JP2727575B2 - Top coating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a topcoat coating method used for applications such as outer coating of automobiles which form a coating film having excellent appearance and excellent weather resistance.

[Conventional technology]

A so-called wet-on-wet method has been adopted as a top coating method such as automotive outer coating. That is, after a crosslinkable resin paint (base coat) containing a crosslinkable resin such as a hydroxyl group-containing acrylic resin, a hydroxyl group-containing polyester resin or a hydroxyl group-containing alkyd resin and a curing agent as main components, and a metal powder and / or a coloring pigment, is applied. ,
This is a two-coat / one-bake coating method in which a clear coating (top coat) containing a crosslinkable resin and a curing agent as main components is immediately applied to the top coat and cured simultaneously. The purpose of the clear finish is to improve the coating properties such as durability and chemical resistance and the appearance.

In recent years, the requirements for weather resistance of automotive topcoats have become stronger, and higher quality has also been required for the appearance of the coated surface due to the trend toward higher-grade markets.

As a solution to these problems, for example, the addition of an ultraviolet absorber and a light stabilizer to a coating material has already been performed, but it has not reached a sufficient level. or,
As a wet-on-wet clear coat paint, there is also a method using a hydroxyl group-containing fluoroolefin copolymer as a resin component, but also in this case, the gloss value is too low and the appearance of the coated surface is not preferable. Furthermore, there is also known a method of coating and curing by a wet-on-wet method, and then overcoating with a new acrylic clear coat paint and curing, but although the appearance of the painted surface is improved, the durability performance is still not It was not enough.

[Problems to be solved by the invention]

Thus, as long as you follow the conventional technology,
In particular, it has been extremely difficult to provide a cured film with extremely high practicality, which is excellent in appearance and weather resistance.

Accordingly, an object of the present invention is to provide a top coat coating method capable of providing a cured film having extremely high practicality, such as having excellent appearance and weather resistance. It is in.

[Means for solving the problem]

Therefore, the present inventors, in view of the existence of various disadvantages or defects in the conventional technology as described above, and,
Aiming at the problem to be solved by the invention as described above, in order to provide a novel overcoating method that can solve each of the drawbacks or defects in the conventional technology, As a result of repeated investigations, it was found that it is possible to provide an extremely practical cured film that has excellent long-term weather resistance and, in addition, has an excellent coating surface appearance, Finally, the present invention has been completed.

That is, the present invention basically applies a crosslinkable resin paint (base coat) containing a metal powder and / or a color pigment on an object to be coated, and then applies a crosslinkable clear paint on the coated surface obtained as described above. In the topcoat coating method, which comprises coating the coating material I (clear coat I) and crosslinking the coating material, and then coating and crosslinking the crosslinking type clear coating material II (clear coating II).
As the coating material I (A) for the clear coat, a resin composition in a form in which a curing agent (2) is mixed with a hydroxyl group-containing acrylic resin and / or a hydroxyl group-containing fluoroolefin copolymer (1) as a main component, In other words, a resin in which a curing agent (2) is mixed with a hydroxyl group-containing fluoroolefin copolymer (1) as the coating material II (B) for the clear coat, while being used as an essential coating film forming component. An object of the present invention is to provide an overcoating method comprising forming a coating film by using the composition as a main component, that is, as an essential coating film forming component.

In the top coat coating method of the present invention, the base coat paint to be first coated on the coated object includes, as described above, a crosslinkable resin such as a hydroxyl group-containing acrylic resin, a hydroxyl group-containing polyester resin or a hydroxyl group alkyd resin, and an aminoaldehyde resin. The main component is a curing agent reactive with hydroxyl group such as polyisocyanate compound or blocked isocyanate compound, and metal powder such as aluminum, gold, silver, copper, brass and the like, inorganic pigment, organic dye / pigment, flaky mica A conventional wet-on-wet coating for a bakecoat, which contains a color pigment such as a powdered TiO ₂ treated product, can be used as it is.

First, in the method of the present invention, (1) a hydroxyl group-containing acrylic resin and / or a hydroxyl group-containing fluoroolefin copolymer and (2) a curing agent are blended as a cross-linkable clear coating I (clear coat I) after the application of the base coat coating. A paint containing the resin composition obtained as a main component is applied and crosslinked.

The hydroxy group-containing acrylic resin used for the clear coat paint I is 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate,
-Hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, di- 2-hydroxyethyl fumarate, mono-2-hydroxyethyl-monobutyl fumarate, or polypropylene glycol or polyethylene glycol mono (meth) acrylate, Praxel FM or FA monomer (caprolactone-added monomer manufactured by Daicel Chemical Industries, Ltd.) According to a conventional method of a hydroxyl group-containing monomer such as an hydroxyalkyl ester of an α, β-ethylenically unsaturated carboxylic acid or an adduct thereof with ε-caprolactone and another unsaturated monomer described below, for example, in a solvent. Peroxides Te is obtained by radical copolymerization with polymerization initiators such as azo compounds.

As the unsaturated monomer referred to herein, styrene, α-
Aromatic vinyl monomers such as methyl styrene, p-tert-butyl styrene, and vinyl toluene; methyl (meth)
Acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, iso-
Butyl (meth) acrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl acrylate, benzyl (meth) acrylate, dibromopropyl (meth) acrylate or alkoxyalkyl (meth) acrylate (Meth) acrylates; (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid, carboxyl group-containing monomers such as fumaric acid; N-dimethylaminoethyl (meth) acrylamide;
N-diethylaminoethyl (meth) acrylamide, N
-Amino group-containing unsaturated monomers such as -dimethylaminopropyl (meth) acrylamide or N-diethylaminopropyl (meth) acrylamide; dialkylaminoalkyl (meth) such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate A) acrylates; or t-butylaminoethyl (meth) acrylate, t-butylaminopropyl (meth) acrylate, aziridinylethyl (meth) acrylate, pyrrolidinylethyl (meth) acrylate or piperidylethyl (meth) acrylate Monomers containing a basic nitrogen atom such as Dialkyl ((meth) acryloyloxyalkyl) phosphates or (meth) acryloyloxyalkyl acid phosphates represented by the general formula: (R _{1 to} R ₃ , A: supra) dialkyl ((meth) acryloyloxylalkyl) phosphites or (meth) acryloyloxyalkyl acid phosphites, and further the above (meth) acryloyloxyalkyl Acid phosphates or alkylene oxide adducts of acid phosphites, esters of vinyl monomers containing epoxy groups such as glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate with phosphoric acid or phosphorous acid or acid esters thereof Compound 3
Phosphorus-containing monomers such as -chloro-2-acidphosphoxypropyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2- Hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-
Chloro-2-hydroxypropyl (meth) acrylate, di-2-hydroxyethyl fumarate, mono-2-
Α, such as hydroxyethyl-monobutyl fumarate or polyethylene glycol mono (meth) acrylate
β-unsaturated carboxylic acid hydroalkyl esters and maleic acid, succinic acid, phthalic acid, hexahydrophthalic acid,
Adducts with polycarboxylic acid anhydrides such as tetrahydrophthalic acid, benzenetricarboxylic acid, benzenetetracarboxylic acid, "Hymic acid" (product of Hitachi Chemical Co., Ltd.), tetrachlorophthalic acid or dodecinylsuccinic acid; vinyl ethoxy Silicon-based monomers such as silane and α-methacryloxypropyltrimethoxysilane; epoxy group-containing monomers such as glycidyl (meth) acrylate, (β-methyl) glycidyl (meth) acrylate, and (meth) allyl glycidyl ether; maleic anhydride Monomers containing acid anhydride groups such as acid, itaconic anhydride and vinyl ester of trimellitic anhydride; diesters of unsaturated dicarboxylic acid such as fumaric acid or itaconic acid with monohydric alcohol; vinyl acetate, vinyl benzoate;
Vinyl esters such as "Veova"(Shell's vinyl ester); "Viscoat 8F, 8FM, 17FM, 3F or 3F
M "[fluorinated acrylic monomer manufactured by Osaka Organic Chemical Co., Ltd.], perfluorocyclohexyl (meth) acrylate, di-perfluorocyclohexyl fumarate or N-iso-propyl perfluorooctanesulfonamidoethyl (meth) acrylate Fluorinated polymerizable compounds such as vinyl esters, vinyl ethers, (meth) acrylates or unsaturated polycarboxylic esters containing (per) fluoroalkyl groups; or (meth) acrylonitrile, vinyl chloride, vinylidene chloride, etc. There are vinyl monomers having no functional group such as olefins.

If necessary, as a copolymerizable unsaturated group-containing resin,
So-called alkyd resins modified with oils or fatty acids having unsaturated bonds copolymerizable with unsaturated monomers, or unsaturated group-containing polyester resins having unsaturated bonds copolymerizable with unsaturated monomers or unsaturated It is also possible to copolymerize an acrylic resin having an unsaturated bond copolymerizable with the monomer.

Here, the amount of the hydroxyl group-containing monomer used in the hydroxyl group-containing acrylic resin is important, and it is desirable that the hydroxyl value per solid of the acrylic resin falls within the range of 30 to 150 from the viewpoint of coating film performance and the like. In addition, the above-mentioned other unsaturated monomers, copolymerizable unsaturated group-containing resin, the workability of coating, the amount of use of each component and the combination thereof are appropriately determined as necessary from the viewpoint of coating performance such as weather resistance. good.

On the other hand, the hydroxyl group-containing fluoroolefin copolymer is a copolymer containing a fluoroolefin and a hydroxyl group-containing monomer as essential components.

As the fluoroolefin, vinyl fluoride, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, bromotrifluoroethylene, pentafluoropropylene, hexafluoropropylene, or trifluoromethyl trifluorovinyl ether, pentafluoro Representative examples thereof include perfluoroalkyl perfluorovinyl ether such as ethyl trifluorovinyl ether or heptafluoropropyl trifluorovinyl ether, among which tetrafluoroethylene, vinylidene fluoride, chlorotrifluoroethylene, or hexafluoroethylene. The use of fluoropropylene is preferred. These fluoroolefin monomers may be used alone or in combination of two or more.

As the hydroxyl group-containing monomer, 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 3-hydroxybutyl vinyl ether, 2-hydroxy-2-methylpropyl vinyl ether, 5-hydroxypentyl There are vinyl ethers having a hydroxyl group such as vinyl ether, 6-hydroxyhexyl vinyl ether, hydroxyalkyl vinyl ether to which ε-caprolactone is added, and hydroxyalkyl allyl ether to which ε-caprolactone is added.

As the constituent monomers other than the fluoroolefin and the hydroxyl group-containing monomer, vinyl 2,2-dimethylpropanoate, vinyl 2,2-dimethylbuta, which is a monocarboxylic acid vinyl ester having a C _{1 to} C ₁₈ hydrocarbon group. Noate, vinyl 2,2-dimethylpentanoate, vinyl 2,2
-Dimethylhexanoate, vinyl 2,2-dimethylbutanoate, vinyl 2-ethyl-2-methylbutanoate, vinyl 2-ethyl-2-methylbentanoate, vinyl 3-chloro-2,2-dimethyl propanoate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, branched fatty acids vinyl C _9, branched aliphatic carboxylic to C ₁₀ acid vinyl, branched aliphatic carboxylic acids vinyl C ₁ or aliphatic carboxylic acid vinyl esters such as vinyl stearate; cyclohexanecarboxylic acid, vinyl cyclohexanecarboxylate, vinyl benzoate, the p-tert-butyl vinyl benzoate There are carboxylic acid vinyl esters having such a cyclic structure.

Of monocarboxylic acid vinyl esters having a hydrocarbon group of C ₁ -C _18, aromatic carboxylic acid vinyl esters having a hydrocarbon group of C ₁ -C ₁₈ from the viewpoint of appearance improvement of the resulting coating film, in particular It is preferred to use at least one of vinyl benzoate and p-tert-butyl vinyl benzoate.

Other copolymerizable monomers include methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, n-pentyl vinyl ether, n-
Alkyl vinyl ethers or substituted alkyl vinyl ethers such as hexyl vinyl ether, n-octyl vinyl ether, 2-ethylhexyl vinyl ether, chloromethyl vinyl ether, chloroethyl vinyl ether, benzyl vinyl ether or phenylethyl vinyl ether; cycloalkyls such as cyclopentyl vinyl ether, cyclohexyl vinyl ether or methylcyclohexyl vinyl ether Vinyl ethers; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinylmethyldiethoxysilane, vinyltris (β-methoxyethoxy)
Silane, allyltrimethoxysilane, trimethoxysilylethyl vinyl ether, triethoxysilylethyl vinyl ether, methyldimethoxysilylethyl vinyl ether, trimethoxysilylpropyl vinyl ether,
Triethoxysilylpropyl vinyl ether, methyldimethoxysilylpropyl vinyl ether, γ- (meth)
Acryloyloxypropyltrimethoxysilane, γ-
Monomers containing a hydrolyzable silyl group such as (meth) acryloyloxypropyltriethoxysilane or γ- (meth) acryloyloxypropylmethyldimethoxysilane; ethylene, propylene or butene-1
Α-olefins such as vinyl chloride or vinylidene chloride; various halogenated olefins other than fluoroolefins; aromatic vinyl compounds such as styrene, α-methylstyrene or vinyltoluene; methyl methacrylate, ethyl methacrylate, butyl Representative examples are methacrylates such as methacrylate or cyclohexyl methacrylate; and acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate and cyclohexyl acrylate. Further, a carboxyl group-containing monomer such as (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid and fumaric acid can be used in combination.

In preparing the hydroxyl group-containing fluoroolefin copolymer of the present invention from each of the above-mentioned monomer components, the amount of the fluoroolefin used is 15 to 70% by weight, preferably 20 to 60% by weight of all monomers, from the viewpoint of weather resistance and the like. And C ₁
Monocarboxylic acid vinyl ester having a hydrocarbon group of _C18 is 5 to 95% by weight based on the total monomers from the viewpoint of the appearance of the coating film.
It is preferably 10 to 80% by weight, and the hydroxyl group-containing vinyl monomer is preferably 3 to 40% by weight, and more preferably 5 to 40% by weight from the viewpoint of weather resistance.
It is desired to be about 35% by weight.

To prepare the hydroxyl group-containing fluoroolefin copolymer, the method disclosed in JP-A-61-275311, JP-B-60-21686, etc. may be used.

Examples of commercially available products of such a hydroxyl group-containing fluoroolefin copolymer include Fluorate K-700 and K-701 manufactured by Dainippon Ink and Chemicals, Lumiflon LF-100 and LF-200 manufactured by Asahi Glass Co., Ltd. LF-300, LF-400, LF-70
0, Sefral coat manufactured by Central Glass Co., Ltd.

Examples of the curing agent for the clear coating paint I include those reactive with hydroxyl groups, such as aminoaldehyde resins, polyisocyanate compounds or blocked polyisocyanate compounds. First, typical aminoaldehyde resins include: Condensation product obtained by reacting an amino group-containing compound such as melamine, urea, acetoguanamine, benzoguanamine, steroganamin or spiroguanamine with an aldehyde compound such as formaldehyde, paraformaldehyde, acetylaldehyde or glyosazal by a conventional method. Or so-called modified products obtained by etherifying each of these condensation products with monohydric alcohols, but in addition to such representative products, any of those used for paints can be used. Also apply Rukoto can.

Representative examples of polyisocyanate compounds include aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; isophorone diisocyanate, methylcyclohexane-2,4-
(Or 2,6-) diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate) or 1,3-
An alicyclic diisocyanate such as di (isocyanatomethyl) cyclohexane; or an adduct (adduct) of each of these diisocyanates with a polyhydric alcohol or a low molecular weight hydroxyl group-containing polymer; a diisocyanate as described above and water; Examples of the reaction product include a reaction product with a buret agent (a buret compound), and a trimer of a diisocyanate (an isocyanurate compound) as described above.

Further, as a blocked polyisocyanate compound,
Some of the polyisocyanates listed above are blocked with a known blocking agent such as methyl ketoxime or caprolactam.

An appropriate amount of the curing agent is 5 to 100 parts by weight based on 100 parts by weight of the above-mentioned hydroxyl group-containing resin. When the amount of the curing agent used is less than 5 parts by weight, the coating film is liable to fall into a state of insufficient cross-linking.
If the solvent resistance is reduced, and if it exceeds 100 parts by weight, the mechanical properties are undesirably reduced.

The paint for clear coat I of the present invention does not usually contain a pigment, but may contain the metal powder and / or the color pigment used in the paint for base coat to the extent that the transparency of the coating film is maintained. is there.

The coating material for clear coat I of the present invention may further contain various resins, solvents, flow regulators, anti-separation agents, antioxidants, ultraviolet absorbers, light stabilizers or silane coupling agents, if necessary. It is a matter of course that various known and commonly used additives can be added.

Representative examples of the various resins include nitrocellulose, cellulose resins such as cellulose acetate butyrate, vinyl chloride / vinyl acetate copolymer resins, ketone resins,
Examples include petroleum resin, acrylic polymer, oil-free alkyd resin, alkyd resin, and epoxy resin.

Examples of the solvent include hydrocarbons such as toluene, xylene, cyclohexane, n-hexane, and octane;
Ester systems such as methyl acetate, ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate;
Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone and cyclohexanone; dimethylformamide, dimethylacetamide,
Amides such as N-methylpyrrolidone; or alcoholic solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, ethylene glycol monoalkyl ether, or , And mixtures thereof. However, among these solvents, the clear coat I of the present invention is used.
When the above-mentioned curing agent component used in the resin composition for use is a polyisocyanate compound or a blocked polyisocyanate compound, the use of an alcohol solvent should be avoided.

 Next, the clear coat paint II will be described.

The clear coat paint II is obtained by mixing a hydroxyl group-containing fluoroolefin copolymer with a curing agent as a main component. The hydroxyl group-containing fluoroolefin copolymer referred to here can be the same as the hydroxyl group-containing fluoroolefin copolymer used in the clear coat coating material I,
It can be obtained in a similar manner.

As the curing agent, the same curing agent as that used in the above-mentioned clear coat paint I can be used. And
The amount of the aminoaldehyde resin, polyisocyanate compound, or blocked polyisocyanate compound used as the curing agent is appropriately in a range of 5 to 100 parts by weight based on 100 parts by weight of the hydroxyl group-containing fluoroolefin copolymer. . If the amount of the curing agent used is less than 5 parts by weight, the coating film is liable to be inevitably crosslinked, and thus the weather resistance and the solvent resistance are reduced. When the amount exceeds the part, the mechanical properties are undesirably reduced.

As described in the above clear coat paint I, the clear coat paint II of the present invention may contain various resins and solvents, as necessary, a flow regulator, a color separation inhibitor, an antioxidant, and an ultraviolet absorber. It goes without saying that various conventional additives such as an agent, a light stabilizer or a silane coupling agent can be added.

In addition, since the fluoroolefin copolymer has high light transmittance, adding and using an ultraviolet absorber in the coating for clear coat I in order to protect the clear coat I using the copolymer impairs weather resistance. It is preferable to further improve.

In the present invention, the method for forming the coating film is, for example, a surface treatment or, if necessary, a primer, a surfacer, etc., on the surface of the object to be coated, the base coating material is diluted with a diluting solvent as necessary, and The coating is carried out by a usual method so as to have a thickness of 10 to 50 μm, and then the clear coating paint I
Is coated (dry film thickness 5-30 μm) by an ordinary method, and then crosslinked under predetermined conditions. Further, the clear coat paint II is applied by a usual method (5 to 40 μm) and crosslinked under predetermined conditions. Needless to say, the top coat thus obtained is excellent in durability, and has no problem of coating workability of "side" and "drip" as compared with the conventional two-coat one-bake method. Further, a coating film having remarkably excellent gloss, leveling and sharpness can be obtained.

〔Example〕

Next, the present invention will be described more specifically with reference to Reference Examples, Examples and Comparative Examples.

 The parts in the examples represent parts by weight.

Reference Example 1 Preparation Example of Hydroxyl-Containing Fluoroolefin Copolymer In a 2 stainless steel autoclave sufficiently substituted with nitrogen, p-tert-butyl vinyl benzoate 39
0 parts, "VeoVa -9" (vinyl ester of Netherlands Shell Co. C ₉ comprising branched fatty acid) 100 parts of 4-hydroxybutyl vinyl ether 110 parts, 430 parts of butyl acetate, azobisisovaleronitrile (ABVN) 15 parts, 10 parts of tertiary butyl peroxyoctoate (TBPO) and 3 parts of "Sanol LS-765" (an amine compound manufactured by Sankyo) were charged. Then, 400 parts of the liquefied and collected chlorotrifluoroethylene were injected, and the mixture was reacted at 60 ° C. for 15 hours with stirring to obtain a nonvolatile content (NV) of 67%. After cooling to room temperature, 175 parts of xylene was added, and the NV60% was added. Was obtained. Hereinafter, it is abbreviated as copolymer a-1.

<Reference Example 2> Same as Reference Example 1, except that the vinyl monomer was changed to 300 parts of vinyl benzoate, 110 parts of 4-hydroxybutyl vinyl ether, 190 parts of cyclohexyl vinyl ether, and 400 parts of chlorotrifluoroethylene. %, Cooled to room temperature, and added with 194 parts of xylene.
Was obtained. Hereinafter, it is abbreviated as copolymer a-2.

<Reference Example 3> Preparation example of base coat Pigment dispersion was carried out by a normal paint production method so as to have the following ratio, and the compounded mixture was adjusted with a diluting solvent to a viscosity of 20 seconds with a Ford cup No.4. The base coat was used.

"Beccosol CB-931" 108 parts (Alkyd resin manufactured by Dainippon Ink and Chemicals, Inc.) Nonvolatile content 65% "Super Beckamine G-821-60" 50 parts (isobutylated melamine resin manufactured by Dojo Co.) Nonvolatile content 60% "Taipec CR-93" 80 parts (Titanium oxide manufactured by Ishihara Sangyo Co., Ltd.) "Fast Gen Super Red YE" 15 parts (Quinacridone pigment manufactured by Dainippon Ink and Chemicals, Inc.)
258 parts Hereinafter, it is abbreviated as BC-1.

<Reference Example 4> Same as above. A mixture prepared by a usual paint production method in a Ford cup No. 4 with a diluting solvent in a ratio of 11 to 12 so as to have the following ratio.
The viscosity was adjusted to sec. to obtain a base coat.

"Beccolite 57-1054" 72 parts (hydroxyl-containing polyester resin manufactured by Dainippon Ink and Chemicals, Inc.) Nonvolatile content 70% "Super Beckamine L-117-60" 42 parts (n-butylated melamine manufactured by Dojo Co., Ltd.) Resin) 60% non-volatile content 25 parts of CAB-381-2 (cellulose acetate butyrate manufactured by Eastman Kodak Company, USA) 15 parts of Epolen N-10 (wax manufactured by Dojo) 23 parts of Alpaste 1860YL (Toyo) Aluminum paste manufactured by Aluminum Co., Ltd.) Nonvolatile content 65% 177 parts Hereinafter, abbreviated as BC-2.

<Reference Example 5> Same as above. A mixture prepared by a usual paint production method was used as a diluting solvent in a Ford Cup No. 13 to 13 to 14 in a ratio as shown below.
The base coat was adjusted to a viscosity of sec.

"Acrydic 47-712" 160 parts (Hydroxy group-containing acrylic resin manufactured by Dainippon Ink and Chemicals, Inc.) Non-volatile content 50% "Super Beckamine L-117-60" 33 parts "Alpaste 1860YL" 23 parts "Fast Gen" Blue NK ”2 parts (Cyanine Blue manufactured by Dainippon Ink and Chemicals, Inc.) 218 parts Hereinafter, abbreviated as BC-3.

<Reference Example 6> Same as above. A mixture prepared by a normal coating production method in a Ford cup No. 4 with a diluting solvent in a ratio of 11 to 12 s so as to have a ratio as shown below.
The viscosity was adjusted to c to obtain a base coat.

"Acrydic 47-567" 100 parts (manufactured by Dainippon Ink and Chemicals Incorporated hydroxyl group-containing acrylic resin) non-volatile content of 50% "Burnock DN-950" 18 parts (ibid Co. polyisocyanate compound) nonvolatile content of 75% "Tipaque CR-93 "60 parts 178 parts Hereinafter, it is abbreviated as BC-4.

<Reference Example 7> Preparation example of clear coat A mixture prepared by a usual coating method so as to have the following ratio was diluted with a solvent for Ford cup No. 4 for 30 seconds.
The viscosity was adjusted to give a clear coat.

"Acridic A-310" 140 parts (Acrylic resin manufactured by Dainippon Ink and Chemicals, Inc.) Non-volatile content 50% "Super Beckamine L-117-60" 50 parts "Tinuvin 900" 1 part (Ciba Geigy, Switzerland) 1 part of "Sanol LS-765" ( 192 parts of light stabilizer manufactured by Sankyo Co., Ltd., hereinafter abbreviated as CC-1).

<Reference Examples 8 to 15> Ford cup No. 4 was prepared by diluting a mixture prepared by an ordinary coating method so as to have a ratio as shown in Table 1.
To adjust the viscosity to 30 seconds to obtain a clear coat.

Examples 1 to 10 Comparative Examples 1 to 4 Using the base coat and clear coat obtained in Reference Examples 3 to 15 under the conditions shown in Table 2, Examples 1 to 9
In Comparative Examples 1, 2, and 4, on a coated plate obtained by coating an automotive electrodeposition primer and an intermediate coating surfacer on a mild steel plate subjected to a phosphate conversion treatment, in Example 10 and Comparative Example 3, On a coated plate obtained by applying a primer to a polypropylene plate, dry film thickness of 15-20 by air spray
After coating the base coat to make μ, set for 3 minutes and apply clear coat (clear coat I) to dry film thickness
Paint wet-on-wet to be 25-30μ,
After standing for 20 minutes, drying 1 was performed under a predetermined condition using an electric hot air drier. After a further 10 hours, a clear coat (clear coat II) was applied to a dry film thickness of 25-30 μm.
After drying for 2 minutes, it is dried under specified conditions using an electric hot air dryer.
Was done. The evaluation results of the coating film thus obtained are also shown.

[Effects of the Invention] As can be seen from Table 2, the coating film obtained by the coating method of the present invention has a very excellent appearance and weather resistance as compared with the conventional method.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C09D 133/00 C09D 133/00

Claims (4)

(57) [Claims] 1. A cross-linkable resin paint (base coat) containing a metal powder and / or a coloring pigment is applied on an object to be coated, and then the cross-linked clear paint I (clear coat I) is applied to the coated surface thus obtained. ) Is applied and cross-linked, and then a cross-linkable clear coating material II (clear coat II) is applied and cross-linked, wherein the coating material I (A) for the clear coat is a hydroxyl group. As a main component, a resin composition obtained by mixing a curing agent (2) with an acrylic resin and / or a hydroxy group-containing fluoroolefin copolymer (1) is used. As the paint II (B) for the clear coat, A coating film is formed by using a resin composition obtained by mixing a curing agent (2) with a hydroxyl group-containing fluoroolefin copolymer (1) as a main component. And I said, topcoat coating method. 2. A paint I (A) for a clear coat as described above.
And the hydroxyl group-containing fluoroolefin copolymer (1) used as the coating material II (B) for the clear coat contains 15 to 70% by weight of the fluoroolefin and C ₁
5 to 95% by weight of a monocarboxylic acid vinyl ester having a hydrocarbon group of ~ _C18 , 3 to 40% by weight of a hydroxyl group-containing vinyl monomer, and 0 to 0 of other copolymerizable monomers.
Having a monomer composition of 77% by weight,
The topcoat coating method according to claim 1. 3. A paint I (A) for a clear coat as described above.
And the hydroxyl group-containing fluoroolefin copolymer (1) used as the clear coat paint II (B) comprises an aromatic monocarboxylic acid monovinyl ester having a C _{4 to} C ₁₈ hydrocarbon group as an essential component. optionally further vinyl monocarboxylic acids having C ₁ -C ₁₈ comprising aliphatic having a hydrocarbon group and / or cycloaliphatic monocarboxylic vinyl esters including, C ₁ -C ₁₈ comprising hydrocarbon radical 3. The composition according to claim 1, wherein the monomer composition comprises 5 to 95% by weight of the ester, 3 to 40% by weight of the hydroxyl group-containing vinyl monomer, and 0 to 77% by weight of the other copolymerizable monomer. Top coating method described in. 4. A paint I (A) for a clear coat as described above.
And the hydroxyl group-containing fluoroolefin copolymer (1) used as the clear coat paint II (B) is a vinyl benzoate and / or p
-Tert-vinyl benzoate, a monocarboxylic acid vinyl ester having a C _{1 to} C ₁₈ hydrocarbon group
95% by weight, 3 to 40% by weight of hydroxyl-containing vinyl monomer
And a monomer composition consisting of 0 to 77% by weight of other copolymerizable monomers.
4. The method for coating a top coat according to any one of items 1 to 3, above.