KR20160017030A - Pest-repellent clear-coated stainless steel sheet, and production method therefor - Google Patents

Abstract

This pest-resistant, clear-coated stainless steel sheet has a stainless steel sheet original plate and a clear coating film formed on at least one of the stainless steel sheet original plate, wherein the clear coating film has a thickness of 25 占 퐉 By mass, and 0.50 to 7.0 parts by mass of the insect repellent agent composed of the synthetic pyrethroid compound is contained in 100 parts by mass of the clear coat film excluding the insect repellent.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pest-resistant, clear-coated stainless steel sheet,

The present invention relates to a clear-coated stainless steel sheet having pest-resistant properties and a method for producing the same.

The present application claims priority based on Japanese Patent Application No. 2013-156462 filed on July 29, 2013, the contents of which are incorporated herein by reference.

A clear-coated stainless steel sheet in which a clear coating film is formed on the surface of a stainless steel sheet has an appearance with a high-quality appearance, which makes use of a beautiful metallic luster peculiar to stainless steel (see, for example, Patent Documents 1 and 2). Further, the clear-coated stainless steel sheet is superior in corrosion resistance and durability to a coated steel sheet based on a galvanized steel sheet or the like classified as ordinary steel or a composite material obtained by bonding a film material to ordinary steel. As a result, clear-coated stainless steel sheets are widely used for housings, interior materials, and marking materials of household electrical appliances.

By the way, most of the household electric appliances such as the refrigerator and the air conditioner generate heat in the apparatus. Since the heated household appliances are likely to become a hotbed of insects such as wheels, it is required that the material used for the living current has a pest-resistant property.

Generally, two types of insect repellent are known, namely, a contact avoiding type and a non-volatile escape type. The contact avoidance type is concentrated in the surface layer portion of the coating film and is localized, thereby exhibiting a repelling effect when it comes into direct contact with insects. Since the contact-avoidant insect repellent agent itself is not deteriorated, a long-term sustainable effect can be expected. On the other hand, when the contact-avoidant insect repellent agent is not localized in the surface layer portion of the coating film, the effect is lowered.

The volatile escape type is advantageous in that the insect itself is gradually evaporated so as not to approach the insect, and the range of avoiding the insect can be broadened. However, since the insecticide gradually disappears due to volatilization, have.

In the case of the household electric current, it is rare to reapply the paint or exchange the parts between the time of purchase and the time of disposal. Therefore, when the pest-resistant property is given to the living current, the contact-avoiding type which is easy to keep the effect is selected.

Patent Document 3 proposes a steel sheet on which a coated film containing a contact-repelling insect repellent is formed on the surface of a steel sheet.

However, the steel sheet described in Patent Document 3 is not a clear-coated stainless steel sheet, and the design property is insufficient. In addition, the coating film in Patent Document 3 has a low surface hardness and insufficient scratch resistance.

If a clear coating film surface of a clear-coated stainless steel sheet is scratched, designability is deteriorated. Thus, in a clear-coated stainless steel sheet, high scratch resistance, that is, high surface hardness is obtained.

Japanese Patent Application Laid-Open No. Hei 02-111865 Japanese Patent Laid-Open No. 2002-143764 Japanese Patent No. 4755837

A problem to be solved by the present invention is to provide a pest-resistant clear coated stainless steel sheet having a high pest resistance, a high surface hardness and a high decorative effect, and a method for producing the same.

The pest-resistant clear coated stainless steel sheet of the present invention comprises a stainless steel sheet original plate and a clear coating film formed on at least one surface of the stainless steel sheet original plate,

Wherein the clear coating film is a cured coating film having a thickness of 25 占 퐉 or less and the thermosetting resin is crosslinked by a crosslinking agent other than an amino resin,

0.5 to 7.0 parts by mass of the insect repellent agent composed of a synthetic pyrethroid compound is contained in an amount of 0.50 to 7.0 parts by mass based on 100 parts by mass of the clear coat film excluding the insect repellent.

In the pest-resistant clear coated stainless steel sheet of the present invention, it is preferable that the cross-linking agent is composed of a polyfunctional isocyanate compound having two or more isocyanate groups in one molecule.

A process for producing a pest-resistant clear coated stainless steel sheet according to the present invention comprises the steps of applying a clear paint on at least one surface of a stainless steel plate so that the film thickness after drying is 25 탆 or less and curing to form a clear coat Have,

A clear paint containing a thermosetting resin, a crosslinking agent other than an amino resin, a insect repellent agent made of a synthetic pyrrolidone compound, and a solvent is used as the clear paint,

The content of the insect repellent is 0.50 to 7.0 parts by mass based on 100 parts by mass of the solid content of the clear paint excluding the insect repellent.

In the method for producing a pest-resistant clear coating stainless steel sheet of the present invention, it is preferable that the cross-linking agent is composed of a polyfunctional isocyanate compound having two or more isocyanate groups in one molecule.

The pest-resistant clear coated stainless steel sheet of the present invention has high pest resistance, surface hardness and designability.

INDUSTRIAL APPLICABILITY The method for producing a pest-resistant clear coated stainless steel sheet of the present invention can easily produce a pest-resistant clear coated stainless steel sheet having high pest resistance, surface hardness and designability.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plan view showing a test cover used for evaluating pest repellency. Fig.
2 is a perspective view showing a test body used for evaluating the pest resistance.
3 is a plan view for explaining a method for evaluating pest resistance.

<Pest resistance clear coating stainless steel plate>

Hereinafter, one embodiment of the pest-resistant clear coated stainless steel sheet of the present invention will be described.

The pest-resistant clear coated stainless steel sheet of the present embodiment comprises a stainless steel sheet original plate and a clear coating film formed on at least one surface of the stainless steel sheet original plate.

(Stainless steel plate original plate)

As the stainless steel plate, a stainless steel plate may be used, in which a chemical conversion film is formed by chemical conversion treatment or a stainless steel plate itself not subjected to chemical conversion treatment.

[Chemical conversion film]

As the chemical conversion film, a coating film containing one or both of an aminosilane-based silane coupling agent and an epoxy silane-based silane coupling agent is preferable. If a chemical conversion film containing these silane coupling agents is provided between the stainless steel plate master plate and the clear coating film, it is possible to make the chromate free glass free from pollution, and also to improve the adhesion between the stainless steel plate original plate and the clear coating film.

Examples of the aminosilane coupling agent include N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltriethoxysilane, Ethoxy silane, and the like.

Examples of the epoxy silane coupling agent include 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, etc. .

The deposition amount of the chemical conversion film is preferably 2 to 50 mg / m 2. If the deposition amount of the chemical conversion film is less than 2 mg / m 2, the gloss and corrosion resistance tend to decrease. If the deposition amount exceeds 50 mg / m 2, blisters may be formed on the surface of the coating film after the boiling water test. The preferable upper limit of the adhesion amount of the chemical conversion film is 30 mg / m 2, and more preferably 10 mg / m 2.

The deposition amount of the chemical conversion film can be obtained by measuring the amount of SiO ₂ in the fluorescent X-ray analysis.

When forming the above-mentioned chemical conversion film, it is preferable to baking and dry the stainless steel sheet so that the surface temperature (PMT) of the stainless steel sheet becomes 60 to 140 占 폚.

(Clear Coating Film)

The clear coating film is a cured coating film in which the thermosetting resin is crosslinked by a crosslinking agent other than melamine resin. The clear coating film is usually formed as a single layer on the surface of the stainless steel plate original plate, but a plurality of clear coating films may be stacked.

The thermosetting resin is not particularly limited as long as it has surface hardness, transparency and adhesion to stainless steel, and examples thereof include an acrylic resin, a polyester resin, an epoxy resin, and a fluororesin. Since the clear-coated stainless steel sheet of this embodiment has a scratch resistance, an acrylic resin is preferable as the thermosetting resin from the viewpoint of easily obtaining a high surface hardness.

The acrylic resin in the present embodiment is a polymer obtained by polymerizing a non-crosslinkable acrylic monomer and a crosslinkable acrylic monomer.

Examples of the non-crosslinkable acrylic monomer include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, methyl methacrylate, ethyl methacrylate, Aliphatic or cyclic acrylates such as n-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, and lauryl methacrylate can be used.

Examples of the crosslinkable acrylic monomer include an acrylic acid alkyl ester or a methacrylic acid alkyl ester having a crosslinkable functional group such as a hydroxyl group, a carboxyl group and an alkoxysilane group.

The acrylic resin in the present embodiment may be copolymerized with an acrylic resin such as methyl vinyl ether, styrene such as styrene and? -Methyl styrene, acrylamide, acrylamide such as N-methylol acrylamide and diacetone acrylamide, Based monomer may be copolymerized with one or more kinds of other monomers.

The crosslinkable acrylic monomer, the non-crosslinkable acrylic monomer and other monomers may be used alone or in combination of two or more.

The acrylic resin has a crosslinkable functional group such as a hydroxyl group, a carboxyl group and an alkoxysilane group, but these crosslinkable functional groups may have two or more in one molecule.

The glass transition temperature of the acrylic resin is preferably 30 to 90 ° C. If the glass transition temperature is less than 30 占 폚, the surface hardness of the clear coating film obtained by the crosslinking reaction may be lowered. Further, since the coating film softens due to the heat generated when the coated steel sheet is processed by press working or the like, there may be a problem that the peeled coating film called galling adheres to the metal mold. On the other hand, when the glass transition temperature exceeds 90 캜, the leveling property of the clear coating tends to be lowered, and the beautiful appearance of the surface of the clear-coated stainless steel itself may be damaged. The glass transition temperature can be measured by, for example, differential thermal analysis.

The number average molecular weight of the acrylic resin is preferably from 3,000 to 50,000.

When the number average molecular weight is less than 3,000, the reactivity with the crosslinking agent is lowered, so that the crosslinked resin is not sufficiently reacted and the reacted resin may not be formed as a film. On the other hand, when the number average molecular weight exceeds 50,000, the resin solution can not be used because the solubility in a solvent is insufficient, and thus the resin can not be used as a resin for a paint.

Q152, Q152, Q154, Q186, Q193, Q174, Q171, Q612, Q177, Q182, Q517, Q202, Q203, Q627, Q152, Q161, Q161, Q162, 458, 748-5M, 749-17AE, 748-16AE (manufactured by Mitsui Chemicals, Inc.), hetaroid 2160X, 2400, 2401B, 2453, 2462A, 2467S, 2468, 2637, 2665, 2795, 2680, 3001, 3012X , 3083, 3083-70B, 3098L, 3204EB-1, 3509, 3368, 3375, 3379, 3387, 3704-2, 3534, 3546-3, 3511, 3624B, 3675, 3675B-57, 3901B, 3588, 3322A, 3458 A-817, A-837, A-848-RN, A-814, 57- A-879, A-859-B, 52-666-BA, 52-668-BA, WZU-773, A-829, 55-129, 49-394-IM, A-875-55, A- LR-257, LR-286, LR-1503, LR-257, LR-237, 1532, LR-1545, LR-1569, LR-1573 and LR-1589 (manufactured by Mitsubishi Rayon Co., Ltd.). These may be used singly or in combination of two or more.

Examples of the crosslinking agent include a polyfunctional isocyanate compound having at least two isocyanate groups in one molecule, and a polyfunctional epoxy compound having at least two epoxy groups in one molecule. Of these, polyfunctional isocyanate compounds are preferable in that pest-resistant properties are easily obtained. Particularly when the thermosetting resin is an acrylic resin, when a polyfunctional isocyanate compound is used as a crosslinking agent, desired performance (pest resistance, surface hardness, designability) tends to be obtained.

The polyfunctional isocyanate compound is not particularly limited as long as it is capable of crosslinking the thermosetting resin. Specific examples of the polyfunctional isocyanate compound include aromatic diisocyanates such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), meta xylylene diisocyanate (XDI) and naphthalene diisocyanate (NDI), hexamethylene diisocyanate (HDI), and alicyclic diisocyanates such as isophorone diisocyanate (IPDI) and cyclohexane diisocyanate.

The polyfunctional isocyanate compound may be a so-called block-type isocyanate in which the isocyanate group is blocked with a blocking agent in order to inhibit the reactivity under non-heating under the premise of thermal crosslinking.

In the block-type isocyanate, the higher the dissociation temperature of the block agent, the lower the surface hardness of the clear coating film. Therefore, the dissociation temperature of the blocking agent is preferably 130 ° C or lower.

As commercially available products of isocyanate, desmodules N75MPA / X, N3200, N3300, N3390EA, N3790BA, N3600, XP2679, XP2410, HT, N3400, XP2580, N3800, E3265SN / MPA, Z4470MPA / X, Z4470SN, Z4470BA, XP2565, NZ1, L75 (C), IL1351, IL1451, HLBA, E14, E15, E22, E23, E29, MT, RE, RFE, Sumidur E21-1, E21-2, SBU isocyanate (0620), M393 100A, TKA-100, P301-75E, 21S-75E, MFA-75B, MHG-80B, E402-80B, E405-70B, TSE-100, AE700-100 , TSA-100, TSS-100, TSE-100, AE700-100, A201H, TLA-100 (manufactured by Asahi Kasei Chemicals), Bernok DN-902S, DN-950, DN- L-55E, L-45E, 2067, 2030, 2031, 2050, 2071, 2074, 2232, 2233, 2255, 2257, DN-981, DN-990, DN-992 (manufactured by DIC Corporation) HX, HXR, HXLV, HK, HX-T, HL, and 2096 (manufactured by Nippon Polyurethane Industry Co., Ltd.), etc. These may be used singly or two or more of them may be used in combination.

As a commercial product of the block type isocyanate, desmodule BL1100, BL1265MPA / X, BL3175, BL3272MPA, BL3475BA / SN, VPLS2253, BL3575MPA / SN, BL4265SN, VPLS2078 / 1, BL5375 (manufactured by Sumika Bayer Urethane Co., D-500, D-550, DB-980K (DIC (manufactured by Asahi Kasei Chemicals Co., Ltd.), TP-B80E, Coronate AP-M, MS-50, 2503, 2515, 2507 and 2513 (manufactured by Nippon Polyurethane Industry Co., Ltd.). These may be used singly or in combination of two or more.

In the present embodiment, an amino resin is not used as a crosslinking agent for the following reasons.

The clear-coated stainless steel sheet is characterized by its beautiful design characteristics, and its surface appearance tends to be prone to scratches due to its high-gloss appearance. Therefore, if the surface hardness does not reach a certain level, designability is impaired by scratches formed at the time of use. Therefore, in a clear-coated stainless steel sheet, the surface hardness of the clear coating film is important.

In general, in order to improve the surface hardness of the coating film, an amino resin such as melamine resin may be used as a crosslinking agent. However, as a result of investigation by the present inventors, it has been found that when an amino resin is used as a crosslinking agent, it is difficult for the pest resistance to appear. This is presumably because when the amino resin is used as the crosslinking agent, the hardening reaction proceeds rapidly, and therefore, the insect repellent becomes hard to be concentrated on the surface and the proportion of the insect repellent agent embedded in the coating film increases. As a result, the use efficiency of the insect repellent contained in the clear coating film is lowered and the insect repellent property is considered to be insufficient.

Such a phenomenon in which insect pest resistance is not sufficiently exhibited occurs particularly when butylated melamine resin, in which the reaction between the amino resins is likely to proceed, or an urea resin having a high reaction rate, is used.

Further, even when a polyfunctional isocyanate compound and an amino resin are used together as a cross-linking agent, the curing reaction progresses rapidly, so that the pest resistance is not sufficiently exhibited.

The insect repellent agent contained in the clear coat film is composed of a synthetic pyrethroid compound.

As the synthetic pyrethroid compound, it is possible to use a compound represented by the following chemical name: S-alpha-cyano-3-phenoxybenzyl = (Z) - (1R, 3S) -2,2- 2-dimethyl-3- (2-methyl-1-propenyl) vinyl] cyclopropanecarboxylate, ) Cyclopropanecarboxylic acid 2-methyl-4-oxo-3- (2-propenyl) -2- cyclopenten- Methyl-3-oxo-1-propenyl) -2,2-dimethylcyclopropanecarboxylic acid 2-methyl- D-tetramethrin &lt; / RTI &gt; Chemical name: (1R) -2,2-dimethyl- (2-methyl-1-propenyl) cyclopropane &lt; / RTI &gt; (5-benzyl-3-pryl) methyl &lt; / RTI &gt; (2-methyl-1-propenyl) cyclopropanecarboxylic acid 5-propargyl-2-ylmethyl, phenothrin Chemical name: 2,2-dimethyl 3- (2-methyl-1-propenyl) cyclopropanecarboxylic acid m-phenoxybenzyl, permethrin «Chemical name: 3- (2,2-dichloroethenyl) -2,2-dimethylcyclopropane (2-methyl-1-propenyl) cyclopropanecarboxylic acid cyano (3-phenoxybenzyl) (6-chloro-1, 3-benzodioxol-5-yl) phenyl) methyl] 2- (2,2-dichlorovinyl) -2-methylpropyl 3-phenoxybenzyl ether, &quot; cyflutrin &quot; 3,3-dimethylcyclopropanecarboxylic acid? -Cyano-4-fluoro-3-phenoxybenzyl, tefluthrin «Chemical name: 2,3,5,6-tetrafluoro (Z) - (1RS, 3RS) -3- (2-chloro-3,3,3-trifluoro-1-propenyl) -2,2-dimethylcyclopropanecarboxylate (1RS, 2RS) -2- (Z) - (2-chloro-3,3,3-trifluoro-1-propenyl) - [(Z) -1-propenyl] cyclopropane-1? -Carboxylic acid-2, 3-dimethylcyclopropanecarboxylate, (1R, 3R) -2,2-dimethyl-3- (1-propenyl) cyclopropanecarboxylic acid 2, 3,6-tetrafluoro-4- (1R, 3S) -3- (2,2-dichlorovinyl) -2,2-dimethylcyclopropane &lt; (3R) -3 - [(E) -3-methoxy-2-methyl-3-oxo &lt; / RTI &gt; (S) -2-methyl-4-oxo-3 - [(Z) -piperazin- (2R) -2,2-dimethyl-3- (2-methyl-1-propenyl) cyclopropanecarboxylate (2-methyl-1-propen-1-yl) -1-cyclohexylcarbamate Propanecarboxylic acid 2-methyl-4-oxo-3- (2-propynyl) -2-cyclopenten- Propenyl) -1-cyclopropanecarboxylic acid [2,5-dioxo-3- (2-propynyl) imidazolidin-1-yl] methyl}.

S-alpha-cyano-3-phenoxybenzyl = (Z) - (1R, 2S) -thiophene was used as an insect repellent in view of higher pest resistance and high heat resistance and persistence of insect repellent effect. 3S) -2,2-dimethyl-3- [2- (2,2,2-trifluoro-1 -trifluoromethylethoxycarbonyl) vinyl] cyclopropanecarboxylate is preferable.

The content of the insect repellent in the clear coating film is preferably 0.50 to 7.0 parts by mass, more preferably 0.80 to 5.0 parts by mass, and most preferably 0.80 to 3.5 parts by mass based on 100 parts by mass of the clear coating film excluding the insect repellent.

If the content of the insect repellent is less than the above lower limit value, the insect repellent effect is not sufficiently exerted. On the other hand, if the content of the insect repellent exceeds the upper limit value, improvement of the insect repellent effect becomes a limiting point, and even if the content is increased, the cost becomes high, which is useless.

The clear coating film may contain a coloring pigment, an extender pigment, a brightening agent, a brightening agent (for example, an aluminum powder, a pearl pigment, a glass flake, etc.). The clear coating film may contain resin beads for the purpose of adjusting the gloss and appearance of the surface. The clear coating film may contain an antioxidant, a preservative, a lubricant, a conductive agent, an ultraviolet absorber, a light stabilizer, and the like.

However, the components included in the clear coating film are included in such a range that the clearability of the clear coating film is not impaired. When the clear coating film contains a coloring pigment, the content of the coloring pigment in the clear coating film is preferably 0.1 to 18.0 parts by mass, more preferably 0.1 to 10.0 parts by mass with respect to 100 parts by mass of the clear coating film excluding the insect repellent.

The surface hardness of the clear coating film is a pencil hardness measured according to the scratch hardness (pencil method) of JIS K5600-5-4 (corresponding International Standard: ISO / DIS15184, Paints and varnishes-Determination of film hardness by pencil test) Or more. If the surface hardness of the clear coat film is hardness less than H by pencil hardness, scratches tend to occur. When the clear coating film is scratched, the high designability inherent to the clear-coated stainless steel sheet is impaired.

The pencil hardness of the clear coating film is more preferably 2H or more.

Since the clear coating film in the present embodiment is cleared, the clear-coated stainless steel sheet of the present embodiment exhibits a design with a high-quality feeling utilizing the beautiful appearance of stainless steel as a substrate.

Here, &quot; clear &quot; means that the light transmittance in the visible light region is 30% or more. The light transmittance in the visible light region is a light transmittance measured in a wavelength range of 380 nm to 750 nm using a spectrophotometer.

When the light transmittance in the visible light region of the clear coating film is less than 30%, the visible light is slightly transmitted, but the stainless steel plate can hardly be seen visually. As a result, a design utilizing the beautiful appearance of the stainless steel can not be obtained.

The light transmittance of the clear coating film in the visible light region is preferably 40% or more, more preferably 50% or more. In the present embodiment, the upper limit of the light transmittance in the visible light region of the clear coating film is not particularly specified, but the light transmittance can be 100%, preferably 99.5%.

The clear coating film may be formed only on the surface of the stainless steel plate, or on both the front surface and the back surface.

The thickness of the clear coating film formed on the surface of the stainless steel plate original plate is 25 탆 or less, preferably 1 to 10 탆. If the thickness of the clear coating film formed on the surface of the stainless steel plate is less than 1 mu m, it is difficult to control the thickness of the film, and the content of the insect repellent agent in the coating film becomes small, so that the insect repellent property may not be sufficiently exhibited. If the thickness of the clear coating film formed on the surface of the stainless steel plate original plate exceeds 25 mu m, the coating cost tends to be increased and the surface hardness tends to be lowered. Further, the light transmittance of the visible light region is lowered, and the designability of the stainless steel may be impaired. When the colored pigment is contained in the clear coating film, the lowering of the designability due to the lowered light transmittance becomes more remarkable.

The thickness of the clear coating film on the back surface is not particularly limited, but may be 1 占 퐉 or more. It is not always necessary that the clear coating film on the back surface has pest resistance and visible light transmittance.

&Lt; Process for producing a stainless steel sheet having a pest-resistant,

The method for producing a pest-resistant clear coating stainless steel sheet according to the present embodiment has a step of coating a clear paint on at least one surface of a stainless steel plate and curing the clear paint to form a clear coating film.

The clear paint includes a thermosetting resin, a crosslinking agent other than an amino resin, a insect repellent made of a synthetic pyrroloid compound, and a solvent.

In the clear paint, the constituent ratio of the crosslinking agent other than the thermosetting resin and the amino resin is preferably 0.1 to 2.0 mol, such as isocyanate group in the crosslinking agent, relative to 1 mol of the total moles of the crosslinkable functional groups contained in the thermosetting resin, More preferably 0.1 to 1.0 mol. If the composition ratio of the cross-linking agent other than the amino resin to the thermosetting resin is less than the above lower limit value, the surface hardness may be lowered. If the above-mentioned upper limit value is exceeded, the pest resistance may be lowered.

The solvent to be contained in the clear paint is not particularly limited and includes, for example, hydrocarbons such as toluene, xylene, benzene, cyclohexane, hexane, alcohol compounds such as methanol, ethanol, propanol, and butanol, (Acetone, methyl ethyl ketone, methyl isobutyl ketone and the like) and other polar solvents (dimethyl formamide, dimethyl sulfoxide and the like), and they are appropriately selected .

The clear paint may contain a catalyst as a reaction promoter between the thermosetting resin and the crosslinking agent. Particularly, when a block type isocyanate is selected as a crosslinking agent, it is preferable to add a catalyst to the clear paint. When the catalyst is contained in the clear paint, the dissociation of the block agent is promoted, and the crosslinking reaction can be uniformly advanced throughout the coating film.

Examples of the catalyst include metal catalysts such as tin catalysts, and organic catalysts such as amine catalysts. However, this catalyst is not particularly limited.

The clear paint may contain a defoaming agent, a leveling agent, a rheology control agent, and an anti-settling agent in order to improve the workability at the time of coating.

The content of the insect repellent in the clear paint is 0.50 to 7.0 parts by mass, preferably 0.80 to 5.0 parts by mass, more preferably 0.80 to 3.5 parts by mass, relative to 100 parts by mass of the solid content of the clear paint except for the insect repellent, Mass part is more preferable. Here, the solid content of the clear paint is a clear coating film.

If the content of the insect repellent is less than the above lower limit value, the insect repellent effect is not sufficiently exerted. On the other hand, if the content of the insect repellent exceeds the upper limit value, improvement of the insect repellent effect becomes a limiting point, and even if the content is increased, the cost becomes high, which is useless.

The method of applying the clear paint is not particularly limited, and for example, spraying, roll coating, bar coating, curtain flow coating, electrostatic coating and the like can be employed.

The curing conditions after application of the clear paint are preferably heated so that the material maximum reaching temperature (PMT) is 190 to 250 ° C. If the maximum temperature of the material is less than 190 占 폚, the curing reaction does not sufficiently proceed to lower the surface hardness of the clear coating film, and the adhesion between the stainless steel sheet and the clear coating film may be deteriorated. On the other hand, if the material maximum reaching temperature exceeds 250 캜, not only the curing reaction is saturated, but also the clear coating film is yellowed to deteriorate the designability.

In addition, when the maximum temperature of the material exceeds 250 DEG C, the insect repellent agent is apt to be thermally decomposed and the insect repellent property may be lowered.

&Lt; Operation and effect of the present embodiment >

The clear coating film in the present embodiment is obtained by crosslinking the thermosetting resin with a crosslinking agent other than the amino resin, and the synthetic pyrethroid insect repellent, which is of a non-contact type, is liable to be unevenly distributed in the surface layer portion. Therefore, the pest resistance is excellent. In addition, the clear coating film in this embodiment has a surface hardness because the thermosetting resin has a crosslinked three-dimensional mesh structure. In addition, the clear coating film of the present embodiment has high scratch resistance because of its high surface hardness, and prevents deterioration of designability due to scratches. Therefore, the clear-coated stainless steel sheet of the present embodiment is excellent in designability.

<Examples>

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to the following examples.

(Examples 1 to 9 and Comparative Examples 1 to 8)

As the stainless steel plate, a stainless steel plate SUS430 / No.4 abrasive finishing material manufactured by Shinnitetsu Sumikin Stainless Co., Ltd. was used. On both surfaces of the stainless steel plate, a non-chemical treatment of a chromate-based solution (Nippon pakeorayijing whether or sikki manufactured producing pearl coating E-305), using a roll coater, a measurement of X-ray fluorescence SiO ₂ is from 2 to 10㎎ / ㎡ the Respectively. Subsequently, baking was carried out so that the surface arrival temperature (PMT) reached 100 占 폚, and the resultant was dried.

Subsequently, the clear coatings shown in Tables 1 and 2 were coated using a bar coater so that the film thickness at the time of drying was as shown in Tables 1 and 2. Thereafter, the mixture was heated so that the surface temperature PMT reached 225 ° C, and the acrylic resin was crosslinked by diisocyanate to form a coating film. Thus, a coated stainless steel sheet was obtained.

As the acrylic resin used, a resin having a number average molecular weight of 5,000, a glass transition temperature of 60 占 폚, and an OH value of 60 mgKOH / g was used. As the diisocyanate, an amine block HDI having an NCO value of 10% was used. As the amino resin, an imino type methylated melamine resin was used.

<Evaluation>

The obtained coated stainless steel sheet was measured or evaluated as follows in terms of pest resistance, visible light transmittance, pencil hardness of the coating film, adhesion of the coating film, and workability of the coating film. The results are shown in Tables 1 and 2.

(1) Pest resistance

Pest resistance was evaluated by the following method.

First, as shown in Fig. 1, on one side of a veneer 11 of a square of 70 mm in length and 70 mm in width, a rectangular square having one side of 5 mm and a length of 40 mm Body 12 was attached to fabricate a test cover 10. Subsequently, as shown in Fig. 2, the test cover 10 was attached to a test plate 20a made of a stamped stainless steel plate manufactured in each example, to produce a test piece 1. As shown in Fig. The test cover 10 was mounted on a stainless steel plate (a stainless steel plate SUS430 / No.4 polishing finish material made by Shin-Nittsu Sumikin Stainless Co., Ltd.) 20b used in each example to prepare a comparative test specimen 2 ).

As shown in Fig. 3, the test body 1 and the comparative test body 2 are provided inside the box 3, and the water 4 and the food 5 are placed between the test body 1 and the comparative test body 2 ). Then, 20 adults of the German wheel (Blattella germanica) were put into the box 3, and left for 24 hours. The test cover 1 of the test body 1 and the comparative test body 2 were removed and the number of German wheels existing inside the test body 1 and the number of German wheels existing in the inside of the comparative test body 2 I measured the number of wheels each. Based on this number, the pest avoidance rate was calculated by the following formula (1) and the degree of avoidance effect was evaluated.

Because the wheels are dark and narrow, they usually enter the gaps formed under the test cover, but if the plate under the test cover has pest repellency, the wheels are avoided. As a result, the higher the pest resistance of the painted stainless steel sheet in the test body, the easier it is for wheels to gather inside the comparative test body which does not have pest-resistant properties. Therefore, by comparing the number of German wheels existing inside the test body 1 with the number of German wheels existing inside the comparative test body 2, the pest resistance can be evaluated.

(1) [Number of German wheels present in the comparative specimen] / [Number of German wheels present in the specimen]) × 100 (1)

Pest resistance 80% or more: Pass, 90% or more is particularly good.

Pest Resistance Less than 80%: Fail

(2) Visible Light Transmittance (Evaluation of Clearness of Coating Film)

The transmittance of the visible light was evaluated by the following method. First, clear coatings shown in Tables 1 and 2 were applied to a glass plate having a thickness of 2 mm so as to have a thickness of 4 to 6 占 퐉 at the time of drying and cured to form a coating film. The coating film was measured for the transmittance curve in the visible light wavelength region, and the integral value of this curve was calculated.

Subsequently, the transmittance curve of the visible light wavelength region was likewise measured in the unpainted glass plate as the blank, and the integral value of this curve was calculated. Based on these numerical values, the transmittance in the visible light wavelength region was calculated by the following formulas (2) and (3), and the clearability of the coating film was evaluated.

The light transmittance was measured in a wavelength range of 380 nm to 750 nm using a spectrophotometer (V670 manufactured by Nihon Bunko Co., Ltd.).

Transmittance of 30% or more: Pass, 50% or more is particularly good.

Transmittance less than 30%: Fail

[Equation 1]

X: the integral value of the unpatterned glass plate

X ': Light transmittance (%) of unpainted glass plate

Y: The integral value of the coated glass sheet

Z: Light transmittance (%) of coating film

(3) Pencil hardness (surface hardness)

 The surface hardness of the coating film was measured in accordance with the scratch hardness (pencil method) according to JIS K5600-5-4 (corresponding International Standard: ISO / DIS15184, Paints and varnishes-Determination of film hardness by pencil test), a pencil scratching test pencil of Mitsubishi Nippies Co. Was evaluated by pencil hardness.

Hardness H or more: Pass, 2H or more is particularly excellent.

Hardness F or less: Fail

(4) Cohesion of coating film

The test was conducted according to JIS K5600-5-6 / Adhesiveness (crosscut method) (corresponding international standard: ISO2409, Paints and varnishes-Cross cut test) and evaluated according to the following criteria.

5: Peeling is not seen at all, including the intersection of the cuts. (Pass)

4: Very little peeling is seen at the intersection of the cut and the edge. (Passed)

3: Nearly 20% of the plaid pattern is peeled off from the intersecting part or edge of the cut. (Failed)

2: Large cut along the rim of the cut, and close to 50% of the plaid pattern is peeled off (fail)

1: The cut part is peeled off entirely. (Failed)

(5) Processability of coating film

As a test object, a rectangular stainless steel plate was prepared. The coated stainless steel sheet was sandwiched between two plates having the same thickness as the coated stainless steel sheet on one side with the center in the longitudinal direction as a boundary. Subsequently, the coated stainless steel sheet was folded 180 degrees at the center in the longitudinal direction as a bent portion, and the folded coated stainless steel sheet and the two sheets were superimposed and tightly tightened with a vise.

The enlarged machined portion was enlarged by a magnifying glass of 30 times and visually observed. The degree of the crack was evaluated by the following criteria.

5: Cracks are not visible at machining points. (Pass)

4: There are several cracks in the machining point. (Pass)

3: A small number of cracks can be visually confirmed at the machining point (fail)

2: It is possible to confirm a small crack as well as a large crack at the machining point. (Fail)

1: Many large cracks occurred at the machining point, and the coating film is rolled up. (Failed)

Examples 1 to 9, which contained 0.5 to 7 parts by mass of insect repellent in the inside of a clear coating film obtained by crosslinking an acrylic resin with diisocyanate, exhibited excellent pest resistance and surface hardness. In addition, the adhesion of the coating film and the workability of the coating film were excellent.

In Comparative Examples 1 and 2 in which the content of insect repellent in the clear coating film was less than 0.50 parts by mass, the pest resistance was low.

Comparative Examples 3 and 4 containing a large amount of a coloring pigment in the coating film could not be said to be clear-coated stainless steel sheets.

In Comparative Examples 5 and 6 using a melamine resin as a crosslinking agent, the pest resistance was low.

In Comparative Examples 7 and 8, in which the film thickness of the clear coat film exceeded 25 mu m, the surface hardness was low.

Claims (5)

A stainless steel sheet original plate and a clear coating film formed on at least one surface of the stainless steel sheet original plate,
Wherein the clear coating film is a cured coating film having a thickness of 25 占 퐉 or less and the thermosetting resin is crosslinked by a crosslinking agent other than an amino resin,
A pest-resistant, clear-coated stainless steel sheet containing 0.5 to 7.0 parts by mass of a insect repellent agent composed of a synthetic pyrethroid compound, based on 100 parts by mass of the clear coat film excluding the insect repellent. The method according to claim 1,
Wherein the cross-linking agent comprises a polyfunctional isocyanate compound having two or more isocyanate groups in one molecule. A step of forming a clear coating film on at least one surface of the stainless steel plate so that the coating film thickness after drying is 25 占 퐉 or less and curing,
A clear paint containing a thermosetting resin, a crosslinking agent other than an amino resin, a insect repellent agent made of a synthetic pyrrolidone compound, and a solvent is used as the clear paint,
Wherein the content of the insect repellent is 0.50 to 7.0 parts by mass based on 100 parts by mass of the solid content of the clear paint excluding the insect repellent. The method of claim 3,
Wherein the cross-linking agent comprises a polyfunctional isocyanate compound having two or more isocyanate groups in one molecule. The method according to claim 1,
Wherein the clear coating film contains 0.1 to 18.0 parts by mass of a coloring pigment relative to 100 parts by mass of the clear coating film excluding the insect repellent.

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