JPH09235487A - Thermosetting waterborne resin composition, method for producing the same, waterborne coating composition, coating method and coated article - Google Patents

Abstract

(57) [Abstract] [Problem] To ensure good workability under a wide range of humidity conditions,
Provided is a water-based coating composition which is excellent in coating stability, coating appearance and coating physical properties. A film-forming polymer obtained by copolymerizing an ethylenic monomer having a saturated hydrocarbon group having 6 to 18 carbon atoms, a hydroxyl group-containing ethylenic monomer, an acidic group-containing ethylenic monomer and other ethylenic monomers. (A) 50 to 90% by weight, and polyester resin (B) 50 to 10% by weight having a hydroxyl group at the terminal,
A thermosetting aqueous resin obtained by grafting (B) above onto (A) by a transesterification reaction, and neutralizing at least a part of the acidic groups in (A) above with a base (C). Method for producing thermosetting water-based resin which carries out transesterification reaction at 130 to 200 ° C., water-based coating composition obtained by blending thermosetting water-based resin with a curing agent, and 2 coats using the water-based coating composition as a base coat 1 Bake coating method.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention provides an aqueous coating composition which has good workability under a wide range of humidity conditions from high humidity to low humidity, and has good storage stability, coating film appearance and coating film physical properties. The present invention relates to a thermosetting aqueous resin composition capable of producing, a method for producing the same, an aqueous coating composition, a coating method, and a coated article.

[0002]

2. Description of the Related Art In the coating of automobiles, a metallic base paint containing a metallic pigment, which is referred to as an overcoat, is applied to a paint plate which has been subjected to an undercoat and an intermediate coat, and then the wet coating is carried out without curing this paint film. A two-coat, one-bake method is used in which clear paint is applied repeatedly by on-wet coating and cured with the clear paint.

As a coating material used in the two-coat one-bake method, an organic solvent type coating material has hitherto been the mainstream. However, from the viewpoint of safety at the time of painting, reduction of environmental pollution, resource saving, and the like, in recent years, a shift to water-based paints has been strongly desired. Therefore, various water-based paints for automobiles have been developed.

For example, JP-A-4-25582 discloses an aqueous metallic base coating composition containing an aqueous dispersion of an amide group-containing acidic resin and a hydrophilic group-carrying polyurethane resin as a main component. However, under this high humidity condition where the humidity during coating is 80% or more, "drip" occurs on the vertical surface, and if the humidity during coating is less than 65%, the smoothness of the coating film is insufficient. It was

Japanese Patent Application No. 5-198329 proposes an aqueous coating composition containing an amide group-containing acrylic resin and a polycarbonate resin as main components. However, this has a problem in coating workability such as "drip" or "tumble" occurring on a vertical surface in a high humidity environment where the humidity during coating is about 85 to 90%. Further, storage stability is poor due to poor compatibility between the hydrophobic polycarbonate resin and the hydrophilic acrylic resin, and the appearance, mechanical properties, water resistance, chemical resistance and other physical and chemical properties of the resulting coating film. The various characteristics were insufficient.

On the other hand, JP-A-4-233926 discloses that a core of an epoxy resin containing a conjugated double bond and a shell onto which an addition polymer of a monomer capable of free-radical polymerization is grafted are used, and coating film performance is improved. Excellent hybrid polymers are disclosed. However, this product has a weak interaction between particles in the case of being made into an aqueous dispersion, and the expression of viscosity is insufficient, so that the sagging property is a problem.

Further, in Japanese Patent Laid-Open No. 7-74320,
An aqueous coating composition has been proposed which uses an aqueous dispersion resin composition having an acrylic resin as a core and a polyester resin as a shell and has good workability under a wide range of humidity conditions from high humidity to low humidity. However, this product was inferior in storage stability because the polyester resin arranged in the shell portion was susceptible to hydrolysis.

[0008]

SUMMARY OF THE INVENTION In view of the above situation, the present invention can secure good workability under a wide range of humidity conditions from high humidity to low humidity, stability of paint, appearance of coating film. Another object of the present invention is to provide a thermosetting aqueous resin composition capable of obtaining an aqueous coating composition having excellent coating film properties, a method for producing the same, an aqueous coating composition, a coating method and a coated article.

[0009]

Means for Solving the Problems As a result of continuous studies to solve the above problems, the present inventors have found that an acrylic resin containing a specific amount of an ethylenic monomer having a saturated hydrocarbon group having 6 or more carbon atoms. In order to complete the present invention, it was found that the above object can be achieved by an aqueous resin composition containing, as a main component, and a polyester resin, and a part of the polyester resin grafted to an acrylic resin by a transesterification reaction. I arrived.

That is, the gist of the present invention lies in the following points. [1] A film-forming polymer obtained by copolymerizing an ethylenic monomer having a saturated hydrocarbon group having 6 to 18 carbon atoms, a hydroxyl group-containing ethylenic monomer, an acidic group-containing ethylenic monomer and other ethylenic monomers (A) 50 to 90% by weight, and polyester resin (B) 50 to 10% by weight having a hydroxyl group at the terminal,
The total of (A) and (B) is 100% by weight, the film-forming polymer (A) and the polyester resin (B) are grafted by a transesterification reaction, and the film-forming weight is A thermosetting water-based resin composition itself obtained by neutralizing at least a part of the acidic groups in the polymer (A) with a base (C).

[2] A water-based coating composition prepared by blending a thermosetting water-based resin composition with a curing agent. [3] A water-based coating composition prepared by blending the thermosetting water-based resin composition with the curing agent, and further adding a polymer thickener (hereinafter referred to as “water-based coating composition (II)”). ). [4] A pigment-containing aqueous coating composition obtained by further adding a pigment to the above-mentioned aqueous coating composition or by further adding a pigment to the above-mentioned aqueous coating composition (II).

[5] As the method for producing the thermosetting aqueous resin composition, an ethylenic monomer having a saturated hydrocarbon group having 6 to 18 carbon atoms, a hydroxyl group-containing ethylenic monomer, an acidic group-containing ethylenic monomer and others 50% to 90% by weight of a film-forming polymer (A) obtained by copolymerizing the above ethylenic monomer, and 50% to 10% by weight of a polyester resin (B) having a hydroxyl group at the terminal, A total of 100% by weight with (B) is subjected to a transesterification reaction at 130 to 200 ° C., and then at least a part of the acidic groups contained in the film-forming polymer (A) is converted into a base (C). Neutralize with. [6] A two-coat / one-bake coating method using the above pigment-containing aqueous coating composition as a base coat. [7] A coated article obtained by applying the above-mentioned aqueous coating composition, the aqueous coating composition (II) or the above pigment-containing aqueous coating composition. [8] A coated article coated by the above coating method. Hereinafter, the present invention will be described in detail.

The thermosetting aqueous resin composition of the present invention comprises a film-forming polymer (A) and a polyester resin (B). The film-forming polymer (A) is obtained by copolymerizing an ethylenic monomer having a saturated hydrocarbon group having 6 to 18 carbon atoms, a hydroxyl group-containing ethylenic monomer, an acidic group-containing ethylenic monomer and other ethylenic monomers. Is.

The ethylenic monomer having a saturated hydrocarbon group having 6 to 18 carbon atoms is not particularly limited, and examples thereof include acrylic acid and methacrylic acid whose ester moiety has 6 to 18 carbon atoms. . Specific examples of such compounds include, for example, hexyl acrylate,
Hexyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, ethylhexyl acrylate, ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate, lauryl stearyl acrylate, stearyl acrylate and the like can be mentioned. Further, it may be a reaction product of a functional group-containing ethylenic monomer and a compound having a saturated hydrocarbon group having 6 to 18 carbon atoms which reacts with the functional group. Examples of such substances include a reaction product of glycidyl methacrylate and lauric acid or stearic acid, and a reaction product of methacryl isocyanate with lauryl alcohol or stearyl alcohol.

In the present invention, the carbon number is 6-18.
Since the ethylenic monomer having a saturated hydrocarbon group has a moderate bulkiness, it enhances the structural viscosity of a coating composition using the resulting thermosetting aqueous resin composition and makes the characteristics of the coating composition suitable. can do.

The hydroxyl group-containing ethylenic monomer is not particularly limited, and examples thereof include 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate and 2-hydroxyethyl methacrylate. Hydroxypropyl methacrylate, 2,4-
Dihydroxy-4'-vinylbenzophenone, N- (2
-Hydroxyethyl) acrylamide, N- (2-hydroxyethyl) methacrylamide and the like can be mentioned.

The acidic group-containing ethylenic monomer is not particularly limited, and examples thereof include a carboxyl group-containing monomer, and examples thereof include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid; Examples thereof include styrene derivatives such as 3-vinylsalicylic acid and 3-vinylacetylsalicylic acid.

The above-mentioned acidic group-containing ethylenic monomer may also be a half ester, half ester amide or half thioester of a dibasic acid monomer.
Examples of such compounds include maleic acid, fumaric acid, itaconic acid half ester, half amide, and half thioester. In this case, as the alcohol forming the half ester, for example, methanol, ethanol, propanol, butanol, methyl cellosolve, ethyl cellosolve, dimethylaminoethanol, diethylaminoethanol, acetol, allyl alcohol, propargyl alcohol, etc. To 12 alcohols and the like. Of these, butanol, dimethylaminoethanol, diethylaminoethanol, acetol,
Allyl alcohol and propargyl alcohol are preferred.

The mercaptan forming the half thioester is, for example, ethyl mercaptan, propyl mercaptan, butyl mercaptan or the like having 1 to 1 carbon atoms.
2, mercaptan and the like can be mentioned. Examples of the amine forming the half amide include amines having 1 to 12 carbon atoms such as ethylamine, diethylamine, butylamine, cyclohexylamine, aniline and naphthylamine.

A half ester of the above dibasic acid monomer,
Among the half ester amides and half thioesters, half thioestyl has a slight problem in terms of odor. Half-esters and half-amides do not have such a problem and can be preferably used.

A half ester of the above dibasic acid monomer,
In the half ester amide and half thioester,
Each reaction of half esterification, half thioesterification, half amidation can be carried out by a usual method,
For example, it can be carried out in the temperature range of room temperature to 120 ° C., if necessary, using a tertiary amine as a catalyst.

The above-mentioned other ethylenic monomer is not particularly limited, and other than the above-mentioned ethylenic monomer having a saturated hydrocarbon group having 6 to 18 carbon atoms, a hydroxyl group-containing ethylenic monomer, and an acidic group-containing ethylenic monomer. Examples thereof include ethylenic monomers having no reactive functional group. Examples thereof include styrenes such as styrene and α-methylstyrene; acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; methyl methacrylate, methacrylic acid. Methacrylic acid esters such as ethyl, butyl methacrylate, isobutyl methacrylate, p-butyl methacrylate and 2-ethylhexyl methacrylate; nitriles such as acrylonitrile; olefins such as ethylene and propylene. In addition, acrylamide,
An amide group-containing ethylenic monomer such as N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, or N, N-dibutylacrylamide may be used.

In the present invention, the carbon number is 6-18.
The ethylenic monomer having a saturated hydrocarbon group, a hydroxyl group-containing ethylenic monomer, and an acidic group-containing ethylenic monomer are, in principle, different from each other, but in a range consistent with the constitution of the present invention, It may be a monomer containing a hydroxyl group and an acidic group.

The content of the ethylenic monomer having a saturated hydrocarbon group having 6 to 18 carbon atoms in the above film-forming polymer (A) is preferably 30 to 80% by weight. If the amount is less than 30% by weight, the interaction between particles is weak and "sag" tends to occur. If the amount exceeds 80% by weight, the amount of the acidic group-containing ethylenic monomer and the amount of the hydroxyl group-containing ethylenic monomer are insufficient, and curing Properties and water dispersion stability are reduced. More preferably, it is 40 to 60% by weight.

The film-forming polymer (A) preferably has a hydroxyl value of 50 to 200 mgKOH / g. If the hydroxyl value is less than 50 mgKOH / g, the curability of the coating film will be poor, and if it exceeds 200 mgKOH / g, the water resistance of the coating film will be reduced. More preferably, it is 60 to 150.
mg KOH / g. The hydroxyl value can be achieved by adjusting the amount of the hydroxyl group-containing ethylenic monomer used to 2 to 40% by weight.

The film forming polymer (A) preferably has an acid value of 10 to 100 mgKOH / g. If the acid value is less than 10 mgKOH / g, the water dispersibility is poor, and if it exceeds 100, the water resistance of the coating film is reduced. More preferably, it is 20-60 mgKOH / g. The acid value can be achieved by adjusting the amount of the acidic group-containing ethylenic monomer used to 2 to 60% by weight, preferably 4 to 40% by weight.

The above film-forming polymer (A) preferably has a number average molecular weight of 5,000 to 100,000. When the number average molecular weight is less than 5,000, the hardness and water resistance of the coating film decrease, and when it exceeds 100,000, atomization during spray coating deteriorates and the smoothness of the coating film decreases.
More preferably, it is 10,000 to 60,000.

The film-forming polymer (A) is obtained by copolymerizing the above monomer components.
In this case, the above-mentioned copolymerization can be carried out by a known method or the like. For example, the initiator and the monomer mixture are dropped into a heated solvent with heating to obtain a copolymer. In this case, in a preferred embodiment, the polymerization initiator and the monomer mixture are simultaneously added dropwise to a solution containing the polyester resin (B) described in detail later for 1 to 5 hours, preferably 2 to 3 hours. , Then 0
Examples include a method of maintaining the polymerization temperature for 4 hours, preferably 1 to 2 hours.

In the film-forming polymer (A), at least a part of the acidic groups contained therein is neutralized with the base (C). The base (C) is not particularly limited, and examples thereof include ammonia, methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, dimethylethanolamine, diethanolamine, and triethanolamine. Of these, diethanolamine, dimethylethanolamine and triethanolamine are preferable.

In this case, the proportion of acidic groups to be neutralized is not particularly limited, and the thermosetting aqueous resin composition of the present invention is neutralized with the above base (C) to such an extent that it can be dispersed in water. . For example, it may be an appropriate ratio such as about 50%, and for example, an amount of a molar ratio of 0.4 to 2.0, preferably 0.6 to 1.4 with respect to the number of moles of the acidic group contained. The amine can be preferably used for neutralization and so-called post-emulsification.

The polyester resin (B) has a hydroxyl group at the terminal. The polyester resin (B)
Can be obtained by polyesterification of a polyol with a polycarboxylic acid or an acid anhydride. The polyol is not particularly limited, and examples thereof include tetraols such as pentaerythritol and dimers of trimethylolpropane; triols such as trimethylolpropane and hexanetriol; 1,9-nonanediol, 2-methyl-
1,8-octanediol, neopentyl glycol,
Hydroxypivalic neopentyl glycol, 3-methyl-1,5-pentanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-butanediol, 2-methyl-1,3-propylene glycol,
Examples include propylene glycol, hexylene glycol, ethylene glycol, diethylene glycol, hydrogenated bisphenol A, caprolactone diol, bishydroxyethyl taurine, diols such as dimer acid reductants, and the like.

In particular, as the above-mentioned polyol, a conjugated alkadiene diol having a polymerization degree of 5 to 50, a hydrogenated product thereof, or a mixture thereof is used.
The features of the present invention are remarkably exhibited. These diols are derived from conjugated alkadiene oligomers or polymers with a degree of polymerization of 5 to 50. Its molecular weight is 1000-4
000, and particularly preferably in the range of 1500 to 3000. Specifically, for example, 1,4-polyisoprene diol, 1,4- and 1,2-polybutadiene diol, and hydrogenated products thereof are preferable. These are available as commercial products, and Epol (trade name) (hydrogenated polyisoprene diol, molecular weight 1860, average degree of polymerization 2
6, manufactured by Idemitsu Petrochemical Co., Ltd., PIP (trade name) (polyisoprene diol, molecular weight 2200, average degree of polymerization 34, manufactured by Idemitsu Petrochemical Co., Ltd.), Polytail HA (trade name) (hydrogenated polybutadiene diol, molecular weight 2200, average) Polymerization degree 39, manufactured by Mitsubishi Kasei Co., Ltd., Polytail H (trade name)
(Hydrogenated polybutadiene diol, molecular weight 2350, average degree of polymerization 42, manufactured by Mitsubishi Kasei Co., Ltd.), R-45HT (trade name) (polybutadiene diol, molecular weight 2270, average degree of polymerization 42, manufactured by Idemitsu Petrochemical Co., Ltd.) and the like are exemplified. be able to. By using such a diol as a part of the polyhydric alcohol component, the polyester resin is hydrophobized, the core in the core / shell structure is easily formed, and the polyester resin is less susceptible to hydrolysis.
Further, water is released well, so-called water releasability is improved, and workability can be improved.

The polycarboxylic acid is not particularly limited, and examples thereof include isophthalic acid, terephthalic acid, tetrahydrophthalic acid, adipic acid, trimellitic acid, azelaic acid, sebacic acid, succinic acid, cyclohexanedicarboxylic acid, maleic acid and dimer. An acid etc. can be mentioned. The acid anhydride is not particularly limited, and examples thereof include acid anhydrides of the above polycarboxylic acids.

The polyester resin (B) preferably has a number average molecular weight of 500 to 10,000.
When the number average molecular weight is less than 500, the hardness and water resistance of the coating film decrease, and when it exceeds 10,000, the smoothness of the coating film decreases. It is more preferably 800 to 8000, and even more preferably 1000 to 6000.

The above polyester resin (B) has an acid value of 1
It is preferably less than 5 mg KOH / g. When the acid value is 15 mgKOH / g or more, the water resistance of the coating film decreases. It is more preferably less than 10 mgKOH / g, and even more preferably less than 8 mgKOH / g.

The above polyester resin (B) can impart flexibility and flexibility to the coating film. Further, since it is a hydrophobic resin, it is possible to improve workability, particularly workability.

A monoepoxy compound may be added to the polyester resin (B) in order to further impart flexibility. Examples of the monoepoxy compound include cardura EIO, YOA10, YOA20, and YO.
A30 (Daicel Chemical Industries, Ltd. aliphatic monoepoxy compound) etc. can be mentioned.

The thermosetting aqueous resin composition of the present invention comprises the above film-forming polymer (A) and the above polyester resin (B).
50 to 90% by weight of the above film-forming polymer (A) and 50 to 10% by weight of the above polyester resin (B) based on the total resin solid content. When the film-forming polymer (A) is less than 50% by weight and the polyester resin (B) exceeds 50% by weight, the amount ratio of the hydrophilic portion responsible for water dispersibility of the thermosetting aqueous resin composition is increased. Insufficient water dispersion stability decreases, and the film-forming polymer (A) is 90%.
When the content of the polyester resin (B) is more than 10% by weight and the content of the polyester resin (B) is less than 10% by weight, the properties of the polyester resin are not utilized and the workability and the water dispersibility are deteriorated. Preferably, the film-forming polymer (A) 60 to
80% by weight, 40 to 20% by weight of the polyester resin (B).

In the present invention, the polyester resin (B) is more hydrophobic than the film-forming polymer (A). That is, for the water and hexane tolerance of the film-forming polymer (A), for example, 0.5 g of the film-forming polymer (A) was dissolved in 10 mL of tetrahydrofuran, and a 0.1N aqueous potassium hydroxide solution was added dropwise until it became cloudy. In this case, the dropping amount is in the range of 2.3 L to 9.26 mL, and the dropping amount of hexane is 20.60 to 45.30 m.
Whereas in the case of the polyester resin (B), the dropping amount when the 0.1N potassium hydroxide aqueous solution is dropped is in the range of 0.22 to 1.89 mL, which is in the range of 0.2 to 1.89 mL. Dropping amount is 25.20 to 45.90 m
L. Therefore, when the thermosetting aqueous resin composition of the present invention is dispersed in an aqueous medium, the more hydrophilic film forming polymer (A) serves as a shell at the surface layer portion, and the more hydrophobic polyester resin ( It is considered that core / shell type dispersed particles, which are B) inside and serve as a core, are formed, and the viscosity exhibited by the particles can improve workability.

In the thermosetting aqueous resin composition of the present invention, at least a part of the polyester resin (B) is grafted onto the film-forming polymer (A) by a transesterification reaction, and the film-forming polymer is formed. At least a part of the acidic groups in (A) is neutralized. Therefore, the thermosetting aqueous resin composition of the present invention is a so-called core in which the hydrophobic polyester resin (B) is disposed inside in an aqueous medium, and the hydrophilic film-forming polymer (A) is It is considered that when it is arranged in the surface layer portion, it becomes a so-called shell, and particles having a structure in which these are firmly bonded to each other to the extent that they cannot be easily separated can be formed. Further, with the above structure, the thermosetting aqueous resin composition of the present invention can avoid direct contact of the polyester resin with water, so that the possibility of hydrolysis of the polyester resin and the like can be avoided. The thermosetting aqueous resin composition of the present invention has 10
It has a particle size of ~ 1000 nm and is stable. 80 ~
By setting the thickness to 250 nm, the stability is further improved.

The thermosetting aqueous resin composition of the present invention has the above-mentioned characteristics and is disclosed in JP-A-4-233926.
The resin composition disclosed in Japanese Patent Publication No.
They are completely different in composition and the like, and can exhibit unique effects that these inventions never suggest.

The thermosetting aqueous resin composition of the present invention can be suitably produced by the second present invention [II] described in detail below. In the second invention [II], an ethylenic monomer having a saturated hydrocarbon group having 6 to 18 carbon atoms, a hydroxyl group-containing ethylenic monomer, an acidic group-containing ethylenic monomer and another ethylenic monomer are copolymerized. The film-forming polymer (A) 50 thus obtained
To 90% by weight and polyester resin (B) having a hydroxyl group at the end of 50 to 10% by weight at a ratio such that the total amount of (A) and (B) becomes 100% by weight.
The thermosetting aqueous resin composition is obtained by transesterifying at ~ 200 ° C, and then neutralizing at least a part of the acidic groups contained in the film-forming polymer (A) with a base (C). To manufacture.

In this case, the film-forming polymer (A) and the polyester resin (B) are, for example, the film-forming polymer (A) polymerized in an organic solvent and then a predetermined amount of the polyester resin. The film-forming polymer (A) can be polymerized and reacted in a mixture with (B) or in an organic solvent in which a predetermined amount of the polyester resin (B) is charged in advance.

The organic solvent is not particularly limited, and examples thereof include Solvesso 150 (S-150) (manufactured by Shoei Chemical Industry Co., Ltd.), aromatic hydrocarbons such as xylene; esters such as butyl acetate; γ-butyrolactone. And the like; ethers such as dibutyl ether and ethylene glycol diethyl ether; ketones such as methyl isobutyl ketone; ether esters such as propylene glycol monomethyl ether acetate; amides such as N-methylpyrrolidone. . These can be used in combination of two or more.

In the second invention [II], the transesterification reaction is carried out by heating the film-forming polymer (A) and the polyester resin (B). In the present invention, by heating the film-forming polymer (A) and the polyester resin (B) in this way, the hydroxyl groups in the film-forming polymer (A) and the polyester resin (B) are transesterified. It is possible to react at least a part of the polyester resin (B) onto the film-forming polymer (A) by reacting it with the ester bond in (). The reaction temperature of the heating reaction is 130 to 200 ° C. If the temperature is lower than 130 ° C., the progress of the reaction is not sufficient and the stability of the thermosetting aqueous resin composition obtained is not observed, and if the temperature is higher than 200 ° C., the coloring of the thermosetting aqueous resin composition obtained is colored. And the appearance is deteriorated, so the content is limited to the above range. It is preferably 140 to 180 ° C.

In the second invention [II], after the heating reaction, the base (C) is added to neutralize at least a part of the acid groups contained in the film-forming polymer (A). By emulsifying the mixture with water, the thermosetting aqueous resin composition of the present invention can be easily obtained.

In the second invention [II], by carrying out the transesterification reaction by heating, the grafting of the polymers can be easily carried out, and the existing equipment can be utilized. It is extremely convenient for industrial production.

The thermosetting aqueous resin composition of the present invention can be easily dispersed in water by being neutralized with a base to obtain the aqueous resin aqueous dispersion of the present invention.

The aqueous coating composition of the present invention comprises the above thermosetting aqueous resin composition, which has been described in detail above, and a curing agent. Examples of the curing agent include amino resins and blocked isocyanates. Specific examples of the amino resin include, for example, dimethylolmelamine, trimethylolmelamine, tetramethylolmelamine, pentamethylolmelamine, hexamethylolmelamine; their methyl ethers, ethyl ethers, propyl ethers, isopropyl ethers, butyl ethers, isobutyl ethers, etc. Alkyl ether compound of; a urea-formamide condensate, a urea-melamine condensate, and the like. Since the thermosetting aqueous resin composition of the present invention has the above-mentioned graft structure even when hydrophobic melamine is used as a curing agent, it can be stably dispersed in water.

Specific examples of the blocked isocyanates include aromatic isocyanates such as tolylene diisocyanate, xylylene diisocyanate and diphenylmethane diisocyanate; methylcyclohexylene-2,4 (2,6) -diisocyanate, 1,3 ( 4)
-(Diisocyanatomethyl) cyclohexane, 4,4-
Alicyclic isocyanate such as bis (isocyanatocyclohexyl) methane; Aliphatic isocyanate such as hexamethylene diisocyanate, lysine diisocyanate methyl ester, trimethylhexamethylene diisocyanate; Polyisocyanate such as polyol adduct such as trimethylolpropane adduct and hexanetriol adduct Examples thereof include blocks. Examples of the blocking agent for blocking include, for example,
Oximes such as acetoxime and butanone oxime; phenols such as phenol and ethyl acetoacetate; enols; alcohols such as di-n-butylamine, 2,2,2-trifluoroethanol, N, N-dimethylhydrazine and amines; Basic nitrogen-containing compounds such as N, N-diethylhydroxylamine, 3-hydroxypyridine, 3-methyl-1-phenyl-2-pyrazolin-5-one and 3-methyl-2-pyrazolin-5-one; caprolactam; Acetohydroxamic acid; p-toluenesulfinic acid and the like can be mentioned.

In the above aqueous coating composition, the amount of the curing agent used is preferably 20 to 100 parts by weight based on 100 parts by weight of the total solid content of the contained resin. If it is less than 20 parts by weight, the curability will be insufficient, and if it exceeds 100 parts by weight, the cured coating film will be too hard and brittle. More preferably, it is 25 to 70 parts by weight.

By adding a polymer thickener to the water-based coating composition of the present invention, a water-based coating composition (II) which can secure better dispersion stability and workability can be obtained. it can. As the polymer thickener, for example,
Examples thereof include acrylic resin particles. Workability can be improved by adding the acrylic resin particles. The amount of the acrylic resin particles used is preferably 60% by weight or less with respect to the content of the resin solid content. 60
If the content is more than weight%, the smoothness of the obtained coating film is deteriorated.

A pigment may be added to the aqueous coating composition and the aqueous coating composition (II) of the present invention to prepare a pigment-containing aqueous coating composition. Examples of the pigment include titanium dioxide, graphite, chromium oxide, iron oxide, graphite,
Coloring pigments such as carbon black, phthalocyanine pigments, quinacridone; calcium carbonate, magnesium carbonate,
Examples include extender pigments such as barium sulfate, silicates, aluminum hydrates and calcium sulfate. When the pigment-containing water-based coating composition is used as an intermediate coating composition, it is desirable to use an inorganic pigment such as barium sulfate, calcium carbonate, clay or titanium oxide as a coloring pigment in a part of the pigment.

Further, as the above-mentioned pigment, a bright pigment can be mentioned. By using a bright pigment,
The pigment-containing aqueous coating composition can be made into an aqueous metallic coating composition. As the bright pigment, for example,
Aluminum foil, mica, tin foil, gold foil, metallic titanium foil,
Nickel foil etc. can be mentioned. The addition amount of the bright pigment is preferably 5 to 60 parts by weight based on 100 parts by weight of the total solid content of the contained resin. The above aqueous metallic coating composition can be suitably used as a coating for base coat.

The aqueous coating composition, aqueous coating composition (II) and pigment-containing aqueous coating composition of the present invention may further contain a defoaming agent, a dispersant, a surface modifier, a curing catalyst and the like as other additives. It can be added. Examples of the above-mentioned defoaming agent include a silicon-based defoaming agent and an acrylic defoaming agent.

Examples of the surface conditioner include a silicon type surface conditioner, an acrylic surface conditioner, and a fluorine type surface conditioner.

Examples of the curing catalyst include phosphoric acid curing catalysts, onium salt curing catalysts and the like.

The aqueous coating composition, the aqueous coating composition (II) and the pigment-containing aqueous coating composition of the present invention may be an aqueous solid coating composition having a high solid content. The water-based coating composition, the water-based coating composition (II), and the pigment-containing water-based coating composition of the present invention are water-based coating compositions using water, preferably deionized water as a medium. Organic solvents may be used. Examples of the organic solvent include ether alcohols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and ethylene glycol monobutyl ether;
Examples thereof include alcohol-based ones such as methanol, ethanol, isopropanol, n-butanol, sec-butanol, and t-butanol; ester-based ones; ketone-based ones.

In the present invention, the above aqueous coating composition,
The water-based coating composition (II) and the pigment-containing water-based coating composition are
Spray coating, brush coating, dip coating, roll coating,
It can be painted by flow coating. In this case, as a coating method for coating the above pigment-containing aqueous coating composition on an article to be coated, an ordinary method may be used, but (I) an undercoat coating film on the article to be coated and, if necessary, an intermediate coating film Or (II) applying the pigment-containing aqueous coating composition on the formed coating film, (III) without curing the applied pigment-containing aqueous coating composition, or
After curing, a step of applying a clear coat coating composition thereon, (IV) both of the applied pigment-containing aqueous coating composition and the clear coat coating composition, or the applied clear coating A method of coating by a so-called 2 coat 1 bake method or a 2 coat 2 bake method can be adopted in the step of curing only the coating composition for coating.

The clear coat coating composition used in combination with the pigment-containing aqueous coating composition of the present invention may be one using an aminoplast curing agent such as a melamine resin. It may not be used. Such things include, for example,
Examples thereof include clear coat coating compositions having both a carboxyl group-containing resin and an epoxy group-containing resin. Further, it may be composed of a half-esterified copolymer or an epoxy group-containing acrylic resin, and its coating material may be in the form of powder.

The aqueous coating composition, the aqueous coating composition (II) and the pigment-containing aqueous coating composition of the present invention can be applied to various objects to be coated. The article to be coated is not particularly limited as long as it can be used by heating and curing the water-based coating composition of the present invention. For example, automobile parts such as automobile bodies, wheels and bumpers; Home appliances such as machines; building materials such as outer wall materials.

[0062]

EXAMPLES The present invention will be described in more detail below with reference to production examples and examples, but the present invention is not limited to these examples.

Production Example 1-1 A polyester resin reactor was charged with 613 parts by weight of 1,9-nonanediol, 114 parts by weight of trimethylolpropane, 105 parts by weight of adipic acid and 536 parts by weight of phthalic anhydride, and 30 parts by weight of xylene. Then, the temperature was raised and water generated by the reaction was removed while azeotropically boiling with xylene. The temperature was raised to 190 ° C. over about 2 hours from the start of refluxing, stirring and dehydration were continued until the acid value corresponding to the carboxylic acid became 85, and then cooled to 140 ° C. While maintaining this temperature, 205 parts by weight of Cardura EIO (versic acid glycidyl ester, manufactured by Shell Co.) was added dropwise over 30 minutes, and then stirring was continued for 2 hours to complete the reaction. Acid value 5mgKOH / g, hydroxyl value 120m
A polyester resin (a) having gKOH / g and a number average molecular weight of 2350 was obtained.

Production Examples 1-2 to 1-5 Polyester Resins Polyester resins (b) to (e) were obtained in the same manner as Production Example 1-1, except that the composition was as shown in Table 1. Molecular weight and acid value (mgK of the obtained polyester resins (a) to (e))
OH / g) and hydroxyl value (mgKOH / g) are shown in Table 2. In Table 1, ND is 1,9-nonanediol, and Epol is hydrogenated polyisoprene diol (molecular weight 186
0, average degree of polymerization 26, manufactured by Idemitsu Petrochemical Co., Ltd., HD is
1,6-hexanediol, TMP for trimethylolpropane, PE for pentaerythritol, PA
N is phthalic anhydride, ADA is adipic acid, Ca
E10 indicates the Curdula E10, respectively.

[0065]

[Table 1]

[0066]

[Table 2]

Example 1-1 Polyester Graft Ac
In a ril resin and its aqueous dispersion reactor, 400 parts by weight of Solvesso-150 (hereinafter referred to as "S-150") (manufactured by Shoei Chemical Industry Co., Ltd.), 200 parts by weight of methyl isobutyl ketone (MIBK) and Production Example 1 were obtained. 200 parts by weight of the obtained polyester resin (a) was charged, and under stirring at 100 ° C., 166 parts by weight of hydroxyethyl acrylate (HEA) and methacrylic acid (MAA).
61 parts by weight, ethylhexyl methacrylate (EHM
A) A monomer mixture consisting of 520 parts by weight and styrene (ST) 53 parts by weight, and Kayaester O (t-butylperoxy-2-ethylhexanoate, manufactured by Kayaku Akzo).
10 parts by weight was added dropwise at a constant rate in 3 hours. After 30 minutes, 50 parts by weight of S-150 and 4 parts by weight of Kayaester O were further added dropwise over 30 minutes, and the mixture was further reacted at that temperature for 1 hour to give an acid value of 41 mgKOH / g and a hydroxyl value of 96 mgKOH /.
An ester-acrylic resin mixture having a weight average molecular weight of 10,000 was obtained. This ester-acrylic resin mixture was heated to 140 ° C. under stirring, and transesterified at that temperature for 4 hours to give an acid value of 41 mg KOH / g and a hydroxyl value of 96 mg.
A polyester-grafted acrylic resin having KOH / g and a number average molecular weight of 10,000 (hereinafter referred to as "polyester acrylic resin [1]") was obtained. The obtained polyester acrylic resin [1] was heated and stirred at 65 ° C., and 90 parts by weight of dimethanolamine and 3569 of deionized water were added thereto.
By adding parts by weight, the mixture was water-solubilized to obtain a viscous water dispersion having a milky color. The solid content of the obtained aqueous dispersion was 20%.

This aqueous dispersion was mixed with a B-type viscometer at 6 rp.
Diluted with deionized water to 1000 cps m. The yield value was 80 dyne / cm ² as determined by Casson plot using an E-type viscometer. It was 120 nm when the particle size was measured by the light scattering method. Also,
After the dilution, the mixture was allowed to stand at 40 ° C. for 10 days, and the dispersion state was visually evaluated. A uniform dispersed state was obtained both immediately after the dilution and immediately after the storage test.

Examples 1-2 to 1-5 polyester gras
Except that the shift acrylic resins and aqueous dispersion Table 3 formulations, those polyester-grafted acrylic resin (following these examples 1-2～1-5 in the same manner as in Example 1-1, respectively " Polyester acrylic resin [2] to [5] ") and its aqueous dispersion were obtained. Obtained polyester acrylic resin [2]
The characteristics of [5] are shown in Table 3. In Table 3, LMA represents lauryl methacrylate and NBMA represents n-butyl methacrylate.

Comparative Example 1-1 Polyester Blend Ac
400 parts by weight of S-150 and 200 parts of MIBK in a reactor of the ril resin and its water dispersion.
10 parts by weight of Kayaester O and a monomer mixture consisting of 166 parts by weight of hydroxyethyl acrylate, 61 parts by weight of methacrylic acid, 520 parts by weight of ethylhexyl methacrylate, and 53 parts by weight of styrene under a condition of 100 parts by weight with stirring. The mixture was added dropwise at a constant rate and further reacted at that temperature for 1 hour to obtain an acrylic resin having an acid value of 50 mgKOH / g, a hydroxyl value of 100 mgKOH / g and a number average molecular weight of 10,000. In addition, Production Example 1-
200 parts by weight of the polyester resin (d) obtained in Example 4 was added, and the mixture was stirred at 80 ° C. for 1 hour to obtain a polyester blend acrylic resin having an acid value of 41 mgKOH / g, a hydroxyl value of 96 mgKOH / g, and a number average molecular weight of 10000. Polyester acrylic resin [6] was obtained by heating and stirring the obtained polyester acrylic resin [6] at 65 ° C. and adding 90 parts by weight of dimethanolamine and 3569 parts by weight of deionized water to solubilize it. Thus, an emulsion-colored and viscous water dispersion was obtained, and the solid content of the obtained water dispersion was 20%.

This aqueous dispersion was mixed with a B-type viscometer at 6 rp.
Diluted with deionized water to 1000 cps m. The yield value was determined by Casson plot using an E-type viscometer and found to be 10 dyne / cm ² . After dilution, the mixture was allowed to stand at 40 ° C. for 10 days, and the dispersion state was visually evaluated. It was in a uniform dispersion state immediately after dilution, but separated immediately after the storage test.

Comparative Examples 1-2 to 1-4 Polyester blur
And acrylic resin and water dispersion thereof. Polyester blend acrylic resin of Comparative Examples 1-2 to 1-4 (hereinafter, these are respectively "Polyester acrylic resin [7] ~

[9] ") and an aqueous dispersion thereof were obtained. Obtained polyester acrylic resin [7]
~

The properties of [9] are shown in Table 4.

Comparative Examples 1-5 and 1-6 Polyester Gra
Except that the shift acrylic resin and blended in the aqueous dispersion Table 4, in the same manner as in Comparative Example 1-1, these things polyester graft acrylic resin of Comparative Example 1-5 and 1-6 (hereinafter, respectively "Polyester acrylic resin [10], [11]") and its aqueous dispersion were obtained. The properties of the obtained polyester acrylic resins [10] and [11] are shown in Table 4.

[0074]

[Table 3]

[0075]

[Table 4]

Examples 1-6 Water-dispersible resin composition and its composition
Cymel 212 (C-212) (Mitsui Toatsu Co., Ltd.) were uniformly mixed was added 30 parts by weight aqueous dispersion 369 parts by weight obtained in the aqueous dispersion in Example 1-1. Then, 4 parts by weight of paratoluenesulfonic acid (40% ethanol solution) was added and mixed uniformly, and then diluted with deionized water so that 1000 cps was obtained at 6 rpm using a B type viscometer. The solid content of this product was 23%. In addition, the yield value was determined by Casson plot using an E-type viscometer and found to be 70 dyne.
/ Cm ² . The solution obtained is cast to form a film thickness of 30.
It is applied to the intermediate coating test plate so that it becomes
After baking for a minute, a transparent coating film was obtained. The obtained coating film was evaluated by the following methods. Table 5 shows the results. In addition, the dispersion state after standing at 40 ° C. for 10 days after dilution was visually determined. Immediately after the dilution and after the storage test, it was in a uniformly dispersed state.

Evaluation method 1. Solvent resistance Six drops of butyldiglycol (BDG) were dropped on the obtained coated surface and left for 24 hours. As a result, no change was observed on the coated surface and good solvent resistance was exhibited. The case where there is no abnormality in the coating film was evaluated as ◯, and the case where there was blur or discoloration was evaluated as x. 2. Water resistance The cured coating film was immersed in warm water at 40 ° C. for 10 days. The water resistance of the coated surface was evaluated by observing the change of the coated surface. As a result, no change in the coated surface was observed and good water resistance was exhibited. The case where there is no abnormality in the coating film was evaluated as ◯, and the case where there was blur or discoloration was evaluated as x.

Examples 1-7 to 1-10, Comparative Examples 1-7 to
1-12 Water-dispersible resin composition and its water dispersion Example 1-6 except that the formulations shown in Tables 5 and 6 were used.
An aqueous dispersion was obtained in the same manner as above, and the dispersion stability, yield value, coating film appearance, solvent resistance and water resistance were evaluated. The results are shown in Tables 5 and 6. The solid content of the obtained water-dispersible resin composition is also shown in Tables 5 and 6.

[0079]

[Table 5]

[0080]

[Table 6]

Production Examples 2-1, 2-2 Polyester Gra
Except that the shift acrylic resin and formulation shown in the aqueous dispersion solution Table 7, the polyester-grafted acrylic resin of Preparation 2-1 in the same manner as in Example 1-1, polyester-grafted acrylic resin of Preparation 2-2 (Hereinafter, these are respectively referred to as “polyester acrylic resin [12] and polyester acrylic resin [1
3] ”) and its aqueous dispersion. Table 7 shows the properties of the obtained polyester acrylic resin [12], polyester acrylic resin [13], and an aqueous dispersion thereof. In Table 7, LMA represents lauryl methacrylate.

Production Example 2-3 Polyester Blend Ac
400 parts by weight of S-150 and 200 parts of MIBK in a reactor of ril resin and its aqueous dispersion solution.
10 parts by weight of Kayaester O was added to a monomer mixture consisting of 166 parts by weight of hydroxyethyl acrylate, 61 parts by weight of methacrylic acid, 520 parts by weight of ethylhexyl methacrylate and 53 parts by weight of styrene under a condition of 100 ° C. under stirring. Was added dropwise at a constant rate over 3 hours.
Thereafter, 50 parts by weight of S-150 and 4 parts by weight of Kayaester O were added dropwise over 30 minutes, and the mixture was reacted at that temperature for 1 hour to give an acid value of 50 mgKOH / g and a hydroxyl value of 100.
An acrylic resin having mgKOH / g and a number average molecular weight of 10,000 was obtained. In addition to the obtained acrylic resin, Production Example 1-
Add 200 parts by weight of the polyester resin (a) obtained in 1 to 8
Stir for 1 hour at 0 ° C. and blend with polyester blend acrylic resin (hereinafter
4] ”). Table 7 shows the characteristics of this product. The obtained polyester acrylic resin [14] was mixed with 65
The mixture was heated and stirred at 0 ° C., and 90 parts by weight of dimethanolamine and 2274 parts by weight of deionized water were added thereto to be water-solubilized to obtain a milky viscous aqueous dispersion solution. The solid content of the obtained aqueous dispersion solution was 25%.

[0083]

[Table 7]

Production Example 2-4 In a resin reactor for dispersion , diethylene glycol monobutyl ether (B
DG) 400 parts by weight are charged, and 100 parts by weight of styrene, 172 parts by weight of methyl methacrylate, 230 parts by weight of lauryl acrylate, 219 parts by weight of methyl acrylate, and Praxel FM-1 (manufactured by Daicel Chemical Industries, Ltd.) under stirring at 100 ° C. ) 3 parts of a monomer mixture consisting of 218 parts by weight, 61 parts by weight of methacrylic acid and 10 parts by weight of Kayaester O.
After 30 minutes, 50 parts by weight of BDG and 3 parts by weight of Kayaester O are added dropwise over 30 minutes, and the mixture is further reacted at that temperature for 1 hour to give an acid value of 40 mgKOH / g, a hydroxyl value of 50 mgKOH / g, and a number average. An acrylic resin having a molecular weight of 17,000 (hereinafter referred to as "dispersion resin") was obtained. The resulting dispersion resin was heated and stirred at 85 ° C., and 87 parts by weight of triethylamine and 2952 parts by weight of deionized water were added thereto to be water-solubilized to obtain a transparent and viscous aqueous solution. The solid content of the obtained aqueous solution was 22%.

Production Example 2-5 A resin reactor for thickening was charged with 180 parts by weight of deionized water, 10 parts by weight of styrene, 0.7 parts by weight of methacrylic acid and 0.7 parts by weight of dimethanolamine, and heated to 83 ° C. Warmed. Next, 0.5 part by weight of 4,4'-azobis-4-cyanovaleric acid was neutralized with 0.87 part by weight of dimethylethanolamine, and dissolved in 5 parts by weight of deionized water was added dropwise over 20 minutes. did. Furthermore, a mixture of 84.3 parts by weight of styrene, 5 parts by weight of methacrylic acid and 5 parts by weight of dimethylethanolamine, and 0.5 parts by weight of 4,4'-azobis-4-cyanovaleric acid were added to 0.27 parts of dimethylethanolamine. What was neutralized with 20 parts by weight and dissolved in 40 parts by weight of deionized water was added dropwise over 2 hours, and stirring was continued for 1 hour to obtain a white emulsion (hereinafter referred to as "thickening resin"). It was This product had a solid content of 30% and a particle size of 330 nm (laser light scattering method).

Production Example 2-6 Pigment Dispersion Paste (1) 186 parts by weight of the polyester acrylic resin [12] obtained in Production Example 2-2, 20 parts by weight of blue A3RN ( (Ciba Geigy Co., Ltd., blue pigment) and 15 parts by weight of deionized water were weighed, 480 cc of glass beads were added, and the mixture was premixed with a stirrer, and then mixed and dispersed with a paint conditioner for 2 hours to prepare a pigment dispersion paste (1). Obtained.

Examples 2-1 to 2-4, Comparative examples 2-1 and 2
-2 By the formulation shown in Table 8, water-based metallic base paints (i) to (vi) were prepared. However, the polyester acrylic resin [1] was prepared by adding 2274 parts by weight of deionized water and used as a solid content of 25%. Aluminum pigment (aluminum paste NW-91-2061, aluminum metal pigment 62%, manufactured by Toyo Aluminum Co., Ltd.) is a resin for dispersion in advance,
If necessary, it was uniformly mixed with the pigment dispersion paste (1). The polyester acrylic resin component and the curing agent were also mixed in advance, particularly when a melamine resin was used as the curing agent, they were mixed and solubilized when solubilizing the polyester acrylic resin, and then uniformly mixed with the dispersion paste. Further, additives and thickeners were added, and an aqueous metallic base paint was prepared by using a stirrer at room temperature. Further, the aluminum pigment is 11.4-12.100 parts by weight of the resin solid content.
It was blended so as to be 5 parts by weight. C-212 in Table 8
Is a melamine resin hardener manufactured by Mitsui Cytec Co., Ltd.
Reference numeral 116 represents a block isocyanate curing agent manufactured by Sumitomo Bayer Co., Ltd., respectively. BYK represents a silicon-based defoaming agent manufactured by Big Chemie Japan. PWC represents the pigment content (% by weight).

[0088]

[Table 8]

Production Example 2-7 Clear Paint (C-1) 900 parts by weight of xylene was charged into a reaction vessel and heated to 100 ° C., and then 12 parts by weight of methacrylic acid and styrene 264.
Parts by weight, 264 parts by weight of methyl methacrylate, 360 parts by weight of n-butyl acrylate, 100 parts by weight of 2-hydroxyethyl acrylate, and 10 parts by weight of azobisbutyronitrile are added dropwise at a constant rate over 3 hours, and further. A solution of 3 parts by weight of azobisbutyronitrile and 100 parts by weight of xylene was added dropwise over 30 minutes. The reaction was further continued for 2 hours to obtain an acrylic resin solution having a nonvolatile content of 50% and a number average molecular weight of 8000. To 100 parts by weight of this acrylic resin, 36 parts by weight of U-Van 20SE-60 (manufactured by Mitsui Toatsu Chemicals, Inc.) and 0.5 parts by weight of Modaflow (manufactured by Monsanto Co., Ltd.) were mixed to prepare a clear coating (C-1).

Examples 2-5 to 2-8, Comparative examples 2-3 and 2
-4 The obtained water-based metallic base coating materials (i), (ii),
(Iv) to (vi) NACURE 5225 (amine-blocked acid catalyst, King Industries)
Inc. After adding 1 part by weight, Ford Cup N
o. The viscosity was adjusted by diluting with deionized water so as to obtain 60 seconds at 4. Aqueous metallic base paint (iii) is NAC
The viscosity was similarly adjusted without adding URE5225. The water-based metallic base paints (i) to (vi) whose viscosities were adjusted in this way were respectively spray-coated on a steel plate which had been previously subjected to intermediate coating to give a dry film thickness of 10 to 50 μm.
And was dried at 80 ° C. for 10 minutes. Then, clear coating material (C-1) was applied so that the dry film thickness was 40 μm. After setting for 5 minutes, the base coat and the clear coat were simultaneously baked at 140 ° C. for 30 minutes.

Examples 2-5 to 2-8, Comparative examples 2-3 and 2
The finished appearance, water resistance and solvent resistance of each of the coating films of No. 4 were evaluated by the following methods. The results are shown in Table 9. The coating conditions were 25 ° C. and two levels of humidity of 65% and 85%. The storage stability of each of the aqueous metallic base paints used was also evaluated by the following method. The results are also shown in Table 9.

Evaluation method 1. Sagging Limit Film Thickness The maximum sagging film thickness without any sagging coating defects in a coating film that was slope-coated so that the thin film portion had a thickness of 10 μm and the thick film portion had a thickness of 50 μm. A sagging limit film thickness of 25 μm or more was judged as acceptable. The coating films of Examples 2-5 to 2-8 all passed. 2. Critical Film Thickness The maximum film thickness without any film defect of the film in a coating film which was obliquely coated so as to be 10 μm in the thin film portion and 50 μm in the thick film portion was defined as the critical film thickness. A film thickness of at least 25 μm was considered to be acceptable. The coating films of Examples 2-5 to 2-8 all passed. 3. Appearance of coating film The appearance of the coating film was judged by visual observation and a flip value measured by a metallic aviation tester. The evaluation criteria are as follows. ◯: Good (the orientation of aluminum is good, and the flip value measured by a metallic aviation tester is 30 or more) Δ: Somewhat inferior (a little inferior aluminum composition, flip value is less than 30 25 or more) ×: Poor (of aluminum 3. The orientation is disturbed and the flip value is less than 25) 4. Solvent resistance A predetermined amount of the cured coating film was extracted using a Soxhlet extractor under the condition of refluxing the acetone solution for 1 hour to extract the soluble portion. The case where the extraction rate was less than 5% was regarded as a pass (◯), and the case where the extraction rate was more than 5% was regarded as a failure (x). 5. Water resistance The water resistance of the coated surface was evaluated by immersing the cured coating film in warm water at 40 ° C. for 10 days and observing changes in the coated surface. When there was no abnormality, it was marked with ◯, and when it was glossy or discolored, it was marked with x. 6. Storage stability Initial stability immediately after dilution, and the resin after dilution at 40 ° C
The stability after aging when allowed to stand for 10 days was visually evaluated.

[0093]

[Table 9]

Examples 2-9 to 2-12, Comparative Examples 2-5,
2-6 Examples 2-5 except that the formulation shown in Table 10 was used.
Water-based metallic base paint (vi
i) to (xii) were created.

[0095]

[Table 10]

Production Example 2-8 Clear Paint (C-2) 1. Production of acrylic resin varnish After charging 500 parts by weight of butyl acetate into a reaction vessel and heating to 125 ° C., 50 parts by weight of styrene, 400 parts by weight of glycidyl methacrylate, 26.4 parts by weight of methyl methacrylate, 200 parts by weight of 2-ethylhexyl acrylate. Two
-Hydroxyethyl acrylate 350 parts by weight and t-
A mixed solution consisting of 70 parts by weight of butylperoxy-2-ethylhexanoate (Kayaester O) was added dropwise at a constant rate over 3 hours. After keeping the temperature at 125 ° C for 30 minutes after the dropping,
A solution containing 10 parts by weight of Kayaester O and 250 parts by weight of xylene was added dropwise over 80 minutes. 2 more after dropping
The reaction was continued at 125 ° C. for an hour to obtain an acrylic resin varnish having a nonvolatile content of 59% and a number average molecular weight of 4000.

2. Production of Polymer Containing Anhydrous Carboxyl Group After adding 80 parts by weight of xylene to a reaction vessel and heating to 115 ° C., 25 parts by weight of styrene, 21 parts by weight of N-butyl acrylate, 95 parts by weight of n-butyl methacrylate, 2
A mixed solution consisting of 34 parts by weight of ethylhexyl acrylate, 50 parts by weight of itaconic anhydride, 100 parts by weight of propylene glycol monomethyl ether acetate, and 10 parts by weight of Kayaester O was added dropwise at a constant rate over 3 hours.
After the dropwise addition was completed, stirring was continued for 2 hours at 115 ° C. to obtain an anhydrous carboxyl group-containing polymer having a nonvolatile content of 53% and a number average molecular weight of 5500.

3. Production of half-esterified polymer 1. Anhydrous carboxyl group-containing polymer 385 obtained in
To 35 parts by weight of butyl acetate, 1.35 parts by weight of triethylamine and 18.2 parts by weight of methanol were added, and the mixture was reacted at 40 ° C. for 12 hours. IR absorption of acid anhydride group (1785 cm ⁻¹ ) was complete. After disappearance, it was confirmed that a half-esterified polymer was obtained.

4. Manufacturing of clear paint (C-2) 1. 2. 100 parts by weight of the acrylic resin varnish obtained in 3. 133 parts by weight of the half-esterified polymer obtained in 1., 0.3 parts by weight of tetrabutylammonium bromide, 1.2 parts by weight of Tinuvin-900 (benzotriazole-based UV absorber manufactured by Ciba-Geigy), Sanol LS-292 (manufactured by Sankyo Co., Ltd.) 0.6 parts by weight of a hindered amine-based light stabilizer was stirred with a laboratory stirrer to produce a clear coating (C-2). This was diluted to a paint viscosity with a thinner composed of butyl acetate / xylene = 1/1.

Examples 2-13 and 2-14, Comparative Example 2-7 The water-based metallic base paints (v) obtained in Example 2-9.
After adding 1 part by weight of NACURE 5225 (amine-blocked acid catalyst, manufactured by King Industries Inc.) to ii), Ford Cup No. 4 in 6
The viscosity was adjusted by diluting with deionized water so as to be 0 second. Aqueous metallic base paints obtained in Examples 2-10 (v
iii) and the water-based metallic base paints (xi) obtained in Comparative Examples 2-5 were similarly viscosity-adjusted without adding NACURE5225. Aqueous metallic base paint (vii), (vii) whose viscosity is adjusted in this way
Each of i) and (xi) was applied by spray coating on a steel sheet that had been previously subjected to intermediate coating so that the dry film thickness was 10 to 50 μm, and dried at 80 ° C. for 10 minutes. Then, apply clear coating (C-2) to a dry film thickness of 40 μm.
It was painted to be m. After setting for 5 minutes, the base coat and the clear coat were simultaneously baked at 140 ° C. for 30 minutes.

Examples 2-13 and 2-14, Comparative Example 2-7
The finished appearance, water resistance, and solvent resistance of each coating film were evaluated in the same manner as in Example 2-5. The results are shown in Table 11.
The coating conditions were 25 ° C. and two levels of humidity of 65% and 85%. The storage stability of each of the aqueous metallic base coatings used was also evaluated in the same manner as in Example 2-5. The results are also shown in Table 11.

Production Example 2-9 Powder Clear Paint 1. Production of acrylic resin varnish A reactor was charged with 630 parts by weight of xylene, and the temperature was raised to 130 ° C. Using a dropping funnel, 200 parts by weight of styrene, 450 parts by weight of glycidyl methacrylate, 270 parts by weight of methyl methacrylate, isobutyl methacrylate 8
A mixed solution of 0 parts by weight and 75 parts by weight of Kayaester O was added dropwise at a constant rate over 3 hours. After maintaining for 30 minutes after the completion of dropping, 1 part by weight of Kayaester O and 7 parts of xylene were further added.
A solution consisting of 0 parts by weight was added dropwise over 30 minutes. After the completion of the dropwise addition, the reaction was further continued at 130 ° C. for 1 hour, and xylene was removed by distillation under reduced pressure to obtain an acrylic resin varnish.

2. Manufacture of powder clear paint 70 parts by weight of the obtained acrylic resin varnish, 19.1 parts by weight of decanedicarboxylic acid, 0.11 part by weight of CF-1056 (manufactured by Toray Dow Corning Silicone Co., Ltd.), benzoin
89 parts by weight were dry mixed with a Henschel mixer (manufactured by Mitsui Miike Seisakusho Co., Ltd.), and then Cokneader PR-46.
(Manufactured by Buss, Switzerland), dissolved and dispersed at a temperature of 100 ° C., cooled, pulverized with a hammer mill, and classified with a wire mesh of 150 mesh to obtain a powder acrylic clear paint.

Examples 2-15, 2-16, Comparative Example 2-8 Obtained Examples 2-11, 2-12 and the aqueous metallic base coating materials (ix), (x) obtained in Comparative Example 2-6. ),
(Xii) to NACURE 5225 (amine-blocked acid catalyst, King Industries, respectively).
Inc. (Ford Cup No. 1). It was diluted with deionized water at 4 to 60 seconds, spray-coated on a steel sheet that had been previously coated with intermediate coating so that the dry film thickness was 10 to 50 μm, and dried at 80 ° C. for 10 minutes. Then dry the powder clear paint to a dry film thickness of 40μ.
Then, the base coat and the clear coat were simultaneously baked at 150 ° C. for 30 minutes.

Examples 2-15 and 2-16, Comparative Example 2-8
The finished appearance, water resistance, and solvent resistance of each coating film were evaluated in the same manner as in Example 2-5. The results are shown in Table 11.
The coating conditions were 25 ° C. and two levels of humidity of 65% and 85%. The storage stability of each of the aqueous metallic base coatings used was also evaluated in the same manner as in Example 2-5. The results are also shown in Table 11.

[0106]

[Table 11]

Production Example 2-10 Pigment Dispersion Paste (2) Example 1 was placed in a 3.0 liter hermetically sealable stainless steel container.
-1 polyester acrylic resin [1] solid content 25%
350 parts by weight and 175 parts by weight of blue A3RN (manufactured by Japan Ciba Geigy Co., Ltd., blue pigment) were weighed, 1000 cc of glass beads were added, and the mixture was premixed with a stirrer, and then mixed and dispersed for 2 hours with a paint conditioner. To obtain a pigment dispersion paste (2).

Examples 2-17 to 2-19 and Comparative Example 2-9 Aqueous solid base coatings [I] to [IV] were prepared at a room temperature using a stirrer with the formulations shown in Table 12.

[0109]

[Table 12]

The obtained aqueous solid base coatings [I], [II] of Examples 2-17, 2-18 and Comparative Example 2-9,
In [IV], NACURE 5225 (amine-blocked acid catalyst, King Industries
Inc. After adding 1 part by weight, Ford Cup N
o. The viscosity was adjusted by diluting with deionized water so that the viscosity was 4 seconds and 60 seconds. The aqueous solid base coating [III] obtained in Example 2-19 was similarly viscosity-adjusted without adding NACURE5225. Each of the aqueous solid base paints [I] to [IV] whose viscosity is adjusted in this way
Is spray-coated on a steel plate that has been previously coated with an intermediate coat so that the dry film thickness is 10 to 50 μm,
Dry for 0 minutes. Next, the clear coating material (C-1) was applied so that the dry film thickness was 40 μm. After setting for 5 minutes, apply the base coat and clear coat at the same time.
Baking at 40 ° C. for 30 minutes, Examples 2-17 to 2-19,
The water resistance and solvent resistance of each coating film of Comparative Example 2-9 was measured in Example 2
It evaluated similarly to -5. The appearance of each coating film was evaluated by examining the gloss by the following method. The results are shown in Table 13.
The coating conditions were 25 ° C. and two levels of humidity of 65% and 85%. The storage stability of each of the aqueous metallic base coatings used was also evaluated in the same manner as in Example 2-5. The results are also shown in Table 13.

Evaluation method 1. Gloss (60 ° gloss) The appearance of the coated surface was evaluated by measuring the gloss of the coated surface using a Suga Test Instruments digital variable angle gloss meter. The evaluation criteria are as follows. A: 90 or more O: 85 or more and less than 90 B: 80 to 85 X: 80 or less

[0112]

[Table 13]

[0113]

The thermosetting water-based resin composition used in the present invention has a structure in which a water-insoluble polyester resin is grafted onto a water-soluble acrylic resin. When it is placed in a portion, it becomes a shell, and when the polyester resin is placed inside, it becomes a core particle. Therefore, the compatibility between the resins is improved and the dispersion stability is greatly improved. In addition, since the particles have a small particle size, the structural viscosity increases due to the interparticle interaction resulting from the interaction in the hydrophobic portion of the shell, and therefore,
The sagging property is improved even in high humidity.

According to the production method of the present invention, when grafting polymers with each other, they can be simply carried out by simply heating them, and existing facilities can be utilized. Very convenient for production.

The aqueous coating composition of the present invention has improved stability because the thermosetting aqueous resin composition used as a binder has excellent compatibility with other components such as a curing agent. . Further, since the polyester resin in the thermosetting aqueous resin composition is hydrophobic, water is released from the coating film well, and so-called water releasability is good. Therefore, the armpit phenomenon due to bumping of water during curing is extremely reduced,
It also improves the workability in painting work. As a result, the conditions for good workability are extremely wide. Furthermore, between resin and resin
The improved compatibility between the curing agents also improves the uniformity of the coating film,
As a result, the transparency, smoothness, chemical resistance, water resistance and mechanical strength of the coating film are also improved.

Claims (19)

[Claims] 1. A film formation obtained by copolymerizing an ethylenic monomer having a saturated hydrocarbon group having 6 to 18 carbon atoms, a hydroxyl group-containing ethylenic monomer, an acidic group-containing ethylenic monomer and other ethylenic monomers. The polymer (A) is 50 to 90% by weight, and the polyester resin (B) having a hydroxyl group at the terminal is 50 to 10% by weight, and the total amount of the (A) and the (B) is 100% by weight.
And the polyester resin (B) is grafted to the film-forming polymer (A) by a transesterification reaction,
A thermosetting aqueous resin composition, characterized in that at least a part of the acidic groups in the film-forming polymer (A) is neutralized with a base (C). 2. The film-forming polymer (A) has a number average molecular weight of 5,000 to 100,000 and an acid value of 10 to 100.
mgKOH / g, with a hydroxyl value of 50 to 200 mgK
The thermosetting aqueous resin composition according to claim 1, which is OH / g. 3. The film-forming polymer (A) has 6 to 1 carbon atoms.
The thermosetting aqueous resin composition according to claim 1 or 2, wherein the content of the ethylenic monomer having a saturated hydrocarbon group of 8 is 30 to 80% by weight. 4. A molar ratio of at least a part of the acidic groups in the film-forming polymer (A) to the acidic groups is 0.4 to 2.0.
The thermosetting aqueous resin composition according to claim 1, 2 or 3, which is neutralized with an amount of amine. 5. The polyester resin (B) having a hydroxyl group at the terminal has a number average molecular weight of 500 to 10,000,
An acid value of less than 15 mg KOH / g.
The thermosetting aqueous resin composition according to 2, 3, or 4. 6. A coating film obtained by copolymerizing an ethylenic monomer having a saturated hydrocarbon group having 6 to 18 carbon atoms, a hydroxyl group-containing ethylenic monomer, an acidic group-containing ethylenic monomer and other ethylenic monomers. The polymer (A) 50 to 90% by weight and the polyester resin (B) 50 to 10% by weight having a hydroxyl group at the terminal are added in such a proportion that the total of the (A) and the (B) is 100% by weight, A thermosetting aqueous resin composition characterized in that a transesterification reaction is carried out at 130 to 200 ° C., and then at least a part of the acidic groups contained in the film-forming polymer (A) is neutralized with a base (C). Method of manufacturing things. 7. A film formation obtained by copolymerizing an ethylenic monomer having a saturated hydrocarbon group having 6 to 18 carbon atoms, a hydroxyl group-containing ethylenic monomer, an acidic group-containing ethylenic monomer and other ethylenic monomers. The polymer (A) is 50 to 90% by weight, and the polyester resin (B) having a hydroxyl group at the terminal is 50 to 10% by weight, and the total amount of the (A) and the (B) is 100% by weight.
And the film-forming polymer (A) and the polyester resin (B) are grafted by a transesterification reaction, and at least a part of the acidic groups in the film-forming polymer (A) is a base (C ) Is an emulsified aqueous resin aqueous dispersion of thermosetting aqueous resin composition particles neutralized by, wherein the thermosetting aqueous resin composition particles have the polyester resin (B) as a core, An aqueous resin aqueous dispersion having a structure having the film-forming polymer (A) as a shell. 8. A coating film obtained by copolymerizing an ethylenic monomer having a saturated hydrocarbon group having 6 to 18 carbon atoms, a hydroxyl group-containing ethylenic monomer, an acidic group-containing ethylenic monomer and other ethylenic monomers. The polymer (A) is 50 to 90% by weight, and the polyester resin (B) having a hydroxyl group at the terminal is 50 to 10% by weight, and the total amount of the (A) and the (B) is 100% by weight.
And the polyester resin (B) is grafted to the film-forming polymer (A) by a transesterification reaction,
And a thermosetting water-based resin composition obtained by neutralizing at least a part of the acidic groups in the film-forming polymer (A) with a base (C); and a curing agent. Stuff. 9. The aqueous coating composition according to claim 8, wherein the solid content ratio between the thermosetting aqueous resin composition and the curing agent is 100/20 to 100/100. 10. The curing agent is an amino resin.
An aqueous coating composition as described in the above. 11. The aqueous solution according to claim 8, wherein the thermosetting aqueous resin composition forms particles having a structure having a polyester resin (B) as a core and a film-forming polymer (A) as a shell. Coating composition. 12. An aqueous coating composition obtained by further adding a polymer thickener to the aqueous coating composition according to claim 8. 13. A pigment-containing aqueous coating composition obtained by further adding a pigment to the aqueous coating composition according to claim 8. 14. The aqueous coating composition according to claim 12,
Furthermore, a pigment-containing aqueous coating composition obtained by adding a pigment. 15. The pigment according to claim 13, which is a bright pigment.
The pigment-containing aqueous coating composition described. 16. The pigment is a bright pigment.
The pigment-containing aqueous coating composition described. 17. The pigment-containing water-based coating composition according to claim 13, wherein (I) a step of forming an undercoat coating film and, if necessary, an intermediate coating film on the article to be coated, (II) above the formed coating film. A step of applying at least one pigment-containing water-based coating composition selected from the group consisting of a composition and the pigment-containing water-based coating composition according to claim 14, (III) applying the pigment-containing water-based coating composition. Without curing or after curing, a step of applying a clear coat coating composition thereon, (IV) both the applied pigment-containing aqueous coating composition and the clear coat coating composition, Alternatively, a coating method comprising a step of curing only the applied clear coat coating composition. 18. A coated article obtained by coating the aqueous coating composition according to claim 8. 19. A coated article, which is coated by the coating method according to claim 17.