JPH09192599A - Method for coating metal material and coated metal material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a coating film with excellent weatherability and corrosion resistance by using a compsn. wherein a compd. with an oxirane ring and a compd. with an aminoalkyl group and a hydrolyzable silyl group are essential ingredients as a primer when a fluorinated coating compsn. is applied on a metal material. SOLUTION: In a method for coating a metal material, when the metal material is coated with a fluorinated coating compsn. composed of ingredients [1]-[4], a compsn. wherein a compd. with an oxirane ring and a compd. with an aminoalkyl group and a hydrolyzable silyl group are essential ingredients is used as a primer. In this case, [1] is a fluorinated copolymer composed of 30-60 mole % fluoroolefin monomer unit (1), 3-30 mole % hydroxyl group-contg. vinyl monomer unit (2), and 10-67 mole % vinyl monomer unit except (1) and (2), and [2] is a crosslinking agent with a functional group being reactive with hydroxyl group and [3] is an org. solvent and [4] is an ultraviolet absorbing agent and a light stabilizer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for coating a metal material, and more particularly to a coating method for forming a coating film having excellent weather resistance and corrosion resistance.

[0002]

2. Description of the Related Art In building materials, metals such as stainless steel, brass and aluminum, and alloys thereof have high designability by taking advantage of the appearance of the metal base. However, when these metal materials are used outdoors, they often pose a problem because the appearance is often damaged by corrosion. On the other hand, a fluorine-containing coating composition is known as a coating composition having excellent weather resistance and chemical resistance, and is used as a top coat in coating metal materials, concrete and the like. However, the fluorine-containing coating composition cannot be said to have sufficient adhesion to these substrates, and in a place exposed to high temperature and high humidity, despite coating the fluorine-containing coating composition, Rust was generated due to the decrease in adhesiveness, and the original weather resistance and corrosion resistance performance of the fluorine-containing coating composition were not sufficiently exhibited.

[0003]

The problem to be solved by the present invention is to form a coating film excellent in weather resistance and corrosion resistance,
It is to provide a method for coating a metal material.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, have completed the present invention. That is, the present invention provides the metal material with the following (1) to
When a fluorine-containing coating composition comprising the component (4) is applied, a composition having an oxirane ring-containing compound and a compound having an aminoalkyl group and a hydrolyzable silyl group as essential components is used as a primer. It is a coating method of a metal material. (1) a) Fluoroolefin monomer unit: 30 to 60
Mol% b) Hydroxyl group-containing vinyl monomer unit: 3 to 30 mol% c) Vinyl monomer unit other than the above: 10 to 67 mol% Fluorine-containing copolymer (2) Reactive with hydroxyl group Crosslinking agent having functional group (3) Organic solvent (4) Ultraviolet absorber and light stabilizer

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. As the metal material in the present invention, iron, copper,
Any metal such as aluminum, tin, zinc and titanium and alloys such as stainless steel, aluminum alloy, brass and bronze can be used without particular limitation. Also,
It can be used with or without the metal surface treatment, and for example, it may be subjected to chemical treatment such as degreasing treatment, chromate treatment and phosphoric acid treatment, and plating treatment such as zinc plating and tin plating. <Primer> Examples of the composition used for the primer in the present invention include the composition described in JP-A-3-231906. Examples of the compound having an oxirane ring, which is one of the essential components of the primer, include bisphenol A type and F type epoxy resins, polyglycidyl amine type epoxy resins, novolac type epoxy resins, alcohol type epoxy resins, ester type epoxy resins and alicyclic rings. Formula epoxy resin etc. are mentioned. Further, an organosilicon compound having an oxirane ring and an alkoxy group can be used, and specific examples include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane. , Γ-glycidoxypropylmethyldiethoxysilane and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane.

Specific examples of the compound having an aminoalkyl group and a hydrolyzable silyl group, which is another essential component of the primer, include aminomethyltriethoxysilane, 3-aminopropyltriethoxysilane and 3-aminopropyltriethoxysilane. Methoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N-
Examples thereof include compounds such as (2-aminoethyl) -3-aminopropylmethyldimethoxysilane and N- (2-aminoethyl) -3-aminopropylmethyldiethoxysilane.

The mixing ratio of the compound having an oxirane ring to the compound having an aminoalkyl group and a hydrolyzable silyl group is 1 mole of the amino group of the compound having an aminoalkyl group and a hydrolyzable silyl group to the oxirane ring. The oxirane ring of the compound having is preferably 0.2 to 0.9 mol. Oxirane ring compound is 0.2
When the amount is less than the molar amount, the film-forming property is deteriorated, so that the rust-preventive property is hardly exhibited, and when it is more than 0.9 mol, the coating film becomes brittle.

The composition used for the primer in the present invention can be obtained by mixing the above-mentioned two types of components and the components described below. When used as a primer, it is preferred that the oxirane ring of the compound having an oxirane ring and the amino group of the compound having an aminoalkyl group and a hydrolyzable silyl group undergo a condensation reaction before being applied to a metal substrate. Although this condensation reaction proceeds sufficiently even at room temperature, the composition may be heated to accelerate the reaction faster, and the temperature is preferably about 40 to 100 ° C.

The composition may be diluted with an organic solvent used in paints. As the organic solvent that can be used, aromatic organic solvents such as toluene, xylene and Solvesso; esters such as ethyl acetate and butyl acetate; acetone, methyl ethyl ketone, methyl isobutyl ketone,
Ketones such as cyclohexanone, methyl amyl ketone, ethyl amyl ketone and isophorone; cellosolve acetates such as ethylene glycol monomethyl ether acetate and ethylene glycol monobutyl ether acetate. These organic solvents can be used alone or in combination of two or more. When an organic solvent is used, the ratio of the essential components in the composition is 1 to 3.
It is preferably 0% by weight.

It is also possible to add an amine-based crosslinking agent and a phosphoric acid-based rust inhibitor as other components to the composition. Further, a small amount of water may be added for the purpose of increasing the molecular weight by the siloxane bond. However, since these compounds reduce the stability of the composition at room temperature when added, it is preferable to use them immediately after addition.

<Fluorine-containing coating composition> The (1) fluorine-containing copolymer, which is one of the components of the fluorine-containing coating composition in the present invention, is described in, for example, JP-A-3-231906. Examples thereof include a fluorinated copolymer. Examples of the (a) fluoroolefin monomer in the fluorine-containing copolymer include monofluoroethylene, difluoroethylene, trifluoroethylene, tetrafluoroethylene,
Examples thereof include chlorotrifluoroethylene and hexafluoropropylene, and chlorotrifluoroethylene is particularly preferable in terms of copolymerizability and easy handling. The proportion of the fluoroolefin monomer in the fluorocopolymer is 30 to 60 mol%, preferably 40 to 60 mol%. If it is less than 30 mol%, the weather resistance will be reduced to 60
If it is more than mol%, the solubility in organic solvents may decrease.

Examples of the (b) hydroxyl group-containing vinyl monomer in the fluorine-containing copolymer include 2-hydroxyethyl crotonate, 4-hydroxybutyl crotonate and 2
Hydroxyl group-containing crotonic acid esters such as hydroxypropyl crotonate; hydroxyl group-containing (meth) acrylic acid esters such as 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate; 2
Hydroxyl group-containing vinyl ethers such as hydroxyethyl vinyl ether and 4-hydroxybutyl vinyl ether; hydroxyl group-containing allyl ethers such as 2-hydroxyethyl allyl ether, 4-hydroxyethyl allyl ether and diethylene glycol monoallyl ether;
2-hydroxyethyl (meth) acrylamide and 4
And hydroxyl group-containing (meth) acrylamides such as hydroxyethyl (meth) acrylamide. These hydroxyl group-containing monomers can be used alone or in combination of two or more kinds. The proportion of the hydroxyl group-containing vinyl monomer is 3 to 30 mol% in the fluorocopolymer. If it is less than 3 mol%, the reactivity with the curing agent is lowered, so that the coating film strength may be insufficient, and if it exceeds 30 mol%, the weather resistance and the water resistance may be lowered.

Examples of the vinyl monomer other than the above (c) in the fluorine-containing copolymer include carboxylic acid vinyl esters, vinyl ethers, norbornadiene compounds, unsaturated carboxylic acids and their anhydrides.
The ratio of these monomers in the fluorocopolymer is 10 to 6
It is 7 mol%.

Specific examples of vinyl carboxylate ethers include vinyl acetate, vinyl propionate, vinyl caproate, vinyl pivalate, Veova-9 and Veova-1.
0 (manufactured by Shell Chemical Co., Ltd.), aliphatic vinyl esters, vinyl cyclohexanecarboxylate, vinyl 4-cyclohexylcarboxylate such as vinyl 4-t-butylcyclohexanecarboxylate, vinyl benzoate and p.
Examples thereof include aromatic vinyl carboxylates such as -t-butylbenzoic acid.

Specific examples of vinyl ethers include alkyl vinyl ethers such as ethyl vinyl ether and butyl vinyl ether, and cycloalkyl vinyl ethers such as cyclohexyl vinyl ether.

As unsaturated carboxylic acids, acrylic acid,
Examples thereof include crotonic acid, maleic acid, itaconic acid and vinylacetic acid. In the case of an unsaturated carboxylic acid, the water resistance is lowered when the amount used is large, so that it is preferably 5 mol% or less.

The number average molecular weight of the fluorine-containing copolymer is preferably 2000 to 100,000 in terms of polystyrene by gel permeation chromatography, from the viewpoint of the strength of the coating film to be formed and the handleability of the coating composition. . The glass transition temperature of the fluorinated copolymer is preferably 10 ° C. or higher so that the formed coating film exhibits blocking resistance.

Examples of the crosslinking agent (2) having a functional group reactive with a hydroxyl group in the present invention include hexamethylene diisocyanate, isophorone diisocyanate and polyisocyanates such as dimers and trimers thereof, and blocked isocyanates; methyl. Examples thereof include melamine chloride, butylated melamine, urea resins, and aminoblast resins such as benzoguanamine. Further, a curing accelerator such as dibutyltin dilaurate and p-toluenesulfonic acid may be used in combination. In the case of the isocyanate-based and blocked isocyanate-based crosslinking agents, the amount of the crosslinking agent used is NCO / OH = 1 / 1.2 to 1/0 in terms of the molar ratio of the hydroxyl group and the isocyanate group in the fluorocopolymer. 0.7 is preferable. In the case of an aminoblast resin-based cross-linking agent, fluorine-containing copolymer / aminoblast resin = 4/1 to 10/1
It is preferable to mix them in a (weight ratio).

When a cross-linking agent that does not react with hydroxyl groups at room temperature, such as an aminoblast resin and a blocked isocyanate cross-linking agent, is used, it may be mixed at the time of preparing a coating composition, but when a polyisocyanate cross-linking agent is used, the hydroxyl group may be mixed at room temperature. Since it reacts with, it is preferable to use it by mixing with other components immediately before coating.

As the organic solvent (3) in the present invention,
It can be used without limitation as long as it can dissolve the above-mentioned fluorine-containing copolymer, and one having a boiling point of 60 ° C. or higher is preferable. Specifically, aromatic organic solvents such as toluene, xylene and solvesso; esters such as ethyl acetate and butyl acetate; ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl amyl ketone and ethyl amyl ketone; n-butanol and i
-Alcohols such as propanol; methyl cellosolve,
Examples thereof include cellosolve-based solvents such as n-butyl cellosolve and n-butyl cellosolve acetate; propylene glycol-based solvents such as propylene bricol monomethyl ether, propylene bricol monobutyl ether, and propylene glycol monomethyl ether acetate. These solvents can be used alone or in combination of two or more kinds.

The ultraviolet absorber (4) and the light stabilizer in the present invention are essential components because they have the effects of suppressing the decomposition of the fluorinated copolymer and preventing ultraviolet light from reaching the primer. Examples of the ultraviolet absorber include a benzophenone compound, a benzotriazole compound, an oxalic acid anilide compound, and a benzotriazine compound.

Examples of the benzophenone compound include 2-
Hydroxy-4-methoxybenzophenone, 2-hydroxy-4-ethoxybenzophenone, 2-hydroxy-
4-butoxybenzophenone, 2,4-dihydroxybenzophenone and the like can be mentioned.

The benzotriazole-based compound is 2
-(2'-hydroxyphenyl) benzotriazole,
2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-5′-methylphenyl) -5-carboxylic acid butylbenzotriazole, 2- (2′-hydroxy-5 ′) -Methylphenyl)
-5,6-dichlorobenzotriazole, 2- (2'-
Hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5 ′
-Di- (1,1-dimethylbenzyl) benzotriazole, 2- (2'-hydroxy-5'-methylphenyl)
-5-ethyl sulfone benzotriazole and 2-
(2'-hydroxy-3'-methyl-5'-t-butylphenyl) -5-chlorobenzotriazole and the like can be mentioned.

As the oxalic acid anilide compound, N-
(2-Ethoxyphenyl) -N '-(4-isododecylphenyl) ethanediamide, N- (2-ethoxyphenyl) -N'-(2-ethylphenyl) ethanediamide and N- (2-ethoxy-5-t -Butylphenyl-
N '-(2-ethylphenyl) ethanediamide etc. are mentioned.

As the benzotriazine-based compound, 2-
(2-Hydroxy-4- (2-hydroxy-3-tridecanooxypropyl) phenyl) -4,6-bis (2,4-
Dimethylphenyl) -1,3,5-triazine and the like can be mentioned. The preferred addition amount of these ultraviolet absorbers is 2 to 10 based on the total amount of the fluorocopolymer and the crosslinking agent.
% By weight.

Specific examples of the light stabilizer in the present invention include 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,2).
6,6-pentamethyl-4-piperidyl) sebacate,
Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 8-acetyl-3
-Dodecyl-7,7,9,9-tetramethyl-1,3,3
Examples thereof include amine compounds such as 8-triazaspiro (4,5) decane-2,4-dione and bis (N-octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate. The preferable addition amount of these light stabilizers is 0.5 to 5% by weight based on the total amount of the fluorocopolymer and the crosslinking agent.

The fluorine-containing coating composition of the present invention can be applied not only to a clear coating composition but also to a color clear coating composition containing a small amount of coloring content. As the coloring pigment used at this time, those used in ordinary paints can be used. For example, inorganic pigments such as titanium oxide, red iron oxide, yellow iron oxide, calcined pigments and pearl pigments; metallic pigments such as aluminum flakes and stainless flakes;
Examples include organic pigments such as phthalocyanine blue, quinacridone red, isoindolinone and carbon black, and volume pigments such as calcium carbonate. Further, as the matting agent, polyethylene wax, polypropylene wax and silica-based matting agent can be added.

The fluorine-containing coating composition of the present invention contains additives such as a leveling agent, a slip agent, an anti-sagging agent, an antifoaming agent, a color separation preventing agent, an antioxidant, a heat stabilizer and a silane coupling agent. May be. Further, a pigment oxidizing agent may be added at the time of dispersing the pigment in the color clear coating composition. From the viewpoint of workability, the proportion of the coating film-forming component (fluorine-containing polymer + crosslinking agent + ultraviolet absorber + light stabilizer) in the prepared coating composition is preferably 20 to 70% by weight.

The coating method of the present invention will be described below. <Coating Method> 1) Coating of Primer Coating of the primer can be performed by a dipping method, a roll coater, a spray, a brush or the like. The dry film thickness of the primer is 0.5 to 20 from the balance of corrosion resistance and adhesion.
μm is desirable. It is considered that the reason why good adhesion is exhibited by using the primer is that the hydrolyzable silyl group portion in the primer composition forms a chemical bond with the metal surface. For that purpose, it is preferable to apply the primer and leave it for one day or more at room temperature before applying the fluorine-containing coating composition. Alternatively, it is desirable to heat the base material to 100 ° C. or higher at the time of coating the primer or at the time of coating the fluorine-containing coating composition after air-drying the primer. In the method of coating the fluorine paint after air-drying the primer, when the film thickness of the primer is about 2 μm or more, it is desirable to heat and dry the primer when it is coated. This is because if the fluorine-containing coating composition is applied when the film thickness of the primer is large, lifting of the primer occurs and the finished appearance deteriorates.

2) Coating of Fluorine-Containing Coating Composition The fluorine-containing coating composition can be coated by spraying, a roll coater, brush coating or the like. The film thickness of the fluorine-containing coating composition is preferably 10 to 50 μm from the viewpoint of balance between undercoat protection and cost. When the primer is dried at room temperature, it is preferable to coat the fluorine-containing coating composition at least one day after coating the primer in order to obtain good adhesion. The fluorinated coating composition after coating may be dried by either room temperature drying or heat drying. When the primer film thickness is thin, the fluorine-containing coating composition can be applied immediately after air drying. However, in this case, since the coating film of the fluorine-containing coating composition reduces the water absorption of the primer, the chemical bond forming reaction between the primer and the metal is hindered. In this case, good adhesion can be obtained by heating. Heating is preferably 100 ° C. or higher.
When the film thickness of the primer is thicker than about 2 μm, when the fluorine-containing coating composition is applied on the primer which is just air-dried, not only the gloss is slightly decreased and the finished appearance is deteriorated, but also the effect of improving the adhesion is small. In order to avoid this, it is advisable to heat and dry the primer before applying the fluorine-containing coating composition. After heating and drying, the fluorine-containing coating composition is applied, but the applied fluorine-containing coating composition may be dried under any of drying conditions such as room temperature drying and heat drying.

[0031]

EXAMPLES The present invention will be described more specifically below with reference to Examples and Comparative Examples. <Preparation of Primer> As a compound having an oxirane ring, Epicoat 828 (bisphenol A type epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd .: molecular weight 335) was used as a compound having an aminoalkyl group and a hydrolyzable silyl group, and γ-amino was used. The following formulation with propyltriethoxysilane was heated at 80 ° C. for 1 hour to prepare a primer.・ Epicoat 828 6.70 g (0.02 mol) ・ γ-aminopropyltriethoxysilane 11.05 g (0.05 mol) ・ Methyl ethyl ketone 70.00 g ・ Toluene 10.00 g

<Preparation of Fluorine-Containing Coating Composition 1> Chlorotrifluoroethylene / vinyl propionate / vinyl versatic acid (Veoba 9) / 2-hydroxyethyl crotonic acid = 49/23/18/10 (mol%). Using a xylene solution (solid content 60% by weight) of a fluorine-containing copolymer (number average molecular weight Mn = 13000, hydroxyl value OHV = 53, glass transition temperature Tg = 28 ° C.), a heat-curable clear coating composition having the following composition A composition was prepared. -Fluorine-containing copolymer xylene solution (solid content 60% by weight) 100.0 g 2- (2'-hydroxy-3 ', 5'-di- (1,1-dimethylbenzyl) benzotriazole 4.0 g- Bis (N-octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate 0.8 g-0.1% toluene solution of dibutyltin dilaurate 6.0 g-Coronate 2515 (manufactured by Nippon Polyurethane Industry Co., Ltd.) Blocked isocyanate) 24.3 g-Solvesso 150 30.9 g-Cyclohexanone 21.2 g

<Preparation of Fluorine-Containing Coating Composition 2> Composition 1
Using the same fluorine-containing copolymer as above, a room temperature curable coating composition was prepared with the following formulation. -Fluorine-containing copolymer xylene solution (solid content 60% by weight) 100.0 g 2- (2'-hydroxy-3 ', 5'-di- (1,1-dimethylbenzyl) benzotriazole 4.0 g- Bis (N-octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate 0.8 g-Dibutyltin dilaurate 0.1% toluene solution 6.0 g-Duranate TPA (Hexa manufactured by Asahi Kasei Corporation) Methylenediisocyanate isocyanurate type trimer) 10.8 g-xylene 27.8 g-toluene 11.9 g-MIBK 6.7 g

Using degreased SUS304 plate (HL finish, size 0.6 × 200 × 300 mm), test plates of Examples 1-6 and Comparative Examples 1-2 were prepared by the following method. Example 1 The primer was applied by a bar coater to a dry film thickness of 5 μm. After heating and drying at 240 ° C. for 30 seconds, the fluorine-containing coating composition 1 is dried with a bar coater to a film thickness of 25 to 30.
It was coated so as to have a thickness of μm, and was heated and dried at 220 ° C. for 120 seconds.

Example 2 The above primer was applied by a bar coater to a dry film thickness of 5 μm. After drying at room temperature for 2 days, the fluorine-containing coating composition 2 was applied with a bar coater to a dry film thickness of 25 to 30 μm, and dried at room temperature for 1 week.

Example 3 Toluene / methyl ethyl ketone = 30
It was diluted with a thinner of / 70% by weight to a coating component of 5% by weight and coated with a bar coater so that a dry film thickness was about 1 μm. After standing at room temperature for 1 hour, the fluorine-containing coating composition 1 was applied with a bar coater to a dry film thickness of 25 to 30 μm, and dried by heating at 220 ° C. for 120 seconds.

EXAMPLE 4 Toluene / methyl ethyl ketone = 30
It was diluted with a thinner of / 70% by weight to a coating component of 5% by weight and coated with a bar coater so that a dry film thickness was about 1 μm. After standing at room temperature for 1 hour, the fluorine-containing coating composition 2 was applied with a bar coater to a dry film thickness of 25 to 30 μm, and dried by heating at 130 ° C. for 30 minutes.

Example 5 The same primer as in Example 1 except that the heat treatment was not applied was applied by a bar coater to a dry film thickness of about 5 μm. After standing at room temperature for 1 hour, the fluorine-containing coating composition 2 was applied with a bar coater to a dry film thickness of 25 to 30 μm, and dried at room temperature for 1 week.

Example 6 The above primer was applied by a bar coater to a dry film thickness of 5 μm. After air-drying for 30 minutes, the fluorine-containing coating composition 1 was applied with a bar coater to a dry film thickness of 25 to 30 μm, and dried by heating at 220 ° C. for 120 seconds.

Comparative Example 1 Without coating the primer, only the fluorine-containing coating composition 1 was coated with a bar coater to a dry film thickness of 25 to 30 μm, and then dried by heating at 220 ° C. for 120 seconds.

Comparative Example 2 Without coating the primer, only the fluorine-containing coating composition 2 was coated with a bar coater to a dry film thickness of 25 to 30 μm, and then dried at room temperature for one week.

TEST EXAMPLE Test plates coated according to Examples 1-6 and Comparative Examples 1-2 were subjected to the following tests. The test results are shown in Table 1 below. -Gloss value: 60 ° -60 ° gloss value of the vertical grain of stainless steel-Adhesion: Residual rate of cross-cut cellophane tape peeling test after immersion in boiling water for 5 hours-Corrosion resistance: CASS test (JIS H8681) 30
Appearance after 0 hours ・ Weather resistance: Sunshine weather meter test (JIS
K5400) Gloss retention after 3000 hours

[0043]

[Table 1]

[0044]

According to the present invention, a coating film having excellent weather resistance and corrosion resistance can be obtained, and it is possible to perform coating that makes the best use of the appearance of a metal material.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location C09D 127/12 PFH C09D 127/12 PFH (72) Inventor Hiroshi Inukai Funami-cho, Minato-ku, Aichi Prefecture Address 1 1 Toagosei Co., Ltd. Nagoya Research Institute

Claims (2)

[Claims] 1. When a fluorine-containing coating composition comprising the following components (1) to (4) is applied to a metal material, a compound having an oxirane ring and a compound having an aminoalkyl group and a hydrolyzable silyl group are used. A method for coating a metal material, which comprises using a composition as an essential component as a primer. (1) a) Fluoroolefin monomer unit: 30 to 60
Mol% b) Hydroxyl group-containing vinyl monomer unit: 3 to 30 mol% c) Fluorine-containing copolymer composed of vinyl monomer units other than the above: 10 to 67 mol% (2) Reactive with hydroxyl group Crosslinking agent having functional group (3) Organic solvent (4) Ultraviolet absorber and light stabilizer 2. A coated metal material having a coating film formed by the coating method according to claim 1.