JPH0812934A - Topcoat forming method - Google Patents

Abstract

PURPOSE:To form a coating having excellent low-temp. curability, finish appearance, acid resistance, scratch resistance, weather resistance and other properties. CONSTITUTION:A topcoat forming method comprising forming a color base coat and a clear topcoat in that order on a base material, wherein the color base coat and/or the clear topcoat is formed by using a curable coating compsn. comprising (A) a resin (A-1) having an epoxy group (i), a reactive silicon group (ii), and a hydroxyl group and/or a carboxyl group (iii) as indispensable functional group components in its molecule or a mixed resin (A-2) composed of two or more resins each contg. at least one of the functional group components (i) to (iii), the mixed resin contg. all the functional group components (i) to (iii), (B) an organotin catalyst, and (C) a curable coating compsn. contg. an org. solvent as indispensable components.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel method for forming a top coating film, more specifically, finish and coating performance (acid resistance,
The present invention relates to a method for forming an overcoat coating film capable of forming a coating film having excellent scratch resistance and the like.

[0002]

2. Description of the Related Art In recent years, air pollution has progressed, and damage from acid rain such as forest death has become a serious social problem. However, coatings applied to articles used outdoors such as automobile exterior panels. Also in the film, there is a problem that the coating film is etched, and the coating film has whitening, stains, and the like. Therefore,
There is a strong demand for a coating film with good acid resistance.

Further, an overcoat film, for example, an overcoat film applied to an automobile outer panel or the like is apt to be scratched due to collision with sand or dust during traveling, rubbing by a cleaning brush or the like, and deterioration of appearance. It has become one of the causes, especially black,
Scratches are very noticeable on a dark-colored coating such as navy blue or brown. Therefore, there is a strong demand for improving the scratch resistance of the top coating film.

At present, a method for forming a topcoat coating film is widely used in which an amino-curable coating composition containing a hydroxyl group-containing resin and a binder amino resin is used as a coating composition for forming a topcoat coating film. An overcoat film satisfying both the scratch resistance has not been obtained.

As a method of using a composition other than the above amino-curable coating composition, a coating composition prepared by mixing a resin having an epoxy group and a hydroxyl group with a cyclic acid anhydride such as methylhexahydrophthalic anhydride as a curing agent. Is used as a coating composition for forming an overcoat coating film, a method for forming an overcoat coating film is disclosed in JP-A-63-84673 and JP-A-63-8.
It is described in Japanese Patent No. 4674. However, these methods have the drawback that the finished appearance, acid resistance, scratch resistance, etc. of the coating film are poor.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems. As a result, in the method for forming an overcoat coating film by sequentially forming a colored base coat and a clear top coat on the material, as the curable coating composition for forming the overcoat coating film, an epoxy group, a reactive silicon group, and a hydroxyl group and / or The composition containing a carboxyl group as an essential functional group component, using a curable coating composition containing an organic tin catalyst, it was found that a coating film can be formed in which the above-mentioned drawbacks of the prior art are eliminated.
The present invention has been completed.

That is, the present invention provides a method for forming a topcoat coating film in which a colored base coat and a clear top coat are sequentially formed on a material, wherein the colored base coat and / or the clear top coat is (A) (i) an epoxy group, (ii)
A resin (A-1) containing a reactive silicon group and (iii) a hydroxyl group and / or a carboxyl group in the same molecule as an essential functional group component, or the functional group component of (i) to (iii) above. A mixture of two or more kinds of resins each containing at least one kind of resin, wherein the mixture contains (i) to (ii) above.
i) a mixed resin (A-2) in which all the functional group components are present,
(B) Organotin catalyst, and (C) Organic solvent as a curable coating composition containing an essential component.

In the curable coating composition used in the present invention, the reactive silicon group means a silanol group which is a group in which a hydroxyl group is directly bonded to a silicon atom, or a group (hydrolyzable group in which a hydrolyzable group is directly bonded to a silicon atom). Group that produces a silanol group upon decomposition). Resin containing a reactive silicon group (A-
In 1) or the mixed resin (A-2), one or more of these groups may be present.

In the curable coating composition used in the present invention, the hydrolyzable group directly bonded to a silicon atom is, for example, an alkoxyl group represented by the general formula —OR ³ or a general formula —OCOR ^4. Acyloxy group and general formula-
A ketoxime group represented by ON = C (R ⁵ ) ₂ and the like are included. In the above general formulas, R ³ represents an alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, such as methyl, ethyl, propyl and butyl, and R ⁴ represents an alkyl group having 1 to 3 carbon atoms. , R ⁵ represents an alkyl group having 1 to ⁵ carbon atoms.

Preferred specific examples of the above hydrolyzable group include alkoxyl groups such as methoxy group, ethoxy group and propoxy group; ketoxime groups such as acyloxy group such as acetoxy group and propionyloxy group, acetoxime group and propionyloxime group. Groups and the like. Among these hydrolyzable groups, an alkoxyl group having 1 to 3 carbon atoms, which has excellent effects on storage stability and low temperature curability, is particularly preferable.

In the curable coating composition used in the present invention, the epoxy group in the component (A) is an aliphatic type epoxy group in which an ether group is bonded between the carbon atoms of a linear hydrocarbon group, or an alicyclic carbon group. Any type of alicyclic epoxy group having an ether group bonded between carbon atoms of a hydrogen group may be used, but in the case of an alicyclic epoxy group, the reactive silicon group in the component (A) and Since the cationic polymerization reaction or the cationic addition reaction easily and quickly occurs with the organotin catalyst as the component (B), it is characterized by excellent low-temperature curability.

In the method for forming a top coating film of the present invention, the material for forming the colored base coat is, for example,
Various metals, especially steel plates (chemical conversion treatment, chemical conversion treatment and primer electrodeposition coating, chemical conversion treatment, primer electrodeposition coating and intermediate coating coating, etc.), various plastics (surface treatment if necessary) Those which have been subjected to surface treatment and primer coating, those which have been subjected to surface treatment, primer coating and intermediate coating), and combinations thereof.

In the method of forming a top coating film of the present invention, one or both of the colored base coat and the clear top coat formed on the material are (A) (i) epoxy group, (ii) reactive silicon group, And (iii) a resin (A-1) containing a hydroxyl group and / or a carboxyl group in the same molecule as an essential functional group component, or at least one of the functional group components (i) to (iii) described above. 2 contained in resin
A mixture of more than one resin, the mixture comprising
Mixed resin (A) in which all functional group components (i) to (iii) are present
-2), (B) organotin catalyst, and (C) organic solvent as essential components.

The curable coating composition used in the method for forming a top coating film of the present invention will be described below.

In the curable coating composition used in the present invention, the hydroxyl group has the effect of improving the low temperature curability because the reaction with the epoxy group and the reactive silicon group is promoted in the presence of the organotin catalyst. .

Further, the carboxyl group is recognized to promote the reaction between the hydroxyl group and the reactive silicon group, and the reaction between the reactive silicon groups, whereby the effect of improving the low temperature curability can be obtained. And, the carboxyl group reacts with the epoxy group to form a cured film having excellent performance such as acid resistance, the carboxyl group is consumed by the reaction with the epoxy group, and the carboxyl group does not remain in the coating film, or Since only a small amount remains, it is effective in improving the water resistance, acid resistance, weather resistance and the like of the coating film.

Hereinafter, each component to be incorporated in the curable coating composition used in the present invention will be described in more detail.

(I) an epoxy group, (ii) a reactive silicon group, and
(iii) a hydroxyl group and / or a carboxyl group as an essential functional group
In the resin (A-1) resin (A-1) contained in the same molecule as a component, the number of epoxy groups in the molecule is preferably about 1 or more on average, preferably about 2 to 100 on average. If the number of epoxy groups is less than about 1 on average in one molecule, low-temperature curability is deteriorated, which is not preferable.

The number of reactive silicon groups is preferably about 1 or more on average in one molecule, preferably about 1 to 300 on average. If the number of reactive silicon groups is less than about 1 on average in one molecule, low-temperature curability is deteriorated, which is not preferable.

The number of hydroxyl groups and / or carboxyl groups is
When the hydroxyl group is alone, the hydroxyl value is about 10 to 300, preferably in the range of about 20 to 200. When the carboxyl group is alone, the acid value is about 10 to 300, preferably about 20 to 200.
When the hydroxyl group and the carboxyl group are combined, the hydroxyl value is about 1 to 300, preferably about 2 to 200, and the acid value is about 1 to 300, preferably about 2 to 200. It is suitable.

When the number of hydroxyl groups and / or carboxyl groups is less than the above range, the low temperature curability is deteriorated, while when it exceeds the above range, the storage stability of the composition, the durability of the cured film and the like are deteriorated. Absent.

The resin (A-1) has an average molecular weight of about 200-
The range is 100,000, preferably about 500 to 50,000. If the average molecular weight is less than about 200, the durability of the cured product will decrease, while if it exceeds about 100,000, the storage stability, the appearance of the cured product, etc. will deteriorate.

The resin (A-1) is conventionally known as long as it satisfies the above conditions, for example, a polymer of an ethylenically unsaturated monomer, a polyester resin,
A silicon-modified polyester resin, an epoxy-modified polyester resin, a silicon-modified epoxy resin, a fluororesin or the like can be appropriately selected and used, but a polymer of the following ethylenically unsaturated monomer is particularly preferable.

The polymers of ethylenically unsaturated monomers include the following epoxy group-containing ethylenically unsaturated monomers (a); reactive silicon group-containing ethylenically unsaturated monomers (b); hydroxyl group-containing ethylenically unsaturated monomers. Monomers (c)
And / or carboxyl group-containing ethylenically unsaturated monomers (d); and, if necessary, those obtained by radical copolymerization reaction with other ethylenically unsaturated monomers (e). Epoxy group-containing ethylenically unsaturated monomers (a): glycidyl (meth) acrylate, methylglycidyl (meth) acrylate, allyl glycidyl ether, 3,4-epoxycyclohexylmethyl (meth) acrylate, etc. Reactive silicon group-containing ethylenic Unsaturated monomers (b):
Vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, γ
-(Meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane, γ- (meth) acryloyloxypropylmethyldimethoxysilane, β- (meth) acryloyloxyethylpropyltrimethoxysilane, and these And a trifunctional silane compound, a tetrafunctional silane compound, and a low-condensation product of a tetrafunctional silane compound, which will be described later as an explanation of the reactive silicon-containing resin, and a hydroxyl group-containing ethylenically unsaturated monomer (c And a reaction product of the above low condensate, etc., hydroxyl group-containing ethylenically unsaturated monomers (c): hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, (poly) ethylene glycol mono (meth) acrylate, ( Poly) propylene glycol (Meth) acrylates, adducts of these with caprolactone (ε-caprolactone, etc.), the following hydroxyl group-containing ethylenically unsaturated monomers (c) and acid anhydrides (for example, succinic anhydride, hexahydrophthalic anhydride, anhydrous (Trimellitic acid) adduct, etc., (anhydrous) carboxyl group-containing ethylenically unsaturated monomer (d): (meth) acrylic acid, (anhydrous) maleic acid, etc. Other ethylenically unsaturated monomer (e): Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth)
C _1-24 alkyl (meth) acrylates or cycloalkyl (meth) acrylates such as acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate and cyclohexyl (meth) acrylate, perfluoro Butylethyl (meth) acrylate, hydroxyethyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, perfluoroisononylethyl (meth) acrylate, perfluorodecylethyl (meth)
Perfluoroalkyl group- or perfluoroalkenyl group-containing ethylenically unsaturated monomers such as acrylates, aromatic vinyl monomers such as styrene and vinyltoluene,
Nitrile monomers such as (meth) acrylonitrile,
Amide monomers such as (meth) acrylamide and N-methylol (meth) acrylamide.

(I) Epoxy group, (ii) Reactive silicon group,
And (iii) at least a hydroxyl group and / or a carboxyl group
A mixture of two or more resins, one of which is contained in each resin
Wherein the functional groups of (i) to (iii) above are contained in the mixture.
Mixed resin (A-2) in which all components are present As the above - mentioned mixed resin (A-2), for example, the following ones can be mentioned.

(I) A mixed resin of an epoxy group-containing resin and a reactive silicon group-containing resin, and at least one of the epoxy group-containing resin and the reactive silicon group-containing resin,
A mixture of two kinds of resins having a hydroxyl group and / or a carboxyl group.

(II) A mixture of three kinds of resins consisting of an epoxy group-containing resin, a reactive silicon group-containing resin, and a hydroxyl group and / or carboxyl group-containing resin.

(III) A mixture of an epoxy group-containing resin, a reactive silicon group-containing resin, and a hydroxyl group- and / or carboxyl group-containing resin, and at least one resin selected from the epoxy group-containing resin and the reactive silicon group-containing resin. , A mixture of three types of resins having a hydroxyl group and / or a carboxyl group.

(IV) A mixture of two kinds of resins comprising an epoxy group- and reactive silicon group-containing resin and a hydroxyl group- and / or carboxyl group-containing resin.

These mixed resins (I) to (IV) will be described in detail below.

(I) A mixed resin of an epoxy group-containing resin and a reactive silicon group-containing resin, and at least one of the epoxy group-containing resin and the reactive silicon group-containing resin,
Mixture of two types of resins having a hydroxyl group and / or a carboxyl group: Examples of the mixed resin (I) include the following.

(1) A mixed resin of an epoxy group- and hydroxyl group-containing resin and a reactive silicon group-containing resin.

(2) Epoxy group-containing resin and mixed resin of reactive silicon group- and hydroxyl group-containing resin.

(3) A mixed resin of an epoxy group- and hydroxyl group-containing resin and a reactive silicon group- and hydroxyl group-containing resin.

(4) Epoxy group-containing resin and mixed resin of reactive silicon group- and carboxyl group-containing resin.

(5) Epoxy group-containing resin and mixed resin of reactive silicon group, hydroxyl group and carboxyl group-containing resin.

(6) Mixed resin of epoxy group- and hydroxyl group-containing resin, and reactive silicon group- and carboxyl group-containing resin.

(7) Epoxy group- and hydroxyl group-containing resin, and mixed resin of reactive silicon group-, hydroxyl group- and carboxyl group-containing resin.

The epoxy group-containing resin described in (2), (4) and (5) above has an average number of epoxy groups of 1 or more, preferably about 2 to 100, in one molecule. Thus, those having an average molecular weight of about 130 to 100,000, preferably about 200 to 80,000 are suitable.

Examples of the epoxy group-containing resin include:
Polymers of the above-mentioned epoxy group-containing ethylenically unsaturated monomers (a) and, if necessary, the above-mentioned other ethylenically unsaturated monomers (e); bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4
-Epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate, 3,4-epoxycyclohexenecarboxylic acid ethylene glycol diester, 3, Alicyclic epoxy compounds such as 4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate; (poly) ethylene glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, epoxidized polybutadiene , Triglycidyl isocyanurate and other aliphatic epoxy compounds; bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol B type epoxy resin Hydrogenated bisphenol type epoxy resins, phenol novolak type epoxy resin of the resin and glycidyl ether type epoxy resin obtained by reacting a these things and epichlorohydrin.

Polymers of the above-mentioned epoxy group-containing ethylenically unsaturated monomers (a) and, if necessary, other ethylenically unsaturated monomers (e), particularly have an average molecular weight of about 5,000 to 100,000. Is preferred.

The epoxy group- and hydroxyl group-containing resins described in (1), (3), (6) and (7) above have an average number of epoxy groups of 1 or more, preferably about 1 in one molecule. 2 to 100, a hydroxyl value of about 10 to 300, preferably about 20 to 200, and an average molecular weight of about 1,000 to 100,000, preferably about 5,000.
Those in the range of to 80,000 are preferable.

As the epoxy group- and hydroxyl group-containing resin,
For example, an epoxy group-containing ethylenically unsaturated monomer (a), a hydroxyl group-containing ethylenically unsaturated monomer (c),
Further, if desired, a radical copolymer of other ethylenically unsaturated monomers (e) can be mentioned as a preferable one.

The reactive silicon group-containing resin described in (1) above has an average number of reactive silicon groups of 1 or more, preferably 1 to 300, in one molecule. Average molecular weight about 76-100,000, preferably about 100
Those in the range of up to 50,000 are preferred.

As the above-mentioned reactive silicon group-containing resin,
For example, methoxytrimethylsilane, ethoxytriethylsilane, propoxytripropylsilane, butoxytributylsilane, methoxytrioctylsilane, methoxytriphenylsilane, methoxytribenzylsilane,
Monofunctional silane compounds such as triphenylhydroxysilane; dimethoxydimethylsilane, dimethoxydiethylsilane, diethoxydiphtylsilane, dipropoxydipropylsilane, dimethoxydilaurylsilane, dimethoxydiphenylsilane, dimethoxydibenzylsilane, methoxybenzyloxydipropyl Bifunctional silane compounds such as silane, methoxy 2-ethylhexyloxydipropylsilane, diphenylsilanediol; trimethoxymethylsilane, triethoxyethylsilane, tripropoxypropylsilane, trimethoxystearylsilane, trimethoxyphenylsilane, trimethoxybenzylsilane. , Methoxydibenzyloxypropylsilane, methyltrihydroxysilane, phenyltrihydroxysilane, etc. A tetrafunctional silane compound such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane; a low condensate of the tetrafunctional silane compound; a modified silicon condensate of a low condensate of the tetrafunctional silane compound; the reactive silicon group-containing ethylene Preferred examples thereof include a radical unsaturated polymer (b) and, if necessary, a radical polymer of the other ethylenically unsaturated monomers (e).

The low-condensation product of the above-mentioned tetrafunctional silane compound is represented by the formula: Si (OR ⁶ ) ₄ (wherein R ⁶ are the same or different and each represents a hydrogen atom, a methyl group, an ethyl group or a propyl group). .) About 2 to 100 mer obtained by condensation reaction of tetraalkoxysilanes represented by
It is preferably about 2 to 10 mer. Examples of the low-condensation product include "Colcoat ES40" (trade name, manufactured by Colcoat Co., Ltd., 1 to 10 mer of tetraethyl silicate, about 5 mer on average) "Colcoat MS5"
1 "(1 to 10 mer of tetramethyl silicate, average about 4 mer) and the like. These Colconate low condensates are generally of the formula

[0047]

Embedded image

(Wherein R ⁶ has the same meaning as described above,
q shows the integer of 1-10. ) Is considered to have a structure represented by.

The modified silicon condensate of a low condensate of a tetrafunctional silane compound is a monovalent hydrocarbon in which a part of R ⁶ bonded to a silicon atom is C _4-24 (preferably C _4-8 ). A modified silicon condensate substituted with a group (which may contain an ether bond and / or an ester bond) and the like are included.

The C _4-24 monovalent hydrocarbon group in the modified silicon condensate is, for example, a cyclic or linear branched chain such as butyl, pentyl, hexyl, heptyl, octyl, decyl, stearyl, cycloalkyl and the like. It includes an optionally substituted alkyl group, an aryl group such as phenyl, toluyl, xylyl and the like, an aralkyl group such as benzyl (an alkyl group substituted with an aryl group) and the like.

The hydrocarbon group containing an ether bond is, for example,

[0052]

Embedded image

(In the formula, m is 1, 2 or 3, p is 1 or 2, and R ⁷ is a C _1-8 alkyl group.),

[0054]

[Chemical 4]

(In the formula, m has the same meaning as described above.)
Etc. are included. In particular,

[0056]

Embedded image

And the like.

The hydrocarbon group containing an ester bond is, for example,

[0059]

[Chemical 6]

(In the formula, R ⁸ represents a C _1-8 cyclic or linear alkyl group which may be branched, an aryl group or an aralkyl group, and m represents the same meaning as described above. .)
Etc. are included. In particular,

[0061]

[Chemical 7]

And the like.

Further, the hydrocarbon group containing both ether bond and ester bond is, for example,

[0064]

Embedded image

(In the formula, s is an integer of 2 or more, preferably 2
It represents an integer of 10 and m and R ⁸ have the same meanings as described above. ) Etc. are included. In particular,

[0066]

[Chemical 9]

And the like.

The modified silicon condensate is obtained, for example, by subjecting a monomer in which part of R ^{6 in} the tetraalkoxysilane is replaced with a C _4-24 monovalent hydrocarbon group as a starting material, and subjecting this to a condensation reaction. Or a low-condensation product of the tetraalkoxysilane and a C _4-24 alcohol (which may contain an ether bond or an ester bond) are subjected to a dealcoholization reaction so that part of R ⁶ of the low-condensation product is converted into a C _4-24 compound. It can be produced by substituting with a hydrocarbon group.

The reactive silicon group- and hydroxyl group-containing resin described in (2) and (3) above has an average number of reactive silicon groups of about 1 or more, preferably about 1 to 300, in one molecule. Range, the hydroxyl value is about 10 to 300, preferably about 20.
200, with an average molecular weight of about 1,000 to 10
Those in the range of 50,000, preferably in the range of about 5,000 to 80,000 are suitable.

Examples of the resin containing a reactive silicon group and a hydroxyl group include, for example, a reactive silicon group-containing ethylenically unsaturated monomer (b), a hydroxyl group-containing ethylenically unsaturated monomer (c) and, if necessary, other ethylenic Radical copolymers of unsaturated monomers (e) and the like are preferred.

The reactive silicon group- and carboxyl group-containing resins described in (4) and (6) above have an average number of reactive silicon groups of about 1 or more, preferably about 1 to 1 in one molecule.
A range of 300, an acid value of about 10 to 300, preferably about 20 to 200, and an average molecular weight of about 1,000.
-100,000, preferably about 5,000-80,0
A range of 00 is preferable.

Examples of the reactive silicon group- and carboxyl group-containing resin include, for example, the reactive silicon group-containing ethylenically unsaturated monomer (b), the carboxyl group-containing ethylenically unsaturated monomer (d) and, if necessary, other Radical copolymers of ethylenically unsaturated monomers (e) and the like are preferred.

In the reactive silicon group-, hydroxyl group- and carboxyl group-containing resin described in the above (5) and (7), the number of reactive silicon groups is an average of about 1 or more, preferably an average of about 1 in one molecule. To 300, a hydroxyl value and an acid value of about 10 to 300, preferably about 20 to 200, and an average molecular weight of about 1,000 to 100,000, preferably about 5,000 to 80, Those in the range of 000 are preferable.

Examples of the resin containing a reactive silicon group, a hydroxyl group and a carboxyl group include, for example, a reactive silicon group-containing ethylenically unsaturated monomer (b), a hydroxyl group-containing ethylenically unsaturated monomer (c) and a carboxyl group-containing ethylenic unsaturated monomer. Preferred examples include a saturated monomer (d) and, if necessary, a radical copolymer of other ethylenically unsaturated monomers (e).

In the mixed resin (I) described above, the mixing ratio of the epoxy group-containing resin and the reactive silicon group-containing resin is
Based on the total weight of the epoxy group-containing resin and the reactive silicon group-containing resin, the epoxy group-containing resin is in the range of about 5 to 95% by weight, preferably about 20 to 80% by weight, and the reactive silicon group-containing resin is about 5%. ~ 95% by weight, preferably about 20-8
It is preferable to set it in the range of 0% by weight. If the mixing ratio is out of this range, low-temperature curability, acid resistance, scratch resistance and the like are deteriorated, which is not preferable.

(II) Mixture of three kinds of resins consisting of epoxy group-containing resin, reactive silicon group-containing resin, and hydroxyl group and / or carboxyl group-containing resin: Examples of the epoxy group-containing resin include the above-mentioned mixed resin ( The same epoxy group-containing resin as described in (2) in I) can be used.

As the reactive silicon group-containing resin, for example, the same resin as the reactive silicon group-containing resin described in (1) of the mixed resin (I) can be used.

The number of hydroxyl groups and / or carboxyl groups in the resin containing hydroxyl groups and / or carboxyl groups is about 10 to 30 when the hydroxyl group is contained alone.
0, preferably in the range of about 20 to 200, when the carboxyl group is contained alone, the acid value is about 10 to 300, preferably in the range of about 20 to 200, when both the hydroxyl group and the carboxyl group are contained, A hydroxyl value of about 1 to 300, preferably about 2 to 200, and an acid value of about 1 to 300, preferably about 2 to 200 are suitable.

The average molecular weight of the hydroxyl group- and / or carboxyl group-containing resin is preferably in the range of about 1,000 to 100,000, preferably 5,000 to 80,000.

As the hydroxyl group-containing resin, for example, conventionally known resins such as (co) polymers of ethylenically unsaturated monomers, polyester resins, alkyd resins and polyether resins can be used. Radical (co) polymers of unsaturated monomers (c), and optionally other ethylenically unsaturated monomers (e) are suitable.

As the carboxyl group-containing resin, for example, conventionally known resins such as (co) polymers of ethylenically unsaturated monomers, polyester resins and alkyd resins can be used. Particularly, carboxyl group-containing ethylenically unsaturated resins can be used. Radical (co) polymers of the monomer (d) and, if necessary, other ethylenically unsaturated monomers (e) are preferable.

As the hydroxyl group- and carboxyl group-containing resin, conventionally known resins such as copolymers of ethylenically unsaturated monomers, polyester resins and alkyd resins can be used. Particularly, hydroxyl group-containing ethylenically unsaturated monomers are usable. Radical (co) polymers of (c), the carboxyl group-containing ethylenically unsaturated monomer (d), and optionally other ethylenically unsaturated monomers (e) are preferable.

In the above mixed resin (II), the mixing ratio of the epoxy group-containing resin, the reactive silicon group-containing resin, and the hydroxyl group- and / or carboxyl group-containing resin is 3% or more.
Epoxy group-containing resin is about 5 to 95% by weight, preferably about 20 to 80% by weight, based on the total weight of the various types of resins.
Range of about 5 to 95% by weight of the reactive silicon group-containing resin, preferably about 20 to 80% by weight, and about 10 to 70% by weight of the hydroxyl group and / or carboxyl group-containing resin, preferably about 20 to 60% by weight. It is preferable to set it in the range of% by weight. If the mixing ratio is out of this range, low-temperature curability, acid resistance, scratch resistance and the like are deteriorated, which is not preferable.

(III) A mixture of an epoxy group-containing resin, a reactive silicon group-containing resin, and a hydroxyl group- and / or carboxyl group-containing resin, and at least one resin selected from the epoxy group-containing resin and the reactive silicon group-containing resin. , A mixture of three kinds of resins having a hydroxyl group and / or a carboxyl group: Examples of the epoxy group-containing resin and the reactive silicon group-containing resin include the epoxy group-containing resin and the reactive silicon group in the mixed resin (I) described above. The same as the contained resin can be used.

As the hydroxyl group- and / or carboxyl group-containing resin, for example, the same resins as the hydroxyl group- and / or carboxyl group-containing resin in the mixed resin (II) can be used.

As the mixed resin (III), for example, a resin containing an epoxy group, a hydroxyl group and a reactive silicon group, a resin containing a reactive silicon group, and a mixed resin containing a resin containing a hydroxyl group and a carboxyl group can be used.

Examples of the epoxy group-, hydroxyl group- and reactive silicon group-containing resin include epoxy group-containing ethylenically unsaturated monomer (a), hydroxyl group-containing ethylenically unsaturated monomer (c) and reactive silicon group-containing ethylenic resin. A radical copolymer of the unsaturated monomer (b) and optionally other ethylenically unsaturated monomers (e) is included.

In the above-mentioned mixed resin (III), the mixing ratio of the epoxy group-containing resin, the reactive silicon group-containing resin, and the hydroxyl group- and / or carboxyl group-containing resin is based on the total measurement of these three kinds of resins. The epoxy group-containing resin is in the range of about 5 to 95% by weight, preferably about 20 to 80% by weight, the reactive silicon group-containing resin is in the range of about 5 to 95% by weight,
It is preferable that the range is about 20 to 80% by weight, and the range is about 10 to 70% by weight, and preferably about 20 to 60% by weight, in the hydroxyl group- and / or carboxyl group-containing resin. If the mixing ratio is out of this range, low-temperature curability, acid resistance, scratch resistance and the like are deteriorated, which is not preferable.

(IV) Epoxy group- and reactive silicon group-containing resin, and a mixture of two kinds of resins containing a hydroxyl group and / or a carboxyl group-containing resin: The epoxy group and the reactive silicon group-containing resin include the number of epoxy groups. Is an average of about 1 or more in one molecule, preferably about 2 to 100 on average,
The number of reactive silicon groups is in the range of about 1 or more on average in one molecule, preferably about 1 to 300, and the average molecular weight is about 1,000 to 100,000, preferably about 5,000.
Those in the range of to 80,000 are preferable.

Examples of the epoxy group- and reactive silicon group-containing resin include, for example, epoxy group-containing ethylenically unsaturated monomer (a), reactive silicon group-containing ethylenically unsaturated monomer (b) and, if necessary, other Radical copolymers of ethylenically unsaturated monomers (e) can be used.

Examples of the hydroxyl group- and / or carboxyl group-containing resin include those similar to the hydroxyl group- and / or carboxyl group-containing resin in the mixed resin (II) described above.

In the above-mentioned mixed resin (IV), the mixing ratio of the epoxy group- and reactive silicon group-containing resin and the hydroxyl group- and / or carboxyl group-containing resin is based on the total measurement of the two. The group-containing resin is in the range of about 30 to 90% by weight, preferably about 40 to 80% by weight, and the hydroxyl group and / or carboxyl group-containing resin is about 1%.
A range of 0 to 70% by weight, preferably about 20 to 60% by weight is suitable. If the mixing ratio is out of this range, low-temperature curability, acid resistance, scratch resistance and the like are deteriorated, which is not preferable.

In the above mixed resin (A-2), if the number of epoxy groups and reactive silicon groups deviates from the above range, low temperature curability, acid resistance, scratch resistance and the like are deteriorated, which is not preferable. On the other hand, if the average molecular weight is less than the above range, the durability of the coating film decreases, while if it exceeds the above range, the storage stability, the appearance of the coating film, etc. are deteriorated.

In the present invention, the radical polymerization reaction carried out to obtain each of the above resin components can be carried out by a conventionally known method. For example, a radical polymerization initiator (eg, azoisobutyronitrile, azobisdimethyl) In the presence of valeronitrile, di-tert-butyl hydroperoxide, benzoyl peroxide, etc.) in an organic solvent (eg, ketone type, ester type, alcohol type, ether type, hydrocarbon type, etc.), for example, about 60 ~ 200 ° C
Then, the ethylenically unsaturated monomer may be polymerized for about 1 to 10 hours.

Organotin Catalyst (B) Organotin catalyst (B) usable in the present invention includes:
A compound in which an organic group is bonded to a divalent or tetravalent tin atom, which is a liquid or solid organotin catalyst (B-1) having a boiling point of 150 ° C. or higher at room temperature (20 ° C.), and a tin atom The organotin chelate catalyst (B-2) in which an organic chelating agent is chelated to part or all of the tetravalent valence is included, and one kind or two or more kinds of them can be used.

Organotin catalyst (B-1): Organotin catalyst (B-
In 1), examples of the organic group bonded to the tin atom include a monovalent hydrocarbon group having 1 to 20 carbon atoms, a group containing an ether bond and / or an ester bond together with this hydrocarbon group, and the like. Furthermore, the organotin catalyst (B-1) contains 1
Those having two or more tin molecules in the molecule are also included.

In the present invention, the above-mentioned organotin catalyst (B
Among the -1), a curable composition using an organotin compound represented by the following general formula (I) or (II) containing a hydrocarbon group and an ether bond and / or an ester bond as an organic group is stable in storage. Of the general formula (I) are particularly preferable because of the advantages of improved properties such as heat resistance, low temperature curability and yellowing resistance.

(R ¹ ) _n Sn (OR ² ) _4-n (I) (R ¹ ) _u Sn (OR ² ) _2-u (II) (In the formula, R ¹ is the same or different and It represents a monovalent hydrocarbon group of 1 to 20. R ^{2 s} are the same or different,
A monovalent hydrocarbon group having 1 to 20 carbon atoms, -COCH = CH
COOR ¹ group or

[0099]

[Chemical 10]

Is shown. In addition, n represents an integer of 0 or 1 to 3, and u represents an integer of 0 or 1. ) The organotin catalysts may be used alone or in combination of two or more.

The above-mentioned organic group and the general formula (I) or (I
1 to 2 carbon atoms of the organotin catalyst (B-1) represented by I)
The monovalent hydrocarbon group of 0 may be any type of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group and a combination of these groups. The aliphatic hydrocarbon group may be linear or branched, and may contain an unsaturated bond, for example, methyl, ethyl, n-propyl, iso-propyl, n-butyl, i.
so-butyl, tert-butyl, n-pentyl, is
o-pentyl, tert-pentyl, neo-pentyl, n-hexyl, n-heptyl, n-octyl, n-
Examples thereof include nonyl, n-decyl, dodecyl, tridecyl and tetradecyl groups.

Examples of the alicyclic hydrocarbon group include a cyclohexyl group and the like. Examples of the aromatic hydrocarbon group include phenyl, methylphenyl, dimethylphenyl, toluyl and xylyl groups. In addition, examples of the group in which the aliphatic hydrocarbon group and the aromatic hydrocarbon group are combined include a benzyl group and a phenethyl group.
Among these hydrocarbon groups, an alkyl group having 1 to 20 carbon atoms and a phenyl group are preferable.

In the organotin catalyst (B-1) of the above general formula (I) or (II), R ² is

[0104]

[Chemical 11]

Those having an ester bond are excellent in storage stability and low temperature curability. Further, in the general formula (I) or (II), it is preferable that R ¹ is an alkyl group having 1 to 20 carbon atoms or a phenyl group.

Furthermore, the organotin catalyst (B) represented by the above general formula (I) is used.
In -1), particularly, those in which n is 0 or 1 are excellent in storage stability, low temperature curability and the like.

Organotin catalyst (B-1) of the above general formula (I)
As those having an ester bond, for example, tin tetraacetate, tin tetraoctate, tin tetralaurate, butyltin triacetate, butyltin tributyrate, butyltin trihexylate, butyltin trioctate, butyltin trilaurate, butyltin. Trimethylmalate, octyltin triacetate, octyltin tributyrate, octyltin trihexylate, octyltin trioctate, octyltin trilaurate, octyltin trimethylmalate,
Phenyltin tributyrate, phenyltin trilaurate, dibutyltin diacetate, dibutyltin dibutyrate, dibutyltin dihexylate, dibutyltin dioctate, dibutyltin dilaurate, dibutyltin diethylmalate, dioctyltin diacetate, dioctyltin dibutyrate, dioctyltin Dihexylate, dioctyltin dioctate, dioctyltin dilaurate, dioctyltin diethylmalate, tributyltin acetate, tributyltin butyrate, tributyltin hexylate, tributyltin octate, tributyltin laurate, tributyltin methylmalate, trioctyltin acetate, Trioctyl tin butyrate, trioctyl tin hexylate, trioctyl tin octate Trioctyltin laurate, it includes trioctyltin methyl maleate and the like. In addition, examples containing an ether bond include butyltin trimethoxy, butyltin tributoxy, octyltin trimethoxy, phenyltin trimethoxy, dibutyltin dimethoxy, dioctyltin dimethoxy, dioctyltin dibutoxy, tributyltin butoxy, and the like.

Among the above, tin tetraacetate, butyltin triacetate, butyltin tributyrate, butyltin trioctate, butyltin trilaurate, octyltin triacetate, octyltin tributyrate and the like are particularly preferable.

Organotin catalyst (B-1) of the above general formula (II)
Examples thereof include tin diacetate, tin dibutyrate, tin dioctate, and tin dilaurate.

Organotin chelate catalyst (B-2): The organotin chelate catalyst (B-2) is a compound in which an organic chelating agent is chelated to part or all of the tetravalent valence of tin atom.

As the organic chelating agent, a conventionally known organic chelating agent can be used, and the organic chelating agent includes a compound containing at least one atom selected from oxygen atom, sulfur atom and nitrogen atom. To be done. Among the above, a compound containing an oxygen atom, and further a compound capable of forming a keto / enol tautomer are preferable.

Examples of the compound capable of forming the keto-enol tautomer include β-diketones (acetylacetone and the like), acetoacetic acid esters (methyl acetoacetate and the like),
Malonic acid esters (ethyl malonate, etc.), ketones having a hydroxyl group at the β-position (diacetone alcohol, etc.), aldehydes having a hydroxyl group at the β-position (salicylaldehyde, etc.), esters having a hydroxyl group at the β-position ( Methyl salicylate, etc.) and the like can be used. Particularly, preferable results are obtained by using acetoacetic acid esters and β-diketones.

The organotin chelate catalyst (B-2) is prepared by mixing an organic chelating agent in a molar ratio of usually about 1 to 10 mol with respect to 1 mol of a tetravalent tin compound, and heating the mixture as necessary. It can be prepared by

Examples of the tin compound include organic acid salts, alkoxides, hydroxides, halides, sulfides, and combinations of these compounds. The organic acid salt and alkoxide in the tin compound include the organic tin compound represented by the general formula (I).

Examples of the halide in the above tin compound include a stannic chloride compound. As the sulfide, for example, the general formula _{^{(III) (R 1) n}} Sn (SR 9) 4-n (III) ( In the formulas, R ⁹ are the same or different, from 1 to 20 carbon atoms
A monovalent hydrocarbon group or -C _v H _2v COOR ¹ groups. v represents an integer of 1 to 4. R ¹ and n have the same meanings as described above. ) Are included. The monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ⁹ includes the same ones as described above.

Specific examples of the sulfide include C _{4
H 9 Sn (SCH 2 COOC 8} H 17) 3, (C 4 H 9)
₂ Sn (SCH ₂ COOC ₈ H ₁₇ ) ₂ , C ₈ H ₁₇ Sn
(SCH ₂ COOC ₈ H ₁₇ ) ₃ , (C ₈ H ₁₇ ) ₂ Sn
(SCH ₂ COOC ₈ H ₁₇ ) ₂ , (C ₄ H ₉ ) ₂ Sn
_{(SC 4 H 9) 2,} C 4 H 9 Sn (SC 4 H 9) 3 and the like.

As the organic tin chelate catalyst (B-2),
A tetravalent tin having an organic chelating agent bound by 2 mol chelate, for example, a compound of the formula

[0118]

[Chemical 12]

(In the above formula, A is the same or different and represents R ¹ , OR ² or SR ⁹ ,

[0120]

[Chemical 13]

Represents a chelate ring structure formed by an organic chelating agent. Incidentally, R ¹ , R ² and R ⁹ have the same meanings as described above. ) Can be used.

Preferred specific examples of the organic tin chelate catalyst (B-2) include, for example, monobutylbis (ethylacetoacetate) tin acetate, monobutylbis (acetylacetonato) tin octate, monobutylbis (ethylacetoacetate) tin laurate, bis (propylacetate). Acetate) tin diacetate, bis (propylacetoacetate) tin dilaurate, bis (acetylacetonato) tin diacetate, bis (acetylacetonato) tin dioctate, bis (acetylacetonato) tin dilaurate, bis (ethylacetoacetate) tin dioctate, Bis (ethylacetoacetate) tin diacetate, bis (ethylacetoacetate) tin dilaurate, bis (propylacetoacetate) tin dioctate, etc. It can gel.

In the thermosetting composition used in the present invention,
The mixing ratio of the organotin catalyst (B) is about 0.001 to 20 parts by weight, preferably about 0, per 100 parts by weight of the resin component (A) composed of the resin (A-1) or the mixed resin (A-2). ．
A range of 01 to 15 parts by weight is suitable.

When the organotin catalyst (B) is less than the above range, the low temperature curability is deteriorated. On the other hand, when it exceeds the above range, further low temperature curability is not obtained, and the finished appearance and durability of the cured product are not obtained. It is not preferable because it decreases.

Organic Solvent (C) The organic solvent (C) in the curable coating composition used in the present invention is a component which dissolves or disperses the components (A) and (B). Examples of the organic solvent (C) include the above (A)
As long as it can dissolve or disperse the component (B), it can be appropriately selected and used from conventional organic solvents without particular limitation.

Specific examples of the organic solvent (C) include aromatic hydrocarbons such as toluene and xylene, acetone,
Examples thereof include ketone systems such as methyl ethyl ketone and methyl isobutyl ketone, ester systems such as ethyl acetate, propyl acetate and butyl acetate, and alcohol systems such as ethylene glycol monobutyl ether.

The organic solvent (C) is blended so that the solid content of the curable coating composition is usually in the range of about 10 to 99% by weight.

In the curable coating composition used in the present invention, in addition to the components (A) to (C) described above, if necessary, an extender pigment, an ultraviolet absorber, an ultraviolet stabilizer, a fluidity modifier and other components. Additives such as paints can be added.

The curable coating composition used in the present invention is
It is used as a coating composition for a colored base coat by further mixing a color pigment in addition to the components (A) to (C) described above.

Examples of the color pigment include quinacridone-based organic pigments such as quinacridone red, azo-based pigments such as pigment red, and phthalocyanine-based pigments such as phthalocyanine blue and phthalocyanine green; inorganic powder pigments such as titanium oxide and carbon black; aluminum. flake,
Inorganic flake pigments such as nickel flakes, copper flakes, brass flakes, chrome flakes, pearl mica, colored pearl mica and the like can be mentioned.

Further, the curable coating composition used in the present invention can be used as it is as a coating composition for a clear top coat. In addition, the above-mentioned coloring pigment may be added to the clear topcoat coating composition, if necessary, to such an extent that the previously applied colored base coat is not completely hidden.

Next, the method of forming the top coating film of the present invention will be described.

The method of the present invention is a method for forming a topcoat coating film in which a colored basecoat and a clear topcoat are sequentially formed on a material, and one or both of the colored basecoat and the clear topcoat are topcoat paint compositions. It is formed by the curable coating composition used as.

In particular, the curable coating composition is acid resistant,
Since it is possible to form a coating film having excellent scratch resistance and the like, it is preferably used for a clear top coat. Further, the composition has excellent low temperature curability.

The method of the present invention is particularly suitable as a method for forming a top coat film for automobiles, home electric appliances, building materials and the like.

The method of forming the top coating film of the present invention is a coating system known in the fields of automobile industry, home appliance industry, building materials and the like, for example, 2 coat 1 bake method or 2 coat 2 bake of colored base coat / top clear coat. A method of finishing with a method or the like, a method of finishing colored base coat / top clear coat / top clear coat with 3 coat 1 bake system or 3 coat 2 bake system, etc. can be applied.

Of these methods, the method of finishing by the two-coat one-bake method is particularly preferable. Hereinafter, as a typical example, a coating method by the two-coat one-bake system using the curable coating composition for a clear top coat will be described.

First, the coating composition for a colored base coat is usually applied onto the above-mentioned material by spray coating.

The coating composition for a colored base coat is as follows:
A composition in which a color pigment is added to the curable coating composition or a coating composition for a colored base coat known per se for automobiles is used.

Examples of the known colored base coat coating composition include acrylic resin / amino resin system, alkyd resin / amino resin system, polyester resin / amino resin system, acrylic resin / polyisocyanate system, alkyd resin / polyisocyanate. Examples of the coating composition include a curable composition such as a polyester resin, a polyester resin / polyisocyanate system, and the like, and a color pigment. Here, as the amino resin, it is particularly preferable to use a melamine resin or the like.

The form of the known coating composition for colored base coat is not particularly limited, and any form such as organic solvent solution type, non-aqueous dispersion type, aqueous solution type, water dispersion type, high solid type and the like can be used. Can be used.

As the equipment used for spray coating, a normal air spray gun, an airless spray gun, an air spray type electrostatic coating machine, an airless spray type electrostatic coating machine, a rotary atomizing type electrostatic coating machine, etc. Can be used.

The film thickness of the coating composition for a colored base coat is
After curing, it is preferably in the range of about 10 to 30 μm.

After coating the coating composition for a colored base coat, the coating composition is left to stand at room temperature for several minutes or forcedly dried at a temperature in the range of about 50 to 80 ° C. for several minutes, and then the curable coating composition Clear Apply the topcoat coating composition.

The coating method and coating equipment for the clear topcoat coating composition may be the same as those for the colored basecoat coating composition.

The film thickness of the clear topcoat coating composition is preferably in the range of about 20 to 80 μm after curing.

Next, both the colored base coat and the clear top coat are heat-cured at the same time. It is suitable that the heating conditions are usually about 100 to 180 ° C. and about 10 minutes to 2 hours.

[0148]

EFFECTS OF THE INVENTION According to the method for forming a top coating film of the present invention, by using a specific curable coating composition as a top coating composition, particularly, low temperature curability, finished appearance, acid resistance,
A coating film having excellent scratch resistance, weather resistance, etc. can be formed.

[0149]

EXAMPLES Hereinafter, production examples, examples and comparative examples will be described.
The present invention will be described more specifically.

Production Example of Acrylic Resin (1) Using a reaction vessel equipped with a reflux device and a stirring device, 150 g of methacryloxypropyltrimethoxysilane, 3,4-
Epoxy cyclohexyl methyl methacrylate 220
g, 232 g of hydroxyethyl acrylate, 200 g of cyclohexylmethyl acrylate, 198 g of butyl methacrylate and 10 g of azoisobutyronitrile were added dropwise to 1,000 g of xylene at 110 ° C., and the mixture was reacted for 5 hours to give a number average molecular weight of 10,000. Acrylic resin (about 11 epoxy groups in one molecule, hydroxyl value = 112
And containing about 19 alkoxysilyl groups).

Production Example of Acrylic Resin (2) Using a reaction vessel equipped with a reflux device and a stirrer, 150 g of methacryloxypropyltrimethoxysilane, 3,4-
Epoxy cyclohexyl methyl methacrylate 220
g, 263 g of hydroxyethyl acrylate, 170 g of cyclohexylmethyl acrylate, 169 g of butyl methacrylate and 10 g of azoisobutyronitrile were added dropwise to 1,000 g of xylene at 110 ° C., and the mixture was reacted for 5 hours, and then succinic anhydride at 80 ° C. After adding 28 g and reacting for 2 hours, an acrylic resin having a number average molecular weight of 10,000 (containing about 11 epoxy groups and about 19 alkoxysilyl groups in one molecule, a hydroxyl value of 112 and an acid value of 1
5.6) was produced.

Production Example of Epoxy Group-Containing Resin (3) Using a reaction vessel equipped with a reflux device and a stirrer, 3,4-
Epoxy cyclohexyl methyl methacrylate 400
g, 600 g of butyl methacrylate and 10 g of azoisobutyronitrile were added to xylene 1.00 at 110 ° C.
It was added dropwise to 0 g and reacted for 5 hours to give a number average molecular weight of 1
10,000 acrylic resins (about 2 epoxy groups per molecule)
Containing 0).

Production Example of Epoxy Group-Containing Resin (4) Using a reaction vessel equipped with a reflux device and a stirring device, 284 g of glycidyl methacrylate and 35 of butyl methacrylate were used.
A mixture of 8 g, 358 g of cyclohexylmethyl acrylate and 10 g of azoisobutyronitrile was added dropwise to 1,000 g of xylene at 110 ° C. and reacted for 5 hours to obtain an acrylic resin having a number average molecular weight of 10,000 (epoxy group in one molecule. Containing about 20).

Production Example of Acrylic Resin (5) Using a reaction vessel equipped with a reflux device and a stirrer, 232 g of hydroxyethyl acrylate, 384 g of cyclohexylmethyl acrylate, 384 g of butyl methacrylate.
And a mixture of 10 g of azoisobutyronitrile at 110 ° C.
Was added dropwise to 1,000 g of xylene and reacted for 5 hours to produce an acrylic resin having a number average molecular weight of 10,000 (hydroxyl value = 112).

Production Example of Acrylic Resin (6) Using a reaction vessel equipped with a reflux device and a stirrer, 232 g of hydroxyethyl acrylate, 384 g of cyclohexylmethyl acrylate, 384 g of butyl methacrylate.
And a mixture of 10 g of azoisobutyronitrile at 110 ° C.
Xylene of 1,000 g, and after reacting for 5 hours, 28 g of succinic anhydride was added at 80 ° C. and reacted for 2 hours to obtain an acrylic resin having a number average molecular weight of 10,000 (hydroxyl value = 112, acid Value = 15.6) was produced.

Production Example of Epoxy Group-Containing Resin (7) Using a reaction vessel equipped with a reflux device and a stirrer, 3,4-
Epoxy cyclohexyl methyl methacrylate 400
g, 232 g of hydroxyethyl acrylate, 184 g of butyl methacrylate, 184 g of cyclohexylmethyl acrylate, and 10 g of azoisobutyronitrile were added dropwise to 1,000 g of xylene at 110 ° C., and the mixture was reacted for 5 hours to give a number average molecular weight of 10,000. Acrylic resin (containing about 20 epoxy groups in one molecule, hydroxyl value =
112) was produced.

Production Example of Acrylic Resin (8) Using a reaction vessel equipped with a reflux device and a stirring device, 243 g of methacryloxypropyltrimethoxysilane, 232 g of hydroxyethyl acrylate, 263 g of cyclohexylmethyl acrylate, 262 g of butyl methacrylate.
And a mixture of 10 g of azoisobutyronitrile at 110 ° C.
Xylene of 1,000 g and reacted for 5 hours to obtain an acrylic resin having a number average molecular weight of 10,000 (containing about 30 alkoxysilyl groups in one molecule, a hydroxyl value of 1
12) was produced.

Production Example of Acrylic Resin (9) Using a reaction vessel equipped with a reflux device and a stirrer, 243 g of methacryloxypropyltrimethoxysilane, 20 g of acrylic acid, cyclohexylmethyl acrylate 368
g, 369 g of butyl methacrylate and 10 g of azoisobutyronitrile were added to xylene 1.00 at 110 ° C.
It was added dropwise to 0 g and reacted for 5 hours to give a number average molecular weight of 1
10,000 acrylic resins (containing about 30 alkoxysilyl groups in one molecule, acid value = 15.6) were produced.

Production Example of Acrylic Resin (10) Using a reaction vessel equipped with a reflux device and a stirrer, 243 g of methacryloxypropyltrimethoxysilane, 232 g of hydroxyethyl acrylate, 20 g of acrylic acid, 253 g of cyclohexylmethyl acrylate, 252 g of butyl methacrylate and Azoisobutyronitrile 10g
The mixture was added dropwise to 1,000 g of xylene at 110 ° C. and reacted for 5 hours to obtain an acrylic resin having a number average molecular weight of 10,000 (containing about 30 alkoxysilyl groups in one molecule, hydroxyl value = 112, acid Value = 15.6) was produced.

Production Example of Acrylic Resin (11) Using a reaction vessel equipped with a reflux device and a stirrer, 80 g of acrylic acid and 460 cyclohexylmethyl acrylate were used.
g, 460 g of butyl methacrylate and 10 g of azoisobutyronitrile were added to xylene 1.00 at 110 ° C.
It was added dropwise to 0 g and reacted for 5 hours to give a number average molecular weight of 1
10,000 acrylic resins (acid value = 62) were produced.

Production Example of Reactive Silicon Group-Containing Resin (a) "Colcoat ES40" 530 g "Colcoat company, trade name, the same as hereinafter, 1 to 10 tetramer of tetraethyl silicate, average about 5 mer" Benzyl alcohol 470 g Tris 200 g of a mixture of 0.1 g of (acetylacetonato) aluminum was removed at 160 ° C. for 6 hours to obtain a reactive silicon group-containing resin (a). This product has 6 out of 12 ethoxy groups on average in one molecule.

[0162]

Embedded image

Is replaced by.

Clear top coat coating composition (a-
1) to (a-39) Production A coating composition for a clear top coat was produced based on the blending ratio (solid content) shown in Table 1.

Colored base coat coating composition (b-1)
~ And (b-5) Production Based on the blending ratio (solid content) described in Table 2, a colored base coat coating composition was produced.

[0166]

[Table 1]

[0167]

[Table 2]

[0168]

[Table 3]

[0169]

[Table 4]

[0170]

[Table 5]

[0171]

[Table 6]

[0172]

[Table 7]

[0173]

[Table 8]

[0174]

[Table 9]

In Tables 1 and 2, * 1 to * 5 have the following meanings.

* 1 ERL-4221: Union Carbide, trade name,
Alicyclic diepoxy compound * 2: the above-mentioned reactive silicon group-containing resin (a): phenyltrimethoxysilane * 3 Melamine resin: Uban 20SE (trade name, manufactured by Mitsui Toatsu Co., Ltd., butylated melamine resin, solid content 60) % By weight) * 4 Aluminum paste: Alpaste 4919 (trade name, manufactured by Toyo Aluminum Co., Ltd., aluminum flakes, solid content 65% by weight) * 5: A combination of two or three kinds.

Preparation of material [Electric No. 940
0 "(trademark, manufactured by Kansai Paint Co., Ltd., an epoxy resin-based cationic electrodeposition coating) is applied to a cured film thickness of 25 μm, heat-cured at 170 ° C. for 30 minutes, and then“ ES Primer Surfacer TP-37 "
(Trade name, manufactured by Kansai Paint Co., Ltd., polyester resin /
Cured melamine resin-based intermediate coating for automobiles)
It was coated so as to have a thickness of 0 μm, and cured by heating at 140 ° C. for 30 minutes. Next, the coating film was water-polished with # 400 sandpaper, drained and dried, and the coated surface was wiped with petroleum benzine as a material.

Example 1 Coating by a two-coat one-bake system was performed by the following steps.

Colored base coat coating composition (b-1)
Xylol paint viscosity 14 seconds (Ford Cup No.
A coating material adjusted to 4, 20 ° C., which has the same meaning below) was spray-coated on the prepared material so that the cured film thickness was about 15 μm to form a colored base coat on the material.

Next, after the colored base coat was allowed to stand for 3 minutes, the clear top coat coating composition (a-1) was adjusted to a coating viscosity of 25 seconds with xylol to give a cured film thickness of about 40 μm. Was spray coated onto the colored base coat to form a clear top coat.

Then, both the above-mentioned colored base coat and clear top coat coatings were simultaneously heat-cured at 120 ° C. for 30 minutes to form an overcoat coating.

Examples 2 to 41 and Comparative Examples 1 and 2 Using the coating composition for colored base coat and the coating composition for clear top coat described in Table 2, the same procedure as in Example 1 was carried out according to the 2 coat 1 bake method. Painting was performed to form a top coating film.

Next, finish properties (appearance, gloss, sharpness) and coating film performance tests were conducted on the top coating films formed in the above Examples and Comparative Examples.

Appearance: The presence or absence of abnormal surface conditions (glint, tinge, cracks, peeling, opacity (smudge)) was examined.

Gloss: The 60 ° specular reflectance (%) was measured.

Image clarity: Measured using a "PGD-IV type meter" (produced by Japan Color Research Laboratory, image clarity measuring instrument). The larger the value, the better the sharpness.

Solvent resistance: The coated surface was wiped 10 times with gauze soaked with xylol, and then the coated surface was observed and evaluated according to the following criteria.

◯ indicates that there is no change, Δ indicates that scratches are noticeable on the coated surface, and x indicates that the coated surface swells and tends to be whitened.

Adhesion: about 1.5 m with a knife on the coated surface
Make 11 vertical and horizontal cuts with a width of m. Next, a cellophane adhesive tape having a width of 24 mm was brought into close contact with the adhesive tape, and the number of adhered streaks remaining when strongly peeled off was examined. The evaluation criteria are as follows.

◯ indicates that the remaining number is 100, and Δ indicates that the remaining number is 9.
9 to 95, and x indicates that the remaining number is 94 or less, respectively.

Scratch resistance: It was examined by using a dyed product friction fastness tester (manufactured by Daiei Kagaku Seiki Seisakusho). Kneading polishing powder (Dharma cleanser) with water and placing it on the coated surface, holding it on the tester terminal and applying a load of 0.5 kg, 25
Rub back and forth, and evaluated based on the following criteria.

⊚ indicates that there is no change as compared with the initial gloss, ◯ indicates slight glossiness compared with the initial glossiness, and Δ indicates glossiness compared with the initial glossiness. That is, x indicates that gloss was remarkably generated as compared with the initial gloss.

Acid resistance: 0.4 cc of 40% by weight sulfuric acid water was dropped on the coated surface, dried at 75 ° C. for 15 minutes and washed with water,
The depth (μm) of the dropped sulfuric acid trace (etching) was measured.

Weather resistance: QUV weather meter (UV fluorescent lamp "No. QFS-40, U
V-B ", wavelength range 320 to 280 nm), the degree of coating film deterioration was observed after repeating a cycle of irradiation (15 minutes) and condensation (15 minutes) at a temperature of 40 to 70 ° C. for 2000 hours.

The test results are shown in Table 3.

[0196]

[Table 10]

[0197]

[Table 11]

[0198]

[Table 12]

[0199]

[Table 13]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryo Isozaki 4-17-1, Higashihachiman, Hiratsuka City, Kanagawa Kansai Paint Co., Ltd.

Claims (6)

[Claims] 1. A method for forming a topcoat coating film comprising a colored base coat and a clear top coat sequentially formed on a material, wherein the colored base coat and / or the clear top coat are (A) (i) an epoxy group and (ii) a reaction. -Containing silicon group and (iii) a hydroxyl group and / or a carboxyl group in the same molecule as an essential functional group component (A-1), or at least the functional group component (i) to (iii) above. A mixed resin (A-2), (B), which is a mixture of two or more kinds of resins each containing one kind of resin, and in which the functional group components (i) to (iii) are all present. ) Organotin catalyst,
And (C) a curable coating composition containing an organic solvent as an essential component. 2. A method for forming a topcoat coating film, comprising forming a colored base coat on a material, then forming a clear top coat on the surface of the base coat without curing, and then curing both coating films by heating to form 2 coat 1. The method for forming a topcoat coating film according to claim 1, wherein the method is a baking method. 3. The method for forming a topcoat coating film according to claim 1, wherein both the colored base coat and the clear top coat are the curable coating composition. 4. The method for forming a topcoat coating film according to claim 1, wherein the colored base coat is a coating composition in which a color pigment is mixed with an acrylic resin / amino resin-based curable composition. 5. An organotin catalyst (B) has the following general formula (1) (R ¹ ) _n Sn (OR ² ) _4-n (1) (wherein R ¹ is the same or different and has a carbon number 1 to 20 monovalent hydrocarbon groups, R ² are the same or different,
A monovalent hydrocarbon group having 1 to 20 carbon atoms, -COCH = CH
COOR ¹ group, or And n is 0 or an integer of 1 to 3. The method for forming a topcoat film according to claim 1, which is a compound represented by the formula (1). 6. The method for forming an overcoat film according to claim 1, wherein the organotin catalyst (B) is an organotin chelate catalyst.