JPH0910686A - Formation of double-layered coating film - Google Patents

Abstract

PURPOSE: To provide a method fit to coat the outer plate of a car body and giving a coating film excellent in acid, scuffing and wear resistances. CONSTITUTION: The top of a body to be coated is coated with a base coating compsn. and further coated with a top coating compsn. and the compsns. are separately or simultaneously cured to form the objective double-layered coating film. The top coating compsn. contains a blend of a compd. having plural hydrosilyl groups with a compd. having plural alkenyl groups or a compd. having plural hydrosilyl groups and plural alkenyl groups and a catalytic amt. of a hydrosilylation catalyst. The base coating compsn. contains a crosslinking agent which does not hinder the hydro-silylation reaction of the top coating compsn. and a functional resin capable of reacting with the crosslinking agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a multi-layer coating film, and more particularly to a method for forming a multi-layer coating film which is excellent in acid resistance and scratch resistance and which is suitable for outer panels of automobile bodies.

For the finish coating of automobiles, in particular passenger cars, a transparent topcoat is applied on top of a base coat containing pigments. The role of the top coat is mainly to improve the appearance of the coating film, but for that purpose, excellent weather resistance is required to maintain high gloss for a long period of time. Further, the top coat is required to have excellent scratch resistance against car wash brushes, chemical resistance against acids and alkalis, and easy removal of attached tar-like substances and dusts.

For this purpose, a solvent-type topcoat composition prepared by blending a melamine resin or a polyisocyanate compound with a hydrosilyl group-containing acrylic polymer is currently used. However, when a melamine resin is used as a curing agent, there is a problem that weather resistance due to the triazine skeleton of melamine and durability against acid rain, which has been a problem in recent years, are not satisfactory. Further, when a polyisocyanate compound is used as a curing agent, there are problems such as toxicity, yellowing of the coating film and deterioration of weather resistance.
Such problems also apply to overcoats applied over topcoats.

By the way, recently, from the viewpoint of environmental protection and resource saving, regulations on organic solvent type coatings are becoming strict. However, it is difficult to obtain the appearance (transparency, gloss, etc.) required for this purpose with powder coatings and water-based coatings that do not use organic solvents.

As a method for solving these problems, there has been proposed a curable resin composition having a curing mechanism of addition of a hydrosilyl group to a carbon-carbon double bond (hydrosilylation reaction) (see, for example, Japanese Patent Application Laid-Open No. Hei 10 (1999) -242242). 3-277645, 5-28
No. 7206). In the curing reaction of these compositions, since the newly formed bond is a chemically extremely stable silicon-carbon bond, the weather resistance and the acid resistance are high, and the cohesive force of the hydrosilylation curing agent is low. It can be designed as solvent-free or ultra-high solid type paint. Therefore, by using these compositions instead of the conventional solvent-based topcoat or overcoat composition, for example, while further improving the coating performance of a multilayer coating for finish coating of automobile bodies, It can be expected to eliminate or significantly reduce the release of organic solvents into the atmosphere. However, when such a top coat composition is applied onto a base coat using a conventional melamine resin as a curing agent by a wet-on-wet method and baking is performed, the curing reaction does not proceed sufficiently, so that it is sufficient. It has been found that there is a problem that excellent acid resistance and scratch resistance cannot be obtained.

Therefore, an object of the present invention is to provide a method for forming a multi-layer coating film which is excellent in acid resistance and scratch resistance and which is suitable for coating automobile body outer panels.

[0007]

As a result of intensive studies in view of the above problems, the inventors of the present invention coated a base coat composition on an object to be coated, and then coated a top coat composition containing a hydrosilyl group thereon. When a multilayer coating film is formed by curing the both separately or simultaneously, the base coat composition has a good coating hardness by using a crosslinking agent that does not inhibit the curing reaction of the top coat composition. At the same time, they have found that a coating film having excellent acid resistance and scratch resistance can be obtained, and have conceived the present invention.

That is, the method for forming a multilayer coating film of the present invention comprises coating a base coat composition on an object to be coated, coating a top coat composition thereon, and curing the both separately or simultaneously. In forming a multilayer coating film, the topcoat composition comprises (a) a blend of a compound having a plurality of hydrosilyl groups and a compound having a plurality of alkenyl groups, or a plurality of hydrosilyl groups and a plurality of alkenyl groups. A compound having both, and (b) a catalytic amount of a hydrosilylation catalyst, the base coat composition, (c) a cross-linking agent that does not inhibit the hydrosilylation reaction of the top coat composition, and (d) the cross-linking agent. It is characterized by containing a functional resin capable of reacting with.

The present invention is described in detail below. [1] Base coat composition The base coat composition used in the present invention comprises (1) a crosslinking agent,
It consists of (2) a functional resin, and (3) a solvent, (4) a pigment, and (5) other additives which are added as necessary.

(1) Cross-linking Agent The cross-linking agent of the base coat composition may be any one that does not interfere with the hydrosilylation reaction utilized in the curing reaction of the top coat composition described below. As such a cross-linking agent, an amino resin, a block polyisocyanate compound,
Examples include curing agents for epoxy resins.

(I) Amino Resin As the amino resin, for example, a condensate obtained by reacting one or a mixture of two or more amino compounds such as melamine, urea and benzoguanamine with formaldehyde, and a condensate of methanol, butanol, etc. Alkyl etherified melamine resin obtained by reacting the lower alcohol of The number average molecular weight of such an alkyl etherified melamine resin is preferably 400 to 1200.

In particular, an average of 0 to 1 per triazine ring
Amino resins having one imino group are preferred, and amino resins having an average of 0 to 0.2 imino groups are particularly preferred. An alkyl ether group or the like is bonded to the portion other than the imino group. When the average number of imino groups per triazine ring exceeds 1, the hydrosilylation reaction of the topcoat composition is hindered and the coating film hardness is reduced. The average number of imino groups per triazine ring is ¹ H-N with the weight ratio of carbon, hydrogen and nitrogen determined by elemental analysis.
Calculated from NH / -NCH ₂ OR a molar ratio obtained from MR.

(Ii) Blocked Polyisocyanate Compound Examples of the blocked polyisocyanate compound include aliphatic polyfunctional isocyanates such as hexamethylene diisocyanate (HMDI) and isophorone diisocyanate (IPD).
Alicyclic polyfunctional isocyanates such as I), diphenylmethane-4,4'-diisocyanate (MDI) and hydrogenated MDI
And the like, in which the functional groups of the polyisocyanate compound are partially or completely blocked.

(Iii) Curing Agent for Epoxy Resin Examples of the curing agent for epoxy resin include chain aliphatic polyamines such as diethylenetriamine, triethylenetetraamine and ethylaminopropylamine, cycloaliphatic polyamines, aliphatic polyamine adducts, keimine, Modified aliphatic polyamines, polyamidoamines, aromatic amines, aromatic modified amines, aromatic polyamines such as diaminodiphenylmethane, aromatic modified polyamines, tertiary amine curing agents, mercaptan curing agents, acid anhydride curing agents, Copolymers having acid anhydride groups such as ethylene-maleic anhydride copolymers, compounds having phenolic hydroxyl groups such as phenol resin initial condensation products, dicyandiamide, silicon trifluoride-
Examples thereof include silicon trifluoride-based composites such as amine complex compounds. Among these curing agents, dicyandiamide, diaminodiphenylmethane, and silicon trifluoride-amine complex compound are preferable.

(2) Functional Resin The functional resin used in the present invention is a resin containing at least two hydroxyl groups in one molecule as functional groups, which are reaction sites with the above-mentioned cross-linking agent. Examples thereof include acrylic resin, hydroxyl group-containing polyester resin, epoxy resin, hydroxyl group-containing fluororesin and hydroxyl group-containing amide resin. Among these, hydroxyl group-containing acrylic resin, epoxy resin and hydroxyl group-containing polyester resin are preferable. Such a functional resin can be used in both aqueous and organic solvent types.

(I) Hydroxyl group-containing acrylic resin The hydroxyl group-containing acrylic resin is hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate,
Having a hydroxyl group-containing (meth) acrylic acid ester-based monomer such as hydroxybutyl (meth) acrylate and N-methylolacrylamide, and a carboxyl group such as (meth) acrylic acid, crotonic acid, itaconic acid, fumaric acid, and maleic acid Ethylenically unsaturated monomers and methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-acrylate
Obtained by polymerizing at least one kind of (meth) acrylic acid alkyl ester such as dodecyl (however, at least one kind of monomers to be used must contain a hydroxyl group) by a usual method. You can In addition, the term "(meth) acrylic acid" used in this specification means acrylic acid or methacrylic acid.

Further, in addition to the above-mentioned monomers, copolymerizable (meth) acrylonitrile, styrene, (meth) acrylic acid amide, dimethylacrylamide, N, N-dimethylpropylacrylamide, N-butoxymethylacrylamide, N-methylol ( (Meth) acrylamide, diacetone acrylamide, etc. can be blended.

The number average molecular weight of the hydroxyl group-containing acrylic resin is
It is preferably 1,800 to 100,000. Number average molecular weight is
If it is less than 1,800, the cross-linking in the coating film is not sufficient, so that the acid resistance and scratch resistance are low. On the other hand, if it exceeds 100,000, the viscosity of the coating material becomes high and the coating film appearance excellent in smoothness cannot be obtained. A more preferable number average molecular weight is 5,000 to 20,000.

The hydroxyl value of the hydroxyl group-containing acrylic resin is 20 to
It is preferably 200. When the hydroxyl value is less than 20, the adhesion of the coating film and the curability of the coating material are low, while when it exceeds 200, the water resistance and acid resistance are deteriorated by the residual hydroxyl groups. A more preferable hydroxyl value is 40 to 100.

The acid value of the hydroxyl group-containing acrylic resin is 5 to
It is preferably 150. If the acid value is less than 5, the coating film will not be sufficiently cured, and if it exceeds 150, the storage stability of the coating composition will decrease and the curing rate will increase, resulting in a poor coating appearance. A more preferable acid value is 5 to 80.

When the hydroxyl group-containing acrylic resin is made aqueous, it is partially or completely neutralized with a volatile base. Ammonia or amine is preferred as the volatile base. Particularly preferred amines are monopropylamine, monobutylamine, diethylamine, dibutylamine, triethiamine, tributylamine, monoethanolamine, ethylmonoethanolamine, dimethylaminoethanol, 2-amino-2-methyl-1-propanol, cyclohexyl. Examples include primary amines such as amines, morpholine and piperidine, secondary amines and tertiary amines.

(Ii) Hydroxyl Group-Containing Polyester Resin The hydroxyl group-containing polyester resin is obtained by polycondensing (esterifying) a polyhydric alcohol and a polybasic acid or an anhydride thereof.

As the polyhydric alcohol, ethylene glycol, propylene glycol, butylene glycol, 1,
6-hexanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, triethylene glycol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, etc.
It can be used in combination of more than one kind.

Examples of the polybasic acid or its anhydride include phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, tetrahydrophthalic anhydride and hexahydrophthalic anhydride. Examples thereof include acids, maleic anhydride, fumaric acid, itaconic acid, and mellitoic anhydride, and these can be used in combination of two or more kinds.

The number average molecular weight of the hydroxyl group-containing polyester resin is preferably 200 to 10,000. Number average molecular weight is
If it is less than 200, the cross-linking in the coating film is not sufficient, so that the acid resistance and scratch resistance are low, while if it exceeds 10,000, the viscosity of the coating material is high and the coating film appearance excellent in smoothness cannot be obtained. A more preferable number average molecular weight is 300 to 6,000.

The hydroxyl value of the hydroxyl group-containing polyester resin is
It is preferably 50 to 350. When the hydroxyl value is less than 50, the adhesiveness of the coating film and the curability of the coating material are low, while when it exceeds 350, the water resistance and acid resistance are reduced due to the remaining hydroxyl groups. A more preferable hydroxyl value is 70 to 280.

The acid value of the hydroxyl group-containing polyester resin is preferably 3 to 100. If the acid value is less than 3, the coating film will not be sufficiently cured, and if it exceeds 100, the storage stability of the coating composition will decrease and the curing rate will increase, resulting in a poor coating appearance. A more preferable acid value is 5 to 50.

When the hydroxyl group-containing polyester resin is water-based, the hydroxyl group-containing polyester resin may be partially or completely neutralized with the above-mentioned volatile base.

(Iii) Epoxy Resin Examples of the epoxy resin include various bisphenol type epoxy resins. The number average molecular weight of the hydroxyl group-containing epoxy resin is preferably 300 to 5,000. If the number average molecular weight is less than 300, the cross-linking in the coating film is not sufficient, so acid resistance and scratch resistance are low, while if it exceeds 5,000, the viscosity of the coating becomes high and a coating film with excellent smoothness etc. can be obtained. Absent.

The epoxy equivalent of the epoxy resin is 200 to 2,000.
It is preferably 0. If the epoxy equivalent is less than 200, the chemical resistance and the curability of the paint are low, while if it exceeds 2,000, the water resistance is reduced. More preferable epoxy equivalent is 300-
It is 1,500.

When the epoxy resin is aqueous, the epoxy resin may be partially or completely neutralized with the above-mentioned volatile base.

The mixing ratio of the cross-linking agent and the functional resin is
Crosslinking agent in solid content conversion is 10 to 50% by weight, preferably 15 to 40
% By weight, functional resin 90 to 50% by weight, preferably
85-60% by weight. When the cross-linking agent is less than 10% by weight (when the functional resin is more than 90% by weight), the acid resistance and the scratch resistance are low because the crosslinking in the coating film is insufficient. On the other hand, if the amount of the cross-linking agent exceeds 50% by weight (when the amount of the functional resin is less than 50% by weight), the storage stability of the coating composition decreases and the curing speed increases, resulting in poor coating film appearance.

(3) Solvent When the base coat composition is used as a solvent type paint, an aliphatic hydrocarbon such as Solvesso 100 and Solvesso 150, an aromatic hydrocarbon such as toluene and xylene, an ester such as ethyl acetate and butyl acetate. , Methyl ethyl ketone,
Solvents of ketones such as methyl isobutyl ketone, acetone and isophorone can be used alone or in combination. When used as a water-soluble or water-dispersible aqueous coating material, ethers such as carbitol acetate and butyl carbitol, methanol, butanol, isopropanol, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, etc. Hydrophilic organic solvents such as alcohols can be used in combination with water.

(4) Pigment As the pigment, carbon black, titanium dioxide, lead white, graphite, zinc sulfide, zinc oxide, chromium oxide, zinc chromate, strontium chromate, barium chromate, yellow nickel titanium, yellow chromium titanium , Iron oxide, yellow iron oxide, red iron oxide, black iron oxide, phthalocyanine blue, phthalocyanine green, ultramarine blue,
Quinacridones, indanthrone, isoindolinone,
Perylene, anthrapyrimidine, benzimidazolone,
Coloring pigments such as cadmium sulfide and diketopyrrolopyrrole,
Extender pigments such as calcium carbonate, magnesium carbonate, barium sulfate, silicic acid, silicates, aluminum oxide hydrate, calcium sulfate, and various metal foils, titanium mica, cobalt sulfide, manganese sulfide, titanium sulfide, foil phthalocyanine blue. There are metallic or bright pigments such as. Base coat compositions are broadly classified into metallic and solid types depending on the type of pigment. The weight ratio of pigment / resin solid content is preferably 0.01 / 1 to 1/1,
It is more preferably 0.03 / 1 to 0.9 / 1.

(5) Other Additives In the base coat composition, if necessary, an acid catalyst, a benzophenol-based ultraviolet absorber, a phenol-based and sulfide-based antioxidant, a surface adjustment of silicone, an organic polymer, etc. Agents, anti-sagging agents, thickeners and the like can be added in an amount of about 0.1 to 5% by weight.

[2] Topcoat composition Topcoat composition used in the present invention (preferably transparent)
Is (1) a blend of a compound having a plurality of hydrosilyl groups (hereinafter referred to as “hydrosilyl group-containing compound”) and a compound having a plurality of alkenyl groups (hereinafter referred to as “alkenyl group-containing compound”), or a plurality of A compound having both a hydrosilyl group and a plurality of alkenyl groups (hereinafter referred to as "self-crosslinking resin"), and (2) a hydrosilylation catalyst. This composition is easily crosslinked into a cured coating film by a reaction (hydrosilylation reaction) in which Si—H bonds are added to carbon-carbon double bonds in a molecule or in a molecule.

(1) Blend of Hydrosilyl Group-Containing Compound and Alkenyl Group-Containing Compound (i) First Hydrosilyl Group-Containing Compound The first hydrosilyl group-containing compound includes (i) the general formula:

Embedded image (However, R ¹ is an alkyl group having 1 to 6 carbon atoms, a phenyl group or a phenethyl group, and R ² is a hydrogen atom or 1 to 1 carbon atoms.
An alkyl group of 6, a phenyl group or a phenethyl group,
a is a number of 2 to 200. ) And / or (b) an organohydrogenpolysiloxane having a structural unit represented by the formula (1) and containing at least two hydrosilyl groups in one molecule:

Embedded image (However, R ¹ is an alkyl group having 1 to 6 carbon atoms, a phenyl group or a phenethyl group, and R ² is a hydrogen atom or 1 to 1 carbon atoms.
An alkyl group of 6, a phenyl group or a phenethyl group,
b is a number from 1 to 30. ) Has a structural unit represented by
A homopolymer or a copolymer of a hydrogen polysiloxane macromonomer having at least one hydrosilyl group in one molecule and at least one (meth) acryloyloxyalkylene group in the middle or at the end of the siloxane skeleton (however, It is preferable to use) which does not include an alkenyl group.

Preferred specific examples of the organohydrogenpolysiloxane include compounds represented by the following structural formulas (3) to (5).

[0039]

Embedded image (However, R ³ and R ⁴ are an alkyl group having 1 to 6 carbon atoms, a phenyl group or a phenethyl group, d is a number of 0 to 100, and e is a number of 2 to 100). Structural unit-SiOR ³
R ³ -and -SiOR ⁴ H- may be randomly arranged, and the terminal group -SiR ³ R ³ R ³ may be bonded to the siloxane skeleton in any combination.

[0040]

Embedded image (However, R ³ and R ⁴ are an alkyl group having 1 to 6 carbon atoms, a phenyl group or a phenethyl group, and f and g are each a number of 0 to 100). Similar to the above structural formula (1), the structural units -SiOR ³ R ³ -and -SiOR ⁴ H- may be randomly arranged, and the terminal group -SiR ³ R ³ H may be any combination of siloxane skeletons. May be attached to.

[0041]

Embedded image (However, R ³ and R ⁴ are an alkyl group having 1 to 6 carbon atoms, a phenyl group or a phenethyl group, h is a number from 0 to 8, i is a number from 2 to 10, and (h + i) Is a number from 3 to 10.). Details of these organohydrogenpolysiloxanes are described in JP-A-3-277645.

Examples of the alkyl group having 1 to 6 carbon atoms in R ³ and R ⁴ include methyl group, ethyl group, propyl group and butyl group. From an industrial viewpoint, a methyl group and a propyl group are particularly preferable. The degree of polymerization of the organohydrogenpolysiloxane is defined by d to i, but the organohydrogenpolysiloxane having a degree of polymerization larger than the above range has high viscosity and poor workability, and
Poor compatibility with alkenyl components. In order to improve the compatibility, those containing a phenyl group as an organic group are preferable. Particularly preferred organohydrogenpolysiloxanes include methylphenylhydrogenpolysiloxane and methylpropylhydrogenpolysiloxane.

(Ii) Second Hydrosilyl Group-Containing Compound The second hydrosilyl group-containing compound is a homopolymer of a hydrogen polysiloxane macromonomer having a (meth) acryloyloxyalkylene group bonded in the middle or at the end of the siloxane skeleton or It is a copolymer. The (meth) acryloyloxyalkylene group is preferably a 3- (meth) acryloyloxypropyl group. Homopolymerization or copolymerization of the hydrogen polysiloxane macromonomer can be carried out by a known solution polymerization method. In addition,
Homopolymers or copolymers of hydrogen polysiloxane macromonomers (however, alkenyl groups are not included)
Details of the above are described in JP-A-7-11141.

Preferred specific examples of the hydrogen polysiloxane macromonomer include the following structural formulas (6) to (8)
And the like.

[0045]

Embedded image (However, R ³ is an alkyl group having 1 to 6 carbon atoms, a phenyl group or a phenethyl group, A is a 3- (meth) acryloyloxyalkylene group, j is a number of 0 to 20,
k is a number from 1 to 3 and l is a number from 0 to 10. ). However, the arrangement of each structural unit and terminal group is arbitrary.

[0046]

[Formula 10] (However, R ³ is an alkyl group having 1 to 6 carbon atoms, a phenyl group or a phenethyl group, A is a 3- (meth) acryloyloxyalkylene group, j is a number of 0 to 20,
k is a number from 1 to 3 and m is a number from 1 to 10. ). However, the arrangement of each structural unit and terminal group is arbitrary.

[0047]

[Formula 11] (However, A is a 3- (meth) acryloyloxyalkylene group, and R ³ and R ⁴ are an alkyl group having 1 to 6 carbon atoms, a phenyl group, a phenethyl group, or -OSi (R ³ ) ₂
H, R ⁵ is a hydrogen atom or —OSi (R ³ ) ₂ H, and n is a number from 1 to 10. ). Details of these hydrogen polysiloxane macromonomers are described in JP-A-4-16.
It is described in No. 9589. The term "(meth) acryloyl" used in the present specification means acryloyl or methacryloyl.

When the (meth) acryloyl group-containing hydrogen polysiloxane macromonomer is used as a copolymer, an ethylenically unsaturated monomer (not including an alkenyl group) is used as a monomer for copolymerization (however, it does not contain an alkenyl group). For example, it is preferable to use acrylic monomers and vinyl monomers). As the acrylic monomer, a (meth) acrylic acid ester (for example, methyl (meth) acrylate, (meth))
Ethyl acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate , 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, adduct of 2-hydroxyethyl (meth) acrylate and poly-ε-caprolactone, epoxy group-containing (meth) acrylic acid Ester (for example, glycidyl (meth) acrylate), (meth)
3-trimethoxysilylpropyl acrylate, 3-triethoxysilylpropyl (meth) acrylate, 3-dimethoxymethylsilylpropyl (meth) acrylate, (meth)
Acrylic acid-2-acrylamido-2-methylpropanesulfonic acid, acid phosphoxypropyl methacrylate,
Examples thereof include tributyltin (meth) acrylate, (meth) acrylamide, (meth) acryloyl cyanate, (meth) acrylic acid-2-isocyanatoethyl, and silicone macromonomer. Examples of vinyl monomers include styrene, α-methylstyrene, itaconic acid, maleic acid, vinyl acetate, allyl acetate, vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, and N. -Cyclohexylmaleimide, N-phenylmaleimide and the like can be mentioned.

In the homopolymer or copolymer of the hydrogen polysiloxane macromonomer (however, the alkenyl group is not included), the blending amount of the hydrogen polysiloxane macromonomer is 20 to 100% by weight, and the alkenyl group is contained. The amount of the copolymerization component (ethylenically unsaturated monomer) not to be blended is preferably 80 to 0% by weight. More preferably, the blending amount of the hydrogen polysiloxane macromonomer is 40 to 100% by weight, and the blending amount of the copolymerization component (excluding alkenyl groups) is 60 to 0% by weight. If the blending amount of the hydrogen polysiloxane macromonomer is less than 20% by weight (the blending amount of the copolymerization component is
If it exceeds 80% by weight), the crosslink density of the cured composition is low and sufficient scratch resistance and acid resistance cannot be obtained.

The number average molecular weight of the homopolymer or copolymer of the hydrogen polysiloxane macromonomer (provided that it does not contain an alkenyl group) is preferably 1,000 to 30,000. Further considering the curability of the cured coating,
The concentration of hydrosilyl groups in these polymers is 1 × 10 ^-3 m
It is preferably ol / g or more.

(Iii) Alkenyl Group-Containing Compound Examples of the alkenyl group-containing compound include alkenyl group-containing polyether resin, alkenyl group-containing acrylic resin, alkenyl group-containing polyester resin, alkenyl group-containing polycarbonate resin and alkenyl group-containing epoxy resin. Can be mentioned.

Alkenyl Group-Containing Polyether Resin The alkenyl group-containing polyether resin is obtained by ring-opening polymerization of an alkenyl group-containing 1,2-epoxy compound with an active hydrogen compound (water, monohydric or polyhydric alcohol) as an initiator. The polyethers obtained are preferred. For example, polyether obtained by ring-opening polymerization of allyl glycidyl ether with ethylene glycol as an initiator (number average molecular weight 1200,
Polyether having the following structural formulas (9) to (15) and physical properties obtained by ring-opening polymerization of vinylcyclohexane-1,2-epoxide with an iodine value of 212), butanol, allyl alcohol or propargyl alcohol as an initiator. (JP-A-4-23829).

[0053]

Embedded image (Number average molecular weight 450, iodine value 170).

[0054]

Embedded image (Number average molecular weight 820, iodine value 185).

[0055]

Embedded image (Number average molecular weight 890, iodine value 170).

[0056]

Embedded image (Number average molecular weight 980, iodine value 130).

[0057]

Embedded image (Number average molecular weight 780, iodine value 196).

[0058]

Embedded image (Number average molecular weight 750, iodine value 170).

[0059]

Embedded image (Number average molecular weight 430, iodine value 236).

Divinyl ether resins such as triethylene glycol divinyl ether and cyclohexane dimethanol divinyl ether are also included in the alkenyl group-containing polyether resin.

Alkenyl group-containing acrylic resin The alkenyl group-containing acrylic resin is obtained by homopolymerization of an alkenyl group-containing acrylic monomer or copolymerization with another acrylic monomer. Examples of the alkenyl group-containing acrylic monomer include allyl (meth) acrylate, 2-butenyl (meth) acrylate, 3-methyl-3-butenyl (meth) acrylate, and (meth) acrylic acid-3.
-Methyl-2-butenyl, cyclohexenyl methyl (meth) acrylate, 2-methyl-2-propenyl (meth) acrylate, 3-heptenyl (meth) acrylate, 4-hexenyl (meth) acrylate, methacrylic acid 2 Examples include a 1: 1 addition product of hydroxyethyl and vinylcyclohexene monoepoxide. The alkenyl group-containing acrylic monomer is, for example, a reaction of (meth) acrylic acid chloride and alkenyl alcohol, a transesterification reaction of alkyl (meth) acrylate and alkenyl alcohol,
It can be synthesized by an addition reaction of an isocyanate group-containing acrylic monomer and an alkenyl alcohol.

Other acrylic monomers that can be copolymerized with the alkenyl group-containing acrylic monomer include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylic acid 2 -
Ethylhexyl, lauryl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth)
2-Hydroxypropyl acrylate, (meth) acrylic acid
4-hydroxybutyl, an adduct of 2-hydroxyethyl (meth) acrylate and poly-ε-caprolactone, glycidyl (meth) acrylate, 3-trimethoxysilylpropyl (meth) acrylate, and (meth) acrylic acid 3 -Triethoxysilylpropyl, (meth) acrylic acid 3-dimethoxymethylsilylpropyl, (meth) acrylic acid 2-acrylamido-2-methylpropanesulfonic acid, acid phosphoxypropyl methacrylate, (meth) acrylic acid tributyltin, (meth ) Acrylamide, (meth) acryloyl isocyanate, 2-isocyanatoethyl (meth) acrylate, silicone macromonomers and the like. Further, within a range of 50% by weight or less, an ethylenically unsaturated monomer other than the acrylic monomer (for example, styrene,
α-methylstyrene, 2,4-diphenyl-4-methyl-1-pentene, itaconic acid, maleic acid, vinyl acetate, allyl acetate, vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxy Silane, N-cyclohexylmaleimide, N
-Phenylmaleimide, etc.) can also be copolymerized.

As another method for synthesizing the alkenyl group-containing acrylic resin, an addition reaction of a hydroxyl group-containing acrylic resin with an alkenyl isocyanate and / or an alkenyl group-containing carboxylic acid anhydride, an isocyanate group-containing acrylic resin and an alkenyl alcohol And the addition reaction of a carboxyl group-containing acrylic resin with an alkenyl group-containing epoxy, and the addition reaction of an epoxy group-containing acrylic resin with an alkenyl group-containing carboxylic acid.

The hydroxyl group-containing acrylic resin includes 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate. Poly-
Copolymerization of hydroxyl group-containing acrylic monomer such as an adduct with ε-caprolactone, the other acrylic monomer, and an ethylenically unsaturated monomer in the range of 50% by weight or hydroxyl group-containing It is obtained by polymerizing the acrylic monomer alone.

Examples of the alkenyl isocyanate include allyl isocyanate, (meth) acryloyl isocyanate, 2-isocyanatoethyl (meth) acrylate and the like.

Examples of the alkenyl group-containing carboxylic acid anhydride include itaconic anhydride, maleic anhydride, tetrahydrophthalic anhydride and the like.

The isocyanate group-containing acrylic resin is
Isocyanate group-containing acrylic monomers such as (meth) acryloyl isocyanate and (meth) acrylic acid 2-isocyanatoethyl, the above-mentioned other acrylic monomers, and an ethylenically unsaturated monomer in an amount of 50% by weight or less. It is obtained by copolymerizing with or by homopolymerizing an isocyanate group-containing acrylic monomer.

As alkenyl alcohol, allyl alcohol, vinyl alcohol, 3-buten-1-ol, 2-
(Allyloxy) ethanol, glycerin diallyl ether, cyclohexenemethanol, 3-methyl-2-butene
-1-ol, 3-methyl-3-butene-1-ol, 2-methyl
-3-butyn-2-ol, oleyl alcohol, crotyl alcohol, hydroxybutyl vinyl ether and the like can be mentioned.

The carboxyl group-containing acrylic resin is
Acrylic monomer having a carboxyl group such as (meth) acrylic acid and / or itaconic acid within a range of 50% by weight,
Whether to copolymerize a carboxyl group-containing ethylenically unsaturated monomer such as maleic acid with the above-mentioned other acrylic monomers and / or a blending amount of 50% by weight or less of an ethylenically unsaturated monomer Alternatively, it can be obtained by homopolymerizing a carboxyl group-containing acrylic monomer.

Examples of the alkenyl group-containing epoxies include glycidyl (meth) acrylate and allyl glycidyl ether. The epoxy group-containing acrylic resin is, for example, an epoxy group-containing acrylic monomer such as glycidyl (meth) acrylate, the above-mentioned acrylic monomer other than that, and an ethylenically unsaturated monomer having a blending amount of 50% by weight or less. It is obtained by copolymerizing with or by homopolymerizing an epoxy group-containing acrylic monomer.

Examples of the alkenyl group-containing carboxylic acid include allyl acetic acid, (meth) acrylic acid, 2-butenoic acid, 3-butenoic acid, crotonic acid, undecylenic acid and linoleic acid.

Alkenyl Group-Containing Polyester Resin The alkenyl group-containing polyester resin is easily produced by the polycondensation reaction of the above-mentioned alkenyl alcohol, a polyhydric alcohol and a polybasic acid. Polyhydric alcohols include ethylene glycol, propylene glycol, 1,6-
Hexane diol, diethylene glycol, neopentyl glycol, hydroxypivalic acid neopentyl glycol ester, trimethylol propane, dimethyl siloxane containing alcoholic hydroxyl groups at both ends and the like can be mentioned. As the polybasic acid, phthalic anhydride, isophthalic acid,
Examples thereof include terephthalic acid, adipic acid, azelaic acid, trimellitic acid and the like, and a monohydric alcohol or a monobasic acid may be partially used, if necessary.

As another method for synthesizing the alkenyl group-containing polyester resin, for example, the carboxyl group of the polyester resin obtained by the polymerization reaction of the above-mentioned polyhydric alcohol and polybasic acid and the above-mentioned alkenyl-group-containing epoxy compound are prepared. Examples thereof include an addition reaction and an addition reaction between a hydroxyl group of a polyester resin obtained by a polycondensation reaction of a polyhydric alcohol and a polybasic acid with an anhydride of the above-mentioned alkenyl isocyanate and / or alkenyl group-containing carboxylic acid.

Alkenyl Group-Containing Polycarbonate Resin An alkenyl group-containing polycarbonate resin is prepared by first reacting a difunctional polyol such as cyclohexanedimethanol with dimethyl carbonate, and then reacting pentaerythritol triallyl with terminal carbonate groups of the polycarbonate produced. It is obtained by reacting an alkenyl group-containing monoalcohol such as ether.

Alkenyl Group-Containing Epoxy Resin In addition to the above-mentioned epoxy group-containing acrylic resin, the alkenyl group-containing epoxy resin is, for example, an addition reaction of bisphenol A diglycidyl ether with the above-mentioned alkenyl group-containing carboxylic acid, an epi-bis type epoxy resin. It can be easily produced by an addition reaction between the hydroxyl group in the resin and the above-mentioned alkenyl isocyanate and / or alkenyl group-containing carboxylic acid anhydride.

The iodine value of these alkenyl group-containing polyether resin, acrylic resin, polyester resin, polycarbonate resin and epoxy resin is preferably 50 to 250, more preferably 70 to 200. If the iodine value is less than 50, the crosslinked density of the cured coating film is low and sufficient mechanical strength cannot be obtained. On the other hand, when it exceeds 250, the flexibility of the coating film decreases. The number average molecular weight is preferably 300 to 20,000, more preferably 400 to 10,000.
When the number average molecular weight is less than 300, mechanical strength is low, while 2
If it exceeds 000, workability in forming a coating film decreases.

Among these alkenyl group-containing compounds, alkenyl group-containing polyether resin, alkenyl group-containing polycarbonate resin and alkenyl group-containing acrylic resin are particularly preferable.

(Iv) Blending Ratio of Hydrosilyl Group-Containing Compound and Alkenyl Group-Containing Compound The blending ratio of the hydrosilyl group-containing compound and the alkenyl group-containing compound is such that the hydrosilyl group-containing compound is one alkenyl group in the alkenyl group-containing compound. It is preferable that the number of hydrogen atoms bonded to the silicon atom is 0.3 to 4. If the hydrogen atom bonded to the silicon atom is out of this range, the remaining alkenyl group or hydrogen atom reacts with water or contaminants, the coating film is deteriorated by ultraviolet rays, or the storage stability of the coating is reduced. May occur. By adjusting the blending ratio of the hydrosilyl group-containing compound and the alkenyl group-containing compound in this manner, a cured coating film excellent in weather resistance, glossiness and flexibility can be obtained.

(2) Self-Crosslinkable Resin A compound having a plurality of hydrosilyl groups and a plurality of alkenyl groups in one molecule can be self-crosslinked by an intramolecular hydrosilylation reaction, and can be called a self-crosslinking resin. . The self-crosslinking resin can be produced by copolymerizing the above-mentioned hydrogen polysiloxane macromonomer, an alkenyl group-containing acrylic monomer and, if necessary, another ethylenically unsaturated monomer.

(I) Alkenyl Group-Containing Acrylic Monomer The alkenyl group-containing acryl-based monomer includes (1) (i
The alkenyl group-containing acrylic monomer described in ii) can be used, but in addition to formula (16):

Embedded image (However, p is an integer of 1 to 10.) Silicone monomers such as terminal vinyl polydimethylsiloxypropyl (meth) acrylate represented by the formula (1) can also be used.

(Ii) Ethylenically unsaturated monomer As an ethylenically unsaturated monomer used as necessary,
(1) (i) In addition to the ethylenically unsaturated monomer described in the hydrosilyl group-containing compound, a compound of formula (20):

Embedded image (However, R ⁶ is a hydrogen atom or a methyl group, and q is 0 to
It is an integer of 10. ) A fluorine-based (meth) acrylic monomer represented by the formula (1) can also be used.

(Iii) Addition amount of each monomer Regarding the addition amount of each monomer in the self-crosslinking resin, the addition amount of the hydrogen polysiloxane macromonomer is 1 to
99 parts by weight is preferable, and 40 to 60 parts by weight is more preferable. The addition amount of the alkenyl group-containing acrylic monomer is preferably 1 to 99 parts by weight, more preferably 40 to 60 parts by weight. The addition amount of the ethylenically unsaturated monomer is preferably 0 to 80 parts by weight,
20 to 40 parts by weight is more preferable. The number average molecular weight of these self-crosslinking resins is preferably 500 to 100,000,
0 to 20,000 is more preferable.

(Iv) Manufacturing Method The self-crosslinking resin can be manufactured by carrying out ordinary radical polymerization in a solution. When using an alkenyl ester of (meth) acrylic acid having a double bond at the terminal such as allyl (meth) acrylate or 3-butenyl methacrylate, copolymerize by anionic polymerization or radical polymerization using a chain transfer agent. You can also Further, instead of using an alkenyl group-containing acrylic monomer, acrylic acid or methacrylic acid is copolymerized with other monomer components, and then the resulting acid group-containing copolymer is treated with an alkenyl group-containing alcohol such as allyl alcohol or 2-butenol. You may esterify. After further copolymerizing glycidyl methacrylate with another monomer component, acrylic acid or methacrylic acid may be subjected to a ring-opening addition reaction to the glycidyl group of the resulting copolymer, 2-isocyanatoethyl methacrylate, methacryloyl isocyanate, After copolymerizing an isocyanate group-containing monomer such as m-isopropenyl-α, α-dimethylbenzyl isocyanate with another monomer component, the above-mentioned alkenyl group-containing alcohol may be subjected to an addition reaction.

(3) Catalyst A catalyst is required for the hydrosilylation reaction to the carbon-carbon double bond in the blend of the hydrosilyl group-containing compound and the alkenyl group-containing compound used in the present invention and the self-crosslinking resin. As the hydrosilylation catalyst, a group VIII transition metal or a compound thereof, for example, a compound such as platinum, palladium, rhodium or ruthenium, particularly a complex can be used. Specifically, PtCl ₄ , H ₂ PtCl ₆ · 6H can be used.
₂ O, Pt-vinyl siloxane complex (for example, Pt
_r (ViMe ₂ SiOSiMe ₂ Vi) _s, etc.), Pt−
Phosphine complex (for example, Pt (PPh ₃ ) ₄ etc.), P
t-olefin complex (for example, PtCl ₂ (cod),
Pt (acac) ₂ , trans- or cis- [Pt
Cl ₂ (NH ₂ Pr) ₂ ], etc.), PdCl ₂ (PP
h ₃ ) ₂ , PdCl ₂ (PhCN) ₂ , RhCl ₂ (P
Ph ₃ ) ₃ , [RhCl (cod)] ₂ , Ru (cp
d) ₂ (wherein Me is a methyl group, Vi is a vinyl group, Ph is a phenyl group, Pr is a propyl group, cod is a cyclooctadiene, acac is acetylacetonate, cpd is cyclopentadiene, and r and s are integers.) and the like.

In addition, a ruthenium carbonyl metal cluster complex, a (cyclopentadienyl) tri- (aliphatic group) platinum complex described in Japanese Patent Publication No. 6-503591, and 6-
The (diolefin) (aryl) platinum complex described in No. 503592 can also be used. Of these, platinum catalysts are common. These catalysts can be used after diluting with a solvent such as alcohols, aromatic or aliphatic hydrocarbons, ketones, and basic solvents as needed.

The amount of these catalysts used is preferably 5 to 10,000 ppm, and particularly preferably 20 to 1,000 ppm, per 100 parts by weight of the resin solid content of the topcoat composition. If the amount of the catalyst used is less than 5 ppm, the curability is poor. Meanwhile 10,000p
If it exceeds pm, the cured coating film may be colored by the color of the catalyst, and in addition, since the Group VIII transition metal is expensive, the production cost is high.

For the purpose of controlling the reactivity, a substance (retarder) which coordinates curing with a catalyst such as an acetylene compound and delays curing may be appropriately added. Examples of such a slow-acting agent include ethynyl alcohol, propargyl alcohol, 2-methyl-3-butyn-2-ol, 3-trimethylsiloxypropyne, 3-trimethylsiloxy-3,3-dimethylpropyne, bis (1, 1-dimethyl-2-propynyloxy) dimethylsilane, bis (1,1-dimethyl-2-propynyloxy) diphenylsilane, bis (1,1-dimethyl-2-propynyloxy) phenylmethylsilane, α, α-dialkyl It is possible to use a polymer obtained by polymerizing an ester of (meth) acrylic acid with propargyl alcohol or the like or an ethylene oxide adduct thereof. Further, an alkynyl group-containing acrylic polymer described in JP-A-5-287206 may be used.

(4) Other Components In principle, the top coat composition does not contain a pigment, but it may be added as long as the transparency is not impaired.
In addition, for example, viscosity modifiers such as organic montmorillonite, polyamide and polyethylene wax, surface modifiers such as silicone and organic polymers, UV absorbers, antioxidants such as hindered phenols and hindered amines, and light stabilizers and other conventional agents. Additives can be added.

(5) Physical Properties The viscosity of such a topcoat composition is 30 to 1,000 centipoise (20 ° C.), and the dynamic glass transition temperature Tg of the cured coating film is 140 ° C. or higher. In thermogravimetric measurement, the residual weight at 500 ° C is 20% by weight or more. 80 more
It has a water contact angle of more than °.

The coating film obtained from such a topcoat composition exhibits excellent protection properties required for the topcoat, such as weather resistance, solvent resistance, chemical resistance, impact resistance and scratch resistance. Also, it has excellent finish appearance such as transparency and gloss. Furthermore, since it has high water repellency comparable to that of a known water-repellent top coat containing a fluororesin, stains are unlikely to adhere, and even if adhered, it can be easily washed and removed. Further, since the top coat composition used in the present invention can be prepared in an ultra-high solid type having a nonvolatile content of 60% by weight or more, the release of the organic solvent into the atmosphere can be greatly reduced.

(6) Overcoat composition The above-mentioned topcoat composition can also be used as an overcoat composition, and likewise has weather resistance, solvent resistance, chemical resistance, impact resistance, scratch resistance, and transparency. A cured coating film having excellent properties, glossiness and water repellency can be obtained. Therefore, the description of the coating composition herein applies as it is to the overcoat composition.

[3] Method for forming multi-layer coating film Base coat and top coat (or overcoat)
The coating method for forming the multi-layer coating film may be the same as the conventional method. For example, in the case of an automobile body, a steel sheet subjected to chemical conversion treatment is electrodeposited with an electrodeposition coating, and if necessary, an intermediate coating is applied on the steel sheet as a coating object. It is preferable to apply the base coat composition to the article to be coated, set it, and then apply the top coat composition by a wet-on-wet system. It is also possible to apply a preferably transparent overcoat after applying the topcoat composition. The base coat and the top coat (and the overcoat) may be baked at the same time or sequentially. That is, the multilayer coating film can be formed by a 3 coat 1 bake, a 2 coat 1 bake, a 3 coat 3 bake, a 2 coat 2 bake system or the like. When a water-based paint is used as the base coat to form a coating film by the two-coat one-bake method, it is preferable to preheat at 100 ° C or lower (for example, about 80 ° C) for about 10 minutes instead of setting after coating the basecoat. .

The coating method is not particularly limited, but air spray coating, electrostatic coating and the like are preferable. The dry film thickness of the base coat is preferably 10 to 30 μm, the dry film thickness of the top coat is preferably 20 to 50 μm, and the dry film thickness of the overcoat is preferably 20 to 50 μm. Baking temperature is 120-16
The temperature is preferably 0 ° C., and the baking time is preferably 20 to 40 minutes.

When the coating film is formed by the two-coat, two-bake method, a high energy ray curable type such as ultraviolet ray or a room temperature curable type coating material can be used as the top coat composition. Even in that case, modification such as addition of a photosensitizer to the composition or omission of addition of a retarder which suppresses a coordination early reaction to the catalyst is required.

[0095]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. Production Example 1 Synthesis of alkenyl group-containing acrylic resin (A-1) 150 parts by weight of xylene was charged into a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen gas introducing pipe and a dropping funnel, and nitrogen gas was introduced. While the temperature was raised to 130 ° C., the following mixed solution was added dropwise from the dropping funnel at a constant rate over 3 hours.

3-Methyl-3-butenyl methacrylate 50 parts by weight Cyclohexenyl methyl methacrylate 40 parts by weight 2,4-diphenyl-4-methyl-1-pentene 10 parts by weight 2,2′-azobis (methyl isobutrate) 10 parts by weight

After completion of the dropping, the mixture was aged at 130 ° C. for 1 hour, and then 10 parts by weight of xylene and 0.5 parts by weight of 2,2′-azobis (methyl isobutate) were added dropwise over 30 minutes, and aged at 130 ° C. for 2 hours. After that, it was cooled to 50 ° C. Then, the solvent was removed at 50 ° C. and 10 mmHg to obtain an alkenyl group-containing acrylic resin (A-1) having a number average molecular weight of 1460 and a nonvolatile content of 95.2%.

Production Example 2 Production of Waterborne Urethane Base Coating (B-4) 150 parts by weight of 2-hydroxyethyl methacrylate and n-
350 parts by weight of butyl acrylate, 300 parts by weight of methyl methacrylate, 200 parts by weight of glycidyl methacrylate, 17 parts by weight of azobisisobutyronitrile, 33 parts by weight of t-dodecyl mercaptan, and 670 parts by weight of ethylene glycol monoethyl ether acetate. And were reacted to obtain an acrylic resin solution (A-2).

122 parts by weight of 2,4-tolylene diisocyanate, diethylene glycol monoethyl ether acetate 312
By weight, 45 parts by weight of ethylene glycol monoethyl ether were reacted to obtain a partially blocked isocyanate. Next, 724 parts by weight of the acrylic resin solution (A-2) was added, and the reaction was continued at 70 to 75 ° C. for 5 hours, and it was confirmed by IR spectrum that the isocyanate group had disappeared. Further, 88 parts by weight of dipropylamine was added dropwise to the reaction solution, and the mixture was stirred. To this solution, 64 parts by weight of propionic acid, 4,74 parts of deionized water
7 parts by weight, ethylene glycol monoethyl ether 1,43
2 parts by weight was added to obtain a resin solution (A-3) solubilized with an ammonium salt.

1,000 parts by weight of the obtained resin solution (A-3), 800 parts by weight of an acrylic resin solution (A-2), 100 parts by weight of titanium dioxide, 2 parts by weight of Emulgen 910, and 700 parts of deionized water. Parts by weight and 300 parts by weight of isopropanol were mixed to obtain an aqueous urethane base coating material (B-4).

Production Example 3 Production of Acrylic Modified Epoxy Resin (A-4 ) 800 parts by weight of Epicoat 1009 ( manufactured by Shell Chemical Co., epoxy equivalent 2800) and 1000 parts by weight of butyl cellosolve were placed in a flask and completely dissolved at 115 ° C. , Methacrylic acid 120
A mixture of 1 part by weight, 80 parts by weight of styrene and 47 parts by weight of benzoyl peroxide was added dropwise over 2 hours. After the dropping was completed, the mixture was stirred at 115 ° C for 2 hours, and 142 parts by weight of butyl cellosolve was added.
After cooling to 80 ° C., a mixture of 100 parts by weight of dimethylaminoethanol and 324 parts by weight of ion-exchanged water was added dropwise over 1 hour to obtain an acrylic modified epoxy resin (A-4).

Example 1 A cationic electrocoating (Power Top PU-50, Nippon Paint Co., Ltd.) was applied to a 0.8 mm thick dull steel plate treated with zinc phosphate.
16) by electrodeposition coating so that the dry film thickness will be about 25 μm.
Baking for 30 minutes at 0 ° C. After that, an intermediate coating (Olga P-2 Schiller, manufactured by Nippon Paint Co., Ltd.) was dried to a film thickness of about 40.
It was coated to a thickness of μm and baked at 140 ° C. for 30 minutes.

The following aqueous metallic base paints (B-
Adjust the viscosity of 1) with Ford Cup # 4 for 30 seconds, and apply a two-stage coating with air spray to a dry film thickness of about 15 μm.
After preheating at ℃ for 10 minutes, the following top coat (T
-1, non-volatile content 97.8%, viscosity (20 ℃) 68 centipoise,
Wet hydrosilyl group / alkenyl group = 1/1)
Painted on-wet. Then, it was baked at 140 ° C. for 30 minutes to obtain a test piece having a dry film thickness of 40 μm.

Ingredients of water-based metallic base paint (B-1) Solid content Weight part Aluminum flake paste ⁽¹⁾ 10 Methyl etherified melamine resin ⁽²⁾ 30 Isostearyl phosphate 1 Water-based acrylic resin varnish ⁽³⁾ 56 Note (1 ⁾ ) Aluminum flake content = 65% by weight. (2) Nonvolatile content = 100% by weight, content of imino group per triazine ring = 0.1. (3) Nonvolatile content = 50% by weight, solid content obtained by polymerizing the following monomers 50% by weight, number average molecular weight 12,000, hydroxyl value 70
And an acrylamide-containing acrylic resin having an acid value of 58. Ethylene glycol monobutyl ether 76 parts by weight, styrene 15
Parts by weight, 63 parts by weight of methyl methacrylate, 2-methacrylic acid
Hydroxyethyl 48 parts by weight, n-butyl acrylate 117
Parts by weight, 27 parts by weight of methacrylic acid, 30 parts by weight of acrylamide, 3 parts by weight of azobisisobutyronitrile, 28 parts by weight of dimethylethanolamine, and 200 parts by weight of deionized water.

Ingredients by Weight of Top Coat (T-1) Part by Weight (Based on Solid Content ) Alkenyl Group-Containing Compound ⁽¹⁾ 50 Hydrosilyl Group-Containing Compound A ⁽²⁾ 50 H ₂ PtCl ₆ .6H ₂ O ⁽³⁾ 1 Benzophenone Light stabilizers 5 Hindered phenolic antioxidants 2 3-Methyl-1-butyn-1-ol 1 Note (1) Nonvolatile content = 100% by weight, structural formula (9):

Embedded image (2) Nonvolatile content = 94% by weight, structural formula (18):

Embedded image (3) 2% isopropyl alcohol (IPA) solution.

The test pieces thus obtained were evaluated for pencil hardness, coating appearance, scratch resistance and acid resistance by the following methods. Table 1 shows the results.

(1) Pencil hardness: The pencil hardness was measured according to JIS K5400. ○ ... B or more. Δ: 2B. X: 3B or less.

(2) Appearance of coating film: The appearance of the coating film was visually evaluated. ○: No abnormality. X: "Waviness" (round feeling) was recognized in the coating film.

(3) Scratch resistance: A 2 cm × 2 cm flannel cloth impregnated with 1 g of a 50% water dispersion of cleanser (New Homing Cleanser, manufactured by Kao Corporation) was applied to a Gakushin-type dyeing friction fastness tester ( It was attached to a vibrating head of Daiei Kagaku Seiki Co., Ltd., and was reciprocated 10 times while contacting the test piece with a load of 500 g. Then, 20 ° gloss of the test portion was measured, the gloss retention was calculated, and evaluated according to the following criteria. ○: Gross retention was 85% or more. B: Gloss retention was 70% or more and less than 85%. X: The gloss retention was less than 70%.

(4) Acid resistance: After contact with 0.2 ml of 40% sulfuric acid aqueous solution at 60 ° C. for 15 minutes, the surface of the coating film was visually judged. ◎ ... No abnormality. ○: There are slight traces. △: The trace was large. X: An abnormality was recognized.

Example 2 The following topcoat (T-2, non-volatile content 102.7%, viscosity (20 ° C.) 565 centipoise, hydrosilyl group / alkenyl group = 3/2) was used instead of the topcoat (T-1). A test piece was prepared and evaluated in the same manner as in Example 1 except that it was used.

Component by Weight of Topcoat (T-2) (Based on Solid Content ) Alkenyl Group-Containing Acrylic Resin of Production Example 1 58 Hydrosilyl Group-Containing Compound A (Nonvolatile Content 94%) 43 H ₂ PtCl ₆ .6H ₂ O (2% IPA solution) 1.5 Hindered phenolic antioxidant 1 3-Methyl-1-butyn-1-ol 1 Ethyl acetate aluminum diisopropylate 5

Example 3 Test pieces were prepared and evaluated in the same manner as in Example 1 except that the following aqueous solid base paint (B-2) was used instead of the aqueous metallic base paint (B-1).

Ingredients of Water-based Solid Base Coating (B-2) Part by Weight (Based on Solid Content ) Carbon Black 4 Butyletherified Melamine Resin ⁽¹⁾ 30 Water-based Acrylic Resin Varnish ⁽²⁾ 56 Note (1) Nonvolatile Content = 60 parts by weight %. (2) Nonvolatile content = 50% by weight, content of imino group per triazine ring = 0.7.

Example 4 Instead of the top coat (T-1), the top coat used in Example 2 (T-2, non-volatile content 102.7%, viscosity (20 ° C.))
565 centipoise, hydrosilyl group / alkenyl group = 3
/ 2) was used and a test piece was prepared and evaluated in the same manner as in Example 3.

Example 5 An object to be coated was prepared in the same manner as in Example 1, and the following solvent-type metallic base paint (B-3) was applied by air spraying to a dry film thickness of about 15 μm for about 7 minutes. After setting, a top coat (T-1, nonvolatile content 97.8% by weight, viscosity (20 ° C.) 68 centipoise, hydrosilyl group / alkenyl group = 1/1) was applied by a wet-on-wet method. Then, bake at 140 ℃ for 30 minutes, dry film thickness 40μ
A test piece of m was prepared and evaluated in the same manner as in Example 1.

Ingredients by Weight of Solvent-Type Metallic Base Coating (B-3) (Based on Solid Content ) Aluminum Flake Paste ⁽¹⁾ 11 Butyletherified Melamine Resin ⁽²⁾ 6 Thermosetting Acrylic Resin Varnish ⁽³⁾ 38 Toluene 6 n-Butanol 2 Triethylamine 1 Note (1) Aluminum flake content = 65% by weight. (2) Nonvolatile content = 60% by weight, content of imino group per triazine ring = 0.7. (3) Nonvolatile content = 48% by weight, ALMATEC NT-U-448
(Mitsui Toatsu Chemical Co., Ltd.).

Example 6 Instead of the top coat (T-1), the top coat used in Example 2 (T-2, non-volatile content 102.7%, viscosity (20 ° C.))
565 centipoise, hydrosilyl group / alkenyl group = 3
/ 2) was used and a test piece was prepared and evaluated in the same manner as in Example 5.

Example 7 A test piece was prepared and evaluated in the same manner as in Example 1 except that the water-based urethane base paint (B-4) of Production Example 2 was used in place of the water-based metallic base paint (B-1). .

Example 8 The top coat (T-2, nonvolatile content 102.7%, viscosity (20 ° C.)) used in Example 2 instead of the top coat (T-1).
565 centipoise, hydrosilyl group / alkenyl group = 3
/ 2) was used and a test piece was prepared and evaluated in the same manner as in Example 7.

Example 9 A test piece was prepared and evaluated in the same manner as in Example 1 except that the following aqueous epoxy base coating material (B-5) was used instead of the aqueous metallic base coating material (B-1).

Component by Weight of Aqueous Epoxy-Based Paint (B-5) (Based on Solid Content) Epoxy Resin (A-4) 54 in Production Example 3 54 Diaminodiphenylmethane 6 Titanium Dioxide 12

Example 10 The top coat (T-2, nonvolatile content 102.7%, viscosity (20 ° C.)) used in Example 2 instead of the top coat (T-1).
565 centipoise, hydrosilyl group / alkenyl group = 3
/ 2) was used, and a test piece was prepared and evaluated in the same manner as in Example 9.

Example 11 Example 1 was repeated except that an aqueous acrylic emulsion base coating (B-6, trade name "Audelac", manufactured by Nippon Paint Co., Ltd.) was used in place of the aqueous metallic base coating (B-1). Test pieces were prepared and evaluated in the same manner as in.

Example 12 Instead of the top coat (T-1), the top coat used in Example 2 (T-2, nonvolatile content 102.7%, viscosity (20 ° C.))
565 centipoise, hydrosilyl group / alkenyl group = 3
/ 2) was used and a test piece was prepared and evaluated in the same manner as in Example 11.

Comparative Example 1 A test piece was prepared and evaluated in the same manner as in Example 1 except that the following aqueous metallic base coating (B-7) was used in place of the aqueous metallic base coating (B-1).

Ingredients by weight of water-based metallic base paint (B-7) (based on solid content) Aluminum flake paste ⁽¹⁾ 10 Methyl etherified melamine resin ⁽²⁾ 30 Water-based acrylic resin varnish ⁽³⁾ 56 Note (1) Aluminum flake content = 65% by weight. (2) Nonvolatile content = 80% by weight, content of imino group per triazine ring = 1.7. (3) Nonvolatile content = 50% by weight.

Comparative Example 2 The top coat (T-2, nonvolatile content 102.7%, viscosity (20 ° C.) used in Example 2 instead of the top coat (T-1) was used.
565 centipoise, hydrosilyl group / alkenyl group = 3
A test piece was prepared and evaluated in the same manner as in Comparative Example 1 except that / 2) was used.

Comparative Example 3 A test piece was prepared and evaluated in the same manner as in Example 5 except that the following solvent type metallic base paint (B-8) was used in place of the solvent type metallic base paint (B-3). .

Ingredients in Solvent Type Metallic Base Coating (B-8) Part by Weight (Based on Solid Content) Carbon Black 2 Butyletherified Melamine Resin ⁽¹⁾ 21 Polyester Resin ⁽²⁾ 27 Alkyd Resin ⁽³⁾ 38 Solvesso 100 8 n -Butanol 3 Triethylamine 0.5 Note (1) Nonvolatile matter = 50% by weight, content of imino group per triazine ring = 1.6. (2) Acid value = 5, OH value = 80, number average molecular weight = 3380. (3) Acid value = 8, OH value = 110, number average molecular weight = 2700, oil length = 20.

Comparative Example 4 Instead of the top coat (T-1), the top coat used in Example 2 (T-2, non-volatile content 102.7%, viscosity (20 ° C.))
565 centipoise, hydrosilyl group / alkenyl group = 3
A test piece was prepared and evaluated in the same manner as in Comparative Example 3 except that / 2) was used.

Table 1 Types of paints Characteristics of coating film No. Base Top Pencil Hardness Coating Appearance Acid Resistance Scratch Resistance Example 1 B-1 T-1 ○ ○ ◎ ○ Example 2 B-1 T-2 ○ ○ ◎ ○ Example 3 B-2 T-1 ○ ○ ○ ○ Example 4 B-2 T-2 ○ ○ ○ ○ Example 5 B-3 T-1 ○ ○ ○ ○ Example 6 B-3 T-2 ○ ○ ○ ○ Example 7 B-4 T-1 ○ ○ ○ ○ Example 8 B-4 T-2 ○ ○ ○ ○ Example 9 B-5 T-1 ○ ○ ○ ○ Example 10 B-5 T-2 ○ ○ ○ ○ Example 11 B-6 T- 1 ○ ○ ○ ○ Example 12 B-6 T-2 ○ ○ ○ ○ Comparative Example 1 B-7 T-1 × × × × Comparative Example 2 B-7 T-2 × × × × Comparative Example 3 B-8 T-1 × × × × Comparative Example 4 B-8 T-2 × × × ×

As is clear from Table 1, the multilayer coating films of Examples 1 to 12 are excellent in coating hardness, coating appearance, scratch resistance and acid resistance. On the other hand, the multilayer coating films of Comparative Examples 1 to 4 are inferior in coating film hardness, coating film appearance, scratch resistance and acid resistance.

The following are mentioned as preferred embodiments of the present invention. (1) A method for forming a multilayer coating film, wherein the crosslinking agent in the base coat composition is a melamine resin. (2) A method for forming a multilayer coating film, wherein the crosslinking agent in the base coat composition is a melamine resin having 0 to 0.2 imino groups per triazine ring. (3) A method for forming a multilayer coating film, wherein the functional resin in the base coat composition is at least one of an organic solvent type or water-based acrylic resin, polyester resin and epoxy resin. (4) A method for forming a multilayer coating film, wherein the crosslinking agent in the base coat composition is a (block) isocyanate compound or amine compound. (5) A method for forming a multilayer coating film, wherein the hydrosilylation catalyst is a compound of platinum, palladium, rhodium or ruthenium. (6) A method for forming a multilayer coating film, wherein the concentration ratio of hydrosilyl group / alkenyl group in the topcoat composition is 0.3 to 4. (7) A method for forming a multilayer coating film, wherein the nonvolatile content in the top coat composition is 60% by weight or more. (8) A method for forming a multilayer coating film, which comprises pre-heating an aqueous base coat film coated on an object to be coated, coating the top coat composition, and simultaneously curing both. (9) A method for forming a multilayer coating film, which comprises coating the topcoat composition by wet-on-wet on an aqueous basecoat coating film applied to an object to be coated, and curing both at the same time. (10) The topcoat composition is applied wet-on-wet on the water-based basecoat coating film applied to the object to be coated, both are simultaneously cured, and then a transparent overcoat composition is applied and cured. A method for forming a multilayer coating film, which is characterized by the above.

[0135]

In the method of the present invention, the base coat composition contains a cross-linking agent which does not inhibit the hydrosilylation reaction of the top coat composition and a functional resin which can react with the cross-linking agent. A multilayer coating film having excellent coating film hardness, coating film appearance, scratch resistance and acid resistance can be obtained.
Such a method for forming a multilayer coating film is suitable for coating the outer panel of a vehicle body of an automobile.

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[Procedure amendment]

[Submission date] June 18, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

(Iii) Curing agent for epoxy resin As a curing agent for epoxy resin, a chain aliphatic polyamine such as diethylenetriamine, triethylenetetraamine, ethylaminopropylamine, a cycloaliphatic polyamine, an aliphatic polyamine adduct, ketimine, Modified aliphatic polyamine, polyamidoamine, aromatic amine, aromatic modified amine, aromatic polyamine such as diaminodiphenylmethane, aromatic modified polyamine, tertiary amine curing agent, mercaptan curing agent, acid anhydride curing agent, Copolymers having acid anhydride groups such as ethylene-maleic anhydride copolymers, compounds having phenolic hydroxyl groups such as phenol resin initial condensation products, dicyandiamide, silicon trifluoride-
Examples thereof include silicon trifluoride-based composites such as amine complex compounds. Among these curing agents, dicyandiamide, diaminodiphenylmethane, and silicon trifluoride-amine complex compound are preferable.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

Further, copolymerizable (meth) acrylonitrile, styrene, (meth) acrylic acid amide, dimethyl acrylamide, N, N-dimethylpropyl acrylamide, N-butoxymethyl acrylamide, diacetone acrylamide, etc. with the above-mentioned monomers. Can be blended.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction contents]

When the hydroxyl group-containing acrylic resin is made aqueous, it is partially or completely neutralized with a volatile base. Ammonia or amine is preferred as the volatile base. Particularly preferred amines are monopropylamine, monobutylamine, diethylamine, dibutylamine, triethylamine, tributylamine, monoethanolamine, ethylmonoethanolamine, dimethylaminoethanol, 2-amino-2-methyl-1-propanol,
Examples thereof include primary amines such as cyclohexylamine, morpholine and piperidine, secondary amines and tertiary amines.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0024

[Correction method] Change

[Correction contents]

Examples of the polybasic acid or its anhydride include phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, tetrahydrophthalic anhydride and hexahydrophthalic anhydride. Acid, maleic anhydride, fumaric acid, itaconic acid, trimellitic anhydride, etc. are mentioned, and these can be used in combination of 2 or more types.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

[Correction contents]

(5) Other Additives In the base coat composition, if necessary, an acid catalyst, a benzophenone-based UV absorber, a phenol-based and sulfide-based antioxidant, and a surface modifier such as silicone or organic polymer. , Anti-sagging agent, thickening agent and the like can be added in an amount of about 0.1 to 5% by weight.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0037

[Correction method] Change

[Correction contents]

(1) Blend of Hydrosilyl Group-Containing Compound and Alkenyl Group-Containing Compound (i) First Hydrosilyl Group-Containing Compound The first hydrosilyl group-containing compound has the general formula:

Embedded image (wherein R ¹ is an alkyl group having 1 to 6 carbon atoms, a phenyl group or a phenethyl group, R ² is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group or a phenethyl group, a is a number of 2 to 200) and is an organohydrogenpolysiloxane having at least two hydrosilyl groups in one molecule.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0043

[Correction method] Change

[Correction contents]

(Ii) Second Hydrosilyl Group-Containing Compound The second hydrosilyl group-containing compound has the general formula:

Embedded image (wherein R ¹ is an alkyl group having 1 to 6 carbon atoms, a phenyl group or a phenethyl group, and R ² is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group or a phenethyl group, b is a number of 1 to 30), has at least one hydrosilyl group in one molecule, and has at least one (meth) acryloyloxy group in the middle or at the end of the siloxane skeleton. It is a homopolymer or copolymer of a hydrogen polysiloxane macromonomer having an alkylene group (however, the alkenyl group is not included). The (meth) acryloyloxyalkylene group is preferably a 3- (meth) acryloyloxypropylene group or the like. Homopolymerization or copolymerization of the hydrogen polysiloxane macromonomer can be carried out by a known solution polymerization method. The details of the homopolymers or copolymers of the hydrogen polysiloxane macromonomers (however, the alkenyl groups are not included) are described in JP-A Nos. 7-11114 and 4-169589. The term "(meth) acryloyl" used in the present specification means acryloyl or methacryloyl.

[Procedure amendment 8]

[Document name to be amended] Statement

[Name of item to be corrected] 0045

[Correction method] Change

[Correction contents]

[0045]

(Wherein R ³ is an alkyl group having 1 to 6 carbon atoms, a phenyl group or a phenethyl group, A is a (meth) acryloyloxyalkylene group, j is a number of 0 to 20, and k is Is a number from 1 to 3 and 1 is a number from 0 to 10.). However, the arrangement of each structural unit and terminal group is arbitrary.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Change

[Correction contents]

[0046]

Embedded image (wherein R ³ is an alkyl group having 1 to 6 carbon atoms,
It is a phenyl group or a phenethyl group, A is a (meth) acryloyloxyalkylene group, j is a number from 0 to 20, k is a number from 1 to 3, and m is a number from 1 to 10. ). However, the arrangement of each structural unit and terminal group is arbitrary.

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0047

[Correction method] Change

[Correction contents]

[0047]

Embedded image (wherein A is a (meth) acryloyloxyalkylene group, and R ³ and R ⁴ are an alkyl group having 1 to 6 carbon atoms, a phenyl group, a phenethyl group, or —OSi.
(R ³ ) ₂ H, and R ⁵ is a hydrogen atom or —OSi (R
³ ) ₂ H, and n is a number from 1 to 10. ).

[Procedure amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0048

[Correction method] Change

[Correction contents]

When the (meth) acryloyl group-containing hydrogen polysiloxane macromonomer is used as a copolymer, an ethylenically unsaturated monomer (not including an alkenyl group) is used as a monomer for copolymerization (however, it does not contain an alkenyl group). For example, it is preferable to use acrylic monomers, vinyl monomers, etc.). Examples of acrylic monomers include (meth) acrylic acid esters (eg, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate,
2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (Meth) acrylic acid 4-hydroxybutyl),
2-Hydroxyethyl (meth) acrylate and poly-ε-
Addition product with caprolactone, epoxy group-containing (meth) acrylic acid ester (eg, glycidyl (meth) acrylate), 3-trimethoxysilylpropyl (meth) acrylate, 3-triethoxysilylpropyl (meth) acrylate, (Meth) acrylic acid 3-dimethoxymethylsilylpropyl), (meth) acrylic acid-2-acrylamido-2-methylpropanesulfonic acid, acid phosphoxypropyl methacrylate, (meth) acrylic acid tributyltin, (meth) acrylamide, ( Examples thereof include (meth) acryloyl cyanate, and (meth) acrylic acid-2-isocyanatoethyl. Examples of vinyl monomers include styrene, α-methylstyrene, itaconic acid, maleic acid, vinyl acetate, allyl acetate, vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, and N. -Cyclohexylmaleimide, N-phenylmaleimide and the like can be mentioned. Further, silicone macromonomer can also be used.

[Procedure amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0062

[Correction method] Change

[Correction contents]

Other acrylic monomers that can be copolymerized with the alkenyl group-containing acrylic monomer include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylic acid 2
-Ethylhexyl, lauryl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (meth) acrylic acid 4 -Hydroxybutyl, (meth) acrylic acid 2-
Addition product of hydroxyethyl and poly-ε-caprolactone, glycidyl (meth) acrylate, 3-trimethoxysilylpropyl (meth) acrylate, 3-triethoxysilylpropyl (meth) acrylate, and (meth) acrylic acid 3 -Dimethoxymethylsilylpropyl, (meth) acrylic acid 2-acrylamido-2-methylpropanesulfonic acid, acid phosphoxypropyl methacrylate,
(Meth) tributyltin acrylate, (meth) acrylamide, (meth) acryloyl isocyanate, (meth)
2-isocyanatoethyl acrylate and the like can be mentioned.
Further, within a range of 50% by weight or less, an ethylenically unsaturated monomer other than the acrylic monomer (for example, styrene, α
-Methylstyrene, 2,4-diphenyl-4-methyl-
1-pentene, itaconic acid, maleic acid, vinyl acetate,
Allyl acetate, vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, N-cyclohexylmaleimide, N-phenylmaleimide, etc.) can also be copolymerized. Further, a silicone macromonomer can be copolymerized.

[Procedure amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0063

[Correction method] Change

[Correction contents]

As the method for synthesizing the alkenyl group-containing acrylic resin, an addition reaction of a hydroxyl group-containing acrylic resin with an alkenyl isocyanate and / or an alkenyl group-containing carboxylic acid anhydride, an addition reaction of an isocyanate group-containing acrylic resin with an alkenyl alcohol Examples thereof include a reaction, an addition reaction between a carboxyl group-containing acrylic resin and an alkenyl group-containing epoxy, and an addition reaction between an epoxy group-containing acrylic resin and an alkenyl group-containing carboxylic acid.

[Procedure Amendment 14]

[Document name to be amended] Statement

[Correction target item name] 0079

[Correction method] Change

[Correction contents]

(2) Self-Crosslinkable Resin A compound having a plurality of hydrosilyl groups and a plurality of alkenyl groups in one molecule can be self-crosslinked by an intramolecular hydrosilylation reaction, and can be called a self-crosslinking resin. . The self-crosslinking resin can be produced by copolymerizing the above-mentioned hydrogen polysiloxane macromonomer, an alkenyl group-containing acrylic monomer and, if necessary, another ethylenically unsaturated monomer.

[Procedure Amendment 15]

[Document name to be amended] Statement

[Correction target item name] 008

[Correction method] Change

[Correction contents]

The amount of these catalysts used is preferably 5 to 10,000 ppm, more preferably 20 to 1,000 ppm, based on the resin solid content of the topcoat composition. If the amount of the catalyst used is less than 5 ppm, the curability is poor. Meanwhile 10,
If it exceeds 000 ppm, the cured coating film may be colored by the color of the catalyst, and in addition, since the Group VIII transition metal is expensive, the production cost is high.

[Procedure Amendment 16]

[Document name to be amended] Statement

[Correction target item name] 0089

[Correction method] Change

[Correction contents]

(5) Physical Properties The viscosity of such a top coat composition is 30 to 1.0.
It is 00 centipoise (20 ° C), and the dynamic glass transition temperature Tg of the cured coating film is 40 ° C or higher. In thermogravimetric measurement, the residual weight at 500 ° C. is 20% by weight or more. Further, it has a water contact angle of 80 ° or more.

[Procedure amendment 17]

[Document name to be amended] Statement

[Correction target item name] 0096

[Correction method] Change

[Correction contents]

3-Methyl-3-butenyl methacrylate 50 parts by weight Cyclohexenyl methyl methacrylate 40 parts by weight 2,4-diphenyl-4-methyl-1-pentene 10 parts by weight 2,2′-azobis (methylisobutyrate) 10 parts by weight

[Procedure amendment 18]

[Document name to be amended] Statement

[Correction target item name] 0097

[Correction method] Change

[Correction contents]

After completion of dropping, the mixture was aged at 130 ° C. for 1 hour,
10 parts by weight of xylene and 0.5 parts by weight of 2,2′-azobis (methylisobutyrate) were added dropwise over 30 minutes to give 13
After aging at 0 ° C for 2 hours, it was cooled to 50 ° C. Then 5
The solvent is removed at 0 ° C and 10 mmHg, and the number average molecular weight is 1
An alkenyl group-containing acrylic resin (A-1) having a solid content of 460 and a non-volatile content of 95.2% was obtained.

[Procedure amendment 19]

[Document name to be amended] Statement

[Correction target item name] 0102

[Correction method] Change

[Correction contents]

Example 1 A 0.8 mm thick dull steel sheet treated with zinc phosphate was coated with a cationic electrodeposition coating (Power Top U-50, manufactured by Nippon Paint Co., Ltd.) so that the dry film thickness was about 25 μm. The coating was applied and baked at 160 ° C. for 30 minutes. After that, an intermediate coating (Olga P-2 Schiller, manufactured by Nippon Paint Co., Ltd.) was applied to a dry film thickness of about 40 μm, and the coating was applied at 140 ° C. for 3 days.
Bake for 0 minutes.

[Procedure amendment 20]

[Document name to be amended] Statement

[Correction target item name] 0117

[Correction method] Change

[Correction contents]

[0117]

[Procedure amendment 21]

[Document name to be amended] Statement

[Correction target item name] 0129

[Correction method] Change

[Correction contents]

Comparative Example 3 Example 5 except that the following solvent type base paint (B-8) was used in place of the solvent type metallic base paint (B-3).
Test pieces were prepared and evaluated in the same manner as in.

[Procedure amendment 22]

[Document name to be amended] Statement

[Correction target item name] 0130

[Correction method] Change

[Correction contents]

[0130]

Claims (8)

[Claims] 1. A method for forming a multilayer coating film by coating a base coat composition on an object to be coated, coating a top coat composition thereon, and curing the both separately or simultaneously, wherein the top coat comprises: The composition comprises (a) a blend of a compound having a plurality of hydrosilyl groups and a compound having a plurality of alkenyl groups, or a compound having both a plurality of hydrosilyl groups and a plurality of alkenyl groups, and (b) a catalytic amount of hydrosilylation. Containing a catalyst, the base coat composition, (c) a cross-linking agent that does not inhibit the hydrosilylation reaction of the top coat composition, and (d) a functional resin capable of reacting with the cross-linking agent. A method for forming a multi-layer coating film characterized. 2. The method for forming a multilayer coating film according to claim 1, wherein the crosslinking agent (c) is 0 to 1 per triazine ring.
A method for forming a multilayer coating film, which is an amino resin having one imino group. 3. The method for forming a multilayer coating film according to claim 1 or 2, wherein one alkenyl group in the alkenyl group-containing compound is hydrogen bonded to a silicon atom in the hydrosilyl group-containing compound. A method for forming a multilayer coating film, wherein the number of atoms is 0.3 to 4. 4. The method for forming a multilayer coating film according to claim 1, wherein the compound having a plurality of hydrosilyl groups is (1) a compound represented by the general formula: (However, R ¹ is an alkyl group having 1 to 6 carbon atoms, a phenyl group or a phenethyl group, and R ² is a hydrogen atom or 1 to 1 carbon atoms.
An alkyl group of 6, a phenyl group or a phenethyl group,
a is a number of 2 to 200. ), And an organohydrogenpolysiloxane having at least two hydrosilyl groups in one molecule, and /
Or (2) General formula: (However, R ¹ is an alkyl group having 1 to 6 carbon atoms, a phenyl group or a phenethyl group, and R ² is a hydrogen atom or 1 to 1 carbon atoms.
An alkyl group of 6, a phenyl group or a phenethyl group,
b is a number from 1 to 30. ) Has a structural unit represented by
A homopolymer or copolymer of a hydrogen polysiloxane macromonomer having at least one hydrosilyl group in one molecule and at least one (meth) acryloyloxyalkylene group in the middle or at the end of the siloxane skeleton (however, The method for forming a multilayer coating film is characterized by containing no alkenyl group). 5. The method for forming a multilayer coating film according to claim 1, wherein the compound having a plurality of alkenyl groups is an alkenyl group-containing polyether resin, an alkenyl group-containing polyester resin, or an alkenyl group. A method for forming a multilayer coating film comprising an epoxy resin containing, an alkenyl group containing polycarbonate resin, or an alkenyl group containing acrylic resin. 6. The method for forming a multilayer coating film according to claim 1, wherein the compound having both a plurality of hydrosilyl groups and a plurality of alkenyl groups is (3) ] (However, R ¹ is an alkyl group having 1 to 6 carbon atoms, a phenyl group or a phenethyl group, and R ² is a hydrogen atom or 1 to 1 carbon atoms.
An alkyl group of 6, a phenyl group or a phenethyl group,
b is a number from 1 to 30. ) Has a structural unit represented by
A hydrogen polysiloxane macromonomer having at least one hydrosilyl group in one molecule and having at least one (meth) acryloyloxyalkylene group in the middle or at the end of the siloxane skeleton,
(4) A method for forming a multilayer coating film, which is a copolymer with an alkenyl group-containing acrylic monomer. 7. The method for forming a multilayer coating film according to claim 6, wherein the copolymer further contains an ethylenically unsaturated monomer. 8. The method for forming a multilayer coating film according to claim 1, wherein the functional resin (d) is an organic solvent type or water-based acrylic resin, polyester resin or epoxy resin. And a method for forming a multilayer coating film.