JP2002069364A - Resin composition for coating material and coating method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an environment-friendly resin composition for coating material having high practicability, that is, capable of forming a coating film excellent in finished outer appearance, curability at a low temperature, weather resistance, water resistance, solvent resistance, impact resistance and the like even on a plastic material, and to provide a coating method using the composition. SOLUTION: The resin composition for coating material comprising a nonaqueous dispersion-type copolymer (C) and a blocked isocyanate (D) which is blocked by an active methylene-type blocking agent. In the composition, the nonaqueous dispersion- type copolymer (C) consists of the following: a copolymer (A) obtained by copolymerizing a polymerizable monomer having an unsaturated double bond, having a weightaverage molecular weight of 10,000-200,000 and a glass transition temperature of -40 to 20 deg.C, and soluble in an organic solvent; and dispersed particles (B) obtained by copolymerizing a polymerizable monomer having an unsaturated double bond in the presence of an organic solvent and insoluble in the organic solvent in the copolymer (A). The compounding ratio of (B) to the total solid components of (A) and (B) is 25-65 wt.%. And, a coating method using the composition is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating resin composition particularly suitable for plastic materials such as automobiles and a coating method using the same.

[0002]

2. Description of the Related Art In recent years, in the field of automobiles and the like, from the viewpoint of weight reduction, cost reduction, recycling, improvement of design, energy saving, and the like, plastic materials are being changed from thermosetting plastics to thermoplastics. is there. The coating on such a plastic material is limited in the heat deformation temperature of the plastic material, and a two-pack type paint using polyisocyanate as a curing agent is usually used. The problem here is that the two-pack type paint consists of two components, a polyol and a polyisocyanate, so it is necessary to store them separately and mix them at the time of painting. Also, once mixed, the use time of the paint is limited, which is a factor that significantly reduces workability. In order to remedy the above disadvantages, it has been proposed to use a blocked isocyanate in which all active isocyanate groups are blocked. In JP-A-4-246483, an oxime-based blocked isocyanate is disclosed in JP-A-5-86164.
In the publication, pyrazole or imidazole derivative-based blocked isocyanates are studied. When these blocked isocyanates are used, the above disadvantages can be improved, but when baking a paint, a high baking temperature of 120 ° C. or more is required, and it is difficult to apply a plastic material to form a coating film. In recent years, from the viewpoint of environmental issues, it has been required to reduce the amount of an organic solvent necessary for dissolving the resin, and for that purpose, it is necessary to achieve high solid differentiation of the resin solution. In order to achieve high solid differentiation of the resin solution, it is necessary to lower the viscosity of the resin, and a method such as reducing the molecular weight of the resin is employed as a means thereof, but it causes a decrease in curability and coating film performance. . Also, Japanese Patent Laid-Open No. 6-5
JP-A-7013 and JP-A-7-31953 describe compositions for one-pack coatings using active methylene-based blocked isocyanates. Although these one-pack coating compositions can also improve the use time of the coating, the finished appearance, low-temperature curability, solvent resistance, high solid differentiation, etc. are insufficient, so that the high durability required in recent years is required. It is poor in practicality as a base coat with low water, low pollution and resource saving.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned drawbacks and provides a coating film having excellent finish appearance, low-temperature curability, weatherability, water resistance and solvent resistance even for plastic materials. The present invention provides a highly practical resin composition for a high solid coating which can form a coating, and a coating method for forming a coating film using the resin composition for a coating.

[0004]

According to the present invention, there is provided (1) a polymer having a weight average molecular weight of 10,000 to 200,000 obtained by copolymerizing a polymerizable monomer having an unsaturated double bond and a glass transition temperature of Is obtained by copolymerizing a polymerizable monomer having an unsaturated double bond in the presence of a copolymer (A) soluble in an organic solvent at −40 to 20 ° C. and an organic solvent. A non-aqueous dispersion polymer (C) containing a copolymer particle (B) insoluble in an organic solvent in (A), wherein the mixing ratio of (B) is the total solid content of (A) and (B). 25-65% by weight
A coating resin composition comprising a non-aqueous dispersion type polymer (C) and a blocked isocyanate (D) blocked with an active methylene-based blocking agent, (2) the organic solvent is an aromatic solvent or an aliphatic solvent A solvent, a ketone-based solvent and an ester-based solvent, wherein the resin composition for a coating is at least one selected from the group consisting of: a solvent; a ketone-based solvent; and an ester-based solvent.
Has a hydroxyl value of 1 to 150 mgKOH / g and an acid value of 1 to 6
(4) The above resin composition for paint, which is 0 mgKOH / g.
The mixing ratio of the non-aqueous dispersion type polymer (C) and the blocked isocyanate (D) is 99/1 by weight ratio of (C) / (D).
５０50/50, and (5) the coating resin composition, 2 coats 1 bake finish, 2 coats 2 bake finishes, 3 coats 1 bake finish, 3 coats 2 bake finishes, 3 coats The present invention relates to a coating method used as a base coat having a 3 bake finish or a 1 bake finish.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The polymerizable monomer having an unsaturated double bond used in the polymerization of the copolymer (A) soluble in an organic solvent in the present invention may be any polymerizable monomer. For example, the polymerizable monomer (a1) having a carbon-carbon double bond, having neither a hydroxyl group nor a carboxyl group, and having an unsaturated double bond, is not particularly limited. A polymerizable monomer (a2) having a group and an unsaturated double bond, a polymerizable monomer (a3) having a carboxyl group and an unsaturated double bond, and the like are used. Examples of the monomer (a1) having neither a hydroxyl group nor a carboxyl group and having an unsaturated double bond include, for example,
Alkyl groups such as methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, etc. have 1 carbon atom.
Alkyl acrylates having from 20 to 20; cycloalkyl acrylates having 3 to 20 carbon atoms such as cyclohexyl acrylate; tricyclodecyl acrylate, tricyclodecyloxyethyl acrylate;
Tricycloalkyl acrylates having 5 to 20 carbon atoms such as tricyclodecyloxypropyl acrylate: methyl methacrylate, ethyl methacrylate, ethyl methacrylate, butyl methacrylate,
Alkyl methacrylate having 1 to 20 carbon atoms such as isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, and lauryl methacrylate: having 3 to 3 carbon atoms in a cycloalkyl group such as cyclohexyl methacrylate 20 cycloalkyl methacrylate; tricyclodecyl methacrylate, tricyclodecyloxyethyl methacrylate, tricyclodecyloxypropyl methacrylate and the like having 5 to 20 carbon atoms in the tricycloalkyl group; Aminoalkyl methacrylates having 1 to 20 carbon atoms in the alkyl group such as aminomethyl methacrylate and N, N-dimethylaminoethyl methacrylate; styrene, vinyltoluene, α-methylstyrene, t-butylstyrene and the like; Rene monomers; vinyl derivatives such as vinyl chloride, vinylidene chloride, vinyl acetate, isopropenyl acetate, glycidyl acrylate, glycidyl methacrylate, acrylamide, and methacrylamide; unsaturated dimethyl esters such as dimethyl ester maleate and diethyl ester maleate Examples thereof include a dialkyl ester of a basic acid, an acrylate or methacrylate having a hindered amino group, an acrylate or methacrylate having a benzotriazole group, acrylonitrile, and methacrylonitrile. The above components are
Used alone or in combination of two or more.

Among the above-mentioned polymerizable monomers, alkyl acrylate, cycloalkyl acrylate, tricycloalkyl acrylate, methacryl, etc. are preferred in view of the finished appearance, weather resistance, workability and other properties of the coating film. It is preferable to use at least one or more polymerizable monomers selected from acid alkyl esters, cycloalkyl methacrylates, and tricycloalkyl methacrylates. The amount of these polymerizable monomers used is 70 to 10 in the polymerizable monomer mixture containing an unsaturated double bond.
The content is preferably 0% by weight, more preferably 80 to 95% by weight.

The polymerizable monomer (a2) having a hydroxyl group and an unsaturated double bond used in the component (A) in the present invention includes, for example, hydroxyalkyl acrylate, hydroxyalkyl methacrylate and the like. And lactone modified products thereof. As the hydroxyalkyl acrylate, for example, the alkyl group has 1 to 6 carbon atoms.
2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and the like. Examples of hydroxyalkyl methacrylate include 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate having 1 to 6 carbon atoms in the alkyl group. Further, specific examples of the lactone-modified hydroxyalkyl acrylate and hydroxyalkyl methacrylate include lactone-modified 2-hydroxyethyl acrylate, lactone-modified 2-hydroxyethyl methacrylate, and the like.
The compounding ratio of the polymerizable monomer having a hydroxyl group and an unsaturated double bond in the polymerizable monomer mixture containing an unsaturated double bond is preferably 0.5 to 25% by weight,
More preferably, it is 0% by weight.

The polymerizable monomer (a3) having a carboxyl group and an unsaturated double bond used in the component (A) in the present invention includes, for example, acrylic acid, methacrylic acid, maleic acid and fumaric acid. And the like. The carboxyl group may be present as an acid anhydride group, and maleic anhydride or the like can be used. The above components are used alone or in combination of two or more. The mixing ratio of the polymerizable monomer having a carboxyl group and an unsaturated double bond in the polymerizable monomer mixture containing an unsaturated double bond is 0.1 to 10% by weight.
And more preferably 0.5 to 8% by weight. These monomers having an unsaturated double bond are used alone or in combination of two or more.

The weight average molecular weight of the component (A) is 10,000.
0 to 200,000 and 30,000 to 150,0
00 is preferred. Weight average molecular weight of 10,000
If it is less than 00, the dispersion stability at the time of polymerization and the weather resistance of the obtained coating film tend to be insufficient. If it exceeds 200,000, the amount of organic solvent necessary for dilution of the paint increases, so that the solidification of the paint becomes high. I can not plan. Here, the weight average molecular weight is a standard polystyrene conversion value by gel permeation chromatography. The glass transition temperature of the component (A) is in the range of -40C to 20C, and -30C to 10C.
Is preferably within the range. When the temperature is lower than -40 ° C, the finished appearance is remarkably deteriorated due to a decrease in drying property. When the temperature is higher than 20 ° C, the impact resistance is apt to be extremely lowered. here,
The glass transition temperature of the component (A) is determined by using a thermal analyzer DSC.
"Seiko Instrument Inc. products"
The value measured using is referred to.

In the present invention, as a method for polymerizing the component (A), a usual radical polymerization method can be used, and the method is not particularly limited. Preferably, the reaction is performed in the presence of an organic solvent and a polymerization initiator. A preferred reaction temperature is 50 to 200 ° C, and a particularly preferred reaction temperature is 70 to 150 ° C. Reaction time is 3-12
Preferably, it is time.

In the radical polymerization method, as the organic solvent, for example, an aromatic solvent, an aliphatic solvent, an ester solvent, a ketone solvent and the like can be used.
Examples of the aromatic solvent include, for example, toluene and xylene, and examples of the aliphatic solvent include, for example, heptane and
Hexane, petroleum benzine, lignoin, mineral spirit, petroleum naphtha, kerosene, and the like, and examples of the ester solvent include ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, amyl acetate, and the like. Examples of the system solvent include methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and the like. These organic solvents are used alone or in combination of two or more.

In the radical polymerization method, for example, an organic peroxide, an azobis compound or the like can be used as a polymerization initiator. As organic peroxides,
For example, isobutyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, benzoyl peroxide, t-butylcumyl peroxide, dicyclobenzoyl peroxide, dicumyl peroxide, dicumyl peroxide -T-butyl peroxide, 1,1-bis (t
-Butylperoxy) -3,3,5-trimethylcyclohexane, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, diisobutylperoxydicarbonate, 2-diethylhexylperoxydicarbonate, 2,5- Dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1
-Bis (t-hexylperoxy) cyclohexane,
1,1-bis (t-butylperoxy) cyclohexane, 2,2-bis (t-butylperoxy) butane, t
-Butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, t-butylperoxy-2-
Ethyl hexanoate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, and the like. Examples of the azo compound include, for example, 2,2'-azobisisobutyronitrile, dimethylazodiisobutyrate, and 2,2'-
Azobis (2,4-dimethylvaleronitrile), 2,
2'-azobis (2-methylbutyronitrile), 2,
2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), (1 phenylethyl) azodiphenylmethane, dimethyl-2,2'-azobisisobutyrate,
1,1'-azobis (1-cyclohexanecarbonyl), 2,2'-azobis (2,2,4-trimethylpentane), 2-phenylazo-2,4-dimethyl-4-
Methoxyvaleronitrile, 2,2'-azobis (2-methylpropane) and the like can be mentioned.

These polymerization initiators can be used alone or in combination of two or more. Upon polymerization, each of the polymerizable monomers may be added to the reaction system after being made into a mixture in advance, or may be separately added to the reaction system,
This mixture may be divided and added to the reaction system.

The amount of the polymerization initiator used is determined according to the desired molecular weight of the copolymer (A) component.
Usually, 0.1 to 10% by weight based on the total amount of the polymerizable monomer having an unsaturated double bond used for the polymerization of the component (A).
It is preferable that If necessary, the molecular weight may be adjusted using a chain transfer agent. Examples of the chain transfer agent include n-dodecyl mercaptan, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltriethoxysilane, and the like.

The non-aqueous dispersion type polymer (C) in the present invention
Is obtained by copolymerizing a copolymerizable monomer having an unsaturated double bond in the presence of a copolymer (A) and an organic solvent, and is insoluble in the organic solvent in the copolymer (A). (B) is contained.

The dispersed particles (B) insoluble in the organic solvent of the present invention
The polymerizable monomer having an unsaturated double bond used for the polymerization is not particularly limited as long as it has polymerizability, but preferably has a carbon-carbon double bond, and has a hydroxyl group. And does not have any of the carboxyl groups,
A polymerizable monomer having an unsaturated double bond (b1), a polymerizable monomer having a hydroxyl group and an unsaturated double bond (b
2) A polymerizable monomer (b3) having a carboxyl group and an unsaturated double bond is used. Examples of the polymerizable monomer (b1) having neither a hydroxyl group nor a carboxyl group and having an unsaturated double bond include, for example, methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, acryl Alkyl acrylates having 1 to 20 carbon atoms in alkyl groups such as 2-ethylhexyl acrylate and lauryl acrylate; cycloalkyl acrylates having 3 to 20 carbon atoms in cycloalkyl groups such as cyclohexyl acrylate; triacrylic acid Tricycloalkyl acrylates having 5 to 20 carbon atoms, such as cyclodecyl, tricyclodecyloxyethyl acrylate and tricyclodecyloxypropyl acrylate; methyl methacrylate, ethyl methacrylate, butyl methacrylate , Isobutyl methacrylate, Methacrylic acid t- butyl, 2-ethylhexyl methacrylate, the number of carbon atoms in the alkyl group of lauryl methacrylate 1
Alkyl methacrylates having a carbon number of 3 to 2 such as cyclohexyl methacrylate;
0 cycloalkyl methacrylate; tricyclodecyl methacrylate, tricyclodecyloxyethyl methacrylate, tricyclodecyloxypropyl methacrylate and the like having 5 to 20 carbon atoms in the tricycloalkyl group; Aminoalkyl methacrylate having an alkyl group having 1 to 20 carbon atoms, such as aminoethyl methacrylate and N, N-dimethylaminoethyl methacrylate; styrene, vinyltoluene, α-
Styrene-based monomers such as methylstyrene and t-butylstyrene; vinyl derivatives such as vinyl chloride, vinylidene chloride, vinyl acetate, isopropenyl acetate, glycidyl acrylate, glycidyl methacrylate, acrylamide and methacrylamide; dimethyl maleate; Dialkyl esters of unsaturated dibasic acids such as diethyl maleate, acrylates or methacrylates having a hindered amino group, acrylates or methacrylates having a benzotriazole group, acrylonitrile, methacrylonitrile and the like. Can be The above components are used alone or in combination of two or more.

Among the polymerizable monomers, at least one selected from alkyl acrylates and alkyl methacrylates is preferred in view of characteristics such as dispersion stability during polymerization, finished appearance of the coating film, and workability. It is preferable to use the polymerizable monomer of The amount of these polymerizable monomers used is preferably 70 to 100% by weight in the polymerizable monomer mixture having an unsaturated double bond, and is preferably 75 to 95% by weight.
It is more preferable to set the weight%.

The polymerizable monomer (b2) having a hydroxyl group and an unsaturated double bond used in the polymerization of the dispersed particles (B) in the present invention includes, for example, hydroxyalkyl acrylate and hydroxymethacrylate. Alkyl,
These lactone modified products are exemplified. Examples of the hydroxyalkyl acrylate include 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate in which the alkyl group has 1 to 6 carbon atoms. Examples of hydroxyalkyl methacrylate include 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate having 1 to 6 carbon atoms in the alkyl group. Further, specific examples of the lactone-modified hydroxyalkyl acrylate and hydroxyalkyl methacrylate include lactone-modified 2-hydroxyethyl acrylate, lactone-modified 2-hydroxyethyl methacrylate, and the like. The mixing ratio of the polymerizable monomer having a hydroxyl group and an unsaturated double bond in the polymerizable monomer mixture containing an unsaturated double bond is preferably 0.5 to 35% by weight, and 1 to 30% by weight. It is more preferable to set the weight%.

The polymerizable monomer (b3) having a carboxyl group and an unsaturated double bond used in the polymerization of the dispersed particles (B) in the present invention includes, for example, acrylic acid,
Examples include methacrylic acid, maleic acid, and fumaric acid.
The carboxyl group may be present as an acid anhydride group, and maleic anhydride or the like can be used. The above components are used alone or in combination of two or more. The compounding ratio in the polymerizable monomer mixture containing the unsaturated double bond of the polymerizable monomer having a carboxyl group and an unsaturated double bond is 0.1 to
It is preferably 10% by weight, more preferably 0.5 to 8% by weight. These monomers having an unsaturated double bond are used alone or in combination of two or more.

The organic solvent used for the polymerization of the component (A) can be used as it is as the organic solvent used for the polymerization of the component (B). The organic solvent is preferably present in an amount of 30 to 60 parts by weight based on 100 parts by weight of the component (A). In the resin composition for a coating material of the present invention, the hydroxyl value of the component (C) is preferably from 1 to 150 mgKOH / g. When the hydroxyl value is less than 1 mgKOH / g, the curability and solvent resistance of the resulting coating film tend to be insufficient, and
If it exceeds 0 mgKOH / g, the water resistance of the obtained coating film and the storage stability of the coating material tend to decrease. The acid value of the component (C) is preferably 1 to 60 mgKOH / g. If it is less than 1 mgKOH / g, the pigment dispersibility of the resulting coating film tends to decrease, and if it exceeds 60 mgKOH / g, the storage stability of the coating resin composition and the coating tends to be insufficient.

In the component (C) of the present invention, the mixing ratio of the component (A) is 3% of the total solid content of the components (A) and (B).
The content of the component (B) is 25 to 65% by weight. (B) The mixing ratio of the component is 2
When the amount is less than 5% by weight, the drying property and curability of the base coat and the finished appearance of the obtained coating film are inferior, and further, high solid differentiation of the coating material cannot be achieved. If it exceeds 65% by weight, the dispersion stability is poor, and the particles tend to aggregate and settle during synthesis or during storage. Further, for the purpose of improving dispersibility, the copolymer (A) component and the copolymer (B) component may be grafted.

The average particle size of the copolymer particle (B) component (for example, a value obtained by a scanning electron microscope (SEM),
Hereinafter the same) is preferably about 50 to 1000 nm, more preferably about 100 to 500 nm. If the average particle size is too small, the viscosity of the resin solution tends to be high, and if it is too large, the particles tend to swell or aggregate during storage, resulting in poor stability. The average particle diameter is determined by selecting the organic solvent, the molecular weight of the copolymer (A), the mixing ratio of the copolymer (A) component and the copolymer particle (B) component, and the solubility parameter (SP value). Adjusted. or,
In the present invention, as a method for polymerizing the component (B), a usual radical polymerization method can be used, and the method is not particularly limited. It is preferably carried out in the presence of a polymerization initiator. Preferred reaction temperatures are 50 to
200 ° C., and more preferred reaction temperature is 70-150.
° C. The reaction time is preferably 3 to 12 hours.

In the radical polymerization method, as a polymerization initiator, for example, an organic peroxide, an azobis compound or the like can be used. Examples of the organic peroxide include isobutyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, benzoyl peroxide, t-butylcumyl peroxide, and dicyclobenzoyl peroxide. , Dicumyl peroxide,
Di-t-butyl peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, diisobutylperoxydi Carbonate, 2-diethylhexyl peroxydicarbonate, 2,5-dimethyl-
2,5-bis (2-ethylhexanoylperoxy) hexane, 1,1-bis (t-hexylperoxy)-
3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-
Bis (t-butylperoxy) cyclohexane, 2,2
-Bis (t-butylperoxy) butane, t-butylhydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide,
Methyl ethyl ketone peroxide, cyclohexanone peroxide, t-butylperoxy-2-ethylhexanoate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-hexylperoxy-2- Ethyl hexanoate, t-butyl peroxyisobutyrate, and the like, and examples of the azo compound include, for example, 2,2'-azobisisobutyronitrile, dimethylazoisobutyrate, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), (1 phenylethyl) Azodiphenylmethane, dimethyl-2,2'-azobisisobutyrate, 1,1 '
-Azobis (1-cyclohexanecarbonyl), 2,
2'-azobis (2,2,4-trimethylpentane),
2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, 2,2'-azobis (2-methylpropane) and the like.

These polymerization initiators can be used alone or in combination of two or more. Upon polymerization, each of the polymerizable monomers may be added to the reaction system after being made into a mixture in advance, or may be separately added to the reaction system,
This mixture may be divided and added to the reaction system.

The amount of the polymerization initiator to be used is determined according to the desired polymerization rate of the copolymer (B).
Usually, 0.05 to 5% by weight based on the total amount of the polymerizable monomer having an unsaturated double bond used for the polymerization of the component (B).
It is preferable that If necessary, the particle size may be adjusted using a chain transfer agent. Examples of the chain transfer agent include n-dodecyl mercaptan, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltriethoxysilane, and the like.

As the blocked isocyanate of the component (D) in the present invention, a polyisocyanate compound blocked with an active methylene-based blocking agent for obtaining excellent effects of yellowing, low-temperature curability and storage stability is used. As the polyisocyanate compound, for example, tolylene diisocyanate, xylylene diisocyanate,
Phenylene diisocyanate, naphthalene diisocyanate, bis (isocyanatomethyl) cyclohexyl,
Isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, trimethylhexamethylene diisocyanate, and isophorone diisocyanate, and adducts, burettes, and isocyanurates thereof. Among the polyisocyanates, an isocyanurate of hexamethylene diisocyanate is preferred from the viewpoint of weather resistance.

Examples of the active methylene blocking agent include dimethyl malonate, diethyl malonate, methyl acetoacetate,
Examples include ethyl acetoacetate and acetylacetone.
In addition, the active methylene-based blocking agents can be used alone or in combination of two or more.

The mixing ratio of component (C) and component (D) is
It is preferable to mix them so that the weight ratio of (C) / (D) is 99/1 to 50/50, and 90/10 to 70/30.
It is more preferable to mix them such that When the weight ratio exceeds 99/1, the low-temperature curability, weather resistance, solvent resistance, and water resistance tend to decrease, and when the weight ratio is less than 50/50, the finished appearance and the storage stability of the paint tend to decrease. is there. This ratio is (A) / (B) = 85/1 by weight ratio.
A ratio of 5 to 75/25 is more preferable because the balance of coating film performance is excellent.

The resin composition for a coating used for the base coat in the present invention can be made into a one-pack type coating by blending a metallic powder and / or a coloring pigment. Examples of the metallic powder include aluminum powder, copper powder, and mica powder.Examples of the coloring pigment include inorganic pigments such as titanium oxide and carbon black, and organic pigments such as phthalocyanine blue, toluidine red, and benzidine yellow. Is mentioned. In addition, extenders such as calcium carbonate and barium sulfate can be added. It is also possible to use a clear coating without adding the pigment.
These pigments can be used alone or in combination of two or more.

As a method for forming a coating material of the present invention, for example, a known method such as a roll, a sand mill, a disperser and the like can be used. Further, when forming a coating with a non-aqueous dispersion resin, a high shear force is applied, and the resin may be agglomerated, so that a seed pen having good compatibility with the resin composition obtained by the present invention is used. Paints can also be made.
Further, for the purpose of improving the performance as a coating material, an acrylic polymer, a polyester polymer, a polyolefin resin, a urethane polymer, a polymer such as a crosslinked polymer particle, or a cellulose, if necessary, within a range not to impair the object of the present invention. Etc. may be contained. Examples of cellulose include cellulose butyrate acetate (CAB) and nitrocellulose (NC). As a method for incorporating cellulose or the like, for example, a usual pigment dispersion method can be used.

The resin composition for paint and the one-pack paint used in the base coat of the present invention may contain additives, if necessary.
For example, a plasticizer, a resin for strengthening a coating film, a dispersant, a pigment settling inhibitor, a coating surface adjuster, a rheology control agent, an ultraviolet absorber, an ultraviolet stabilizer, an antioxidant, etc. are added during or after coating. It is also possible. The resin composition for a coating material of the present invention can be directly applied directly to the surface of a plastic material such as polyurethane, polypropylene, or polycarbonate, but may be applied after a primer treatment for applying a primer in advance.

The coating resin composition of the present invention is preferably heated at 70 to 130 ° C. for 10 to 40 minutes after being applied to the material. The drying time can be shortened by heating. The heating and drying conditions are appropriately selected in consideration of the deformation temperature of the base material and the like.

The coating resin composition of the present invention comprises 2 coats 1
Bake (2C-1B) finish, 2 coats 2 bake (2C
2B) Finish, 3 coats 1 bake (3C-1B) finish, 3 coats 2 bake (3C-2B) finish, 3 coats 3 bake (3C-3B) finish or 1 coat 1 bake (1C-1B) finish method Further, the overcoat method is suitably used as a base coat in a coating method for forming a target laminated coating film. In general, the base coat refers to a colored coating film used to give a design to an object to be coated, and in some cases, also serves as a primer.

When the coating resin composition of the present invention is used as a base coat, a clear coat is generally formed thereon. The coating resin composition for the clear coat is not particularly limited as long as it can form a coating film, and typical examples thereof include a hydroxyl group and a carboxyl group-containing resin and a melamine resin. Composition, composition of hydroxyl group and carboxyl group-containing resin and polyisocyanate compound, composition of hydroxyl group and carboxyl group-containing resin and block polyisocyanate compound, composition of carboxyl group-containing resin and epoxy group-containing resin And a hydrolyzed silyl group-containing resin, and a composition using two or more of these can be used.

The method for applying the clear coat paint is not particularly limited, and various means can be employed. Preferred methods include electrostatic coating such as a bell type or air coating. No. In the above-mentioned coating method, usually, Ford Cup No. It is preferable to dilute the mixture so as to have a viscosity within a range of about 14 to 23 seconds with 4, and then apply the coating. The coating film thickness of each coating film is not particularly limited.
0 μm is preferable, and 25 to 35 μm is more preferable. In the case of a base coat, 5 to 25 μm is preferable.
20 μm is more preferred.

[0036]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In addition, parts and%
Represents parts by weight and% by weight, respectively. 1. Production of Copolymer (A) Solution Soluble in Organic Solvent 30 parts of methyl isobutyl ketone and toluene 20 were placed in a 1-liter four-necked flask equipped with a cooler, a thermometer, a dropping funnel, a nitrogen gas injection tube and a stirrer. Part 11
Heated to 0 ° C. Then, the mixed solution (a1
-A3) and 2,2'-azobisisobutyronitrile 0.
A mixture in which 6 parts were uniformly mixed was prepared and added dropwise over 3 hours while keeping the temperature at the same temperature, and then kept at the same temperature for 1 hour.
Further, 0.1 part of 2,2'-azobisisobutyronitrile was uniformly mixed with 10 parts of methyl isobutyl ketone, and then dropped into the four-necked flask over 30 minutes while keeping the same temperature. It was kept at the same temperature for 1 hour. And
The four-necked flask was cooled to room temperature, and methyl isobutyl ketone was added so that the heating residue of the reaction product was 60%, to obtain resin compositions (A-1) to (A-3). Table 1 shows the Tg (° C.) and weight average molecular weight of the copolymer measured by the above method.

[0037]

[Table 1]

2. Production of Non-Aqueous Dispersion-Type Polymer (C) Solution Using the synthesis apparatus used above, the solution of the copolymers (A-1) to (A-3) obtained above and mineral spirit 3
0 parts were charged and the temperature was raised to 110 ° C. Then, the mixture (b1 to b3) shown in Table 2 and t-butylperoxy-2-
A mixed solution in which 1.0 part of ethyl hexanoate was uniformly mixed was prepared and added dropwise over 3 hours while keeping the temperature at the same temperature.
Subsequently, 10 parts of butyl acetate, t-butyl peroxy-2
A mixture of 0.2 parts of ethylhexanoate was added dropwise over 30 minutes, and the mixture was further kept warm for 4 hours. Thereafter, the mixture was cooled and butyl acetate was added so that the heating residue became 50%, to obtain non-aqueous dispersion type polymers (C-1) to (C-7). Table 2 shows the hydroxyl value and the acid value.

[0039]

[Table 2]

3. Non-aqueous dispersion type polymers (C-1) to (C-
Preparation of base coat paint using 7) Non-aqueous dispersion type polymers (C-1) to (C-
Using 7), other components were blended at the blending ratios shown in Tables 3 and 4, and the components were mixed and dispersed according to a conventional method to obtain a base coat paint. Ethyl acetate / ethyl 3-ethoxypropionate = 50/50 (solution mixed at a weight ratio), diluted with Ford cup # 4 to 12-14 seconds / 25 ° C. to obtain a base coat paint. . The coating solid content at this time is also shown in Table 5.

[0041]

[Table 3]

[0042]

[Table 4]

4. Preparation of Clear Coating Paint 100,275 parts by weight of Solvesso was charged into a 1-liter four-necked flask equipped with a cooler, a thermometer, a dropping funnel, a nitrogen gas injection tube and a stirrer, and heated to 140 ° C. Thereafter, 100 parts by weight of styrene, 2-methacrylic acid 2-
55 parts by weight of ethylhexyl, 166 parts by weight of 2-ethylhexyl acrylate, 174 parts by weight of 2-hydroxyethyl methacrylate, 5 parts by weight of methacrylic acid and 3.0 parts by weight of t-butylperoxy-2-ethylhexanoate The mixture thus prepared was adjusted and added dropwise over 3 hours while keeping the temperature at the same temperature, and then kept at the same temperature for 2 hours. Then, the four-necked flask was cooled to room temperature, and butyl acetate was added so that the heating residue of the reaction product became 60% to obtain a resin composition.

200 parts of the resin composition obtained above and 65 parts of polyisocyanate (Sumijur N3500, trade name, manufactured by Sumitomo Bayer Urethane Co., Ltd.) were mixed to obtain a clear coating. Using a thinner (ethyl acetate / ethyl 3-ethoxypropionate = 50/50 mixed solution by weight) with Ford Cup No. 14 to 16 seconds / 25 at 4
C. to obtain a clear coat paint.

5. Preparation of paint for primer coat As a paint for primer coat, acrylic resin (Hitaloid 1352, manufactured by Hitachi Chemical Co., Ltd., solid content 35%)
143 parts, chlorinated polyolefin (manufactured by Nippon Paper Industries,
A coating material was prepared by mixing 250 parts of Supercron (851 L, solid content: 20%) and 390 parts of thinner (a mixed solution of toluene / solvesso 100 at a weight ratio of 50/50).

(Preparation of Coating Film Sample) The above-mentioned primer coating material was coated on a polypropylene molded plate (Noblen BC-3).
B, polypropylene manufactured by Mitsubishi Chemical Corporation) so that the dry film thickness of the paint for primer coating would be in the range of 5 to 10 μm, followed by forced drying at 80 ° C. for 10 minutes. Thereafter, the dry film thickness of the base coat paint obtained above was 10
After coating to within the range of
After leaving for 5 minutes, the clear coat paint obtained above is applied on a wet-on-wet basis so that the dry film is in the range of 25 to 35 μm.
After standing for 0 minutes, baking was performed at 80 ° C. for 20 to 40 minutes.
That is, a coating film was prepared from the base coat paint and the clear coat paint by two coats and one bake (2C to 1B).

(Evaluation) With respect to the obtained coated plate, the storage stability, coating solid content, finished appearance, gel fraction, adhesion (initial adhesion and hot water treatment) of the obtained resin composition for coating were obtained according to the following methods. After adhesion), gasoline resistance, impact resistance,
Table 5 shows the evaluation results of the weather resistance.

[0048]

[Table 5]

(Storage Stability) The obtained resin composition for coating was placed in a 50 ml container and stored in an atmosphere at 40 ° C. for 10 days. The difference from the viscosity before storage was measured and evaluated according to the following criteria. The condition of the resin composition for coatings was visually evaluated according to the following criteria. Thickening time 2 seconds or less: ◎ Very good storage stability 3 to 5 seconds: ○ Good storage stability 6 to 10 seconds: △ Poor storage stability 10 seconds or more: × Very poor storage stability Appearance No bumps: ○ Good storage stability Discoloration: △ Relatively good storage stability Discoloration and bumps: × Poor storage stability

(Finish appearance) The obtained coating film test piece was visually evaluated according to the following criteria. No unevenness in the orientation of the aluminum pigment was observed at all: 良好 Good A slight unevenness was observed in the orientation of the aluminum pigment: Slightly poor The unevenness was noticeably observed in the orientation of the aluminum pigment: X

(Gel Fraction) After the obtained coating film test piece was extracted with a mixed solution of acetone / methanol = 50/50 (weight ratio) for 4 hours, the weight change of the coating film test piece was measured, and the following criteria were used. The low-temperature curability was evaluated. 90% or more: ◎ Very good low-temperature curability 80-89%: ○ Good low-temperature curability 60-79%: △ Slightly low-temperature curability 59% or less: × Poor low-temperature curability

(Adhesion (initial adhesion)) JIS K-5
A 400 Goban test method was followed. On the coating film, 100 lines were created by drawing 10 lines each vertically and horizontally at 1 mm intervals with a knife, and a cellophane tape was stuck on it,
The tape was peeled off, the number of gobangs remaining on the coating film was measured, and evaluated according to the following criteria. 100/100: が Good adhesion 51-99 / 100: が Slightly poor adhesion 50/100 or less: × Very poor adhesion

(Water Resistance (Adhesion after Hot Water Treatment)) The obtained coating film test piece was immersed in warm water at 40 ° C. for 240 hours, and then the adhesion was evaluated according to the method for evaluating initial adhesion. 100/100: が Good adhesion 51-99 / 100: が Slightly poor adhesion 50/100 or less: × Very poor adhesion

(Gasoline resistance) The obtained coating film test piece was immersed in Nisseki regular gasoline, and the presence or absence of peeling of the coating film was evaluated according to the following criteria. No peeling for 2 hours or more: ◎ Very good gasoline resistance No peeling for more than 1 hour and less than 2 hours: ○ Good gasoline resistance 30 minutes to 1 hour No peeling: △ Poor gasoline resistance Within 29 minutes With peeling: × Poor gasoline resistance

(Impact Resistance) The state of the coating film when a 1 kg weight was dropped on a coating film test piece obtained from a height of 50 cm was examined using a DuPont impact tester, and evaluated according to the following criteria. did. No cracks in the coating: ○ Good impact resistance Cracks in the coating: × Poor impact resistance

(Weather resistance) The obtained coating film test piece was subjected to a sunshine weatherer meter (S-8, manufactured by Suga Test Instruments Co., Ltd.).
(Type 0) for 1500 hours, and then the state of the coating film was evaluated according to the following criteria. No crack in coating film, no discoloration: ○ (good weather resistance) No crack in coating film, discoloration: △ (slightly poor weather resistance) Crack in coating film, discoloration: × (poor weather resistance)

[0057]

Industrial Applicability The resin composition for coatings according to the present invention is useful for plastic materials, and can be particularly used as a one-component base coat, and is excellent in environmental friendliness, workability and finish appearance. Can be formed.
Further, the coating method of the present invention, by using the resin composition for coating, even for plastic materials, low-temperature curability, water resistance, impact resistance, solvent resistance, excellent properties such as weather resistance. It forms a coating film.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 5/00 C09D 5/00 Z 175/04 175/04 (72) Inventor Kenichi Shintani Hazaki, Kashima-gun, Ibaraki Prefecture F-term (reference) 4D075 AE06 CA47 DA06 DB02 DC13 EA02 EA05 EB22 EB38 EB52 EB53 EB55 EB56 EC30 4J011 AA05 PA69 PB38 4J026 AA42 AAA AA AA AA AA AA AA AA AA AA A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A AA A BA30 BA31 BA32. NA23 NA26 NA27 PA07 PA19 PB07 PC08

Claims (5)

[Claims] A weight average molecular weight obtained by copolymerizing a polymerizable monomer having an unsaturated double bond is 10,000 to 1.
A copolymerizable polymerizable monomer having an unsaturated double bond is copolymerized in the presence of a copolymer (A) soluble in an organic solvent having a glass transition temperature of -40 to 20 ° C at 200,000 and an organic solvent. A non-aqueous dispersion type polymer (C) containing dispersed particles (B) insoluble in an organic solvent in the copolymer (A),
The blending ratio of (B) is 2 of the total solid content of (A) and (B).
A coating resin composition comprising a non-aqueous dispersion polymer (C) in an amount of 5 to 65% by weight and a blocked isocyanate (D) blocked with an active methylene-based blocking agent. 2. The coating resin composition according to claim 1, wherein the organic solvent is at least one organic solvent selected from an aromatic solvent, an aliphatic solvent, a ketone solvent and an ester solvent. 3. The non-aqueous dispersion type polymer (C) has a hydroxyl value of 1
~ 150mgKOH / g, acid value is 1 ~ 60mgKOH / g
g. The resin composition for paints according to claim 1 or 2. 4. The mixing ratio of the non-aqueous dispersion type polymer (C) and the blocked isocyanate (D) is from 99/1 to 50/50 in weight ratio of (C) / (D). Or the resin composition for a coating according to 3. 5. The coating resin composition according to claim 1, 2, 3 or 4, 2 coats 1 bake finish, 2 coats 2 bake finishes, 3 coats 1 bake finishes, 3 coats 2 bake finishes, 3 coats 3 A coating method characterized by being used as a base coat having a bake finish or one coat and one bake finish.