JP2002069144A - Copolymer with excellent pigment dispersibility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide excellent dispersibility and dispersion stability of a wide range of pigments, especially excellent dispersibility and dispersion stability of hardly dispersible pigments such as diketopyrrolopyrrole pigments, and the original coloration of the pigment. To provide a pigment dispersion capable of showing the following. SOLUTION: The present invention provides (a) 5 to 50 parts by weight of a carboxyl group-containing polymerizable unsaturated macromonomer, and (b) at least one polymerizable polymer selected from a polyalkyl (meth) acrylate macromonomer and a polystyrene macromonomer. It is obtained by copolymerizing 30 to 70 parts by weight of an unsaturated macromonomer and 5 to 65 parts by weight of (c) another polymerizable unsaturated monomer copolymerizable with the component (a) and / or (b). Has a number average molecular weight of 2,
A copolymer having a resin acid value in a range of 000 to 100,000 and a resin acid value in a range of 10 to 200 mgKOH / g;
An object of the present invention is to provide a pigment dispersion using the copolymer and a coating composition using the pigment dispersion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copolymer excellent in pigment dispersibility, especially of an organic pigment such as diketopyrrolopyrrole, a pigment dispersion using the copolymer, and a pigment dispersion. The present invention relates to a coating composition having excellent color development stability.

[0002]

2. Description of the Related Art Conventionally, paste-like pigment dispersions in which a pigment is dispersed in a mixture of a dispersing resin, a solvent and, in some cases, a dispersing aid have been widely used in paints and inks for coloring. . In the field of paints and inks, social demands have increasingly required not only the performance of coating films and printed materials themselves, but also the improvement of characteristics such as coloring and sharpness. To meet this requirement, various organic pigments such as phthalocyanine pigments, quinacridone pigments, and diketopyrrolopyrrole pigments have been developed.

[0003] However, even if a pigment having excellent coloring properties and sharpness required by society has been developed, a dispersion suitable for the pigment must be obtained in order to obtain a dispersion exhibiting the original color of the pigment. Resins and dispersing aids must be used. Further, the pigment dispersion must have sufficient stability so that the pigment particles do not re-aggregate when used in paints and inks. Therefore, conventionally, the dispersing resin and the dispersing aid have an excellent pigment dispersing ability capable of maximizing the coloring properties of the available pigments, and only prevent the pigment particles in the formed pigment dispersion from reaggregating. Dispersion resins and / or dispersing aids having excellent pigment dispersion stability are being developed.

[0004] For example, (1) a method of using a lubricant such as a nonionic, cationic or anionic surfactant as a dispersing aid (GB 1108261, GB 11592)
52), (2) a method of using a derivative of a pigment as a dispersing aid, mixing it with the pigment, and dispersing the pigment (see JP-A-51-18736), and (3) a dispersing aid. A method of using a nitrogen-containing compound and a polyester oligomer as a dispersing resin to improve the dispersing ability of the pigment and the stability of the pigment dispersion by utilizing the affinity between the polyester oligomer and the nitrogen-containing compound (Japanese Patent Application Laid-Open No. (See JP-A-58-145762) and (4) a method using a pigment adsorbing component having a nitrogen-containing substituent and a pigment dispersant comprising a component forming a steric repulsion layer composed of a polyester resin (see JP-A-4-352882). , (5) a monomer having a tertiary amino group and / or a quaternary ammonium base and a polyalkyl (meth) acryle having a (meth) acryloyl group at a terminal A method of using a copolymer obtained from preparative macromonomer (see Japanese Patent Laid-Open No. 8-253540) have been proposed.

However, in the dispersion aid used in the above method (1), the adsorption layer adsorbed on the particle surface is thin,
No sufficient stabilizing effect is exhibited, no improvement in pigment dispersibility is observed, and in the above method (2), since the pigment derivative used is essentially colored, this method is applied to various pigments. It cannot be used for general purposes. In the above method (3), the polyester oligomer used has poor compatibility with an acrylic resin, which is particularly important as a coating resin, and it is difficult to obtain the original coloration of the pigment in an acrylic resin-based coating. Furthermore, in the above methods (4) and (5), a steric repulsion component is introduced, but this is not sufficient in terms of adsorption to the pigment, and the dispersion stability of the pigment is not sufficient. In particular, in the dispersion of a diketopyrrolopyrrole-based pigment, the coloring property and dispersion stability are extremely poor because the adsorption to the pigment is not sufficient. In order to improve this, surface treatment has been attempted on the pigment surface, but even if the surface treatment is performed, the dispersion stability of the pigment does not improve so much, and the pigment itself cannot sufficiently draw out its original color developing properties. Alternatively, when the pigment concentration becomes high, a problem occurs due to the surface treatment agent of the pigment.

Thus, the main object of the present invention is to provide excellent dispersibility and dispersion stability of a wide range of pigments, especially excellent dispersibility and dispersion stability of hardly dispersible pigments such as diketopyrrolopyrrole pigments. A pigment dispersion capable of exhibiting color development, a dispersion resin useful for producing such a pigment dispersion, and a color composition using the pigment dispersion, a coating composition having excellent coating film appearance. To provide.

[0007]

According to the present invention, there are provided (a) a carboxyl group-containing polymerizable unsaturated macromonomer 5 to 50;
Parts by weight, (b) at least one polymerizable unsaturated macromonomer selected from polyalkyl (meth) acrylate macromonomer and polystyrene macromonomer 3
A number average molecular weight obtained by copolymerizing 0 to 70 parts by weight and (c) 5 to 65 parts by weight of another polymerizable unsaturated monomer copolymerizable with the component (a) and / or (b). Is in the range of 2,000 to 100,000 and the acid value of the resin is in the range of 10 to 200 mgKOH / g.

The present invention also provides a pigment dispersion containing the above copolymer, pigment, organic solvent and, if necessary, a dispersing aid.

The present invention further provides a coating composition containing the above pigment dispersion.

Hereinafter, the present invention will be described in more detail.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The copolymer of the present invention copolymerizes a carboxyl group-containing macromonomer (a), a specific macromonomer (b) and another polymerizable unsaturated monomer (c) described below. It is obtained by this.

Carboxyl group-containing polymerizable unsaturated macromo
Nomer (a) : The carboxyl group-containing polymerizable unsaturated macromonomer which is the component (a) constituting the copolymer of the present invention has at least one carboxyl group and one polymerizable unsaturated bond in one molecule. And a monomer component useful for effectively adsorbing the pigment when the copolymer of the present invention is used for pigment dispersion. Since the component (a) is in the form of a macromonomer, in the copolymer of the present invention,
The pigment adsorbing component can be more localized, and by this localization, the adsorbing power of the copolymer of the present invention to the pigment can be improved, and reaggregation of the pigment can be prevented. Dispersion stability can be improved.

The carboxyl group-containing polymerizable unsaturated macromonomer (a) can be produced by a production method known per se. For example, a vinyl polymer having a carboxyl precursor group which can be converted into a carboxyl group by post-treatment is synthesized in advance. The vinyl polymer can be produced by introducing a polymerizable unsaturated group into the vinyl polymer and converting the carboxyl precursor group into a carboxyl group. More specifically,
For example, a monomer mixture consisting of tert-butyl (meth) acrylate and another vinyl monomer is converted into an organic solvent using a carboxyl group-containing chain transfer agent represented by 3-mercaptopropionic acid and, if necessary, a radical polymerization initiator. Is carried out in the presence of to obtain a copolymer having a terminal carboxyl group. Next, an epoxy group-containing monomer such as glycidyl methacrylate is reacted with the copolymer, and a carboxyl group and an epoxy group are reacted to introduce a polymerizable double bond into a terminal of the copolymer. Then, an acid catalyst such as p-toluenesulfonic acid is added to the copolymer into which the polymerizable double bond is introduced, and the copolymer is heated to obtain tert-
By decomposing the -butyl ester group and converting it into a carboxyl group, a carboxyl group-containing macromonomer having a polymerizable double bond at the molecular chain end can be produced.

In the present specification, "(meth) acrylate" means "acrylate" or "methacrylate".

The carboxyl group-containing polymerizable unsaturated macromonomer (a) is generally used in an amount of from 500 to 15,000, especially from 60, in view of localization of the pigment adsorbing group and easiness of production.
It is preferred to have a number average molecular weight in the range of 0 to 10,000. In addition, the carboxyl group-containing polymerizable unsaturated macromonomer (a) is improved in dispersibility by adsorption to a pigment, solubility of the macromonomer, water resistance, etc.
20-400 mgKOH / g, preferably 25-300
It is preferred to have an acid number in the range of mg KOH / g. Further, the carboxyl group-containing polymerizable unsaturated macromonomer (a) is preferably linear and can have a polymerizable double bond at at least one terminal, preferably at one terminal of its molecular chain.

Polymerizable unsaturated macromonomer (b) : The polymerizable unsaturated macromonomer which is the component (b) constituting the copolymer of the present invention is selected from polyalkyl (meth) acrylate macromonomer and polystyrene macromonomer. At least one macromonomer having a polymerizable unsaturated bond at one end or both ends of the molecular chain.

The polyalkyl (meth) acrylate macromonomer includes methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth) acrylate. Of acrylic acid or methacrylic acid such as meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, and stearyl (meth) acrylate. Alkyl esters,
Preferably, the main chain is a (co) polymer of acrylic acid or methacrylic acid having 1 to 24 carbon atoms in the alkyl group.

The polyalkyl (meth) acrylate macromonomer is prepared, for example, by subjecting one or a mixture of two or more alkyl esters of acrylic acid or methacrylic acid to a carboxyl group-containing chain transfer represented by 3-mercaptopropionic acid. Copolymerization is carried out in the presence of an organic solvent using an initiator and, if necessary, a radical polymerization initiator, to obtain a copolymer having a carboxyl group at a terminal, and then polymerizing the copolymer containing an epoxy group such as glycidyl methacrylate. It can be obtained by introducing a polymerizable double bond into the terminal of the copolymer by reacting the unsaturated monomer with a carboxyl group and an epoxy group.

The polystyrene macromonomer is prepared, for example, by copolymerizing styrene in the presence of an organic solvent using a carboxyl group-containing chain transfer agent represented by 3-mercaptopropionic acid and, if necessary, a radical polymerization initiator. Then, a copolymer having a carboxyl group at the terminal is obtained.Then, the copolymer is reacted with an epoxy group-containing polymerizable unsaturated monomer such as glycidyl methacrylate, and reacted with the carboxyl group and the epoxy group to form a copolymer terminal. It can be obtained by introducing a polymerizable double bond.

In the copolymer of the present invention, the polymerizable unsaturated macromonomer (b) forms a steric repulsion layer different from the carboxyl group-containing polymerizable unsaturated macromonomer (a) which is a pigment adsorbing component. It functions to prevent re-aggregation of the pigment. Thus, the macromonomer (b) is usually selected from the viewpoints of easy formation of the steric repulsion layer, stability of the pigment dispersion, and easy production of the macromonomer (b).
1,000-15,000, especially 1,200-10,0
It preferably has a number average molecular weight in the range of 00.

Such a macromonomer (b) is available as a commercial product, for example, “Macromonomer AA-6” manufactured by Toagosei Co., Ltd. (polymethyl methacrylate having a methacryloyl group at a polymer chain terminal, "Number average molecular weight about 6,000", "macromonomer AW-6" (polyisobutyl methacrylate having a methacryloyl group at the polymer chain terminal, number average molecular weight about 6,000), "macromonomer AB-6" (polymer chain terminal Polybutyl methacrylate having a methacryloyl group, a number average molecular weight of about 6,000), "macromonomer AS-6" (polystyrene having a methacryloyl group at a polymer chain terminal, a number average molecular weight of about 6,000) and the like.

Other polymerizable unsaturated monomer (c) : In the copolymer of the present invention, the other polymerizable unsaturated monomer (c) is a carboxyl group-containing macromonomer (a) which is a highly polar pigment-adsorbing component. And a polymerizable unsaturated monomer other than the macromonomer (b), which is a dispersion stabilizing component having a relatively low polarity, as long as it is copolymerizable with the macromonomer (a) and / or (b). There is no particular limitation on the type.

Other polymerizable unsaturated monomers (c) include, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate,
C2-C8 hydroxyalkyl esters of acrylic acid or methacrylic acid such as 3-hydroxypropyl (meth) acrylate and hydroxybutyl (meth) acrylate; polyether polyols such as polyethylene glycol, polypropylene glycol and polybutylene glycol and acrylic acid Or monoesters with a polymerizable unsaturated carboxylic acid such as methacrylic acid; hydroxyalkyl vinyl ethers, allyl alcohol, hydroxyalkyl esters of acrylic acid or methacrylic acid, (poly) alkylene glycol mono (meth) acrylates, and lactones (eg, ε -Caprolactone, δ-valerolactone); polyether polyols such as polyethylene glycol, polypropylene glycol, and polybutylene glycol. Monoether with a hydroxyl group-containing unsaturated monomer such as 2-hydroxyethyl (meth) acrylate; monoepoxy compounds such as α, β-unsaturated carboxylic acid and Cardura E10 (manufactured by Shell Chemical) or α-olefin epoxide Adduct with glycidyl (meth) acrylate and acetic acid, propionic acid, pt-
Adducts with monobasic acids such as butylbenzoic acid and fatty acids; hydroxyalkyl ethers such as hydroxyethyl vinyl ether; hydroxyl-containing unsaturated monomers such as allyl alcohol; ethyl (meth) acrylate, n-butyl (meth) acrylate Acrylic acid such as isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, and stearyl (meth) acrylate; C2-C24 alkyl esters of methacrylic acid; C2-C18 alkoxyalkyl esters of acrylic acid or methacrylic acid such as methoxyethyl (meth) acrylate and methoxybutyl (meth) acrylate; Vinyl ether, n- propyl vinyl ether, hexyl vinyl ether, cyclopentyl vinyl ether, cyclohexyl vinyl ether,
Vinyl ethers such as phenyl vinyl ether; allyl ethers such as allyl ethyl ether; vinyl esters such as vinyl acetate, vinyl butyrate, vinyl pivalate and veova monomer (manufactured by Shell Chemical); propenyl such as isopropenyl acetate and isopropenyl propionate; Esters; olefinic compounds such as ethylene, propylene, butylene; vinyl aromatic compounds such as styrene, α-methylstyrene, vinyltoluene; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,3- Butylene di (meth) acrylate, 1,4-butanediol di (meth) acrylate, glycerin di (meth) acrylate, glycerin tri (meth) acrylate, trimethylolpropane di (meth) acrylate, Trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth)
(Meth) acrylates of polyhydric alcohols such as acrylate, pentaerythritol tetra (meth) acrylate, neopentyl glycol di (meth) acrylate, and 1,6-hexanediol di (meth) acrylate; diallyl isophthalate, divinylbenzene And the like. These monomers can be used alone or in combination of two or more. Copolymer : The copolymer of the present invention comprises a carboxyl group-containing polymerizable unsaturated macromonomer (a) which is a component adsorbed on a pigment and a polymerizable unsaturated macromonomer which contributes to stabilization of dispersion, as described above. It can be obtained by copolymerizing b) and other polymerizable unsaturated monomers (c).
The copolymerization ratio of each of these components is 10
Based on 0 parts by weight, it can be within the following range.

Component (a): 5 to 50 parts by weight, preferably 10 to 45 parts by weight, more preferably 12 to 40 parts by weight. Component (b): 30 to 70 parts by weight, preferably 35 to 60 parts by weight.
Part by weight, more preferably 38 to 58 parts by weight Component (c): 5 to 65 parts by weight, preferably 5 to 55 parts by weight, more preferably 10 to 50 parts by weight.

The copolymerization of the above components (a), (b) and (c) is usually carried out in an organic solvent in the presence of components (a), (b) and (c).
About -20 ° C to about 160 ° C in the presence of about 0.01 to about 10 parts by weight of a polymerization initiator per 100 parts by weight of the total amount of the components.
At normal pressure or in some cases about 30
The reaction can be carried out under a pressure of up to kg / cm ² G. The organic solvent that can be used is not particularly limited as long as it can dissolve or disperse the components (a), (b), and (c) and the copolymer obtained by copolymerizing these components. Specifically, for example, aromatic solvents such as xylene and toluene; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl acetate, butyl acetate, isobutyl acetate and 3-methoxybutyl acetate Solvents: alcohol solvents such as n-butanol, isopropyl alcohol and the like can be mentioned.

As the above-mentioned polymerization initiator, a polymerization initiator known per se, which is used for polymerization of a polymerizable unsaturated monomer, can be used.
Azo-based polymerization initiators such as' -azobisisobutylnitrile, azobis-2-methylbutyronitrile, azobisdivaleronitrile; t-butylperoxyisobutyrate;
t-butylperoxy-2-ethylhexanoate, t
-Organic peroxide polymerization such as amyl peroxy 3,5,5-trimethylhexanoate, t-butylperoxyisopropyl carbonate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane Initiators and the like can be mentioned.

The copolymer thus obtained has a carboxyl group-containing macromonomer (a) unit which is a highly polar pigment adsorbing component and has a relatively low solubility parameter value (sp value). It is presumed that it has a well-balanced comb-shaped structure composed of the macromonomer (b) unit as a component and other polymerizable unsaturated monomer (c) units.

The copolymer of the present invention is generally used in an amount of 2,000 to 10 from the viewpoint of the dispersion stability of the pigment and the ease of handling.
It can have a number average molecular weight in the range of 000, preferably 3,000 to 50,000 and a resin acid number in the range of 10 to 200 mg KOH / g, preferably 15 to 150 mg KOH / g.

Pigment Dispersion The pigment dispersion of the present invention comprises the above-mentioned copolymer of the present invention as a pigment dispersing resin, a pigment, an organic solvent and, if necessary, a dispersing aid and, if necessary, other additives. contains.

Examples of the above-mentioned pigments include inorganic pigments such as titanium dioxide, zinc oxide, iron oxide, calcium carbonate, barium sulfate, graphite, clay, talc and carbon black; azo, diazo, condensed azo and thioindigo. System, indanthrone system, anthraquinone system, benzimidazolone system, phthalocyanine system, isoindolinone system,
Examples include various organic pigments such as perylene, quinacridone, dioxane, and diketopyrrolopyrrole. The copolymer of the present invention exhibits remarkable pigment dispersing ability and pigment dispersion stability as a pigment dispersing resin, especially for diketopyrrolopyrrole pigments.

The organic solvent can be used without any particular limitation as long as it can dissolve or disperse the copolymer. For example, the same organic solvents that can be used in the production of the copolymer can be used. Can be used.

Further, as a dispersing aid used as required, for example, a wetting agent and the like can be mentioned, and as other additives, for example, an antifoaming agent and the like can be mentioned.

The pigment dispersion of the present invention can be obtained by dispersing each of the above-mentioned raw material components by a method known per se. Examples of the disperser for obtaining the pigment dispersion of the present invention include a roll mill, a ball mill, a sand grind mill, a DCP mill, an LMZ mill, an attritor,
Paint shaker and the like can be mentioned.

In preparing the pigment dispersion, the amount of the copolymer of the present invention is not particularly limited, but is generally 5 to 300 parts by weight, especially 10 to 200 parts by weight, per 100 parts by weight of the pigment to be dispersed. It is convenient to use within the range of parts by weight. Coating composition: The pigment dispersion of the present invention comprises a binder resin for coating and, if necessary, an organic solvent, polymer fine particles, a curing catalyst, an ultraviolet absorber, an ultraviolet stabilizer, a coating surface regulator, an antioxidant, and a fluid. A coating composition can be obtained by mixing with additives such as a property adjusting agent and a silane coupling agent.

The above-mentioned binder resin for paint includes a base resin usually used for paint and a combination of the base resin and a curing agent. Examples of the base resin include a hydroxyl group-containing acrylic resin, a hydroxyl group-containing polyester resin and an epoxy resin. Resins, epoxy group-containing acrylic resin, carboxyl group-containing high acid value polyester resin, carboxyl group-containing high acid value acrylic resin, and the like.
One type or a combination of two or more types can be used. Examples of the curing agent include an amino resin and a polyisocyanate compound which may be blocked.

As the binder resin for coating, at least one base resin selected from a hydroxyl group-containing acrylic resin and a hydroxyl group-containing polyester resin, and at least one selected from an amino resin and a polyisocyanate compound which may be blocked. A combination with one curing agent; at least one resin selected from an epoxy resin and an epoxy group-containing acrylic resin, and at least one resin selected from a high acid value polyester resin and a high acid value acrylic resin
Combinations with different carboxyl group-containing resins can be suitably used.

As the organic solvent used as required, various organic solvents similar to those exemplified as the organic solvent that can be used in the production of the copolymer can be used.

The polymer fine particles are polymers which are not dissolved in the coating composition of the present invention and are dispersed as solid fine particles, and those known per se can be used.
Those having an average particle size in the range of 0.01 to 1 μm are preferred. The polymer particles may or may not be cross-linked inside the particles, but preferably are internally cross-linked.

When the curing agent is a polyisocyanate compound which may be blocked, examples of the curing catalyst include dibutyltin diacetate, dibutyltin dioctate, dibutyltin dilaurate, triethylamine, diethanolamine and the like. When the agent is an amino resin such as a melamine resin, examples thereof include sulfonic acid compounds such as paratoluenesulfonic acid, dodecylbenzenesulfonic acid, and dinonylnaphthalenesulfonic acid, and amine neutralized products of these sulfonic acid compounds. it can.

Examples of the ultraviolet absorber include benzophenone-based, benzotriazole-based, cyanoacrylate-based, salicylate-based, and oxalic anilide-based compounds. Examples of the ultraviolet stabilizer include a hindered amine-based compound Can be mentioned.

The coating composition of the present invention can be used in the field where a colored coating is used. For example, a top-coating color coating for one-coat top-coat finishing;
2 coats of top coat clear finish finish (2 coats 1
Colored base paint in bake finish, 2 coat 2 bake finishes included; 3 coat top coat finish (3 coats 1 bake finish, 3 coats 2 bake finishes, 3 coats 3 bake finishes included) It can be suitably used as a base paint or the like.

[0042]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. "Parts" and "%" in the examples are all based on weight.

Synthesis of Carboxyl Group-Containing Macromonomer Synthesis Example 1 Methoxypropyl acetate 1 was placed in a flask equipped with a stirrer, condenser, thermometer, nitrogen inlet tube and dropping device.
00 parts, 60 parts of methyl methacrylate and tert
2 parts of 2,2′-azobisisobutyronitrile (hereinafter may be abbreviated as “AIBN”) and 40 parts of 3-butyl methacrylate are dropped at a polymerization temperature of 100 ° C. under a nitrogen stream and 3-mercaptopropion. Radical polymerization was carried out using 7.7 parts of acid. To the obtained polymer solution having a terminal carboxyl group, 1 part of tetrabutylphosphonium bromide, 0.1 part of hydroquinone monomethyl ether and 8.8 parts of glycidyl methacrylate were added, and the mixture was heated at 90 ° C.
For 6 hours to introduce a polymerizable double bond at the terminal.
Next, 1 part of p-toluenesulfonic acid was added to this solution, and the mixture was heated at 120 ° C. for 5 hours to decompose the tert-butyl ester group, convert it into a carboxyl group, and obtain a solid content of 50%.
To obtain a carboxyl group-containing macromonomer solution (a-1). The resulting macromonomer has an acid value of 160 mgK
OH / g and the number average molecular weight in terms of styrene (“GP
C ", the number average molecular weight in terms of styrene by gel permeation chromatography, the same applies hereinafter) was 1,500.

Synthesis Example 2 The same operation as in Synthesis Example 1 was carried out except that the amount of methyl methacrylate was changed to 64 parts and the amount of tert-butyl methacrylate was changed to 60 parts. A 50% carboxyl group-containing macromonomer solution (a-2) was obtained. The obtained macromonomer had an acid value of 200 mgKOH / g and a number average molecular weight in terms of styrene of 1,300.

Preparation of Copolymer Example 1 A flask equipped with a stirrer, a condenser, a thermometer, a nitrogen inlet tube and a dropping device was charged with 84 parts of propylene glycol monomethyl ether and the carboxyl having a solid content of 50% obtained in Synthesis Example 1 A group-containing macromonomer solution (a-1) 32 parts (16 parts in solid content) and "AW-6S" (manufactured by Toagosei Co., Ltd., a solution of a macromonomer which is a polyisobutyl methacrylate containing a methacryloyl group at a terminal, The solid content is 50%, and the number average molecular weight of the macromonomer is about 6,000.
0) 100 parts (50 parts in solid content) were blended and the temperature was 10
The mixture was heated and maintained at 0 ° C., and a mixture of 24 parts of methyl methacrylate, 10 parts of styrene, and 1 part of AIBN was dropped therein over 4 hours under a nitrogen stream.
0.5 part of IBN was added, and the mixture was further reacted at the same temperature for 2 hours to obtain a copolymer solution (R-1) having a nonvolatile content of 40%, an acid value of 25 mgKOH / g, and a number average molecular weight of about 7,000.

Examples 2 to 7 The copolymer solution (R-2) was prepared in the same manner as in Example 1 except that the composition of the macromonomer and the monomer was changed to the composition shown in Table 1 below. ) To (R-7) were synthesized.

Comparative Example 1 100 parts of propylene glycol monomethyl ether and 100 parts of "AW-6S" (50 parts of solid content) were blended in a flask equipped with a stirrer, a condenser, a thermometer, a nitrogen inlet tube and a dropping device. Heat to 100 ° C, hold,
Under a stream of nitrogen, methyl methacrylate 30
, A mixture of 20 parts of styrene and 1 part of AIBN was added dropwise over 4 hours. After the addition was completed, 0.5 part of AIBN was further added, and the mixture was further reacted at the same temperature for 2 hours.
A resin solution (C-1) having a number average molecular weight of about 7,800 was obtained.

Comparative Example 2 In a flask equipped with a stirrer, a condenser, a thermometer, a nitrogen inlet tube and a dropping device, 134 parts of propylene glycol monomethyl ether and 50% of the solid content obtained in Synthesis Example 1 were added.
Carboxyl group-containing macromonomer solution (a-1) 3
2 parts (16 parts solids) and methyl methacrylate 3
4 parts, 50 parts of isobutyl methacrylate and AIBN1
Part of the mixture was added dropwise over 4 hours.
0.5 part of IBN was added, and the mixture was further reacted at the same temperature for 2 hours to obtain a resin solution (C-2) having a nonvolatile content of 40%, an acid value of 25 mgKOH / g, and a number average molecular weight of 5,500.

Comparative Example 3 A flask equipped with a stirrer, a condenser, a thermometer, a nitrogen inlet tube and a dropping device was charged with 100 parts of propylene glycol monomethyl ether and 100 parts of "AW-6S" (50 parts of solid content). Acid 4 parts, styrene 16
, A mixture of 30 parts of methyl methacrylate and 1 part of AIBN were added dropwise over 4 hours, and after the addition was completed, AIBN was further added.
0.5 part was added, and the mixture was further reacted at the same temperature for 2 hours to obtain a resin solution (C-3) having a nonvolatile content of 40%, an acid value of 26 mgKOH / g, and a number average molecular weight of about 8,400.

[0050]

[Table 1]

The notes in Table 1 above have the following meanings. (* 1) AA-6: manufactured by Toagosei Co., Ltd., a polymethyl methacrylate solution containing a methacryloyl group at a terminal, a solid content of about 45%, and a number average molecular weight of a macromonomer of about 6,000.
0.

Production of Pigment Dispersion Example 8 250 parts of the 40% copolymer solution (R-1) obtained in Example 1, 310 parts of propylene glycol monomethyl ether acetate, and "Rubin TR" (Ciba Geigy) as a pigment 80 parts of diketopyrrolopyrrole pigment (manufactured by K.K.) and 130 parts of glass beads were mixed, and the mixture was dispersed with a paint shaker for 4 hours to obtain a pigment dispersion (P-1).

Examples 9 to 16 and Comparative Examples 4 to 7 The same procedures as in Example 8 were carried out except that the copolymer solution, propylene glycol monomethyl ether acetate and pigment were mixed as shown in Table 2 below. By performing the operation, pigment dispersions (P-2) to (P-9) (Example) and pigment dispersions (P-10) to (P-13) (Comparative Example) were obtained.

With respect to the pigment dispersions obtained in Examples 8 to 16 and Comparative Examples 4 to 7, the viscosity, coating film gloss and transparency were measured according to the following test methods. Table 2 below shows the test results.
Shown in

Test Method Viscosity: The viscosity (mPa) of the pigment dispersion adjusted to a temperature of 20 ° C.
* S) was measured at a shear rate of IVO _s-1 using a viscoelasticity analyzer (manufactured by UBM).

Gloss of coating film: The pigment dispersion was applied on a PET film with a doctor blade (5 mil), and the gloss of the dried coating film was measured according to JIS K5400 7.6.

Transparency: The pigment dispersion was applied on a PET film with a doctor blade (5 mil) and dried. The transparency of the resulting coating film was measured using a turbidimeter (COH-300) according to the following formula. The light transmittance (%) was evaluated as follows.

Light transmittance (%) = 100 × [1- (scattered light intensity) / (irradiation light intensity)]

[0059]

[Table 2]

Production Example 1 of Resin for Paint Production Example 1 30 parts of Swazole 1000 (produced by Cosmo Oil Co., aromatic hydrocarbon solvent) and n-butyl were placed in an acrylic resin reaction tank equipped with a stirrer, thermometer, reflux condenser and the like. 5 parts of alcohol was charged, heated and stirred, and after the temperature reached 130 ° C., a mixture of the following monomers and the like was added dropwise over 3 hours.

Styrene 20 parts Methyl methacrylate 50 parts n-butyl acrylate 15 parts 2-hydroxyethyl methacrylate 15 parts 2,2′-azobisisobutyronitrile 5 parts n-butyl alcohol 5 parts The above monomers and the like After the addition of the mixture of
After maintaining at 30 ° C., an additional catalyst solution, which was a mixture of 0.5 part of 2,2′-azobisisobutyronitrile and 8 parts of swazole 1000, was added dropwise over 1 hour. One more
After stirring at 30 ° C. for 1 hour, the mixture was cooled. This was diluted with 8 parts of n-butyl alcohol to obtain an acrylic polymer solution (AP-1) having a solid content of 60%. The obtained acrylic polymer had a glass transition temperature of 60 ° C. and a hydroxyl value of 65 mgKOH / g.

Production Example 17 of Colored Paint Composition Example 80 of the pigment dispersion (P-1) obtained in Example 8, Production Example 1
92.5 parts (55.5 parts in solid content) of the acrylic polymer solution (AP-1) obtained in the above, Nikarac MS25 (manufactured by Sanwa Chemical Co., Ltd., trade name, butyl etherified melamine resin solution having a solid content of about 70%) 45.7 parts (solid content 3
2 parts), Nacure 5225 (Nacure 5225,
King Industries Co., USA, trade name, curing catalyst solution as amine neutralized solution of sulfonic acid compound, 2 parts of active ingredient 25%), and Disparon LC-955
(Kusumoto Kasei Co., Ltd., trade name, surface conditioner) (1 part) was mixed to obtain a colored coating composition.

Examples 18 to 25 and Comparative Examples 8 to 10 The same procedures as in Example 17 were carried out except that the composition was changed as shown in Table 3 below, and each colored coating composition was obtained.

Using the colored coating compositions obtained in Examples 17 to 25 and Comparative Examples 8 to 10, each test coated plate was prepared according to the following method for preparing test coated plates.

Method of preparing test coated plate Electrodeposited an epoxy resin-based cationic electrodeposition coating on a 0.8 mm thick cold-rolled dull steel plate which has been subjected to zinc phosphate chemical conversion treatment so that the dry film thickness is about 20 μm. On the baked electrodeposition coating film, a polyester resin intermediate coating for automobiles was applied so as to have a dry film thickness of about 20 μm and baked. This coated plate is water-dried with # 400 sandpaper, drained and dried,
Degreasing with petroleum benzine. Then, on the degreased plate, each of the above colored coating compositions was applied with a coating viscosity of 15 seconds (Ford Cup #
(25.degree. C.) at 25.degree. C.), using an air spray gun winder W71 (manufactured by Anest Iwata Co., Ltd.) so that the dry film thickness becomes about 35 .mu.m.
Each test coating was prepared by baking at 40 ° C. for 30 minutes.

Various tests were performed on these test coated plates based on the following test methods. The test results are shown in Table 3 below.
Shown in

Test Method Appearance of Coating Film: The finished appearance of the coating film was comprehensively investigated in terms of glossiness, smoothness, and solid feeling and evaluated according to the following criteria.

：: good, Δ: bad, ×: extremely poor.

Adhesion: JIS K-5400 8.5.
2 (1990) According to the crosscut-tape method, 11 parallel vertical and horizontal straight lines are drawn at 1 mm intervals on the surface of the coating film of the test plate so as to reach the substrate with a cutter knife, and the distance is 1 mm. 100 × 1 mm squares were created. A cellophane adhesive tape was adhered to the surface, and the degree of peeling of the squares when the tape was abruptly peeled was observed and evaluated according to the following criteria.

：: 90 or more squares of the coating film remained, Δ: the coating film was peeled, and the number of remaining squares was 50 or more and 90
Less than, ×: The coating film peeled off, and the number of remaining squares was less than 50.

Water resistance: 240 test pieces in a constant temperature bath at 40 ° C.
Soak for hours. After taking out, the coating film having no abnormality such as gloss or blister was evaluated as ○ (good), and the one having abnormality was evaluated as x (bad).

Impact resistance: JIS K-5400
According to 3.2 (1990) Dupont impact resistance test,
With the coating surface of the test coated plate facing upward, a test was conducted under the conditions of a drop weight of 500 g and a tip diameter of the hammer of about 12.7 mm, and evaluated according to the following criteria from the maximum drop weight height that would not damage the paint film did.

：: Maximum falling weight height of 50 cm or more, Δ: Maximum falling weight height of 30 cm or more and less than 50 cm, ×: Maximum falling weight height of less than 30 cm.

[0074]

[Table 3]

As described above, the copolymer of the present invention can be firmly adsorbed on the pigment surface by the component (a) constituting the copolymer, and the aggregation between the pigment particles can be cut off by the component (b). It is excellent in pigment dispersibility, and exhibits excellent pigment dispersibility even for pigments that are difficult to disperse, such as diketopyrrolopyrrole and diketopyrrolopyrrole derivatives.

Further, the pigment dispersion of the present invention prepared by using the copolymer of the present invention exhibits excellent coloring properties, can lower the viscosity of the pigment dispersion, and has excellent dispersion stability and storage stability. Excellent stability.

Further, the coatings produced using the pigment dispersion of the present invention show good coating appearance and can give coatings with good coating performance.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C09D 155/00 C09D 155/00 F term (reference) 4J027 AA02 AA08 AC03 AC04 AC06 AJ08 BA04 BA07 BA08 BA20 BA22 BA25 BA26 BA27 BA28 4J037 AA02 AA09 AA10 AA11 AA13 AA15 AA22 AA27 CC11 CC18 DD23 DD24 EE28 EE43 4J038 CR062 EA011 GA06 GA16 KA08 KA09 MA10 MA14 NA25 NA26

Claims (14)

[Claims] (1) 5 to 50 parts by weight of a carboxyl group-containing polymerizable unsaturated macromonomer, and (b) at least one polymerizable unsaturated macromolecule selected from a polyalkyl (meth) acrylate macromonomer and a polystyrene macromonomer. A number average obtained by copolymerizing 30 to 70 parts by weight of a monomer, and 5 to 65 parts by weight of (c) another polymerizable unsaturated monomer copolymerizable with the component (a) and / or (b). 2,000 molecular weight
１００100,000 and the resin acid value is 10１０〜
A copolymer characterized by being in the range of 200 mgKOH / g. 2. The method according to claim 1, wherein the macromonomer (a) is 500 to 15,
Number average molecular weight in the range of 000 and 20-400 mgK
2. The copolymer according to claim 1, having an acid value in the range of OH / g. 3. The macromonomer (a) is 600 to 10,
2. The copolymer according to claim 1, having a number average molecular weight in the range of 000. 4. The macromonomer (a) has a length of 25 to 300 m.
2. The copolymer according to claim 1, having an acid value in the range of gKOH / g. 5. The copolymer according to claim 1, wherein the macromonomer (a) has a polymerizable unsaturated bond at a molecular chain terminal. 6. When the macromonomer (b) is 1,000 to 1
The copolymer of claim 1 having a number average molecular weight in the range of 5,000. 7. The macromonomer (b) is 1,200 to 1,
The copolymer of claim 1 having a number average molecular weight in the range of 000. 8. A polymer obtained by copolymerizing 10 to 45 parts by weight of a macromonomer (a), 35 to 60 parts by weight of a macromonomer (b), and 5 to 55 parts by weight of another polymerizable unsaturated monomer. 2. The copolymer according to 1. 9. The copolymer according to claim 1, which has a number average molecular weight in the range of 3,000 to 50,000. 10. The copolymer according to claim 1, which has a resin acid value in the range of 15 to 150 mgKOH / g. 11. A pigment dispersion containing the copolymer according to claim 1, a pigment, an organic solvent and, if necessary, a dispersing aid. 12. The copolymer according to claim 1, which is a pigment 1
The pigment dispersion according to claim 11, which is contained in the range of 5 to 300 parts by weight per 00 parts by weight. 13. The pigment dispersion according to claim 11, wherein the pigment contains at least one pigment selected from diketopyrrolopyrrole and diketopyrrolopyrrole derivatives. 14. A coating composition containing the pigment dispersion according to claim 11.