxylic acids containing 3 to 8, especially 3 to 5 carbon atoms and having 1 or 2 carboxyl groups are suitable, for example acrylic acid, methacrylic acid, crotonic acid. , itaconic acid, maleic acid, maleic anhydride, fumaru, etc.

In addition to the i-mers (A) to (C) above, α.

The β-ethylenically unsaturated monomer (D) can be selected from a wide range depending on the performance desired for the aqueous coating composition of the present invention. Acrylic or methacrylic acid esters, alkenyl esters, hydroxyalkyl esters, alkenyloxyalkyl esters, vinyl aromatic compounds, polyolefin compounds, acrylonitrile, methacrylonitrile, methyl isopropenyl ketone, vinyl acetate,
Examples include monomers such as beoba monomer, vinyl propionate, and vinyl pivalate.

Among these monomers, esters of acrylic acid or methacrylic acid and vinyl aromatic compounds are particularly suitable.

These unsaturated monomers are appropriately selected depending on the desired physical properties, and may be used alone or in combination of two or more.

According to the present invention, the macromonomer (A), the vinyl monomer (B) having a nitrogen-containing heterocycle, the α,β-ethylenically unsustainable carboxylic acid (C) and the unsaturated monomer (D ) are copolymerized with each other. The copolymerization can be carried out according to methods known per se for producing acrylic copolymers, such as solution polymerization, emulsion polymerization, suspension polymerization, and the like.

The blending ratio of the above four components in copolymerization can be changed depending on the desired performance as a dispersant, but it is appropriate to mix them in the following ratios.

Macromonomer (A): 3 to 98 parts by weight, preferably 10 to 85 parts by weight in terms of pigment dispersibility and storage stability, Vinyl monomer (B) having a nitrogen-containing heterocycle: 2 to 97 parts by weight, preferably is from 3 to 3 in terms of pigment dispersibility and storage stability.
90 parts by weight, α, β-ethylenically unsaturated carbon II (C): 0 to 2
0 parts by weight, preferably 2 to 1 in terms of water solubility and coating performance
8 parts by weight, unsaturated monomers (D) other than the above (A) to (C) 20 to 9
1 part by weight, preferably 5 to 83 parts by weight from the viewpoint of coating film performance.

The above copolymerization reaction is preferably carried out according to a solution polymerization method, in which the above four components are mixed in a suitable inert solvent in the presence of a polymerization catalyst, usually at about 0 to about 180°C, preferably at about At a reaction temperature of 40 to about 170°C, about 1 to
This can be carried out by continuing the reaction for about 20 hours, preferably about 6 to about 10 hours.

As the solvent used, it is desirable to use a solvent that can dissolve the copolymer to be produced and is miscible with water so that gelation does not occur during the copolymerization reaction, especially when obtaining an aqueous pigment dispersion. It is best to use it as is without removing it.

Such solvents include, for example, those with the formula HO-CH2CH20R
I [However, R1 is a hydrogen atom or a carbon atom number of 1 to
8 alkyl groups] such as ethylene glycol, butyl cellosolve, ethyl cellosolve, etc.;
1 has the same meaning as cloudy CH3 above], such as propylene glycol 7-methyl ether;
Formula HO-CH2C)12-OCH2C)(2-OR,
Carpitol solvents [wherein R1 has the same meaning as above] such as diethylene glycol, methylcarpitol, butylcarpitol, etc.; formula R20-CH2
CH2-OR3 [wherein R2 and R3 each represent an alkyl group having 1 to 3 carbon atoms] glyme-based solvent such as ethylene glycol dimethyl ether; formula R2O-CH2CH20CH2-CH20R, [however, R2 and R3 are the same as above Diglyme solvents of the formula Ra OCH2CH20CO-CH3 [wherein R4 is a hydrogen atom or represents CH3 or C2H5] such as diglyme solvents such as diethylene glycol dimethyl ether; cellosolve acetate solvents of the formula Ra OCH2CH20CO-CH3 [wherein R4 represents a hydrogen atom or CH3 or C2H5] such as ethylene glycol monoacetate, methylcerone rub acetate, etc.; Formula R3OH [where R6 has 1 to 4 carbon atoms]
alcoholic solvents such as ethanol, propatool, and the like; as well as diaseptone alcohol, dioxane, tetrahydrofuran, acetone, dimethylformamide, 3-methoxy-3-methyl-butanol, and the like can be used.

However, it is also possible to use inert solvents that are immiscible with water, and such water-immiscible solvents include those with a boiling point below 250°C so that they can be easily removed by distillation under normal or reduced pressure after the polymerization reaction is completed. Examples of such solvents include aromatic hydrocarbons such as toluene, xylene, etc. etc.; with the formula Rs -COO-Rw [wherein R3 represents an alkyl group having 1 to 6 carbon atoms, and R and o represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a cyclohexyl group]; Acids or esters such as acetic acid, ethyl formate, butyl acetate, cyclohexyl acetate, etc.; formula RuR, C=O [where R and R12 each represent an alkyl group having 1 to 8 carbon atoms, methyl ethyl ketone, Cyclohexanone etc.1
Formula Ru-0R, 2 [However, R and R12 have the same meanings as above, such as ethers represented by , such as ethyl ether, hexyl ether, etc.: Formula R, OH [However, Ru has 5 to 11 carbon atoms] [representing an alkyl group], such as hexanol.

These solvents contain 15 to 9 of the total weight of the four copolymer components.
It can be used in a range of 0% by weight.

Examples of polymerization catalysts include azo compounds, peroxide compounds, sulfides, sulfines, sulfinic acids, diazo compounds, nitroso compounds, redox compounds, and radical initiators that can be used in normal radical polymerization such as ionizing radiation. agent is used.

In the present invention, a substantially satisfactory aqueous pigment dispersion can be obtained even if the molecular weight of the copolymer to be produced changes, but if the molecular weight is too low, there is a risk of deterioration of the physical properties of the water-based paint to be colored. be.

In addition, if the molecular weight is too high, the viscosity will increase, and if the viscosity is lowered, the concentration of the copolymer will decrease and the dispersibility of the pigment will decrease.

The number average molecular weight of the copolymer produced is approximately 1, O'00
to about 150,000, preferably from about 1,500 to about
It is right-handed to do this until it is within the range of o, ooo.

The copolymer resin thus produced can be made water-soluble as it is or after distilling off the solvent. This water solubility can be achieved by a conventional method, for example, by neutralizing the carboxyl groups present in the copolymer resin with a conventionally known neutralizing agent. Examples of neutralizing agents that can be used include ammonia, amines, alkali metal hydroxides,
Examples include carbonates or heavy acid salts of alkali metals.

As the amine, primary, secondary or tertiary alkylamines; primary, secondary or tertiary alkanolamines; and cycloalkylamines can be used. Further, as the hydroxide of the alkali metal, potassium hydroxide, sodium hydroxide, etc. can be used; as the carbonate and heavy acid salt of the alkali metal, potassium carbonate, sodium carbonate, sodium bicarbonate, etc. can be used. -+sugar 4 days.

The neutralization treatment can be easily carried out by a conventional method by adding the neutralizing agent or an aqueous solution thereof to the copolymer resin or its solution obtained as described above. The amount of neutralizing agent used is
Generally, 0.1 to 2.0 to the carboxyl group in the resin.
equivalent, preferably 0.3 to 1.0 equivalent.

The water-solubilized polymer thus obtained is used as a dispersant in an aqueous pigment dispersion consisting of a pigment 1 dispersant and an aqueous medium.

The amount of the dispersant made of the water-solubilizing polymer used is as follows:
00 parts by weight, generally from about 1 to 500 parts by weight, preferably from about 1 to 300 parts by weight. When the upper limit of this range is exceeded, the balance between coloring power and viscosity of the aqueous pigment dispersion tends to become imbalanced, while when it is outside the lower limit, the dispersion stability of the pigment tends to decrease.

The aqueous medium used in the aqueous pigment dispersion of the present invention is:
Although it is essentially water, if necessary, for example, if the degree of hydrophilicity of the dispersant is low and sufficient pigment dispersion performance cannot be obtained, a wood-philic organic solvent can be used in combination. . As the wood-philic organic solvent, those used in the production of the polymer can be used alone or in combination.

Furthermore, the pigments used in the aqueous pigment dispersions of the present invention can be inorganic and organic pigments commonly used in pigment dispersions of this type, for example, as inorganic pigments,
(1) Chemical resistant systems (zinc white, titanium dioxide, red iron oxide, chromium oxide, cobalt blue, iron black, etc.); (2) Hydroxide systems (alumina white, yellow iron oxide, etc.); (3
) Sulfide, selenide type (zinc sulfide, vermilion, cadmium diro, cadmium red, etc.); (4) ferrocyanide type (prussian degree, etc.); (5) chromate type (yellow,
(zinc chromate, molybdenum red, etc.); (6)
Sulfate-based (precipitated barium sulfate, etc.); (7) Carbonate-based (precipitated calcium carbonate, etc.); (8) Sulfate-based (
Hydrous silicates, clay, ultramarine, etc.); (9) Phosphates (
(10) carbon-based (carbon black, etc.); (11) metal powder-based (aluminum powder, bronze powder, zinc powder, etc.); and organic pigments include (1) nitroso-based pigments; (Naphthol Green B, etc.); (2) Nitro pigment-based (Naphthol Yellow S, etc.); (3) Azo m, H-based (Lysol Red, Lake Red C, Fast Yellow, Naphthol Ret, Ret?); (4) Dyeing (5) Phthalocyanine M material type C Phthalocyanine Blue, Fast Sky Blue, etc.); (6) li! These include polycyclic pigments (perylene red, quinacridone red, dioxazine high olent, indolinone yellow, etc.).

The content of the pigment in the aqueous pigment dispersion of the present invention is not particularly technically limited, but is generally about 2 to 90% by weight based on the weight of the dispersion.

The aqueous pigment dispersion of the present invention can be prepared by mixing together the above-mentioned components in a suitable dispersion device, such as a ball mill commonly used in the paint industry. , roll mill,
Examples include homomixers, sand grinders, shakers, and attritors.

If necessary, conventionally known surfactants and protective colloids can be added to the aqueous pigment dispersion of the present invention.

Therefore, the aqueous pigment dispersion of the present invention can be applied to alkyd resins, acrylic resins, etc. used in water-based paints and inks,
It has good miscibility with conventionally known water-soluble resins, water-dispersible resins, emulsions, etc. such as epoxy resins, urethane resins, maleated polybutadiene resins, etc., and is not limited by these resins, and can be made of any resin. It can also be widely used for coloring water-based paints.

As specific examples of the water-based resins mentioned above, for example, alkyd resins are synthesized from the same raw materials as conventional solvent-type alkyd resins, and are obtained by condensing polybasic acids, polyhydric alcohols, and oil components using conventional methods. be. Acrylic resin is α
, β-ethylenically unsaturated acids (e.g. acrylic acid, methacrylic acid, maleic acid, etc.), (meth)acrylic esters (e.g. ethyl acrylate, propyl acrylate,
It is obtained by copolymerizing vinyl aromatic compounds (such as styrene and vinyltoluene) and vinyl aromatic compounds (such as styrene and vinyltoluene). For epoxy resin, epoxy esters are synthesized by reacting the epoxy groups of epoxy resin with unsaturated fatty acids, and the unsaturated groups are subjected to α,β-unsaturation. Examples include epoxy ester resins obtained by esterifying polybasic acids such as mellitic acid.

In addition, the urethane resin is a resin formed by introducing a urethane group into the resin skeleton using a polyisocyanate compound (for example, toluene diisocyanate, diphenylmethane diisocyanate, 1,6-hexane diisocyanate, inphorone diisocyanate, etc.), and A carboxyl group is introduced using methylolpropionic acid or the like.

When using the above-mentioned aqueous resin as water-soluble, it is synthesized so that the acid value of the resin is about 35 to 200, and this is neutralized with an alkaline substance such as sodium aqueous solution or amine to make it water-soluble. Subjected to color paint. On the other hand, when these resins are used in a self-dispersion type, the acid value of the resin is made into a low-severity type resin of about 5 to 35, which is neutralized and used as a water-dispersed paint.

In addition, emulsions include emulsifier-dispersed emulsions obtained by dispersing alkyd resins, acrylic resins, epoxy resins, and urethane resins using anionic or nonionic low-molecular-weight surfactants; Emulsion polymerization emulsion obtained by emulsion polymerization of monomers such as acrylic acid ester, acrylonitrile, styrene, butadiene 5-acetate, vinyl chloride, etc.; maleated polybutadiene, maleated alkyd resin, maleated fatty acid modified vinyl resin, drying oil Alternatively, there may be mentioned a soap-free emulsion obtained by emulsion polymerization and graft reaction of the above-mentioned @mer by using a water-soluble resin such as a semi-drying oil-fatty acid modified acrylic resin as an emulsion stabilizer.

The aqueous pigment dispersion of the present invention is particularly effective when blended into water-based paints consisting of low acid value water-dispersible resins and emulsions, which have poor pigment dispersibility.

Among these, the effect is particularly remarkable for low acid value water-dispersible resins and emulsions that have oxidative curability.

The blending ratio of the aqueous pigment dispersion of the present invention to the aqueous paint can vary within a wide range depending on the type of pigment in the dispersion and the degree of coloring required for the paint.
Generally, per 100 parts by weight of the resin content of the water-based paint mentioned above,
The pigment dispersion liquid can be blended in a range of 2 to 1,000 parts by weight.

Next, the present invention will be further explained by examples.

In the examples, parts and % indicate parts by weight and % by weight.

Example 1 350 parts of n-butyl cellosolve was placed in a reaction vessel and heated to 120°C. Next, mix the mixture in the proportions shown below.
It was added dropwise to this solution over about 2 hours. The reaction was carried out under nitrogen injection.

Aron macromonomer MM-5B 56 parts n-
Butyl methacrylate 57 parts N-vinylpyrrolidone 126 parts Acrylic acid
11 parts Azobisdimethylvaleronitrile 17.5 parts The reaction temperature was maintained at 120° C., and the above mixture was added dropwise while stirring the reaction solution. One hour after the completion of the dropwise addition, 2.5 parts of azobisisobutyronitrile was added to the reaction solution, and after another 2 hours, 2.5 parts of azobisisobutyronitrile was added to the reaction solution, and then 1 hour was added for 2 hours.
The reaction was carried out while maintaining the temperature at 20'C.

After completion of the reaction, the unreacted monomer and n-butyl cellosolve were distilled under reduced pressure to obtain a heating residue of 70.3% and a resin acid value of 35.4. A copolymer solution with Gardner viscosity (40% n-butyl cellosolve solution) P was obtained. Further, this copolymer was neutralized with triethylamine (1.0 equivalent neutralization), and water was added to obtain a dispersant (I) consisting of an aqueous solution with a heating residue of 40%.

Next, a mixture of 8.3 parts of this dispersant and 200 parts of titanium white pigment (Titanium White R-5N manufactured by Sakai Chemical Co., Ltd.) was mixed with Red De
Dispersion was carried out for 0.5 hours using a MaII dispersing machine to obtain an aqueous pigment dispersion (A) of the present invention.

Pigments were similarly dispersed according to the formulations shown in Table 1 below to obtain aqueous pigment dispersions (B) to (D) of the present invention. In addition,
Pigments other than titanium white were dispersed for 1 hour.

The properties of the obtained aqueous pigment dispersion are summarized in Table 1 below.

Next, 10 parts of aqueous pigment dispersion (A) and water-dispersed alkyd resin (linseed oil fatty acid/pentaerythritol/benzoic acid/isophthalic acid/maleic anhydride = 903/705
Oil length 30 made from /1140/610/45 (parts)
and an alkyd resin having an acid value of 16 with triethylamine.
A water-based paint (1) was prepared by thoroughly mixing a formulation consisting of 23.4 parts of a 40% solids solution obtained by neutralizing 0 equivalents.

In the same manner, formulations consisting of pigment dispersions and water-based resins shown in Table 2 below were sufficiently mixed to obtain water-based paints (2) to (6). The coating film performance of the obtained water-based paint is summarized in the table below.
Shown in 2.

Example 2 300 parts of n-butyl cellosolve was placed in a reaction vessel and heated to 120°C. Next, mix the mixture in the proportions shown below.
It was added dropwise to this solution over about 2 hours. The reaction was carried out under nitrogen injection.

Aron macromonomer MM-5M 75 parts n-butyl methacrylate 39 parts N-vinylpyrrolidone 125 parts acrylic acid
11 parts Azobisdimethylvaleronitrile
188 parts The reaction temperature was maintained at 120° C., and the above mixture was added dropwise while stirring the reaction solution. One hour after the completion of the dropwise addition, 2.5 parts of ambisisobutyronitrile was added to the reaction vessel, and after another 2 hours, 2.5 parts of azobisisobutyronitrile was added to the reaction solution, which was then kept at 120°C for 2 hours. I just reacted.

After the reaction, the unreacted monomer and n-butyl cellosolve were distilled under reduced pressure, and the heating residue was 70.2%, the resin acid value was 36.6,
Gardner viscosity (40% n-butyl cellosolve solution) Q
A copolymer solution was obtained.

Furthermore, this copolymer was neutralized with triethylamine.
．． 0 equivalent neutralization) and water was added to obtain a dispersant (II) consisting of an aqueous solution with a heating residue of 40%.

Next, the pigments shown in Table 1 below were dispersed using the obtained dispersant (II) in the same manner as in Example 1 to obtain an aqueous pigment dispersion (E) of the present invention.

In addition, a water-based paint (7) was prepared by thoroughly mixing this pigment dispersion (E) and a water-based resin shown in Table 2 below.

The properties of the pigment dispersion (E) and the coating performance of the water-based paint (7) are shown in Tables 1 and 2 below, respectively.

Example 3 Aron macromonomer MM-5AS 85 parts N-
A monomer mixture of 150 parts of vinyl-2-pyrrolidone and 15 parts of acrylic resin was subjected to a polymerization reaction according to the method described in Example 1. Heating residue 70.4%, resin acid value 45.5, Gardner viscosity (
A copolymer solution of R (40% n-butyl cellosolve solution) was obtained.

This material was neutralized with triethylamine (1, neutralized by Oi amount) to obtain a dispersant (m) consisting of an aqueous solution with a heating residue of 40%.

Next, the pigments shown in Table 1 below were dispersed using the obtained dispersant (III) in the same manner as in Example 1 to obtain an aqueous pigment dispersion (F) of the present invention.

Further, this pigment dispersion (F) and the water-based resin shown in Table 2 below were sufficiently mixed to prepare a water-based paint (8).

The properties of the pigment dispersion (F) and the coating performance of the water-based paint (8) are shown in Tables 1 and 2 below, respectively.

Example 4 A polymerization reaction was carried out under the same conditions as in Example 3, except that the same amount of N-vinylcarbazole was used instead of N-vinyl-2-pyrrolidon, and the heating residue was 71.3
%, a resin acid value of 32.7, and a Gardner viscosity (40% n-butyl cellosolve solution) of N. A copolymer solution was obtained. Next, neutralize this with triethylamine.1. (O equivalent neutralization), dispersant (TV) consisting of an aqueous solution with a heating residue of 40%
I got it.

Next, the pigments shown in Table 1 below were dispersed using the obtained dispersant (IV) in the same manner as in Example 1 to obtain an aqueous pigment dispersion (G) of the present invention.

In addition, a water-based paint (9) was prepared by thoroughly mixing this pigment dispersion (G) and a water-based resin shown in Table 2 below.

The properties of the pigment dispersion (G) and the coating performance of the water-based paint (9) are shown in Tables 1 and 2 below, respectively.

Example 5 In Example 1, 1-vinylpyrrolidone was replaced with
The polymerization reaction was carried out under the same conditions as in Example 1 except that vinyl imidazole was used, and the heating residue was 70.7% and the resin acid value was 35.4. A copolymer solution with a Gardner viscosity (40% n-butyl cellosolve solution) of M was obtained. Next, neutralize with triethylamine (1.0 equivalent neutralization), heating residue 40%
A dispersant (V) consisting of an aqueous solution of was obtained.

Next, the pigments shown in Table 1 below were dispersed using the obtained dispersant (V) in the same manner as in Example 1 to obtain an aqueous pigment dispersion (H) of the present invention.

Further, this pigment dispersion (H) and the water-based resin shown in Table 2 below were sufficiently mixed to prepare a water-based paint (10).

The properties of the pigment dispersion (H) and the coating performance of the water-based paint (10) are shown in Tables 1 and 2 below, respectively.

Comparative Example 1 Safflower oil fatty acid (236 parts), glycidyl methacrylate (119 parts), hydroquinone (0.4 parts), and tetraethylammonium (0.2 parts) were placed in a reaction vessel and heated at a temperature of 140 to 150°C. Addition reaction was carried out for 4 hours,
A fatty acid modified monomer was obtained. Next, instead of the aron macromonomer MM-5B of Example 1, the above fatty acid-modified intermediate was used to perform a polymerization reaction, and the heating residue was -70.1%, the resin acid value was 35.2, and the cardner viscosity was (40% n-butyl cellosolve solution) A copolymer solution of L was obtained. Next, neutralize with triethylamine (1.0 equivalent neutralization), heating residue 4
A dispersant U) consisting of a 0% aqueous solution was obtained.

Next, the pigments shown in Table 1 below were dispersed using the obtained dispersant (VI) in the same manner as in Example 1 to obtain an aqueous pigment dispersion (D).

In addition, a water-based paint (11) was prepared by sufficiently mixing this pigment dispersion (I) and a water-based resin shown in Table 2 below. The properties of the pigment dispersion (I) and the coating film performance of the water-based paint (11) are shown in Tables 1 and 2 below, respectively.

Yo1 Titanium White R-5N: Titanium Oxide Carbon MA manufactured by Sakai Chemical Co., Ltd.: Carpon Black Mabico Yellow XLO manufactured by Mitsubishi Kasei Co., Ltd. Yellow pigment 42 manufactured by Titanium Industries Co., Ltd. Measured according to ASTM D1201-54.3
The acid value of the water-dispersed alkyd resin used in Example 1 was 60.
An emulsion (solid content 40%) obtained by polymerizing 70 parts of n-butyl acrylate using 30 parts of a neutralized product of the resulting resin as an emulsion stabilizer. Methyl methacrylate/n-butyl methacrylate = 35. An emulsion obtained by polymerizing a monomer mixture consisting of /15150 (solid content 50%) [Coating film performance test] Water-based paints (1) to (11) were coated with a water-based dryer (trade name: "Dicknade" manufactured by Inu Nippon Ink Co., Ltd.) , Koba 1. Nihe 1
7. Now T'S'1OA) lykM口% IE Face-hearted
+r+n Drink+==)+ was added at a ratio of 1 part and painted on a mild steel plate. After drying for 3 days at 20°C and 75% relative humidity, it was used for testing.

Craftsmanship: Make 100 squares of 1mm width,
A test was carried out by pasting cellophane adhesive tape on it and peeling it off vigorously.

Water resistance: The condition of the coated surface was visually examined by immersing it in tap water at 20°C for 2 days.

Claims (1)

[Scope of Claims] In an aqueous pigment dispersion comprising a pigment, a dispersant, and an aqueous medium, the dispersant comprises (A) at least one vinyl polymerizable functional group selected from acryloyloxy, methacryloyloxy, allyloxy, and aromatic vinyl. 3 to 98 parts by weight of a macromonomer having a group at one end (B) 2 to 97 parts by weight of a vinyl monomer having at least one nitrogen-containing heterocycle selected from vinylpyrrolidones, vinylimidazoles, and vinylcarbazoles ( C) Copolymerization of 0 to 20 parts by weight of an α,β-ethylenically unsaturated carboxylic acid and (D) 0 to 91 parts by weight of an α,β-ethylenically unsaturated monomer other than (A) to (C) above. An aqueous pigment dispersion, characterized in that it is an aqueous product of a copolymer obtained by.