JP2020090102A - Coated metal plate - Google Patents

Abstract

To provide a coated metal plate having high alga-proofness.SOLUTION: A coated metal plate of the invention includes a metal plate, and a coating layer which covers the metal plate and contains a pyrithione compound and no resin coating material. It is preferable that the pyrithione compound is within a range of 0.5-15 mass% with respect to whole coating layer. It is preferable that the pyrithione compound contains a pyrithione metal salt.SELECTED DRAWING: None

Description

The present invention relates to a coated metal plate including a coating layer and a metal plate, and more particularly to a coated metal plate having algae control performance.

A coated metal plate including a coating layer and a metal plate is widely used for building materials. Especially when the coated metal plate is used as an exterior material, its surface is required to have antifouling property.

As a method for improving the antifouling property of a coated metal plate, for example, in Patent Document 1, an inorganic compound containing silicic acid and/or a compound having a hydrolyzable silyl group is compounded in an organic clear paint or an organic enamel paint, Then, it is disclosed that a coating film is formed by applying the coating material to a metal plate and drying the coating, and then subjecting the coating film to heat treatment. In this method, the hydrophilicity of the coating film can be improved to improve the raindrop contamination resistance.

JP, 2006-102671, A

In recent years, as the use of coated metal plates has expanded, attention has been paid to contamination that cannot be prevented only by improving the hydrophilicity of the coating film. For example, it has been pointed out that greenish stains adhere to the coated metal plate. As confirmed by the present inventors, this green stain was caused by algae adhering to the coating film. Thus, the present inventors have come to recognize the need for a coated metal plate having a property that algae is unlikely to adhere (algae resistance).

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a coated metal plate having high algae resistance.

The coated metal plate according to the present invention is characterized by including a metal plate and a coating layer containing a pyrithione compound and covering the metal plate.

According to the present invention, a coated metal plate having high algae resistance can be obtained.

An embodiment of the present invention will be described below.

The coated metal plate according to this embodiment includes a metal plate and a coating layer that covers the metal plate, and the coating layer contains a pyrithione compound. As a result, a coated metal plate having extremely high algae resistance can be obtained.

The metal plate is a suitable steel plate made of, for example, stainless steel. The metal plate may be a plated steel plate such as a hot dip galvanized steel plate or a hot dip galvanized steel plate.

A layer other than the coating layer, such as a chemical conversion treatment layer and a layer formed from a resin coating, may be formed on the metal plate.

The chemical conversion treatment layer is a layer formed by a known chemical conversion treatment. As a treatment agent (chemical conversion treatment agent) for forming the chemical conversion treatment layer, for example, a phosphoric acid-based treatment agent such as a zinc phosphate treatment agent, an iron phosphate treatment agent; a metal oxide such as cobalt, nickel, tungsten, or zirconium. Oxide treatment agent containing singly or in combination; treatment agent containing inhibitor component for preventing corrosion; treatment agent combining binder component (organic, inorganic, organic-inorganic composite) and inhibitor component; inhibitor component And a metal oxide; a treating agent in which a binder component is combined with a sol such as silica, titania, or zirconia; and a treating agent in which the components of the above-exemplified treating agents are further combined.

Examples of the zirconium oxide-containing oxide treating agent include water and a water-dispersible polyester urethane resin, a water-dispersible acrylic resin, a zirconium compound such as sodium zirconium carbonate, and a hindered amine. The treating agent prepared by The water-dispersible polyester-based urethane resin is synthesized, for example, by reacting a polyester polyol with a hydrogenated isocyanate and by self-emulsifying by copolymerizing dimethylolalkyl acid. With such a water-dispersible polyester urethane resin, high water resistance is imparted to the chemical conversion treatment layer without using an emulsifier, and the corrosion resistance and alkali resistance of the hot-dip metal sheet are improved.

Before forming the chemical conversion treatment layer, or instead of forming the chemical conversion treatment layer, the metal plate may be subjected to plating treatment such as nickel plating treatment and cobalt plating treatment.

The chemical conversion treatment layer may be formed using a chemical conversion treatment agent by a known method such as a roll coating method, a spray method, a dipping method, an electrolytic treatment method or an air knife method. After application of the chemical conversion treatment agent to the metal plate, if necessary, steps such as standing at room temperature and drying or baking with a heating device such as a hot air oven, an electric oven, or an induction heating oven may be added. A curing method using energy rays such as infrared rays, ultraviolet rays and electron rays may be applied. The temperature and the drying time at the time of drying are appropriately determined depending on the type of the chemical conversion treatment agent used and the required productivity. The chemical conversion treatment layer thus formed is a continuous or discontinuous film on the plating layer. The thickness of the chemical conversion treatment layer is appropriately determined according to the type of treatment, the required performance and the like.

The layer formed of the resin coating material may be formed of a known coating material such as an epoxy resin coating material, a polyester resin coating material and a fluororesin coating material. The coated metal plate may include a layer formed of one resin paint, or may include a layer formed of a plurality of resin paints.

The coating layer is formed so as to cover the metal plate. The coating layer may be in direct contact with the metal plate, or a layer other than the coating layer may be interposed between the coating layer and the metal plate. For example, when the chemical conversion treatment layer is formed on the metal plate, the coating layer may be formed so as to cover the chemical conversion treatment layer. The coating layer contains a pyrithione compound. This coating layer is formed from a coating composition containing a pyrithione compound. The coating layer containing the pyrithione compound remarkably improves the algae resistance of the coating layer.

Examples of the pyrithione compound include zinc pyrithione, copper pyrithione, sodium omadine (Omadine(R)), pyridine-N-oxide disulfide, omazine (Omadine(R)) disulfide, 2,2'-dithio-pyridine-1,1. -Containing at least one component selected from the group consisting of dioxide and pyridine-2-thione-N-oxide. The pyrithione compound preferably contains a pyrithione metal salt, and particularly preferably contains zinc pyrithione. Zinc pyrithione not only effectively improves the algal resistance of the coated metal plate, but also does not easily affect the appearance of the coated metal plate because it is difficult to color the coating layer. Furthermore, even when the coated metal plate is exposed outdoors, zinc pyrithione does not easily cause discoloration of the coating layer. Therefore, zinc pyrithione can ensure good weather resistance of the coated metal sheet.

The pyrithione compound is preferably contained in the range of 0.5 to 15 mass% with respect to the entire coating layer. When the pyrithione compound is 0.5% by mass or more, the adhesion of algae to the coating layer is significantly suppressed. When the content of the pyrithione compound is 15% by mass or less, the coating property of the coating composition containing the pyrithione compound becomes good, the coating layer can be easily formed from the coating composition, and the coating layer and the metal plate as the base thereof. Adhesion with the like becomes good. It is more preferable that the pyrithione compound is in the range of 0.5 to 5% by mass. When the content of the pyrithione compound is 5% by mass or less, the pyrithione compound is less likely to reduce the flexibility of the coating layer, and thus the coating layer is less likely to be cracked even when mechanically working such as bending the coated metal plate.

The coating layer may contain a silicon compound. When the coating layer contains a silicon compound, the hydrophilicity of the coating layer is increased, and thus the antifouling property of the coating layer is improved. The silicon compound is preferably 2.0% by mass or more based on the entire coating layer. In this case, the coating layer has a particularly high antifouling property. In particular, the silicon compound content is preferably in the range of 2.0 to 2.5 mass% with respect to the entire coating layer. If the silicon compound content exceeds 2.5% by mass, the effect of improving the antifouling property will be saturated.

The silicon compound preferably contains at least one of a silicate compound and a cured product thereof. The silicate compound and its cured product can form at least a part of the mother phase of the coating layer.

The silicate compound can contain an appropriate compound having a hydrolyzable silyl group. For example, the silicate-based compound can contain at least one of an organosilicate represented by the following general formula (1) and a hydrolyzed condensate of the organosilicate.
(R ₁ ) _m -Si-(OR ₂ ) _4-m (1)
R ₁ and R _{2 in} formula (1) are each independently a hydrogen atom, or an alkyl group or aryl group having 1 to 10 carbon atoms. m is 0 or 1. Examples of the silicate compound include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltriethoxysilane, phenyltriethoxysilane and octyltriethoxysilane. Silane, dodecyltriethoxysilane, dimethylcyclolosilane, trimethylchlorosilane, methyltrichlorosilane, dimethylvinyltriethoxysilane and fluorine-modified compounds or condensates thereof, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxy Silane coupling agents such as propyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane and fluorine-modified compounds thereof, and a group consisting of condensates thereof. It may contain one or more compounds selected from

The silicate compound may be incorporated in the skeleton of the organic resin in the coating composition and the coating layer. That is, the coating composition may contain an organic resin modified with a silicate compound, and the coating layer may contain at least one of an organic resin modified with a silicate compound and a cured product thereof.

Examples of the organic resin modified with a silicate-based compound include a silicate-modified polyester resin (silicate-modified polyester resin). The silicate-modified polyester resin is produced, for example, by reacting an appropriate amount of a carboxyl group-containing polyester resin, a hydroxyl group-containing epoxy group-containing polyester resin, an epoxy group-containing vinyl polymer and a silicate compound. At this time, an ester bond is formed by the reaction between the carboxyl group of the polyester resin and the epoxy group of the epoxy group-containing polyester resin having a hydroxyl group. The silicate compound is incorporated into the resin skeleton by reacting with the hydroxyl group of the epoxy group-containing polyester resin. Thereby, a silicate modified polyester resin is obtained.

The epoxy group-containing vinyl polymer is a polymer of a vinyl monomer having an epoxy group, or a polymer of a vinyl monomer having an epoxy group and another vinyl monomer. The vinyl monomer having an epoxy group includes, for example, glycyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, glycyl (meth)allyl ether and 3,4-epoxycyclohexylmethyl (meth)allyl ether. It can contain at least one component selected from the group consisting of: In particular, the epoxy group-containing vinyl polymer is higher in radical polymerization and reactivity between epoxy groups/carboxyl groups, and is a (meth)acrylic acid ester such as glycidyl (meth)acrylate and 3,4-epoxycyclohexylmethyl ( It is more preferable to contain at least one of (meth)acrylate.

The epoxy group-containing vinyl polymer is a copolymer obtained by copolymerizing a vinyl monomer having an epoxy group with another vinyl monomer (hereinafter, also referred to as a second monomer). It is preferably a polymer. Examples of the second monomer include (meth)acrylic acid esters and the like. The second monomer preferably has a reactive functional group in addition to the saturated hydrocarbon group, and specifically, selected from the group consisting of a hydroxyl group, an acetal group, a cyclocarbonate group, and a blocked carboxyl group. It is preferable to have at least one group of It is preferable that the reactive functional group does not show strong reactivity with the epoxy group under the copolymerization conditions with the vinyl monomer having an epoxy group.

Examples of (meth)acrylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, (meth ) It contains at least one component selected from the group consisting of stearyl acrylate, 2-hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate.

The second monomer is selected from the group consisting of itaconic acid, maleic acid, esters such as fumaric acid, styrene, vinyltoluene, dimethylstyrene, nuclear-substituted styrene such as ethylstyrene, acrylonitrile, vinyl acetate, and vinyl chloride. At least one component may be contained.

The silicate-modified resin may contain various resins such as a silicate-modified acrylic resin in addition to the silicate-modified polyester resin.

When the coating composition contains a silicate-based compound or a silicate-modified organic resin, the coating composition preferably further contains an acidic catalyst together with water. In this case, the hydrolysis reaction of the silicate compound or the like is promoted when the coating composition is applied and formed into a film. The acidic catalyst contains at least one component selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid and p-toluenesulfonic acid.

It is also preferred that the silicon compound contains silica particles. That is, it is also preferable that the coating layer and the coating composition contain silica particles. The silica particles are preferably colloidal silica. A specific example of the colloidal silica is Snowtex manufactured by Nissan Chemical Industries, Ltd. The particle size of colloidal silica is within the range of 2 to 100 nm, for example. From the viewpoint of surface coating, it is preferable that the particle size of colloidal silica is small. The silicon compound may contain colloidal silica having different particle sizes.

The silicon compound is a compound consisting of silicon, oxygen, hydrogen such as orthosilicic acid, metasilicic acid, silica gel; a silicate compound combined with aluminum, magnesium, iron, etc., for example, a naturally occurring compound such as feldspar, mica, cement. , Artificial compounds such as glass and enamel may be contained. The silicate compound may contain silicate glass, and in this case, it may contain silicate glass in the form of fine powder, fiber or the like.

The coating layer and the coating composition may contain hydrotalcites. In this case, the hydrophilicity of the coating layer is further improved, and thus the antifouling property of the coating layer is further improved. Hydrotalcites are compounds represented by the following general formula (2).
[M 2 ⁺ _1-X M ³⁺ _X (OH) ₂ ] ^X+ [A ^n- _X/n ·mH ₂ O] ^X -... (2)
In the general formula (2), M ²⁺ is a divalent metal ion, for example, a group consisting of Mg ²⁺ , Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ and Zn ^2+. It is at least one metal ion selected from. M ³⁺ is a trivalent metal ion, for example, at least one metal ion composed of Al ³⁺ , Fe ³⁺ , Cr ³⁺ , Co ³⁺ and In ³⁺ . A ^n- is OH ⁻ , F ⁻ , Cl ⁻ ,
It represents an n-valent anion such as Br ⁻ , NO ₂ ⁻ , CO ₃ ²⁻ , SO ₄ ²⁻ , Fe(CN) ₃ ³⁻ , CH ₃ COO ⁻ , oxalate ion, salicylate ion and the like. Moreover, X shows a value larger than 0 and not larger than 0.33. It is preferable that the hydrotalcites contain magnesium aluminum hydroxide hydroxide carbonate hydrate (Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O) which is a particularly highly stable substance. It is preferable that the hydrotalcites are not dehydrated. This makes it possible to improve the hydrophilicity of the coating layer as compared with hydrotalcites that have been dehydrated.

The hydrotalcites are, for example, DHT-6 (manufactured by Kyowa Chemical Industry Co., Ltd.) having an average particle size of about 3 μm, Kyoward 100, Kyoward 200, and Kyoward in the form of particles having an average particle size of about 20 to 300 μm and a polycrystalline structure. 300, KYOWARD 400, KYOWARD 500PL, KYOWARD 500SH, KYOWARD 500SN, KYOWARD 1000, KYOWARD 2000 (all manufactured by Kyowa Chemical Industry Co., Ltd.), KYOWARD having an average particle size of 20 to 300 μm and an amorphous structure 600, Kyo word 700, etc. can be contained. In particular, it is preferable that the hydrotalcites contain at least one of Kyoward 200 and Kyoward 300 that have not been dehydrated. In this case, hydrotalcite has an anion substitution property, and the carbonic acid group is replaced by another anion. The mixing of hydrotalcites with other components in the coating composition is carried out under neutral or acidic conditions, preferably under acidic conditions. When mixed under alkaline conditions, aggregation may occur due to the properties of hydrotalcites. A liquid exhibiting acidity including a binder may be used to control the acidity, or an acid may be separately added during mixing to maintain the acidity.

The coating layer may contain at least one of a resin component and a cured product thereof as a component constituting the mother phase of the coating layer. In this case, the coating composition may contain an appropriate resin component.

The resin component can contain, for example, at least one resin selected from the group consisting of acrylic resin, urethane resin, alkyd resin, epoxy resin, amino resin, polyester resin, phenol resin, silicone resin and fluororesin. In particular, it is preferable that the resin component contains at least one of a highly versatile polyester resin and a fluororesin having excellent corrosion resistance and weather resistance.

The polyester resin is, for example, a polycondensation product of monomers containing a dicarboxylic acid and a diol.

Examples of the dicarboxylic acid include fatty acid dicarboxylic acids having 2 to 22 carbon atoms such as succinic acid, adipic acid, azelaic acid, sebacic acid and decamethylenedicarboxylic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid; Contains at least one component selected from the group consisting of alicyclic dicarboxylic acids such as phthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, 1,4-cyclohexanedicarboxylic acid, and 1,3-cyclohexanedicarboxylic acid .. The dicarboxylic acid may include an ester-forming derivative of dicarboxylic acid (a compound which is an ester of dicarboxylic acid and forms a polyester resin by a transesterification reaction, an acid anhydride, etc.).

The diol can contain, for example, a fatty acid diol having 2 to 22 carbon atoms, and more specifically, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1, It may contain at least one component selected from the group consisting of 4-butanediol, 2,3-butanediol, neopentyl glycol, 1,6-hexanediol, diethylene glycol and pentanediol. The diol may contain an ester-forming derivative of the diol (a compound such as a diol ester which forms a polyester resin by a transesterification reaction).

The monomer for obtaining the polyester resin includes a compound having a carboxyl group having three or more functional groups and a compound having a hydroxyl group for the purpose of reducing the crystallinity of the polyester resin, introducing a carboxyl group into the polyester resin, and the like. At least one of the above may be included. For example, when the monomer contains trimellitic acid, the polyester resin may contain a carboxyl group-containing linear polyester resin having a structure in which trimellitic acid is added to a hydroxyl group existing at the end of a linear molecular chain. it can. Further, the monomer contains at least one component selected from the group consisting of trimethylolpropane, 1,2,3-hexanetriol, trimellitic acid and pyromellitic acid, so that the polyester resin contains a resin having a branch. You can also do it. When the monomer contains a trifunctional carboxylic acid such as trimellitic acid or trimethylolpropane, the polyester resin may contain a resin whose crystallinity is reduced.

When the resin component contains a polyester resin, the resin component may further contain a curing agent that undergoes a thermosetting reaction with the polyester resin. The curing agent is preferably a compound having at least one reactive functional group selected from the group consisting of a carboxyl group, a carboxylic acid anhydride group and a carboxyl group blocked with an alkyl vinyl ether compound. Examples of the compound having a carboxyl group include succinic acid, malonic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, decamethylenedicarboxylic acid, dimer acid, phthalic acid, maleic acid, trimellitic acid, pyromellitic acid, tetrahydrophthalic acid. It contains at least one component selected from the group consisting of acids, hexahydrophthalic acid and methylhexahydrophthalic acid.

The fluororesin preferably contains a resin having a hydrophilic group. The fluororesin may contain a resin having a hydrophilic group and a resin having no hydrophilic group.

The fluororesin preferably contains a fluorinated olefin polymer. The fluorinated olefin-based polymer is a polymer of a fluorinated olefin monomer. The fluorinated olefin monomer is preferably dispersed or dissolved in an organic solvent.

Examples of the fluorinated olefin-based polymer include polytetrafluoroethylene, polyvinylidene fluoride, (ethylene/tetrafluoroethylene) copolymer, (vinylidene fluoride/tetrafluoroethylene) copolymer, (tetrafluoroethylene/hexafluoropropylene). ) Containing at least one selected from the group consisting of a copolymer, polyfluorovinyl ether, polychlorotrifluoroethylene, (ethylene/chlorotrifluoroethylene) copolymer and (fluorovinyl ether/tetrafluoroethylene) copolymer it can. Commercially available products of fluorinated olefin polymers include paints such as "Lumiflon" manufactured by Asahi Glass Co., Ltd., "Fluoronate" manufactured by DIC Co., Ltd., "Zaflon" manufactured by Toagosei Co., Ltd., "Zeffle" manufactured by Daikin Industries, Ltd. A resin may be used. It is preferable that the fluororesin contains a vinylidene fluoride-based polymer from the viewpoint of good compatibility with an acrylic component, good solubility in a solvent, and high hydrophilicity.

The fluororesin is a copolymer of an ethylenically unsaturated monomer containing a fluorinated (meth)acrylate and a hydrophilic structural unit-containing ethylenically unsaturated monomer (hereinafter referred to as a hydrophilic structure-containing copolymer). It is also preferable to contain. It is also preferable that the fluororesin contains a hydrophilic structure-containing copolymer and a fluorinated olefin-based polymer.

In the hydrophilic structure-containing copolymer, the hydrophobic segment and the hydrophilic segment are present in the same chain. By using this hydrophilic structure-containing copolymer, the hydrophilicity of the coating layer is improved. The hydrophilic segment is a segment having a hydrophilic group such as polyalkylene oxide, hydroxyl group, carboxyl group, sulfonyl group, phosphate, amino group, isocyanate group, glycidyl group, ammonium salt, and various metal salts in the molecule. Is.

The fluorinated (meth)acrylate for obtaining the hydrophilic structure-containing copolymer preferably has an acrylic ester group and its related group. The following compounds may be mentioned as specific examples of the fluorinated (meth)acrylate.
CH ₂ =CHCOOCH ₂ CH ₂ C ₈ F ₁₇
CH ₂ =CHCOOCH ₂ CH ₂ C ₁₂ F ₂₅
CH ₂ =CHCOOCH ₂ CH ₂ C ₁₀ F ₂₁
CH ₂ =CHCOOCH ₂ CH ₂ C ₆ F ₁₃
CH ₂ =CHCOOCH ₂ CH ₂ C ₄ F ₉
CH ₂ =CFCOOCH ₂ CH ₂ C ₆ F ₁₃
CH ₂ =CHCOOCH ₂ CF ₃
CH ₂ =CHCOOCH ₂ C ₈ F ₁₇
CH ₂ =CHCOOCH ₂ C ₂ 0F ₄₁
CH ₂ =CFCOOCH ₂ C ₂ F ₅
CH ₂ =CHCOOCH ₂ (CH ₂ ) ₆ CF(CF ₃ ) ₂
CH ₂ =CHCOOCH ₂ (CF ₂ ) ₂ H
CH ₂ =CHCOOCH ₂ (CF ₂ ) ₄ H
CH ₂ =CHCOOCH ₂ CF ₃
CH ₂ =CHCOOCH ₂ CH(OH)CH ₂ C ₈ F _{17
CH 2 = CHCOOCH 2 CH 2 N} (C 3 H 7) SO 2 C 8 F 17
_{CH 2 = CHCOOCH 2 CH 2 N} (C 2 H 5) COC 7 F 15
CH ₂ =CHCOO(CH ₂ ) ₈ N(CH ₃ )COC ₁₂ F ₂₅
CH ₂ =CHCOO(CH ₂ ) ₂ N(CF ₂ ) ₈ CF(CF ₃ ) _{2
CH 2 = C (CH 3)} COOCH 2 CH 2 C 8 F 17
_{CH 2 = C (CH 3)} COOCH 2 CH 2 C 12 F 25
_{CH 2 = C (CH 3)} COOCH 2 CH 2 C 10 F 21
_{CH 2 = C (CH 3)} COOCH 2 CH 2 C 6 F 13
CH ₂ =C(CH ₃ )COOCH ₂ CH ₂ C ₂₀ F _{41
CH 2 = C (CH 3)} COOCH 2 CH 2 C 4 F 9
_{CH 2 = C (CH 3)} COO (CH 2) 6 C 10 F 21
_{CH 2 = C (CH 3)} COOCH 2 CF 3
_{CH 2 = C (CH 3)} COOCH 2 C 8 F 17
_{CH 2 = C (CH 3)} COOCH 2 C 2 0F 41
_{CH 2 = C (CH 3)} COOCH 2 CF (CF 3) 2
_{CH 2 = C (CH 3)} COOCH 2 CFHCF 3
CH ₂ =C(CH ₃ )COOCHCF ₂ CFHCF ₃
CH ₂ =C(CH ₃ )COOCH ₂ (CF ₂ ) ₂ H
_{CH 2 = C (CH 3)} COO (CF 2) 4 H
_{CH 2 = C (CH 3)} COO (CF 2) 6 H
_{CH 2 = C (CH 3)} COOCH 2 CH (OH) (CH 2) 4 C 18 F 37
_{CH 2 = C (CH 3)} COOCH 2 CH 2 N (CH 3) SO 2 C 6 F 13
CH ₂ =C(Cl)COO(CH ₂ ) ₆ NHSO ₂ C ₁₂ F ₂₅
Of these compounds, only one kind may be used, or two or more kinds may be used in combination.

The hydrophilic structural unit-containing ethylenically unsaturated monomer for obtaining the hydrophilic structure-containing copolymer is, for example, a monovalent or divalent carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, fumaric acid or itaconic acid. An α,β-ethylenically unsaturated carboxylic acid; a 2-hydroxyethyl ester, a 2-hydroxypropyl ester, a 4-hydroxybutyl ester, and the like; Containing at least one component selected from the group consisting of glycidyl esters of (meth)acrylic acid such as glycidyl (meth)acrylate; and monomers containing polyalkylene oxide such as repeating units such as ethylene oxide and propylene oxide in the side chain it can.

The ethylenically unsaturated monomer for obtaining the hydrophilic structure-containing copolymer further includes styrene, nucleus-substituted styrene, acrylonitrile, vinyl chloride, vinylidene chloride, vinyl pyridine, vinyl acetate, etc. Is a (meth)alkyl ester having 1 to 18 carbon atoms, an aminoalkyl ester of (meth)acrylic acid having 1 to 18 carbon atoms, an ether oxygen-containing alkyl ester of (meth)acrylic acid having 1 to 18 carbon atoms, and an alkyl carbon number of It may contain at least one component selected from the group consisting of 1 to 18 alkyl vinyl ethers.

By polymerizing an ethylenically unsaturated monomer by a known polymerization method such as a solution polymerization method, a bulk polymerization method and an emulsion polymerization method by a polymerization mechanism such as radical polymerization, cationic polymerization and anionic polymerization, a hydrophilic structure can be obtained. A containing copolymer is obtained. As the polymerization method, a radical polymerization method is particularly preferable.

It is also preferable that the resin component contains a fluororesin and an acrylic resin. Acrylic resin is preferable in that it has high compatibility with the fluorinated olefin polymer and that the acrylic resin improves the adhesion between the coating layer and the metal plate or the like. The acrylic resin is, for example, a homopolymer or copolymer of a monomer having a (meth)acryloyl group. The monomer having a (meth)acryloyl group is, for example, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, octel (meth)acrylate, stearyl (meth)acrylate, or isoaryl. Stearyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, acrylonitrile, 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate, dibutyl fumarate, dimethyl fumarate And at least one component selected from the group consisting of (meth)acrylic acid.

The coating composition and the coating layer may further contain various additives. As additives, inorganic pigments such as titanium oxide, carbon black, iron oxide, chromate and calcium carbonate; organic pigments such as cyanine green and cyanine blue; metal powders such as aluminum powder, copper powder and nickel powder; deodorant Agent; antistatic agent; silicone oil; fluororesin powder; silicone powder; extender pigment such as talc; antifoaming agent; antirust agent; leveling agent; wax; ultraviolet absorber; coupling agent; surfactant; plasticizer A drying accelerator, a curing catalyst, an organic solvent such as xylene and siloxane, and the like.

A coating layer is formed by applying the coating composition to a metal plate by an appropriate method and forming a film. As the coating method, known methods such as a roll coating method, a curtain coating method, a spraying method, a dipping method, an electrolytic treatment method and an air knife method can be adopted. The coating composition is applied on the metal plate or, when a layer other than the coating layer is formed, on the layer other than the coating layer. After applying the coating composition, the coating composition is dried at room temperature, dried by a heating device such as a hot-air stove, an electric furnace, an induction heating furnace, or baked, if necessary, to form a coating layer. It When the coating composition has energy ray curability, a coating layer is formed on the coating composition after coating by curing the coating composition by irradiation with energy rays such as infrared rays, ultraviolet rays and electron rays. May be. The drying temperature and the drying time of the coating composition are appropriately determined depending on the type of coating composition used, the required productivity, and the like. The coating layer may be a continuous film or a discontinuous film.

When the coating composition contains a silicate-based compound, the concentration of the silicate-based compound increases near the surface layer of the coating film of the coating composition in the process of curing and film formation of the coating composition, and the silicate-based compound is air A large number of hydrophilic groups (hydroxyl groups) are generated on the surface of the coating layer by being hydrolyzed by the water content. As a result, the hydrophilicity of the coating layer becomes high, so that the coating layer exhibits particularly high antifouling property.

The thickness of the coating layer is appropriately determined according to the type of coating composition, required performance, and the like. For example, when the coated metal sheet is used as a precoated metal sheet product (a product which is mechanically processed after coating), it is preferable to form a coating layer having a thickness of about 5 to 200 μm. When the coating is applied after the metal plate is mechanically processed, or after the metal plate after further processing is applied as a building material, the thickness of the coating layer should be thicker, for example, several mm. The thickness is preferable.

1. Preparation of Coating Compositions The coating compositions of Examples 1-14 and Comparative Examples 1-7 having the compositions shown in Table 1 were prepared. In addition, the polyester resin coating material in Table 1 is 50 mass% of polyester resin (Mitsui Chemicals, Inc. "Almatex P645"), 10 mass% of melamine resin curing agent (Mitsui Cytec, "Cymel 303") and 40 mass%. % Of titanium oxide (“CR-95” manufactured by Ishihara Sangyo Co., Ltd.), the fluororesin coating is 40% by weight of polyvinylidene fluoride resin (“Kynar 500” manufactured by Arkema Co., Ltd.) and 20% by weight. It is a coating material containing an acrylic resin (methyl methacrylate/ethyl acrylate weight ratio 70/30) and 20% by weight of titanium oxide (“CR-95” manufactured by Ishihara Sangyo Co., Ltd.). In addition, hydrotalcites are magnesium dehydrated aluminum hydroxide carbonate carbonate hydrate (Mg ₆ Al ₂ (OH) ₁₆ CO ₃ /4H ₂ O) (Kyowa Chemical Co., Ltd. 1000).

2. Preparation of Painted Metal Plate As a metal plate, a molten 55% aluminum-zinc plated steel plate (galvalume steel plate (registered trademark)) having a plate thickness of 0.3 mm and a plate width of 250 mm was prepared. After degreasing this metal plate, a coating type chromate treatment was applied.

Then, when forming a coating layer based on a polyester resin paint, first apply an epoxy resin-based primer ("P667S" manufactured by Nippon Paint Industrial Coatings Co., Ltd.) on a metal plate, and then reach the maximum temperature By heating at 200° C., an undercoat layer having a thickness of 4 μm was formed. The coating composition was applied onto this undercoat layer and heated and baked at a maximum attainable temperature of 220° C. for 30 seconds to form a coating layer having a thickness of 15 μm.

When forming a coating layer based on a fluororesin paint, first apply a modified epoxy resin-based primer ("Uniflon 600" manufactured by Nippon Paint Industrial Coatings Co., Ltd.) on a metal plate and then reach a maximum temperature of 215. By heating at 0° C., an undercoat layer having a thickness of 5 μm was formed. The coating composition was applied onto this undercoat layer and heated and baked at a maximum attainable temperature of 220° C. for 30 seconds to form a coating layer having a thickness of 15 μm.

When forming a coating layer containing hydrotalcites, first, a modified epoxy resin-based primer (“Uniflon 600” manufactured by Nippon Paint Industrial Coatings Co., Ltd.) is applied on a metal plate, and then the maximum temperature 215 is reached. By heating at 0° C., an undercoat layer having a thickness of 5 μm was formed. On this undercoat layer, the same fluororesin paint used for the preparation of the coating composition was applied and heated and baked at the maximum attainable temperature of 220° C. for 30 seconds to form an intermediate coat layer having a thickness of 15 μm. .. The coating composition was applied onto the intermediate coating layer, and the coating layer was formed by heating and baking at the maximum attainable temperature of 100° C. for 30 seconds.

3. Evaluation test 3-1. Processability The processability test was implemented about Examples 1-14 and Comparative Examples 4-6 which used the algae repellent.

Corresponding coated metal plates having a coating layer containing no algae control agent were prepared corresponding to the respective Examples and Comparative Examples to be tested.

The coated metal plates of each of the examples and comparative examples and the coated metal plate of the comparison target were subjected to T-bend bending in an atmosphere of 20°C. The minimum T number that does not cause cracks in the coating layer in each of the examples and comparative examples is compared with the minimum T number that does not cause cracks in the coating layer in the comparison target. The case where the number of T's increases by 1 is designated as B, and the case where the number of T's increases by 2 or more is designated as C.

3-2. Algal resistance test In each Example and Comparative Example, a test sample was obtained by cutting a coated metal plate into a size of 50 mm x 70 mm. The test sample was placed on a flat plate in a deep petri dish. The mixed dispersion of algae (3 ml) was suction filtered and then inoculated onto the test sample. At 24 hours after the inoculation, a 2% aqueous solution of inorganic salt containing the same amounts of nitrogen, phosphorus and potassium was sprayed on the surface of the test sample. Subsequently, for 8 weeks, the test sample was illuminated with a fluorescent lamp for 16 hours in an illuminance range of 700 to 1200 lux, and then the state where the fluorescent lamp was turned off was continued for 8 hours. Then, the test sample was visually observed. As a result, the case where no algae growth was observed on the test sample was A, the case where algae growth was observed in the area having an area ratio of less than 10% in the test sample coating layer was B, and the test sample coating layer was The case where the growth of algae was observed in the area having an area ratio of 10% or more was evaluated as C.

3-3. Weather resistance test For Examples 1 to 14 and Comparative Examples 4 to 6 using the algaecide, weather resistance in accordance with JIS Z9107, 6.2.2.3 (Sunshine carbon arc lamp type dew cycle accelerated weather resistance test) The test was conducted.

Prepare a coated metal plate of a comparison target having a coating layer containing no algae control agent, corresponding to each of the examples and comparative examples to be tested, and a coated metal plate of each example and comparative example, and a coating of the comparison target. The metal plate was treated for 500 hours under the following conditions.
・Number of sunshine carbon arc lamps: 1 (uses type I filter)
-Power supply voltage: 180-230V single-phase AC-Average discharge voltage and current: 50V (±2%), 60A (±2%)
・Relative humidity: (50±5)%
・The temperature indicated by the black panel thermometer: 63±3℃
-Water injection time: 120 minutes irradiation and injection for 120 minutes, 102 minutes irradiation-Water supply water pressure: 78 to 127 kPa
The color of the coating layer of the coated metal plate before and after the treatment was measured by CM-3700d manufactured by Konica Minolta, and the color difference of the coating layer in each of Examples and Comparative Examples and the color difference of the coating layer in Comparative Objects were derived.

As a result, the difference between the color difference of the coating layer in each of the examples and comparative examples and the color difference of the coating layer in the comparison target is 1 or less (a range in which no difference is visually observed in the degree of fading), 1 or more and less than 3 (range in which a slight difference in the degree of discoloration is visually observed) is B, and 3 or more (range in which a large difference in the degree of discoloration is visually observed) is evaluated as C. did.

3-4. Antifouling test The coated metal plates of each Example and Comparative Example were attached to an exposure mount and exposed outdoors for 3 months. The exposure mount has a simulated roof made of resin corrugated sheet, and has a structure in which raindrops drop from the corrugated sheet onto the coated metal sheet during rainfall. The water contact angle on the surface of the coated metal plate after the exposure was measured using a water contact angle meter (contact angle meter PG-X manufactured by Matsubo Corporation).

Claims (7)

A coated metal plate comprising a metal plate and a coating layer which covers the metal plate and which contains a pyrithione compound and does not contain a resin paint. The coated metal plate according to claim 1, wherein the pyrithione compound is in the range of 0.5 to 15 mass% with respect to the entire coating layer. The coated metal plate according to claim 1 or 2, wherein the pyrithione compound contains a pyrithione metal salt. The coated metal plate according to claim 3, wherein the pyrithione metal salt contains zinc pyrithione. The coated metal plate according to any one of claims 1 to 4, wherein the coating layer contains a silicon compound. The coated metal plate according to claim 5, wherein the silicon compound contains at least one of a silicate compound and a cured product thereof. The coated metal plate according to any one of claims 1 to 5, wherein the coating layer further contains hydrotalcites.