JP6557775B2 - Paint plate and manufacturing method thereof - Google Patents

Description

  The present invention relates to a coated plate. More specifically, the present invention relates to a coated plate having excellent finish, low gloss, high diffuse reflectance, and adhesion.

  Conventionally, there has been a demand for high light reflectivity for coated steel plates used for reflectors of lighting fixtures, but in particular, with the recent trend toward LED lighting, higher efficiency in lighting fixtures has attracted more attention. It has come to be.

For example, Reference 1 (Japanese Patent Application Laid-Open No. 2003-236981) discloses a coated steel sheet having a high reflectance. This coated steel sheet is provided with two or more coating films on at least one side through a ground treatment layer on a zinc-based plated steel sheet. The coating film contains 30 g / m ² or more of titanium dioxide white pigment per side. Further, the surface shape of the coating film has a waviness wavelength of 100 μm or more and 3,500 μm or less and a waviness height of 0.5 μm or more.

  Reference 2 (International Publication 2012/076172 pamphlet) discloses a pre-coated metal plate for a reflector. This pre-coated metal plate for reflector is a visible light reflective undercoating film having a film thickness of 3 to 30 μm containing a binder resin and titanium oxide, and a film thickness of 10 to 10 containing a binder resin and a titanium oxide containing a fluorine-based resin thereon. It has a visible light reflective topcoat of 40 μm. Moreover, the addition amount of the titanium oxide in the said visible light reflective undercoat film is 40-150 mass parts with respect to 100 mass parts of binder resin solid content. Moreover, the addition amount of the titanium oxide in the said visible light reflection topcoat film is 40-150 mass parts with respect to 100 mass parts of binder resin solid content.

  Further, Document 3 (Japanese Patent Laid-Open No. 2005-169857) discloses a coated metal plate having an undercoat coating film and a topcoating film. In this coated metal plate, at least one of the undercoat and the topcoat contains 0.5 to 10% by mass of thermosetting resin particles having an average particle diameter of 5 to 50 μm in addition to titania.

  In addition, Document 4 (Japanese Patent Laid-Open No. 2006-192660) discloses a coating material having a high diffuse reflectance. This coating material is a material having a coating layer on at least a part of the surface, and a high pigment concentration layer containing a white pigment of 150 parts or more and less than 1500 parts with respect to 100 parts of the binder in the coating layer. Have at least one layer.

  Further, Reference 5 (Japanese Patent Laid-Open No. 2007-290293) discloses a coated base material. This coated substrate has a coating layer on at least a part of the substrate surface, the coating layer is composed of at least two layers, the outermost layer has a film thickness of 20 μm or less, and a diffuse reflectance of 95. %, And a delustering agent is contained in the outermost layer.

  Further, Document 6 (Japanese Patent Laid-Open No. 2007-229630) discloses a white coated steel sheet having a top coat film thickness of more than 20 μm and a total coat film thickness of 30 μm or more. In this white coated steel sheet, it is disclosed that the top coat film contains colorless inorganic particles having an average particle diameter of 1 to 10 μm in addition to the white pigment, thereby eliminating or suppressing the occurrence of cracks in the top coat film. ing.

  However, the steel sheet having the coating film described in References 1 to 6 has devised titanium dioxide and a matting agent in order to obtain a high diffuse reflectance, but the finish, low gloss, high diffuse reflectance and It was not possible to obtain a coated plate with excellent adhesion.

  The problem to be solved by the present invention is to provide a coated plate excellent in finish, low gloss, high diffuse reflectance and adhesion.

  As a result of intensive studies, the present inventors have found that the problem can be achieved by a coated plate having a multilayer coating film comprising two layers of a specific primer layer and a specific top coating film layer on the substrate.

  The lighting fixture of 1 aspect which concerns on this invention is a coating board which has a multilayer coating film provided with two layers, a primer layer and the top coat film layer on this primer layer, on a board | substrate. The primer layer contains 80 to 250 parts by mass of a titanium oxide pigment based on a primer resin binder containing a polyester resin and a curing agent, and 100 parts by mass of the primer resin binder, and the thickness of the primer layer Is 10 to 20 μm. The top coat film layer comprises a top resin binder containing a polyester resin and a curing agent, and 100 to 250 parts by mass of a titanium oxide pigment and an organic polymer fine particle having an average particle size of 4 to 9 μm with respect to 100 parts by mass of the top coat resin binder. It contains 10 to 30 parts by mass, and the top coat layer thickness is 20 to 35 μm. The diffuse reflectance at a wavelength of 550 nm on the surface of the multilayer coating film including the two layers is 85% or more.

FIG. 1 is a sectional view showing an embodiment according to the present invention.

  As is apparent from FIG. 1, the present embodiment is a coated plate 10 having a multilayer coating film 4 composed of two layers of a specific primer layer 2 and a specific topcoat film layer 3 on a substrate 1, The surface of the multilayer coating film 4 composed of the two layers can obtain a diffuse reflectance of 85% or more at a light wavelength of 550 nm. According to this embodiment, it is possible to provide a coated plate that is excellent in finish, low glossiness, high diffuse reflectance, and adhesion. By applying the coating plate to a reflector of a lighting fixture (for example, LED), the light emitted from the light source can be efficiently reflected, so that even a light source with low power consumption can provide sufficient indoor illuminance. Details will be described below.

[substrate]
The board | substrate should just be a material conventionally used in order to form a building material, for example, is a metal plate, a wooden board, a glass plate, a plastic board etc. Among these, in view of strength, workability, etc., the substrate is preferably a metal plate. In this case, the painted plate is a painted metal plate. The metal plate is not particularly limited, but includes an alloy plate such as a steel plate, a stainless steel plate, an aluminum plate, a zinc plate, a copper plate, and an aluminum alloy plate. Further, a plating treatment is performed on these metal plates. Metal plate.

  Of these, examples of plating treatment on steel sheets include hot dip galvanized steel sheets, electrogalvanized steel sheets, galvannealed steel sheets, aluminum plated steel sheets, zinc alloy plated steel sheets (aluminum-zinc alloy plated steel sheets, aluminum-zinc-silicon). Alloy-plated steel sheets, aluminum-zinc-magnesium alloy-plated steel sheets, aluminum-zinc-magnesium-silicon alloy-plated steel sheets, zinc-magnesium alloy-plated steel sheets), tin-plated steel sheets, lead-plated steel sheets, chrome-plated steel sheets, etc. Can be mentioned. Moreover, what gave the chemical conversion treatment to these metal plates can also be used. As the chemical conversion treatment, generally known chemical conversion treatments such as coating-type chromate treatment, phosphate chromate treatment, electrolytic chromate treatment, zinc phosphate treatment, composite oxide film treatment, and recently developed chromate-free free of hexavalent chromium are included. Processing etc. can be used. Among these metal plates, an aluminum alloy plate or a plated steel plate is preferable in terms of finish and weight reduction.

[Primer layer]
The primer layer contains a primer resin binder containing a polyester resin and a curing agent, and a titanium oxide pigment. The primer layer is formed directly on the surface of the substrate.

[Polyester resin]
The polyester resin can be usually produced by an esterification reaction or a transesterification reaction with a polybasic acid component and a polyhydric alcohol component. As said polybasic acid component, an alicyclic polybasic acid component, an aliphatic polybasic acid component, an aromatic polybasic acid component, etc. can be used, for example.

  As the alicyclic polybasic acid component, generally, a compound having one or more alicyclic structures (mainly 4 to 6-membered rings) and two or more carboxyl groups in one molecule, an acid anhydride of the compound And an esterified product of the compound. Examples of the alicyclic polybasic acid component include 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, 3- Alicyclic polycarboxylic acids such as methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,3,5-cyclohexanetricarboxylic acid An anhydride of these alicyclic polyvalent carboxylic acids; a lower alkyl esterified product of these alicyclic polyvalent carboxylic acids, and the like. An alicyclic polybasic acid component can be used individually or in combination of 2 or more types.

  As the alicyclic polybasic acid component, in particular, 1,2-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic anhydride, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-cyclohexene- 1,2-dicarboxylic acid and 4-cyclohexene-1,2-dicarboxylic anhydride can be preferably used. Among the above, 1,2-cyclohexanedicarboxylic acid and 1,2-cyclohexanedicarboxylic anhydride can be particularly preferably used from the viewpoint of hydrolysis resistance.

  The aliphatic polybasic acid component is generally an aliphatic compound having two or more carboxyl groups in one molecule, an acid anhydride of the aliphatic compound, and an esterified product of the aliphatic compound, for example, Aliphatic polycarboxylic acids such as acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassic acid, octadecanedioic acid, citric acid; An anhydride of a polyvalent carboxylic acid; a lower alkyl esterified product of these aliphatic polyvalent carboxylic acids. An aliphatic polybasic acid component can be used individually or in combination of 2 or more types.

  As the aliphatic polybasic acid component, it is preferable to use a dicarboxylic acid having an alkylene chain having 4 to 18 carbon atoms. Examples of the dicarboxylic acid having an alkylene chain having 4 to 18 carbon atoms include adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassic acid, and octadecanedioic acid. Among them, adipic acid can be preferably used.

  The aromatic polybasic acid component is generally an aromatic compound having two or more carboxyl groups in one molecule, an acid anhydride of the aromatic compound and a lower alkyl esterified product of the aromatic compound, For example, aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, trimellitic acid, pyromellitic acid; anhydrides of these aromatic polycarboxylic acids And lower alkyl esterified products of these aromatic polycarboxylic acids. An aromatic polybasic acid component can be used individually or in combination of 2 or more types.

  As the polyhydric alcohol component, a polyhydric alcohol having two or more hydroxyl groups in one molecule can be preferably used. Examples of the polyhydric alcohol component (a2) include alicyclic diols, aliphatic diols, aromatic diols and trihydric or higher polyhydric alcohols.

  The alicyclic diol is generally a compound having one or more alicyclic structures (mainly 4- to 6-membered rings) and two hydroxyl groups in one molecule. Examples of the alicyclic diol include dihydric alcohols such as 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, hydrogenated bisphenol A, and hydrogenated bisphenol F; ε-caprolactone and the like in these dihydric alcohols. Examples include polylactone diol to which a lactone compound is added, and these can be used alone or in combination of two or more.

  The aliphatic diol is generally an aliphatic compound having two hydroxyl groups in one molecule. Examples of the aliphatic diol include ethylene glycol, propylene glycol, diethylene glycol, trimethylene glycol, tetraethylene glycol, triethylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 2,3 -Butanediol, 1,2-butanediol, 3-methyl-1,2-butanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-pentanediol, 1,5-pentanediol 1,4-pentanediol, 2,4-pentanediol, 2,3-dimethyltrimethylene glycol, tetramethylene glycol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3 -Pentanediol, 1,6-hexanediol, 1, -Hexanediol, 1,4-hexanediol, 2,5-hexanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, neopentyl glycol; polyethylene glycol, polypropylene glycol and poly Examples include polyether diol compounds such as butylene glycol, and these can be used alone or in combination of two or more.

  The aromatic diol is generally an aromatic compound having two hydroxyl groups in one molecule. Examples of the aromatic diol include ester diol compounds such as bis (hydroxyethyl) terephthalate; alkylene oxide adducts of bisphenol A and the like, and these can be used alone or in combination of two or more.

  Examples of the trihydric or higher polyhydric alcohol include glycerin, trimethylolethane, trimethylolpropane, diglycerin, triglycerin, 1,2,6-hexanetriol, pentaerythritol, dipentaerythritol, sorbitol, and mannitol. A trilactone or higher alcohol; a polylactone polyol compound obtained by adding a lactone compound such as ε-caprolactone to the trihydric or higher alcohol; tris (2-hydroxyethyl) isocyanurate, tris (2-hydroxypropyl) isocyanurate, And tris (hydroxyalkyl) isocyanurate such as tris (2-hydroxybutyl) isocyanurate. Of these, trimethylolpropane is particularly preferable.

  The production of the hydroxyl group-containing polyester resin used in the present embodiment is not particularly limited, and can be performed according to a usual method. For example, an acid component containing the polybasic acid component (a1) as an essential component and a polyhydric alcohol component are reacted in a nitrogen stream at 150 to 250 ° C. for 5 to 10 hours to perform an esterification reaction or a transesterification reaction. Can be manufactured.

  In the esterification reaction or transesterification reaction, the acid component and alcohol component may be added at once, or may be added in several portions. Moreover, after synthesize | combining a carboxyl group-containing polyester resin first, you may esterify some carboxyl groups in this carboxyl group-containing polyester resin using the said alcohol component. Furthermore, after first synthesizing the hydroxyl group-containing polyester resin, the acid anhydride may be reacted to half-esterify the hydroxyl group-containing polyester resin.

  In the esterification or transesterification reaction, a catalyst may be used to promote the reaction. As the catalyst, known catalysts such as dibutyltin oxide, antimony trioxide, zinc acetate, manganese acetate, cobalt acetate, calcium acetate, lead acetate, tetrabutyl titanate, and tetraisopropyl titanate can be used.

  Further, the hydroxyl group-containing polyester resin can be modified with a fatty acid, an oil, a fat, a monoepoxy compound, a monoalcohol compound, a polyisocyanate compound or the like during the preparation of the resin, or after the esterification reaction or the transesterification reaction.

  Examples of the fatty acid include coconut oil fatty acid, cottonseed oil fatty acid, hemp seed oil fatty acid, rice bran oil fatty acid, fish oil fatty acid, tall oil fatty acid, soybean oil fatty acid, linseed oil fatty acid, tung oil fatty acid, rapeseed oil fatty acid, castor oil fatty acid, dehydrated castor Examples include fatty acids such as oil fatty acids and safflower oil fatty acids; lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, and the like.

  Examples of the fat include coconut oil, cottonseed oil, hemp seed oil, rice bran oil, fish oil, tall oil, soybean oil, linseed oil, tung oil, rapeseed oil, castor oil, dehydrated castor oil, safflower oil and the like.

  Examples of the polyisocyanate compound used for the modification include aliphatic diisocyanate compounds such as lysine diisocyanate, hexamethylene diisocyanate, and trimethylhexane diisocyanate; hydrogenated xylylene diisocyanate, isophorone diisocyanate, methylcyclohexane-2,4-diisocyanate, methylcyclohexane. -Aliphatic diisocyanate compounds such as 2,6-diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), 1,3- (isocyanatomethyl) cyclohexane; aromatics such as tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate Diisocyanate compounds; organic poly- such as tri- or higher polyisocyanates such as lysine triisocyanate Isocyanate itself, or an adduct of each of these organic polyisocyanates with polyhydric alcohol, low molecular weight polyester resin or water, or a cyclized polymer of each of the above organic diisocyanates (for example, isocyanurate), biuret type addition And the like. These can be used alone or in combination of two or more.

  In addition, for the primer layer, if necessary, extender pigments, color pigments and pigment components such as chromate-based or chromate-free rust preventive pigments, curing catalysts, pigment dispersants, surface conditioners, matting agents, organic solvents In the range which does not impair the diffuse reflectance of 85% or more at a wavelength of 550 nm, a conventionally known material can be contained.

  The number average molecular weight of the polyester resin is preferably 2,000 to 30,000, particularly in the range of 3,000 to 25,000, from the viewpoint of the finish of the resulting coating film, coating film hardness, and workability. It is preferred to have a molecular weight.

  In addition, the number average molecular weight in this specification is the value which converted the number average molecular weight measured using the gel permeation chromatograph (GPC) on the basis of the molecular weight of standard polystyrene.

  Specifically, “HLC8120GPC” (trade name, manufactured by Tosoh Corporation) is used as a gel permeation chromatograph, and “TSKgel G-4000HXL”, “TSKgel G-3000HXL”, “TSKgel G-2500HXL” and Four “TSKgel G-2000HXL” (trade name, all manufactured by Tosoh Corporation) can be used, and measurement can be performed under conditions of mobile phase tetrahydrofuran, measurement temperature of 40 ° C., flow rate of 1 mL / min, and detector RI.

  The hydroxyl value of the polyester resin is preferably in the range of 10 to 200 mgKOH / g, particularly 60 to 185 mgKOH / g, from the viewpoint of the adhesion of the resulting coating film. The acid value of the polyester resin is 30 mgKOH / g or less, preferably 1 to 20 mgKOH / g from the viewpoint of finish.

[Curing agent]
The curing agent can be used without particular limitation as long as it can be cured by reacting with the hydroxyl group of the polyester resin by heating, and examples thereof include melamine resin, benzoguanamine resin, urea resin, and polyisocyanate compound. be able to.

  As said melamine resin, a part or all of methylol group of methylolation melamine is C1-C8 monohydric alcohol, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol , Partially etherified or fully etherified melamine resins etherified with i-butyl alcohol, 2-ethylbutanol, 2-ethylhexanol and the like.

  Examples of commercially available melamine resins include Cymel 202, Cymel 232, Cymel 235, Cymel 238, Cymel 254, Cymel 266, Cymel 267, Cymel 272, Cymel 285, Cymel 301, Cymel 303, Cymel 325, Cymel 327, and Cymel 350. , Cymel 370, Cymel 701, Cymel 703, Cymel 1141 (manufactured by Daicel Ornex Co., Ltd.), Uban 20SE60 (manufactured by Mitsui Chemicals, Inc.), and the like.

  Examples of the benzoguanamine resin include methylolated benzoguanamine resins obtained by reaction of benzoguanamine and aldehyde. Examples of the aldehyde include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde and the like. In addition, those obtained by etherifying this methylolated benzoguanamine resin with one or more alcohols are also included in the benzoguanamine resin. Examples of the alcohol used for etherification include monohydric alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, 2-ethylbutanol, and 2-ethylhexanol. . Among these, a benzoguanamine resin obtained by etherifying at least a part of the methylol group of the methylolated benzoguanamine resin with a monohydric alcohol having 1 to 4 carbon atoms is preferable.

  Specific examples of the benzoguanamine resin include, for example, My Coat 102, My Coat 105, My Coat 106 (all of which are manufactured by Mitsui Chemicals, Inc.), Nicarak SB-201, Nicarac SB-203, Nicarac SB-301, Nicarac SB. -303, Nicalac SB-401 (all of which are manufactured by Sanwa Chemical Co., Ltd.) and the like; Methyl etherified benzoguanamine resins such as Cymel 1123 (Daicel Ornex Co., Ltd.), and mixed etherified benzoguanamine resins of ethyl ether; Mixed ethers of methyl ether and butyl ether, such as My Coat 136 (Mitsui Chemicals), Nicalac SB-255, Nicalac SB-355, Nicalac BX-37, Nicalac BX-4000 (all of which are manufactured by Sanwa Chemical Co., Ltd.) Conversion Nzoguanamin resin; and the like butyl etherified benzoguanamine resins such as Mycoat 1128 (manufactured by Mitsui Chemicals, Inc.).

  The urea resin is obtained by a condensation reaction of urea and formaldehyde, and can be dissolved or dispersed in a solvent or water.

  Examples of the polyisocyanate compound include compounds having two or more isocyanate groups in one molecule, for example, aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and naphthalene diisocyanate; tetramethylene diisocyanate, hexamethylene diisocyanate, dimer Aliphatic diisocyanates such as acid diisocyanate and lysine diisocyanate; Alicyclic diisocyanates such as methylene bis (cyclohexyl isocyanate), isophorone diisocyanate, methylcyclohexane diisocyanate, cyclohexane diisocyanate and cyclopentane diisocyanate; Biuret type adducts of the polyisocyanate, isocyanuric ring type Addendum; this Et polyisocyanate and a low molecular weight or high molecular weight polyol compound (e.g., acrylic polyols, polyester polyols, polyether polyols, etc.) and there may be cited an isocyanate group excess obtained by reacting the free isocyanate group-containing prepolymer.

  Furthermore, as the polyisocyanate compound, the free isocyanate group of the polyisocyanate compound is a phenol compound, oxime compound, active methylene compound, lactam compound, alcohol compound, mercaptan compound, acid amide compound, imide compound, amine compound, imidazole. A blocked polyisocyanate compound blocked with a blocking agent such as a series compound, a urea series compound, a carbamic acid series compound, or an imine series compound can also be used.

  Moreover, a curing catalyst can be blended as necessary to accelerate the curing of the primer resin binder. Examples of the curing catalyst when the curing agent is an amino resin include strong acids and neutralized products of strong acids. Typical examples include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, diacid. Examples thereof include sulfonic acid compounds that are strong acids such as nonylnaphthalenedisulfonic acid, and amine neutralized products of these sulfonic acid compounds.

  As the curing catalyst when the curing agent is a blocked polyisocyanate compound, a curing catalyst that promotes dissociation of the blocking agent of the blocked polyisocyanate compound that is the curing agent, for example, tin octylate, dibutyltin di (2-ethyl) Hexanoate), dioctyltin di (2-ethylhexanoate), dibutyltin dilaurate, dibutyltin oxide, dioctyltin oxide, lead 2-ethylhexanoate and the like.

[Titanium oxide pigment]
The primer layer contains a titanium oxide pigment. The titanium oxide pigment is not particularly limited in its production method, presence / absence or type of surface treatment, but is preferably as highly concealed and high in whiteness as possible. Among them, a rutile type titanium oxide made by a chlorine method is preferable. What was surface-treated with alumina, silica, titania or the like is preferable.

  Commercially available products include, for example, Ti-Pure R706, Ti-Pure R960, Ti-Pure R902 + (above, manufactured by DuPont, trade name, titanium oxide pigment by chlorine method), Type CR CR-50, Type CR CR-60, Type P CR-95 (above, manufactured by Ishihara Sangyo Co., Ltd., trade name, titanium oxide pigment by chlorine method), CR-826 (trade name, manufactured by Tronox, trade name, titanium oxide pigment by chlorine method), and the like.

  The content of the titanium oxide pigment is within the range of 80 to 250 parts by mass, preferably 120 to 230 parts by mass, based on 100 parts by mass of the primer resin binder, and is suitable for finishing and high diffuse reflectance. ing. Moreover, it is suitable from the surface of finish property and a high diffuse reflectance that the film thickness of a primer layer exists in the range of 10-20 micrometers as a dry film thickness, Preferably it is 12-18 micrometers. In addition, the primer layer can be applied in two or more times when it cannot be applied at one time due to the occurrence of cracks.

  For the primer paint, a solvent, a leveling agent, a pigment dispersant, an anti-waxing agent, etc., which are usually used for a paint, can be appropriately used in order to improve the coating workability.

  As the coating method, curtain coating, roll coating, dip coating, spray coating, and the like are possible. However, when pre-coating is performed by coil coating or the like, the curtain coating method and the roll coating method are recommended because of its economical efficiency. When the roll coating method is applied, the top feed or bottom feed method with three rolls is recommended in order to achieve the best uniformity of the coating surface. So-called natural reverse paint or natural paint) may be used.

  The curing conditions (baking conditions) are usually about 15 seconds to 30 minutes at a material maximum temperature (PMT) of 120 to 260 ° C. In the field of pre-coating, which is applied by coil coating or the like, it is usually performed at a material maximum temperature of 160 to 260 ° C. for 15 to 90 seconds.

[Top coat layer]
The top coat layer is a coat layer with less gloss and is preferably a matte coat layer. When such a top coat layer is on the outermost surface of the coated plate, image reflection is reduced. The top coat layer contains a top resin binder containing a polyester resin and a curing agent, a titanium oxide pigment, and organic polymer fine particles having an average particle size of 4 to 9 μm. The top coat layer is directly formed on the surface of the primer layer.

[Coating resin binder]
As the polyester resin, the same polyester resin as described in the explanation column of the primer layer can be used. As the curing agent to be combined with the polyester resin, amino resins and blocked isocyanate compounds similar to those described in the explanation section of the primer layer are preferably used. Moreover, the hardening catalyst similar to what was described in the description column of the said primer layer can be mix | blended as needed in order to accelerate | stimulate hardening of top coat resin binder.

[Titanium oxide pigment]
The top coat layer contains a titanium oxide pigment. As the titanium oxide pigment, the same titanium oxide pigment as the primer layer can be used.

  The content of the titanium oxide pigment in the top coat layer is 100 to 250 parts by weight, preferably 140 to 190 parts by weight, with respect to 100 parts by weight of the top resin binder component. It is suitable from the point of balance of rate and adhesion.

[Organic polymer fine particles]
The top coat layer in this embodiment contains organic polymer fine particles for the purpose of low gloss and high diffuse reflectance. Examples of the organic polymer fine particles include urea resin-based organic polymer fine particles and acrylic resin-based organic polymer fine particles obtained by pulverizing a resin obtained by a condensation reaction of urea and an aldehyde component. Further, the organic polymer fine particles may be hollow fine particles.

  The organic polymer fine particles have an average particle diameter of 4 to 9 μm, preferably 5 to 8 μm. If the average particle diameter is less than 4 μm, high diffuse reflectance may not be obtained, while if the average particle diameter exceeds 9 μm, the finish may be impaired.

  The average particle diameter is a median diameter (d50) value of a volume-based particle size distribution measured by a laser diffraction scattering method using a Microtrac particle size distribution measuring device (trade name “MT3300”, manufactured by Nikkiso Co., Ltd.).

  Examples of the commercially available organic polymer fine particles include Pergo Pack M3 (trade name, manufactured by Lonza Japan), GR-800 (trade name, manufactured by Negami Kogyo Co., Ltd.), Techpolymer MBX-5, Techpolymer MBX-8 (and above). Sekisui Chemical Co., Ltd., trade name) and the like.

  The organic polymer fine particles blended in the top coat layer is suitable in the range of 10 to 30 parts by weight, preferably 11 to 20 parts by weight with respect to 100 parts by weight of the top coat resin binder.

  Further, the film thickness of the top coat layer is concealable and needs to be uniformly coated without unevenness, and the range of 20 to 35 μm, preferably 25 to 33 μm is suitable. In addition, the top coat layer may be coated in two or more times for the purpose of preventing the occurrence of cracks to form the top coat layer.

  In addition, for the top coat layer, a matting agent such as silica, a solvent, a leveling agent, a surface conditioner, an ultraviolet absorber, a light stabilizer, a pigment dispersant, an anti-waxing agent, which is usually used in paints as necessary. In the range which does not impair the diffuse reflectance of 85% or more at a wavelength of 550 nm, a conventionally known material can be contained.

  Curtain coating, roll coating, dip coating, and spray coating are possible as the coating method to obtain the top coat layer. However, when pre-coating is performed by coil coating, the curtain coating method and roll coating method are used because of its economic efficiency. Recommended. When the roll coating method is applied, the top feed or bottom feed method with three rolls is recommended in order to achieve the best uniformity of the coating surface. So-called natural reverse paint or natural paint) may be used.

  The curing condition (baking condition) of the top coating is usually performed in the range of 15 to 90 seconds at a material maximum temperature of 160 to 260 ° C. in the precoat coating field in which coating is performed by coil coating or the like.

[Multi-layer coating film]
The 60-degree specular gloss of the coated plate having a multilayer coating film composed of two layers of the primer layer and the top coating layer obtained as described above is in the range of 5 to 20%, preferably 6 to 15%. However, it is suitable for obtaining highly diffuse reflected light. The coated plate having a multilayer coating film composed of the two layers can obtain a diffuse reflectance of 85% or more, preferably 88% or more at a light wavelength of 550 nm.

  The diffuse reflection light is light reflected at an angle other than specular reflection (regular reflection), and incident light is reflected in various directions. Specular reflection (regular reflection) light is reflected from one direction. Light that is reflected in one direction.

  The highly diffusive reflective paint metal plate which is the paint plate of this embodiment is useful for providing the reflector of lighting fixtures, such as LED light.

  Moreover, the highly diffuse reflection coating metal plate which is a coating plate of embodiment is useful for providing various metal building materials (for example, wall material, ceiling material, roof material, etc.).

  In addition, the high diffuse reflection coated metal plate which is the painted plate of this embodiment is useful for providing a metal skin of a sandwich panel. That is, a sandwich panel is formed by providing a metal skin on both surfaces of a core material such as rock wool, but the metal skin provided on one side of the core material may be formed from the above highly diffuse reflective coating metal plate. The metal skin provided on both surfaces of the core material may be formed from the above highly diffuse reflective coating metal plate. The metal skin formed from the above highly diffuse reflective coating metal plate may form either the indoor or outdoor surface of the building.

  If the interior surface of the room is composed of the above highly diffuse reflective metal sheet, the high diffuse reflectance of the highly diffuse reflective metal sheet makes it easier for light to reach every corner of the room, creating dark areas in the room. In addition, it is possible to reduce the reflection of images of people and furniture on the interior surface of the room. As described above, the building material formed from the above highly diffuse reflective coating metal plate can easily provide a dimmed space in which a person can comfortably act.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. The present invention is not limited in any way by the following examples. Hereinafter, both “parts” and “%” are based on mass.

[Manufacture of primer paint]
Production Example 1 (Production Example of Primer Paint No. 1)
Byron GK-570 (Note 1) 85 parts (solid content), Cymel 232S (Note 2) 15 parts (solid content), Type CR-95 (Note 3) 130 parts, Cyloid 74 (Note 4) 1 part, Nacure 5225 (Note 5) Add 1 part, stir uniformly, mixed solvent of organic solvent (cyclohexanone / swazol 1500 (manufactured by Maruzen Petrochemical Co., Ltd., trade name, aromatic hydrocarbon organic solvent) = 40/60 (mass ratio) ) To adjust the viscosity to 120 seconds (Ford Cup # 4, 25 ° C.). 1 was obtained.

Production Example 2 (Production Example of Primer Paint No. 2)
Byron GK-570 (Note 1) 85 parts (solid content), Cymel 232S (Note 2) 15 parts (solid content), Taipei CR-95 (Note 3) 180 parts, Cyloid 74 (Note 4) 1 part, Nacure 5225 (Note 5) Add 1 part, stir uniformly, mixed solvent of organic solvent (cyclohexanone / swazol 1500 (manufactured by Maruzen Petrochemical Co., Ltd., trade name, aromatic hydrocarbon organic solvent) = 40/60 (mass ratio) ) To adjust the viscosity to 120 seconds (Ford Cup # 4, 25 ° C.). 2 was obtained.

Production Example 3 (Production Example of Primer Paint No. 3)
Byron GK-570 (Note 1) 85 parts (solid content), Cymel 232S (Note 2) 15 parts (solid content), Taipei CR-95 (Note 3) 220 parts, Cyloid 74 (Note 4) 1 part, Nacure 5225 (Note 5) Add 1 part, stir uniformly, mixed solvent of organic solvent (cyclohexanone / swazol 1500 (manufactured by Maruzen Petrochemical Co., Ltd., trade name, aromatic hydrocarbon organic solvent) = 40/60 (mass ratio) ) To adjust the viscosity to 120 seconds (Ford Cup # 4, 25 ° C.). 3 was obtained.

Production Example 4 (Production Example of Primer Paint No. 4)
Byron GK-570 (Note 1) 85 parts (solid content), Death Module BL-3175 (Note 6) 15 parts (solid content), Typek CR-95 (Note 3) 130 parts, Cyloid 74 (Note 4) 1 Part, Formate TK-1 (Note 7) 1 part was added and stirred uniformly. Organic solvent (cyclohexanone / swazol 1500 (manufactured by Maruzen Petrochemical Co., Ltd., trade name, aromatic hydrocarbon organic solvent) = 40/60 (Mixed solvent of (mass ratio)) is adjusted to a viscosity of 120 seconds (Ford Cup # 4, 25 ° C.). 4 was obtained.

[Manufacture of top coat]
Production Example 5 (Production of top coating No. 1)
Byron GK-140 (Note 8) 85 parts (solid content), Cymel 303 (Note 9) 15 parts (solid content), Taipei CR-95 (Note 3) 150 parts, Nacure 5225 (Note 5) 1 part, PERGOPAK M -3 (Note 10) 18 parts is added and stirred uniformly. Organic solvent (cyclohexanone / swazol 1500 (manufactured by Maruzen Petrochemical Co., Ltd., trade name, aromatic hydrocarbon organic solvent) = 40/60 (mass ratio) The mixed solvent was added and diluted, mixed, and the top coating No. of viscosity 140 seconds (Ford Cup # 4, 25 ° C.) was added. 1 was obtained.

Production Examples 6 to 28 (Production of top coating Nos. 2 to 24)
Except for the contents shown in Tables 1 to 4, the top coating No. 2-No. 24 was obtained.

[Example 1]
In accordance with the following steps 1 to 2, the coated plate (painted metal plate) No. 1 was obtained.

(Process 1)
Chromate-free chemical conversion treatment of 0.35 mm GL material (aluminum-zinc-silicon alloy-plated steel plate) was applied to primer paint No. with a roll-coater. 1 was coated to a dry film thickness of 16 μm and baked for 45 seconds at a maximum material temperature of 210 ° C.

(Process 2)
On top of the primer layer after step 1, the top coat No. 1 was coated to a dry film thickness of 25 μm, and baked for 55 seconds at a maximum material temperature of 220 ° C.

[Examples 2 to 14]
Except for the process contents shown in Tables 1 to 4, the coating plate No. 2-No. 14 was obtained.

[Example 15]
According to the following steps 1 to 2, the coated plate No. 15 was obtained.

(Process 1)
To a 0.35 mm stainless steel plate (SUS430) subjected to chromate-free chemical conversion treatment, primer paint No. 1 was coated to a dry film thickness of 16 μm and baked for 45 seconds at a maximum material temperature of 210 ° C.

(Process 2)
On top of the primer layer after step 1, the top coat No. 1 was coated to a dry film thickness of 25 μm, and baked for 55 seconds at a maximum material temperature of 220 ° C.

[Examples 16 to 20]
Except for the process contents shown in Table 3, the coating plate No. 16-No. 20 was obtained.

[Example 21]
According to the following steps 1 to 2, the coated plate No. 21 was obtained.

(Process 1)
A 0.35 mm aluminum alloy plate (3000 series) subjected to chromate-free chemical conversion treatment was subjected to primer coating No. with a roll-coater. 1 was coated to a dry film thickness of 16 μm and baked for 45 seconds at a maximum material temperature of 210 ° C.

(Process 2)
On top of the primer layer after step 1, the top coat No. 1 was coated to a dry film thickness of 25 μm, and baked for 55 seconds at a maximum material temperature of 220 ° C.

[Examples 22 to 26]
Except for the process contents shown in Table 4, the coating plate No. 22-No. 26 was obtained.

  As can be seen from Tables 1 to 4, on the substrate (metal plate), by the coated plate (painted metal plate) having a multilayer coating composed of two layers of the primer layer and the top coating layer on the primer layer, The diffuse reflectance at a light wavelength of 550 nm can be 85% or more.

  The above effects are that the titanium oxide pigment in the primer layer has a certain range of content, the film thickness of the primer layer is in a certain range, and the titanium oxide pigment in the overcoat layer has a specific range of content. It is considered that it can be obtained by including a certain amount of organic polymer fine particles having an average particle diameter of 4 to 9 μm and a film thickness of the top coat layer within a certain range.

[Comparative Examples 1 to 23]
Except for the process contents shown in Tables 5 to 7, the coating plate No. 27-No. 49 was obtained.

  As can be seen from Tables 5 to 7, the coating plate (Comparative Examples 1 to 8) in which the blending amount of the organic polymer fine particles in the coating film deviates from the upper limit or the lower limit, the organic polymer fine particles are not contained in the coating film, Coating plate (Comparative Examples 9 to 13) to be contained, Coating plate (Comparative Examples 14 to 15) in which the film thickness of the top coating film deviates from the lower limit or upper limit, and coating in which the content of titanium white in the upper coating film deviates from the lower limit or upper limit Even if the plate (Comparative Examples 16 to 17) and the material is an AL alloy plate or a stainless steel plate, the coating amount of the organic polymer fine particles is out of the upper limit or lower limit (Comparative Examples 18 to 21), and the primer layer has a lower limit or Although it was a coated plate (Comparative Examples 22 to 23) that deviated from the upper limit, none of the painted plates could satisfy all of finish, 60-degree specular gloss, diffuse reflectance, and adhesion.

  The details of (Note 1) to (Note 23) described in the specification in the table are as follows.

(Note 1) Byron GK-570: manufactured by Toyobo Co., Ltd., polyester resin, number average molecular weight 19,000, hydroxyl value 6 mgKOH / g
(Note 2) Cymel 232S: Daicel Ornex Co., Ltd., trade name, methyl / butyl mixed etherified melamine resin (Note 3) Taipei CR-95: Ishihara Sangyo Co., Ltd., trade name, Titanium White (Note 4) Cyloid 74: manufactured by Grace Co., Ltd., amorphous silica fine powder (Note 5) Nacure 5225: manufactured by King Industries, amine salt of dodecylbenzenesulfonic acid (Note 6) Desmodule BL-3175: manufactured by Sumika Bayer Urethane Co., Ltd. Trade name, isocyanurate-type trimer of methylmethylene ketone oxime blocked polyisocyanate of hexamethylene diisocyanate (Note 7) Formate TK-1: Osaka Shinyaku Co., Ltd., trade name, organotin catalyst (Note 8) Byron GK-140 : Toyobo Co., Ltd., hydroxyl value 10 mgKOH / g, number average Molecular weight 13,000, polyester resin (Note 9) Cymel 303: manufactured by Daicel Ornex Co., Ltd., trade name, methyl etherified melamine resin (Note 10) PERGOPAK M-3: trade name, manufactured by Lonza Japan, trade name, urea resin Organic polymer fine particles (organic resin fine particles), average particle size 6 μm
(Note 11) Love Color 230MD: manufactured by Dainichi Seika Co., Ltd., trade name, acrylic resin-based organic polymer fine particles, average particle size of 8 μm
(Note 12) GR-800: manufactured by Negami Kogyo Co., Ltd., trade name, acrylic resin organic polymer fine particles, average particle size 6 μm
(Note 13) Techpolymer MBX-5: manufactured by Sekisui Plastics Co., Ltd., acrylic resin-based organic polymer fine particles, average particle size 5 μm
(Note 14) Techpolymer MBX-8: manufactured by Sekisui Plastics Co., Ltd., acrylic resin-based organic polymer fine particles, average particle size 8 μm
(Note 15) GR-400: manufactured by Negami Kogyo Co., Ltd., trade name, acrylic resin-based organic polymer fine particles, average particle size 18 μm
(Note 16) AR-650M: manufactured by Toyobo Co., Ltd., trade name, acrylic resin organic polymer fine particles, average particle size 30 μm
(Note 17) Silicia 445: manufactured by Fuji Silysia, trade name, silica fine particles, average particle size 6 μm
(Note 18) Silicia 470: manufactured by Fuji Silysia Co., Ltd., trade name, silica fine particles, average particle size 14 μm
(Note 19) EMB-10: manufactured by Potters, trade name, glass beads, average particle size 10 μm
About the obtained multilayer coating film, the performance test was done with the following test method. The obtained results are also shown in Tables 1 and 2.

(Note 20) Finishability:
○ indicates that the paint surface is not abnormal or cloudy, such as repellency, dents, or bumps.
Δ indicates no coating surface abnormality such as repellency, dents, or irregularities, but clouding is observed on the coating surface.
In x, an abnormality in the paint surface such as repellency, dents, or irregularities is observed on the paint surface.

  (Note 21) 60 degree specular gloss: When the incident angle and the light receiving angle are 60 degrees according to the 60 degree specular gloss of JIS K 5600-4-7 (1999) The reflectance was measured and expressed as a percentage when the glossiness of the reference surface of the specular glossiness was taken as 100.

  (Note 22) Diffuse reflectance: CM-3700d manufactured by Minolta Co., Ltd. (using an integrating sphere, diffuse illumination 8 ° direction light reception) was used, and the reflectance at a wavelength of 550 nm was expressed as a percentage when the reference white plate was taken as 100. .

(Note 23) Adhesion: According to JIS K 5600-5-6 (1999) grid pattern-tape method, using a knife so as to reach the substrate surface of the coated plate, vertically at intervals of about 1 mm, 11 cuts are made parallel to each side to form a gobang, and a cellophane (registered trademark) adhesive tape is applied to the surface, and the gobang eye coating surface after the tape is peeled off is evaluated according to the following criteria. did.
A: No peeling of the coating film is observed.
In the case of ○, slight peeling is observed in a part of the coating film at the corner of the knife scratch.
Δ is 1 to 20 in which at least all of the 100 gobangs are peeled off.
X is 21 or more from which at least all of the 100 gobangs are peeled off.

  As is clear from the present embodiment described above, the painted plate (10) according to the first aspect is formed on the substrate (1), the substrate (1), the primer layer (2), and the primer layer (2). It is a coating board (10) which has a multilayer coating film (4) provided with two layers of top coat film layer (3). The primer layer (2) contains 80 to 250 parts by mass of a titanium oxide pigment based on a primer resin binder containing a polyester resin and a curing agent, and 100 parts by mass of the primer resin binder, and the primer layer ( The film thickness of 2) is 10 to 20 μm. The top coat layer (3) is an organic resin having a polyester resin and a curing agent containing a top coat resin binder and 100 parts by weight of the top coat resin binder, 100 to 250 parts by weight of a titanium oxide pigment, and an average particle diameter of 4 to 9 μm. It contains 10 to 30 parts by mass of polymer fine particles, and the film thickness of the top coat layer (3) is 20 to 35 μm. The diffuse reflectance at a light wavelength of 550 nm on the surface of the multilayer coating film (4) is 85% or more.

  In this case, the coated plate (10) of this embodiment is excellent in finish, low gloss, high diffuse reflectance, and adhesion.

  In the coated plate (10) according to the second aspect, in the first aspect, the curing agent of the primer resin binder is preferably at least one selected from an amino resin and a blocked polyisocyanate compound.

  In this case, the coated plate (10) of this embodiment has an effect that it has excellent adhesion.

  In the coated plate (10) according to the third aspect, in the first or second aspect, the curing agent of the top resin binder is at least selected from a hydroxyl group-containing polyester resin, an amino resin, and a blocked polyisocyanate compound. One type is preferable.

  In this case, the coated plate (10) of this embodiment has an effect that it is excellent in finish.

  In the coated plate (10) according to the fourth aspect, in the first to third aspects, the 60-degree specular gloss on the surface of the multilayer coating film (4) is preferably 5 to 20%.

  In this case, the coated plate (10) of this embodiment has an effect that it is excellent in diffuse reflectance.

  In the coated plate (10) according to the fifth aspect, in the first to fourth aspects, the substrate (1) is preferably one type selected from a plated steel plate, a stainless steel plate, and an aluminum alloy plate.

  In this case, the painted plate (10) of the present embodiment has an effect of achieving finish and weight reduction.

  The manufacturing method of the coating plate (10) which concerns on a 6th aspect is based on the primer resin binder containing a polyester resin and a hardening | curing agent on a board | substrate (1), and a titanium oxide pigment based on 100 mass parts of this primer resin binder. It has the process of applying and baking the primer coating containing 80-250 mass parts, and forming the primer layer (2) whose cured film thickness is 10-20 micrometers. Further, on the primer layer (2), 100 to 250 parts by mass of a titanium oxide pigment and 10 to 30 organic polymer fine particles having an average particle diameter of 4 to 9 μm with respect to 100 parts by mass of a top resin binder containing a polyester resin and a curing agent. It has the process of coating and baking the top coat containing a mass part, and forming a top coat film layer (3) with a cured film thickness of 20 to 35 μm. The diffuse reflectance at a light wavelength of 550 nm on the surface of the multilayer coating film (4) having two layers of the primer layer (2) and the top coating film layer (3) is 85% or more.

  In this case, the manufacturing method of the coated plate (10) of this embodiment has an effect that a coated plate (10) excellent in finish, low gloss, high diffuse reflectance, and adhesion can be obtained.

Claims (6)

A coated plate having a substrate and a multilayer coating film comprising two layers of a primer layer and a top coating film layer on the primer layer on the substrate,
The primer layer contains 80 to 250 parts by mass of a titanium oxide pigment based on a primer resin binder containing a polyester resin and a curing agent, and 100 parts by mass of the primer resin binder, and the thickness of the primer layer Is 10-20 μm,
The top coat film layer comprises a top resin binder containing a polyester resin and a curing agent, and 100 to 250 parts by mass of a titanium oxide pigment and an organic polymer fine particle having an average particle size of 4 to 9 μm with respect to 100 parts by mass of the top coat resin binder. 10 to 30 parts by mass, and the film thickness of the top coat layer is 20 to 35 μm,
A coated plate having a diffuse reflectance of 85% or more at a light wavelength of 550 nm on the surface of the multilayer coating film.   The coated plate according to claim 1, wherein the curing agent of the primer resin binder is at least one selected from an amino resin and a blocked polyisocyanate compound.   The coated plate according to claim 1 or 2, wherein the curing agent of the topcoat resin binder is at least one selected from a hydroxyl group-containing polyester resin, an amino resin, and a blocked polyisocyanate compound.   The coated plate according to any one of claims 1 to 3, wherein a 60-degree specular gloss on the surface of the multilayer coating film is 5 to 20%.   The said board | substrate is 1 type chosen from a plated steel plate, a stainless steel plate, and an aluminum alloy plate, The coating plate as described in any one of Claims 1-4. On the substrate, a primer resin binder containing a polyester resin and a curing agent, and a primer coating containing 80 to 250 parts by mass of a titanium oxide pigment based on 100 parts by mass of the primer resin binder are applied and baked to obtain a cured film thickness. Forming a 10 to 20 μm primer layer, and
On the primer layer, 100 to 250 parts by mass of a titanium oxide pigment and 10 to 30 parts by mass of organic polymer fine particles having an average particle diameter of 4 to 9 μm are included with respect to 100 parts by mass of a binder resin containing a polyester resin and a curing agent. Coating and baking a top coating material to form a top coating layer having a cured film thickness of 20 to 35 μm,
The manufacturing method of the coating board whose diffuse reflectance in the wavelength of 550 nm of light of the multilayer coating film surface provided with two layers of the said primer layer and the said top coat film layer is 85% or more.