JPH08302281A - Coating composition for coating material - Google Patents

Abstract

PURPOSE: To obtain a composition providing a coating film excellent in solvent resistance, stain resistance and chemical resistance, capable of coating without damaging the previous coating film. CONSTITUTION: This composition comprises a fluoroolefin-based copolymer having curable site and a fluorine content of 5wt.% or more, soluble or dispersible in a solvent or dispersion medium containing 30wt.% or more of a paraffin or naphthene-based solvent, and a polyisocyanate-based curing agent having an average isocyanate group content of 1.5wt.% or more, in the equivalent ratio of the copolymer to the curing agent of 100:(10-250).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition for paints. More specifically, the coating film after coating is excellent in solvent resistance, stain resistance and chemical resistance, and even when repairing an old coating film. The present invention relates to a coating composition for a paint, which can paint an old paint film without damaging it.

[0002]

Fluorine-containing resins for paints have high weather resistance,
Since it has excellent characteristics such as long-term use and excellent protection for building and civil engineering structures, it requires significantly less maintenance such as cleaning and repainting, which contributes to improving the living environment and long-lasting fresh colors. It has many advantages such as being stored in a storage medium and free color design (Japanese Patent Laid-Open No. 62-022862, etc.). Conventionally, in a coating composition for a coating material containing such a fluorine-containing resin, a paraffinic solvent or a naphthenic solvent-soluble one-liquid type using a solvent mainly containing a paraffinic solvent or a naphthenic solvent is used. Known (Japanese Patent Laid-Open No. 63-
1997770).

[0003]

However, the two-pack type containing a curing agent usually uses a large amount of a strong solvent such as an aromatic compound such as toluene or an ester compound such as butyl acetate. However, when repairing on the old paint film, there was a defect that the old paint film was damaged. Further, the paraffin-based solvent or naphthene-based solvent-soluble 1-liquid type is cured and does not form a three-dimensional network structure, so that the coating film after film formation has no solvent resistance, and also has poor stain resistance and chemical resistance. It has drawbacks.

[0004]

The present invention has been made to solve the above-mentioned drawbacks, and uses a solvent or dispersion medium containing paraffinic solvent or naphthene-based solvent in an amount of 30% by weight or more of all solvents, Further, it is soluble or dispersible in this solvent or dispersion medium, and contains a fluorine-containing copolymer having a reaction-curable site and having a fluorine content of 5% by weight or more and an isocyanate group in the molecule on average of 1.5 or more. It was found that the above-mentioned problems can be solved by blending a specific amount of the polyisocyanate-based curing agent described above, and the present invention has been completed based on the findings.

That is, according to the present invention, (a) a fluoroolefin copolymer which is soluble or dispersible in the following component (c), has a reaction-curable site, and has a fluorine content of 5% by weight or more, 30 parts of (b) a polyisocyanate curing agent which is soluble or dispersible in the following component (c) and contains 1.5 or more of isocyanate groups in the molecule on average, and (c) a paraffinic solvent or a naphthenic solvent. A novel coating composition comprising a solvent or a dispersion medium in an amount of at least wt% and having a ratio of component (b) of 10 to 250 equivalents to 100 equivalents of component (a). It is a thing. The present invention also provides a coated article obtained by coating the above coating composition for coating on an article. Further, the present invention provides a coated article obtained by re-coating the above coating composition for paint on a coated article. Hereinafter, the present invention will be described in detail.

(A) in the coating composition for paints of the present invention
The component can be dissolved or dispersed in a solvent or a dispersion medium containing paraffinic solvent or naphthenic solvent in an amount of 30% by weight or more of all solvents, has a reactive curable site, and has a fluorine content of 5% by weight or more. It is an olefin-based copolymer. It has this reaction-curable site and has a fluorine content of 5
The fluoroolefin-based copolymer of which the content is at least wt% is a copolymer obtained by polymerization using fluoroolefin as the fluorine-based monomer of the copolymerization raw material. Examples of such fluoroolefins include tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, vinylidene fluoride, vinyl fluoride and the like having 2 to 2 carbon atoms.
The fluoro olefin of 3 is mentioned, Especially, tetrafluoro ethylene and trifluoro ethylene are preferable.

A vinyl-based monomer having a vinyl group or a group containing a vinyl group is preferably used as the copolymerization monomer. Examples of the vinyl-based monomer include vinyl ether, allyl ether, carboxylic acid vinyl ester, carboxylic acid allyl ester, and olefin, and vinyl-based monomers such as vinyl ether and carboxylic acid vinyl ester are particularly preferable. Examples of the vinyl ether include cycloalkyl vinyl ether such as cyclohexyl vinyl ether, nonyl vinyl ether, 2-ethylhexyl vinyl ether, hexyl vinyl ether, n-butyl vinyl ether and t-butyl vinyl ether. Particularly, in order to make it soluble or dispersible in a solvent or dispersion medium having a high content of a paraffinic solvent or a naphthenic solvent, a linear or branched vinyl ether having an alkyl group having 1 to 18 carbon atoms is preferably used. . Examples of the allyl ether include alkyl allyl ethers such as ethyl allyl ether and hexyl allyl ether.
As carboxylic acid vinyl ester or carboxylic acid allyl ester, acetic acid, butyric acid, pivalic acid, crotonic acid,
Examples thereof include vinyl or allyl esters of carboxylic acids such as benzoic acid and maleic acid. Further, as a branched vinyl ester, commercially available Veova-9, -1
0 (both manufactured by Shell Chemical Co., Ltd.) may be used.
Examples of olefins include ethylene and isobutylene. The above-mentioned copolymerization monomers may be used alone or in combination of two or more.

The fluoroolefin copolymer used in the present invention has a curing reactive site. Such a curing reactive site may be one that reacts with a curing agent to form a crosslink. The curing reactive site can be appropriately selected depending on the combination with a curing agent, but typical examples thereof include a hydroxyl group, a carboxyl group, a hydrolyzable silyl group, a glycidyl group, an epoxy group, an amino group and the like. As a method of introducing such a curing reactive site, there is a method of copolymerizing a monomer having a curing reactive site during a copolymerization reaction.

Examples of such a monomer having a curing reactive site include hydroxyethyl vinyl ether and 4-
Having a hydroxyalkyl vinyl ether such as hydroxybutyl vinyl ether and cyclohexanediol monovinyl ether, a hydroxyalkyl allyl ether such as 2-hydroxyethyl allyl ether, and a hydroxyl group-containing vinyl carboxylate such as vinyl hydroxyalkyl crotonate or a hydroxyl group such as allyl ester Monomers, monomers having carboxylic acid groups such as crotonic acid vinyl ester, monomers having hydrolyzable silyl groups such as triethoxyvinylsilane, glycidyl vinyl ether, glycidyl allyl ether,
Examples thereof include a monomer having an epoxy group such as β-methylglycidyl ether, and a monomer having an amino group such as aminopropyl vinyl ether and aminopropyl vinyl ether.

It is also possible to introduce a curing reactive site by post-reaction after polymerization. As this method, for example, a method of introducing a hydroxyl group by saponifying a polymer obtained by copolymerizing a carboxylic acid vinyl ester,
A method of reacting a polyvalent carboxylic acid or an anhydride thereof with a polymer having a hydroxy group to introduce a carboxyl group, a method of reacting an isocyanate alkoxysilane to introduce a water-decomposable silyl group, and reacting a polyvalent silyl isocyanate compound At least, a method of introducing an isocyanate group can be mentioned.

The number of curing reactive sites in the fluoroolefin copolymer corresponds to 1 to 150 mg / g of paraffinic solvent based on the resin solid content in terms of chemical reaction equivalent of potassium hydroxide. Alternatively, it is preferable as a naphthene-based solvent-soluble type, more preferably 10 to 70 mg / g. Polymerize these polymers in a paraffinic solvent or a naphthenic solvent, or by replacing a part or all of the solvent or dispersion medium with a paraffinic solvent or a naphthenic solvent after the polymerization to make a weak solvent type varnish. You can Further, in the fluoroolefin-based copolymer, the vinyl monomer as a copolymerization raw material is not always an essential copolymerization component. In that case, a homopolymer of fluoroolefin or a copolymer obtained by combining several kinds of fluoroolefin may be used. The fluorine content of the fluoroolefin copolymer used in the present invention is 5% by weight or more, preferably 10% by weight or more,
It is particularly preferably 20 to 35% by weight. The fluoroolefin copolymer may be used alone or in combination of two or more.

Other resins may be used in combination with the fluoroolefin copolymer. As the other resin, acrylic resin, polyester resin, acrylic polyol resin, polyester polyol resin, urethane resin and other resins and fluorine resin having no functional group, for example, Kainer 500, Kainer SL, Kainer ADS (above manufactured by Atochem Co.) , Floren (manufactured by Japan Synthetic Rubber Co., Ltd.) and the like. Further, these other resins may have a curing reactive functional group. The other resins may be used alone or in combination of two or more. The amount of the other resin to be blended may be appropriately selected within a range that does not impair the effects of the present invention, but is usually preferably 1 to 200 parts by weight with respect to 100 parts by weight of the fluoroolefin copolymer.

In the coating composition for coating material of the present invention, as a solution or dispersion containing a fluoroolefin copolymer, Lumiflon LF200, Lumiflon LF400, Lumiflon LF500, Lumiflon LF544 and the like (these are products of Asahi Glass Co., Ltd., trade name ), Fluoronate (manufactured by Dainippon Ink and Chemicals, Inc., trade name), Cefralcoat (manufactured by Central Glass Co., Ltd., trade name), Zaffron 200, 300 (trade name, manufactured by Toagosei Co., Ltd.), Zeffle GK5100 (manufactured by Daikin Industries, Ltd., Take out only the resin content of commercial products such as product name) and add paraffin solvent or naphthene solvent to 30
It is also possible to use those dissolved or dispersed in a solvent or dispersion medium containing at least wt%. The component (b) used in the coating composition for coating material of the present invention is soluble or dispersible in a solvent or a dispersion medium containing 30% by weight or more of a paraffinic solvent or a naphthene type solvent, and has an average isocyanate group in the molecule. It is a polyisocyanate curing agent containing 1.5 or more.

Typical examples thereof include ethylene diisocyate, butylene diisocyanate, hexamethylene diisocyanate, decamethylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate, 4,4-methylene-bis ( Fail isocyanate), ω · ω-diisocyanate diethyl xylene, 4
-Polyisocyanates such as 4-methylene-bis (cyclohexyl isocyanate) and triphenylmethane triisocyanate. Furthermore, these isocyanates have a polyisocyanate obtained by addition reaction with water or a polyol such as ethylene glycol glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, or a polyisocyanate having a buret structure, or an allophanate structure. A polyisocyanate or a polyisocyanate having an isocyanurate structure is used. Further, in order to improve the dilutability of the polyisocyanate, those obtained by reacting alcohols and mercaptans and introducing a hydrocarbon chain are also suitably used.

As a curing agent for the coating composition for paints of the present invention, an isocyanate group in the molecule is soluble or dispersible in a solvent or a dispersion medium containing 30% by weight or more of a paraffinic solvent or a naphthenic solvent. Then, a polyisocyanate-based curing agent containing 1.5 or more or an isocyanate group thereof blocked with caprolactam, isophorone, β-diketone, or the like can be used. These curing agents can be used in combination of several kinds. The mixing ratio of the curing agent is 10 with respect to 100 equivalent parts of the fluoroolefin copolymer having a fluorine content of 5% by weight or more.
To 250 equivalent parts, more preferably 50 to 150
It is the equivalent part. When the amount of the curing agent is less than 10 equivalent parts, the solvent resistance and hardness are insufficient, and when the amount of the curing agent exceeds 250 equivalent parts, the workability and impact resistance may decrease. Here, the curing agent is 10 to 250 equivalent parts, preferably 5 parts with respect to 100 equivalent parts of the fluoroolefin copolymer.
The term "0 to 150 equivalent parts" means that "the number of reaction-curable sites in the fluoroolefin-based copolymer / the number of isocyanate groups in the polyisocyanate-based curing agent" is 0.1 to 2.5, preferably 0.5. It means that it is about 1.5.

The component (c) used in the coating composition for paints of the present invention is a solvent or dispersion medium containing 30% by weight or more of a paraffinic solvent or a naphthene type solvent. As the paraffinic solvent or naphthenic solvent, those having an aniline point of 10 ° C. or higher are preferable, and those having an aniline point of 10 to 70 ° C. are more preferable. Specific examples of paraffinic solvents include n-pentane, isopentane, n-hexane, 2-methylpentane, 3-methylpentane, 2,
2-dimethylbutane, n-heptane, 2-methylhexane, 3-ethylpentane, 2,2-dimethylpentane,
2,3-dimethylpentane, n-octane, 2-methylheptane, n-nonane, 2-methyloctane, 2,3,3
4-trimethylpentane, n-decane, 2-methylnonane, 2-methyldecane, and a mixture thereof such as mineral spirit and mineral terpene.
Of these, n-pentane, isopentane, n-hexane and mineral terpenes are preferable, and mineral terpene is particularly preferable.

Specific examples of the naphthene-based solvent include cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane,
Examples thereof include 1,3-dimethylcyclohexane, 1,4-dimethylcyclohexane, cycloheptane, methylcycloheptane, cyclooctane, methylcyclooctane, cyclononane, cyclodecane, and mixtures thereof. Of these, cyclohexane and cyclodecane are preferable. The paraffinic solvent and the naphthenic solvent may be used alone or in combination. Examples of the solvent or dispersion medium that can be used in combination with the paraffinic solvent or the naphthenic solvent include aromatic hydrocarbons such as toluene and xylene, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ethyl acetate and butyl acetate. Ester solvent or dispersion medium, n-butanol,
Examples thereof include alcohol solvents such as isobutanol and dispersion media.

The amount of the paraffinic solvent or naphtheneic solvent in the mixture of these solvent or dispersion medium and paraffinic solvent or naphtheneic solvent is 30% by weight or more, preferably 50% by weight or more, particularly preferably 70% by weight. % Or more. The aniline point of this mixture is 10 to 70.
C. is preferred. The content ratio of the solvent or the dispersion medium containing 30% by weight or more of the paraffinic solvent or the naphthenic solvent in the coating composition for coating material of the present invention is not particularly limited and may be appropriately selected according to the viscosity of the coating composition for coating material. However, the total amount of the components (a) and (b) is usually 100.
The amount is 80 to 600 parts by weight, preferably 100 to 250 parts by weight, based on parts by weight.

Coloring pigments or dyes, silane coupling agents for improving the adhesion of coatings, ultraviolet absorbers, etc. may be added to the coating composition for coating materials of the present invention. As the coloring pigment or dye, for example, carbon black having good weather resistance, an inorganic pigment such as titanium oxide, phthalocyanine blue, phthalocyanine green, quinacridone red, indanthrene orange, an organic pigment or dye such as isoindolinone yellow, etc. Can be mentioned. A curing accelerator, a light stabilizer, a matting agent and the like may be appropriately added to the coating composition for coating material of the present invention, if necessary. As the curing accelerator, dibutyltin dilaurate or the like can be used, and when the curing agent is an amino resin, an acidic catalyst such as paratoluenesulfonic acid can be used. Examples of the light stabilizer include hindered amine light stabilizers, and specific examples thereof include MARX.
LA62 (product name by Adeka Argus Chemical) and MAR
Examples include XLA67 (manufactured by ADEKA ARGUS CORPORATION, trade name), TINUVIN 292, TINUVIN 144, CGL-123, TINUVIN 440 (manufactured by Ciba Geigy) and the like. Examples of the matting agent include ultrafine synthetic silica, and when the matting agent is used, an elegant semi-glossy or matte finish coating film can be formed.

A surfactant may be added to the coating composition for paint of the present invention. Since the surfactant controls the surface tension, it is effective for adjusting the surface concentration of a specific component.
These surfactants may be any of nonionic, cationic and anionic types, such as ROLEX ASE (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), fluorosurfactant Surflon (manufactured by Asahi Glass Co., Ltd.), acrylic type Modaflow (manufactured by Monsanto). , Product name), and Leofat series (made by Kao, product name). The coating composition for coating material of the present invention can be produced by mixing the above-mentioned essential components and various additives added as necessary. The order of mixing and the order of addition are not particularly limited and may be a mixing order in which the components (a) and (c) are mixed in advance and the component (b) is mixed therein. The mixing order may be such that the component (b) is mixed in advance and then the component (c) is mixed.

The method of coating using the coating composition for coating material of the present invention includes spray coating, dipping method, roll coater,
Any method such as a flow coater can be applied. Examples of the material of the article to be coated include inorganic materials such as concrete, natural stone and glass, and metals such as iron, stainless steel, aluminum, copper, brass and titanium. Also suitable are organic substrates, such as plastics, rubbers, adhesives, wood and the like. In addition, organic-inorganic composite materials such as FRP, resin reinforced concrete, and fiber reinforced concrete are also suitable. The coating composition for paints according to the invention is particularly suitable for coating on already formed coatings. This coating film may be formed by a coating material containing the component (a) in the present invention,
It may be a coating film formed by a paint having a relatively poor solvent resistance such as a paint containing the above-mentioned other resin that can be used in combination with the component (a), a synthetic resin-blended paint, a phthalic acid resin paint, a chlorinated rubber paint, an emulsion paint. Also, the articles to be coated include transportation equipment such as automobiles, trains, and aircraft, bridge members,
Civil engineering materials such as steel towers, waterproofing sheets, industrial equipment such as tanks and pipes, building exteriors, doors, window gates, monuments, building materials such as poles, road medians, guardrails, soundproof walls and other road materials, Communication equipment, electrical and electronic parts, etc.

[0022]

EXAMPLES Next, the present invention will be described in more detail based on examples. The invention is in no way limited by these examples. (Example 1) Fluoroolefin copolymer (chlorotrifluoroethylene / ethyl vinyl ether / hydroxybutyl vinyl ether / cyclohexyl vinyl ether = 50/2/8/40 mol%) A part of the hydroxyl groups of the copolymer is reacted with succinic anhydride. Tata, hydroxyl value: 40,
100 parts by weight of acid value: 1, fluorine content: 22% by weight and Shoishi Solvent (a mixture solvent of Showa Shell Sekiyu's aromatic hydrocarbon content of 30% by weight and an aniline point of 44.5 ° C, mainly of paraffin) To 100 parts by weight of the resin liquid, 3 parts by weight of TINUVIN 1130 (manufactured by Ciba-Geigy, benzotriazole-based UV absorber), CGL123 (0.15 parts by weight of Ciba-Geigy, hindered amine-based light stabilizer), C
54 parts by weight of R95 (titanium oxide manufactured by Ishihara Sangyo Co., Ltd.) and 8 parts by weight of Shoishi Solvent were mixed and dispersed to obtain a composition for colored coating composition. Duranate TSA-100 (NCO%: 2), which is a polyisocyanate curing agent containing an average of 1.5 or more isocyanate groups in the molecule, is used.
0.8, the average number of NCO groups in the molecule: 3) 14.4 parts by weight (100 parts by weight of the curing agent to 100 parts by weight of the fluoroolefin copolymer) are mixed before coating to prepare a coating liquid ( Hereinafter referred to as composition A). Apply this to a steel member after 10 years of coating with chlorinated rubber paint at a coating interval of 24 hours.
Painted twice.

(Example 2) Instead of the fluoroolefin copolymer of Example 1, (chlorotrifluoroethylene / 2-ethylhexyl vinyl ether / hydroxybutyl vinyl ether / cyclohexyl vinyl ether = 5)
A product obtained by reacting a part of the hydroxyl groups of 0/20/10/20 mol% copolymer with succinic anhydride, hydroxyl value: 40,
A colored coating composition was obtained in the same manner as in Example 1 except that a copolymer having an acid value of 1 and a fluorine content of 22% by weight) was used, and the composition was applied in the same manner as in Example 1.

(Example 3) The composition (A) of Example 1 was applied to a concrete stand 7 years after the acrylic resin emulsion was applied.

Example 4 Instead of the fluoroolefin copolymer of Example 2, (chlorotrifluoroethylene / 2-ethylhexyl vinyl ether / hydroxybutyl vinyl ether / cyclohexyl vinyl ether = 5)
One obtained by reacting succinic anhydride with part of the hydroxyl groups of 0/15/20/15 mol% copolymer, hydroxyl value: 10
0, acid value: 1, fluorine content: 22% by weight) A composition similar to that of Example 1 was applied, except that an epoxy resin primer coated on a new iron member was coated. .

Comparative Example 1 A colored coating composition was obtained in the same manner as in Example 1 except that xylene was used as the shoishi solvent, and the composition was applied in the same manner as in Example 1.

Comparative Example 2 A colored coating composition was obtained in the same manner as in Example 1 except that the curing agent was not added, and the composition was applied in the same manner as in Example 1.

(Comparative Example 3) A coating composition was obtained in the same manner as in Example 1 except that xylene was used in place of Shoishi Solvent, and this composition was applied to concrete after 7 years of acrylic resin emulsion coating. Painted on the frame. The results of the above Examples and Comparative Examples are shown in Table 1. In the table, the solvent resistance was evaluated by rubbing the coating film aged for one week with gauze containing xylene 20 times and dissolving it x, and not dissolving it was marked o. The weather resistance was evaluated as ◯ when the gloss retention was 80% or more after 3000 hours with a sunshine weather meter. As for workability, the finished appearance of the coating film was observed after 1 day of coating.

[0029]

[Table 1]

EFFECT OF THE INVENTION The coating composition for paints of the present invention has excellent solvent resistance, stain resistance and chemical resistance after coating, and particularly damages the old coating when repairing it. Can be painted without.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shunichi Kodama, 3-4474 Tsukakoshi, Sachi-ku, Kawasaki-shi, Kanagawa 2 Asahi Glass Co., Ltd. 2 Asahi Glass Co., Ltd. Tamagawa Branch Room (72) Inventor Takashi Takayanagi 3-474 Tsukakoshi, Sachi-ku, Kawasaki City, Kanagawa Prefecture 2 Asahi Glass Co., Ltd. Tamagawa Branch Room

Claims (7)

[Claims] 1. A fluoroolefin copolymer which is soluble or dispersible in the following component (c), has a reactive curable site, and has a fluorine content of 5% by weight or more, (b):
30% by weight or more of a polyisocyanate curing agent that is soluble or dispersible in the following component (c) and contains 1.5 or more of isocyanate groups on average in the molecule, and (c) a paraffinic solvent or a naphthene solvent. A coating composition for a coating composition comprising a solvent or a dispersion medium containing the component (b), wherein the ratio of the component (b) is 10 to 250 equivalents relative to 100 equivalents of the component (a). 2. The coating composition for a coating composition according to claim 1, wherein the fluoroolefin-based copolymer is a copolymer of fluoroolefin and a vinyl-based monomer. 3. The coating composition for coating composition according to claim 2, wherein the vinyl-based monomer is a vinyl-based monomer containing a hydroxyl group. 4. The coating composition for coating composition according to claim 1, wherein the fluoroolefin copolymer is a copolymer having a carboxyl group. 5. The coating composition for coating material according to claim 1, wherein the curing agent as the component (b) is a polyvalent isocyanate curing agent. 6. A coated article obtained by coating the coating composition for paint according to any one of claims 1 to 5 on the article. 7. A coated article obtained by recoating the coating composition for a coating composition according to claim 1 on a coated article.