JP2001187859A - Coating resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide coating resin compositions which have good storage stability and excellent curability at low temperatures (<=80 deg.C) and are balanced with respect to various performances (adhesion, external appearance, weatherability, chemical resistance, solvent resistance and the like) and, in addition, excel in the weatherability and above all, one-pack type coating resin compositions. SOLUTION: The coating resin compositions comprises (A) an acrylic resin having a hydroxy group and an alicyclic epoxy group in the side chain, (B) an alicyclic epoxy resin having an epoxy equivalent weight of 100-1,000, (C) an organoalkoxy-silane compound having a glycidyl group and a hydrolyzable alkoxysilane group in the molecule, (D) an aluminum chelate compound, and (E) an acrylic resin having an alkoxysilane group in the molecule and a number average molecular weight of 2,000-100,000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for coatings having excellent low-temperature curability at 80.degree. C. or lower.

[0002]

2. Description of the Related Art Conventionally, a one-pack type coating resin excellent in curability at a low temperature (80 ° C. or lower) has been desired, and the following techniques have been proposed, but the storage stability has been proposed. In addition, none of them have curability and performances required for many paints in a well-balanced manner.

That is, in the case of a conventionally used curing system of an acrylic polyol having a hydroxyl group in a molecular side chain and a melamine resin or a blocked isocyanate, or an epoxy resin using a latent catalyst (curing agent), at least 120 ° C. Curing is the actual state, and at a curing temperature lower than that, a sufficient cross-linking density cannot be obtained, and coating film performance and the like cannot be expected. In order to cure at a temperature lower than that, it is necessary to increase the number of liquids, leaving many problems in workability. In addition, although the curability is good when polyisocyanate is used, there is a problem in the toxicity of isocyanate.

As a relatively recent technology, there has been disclosed an acrylic resin having an alkoxysilane group or an epoxy group in a side chain added with a metal chelate compound such as an aluminum chelate compound (Japanese Patent Publication No. 55-41712).
JP, JP-B-60-50223, JP-B-60-50
No. 50225, JP-B-61-23816, JP-B-61-23817, JP-A-64-75502
JP, JP-A-4-139281, JP-A 1-2
59071, JP-A-1-287177),
In these systems, the acrylic resin has an alkoxysilane group (or a hydrolyzed silanol group) in the side chain, which causes unreasonability and poor storage stability. In the case of low-temperature curing at 80 ° C. or lower, a two-pack type is adopted.
The curability at a low temperature of 0 ° C. or less was insufficient.

Furthermore, since the acrylic resin has an alkoxysilane group in the side chain, seeding (aggregation and the like) with the pigment is liable to occur, and only the surface of the coating film is dried and hardened preferentially when applied. Therefore, the solvent remains forever in the coating film, and the expected coating film performance cannot be obtained.) If the coating is performed at a high humidity or when dried at a low temperature, a problem occurs in that the coating film may be spotted. was there.

Further, Japanese Patent Application Laid-Open No. 62-119276 discloses an acrylic resin having an epoxy group or a hydroxyl group in a side chain and a bisphenol A type epoxy resin, a silane compound having an amino group or a glycidyl group, and an aluminum chelate compound. JP-A-2-73825 discloses a primer composition comprising (1) a metal chelate compound such as a hydroxyl group-containing acrylic resin, an alicyclic epoxy resin, a silane compound, and an aluminum chelate compound, and (2) A resin composition containing an (alicyclic) acrylic resin having an epoxy group and a hydroxyl group, a silane compound, and a metal chelate compound such as an aluminum chelate compound, and a method for curing the same are disclosed. However,
There is no description about using a silane compound having an alicyclic epoxy group and a glycidyl group in both the acrylic resin and the epoxy resin. In addition, Japanese Patent Application Laid-Open
JP 87942 discloses a one-pack composition comprising an acrylic resin having a hydroxyl group and an epoxy group in a side chain, various silane compounds, a curing catalyst such as an aluminum chelate compound, and an organic solvent.

[0007]

However, in these methods, the curability at a low temperature of 80 ° C. or less is insufficient, and furthermore, the occurrence of blemishes is extremely liable to occur. Achieving a well-balanced and high level of performance and paint appearance was still inadequate.

The present invention has been made in view of the background of the prior art,
Excellent storage stability, good curability at low temperature (80 ° C or lower), various properties of coating film (adhesion, appearance, weather resistance, chemical resistance,
Solvent resistance, etc.) and provide a coating resin composition having excellent weather resistance, especially a one-pack type coating resin composition.

[0009]

The present invention employs the following means in order to solve the above-mentioned problems. That is, the resin composition for a coating material of the present invention comprises an acrylic resin (A) having a hydroxyl group and an alicyclic epoxy group in a side chain.
An alicyclic epoxy resin (B) having an epoxy equivalent of 100 to 1000, an organoalkoxysilane compound (C) having a glycidyl group and a hydrolyzable alkoxysilane group in one molecule, and an aluminum chelate compound (D) And an acrylic resin (E) having an alkoxysilane group in the molecule and having a number average molecular weight of 2,000 to 100,000.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The object of the present invention is to provide the above-mentioned subject, that is, excellent curability at a low temperature (80 ° C. or less) with good storage stability,
Balanced coating film properties (adhesion, appearance, weather resistance, chemical resistance, solvent resistance, etc.) and further excellent weather resistance, especially one-pack type resin composition for coatings Thorough examination of the product, specific acrylic resin (A)
And a specific alicyclic epoxy resin (B), a specific organoalkoxysilane compound (C), an aluminum chelate compound (D), and a specific acrylic resin (E) different from A. When viewed as a composition, it has been surprisingly sought to solve such a problem at once.

In the present invention, the acrylic resin (A) having a hydroxyl group and an alicyclic epoxy group in the side chain is used when producing an acrylic resin. It can be produced by copolymerizing a monomer.

Such hydroxyl-containing unsaturated monomers include:
2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate,
1,4-dimethylolcyclohexane monoacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, monomethacrylate of 1,4-dimethylolcyclohexane, carbon of acrylic acid or methacrylic acid An adduct of a hydroxyalkyl ester having 2 to 8 atoms with a lactone such as ε-caprolactone or γ-valerolactone, monoalkylene or methacrylate of polyalkylene glycol (provided that the alkylene group has 1 to 4 carbon atoms) ) Can be used. These monomers may be used alone or as a mixture of two or more.

Among these monomers, those having a homopolymer having a glass transition temperature (Tg) of 0 ° C. or lower are preferably used. When Tg is 0 ° C. or lower, the curability of the coating tends to be improved, and the amount of the hydroxyl group-containing unsaturated monomer can be reduced, so that the amount of the hydroxyl group remaining unreacted can be reduced. It can be measured, and tends to improve chemical resistance such as water resistance and alcohol resistance.

Specific examples of the hydroxyl group-containing unsaturated monomer having a Tg of 0 ° C. or lower include 2-hydroxyethyl acrylate (Tg of homopolymer = −15 ° C.) and 2-hydroxypropyl acrylate (Tg = -45 ° C.), 4-hydroxybutyl acrylate (Tg = −80 ° C.), hydroxyalkyl ester of acrylic acid or methacrylic acid having 2 to 8 carbon atoms and ε-caprolactone or γ
-Adducts with lactones such as valerolactone (Tg =-
5 to -60 [deg.] C.). Such monomers may be used alone or as a mixture of two or more. In addition, more preferably, Tg is -30 ° C.
The following monomers are preferred. For example, when 4-hydroxybutyl acrylate (Tg = −80 ° C.) is copolymerized, the appearance of the coating film (gloss, sharpness, etc.) tends to be improved.

These monomers are copolymerized so that the acrylic resin has a hydroxyl value of preferably 0.5 to 80 mgKOH, more preferably 5 to 50 mgKOH. If the hydroxyl value is less than 0.5 mgKOH, the curability at low temperatures tends to be slightly slow, and the chemical resistance and weather resistance may deteriorate. When the hydroxyl value exceeds 80 mgKOH, when the thickness of the coating film is increased to about 100 μm at the time of drying at a low temperature, the coating film tends to generate a large amount of shrinkage, and a beautiful coated article may not be obtained. Next, examples of the unsaturated alicyclic epoxy group-containing unsaturated monomer include an unsaturated monomer having an oxirane group directly bonded to a cycloalkyl group such as 3,4-epoxycyclohexylmethyl acrylate and 3,4-epoxycyclohexylmethyl methacrylate. Dimers can be used. Such alicyclic epoxy group-containing unsaturated monomers may be used alone or as a mixture of two or more.

The alicyclic epoxy group-containing unsaturated monomer is preferably contained in the acrylic resin (A) in an amount of 1 to 30% by weight.
It is copolymerized, more preferably 2 to 20% by weight. If it is less than 1% by weight, sufficient low-temperature curability may not be obtained, and the adhesion, water resistance, chemical resistance, etc. may be deteriorated. If the copolymerization exceeds 30% by weight,
The storage stability at a high temperature of 50 ° C. or higher tends to deteriorate, and the coating film tends to generate blemishes.

In the present invention, in addition to the hydroxyl group-containing unsaturated monomer and the alicyclic epoxy group-containing unsaturated monomer, other copolymerizable unsaturated monomers can be copolymerized.

Examples of such other unsaturated monomers include methyl acrylate, ethyl acrylate, n-butyl acrylate, t-butyl acrylate, iso-butyl acrylate, propyl acrylate, cyclohexyl acrylate,
2-ethylhexyl acrylate, lauryl acrylate,
Such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, iso-butyl methacrylate, propyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate and the like ( For example, an alkyl ester of (meth) acrylic acid having 1 to 18 carbon atoms can be used. Further, copolymerizable unsaturated monomers such as styrene and vinyl acetate can also be used. Such unsaturated monomers may be used alone or as a mixture of two or more.

The acrylic resin (A) used in the present invention
As the acrylate resin (A), a benzotriazole-based UV absorber having a polymerizable unsaturated double bond, preferably obtained by copolymerizing 0.05 to 10% by weight, is also preferably used. .

The benzotriazole-based UV absorber having a polymerizable unsaturated double bond is not particularly limited as long as it has an unsaturated double bond. For example, 2- (2'-hydroxy) -5'-acryloxyethylphenyl) -2H-benzotriazole, 2- (2 '
-Hydroxy-5'-methacryloxyethylphenyl)
A (meth) acryloyl benzotriazole-based ultraviolet absorber such as -2H-benzotriazole can be used. The use of these polymerizable benzotriazole-based UV-absorbing compounds allows the curability of the coating,
It has an effect that storage stability is excellent and good weather resistance is maintained for a long period of time. Further, it is preferably used because it can also serve as protection for the undercoat paint and the substrate (prevention of fading and deterioration of the substrate due to light).

These benzotriazole-based ultraviolet absorbers having a polymerizable unsaturated double bond may be used alone or
It may be a mixture of two or more. It is desirable that these ultraviolet absorbers are simultaneously copolymerized when the acrylic resin (A) is produced, and incorporated into the acrylic resin as a component of the acrylic resin (A).

From the viewpoints of storage stability and good curability of the paint, a light-stable compound having a base constant (PKb) of 8 or more is preferably added to 100 parts by weight of the acrylic resin (A). By mixing 0.05 to 10 parts by weight, the weather resistance is further improved. Such photostable compounds include:
Copolymerizable piperidine-containing photostable compounds such as 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate can be used, and these monomers may be used alone or in combination of two or more. May be used.

Such a light-stable compound has the effect of dramatically improving the weather resistance of a coating film without impairing the storage stability and curability of the composition. The photostable compound is, in particular,
It is effective when enamel paints are blended with pigments such as titanium dioxide, carbon black and aluminum pigments, and extremely good weather resistance is obtained. That is, excellent performance can be obtained with respect to gloss retention and a change in the color tone of the coating film.

As the photostable compound having a base constant (PKb) of 8 or more, specifically, 1- {2- (3- (3,3)
5-di-t-butyl-4-hydroxyphenyl) propionyloxy) ethyl {-4-} 3- (3,5-di-t
-Butyl-4-hydroxyphenyl) propionyloxy {-2,2,6,6-tetramethylpiperidine, 8-
Acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro {4,5} decane-
2,4-dione and the like can be used.

Such light-stable compounds may be used alone or as a mixture of two or more. Such a photostable compound is based on 100 parts by weight of the acrylic resin (A).
Preferably 0.05 to 10 parts by weight, more preferably 0.5 to 5 parts by weight is blended. When the amount is less than 0.05 part by weight, the weather resistance improving function is not so good, and when the amount exceeds 10 parts by weight, the curability and storage stability of the paint may be slightly deteriorated.

Further, if necessary, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane,
Methacryloyloxypropyltriethoxysilane, 3
-Methacryloyloxypropylmethyldiethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, 3-acryloyloxypropyltriethoxysilane, 3-acryloyloxypropylmethyldiethoxysilane and the like. Hydrolysis of unsaturated monomers having a hydrolyzable alkoxysilane group, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldiethoxysilane, etc. It is also possible to copolymerize or blend a chain transfer agent (polymerization degree regulator) having a functional alkoxysilane group. Such monomers or chain transfer agents may be used alone or as a mixture of two or more.

The acrylic resin (A) of the present invention is produced as a solvent solution, an aqueous dispersion or the like by ordinary radical copolymerization. In the case of the present invention, α, α′-azobis is used by using an organic solvent such as toluene, xylene, butyl acetate, ethyl acetate, isopropyl alcohol, n-butyl alcohol, ethylene glycol monobutyl ether, propylene glycol monomethyl ether and cyclohexanone. Organic azo polymerization initiators such as isobutyronitrile and α, α′-azobisvaleronitrile, and organic peroxides such as benzoyl peroxide and t-butylperoxy-2-ethylhexanoate as polymerization initiators Used, preferably at a polymerization temperature of 40 to 150 ° C., solution polymerization of a hydroxyl group-containing unsaturated monomer, an alicyclic epoxy group-containing unsaturated monomer, and another copolymerizable unsaturated monomer. It is preferred to be manufactured.

The number average molecular weight (Mn) of the acrylic resin (A) of the present invention is preferably 2,000 to 8,000, more preferably 2,500 to 50,000. When the number average molecular weight is less than 2,000, the low-temperature curability tends to be slightly deteriorated, and the coating film tends to generate shrinkage. When the number average molecular weight exceeds 80000, the gloss of the coating film tends to decrease, and a good finished appearance may not be obtained. However, this is not the case when it is used for a base coat.

As is well known, the molecular weight of the acrylic resin (A) can be controlled by using a chain transfer agent such as n-dodecyl mercaptan at the time of producing the acrylic resin.

The number average molecular weight (Mn) of the acrylic resin (A) can be measured by using gel permeation chromatography (GPC; molecular weight measuring device manufactured by Tosoh Corporation).

The epoxy equivalent of the present invention is 100 to 1000.
The alicyclic epoxy resin (B) is 13599
Chemical Products (Chemical Kogyo Nippo, 1999) P
961-970, among which 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate and those having an alicyclic epoxy group in the molecule, such as those having the following formulas 1 to 5, are used. can do. Such compounds may be used alone or as a mixture of two or more.

[0032]

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[0033]

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[0034]

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[0035]

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[0036]

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When the epoxy equivalent of the alicyclic epoxy resin (B) is less than 100, the curability at low temperature is good, but the coating film is hard and brittle, and the low-temperature impact property and the flexibility are deteriorated. Sometimes. Also, if the epoxy equivalent is 100
If it exceeds 0, the curability is slightly delayed, the rise of the initial hardness of the coating film is delayed, and the initial scratch resistance, gasoline resistance, etc. may be slightly insufficient.

The alicyclic epoxy resin (B) preferably has a weight ratio of A / B = A to the acrylic resin (A).
50/50 to 99/1, more preferably 70/30 to
98/2, particularly preferably in the range of 85/15 to 98/2. If the amount of the alicyclic epoxy resin (B) is less than 1% by weight, the curability at low temperatures may deteriorate, and the water resistance, weather resistance, and the like tend to slightly deteriorate. If the amount is more than 50% by weight, the coating film tends to shrink and the gloss may be slightly lowered. In addition, when used as a base coat for a metallic paint, metal unevenness such as metal swimming may easily occur.

The organoalkoxysilane compounds (C) having a glycidyl group and a hydrolyzable alkoxysilane group in one molecule of the present invention include γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropyl. Triethoxysilane, γ-glycidoxypropyltriisopropoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyldimethoxysilane, β- (3,4-epoxycyclohexyl) Ethyltrimethoxysilane is exemplified. These compounds may be used alone or as a mixture of two or more. Hydrolysates and partial condensates of these compounds may also be used.

Such a compound is used alone or reacts with the alicyclic epoxy group and hydroxyl group of the side chain of the acrylic resin (A) and the alicyclic epoxy resin (B) to give a crosslinked structure to the coating film. can do. In order to obtain good low-temperature curability, it is essential that the silane compound has both a glycidyl group and a hydrolyzable alkoxysilane group (or silanol group). Tends to be difficult to obtain. For example, when a hydrolyzable alkoxysilane compound such as phenyltrimethoxysilane having no glycidyl group is used instead of the compound, a sufficient curing reaction does not occur at a low temperature of 80 ° C. or lower, and the water resistance is low. In addition, coating properties such as chemical resistance, gasoline resistance, and weather resistance tend to deteriorate.

Organoalkoxysilane compound (C)
Is preferably (A + B) / C = 6 in a weight ratio with respect to the total amount of the acrylic resin (A) and the alicyclic epoxy resin (B).
0/40 to 95/5, more preferably 60/40 to 9
Used in the range of 0/10. When the amount of the organoalkoxysilane compound (C) used is less than 5% by weight, the low-temperature curability is slightly deteriorated. In addition, the used amount is 6
If it exceeds 0% by weight, the recoat adhesion of the paint tends to be poor when repainting is performed to repair the defective portion of the coating film.

The resin composition of the present invention comprises an acrylic resin having a hydroxyl group and an alicyclic epoxy group in a side chain, an alicyclic epoxy resin, and a glycidyl group in one molecule as main reaction components for forming a crosslinked coating film. This is a composition having all of the organoalkoxysilane compounds having a hydrolyzable alkoxysilane group. In more detail, it is preferable that the main reaction component for forming a crosslinked coating film to be mixed has an epoxy group (glycidyl group). This results in excellent low-temperature curability (sufficient curing even at a curing temperature of 80 ° C or lower and various coating film performances are excellent), and storage stability (for paints in long-term storage (in a closed system)). Stability, exhibiting a sufficiently long pot life (in open system), touch-up properties (in the event of failure due to adhesion of dust on the painted film, sanding the film or repainting as it is To do,
Recoat adhesion). Furthermore, since the acrylic resin and the epoxy resin have an alicyclic epoxy group, they have been extremely resistant to acid rain and aluminum and iron, which have recently become extremely important concerns in the paint and coating industries. Demonstrate performance. Further, since a silane compound having a glycidyl group is compounded, an acrylic resin having an alicyclic epoxy group, an organic resin,
It exhibits excellent adhesion (adhesion) to various base materials regardless of inorganic properties, and exerts an effect of further enhancing the above-mentioned various properties.

In other words, the resin composition of the present invention greatly overturns the conventional concept of paint, enables many applications with a single paint, has high stability, and can be cured at low temperatures. Therefore, it can greatly contribute to resource saving and energy saving.

That is, these excellent performances include an acrylic resin having a hydroxyl group and an alicyclic epoxy group in a side chain, an alicyclic epoxy resin, and a glycidyl group in one molecule as a film-forming component. This is exhibited because the organoalkoxysilane compound having an alkoxysilane group is organically compounded.

Next, the aluminum chelate compound (D)
Examples thereof include aluminum ethyl acetoacetate diisopropylate, aluminum tris (ethyl acetoacetate), aluminum tris (acetyl acetate), and aluminum bisethyl acetoacetate monoacetylacetonate.

The aluminum chelate compound reacts with the acrylic resin, the alicyclic epoxy resin and the organoalkoxysilane compound to act as a catalyst and a crosslinking agent for forming a crosslinked coating film. Such compounds may be used alone or as a mixture of two or more.

The aluminum chelate compound (D) is preferably (A + B + C) / D = 100 / D in weight ratio with respect to the acrylic resin (A), the alicyclic epoxy resin (B) and the organoalkoxysilane compound (C). 0.5-100
/ 10, more preferably in the range of 100/1 to 100/5. When the use amount of the aluminum chelate compound (D) is less than 0.5% by weight, the curability at low temperatures may be deteriorated, and it may take time to obtain sufficient coating film performance. When used in an amount exceeding 10% by weight, storage stability and weather resistance may deteriorate.

It is well known that a corresponding chelating agent is added as a stabilizer so that it does not inadvertently perform its function during storage, and the present invention is suitably carried out. That is, in order to improve storage stability, it is preferable to add acetylacetone, diacetone alcohol, methyl acetoacetate, ethyl acetoacetate and the like.

Finally, the acrylic resin (E) having an alkoxysilane group in the molecule and having a number average molecular weight of 2,000 to 100,000 can be prepared by using 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyl Methyldimethoxysilane, 3
-Methacryloyloxypropyltriethoxysilane,
Hydrolysis of 3-methacryloyloxypropylmethyldiethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, 3-acryloyloxypropyltriethoxysilane, 3-acryloyloxypropylmethyldiethoxysilane, etc. It can be produced by copolymerizing an unsaturated monomer having a reactive alkoxysilane group and another unsaturated monomer.

Among these compounds, 3-methacryloxypropyltrimethoxysilane is particularly preferably used.
Thereby, a coating composition having excellent low-temperature curability at 80 ° C. or lower can be obtained.

Other unsaturated monomers include methyl acrylate, ethyl acrylate, n-butyl acrylate,
T-butyl acrylate, iso-butyl acrylate, propyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, n-methacrylic acid
Butyl, t-butyl methacrylate, iso methacrylate
-Alkyl esters of (meth) acrylic acid having 1 to 18 carbon atoms, such as -butyl, propyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, and stearyl methacrylate can be used. Further, copolymerizable unsaturated monomers such as styrene and vinyl acetate can be used. Such unsaturated monomers may be used alone or as a mixture of two or more.

The acrylic resin (E) can be produced in the same manner as the acrylic resin (A). That is, it can be produced either as a solvent solution or as an aqueous dispersion. For example, using an organic solvent such as toluene, xylene, butyl acetate, ethyl acetate, isopropyl alcohol, n-butyl alcohol, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, or cyclohexanone, α, α′-
Polymerization of an organic azo polymerization initiator such as azobisisobutyronitrile and α, α'-azobisvaleronitrile, and an organic peroxide such as benzoyl peroxide and t-butylperoxy-2-ethylhexanoate. It is preferably used as an initiator, and is preferably produced by solution polymerization of an alkoxysilane group-containing unsaturated monomer and another copolymerizable unsaturated monomer at a polymerization temperature of preferably 40 to 150 ° C.

The acrylic resin (E) is effectively compounded to adjust the hardness, elongation and the like of the paint.
Further, it has a remarkable effect on improving the appearance of the coating film. That is, by blending the compound, shrinkage of the coating film is improved, and a coating film with high gloss and sharpness can be formed.

The number average molecular weight of the acrylic resin (E) measured by GPC is preferably from 2,000 to 10,000.
0, more preferably 5,000 to 50,000. If the number average molecular weight is less than 2,000, the coating film becomes brittle, and the effect of improving the shrinkage may not be good. When the number average molecular weight is more than 100,000, the viscosity of the coating material is increased, and the workability may be deteriorated, or the storage stability of the coating material may be deteriorated.

Therefore, by simultaneously mixing the organoalkoxysilane compound (C) having a glycidyl group and a hydrolyzable alkoxysilane group in one molecule with the acrylic resin (E), the curability and physical properties of the paint can be improved. It is possible to significantly improve the appearance of the coating.

The acrylic resin (E) preferably has a weight ratio of C / E = 50/50 to 99.9 / 0.1, more preferably 60/40 to 100, based on the weight of the organoalkoxysilane compound (C). Used in the range of 98/2. When the amount used is less than 0.1, when the coating is carried out at the time of drying at a low temperature, shrinkage may occur, and the appearance of the coating film may be slightly deteriorated. If it is used in an amount exceeding 50% by weight, the storage stability and curability of the paint may be slightly deteriorated, and the coating properties such as water resistance and weather resistance may be reduced.

The resin composition of the present invention comprises an acrylic resin (A), an alicyclic epoxy resin (B) having an epoxy equivalent of 100 to 1,000, an organoalkoxysilane compound (C), an aluminum chelate compound (D), As long as the resin (E) is uniformly mixed, the production method is not particularly limited, but an example will be described.

An acrylic resin (A) and an alicyclic epoxy resin (B) having a specific structural formula are charged and stirred in a container equipped with a stirring device. Next, the aluminum chelate compound (D) is charged little by little and dissolved. Finally,
It can be produced by adding the organoalkoxysilane compound (C) and the acrylic resin (E) and continuing stirring until the mixture becomes uniform. During this manufacturing process, heating can be performed if necessary. However, it can be sufficiently manufactured even at room temperature, and the stability of the manufacturing (because the curing reaction proceeds during the manufacturing and no gel material is generated). From a viewpoint, it is preferable to manufacture in a temperature range of 20 to 50 ° C.

In order to more stably produce the paint, the acrylic resin (A) and the alicyclic epoxy resin (B) are charged, uniformly stirred and mixed, and then the organoalkoxysilane compound (C) and the acrylic resin are mixed. Charge (E) and mix until uniform. After the composition is made into a paint (production of a paint), an aluminum chelate compound (D) may be added last. At this time, the aluminum chelate compound (D) is an organic solvent such as toluene and xylene;
Further, if dissolved with a chelate stabilizer such as acetylacetone, the production is more simple and the production is stable.

As another method, particularly in the production of an enamel paint (colored paint in which a pigment is blended and dispersed), a mixed liquid of an acrylic resin (A) and an alicyclic epoxy resin (B) is produced. After that, pigment dispersion is performed with this composition.
A resin comprising an acrylic resin (A), an alicyclic epoxy resin (B), an organoalkoxysilane compound (C), and an acrylic resin (E) is prepared by using the enamel paint (mill base (pigment paste)) thus manufactured in advance. Let down (dilute to a proper paint viscosity and pigment blending amount) with a composition or a mixed solution of an organoalkoxysilane compound (C) and an acrylic resin (E), and finally, an aluminum chelate compound ( Alternatively, the above-mentioned diluent is added and mixed until the mixture becomes homogeneous. In short, the respective compositions may be simultaneously compounded or divided for use depending on usability or use, and finally may be combined into one.

The resin composition of the present invention, as a composition,
Alternatively, a paint is produced, that is, if necessary, a pigment such as titanium dioxide, carbon black, or aluminum paste, or a well-known paint additive [leveling agent, pigment dispersant, anti-settling agent, the present invention; A normal additive UV absorber other than a polymerizable benzotriazole UV absorber having an unsaturated double bond, and a base constant (PKb) of 8
The following light stabilizers, antifoaming agents, etc.], solvents for dilution (aliphatic and aromatic hydrocarbons, alcohols, ketones, ethers, esters, etc., dissolve or disperse resins, pigments, additives, etc. These compounds are used as a base coat (undercoat) or as a topcoat (overcoat), depending on the application. These may be used alone or in combination of two or more. Can be.
In addition, chlorinated polyolefins such as chlorinated polypropylene and chlorinated rubber and other paints, such as acrylic urethane resin paint, urethane resin paint, alkyd resin paint, epoxy resin paint, fluororesin paint, silicone resin paint,
Acrylic silicone resin paint, etc. (Reference: 13599
Can also be used in combination with the Chemical Products of Japan, Chemical Daily (published in 1999). That is, to give an example, it is also possible to apply a paint prepared using the composition of the present application as a base coat and then use an acrylic urethane resin paint as a top coat.

The base material on which the coating composition of the present invention can be applied includes plastics such as ABS (acrylonitrile-styrene-butadiene resin), polystyrene, polycarbonate, nylon, and the like; metals such as iron, aluminum, tin, and tin; These include those subjected to chemical conversion treatment, those subjected to cationic or anionic electrodeposition coating, and building materials such as mortar, cement, asbestos cement, asbestos cement perlite, bricks, tiles, and slate.

The coating method used is a coating prepared using the composition of the present application, such as spray coating, brush coating, roller coating, coating with a roll coater, curtain coating, anionic electrodeposition coating, and cationic electrodeposition coating. It is possible to employ methods commonly used in certain industries.

The coated articles can be used in a wide variety of applications. That is, for example, plastic parts and metal materials of automobiles and motorcycles (from small to large), plastic parts and metal members of household electric appliances, outer wall materials (sizing boards, curtain walls, aluminum sashes) ), Roof tiles, cosmetic accessories (containers, brushes, etc.) made of glass or plastic.

[0065]

The present invention will be described below in more detail with reference to examples. Unless otherwise specified, the number of parts indicates parts by weight and the composition ratio indicates% by weight. 1. Production of Resin Composition for Coating In the following examples, the following acrylic resin (A), epoxy resin (B), organoalkoxysilane (C), aluminum chelate (D), acrylic resin having an alkoxysilane group in the molecule ( E) was used. [Acrylic resin (A)] (1) Acrylic resin (1) α, α'-azobisisobutyronitrile (ABN) was used as a polymerization initiator, and toluene (TO) was used at a polymerization temperature of 93 ° C.
L) / Propylene glycol methyl ether (PM)
(= 60/40) as a solvent, methyl methacrylate (MMA) / n-butyl methacrylate (BMA) / n-butyl acrylate (BA) / 3,4-epoxycyclohexylmethyl acrylate (EPCA) / methacrylic acid 2 -Hydroxyethyl (HEMA, Tg = 40 ° C.)
(= 28/24/23/15/10) was subjected to solution polymerization to form an acrylic resin (1) (= solid content 60
%, Mn 18000, hydroxyl value 43 mg KOH, epoxy equivalent 1306). (2) Acrylic resin (2) Using ABN as a polymerization initiator, TO
Using L / PM (= 60/40) as solvent, MMA / BM
A / BA / EPCA / 4-hydroxybutyl acrylate (4HB, Tg = −80 ° C.) (= 28/24/23/1)
5/10) was subjected to solution polymerization to obtain an acrylic resin (2) (= 60% solids, Mn 18000, hydroxyl value 39 mg KOH, epoxy equivalent 1306). (3) Acrylic resin (3) Using ABN as a polymerization initiator, TO
Using L / PM (= 60/40) as solvent, MMA / BM
A / BA / EPCA / 4HB (= 28/24/23/1
5/10) is subjected to solution polymerization, and an acrylic resin (= solid content 60%, Mn 12,000, hydroxyl value 3)
9 mg KOH, epoxy equivalent 1306) were obtained. In addition, 8-acetyl-3-dodecyl-7,7,9,9
-Tetramethyl-1,3,8-triazaspiro @ 4
5-decane-2,4-dione (a photostable compound having a PKb of 8 or more (PKb 12), “Sanol LS-44
0 "(manufactured by Sankyo Co., Ltd.) so as to have a solid content of 2% to obtain an acrylic resin (3). (4) Acrylic resin (4) Using ABN as a polymerization initiator, TO
Using L / PM (= 60/40) as solvent, MMA / BM
A / BA / EPCA / 4HB (= 28/26/26/1
0/10) was subjected to solution polymerization to obtain an acrylic resin (4) (= 60% solids, Mn 35,000, hydroxyl value 39 mg KOH, epoxy equivalent 1960). (5) Acrylic resin (5) Using ABN as a polymerization initiator, TO
Using L / PM (= 60/40) as solvent, MMA / BM
A / BA / EPCA / 4HB / 2- (2'-hydroxy-5'-methacryloxyethylphenyl) -2H-benzotriazole (ultraviolet absorbent having a polymerizable unsaturated double bond, "RUVA-93" Otsuka Chemical Co., Ltd.) (=
28/26/24/10/10/10/2) by solution polymerization of an acrylic resin (5) (= solid content 60
%, Mn 15000, hydroxyl value 39 mg KOH, epoxy equivalent 1960). (6) Acrylic resin (6) Using ABN as a polymerization initiator, TO
Using L / PM (= 60/40) as solvent, MMA / BM
A / BA / glycidyl methacrylate / HEMA (= 2
8/21/21/10/20) by solution polymerization of an acrylic resin (6) (= 60% solid content, M
n15000, a hydroxyl value of 86 mgKOH, and an epoxy equivalent of 1420). (7) Acrylic resin (7) Using ABN as a polymerization initiator, TO
Using L / PM (= 60/40) as solvent, MMA / BM
Solution polymerization of a monomer mixture consisting of A / BA / HEMA (= 28/26/26/20), and acrylic resin (7)
(= 60% solid content, Mn30000, hydroxyl value 86 mg
KOH) was obtained. [Epoxy resin (B)] (1) 3,4-epoxycyclohexylmethyl-3,4
-Epoxy cyclohexyl carboxylate (ER
L), epoxy equivalent 131-143 Product name: “ERL-4221” manufactured by Union Carbide Japan Co., Ltd. (2) Bisphenol A type epoxy resin (EP) (epoxy equivalent 180-200) Product name: “EP-4100” Asahi [Organoalkoxysilane (C)] manufactured by Denka Kogyo Co., Ltd. (1) γ-glycidoxypropyltrimethoxysilane (GMP) Product name: “S-510” manufactured by Chisso Corporation (2) Hydrolyzate of silane compound ( Production Example of GMP-H) 28 g of ion-exchanged water (conductivity: 0.5 μs / cm) was placed in a 1 L four-necked flask equipped with a stirrer and a condenser.
390 g of γ-glycidoxypropyltrimethoxysilane
And stirred. While controlling the temperature to 10 ° C,
28 g of 0.1 mol / L hydrochloric acid was added dropwise over 3 hours. Thereafter, the reaction was carried out for 2 hours while stirring at 10 ° C.
Was continued to produce a hydrolyzate of the silane compound. [Aluminum chelate (D)] (1) Aluminum monoacetylacetonate bis (alkyl acetoacetate) Trade name: "Aluminum chelate DOL" (DOL) manufactured by Kawaken Fine Chemical Co., Ltd. [Acrylic resin having alkoxysilane group in molecule ( E)] (1) Acrylic resin (Si) having an alkoxysilane group
Production Example of -Ac) ABN was used as a polymerization initiator at a polymerization temperature of 93 ° C.
MMA / BMA / 3-methacryloxypropyltrimethoxysilane (= 15/80/5) using TOL as a solvent
A solution of a monomer mixture consisting of an acrylic resin (Si-Ac) having an alkoxysilane group (= 50% solids)
%, Mn 9000).

According to the blending weight ratios shown in Table 1, each raw material was charged into a stainless steel beaker and stirred at room temperature until it became uniform to produce each of the coating resin compositions of Examples 1 to 5 and Comparative Examples 1 to 4. .

[0067]

[Table 1]

2. Evaluation method 2.1. Preparation of Test Coated Plate Each coating resin composition is diluted with toluene / methylpropylene glycol / isopropyl alcohol (= 50/30/20) so that the coating viscosity becomes 15 seconds with a Ford cup # 4 (paint A).

The paint A was applied to an ABS plate degreased with isopropyl alcohol so that the coating thickness became 100 μm.
After drying in an atmosphere of 8 ° C. and 25% RH for 10 minutes,
Baking and drying were performed at 20 ° C. for 20 minutes. (Test coated plate 1) 2.2. Evaluation method of coated plate (1) The gloss of 20 ° and 60 ° gloss of test coated plate 1 was measured using a gloss meter VG.
1D [manufactured by Nippon Denshoku Industries Co., Ltd.].

The higher the value of both 20 ° gloss and 60 ° gloss, the better the gloss and uniformity of the coating film (smooth coating film with no smear). Both 20 ° gloss and 60 ° gloss,
A case of 90% or more is regarded as a pass. (2) The sharpness of the test coated plate 1 was measured using a portable clarity gloss meter PG.
D-IV (No. 88568) [Japan Color Research Institute,
Tokyo Electric Co., Ltd.]. The higher the value, the better the sharpness and uniformity of the coating film. A score of 0.8 or more is considered acceptable. (3) The overall smear of the coating film was determined from the measurement results in the above (1) and (2), and the smear at the edge was visually determined.

○: There is no blemishes at the edge portion, both 20 ° gloss and 60 ° gloss are 90% or more, and clearness is 0.5 or more. Pass.

Δ: There is a spot on the edge, but both the 20 ° gloss and the 60 ° gloss are 90% or more and the sharpness is 0.5 or more. Pass.

X: If the above condition is not satisfied, the test is rejected. (4) The coating film of the coated plate 1 was rubbed 50 times with a felt containing toluene (rubbing test with toluene), and the curability was determined based on whether the coating film was damaged.

：: The coating film was not damaged at all, and passed. Δ: The coating film was slightly damaged, but remained as a whole, and passed. ×: The coating film was dissolved and failed.

Table 2 shows the evaluation results. The evaluation criteria are as described above.

[0076]

[Table 2]

From the test results shown in Table 2, the coating films formed using the coating materials obtained in Examples 1 to 5 exhibited excellent curability even at low-temperature baking, and were beautiful without blemishes, as compared with Comparative Examples. It can be seen that the coating has the appearance and sharpness.

[0078]

According to the present invention, storage stability is good,
It is possible to provide a paint excellent in curability at a low temperature (80 ° C. or less) and excellent in weather resistance of the paint, particularly a one-pack type paint, which is suitable for coating on a substrate having relatively low heat resistance such as plastic. , Required performance (adhesion, appearance,
It is possible to provide a coating film that is well balanced in weather resistance, chemical resistance, solvent resistance, etc.).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 183/06 C09D 183/06

Claims (3)

[Claims] 1. An acrylic resin (A) having a hydroxyl group and an alicyclic epoxy group in a side chain, and an epoxy equivalent of 100 to 10
An alicyclic epoxy resin (B), an organoalkoxysilane compound (C) having a glycidyl group and a hydrolyzable alkoxysilane group in one molecule, an aluminum chelate compound (D), and an alkoxy group in the molecule. Having a silane group, having a number average molecular weight of 2,000 to 10,000
An acrylic resin (E) which is 0. A resin composition for a paint, comprising: 2. The coating resin composition according to claim 1, wherein (A) to (E) satisfy the following relational expression by weight ratio. (1) A / B = 50/50 to 99/1 (2) (A + B) / C = 60/40 to 95/5 (3) (A + B + C) /D=100/0.5 to 100 /
10 (4) C / E = 50 / 50-99.9 / 0.1 3. The coating resin composition according to claim 1, wherein the alkoxysilane group of the acrylic resin (E) is 3-methacryloxypropyltrimethoxysilane.