JP2009297631A - Coating method of metallic feeling matte design coated metallic plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated metallic plate excellent in weatherability (light resistance, film thickness wear resistance), chemical resistance, coating film hardness, corrosion resistance, workability and designability (metallic matte coating film). <P>SOLUTION: A coating method of metallic feeling matte design coated metallic plate is carried out by forming a cured coating film (A1) having 1-10 μm dry film thickness from a primer coating material (A) on a metallic plate having a surface on which chemical conversion treatment can be applied, applies an intermediate coating material (B) containing 50-120 pts.wt. pigment component based on 100 pts.wt. of the total of a hydroxide group-containing resin and a crosslinking agent on the surface of the cured coating film (A1) and heating and curing to form a cured coating film (B1) having 5-20 μm dry film thickness and further applying a metallic feeling clear coating material (C) on the cured coating film (B1), heating and curing to form a cured coating film (C1) having 10-25 μm thickness. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a metallic gloss with excellent coating film hardness, weather resistance (light resistance, film thickness wear resistance), chemical resistance, coating film hardness, corrosion resistance, workability, and design (metallic matte coating film). The present invention relates to a method for painting a metal sheet with an eraser design coating.

  Recently, the field of application of pre-coated metal sheets has been expanding, and it has been applied to building interiors, shutter boxes, garages, and the like. Conventional polyvinyl chloride sol paints have excellent processability, acid resistance, water resistance, corrosion resistance, and weather resistance, but harmful substances may be generated during incineration of the coating film. It has been said. Here, in addition to being excellent in weather resistance and scratch resistance, for example, a matte metallic coating film may be required for interior parts of buildings, shutter boxes, garages, and the like.

Conventionally, a pre-coated metal plate having design properties such as weather resistance, workability and metallic feeling, and a pre-coated metal plate formed by sequentially forming an undercoat layer 2, an intermediate layer 3 and an overcoat layer 4 on a substrate 1, The intermediate layer 3 is disclosed as a melamine curable polyester resin clear paint blended with a designable powder material such as metal powder or organic colored beads, and the overcoat layer 4 is disclosed as a clear paint containing an ultraviolet absorber. Patent Document 1). However, the pre-coated metal plate of Patent Document 1 cannot be expected to have a long-term ultraviolet transmission preventing effect due to the elution of the UV absorber in the clear coating film of the top coat layer 4, and delamination or incidence due to deterioration of the intermediate coating. When the ultraviolet ray was reflected by the aluminum flakes of the intermediate coating layer, the clear layer as the upper layer deteriorated quickly, and the weather resistance (thickness resistance) was insufficient.
In addition, when the intermediate coating film contains a bright pigment as in the past, if the emphasis is on the design of the intermediate coating film, other pigment concentrations (colored pigments, extender pigments, aggregates) should be adjusted low. The coating may become soft due to the presence of scratches, and scratches that reach the metal substrate due to contact or impact during construction are likely to occur. The metal substrate is exposed and the corrosion resistance decreases. If the resin is hardened for the purpose of improvement, the processing performance is lowered, and it is impossible to achieve both scratch resistance and workability.

  In addition, it is a method of forming a coating film by applying a top coating base paint and a top clear coating through a primer cured coating, wherein the top clear coating is wet-on-wet on the top coloring base coating. A paint containing organic resin fine particles having an average particle diameter of 5 to 80 μm and a colored pigment in the top coat base paint, wherein the top clear paint is a paint containing glittering powder. A metal plate coating method is disclosed (Patent Document 2) which is formed by applying a clear paint that forms a shrink pattern with a glittering material on wet. However, although the colored base paint contains organic resin fine particles having an average particle size of 5 to 80 μm, the clear coating film that is directly affected by scratches and ultraviolet rays is significantly deteriorated, and further, it has a glossy texture. An erased metallic coating film could not be obtained. In the coating film by the top coating clear paint of patent document 2, the orientation of the glittering powder was not determined, and a coating film excellent in weather resistance (light resistance, film thickness wear resistance) and designability could not be obtained.

In addition, a primer coating having a glass transition temperature of 40 to 100 ° C. is formed on a metal plate whose surface may be subjected to chemical conversion treatment, and the primer coating (A) is formed on the primer coating (A). (B) An intermediate coating film having a glass transition temperature of 0 to 70 ° C. and a coating film elongation of 50 to 600% is formed, and (C) shrinkage is further formed on the intermediate coating film (B). The present invention relates to a coated metal sheet having a matte top coat film having a shrinkage pattern due to a paint and having a glass transition temperature of 20 to 85 ° C., and the matte top coat film contains organic resin fine particles. The inclusion is disclosed in [0052] to [0053] (Patent Document 3).
Patent Document 3 does not describe the formation of a coating film having a metallic design. Therefore, in order to obtain a coating film having a metallic design, for example, it is conceivable to apply a metallic coating film containing a glitter pigment and a coloring pigment on the intermediate coating film. However, in order to obtain the target color tone, (C) When a colored pigment is blended in the overcoat film, the color tone fluctuation is large due to deterioration of the glitter pigment (aluminum flakes) in the paint film due to acid rain or chemicals. . On the other hand, if a color pigment is not blended, a preferable color tone and designability (for example, warm color metallic design) may not be obtained.

Furthermore, the weather resistance (light resistance, film thickness wear resistance, acid rain resistance) was insufficient. Specifically, the multi-layer coating film (FIG. 1 shows a cross-sectional photograph of the uncoated coating film. FIG. 3 shows a model diagram of the orientation state of aluminum at this time) is weather resistance by a sunshine weatherometer. After the test, the coating film disappears, aluminum is exposed and deteriorates, and the coating film is discolored (a cross-sectional photograph of the coating film after the weather resistance test is shown in FIG. 2).
Patent Document 4 discloses a coating method in which an overcoat clear coating is applied wet-on-wet onto a primer-coated base coating film on a primer-cured coating film, and the overcoat clear coating has an average particle size of 5 to 5. It contains 80 μm organic resin particles, and [0058] discloses containing glitter powder as required. However, a coating film excellent in weather resistance (light resistance and film thickness wear resistance) could not be obtained only by including organic resin particles having an average particle diameter of 5 to 80 μm and glitter powder in the clear paint.

JP-A-8-318592 Japanese Patent Laid-Open No. 11-19582 JP 2000-204483 A Japanese Patent Laid-Open No. 11-90322

  The problems to be solved by the invention are metallic paints with excellent weather resistance (light resistance, film thickness wear resistance, acid rain resistance), chemical resistance, coating film hardness, corrosion resistance, workability, and design. The object is to find a method for coating a metal plate and to provide a metallic matte design coated metal plate that is excellent in the above-mentioned various performances.

  The present inventors bake and cure a three-layer coating film comprising a primer coating (A), an intermediate coating (B), and a metallic clear coating (C). The intermediate coating (B) contains a certain amount of the pigment component (b). The metallic clear paint (C) contains a certain amount of aluminum pigment (c3) having an average particle diameter of 10 to 22 μm and a certain amount of acrylic organic resin fine particles (c4) having an average particle diameter of 10 to 22 μm. Therefore, the aluminum pigment (c3) can be oriented as desired, weather resistance (light resistance, film thickness wear resistance, acid rain resistance), chemical resistance, coating film hardness, corrosion resistance, workability, and designability. The metallic matte design metal plate which was excellent in is led to obtain.

That is, the present invention
“1. A cured coating film (A1) having a dry film thickness of 1 to 10 μm is formed on the metal plate whose surface may be subjected to chemical conversion treatment, and the cured coating film (A1) is formed on the cured coating film (A1). In addition, with respect to a total solid content of 100 parts by mass of the hydroxyl group-containing resin and the crosslinking agent, an intermediate coating material (B) containing 50 to 120 parts by mass of the pigment component is applied and cured by heating to a dry film thickness of 5 to 20 μm. A cured coating film (B1) is formed, and a metallic clear paint (C) having the following characteristics is applied onto the cured coating film (B1) and heat-cured to obtain a cured coating film having a dry film thickness of 10 to 25 μm. (C1) Metallic matte design coating metal plate coating method characterized in that the metallic clear paint (C) contains a hydroxyl group-containing polyester resin (c1) and an amino resin (c2). C1: 50-90 parts by mass; c2: 1 1 to 10 parts by weight of an aluminum pigment (c3) having an average particle diameter of 10 to 22 μm and acrylic organic resin fine particles (c4 having an average particle diameter of 10 to 22 μm) based on 100 parts by weight of the total solid content of 0 to 50 parts by weight ) 0.1-10 parts by mass, and a paint film characterized in that a uniform crease pattern is generated on the coating film surface when the coating film is cured.
2. The metallic clear paint (C) further contains 0.1 to 15 parts by mass of silica fine powder having an average particle size of 10 μm or less with respect to 100 parts by mass of the total solid content of (c1) and (c2). The method for coating a metallic matte design coated metal sheet according to claim 1.
3. The coating film has a film thickness loss after irradiation of 2,000 hours of 3 μm or less in a sunshine carbon arc lamp type light resistance and weather resistance test stipulated in JIS B-7533. Metallic matte design painted metal plate described in 1. 4). The light transmittance of the cured coating film (C1) having a dry film thickness of 10 to 25 µm by the metallic clear paint (C) is an average of 10% or less in the visible light region having a wavelength of 400 nm to 700 nm. The method of coating the metallic matte design coated metal sheet according to the item. ".

  The present invention provides a metallic matte design coated metal plate with excellent weather resistance (light resistance, film thickness wear resistance, acid rain resistance), chemical resistance, coating film hardness, corrosion resistance, workability, and design properties. it can.

  The reason why the coated metal plate by the coating method of the present invention exhibits the desired performance is to first bake and cure the three-layer coating film of the primer coating (A), the intermediate coating (B) and the metallic clear coating (C). In addition, the intermediate coating material (B) can obtain a coating film excellent in coating film hardness and weather resistance by a specific range of pigment components.

Further, the metallic clear paint (C) contains aluminum pigment (c3) having an average particle diameter of 10 to 22 μm and a certain amount of acrylic organic resin fine particles (c4) having an average particle diameter of 10 to 22 μm. The pigment (c3) can have a desired orientation and can reflect ultraviolet rays, so that the coating is excellent in weather resistance (light resistance, film thickness wear resistance, acid rain resistance) without impairing design properties. .
The metallic clear coating (C1) by the metallic clear coating (C) is a clear coating containing an aluminum pigment (c3) to the extent that the intermediate coating can be recognized, and is an intermediate coating adjusted to a preferred color tone. In combination with the effect of the film, a favorable design (metallic matte coating) can be obtained.

  Furthermore, it is not necessary to include a colored pigment in the metallic clear paint (C), and the coating film over time as seen in the case of a combination of a conventional glittering pigment and a metallic coating film containing a coloring pigment. Possible reasons include less discoloration due to deterioration.

The present invention forms a cured coating film (A1) with a primer coating (A) on a metal plate whose surface may be subjected to chemical conversion treatment, and a hydroxyl group-containing resin is formed on the cured coating film (A1). An intermediate coating (B) containing 50 to 120 parts by mass of a pigment component is applied to a total solid content of 100 parts by mass with the cross-linking agent, and heat-cured to form a coating film. B1) Metallic matte design coating metal plate, characterized by forming a cured coating film (C1) by coating a specific metallic clear paint (C) and curing by heating. It is a metal plate.
Details will be described below.

[Metal coating]
Examples of the metal plate to be coated include iron, aluminum alloy, brass, copper plate, stainless steel plate, tin plate, galvanized steel plate, alloyed zinc (Zn-Al, Zn-Ni, Zn-Fe, etc.) plated steel plate, Metal plates such as aluminum-plated steel plates; surface-treated metal plates obtained by subjecting the surfaces of these metal plates to chemical conversion treatment such as phosphate treatment and chromate treatment. In addition to the above metal plate, a metal resin composite plate having a layer configuration of “metal plate / adhesive layer / resin layer / adhesive layer / metal plate” having a metal plate on the outermost layer on one or both sides is used. it can.

  In addition, a metal resin composite plate in which the surface of a non-metallic substance such as resin is coated with a metal layer by vapor deposition or the like can also be used as an object to be coated. Further, by melting the resin and sandwiching it between the metal resin composite plates, What is referred to as “plate / resin layer / metal plate” can also be used as an object to be coated.

  From the viewpoint of lightness and durability, a metal resin composite plate having a layer configuration of “metal plate / adhesive layer / resin layer / adhesive layer / metal plate” having a metal plate on the outermost layer on one or both sides is provided. Preferably, aluminum is more preferable as the metal plate in terms of corrosion resistance and workability.

[Primer paint (A)]
A primer coating film is formed on the metal article as necessary. Examples of the primer coating used for forming the primer coating on the metal plate to be coated include a primer coating (A) such as polyester resin and epoxy resin.

  For the coating film formation with the primer paint (A), the primer paint (A) is usually coated on a metal plate with a roll coater or the like so that the dry film thickness is 1 to 10 μm, preferably 2 to 8 μm. The cured coating film (A1) is formed by baking and drying at a maximum temperature (PMT) of 160 to 250 ° C. within a range of 15 to 180 seconds, particularly at a PMT of 180 to 230 ° C. within a range of 20 to 120 seconds.

[Intermediate paint (B)]
The intermediate coating (B) to be coated on the cured coating film (A1) contains 50 to 120 parts by mass of the pigment component with respect to 100 parts by mass of the solid content of the hydroxyl group-containing resin and the crosslinking agent. A cured coating film (B1) excellent in film hardness, chemical resistance and processability can be obtained.
Examples of the hydroxyl group-containing resin may include one or more of polyester resin, epoxy resin, acrylic resin, fluororesin and the like. Especially, a polyester resin can be used conveniently.

  Examples of the polyester resin include oil-free polyester resins, oil-modified alkyd resins, and modified products of these resins, such as urethane-modified polyester resins, urethane-modified alkyd resins, epoxy-modified polyester resins, and acrylic-modified polyester resins. The polyester resin has a number average molecular weight (Note 1) of 1,500 to 35,000, preferably 2,000 to 25,000, a glass transition temperature (Note 2) of 10 ° C. to 100 ° C., preferably 20 ° C. to 80 ° C. Those having a hydroxyl value of 1 to 100 mgKOH / g, preferably 5 to 80 mgKOH / g are suitable.

(Note 1) Number average molecular weight: measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.

(Note 2) Glass transition temperature: determined by differential scanning thermal analysis (DSC).
The oil-free polyester resin is an esterified product of a polybasic acid component and a polyhydric alcohol component. Examples of the polybasic acid component include one or more selected from phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic acid, fumaric acid, adipic acid, sebacic acid, maleic anhydride, and the like. Ester-forming derivatives such as dibasic acids and lower alkyl esterified products of these acids and acid anhydrides are mainly used, and monobasic acids such as benzoic acid, crotonic acid, and pt-butylbenzoic acid as necessary A tribasic or higher polybasic acid such as acid, trimellitic anhydride, methylcyclohexene carboxylic acid, pyromellitic anhydride is used in combination.

  Examples of the polyhydric alcohol component include bivalent compounds such as ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methylpentanediol, 1,4-hexanediol, and 1,6-hexanediol. Alcohol is mainly used, and a trihydric or higher polyhydric alcohol such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol can be used in combination as necessary.

  These polyhydric alcohols can be used alone or in admixture of two or more. The esterification or transesterification reaction of both components can be carried out by a method known per se. As the acid component, isophthalic acid, terephthalic acid, and lower alkyl esterified products of these acids are particularly preferable.

  In addition to the acid component and alcohol component of the oil-free polyester resin, the alkyd resin is obtained by reacting an oil fatty acid by a method known per se. Examples of the oil fatty acid include coconut oil fatty acid, soybean oil fatty acid, Examples thereof include linseed oil fatty acid, safflower oil fatty acid, tall oil fatty acid, dehydrated castor oil fatty acid, and kiri oil fatty acid. The oil length of the alkyd resin is preferably 30% or less, particularly about 5 to 20%.

As the urethane-modified polyester resin, the oil-free polyester resin or the low-molecular weight oil-free polyester resin obtained by reacting an acid component and an alcohol component used in the production of the oil-free polyester resin, a polyisocyanate compound and Examples thereof include those reacted by a method known per se.
Further, the urethane-modified alkyd resin is obtained by reacting a low molecular weight alkyd resin obtained by reacting each component used in the production of the alkyd resin or the alkyd resin with a polyisocyanate compound, a polyester resin or an alkyd resin. And a product obtained by reacting with a polyisocyanate compound at the time of production.

  Polyisocyanate compounds that can be used in the production of urethane-modified polyester resins and urethane-modified alkyd resins include hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4 ′. -Methylenebis (cyclohexyl isocyanate), 2,4,6-triisocyanatotoluene and the like. In general, as the urethane-modified resin, those having a modification degree such that the amount of the polyisocyanate compound forming the urethane-modified resin is 30% by mass or less with respect to the urethane-modified resin can be preferably used.

  As an epoxy-modified polyester resin, a polyester resin produced from each component used in the production of the polyester resin is used, a reaction product of a carboxyl group of the resin and an epoxy group-containing resin, a hydroxyl group in the polyester resin and an epoxy resin. The reaction product by reaction, such as addition of a polyester resin and an epoxy resin, condensation, grafting, etc., such as the product which couple | bonded the hydroxyl group in it through the polyisocyanate compound, can be mentioned. In general, the degree of modification in the epoxy-modified polyester resin is preferably such that the amount of the epoxy resin is 0.1 to 30% by mass with respect to the epoxy-modified polyester resin.

  As the acrylic-modified polyester resin, a polyester resin produced from each component used in the production of the polyester resin is used, and a group having reactivity with these groups on the carboxyl group or hydroxyl group of the resin, for example, carboxyl group, hydroxyl group or epoxy. Reaction products obtained by graft polymerization of a (meth) acrylic acid or (meth) acrylic acid ester to a polyester resin using a peroxide polymerization initiator are listed. be able to.

  In general, the degree of modification in the acrylic-modified polyester resin is preferably such that the amount of the acrylic resin is 0.1 to 50% by weight with respect to the acrylic-modified polyester resin. Among the polyester resins described above, among them, oil-free polyester resins and epoxy-modified polyester resins are preferable from the viewpoints of processability and corrosion resistance.

  Examples of the epoxy resin include bisphenol-type epoxy resins, novolac-type epoxy resins; and modified epoxy resins in which various modifiers are reacted with epoxy groups or hydroxyl groups in these epoxy resins. In the production of the modified epoxy resin, the modification time with the modifier is not particularly limited, and it may be modified in the middle of the epoxy resin production or in the final stage of the epoxy resin production.

  The bisphenol-type epoxy resin is, for example, a resin obtained by condensing epichlorohydrin and bisphenol to a high molecular weight in the presence of a catalyst such as an alkali catalyst, if necessary, epichlorohydrin and bisphenol, and if necessary, an alkali catalyst or the like. Any of resins obtained by condensing into a low molecular weight epoxy resin in the presence of a catalyst and polyaddition reaction of the low molecular weight epoxy resin and bisphenol may be used.

  Examples of the bisphenol include bis (4-hydroxyphenyl) methane [bisphenol F], 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane [bisphenol A], 2, 2-bis (4-hydroxyphenyl) butane [bisphenol B], bis (4-hydroxyphenyl) -1,1-isobutane, bis (4-hydroxy-tert-butyl-phenyl) -2,2-propane, p- (4-hydroxyphenyl) phenol, oxybis (4-hydroxyphenyl), sulfonylbis (4-hydroxyphenyl), 4,4′-dihydroxybenzophenone, bis (2-hydroxynaphthyl) methane, etc. Bisphenol A and bisphenol F are preferably used . The bisphenols can be used alone or as a mixture of two or more.

  Examples of commercially available products of bisphenol type epoxy resins include jER828, jER812, jER815, jER820, jER834, jER1001, jER1004, jER1007, jER1009, jER1010 (above, trade name, manufactured by Japan Epoxy Resin Co., Ltd.); Araldite AER6099 (Asahi Ciba) And Epomic R-309 (trade name, manufactured by Mitsui Chemicals, Inc.) and the like.

  Examples of the novolak-type epoxy resin that can be used as the coating film-forming resin include various novolaks such as a phenol novolak-type epoxy resin, a cresol novolak-type epoxy resin, and a phenol glyoxal-type epoxy resin having a large number of epoxy groups in the molecule. Type epoxy resin.

  As the modified epoxy resin, for example, an epoxy ester resin obtained by reacting a dry oil fatty acid with the bisphenol type epoxy resin or novolak type epoxy resin; and a polymerizable unsaturated monomer component containing acrylic acid or methacrylic acid is reacted. An epoxy acrylate resin; a polyester-modified epoxy resin reacted with a polyester resin; a urethane-modified epoxy resin reacted with an isocyanate compound; an amine compound in an epoxy group in the bisphenol-type epoxy resin, novolac-type epoxy resin, or various modified epoxy resins. And an amine-modified epoxy resin obtained by introducing an amino group or a quaternary ammonium salt.

Cross-linking agent:
The crosslinking agent can be used without particular limitation as long as it can be cured by reaction with a hydroxyl group-containing resin by heating, and melamine resin, benzoguanamine resin, urea resin, blocked polyisocyanate, etc. can be used. it can. Among these, in order to obtain the subject of this invention, it is preferable to use a melamine resin.

  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 Nippon Cytec Industries, Inc.), Uban 20SE60 (manufactured by Mitsui Cytec Co., Ltd.), and the like.

It is suitable from the point of coating-film hardness, workability, and corrosion resistance that it is 65-95 mass parts of the said hydroxyl-containing resin, Preferably it is 70-90 mass parts, 5-35 mass parts of crosslinking agents, Preferably it is 10-30 mass parts. It is.
In the intermediate coating material (B) used in the coating film forming method of the present invention, the pigment component is 50 to 120 parts by mass, preferably 60 to 100 parts by mass, based on 100 parts by mass in total of the solid content of the hydroxyl group-containing resin and the crosslinking agent. Part, more preferably 70 to 100 parts by mass. It is also preferable to be within the above-mentioned range in order to obtain a metallic matte design metal plate excellent in scratch resistance, corrosion resistance, and weather resistance.

  Examples of the pigment component include extender pigments such as clay, talc, barita and calcium carbonate; rust preventive pigments such as aluminum tripolyphosphate, zinc molybdate and vanadium pentoxide; white pigments such as titanium white and zinc white; cyanine blue Blue pigments such as Induslen blue; Green pigments such as cyanine green and patina; Organic red pigments such as azo and quinacridone; Red pigments such as Bengala and Bengala; Benzimidazolone, isoindolinone, and isoindoline And organic yellow pigments such as quinophthalone, yellow pigments such as titanium yellow, yellow lead, and yellow iron oxide; and colored pigments such as black pigments such as carbon black, graphite, and pine smoke.

  Furthermore, the intermediate coating (B) may contain a curing catalyst. The curing catalyst is blended as necessary to promote the reaction between the hydroxyl group-containing resin (A) and the crosslinking agent. When the crosslinking agent (B) is an amino resin, the sulfonic acid compound or sulfone is used. An amine neutralized product of an acid compound is preferably used.

  Representative examples of the sulfonic acid compound include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, and the like. The amine in the amine neutralized product of the sulfonic acid compound may be any of primary amine, secondary amine, and tertiary amine. Among these, the amine neutralized product of p-toluenesulfonic acid and / or the amine neutralized product of dodecylbenzenesulfonic acid is preferable from the viewpoints of coating stability, reaction promoting effect, and obtained coating film properties.

  When the cross-linking agent is a blocked polyisocyanate compound, curing catalysts include tin octylate, dibutyltin di (2-ethylhexanoate), dioctyltin di (2-ethylhexanote), dioctyltin diacetate. And organic metal compounds such as dibutyltin dilaurate, dibutyltin oxide, monobutyltin trioctate, lead 2-ethylhexanoate and zinc octylate. The curing catalyst is 0.1 to 5.0 parts by mass, preferably about 0.2 to 1.5 parts by mass with respect to the film thickness, with respect to 100 parts by mass of the total solid content of the hydroxyl group-containing resin and the crosslinking agent. Also suitable for sex.

  The intermediate coating (B) is applied by coating the intermediate coating (B) on the cured coating (A1) with a cured film thickness (B1) of 5 to 20 μm, preferably 10 by curtain coating or roll coating. It is painted to be ~ 18μm, and the maximum material temperature (PMT) is within the range of 15 to 180 seconds at 160 to 250 ° C, especially the range of 180 to 230 ° C and 20 to 120 seconds at the maximum material temperature (PMT). The cured coating film (B1) is formed by baking and drying under the above conditions.

  The color tone of the cured coating film (B1) thus obtained can be recognized through the cured coating film (C1) of the metallic clear paint (C) to be applied next, and a new matte metallic coating film can be obtained. Obtainable.

[Metallic clear paint (C)]
The average particle size is 1,500 to 25,000, and the average particle size is 100 parts by mass with respect to the total solid content of 50 to 90 parts by mass of the hydroxyl group-containing polyester resin (c1) and 10 to 50 parts by mass of the amino resin (c2). 1-10 parts by mass of 10-22 μm aluminum pigment (c3) and 0.1-10 parts by mass of acrylic organic resin fine particles (c4) having an average particle size of 10-22 μm.

Hydroxyl-containing polyester resin (c1):
Examples of the hydroxyl group-containing polyester resin (c1) include oil-free polyester resins, oil-modified alkyd resins, and modified products of these resins, such as urethane-modified polyester resins, urethane-modified alkyd resins, epoxy-modified polyester resins, and acrylic-modified polyester resins. Can be mentioned.

The oil-free polyester resin is an esterified product of a polybasic acid component and a polyhydric alcohol component. Examples of the polybasic acid component include one or more selected from phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic acid, fumaric acid, adipic acid, sebacic acid, maleic anhydride, and the like. Dibasic acids and lower alkyl esterified products of these acids are mainly used, and if necessary, monobasic acids such as benzoic acid, crotonic acid, pt-butylbenzoic acid, trimellitic anhydride, methylcyclohexentricarboxylic acid , Tribasic or higher polybasic acids such as pyromellitic anhydride are used in combination. Examples of the polyhydric alcohol component include bivalent compounds such as ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methylpentanediol, 1,4-hexanediol, and 1,6-hexanediol. Alcohol is mainly used, and a trihydric or higher polyhydric alcohol such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol can be used in combination as necessary. These polyhydric alcohols can be used alone or in admixture of two or more. The esterification or transesterification reaction of both components can be carried out by a method known per se. As the acid component, isophthalic acid, terephthalic acid, and lower alkyl esterified products of these acids are particularly preferable.
In addition to the acid component and alcohol component of the oil-free polyester resin, the alkyd resin is obtained by reacting an oil fatty acid by a method known per se. Examples of the oil fatty acid include coconut oil fatty acid, soybean oil fatty acid, Examples thereof include linseed oil fatty acid, safflower oil fatty acid, tall oil fatty acid, dehydrated castor oil fatty acid, and kiri oil fatty acid. The oil length of the alkyd resin is preferably 30% or less, particularly about 5 to 20%.

  As the urethane-modified polyester resin, the oil-free polyester resin or the low-molecular weight oil-free polyester resin obtained by reacting an acid component and an alcohol component used in the production of the oil-free polyester resin, a polyisocyanate compound and Examples thereof include those reacted by a method known per se. The urethane-modified alkyd resin is obtained by reacting the alkyd resin or a low molecular weight alkyd resin obtained by reacting each component used in the production of the alkyd resin with a polyisocyanate compound by a method known per se. Things are included. Polyisocyanate compounds that can be used in the production of urethane-modified polyester resins and urethane-modified alkyd resins include hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4 ′. -Methylenebis (cyclohexyl isocyanate), 2,4,6-triisocyanatotoluene and the like. In general, as the urethane-modified resin, those having a modification degree such that the amount of the polyisocyanate compound forming the urethane-modified resin is 30% by weight or less with respect to the urethane-modified resin can be preferably used.

  As an epoxy-modified polyester resin, a polyester resin produced from each component used in the production of the polyester resin is used, a reaction product of a carboxyl group of the resin and an epoxy group-containing resin, a hydroxyl group in the polyester resin and an epoxy resin. The reaction product by reaction, such as addition of a polyester resin and an epoxy resin, condensation, grafting, etc., such as the product which couple | bonded the hydroxyl group in it through the polyisocyanate compound, can be mentioned. In general, the degree of modification in the epoxy-modified polyester resin is preferably such that the amount of the epoxy resin is 0.1 to 30% by weight with respect to the epoxy-modified polyester resin.

  As the acrylic-modified polyester resin, a polyester resin produced from each component used in the production of the polyester resin is used, and a group having reactivity with these groups on the carboxyl group or hydroxyl group of the resin, for example, carboxyl group, hydroxyl group or epoxy. Reaction products obtained by graft polymerization of a (meth) acrylic acid or (meth) acrylic acid ester to a polyester resin using a peroxide polymerization initiator are listed. be able to. In general, the degree of modification in the acrylic-modified polyester resin is preferably such that the amount of the acrylic resin is 0.1 to 50% by weight with respect to the acrylic-modified polyester resin.

  Among the polyester resins described above, oil-free polyester resins are preferable. The hydroxyl group-containing polyester resin (c1) has a number average molecular weight of 1,500 to 35,000, preferably 3,000 to 25,000, a glass transition temperature (Tg point) of −30 to 100 ° C., preferably −20 to 60 ° C. ° C., hydroxyl value of 3 to 100 mg KOH / g, preferably 8 to 70 mg KOH / g. The glass transition temperature (Tg) is determined by differential thermal analysis (DTA), and the number average molecular weight is measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.

  As the metallic clear coating (C), an amino resin (c2) that reacts with the hydroxyl group-containing polyester resin (c1) to be crosslinked can be used. Specifically, the crosslinking agent used in the intermediate coating (B) is used. Can be used. The compounding amount of the amino resin (c2) is not particularly limited. Usually, in the total solid content of 100 parts by mass of the hydroxyl group-containing polyester resin (c1) and the amino resin (c2), the amino resin ( c2) is preferably in the range of 5 to 40 parts by mass.

Amino resin (c2):
Examples of the amino resin (c2) include melamine resin, benzoguanamine resin, and urea resin. In the present invention, it is preferable to use a melamine resin from the viewpoint of weather resistance and workability.

  Specifically, the melamine resin exemplified in the intermediate coating (B) can be used. The hydroxyl group-containing polyester resin (c1) is 65 to 95 parts by mass, preferably 70 to 90 parts by mass, and the amino resin (c2) 5 to 35 parts by mass, preferably 10 to 30 parts by mass. Furthermore, a curing catalyst or an amine compound can be blended as necessary.

  The curing catalyst is blended to promote the crosslinking reaction between the hydroxyl group-containing polyester resin (c1) and the amino resin (c2). For example, the curing catalyst described in the section of the intermediate coating (B) is used. A certain sulfonic acid compound or an amine neutralized product of a sulfonic acid compound can be mentioned.

  The amount of the curing catalyst is the amount of acid in the curing catalyst, for example, the amine neutralized product of the sulfonic acid compound, with respect to 100 parts by mass of the total of the hydroxyl group-containing polyester resin (c1) and amino resin (c2) Is 0.1 to 2.0 parts by mass, preferably 0.2 to 1.5 parts by mass in terms of the amount of sulfonic acid compound.

  The said amine compound is mix | blended in order to generate | occur | produce a shrinkage | contraction on the surface of an overcoat clear coating film, and the secondary or tertiary amine with a boiling point of 30-250 degreeC is used suitably. Specific examples of the amine compound include diethylamine, diisopropylamine, di-n-propylamine, diallylamine, diamylamine, di-n-butylamine, diisobutylamine, disec-butylamine, N-ethyl-1,2-dimethylpropylamine, N- Secondary amines such as methylhexylamine, di-n-octylamine, piperidine, 2-pipecoline, 3-pipecoline, 4-pipecoline, 2,4-, 2,6- or 3,5-lupetidine, 3-piperidinemethanol Triethylamine, tributylamine, triallylamine, N-methyldiallylamine, N-methylmorpholine, N, N, N ′, N′-tetramethyl-1,2-diaminoethane, N-methylpiperidine, pyridine, 4-ethylpyridine Tertiary amines such as N-methyl pipette One or more mixtures of such amines having secondary and tertiary amino groups, such as gin and the like. Of these, dialkylamines, particularly diisopropylamine, di-n-propylamine, di-n-butylamine, diisobulamine, and the like are preferred because of their low odor and beautiful uniform shrinkage.

  The compounding quantity of an amine compound is 0.1-10 mass parts with respect to a total of 100 mass parts of hydroxyl-containing polyester resin (c1) and amino resin (c2), Preferably it is 0.3-5 mass parts.

  Further, the metallic clear paint (C) is composed of a hydroxyl-containing polyester resin (c1) and an amino resin (c2), an aluminum pigment (c3) having an average particle size of 10 to 22 μm, and an acrylic organic material having an average particle size of 10 to 22 μm. Resin fine particles (c4) are contained.

Aluminum pigment (c3) having an average particle diameter of 10 to 22 μm:
The aluminum pigment (c3) having an average particle diameter of 10 to 22 μm (hereinafter, the aluminum pigment (c3) having an average particle diameter of 10 to 22 μm may be abbreviated as “aluminum pigment (c3)”) has a glittering radiance. For example, scaly glittering pigments such as aluminum flakes, aluminum oxide flakes, oxybismuth chloride flakes, nickel flakes and copper flakes are preferable.

  Among these, aluminum flakes are more preferable. For example, known non-leafing type aluminum flakes obtained by mechanically pulverizing metallic aluminum can be preferably used.

  The average particle diameter of the aluminum pigment (c3) is 10 to 22 μm, preferably 13 to 20 μm, and more preferably 15 to 18 μm. By using the aluminum pigment (c3) within this range, when blended together with the acrylic organic resin particles (c4) having an average particle diameter of 10 to 20 μm, the aluminum can be oriented as shown in FIG. A metallic matte design metal plate excellent in film thickness wear resistance, weather resistance and design properties can be obtained.

  As commercial products having such characteristics, aluminum paste HR-8801 (Asahi Kasei Metals Co., Ltd., trade name, average particle size 16 μm), aluminum paste HR-9000 (Asahi Kasei Metals Co., Ltd., trade name, average particle size 10 μm). ), Aluminum paste 88NL (Asahi Kasei Metals Co., Ltd., trade name, average particle size 13 μm), aluminum paste MC-666 (Asahi Kasei Metals Co., Ltd., trade name, average particle size 20 μm), aluminum paste EC-500B (Asahi Kasei Metals Co., Ltd.) , Trade name, average particle size 22 μm), Alpaste 7620NS (manufactured by Toyo Aluminum Co., Ltd., trade name, average particle size 19.4 μm), Alpaste 9420NS-A (manufactured by Toyo Aluminum Co., Ltd., trade name, average particle size 21 μm), Aluminum paste PCF7130 (made by Toyo Aluminum Co., Ltd., trade name, Average particle size 20 μm), aluminum paste PCF7620 (average particle size 20 μm, manufactured by Toyo Aluminum Co., Ltd.), aluminum paste 725N (Showa Aluminum Powder, average particle size 22 μm), Friend Color F500GR (Showa Aluminum Powder, average particle size 17 μm) ), Piochrome Orange L2800 (manufactured by BASF, average particle diameter of 18 μm), and the like.

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

The blending amount of the aluminum pigment (c3) is an amount within a range where the color of the intermediate coating film can be seen through the clear coating film, and in order to obtain good film thickness wear resistance, weather resistance and design properties, a hydroxyl group-containing polyester It is good to use in 1-10 mass parts with respect to a total of 100 mass parts of resin (c1) and a crosslinking agent, Preferably it is 1-8 mass parts, More preferably, it is 3-6 mass parts.
If the blending amount of the aluminum pigment (c3) is less than 1 part by mass, the film thickness wear resistance will be inferior, and the clear coating film after the weather resistance test will be diminished and the intermediate coating film will be exposed. Moreover, when the compounding quantity of an aluminum pigment (c3) exceeds 10 mass parts, it will become difficult to see the color tone of an intermediate coating film through a clear coating film, and the target design property of this application cannot be obtained.

Acrylic organic resin fine particles (c4) having an average particle diameter of 10 to 22 μm:
The metallic clear paint (C) comprises acrylic organic resin fine particles (c4) having an average particle diameter of 10 to 22 μm (hereinafter referred to as “acrylic organic resin fine particles (c4) having an average particle diameter of 10 to 22 μm”). 4), which may be abbreviated as “c4)”, the orientation of aluminum as shown in FIG. 4 can be obtained. The acrylic organic resin fine particles (c4) used in the metallic tone clear paint (C) adjust the orientation of the aluminum pigment (c3), and improve the film thickness wear resistance and weather resistance of the cured coating film (C1). Objective.

Specifically, Techpolymer MBX-12 (manufactured by Sekisui Plastics Co., Ltd., average particle size 12 μm, acrylic resin), Techpolymer MBX-15 (manufactured by Sekisui Plastics Kogyo Co., Ltd., average particle size 15 μm, acrylic resin) , Techpolymer MBX-20 (manufactured by Sekisui Plastics Co., Ltd., average particle size 20 μm, acrylic resin), techpolymer MB30X-20 (manufactured by Sekisui Plastics Co., Ltd., average particle size 20 μm, acrylic resin), techpolymer BM30X -20 (manufactured by Sekisui Plastics Co., Ltd., average particle size 20 μm, acrylic resin), Diasphere MPB-X10 (manufactured by KOLON, trade name, average particle size 10 μm, acrylic resin).
These acrylic organic resin fine particles (c4) have an average particle diameter of 10 to 22 μm, preferably 15 to 21 μm, more preferably 16 to 20 μm, as measured by a coal counter method. When blended with a 10-22 μm aluminum pigment (c3), the aluminum orientation as shown in FIG. 4 can be obtained, and a metallic matte design excellent in unprecedented film thickness wear resistance, weather resistance and design properties. A metal plate can be obtained.
The blending ratio of the acrylic organic resin fine particles (c4) is an acrylic organic resin having an average particle diameter of 10 to 22 μm with respect to a total solid content of 100 parts by mass of the hydroxyl group-containing polyester resin (c1) and the amino resin (c2). Fine particle (c4) is 0.1 to 10 parts by mass, preferably 1 to 8 parts by mass, more preferably 2 to 6 parts by mass. If the blending amount of the acrylic organic resin fine particles (c4) is less than 0.1 parts by mass, sufficient film thickness wear resistance may not be obtained, and the blending amount of the acrylic organic resin fine particles (c4) is 10 masses. If it exceeds the part, workability may be impaired.

  Furthermore, an organic solvent appropriately blended in the metallic clear paint (C) can be blended for improving paintability. For example, hydrocarbon solvents such as toluene, xylene, high-boiling petroleum hydrocarbons, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl Examples include ester solvents such as ether acetate, alcohol solvents such as methanol, ethanol and butanol, ether alcohol solvents such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether and diethylene glycol monobutyl ether, and water. It can be used alone or in admixture of two or more.

In addition, the metallic clear paint (C) may contain fine silica powder as necessary. Such silica fine powder has an average particle diameter of 10 μm or less, preferably an average particle diameter of 0.5 to 8 μm. By blending the silica fine powder, the corrosion resistance of the metallic coating film having a itchiness, in particular, a concave portion and a cut portion. Corrosion resistance can be improved.
The average particle diameter is a particle diameter in a state of being dispersed in the metallic clear paint (C), and is called a so-called secondary particle diameter. The silica fine powder includes those produced by either a wet method or a dry method, and may have a surface treated by coating or the like.

The silica fine powder is, for example, Aerosil 200, Aerosil 300, Aerosil 380, Aerosil TT600 (above, manufactured by Nippon Aerosil Co., Ltd.), Syloid 74, Syloid 83, Syloid 161, Syloid 162, Syloid 244, Syloid 308, Syloid 378 ( As described above, manufactured by Fuji Devison Chemical Co., Ltd., Mizukacil P-526, Mizukacil P-527, Mizukacil P-801, Mizukacil NP-8 (above, manufactured by Mizusawa Chemical Co., Ltd.), Nip Seal E200A, Nip Seal E220 (above, Nippon Silica Kogyo Co., Ltd.), Fine Seal E-50, Fine Seal E-70, Fine Seal T-32, Fine Seal X-37 (above, manufactured by Tokuyama Soda Co., Ltd.), Carplex # 67, Carplex # 80 (above, made by Shionogi Co., Ltd.), and the like.
The content of the silica fine powder having an average particle size of 10 μm or less in the metallic clear paint (C) is preferably a blending amount that does not impair the design for the purpose of stably forming a stagnation pattern or preventing ultraviolet transmission, 0.1 to 15 parts by mass, preferably 0.5 to 10 parts by mass, more preferably 1 to 8 parts by mass with respect to 100 parts by mass in total of the hydroxyl group-containing polyester resin (c1) and amino resin (c2). The range is good.

  In addition, to the metallic clear paint (C), either one or both of an ultraviolet absorber and a light stabilizer can be added to the coating composition as necessary in order to improve the weather resistance. Examples of such UV absorbers include benzotriazole, triazine, anilide, benzophenone, oxalate anilide, and cyanoacrylate. Commercially available products include “Tinuvin 1130”, “Tinuvin 400”, and “ASL-23”. "CYASORBUV-1164L" and "SANDUVOR3206" (above, manufactured by Ciba-Geigy).

  As the light stabilizer, a hindered amine system is suitable, and as commercially available products, “Tinuvin 123”, “Tinuvin 144” (above, manufactured by Ciba-Geigy), “Sanol LS-292” (above, made by Ciba-Geigy) ) Can be exemplified.

  The coating of the metallic clear paint (C) is preferably 10 to 25 μm in cured film thickness (C1) on the cured coating film (B1) by a curtain coating method or a roll coating method. Is coated at 12 to 20 μm, and the material reached maximum temperature (PMT) is within the range of 15 to 180 seconds at 160 to 250 ° C., particularly at the material reached maximum temperature (PMT) of 180 to 230 ° C. for 20 to 120 seconds. The cured coating film (C1) is formed by baking and drying under the conditions within the range of.

  According to the coating film forming method of the present invention, the orientation of aluminum shown in FIG. 4 can be achieved, and ultraviolet rays can be reflected more efficiently on the coating film surface layer. From this, deterioration of the coating film can be suppressed, and a metallic matte design metallic plate excellent in weather resistance (light resistance, film thickness wear resistance, acid rain resistance) unprecedented can be obtained. . The film thickness wear resistance is 3 μm or less, preferably 2 μm or less, more preferably 1.5 μm or less after 2,000 hours of irradiation with a sunshine weather meter as defined in JIS B-7511.

  Furthermore, the cured coating film (C1) by the metallic clear paint (C) has a light transmittance of 10% or less, preferably 8% or less, without containing an ultraviolet absorber in the metallic clear paint (C). More preferably, a multilayer coating film of 5% or less can be obtained. In addition, said light transmittance measures the light transmittance of 300-500 nm using Hitachi self-recording spectrophotometer U-3200 (Hitachi Ltd.), and the minimum value of a transmittance | permeability curve is light transmittance (%). ).

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited at all by the following examples, unless the summary is exceeded. Hereinafter, both “parts” and “%” are based on mass.

Production Example 1 Production of primer-coated metal sheet
KP color 8510 primer (epoxy resin primer for pre-coated steel plate) manufactured by Kansai Paint Co., Ltd. on a hot-dip galvanized steel plate with a thickness of 0.5 mm x 70 mm x 150 mm treated with zinc phosphate. Then, it was baked for 30 seconds so that the maximum material temperature reached 220 ° C. to obtain a primer-coated metal plate.

Production Example 2 Production of Polyester Resin Solution for Intermediate Coating Resin In a reactor equipped with a thermometer, stirrer, heating device and rectifying tower, 1079 parts isophthalic acid, 407 parts adipic acid, 466 parts neopentyl glycol, trimethylol 802 parts of propane was charged, the temperature was raised to 160 ° C., and the temperature was gradually raised from 160 ° C. to 230 ° C. over 3 hours.
Next, after continuing the reaction at 230 ° C. for 30 minutes, the rectifying column was replaced with a water separator, and 124 parts of xylene was added to the contents, and xylene was also added to the water separator to azeotrope water and xylene. The condensed water was removed and the reaction was allowed to proceed until the acid value reached 10 mgKOH / g, followed by cooling and addition of 855 parts of cyclohexanone to obtain a polyester resin solution having a solid content of 55%. The obtained resin had a hydroxyl value of 184 mgKOH / g, a number average molecular weight of 2,400, and a Tg point of -18 ° C.

Production Example 3 Production of 1 Polyester resin solution 75 parts (solid content) obtained in Production Example 2, Cymel 303 (Note 3) 25 parts (solid content), Neicure 5225 (Note 4) 0.6 parts (solid content), CR-95 (Note 5) 70 parts, Silicia 445 (Note 6) 10 parts, Carbon MA-100 (Note 7) 2 parts, TAROX HY-100 (Note 8) and Todacolor 130R (Note 9) are added to an organic solvent (cyclohexanone / swazol). No. 150040/60 mixed solvent) was added to dilute, and the intermediate coating material No. of viscosity 80 seconds (Ford Cup # 4, 25 ° C.) 1 was obtained.

  (Note 3) Cymel 303: Nippon Cytec Industries, Ltd., trade name, methyl etherified melamine resin.

  (Note 4) Necure 5225: manufactured by King Industries (USA), trade name, amine-neutralized solution of dodecylbenzenesulfonic acid.

  (Note 5) CR-95: Product name, titanium white, manufactured by Ishihara Sangyo Co., Ltd.

  (Note 6) Silicia 445: manufactured by Fuji Silysia Chemical Ltd., trade name, silica.

  (Note 7) Carbon MA-100: Product name, carbon black, manufactured by Mitsubishi Kasei Co., Ltd.

  (Note 8) TAROX HY-100: manufactured by Titanium Industry Co., Ltd., trade name, yellow iron oxide.

  (Note 9) Toda Color 130R: Toda Kogyo Co., Ltd., trade name, Bengala.

Production Examples 4 and 5, Comparative Production Examples 1 and 2 2-No. Production of No. 5 In the same manner as in Production Example 3 except that the contents shown in Table 1 were used, the intermediate coating material No. 2-No. 5 was obtained.

Production Example 6 Clear Paint No. 6 Production Example 1 Byron KS-1430V (Note 10) 80 parts (solid content), Cymel 303 (see Note 3) 20 parts (solid content), Aluminum paste HR-8801 (Note 11) 4 parts (solid content), Techpolymer MB30X-20 (Note 15) 10 parts (solid content), Neicure 5225 (Note 4) 0.3 parts (solid content), CYASORBUV-1164L (Note 21) 2 parts, Tinuvin 123 (Note 22) 1 Part and an organic solvent (a mixed solvent of cyclohexanone / swazol 150040/60) and a clear paint No. 1 having a viscosity of 110 seconds (Ford Cup # 4, 25 ° C.). 1 was obtained.

Production Examples 7 to 17 Clear paint No. 2-No. Production Example No. 12 Clear paint No. 12 was prepared in the same manner as in Production Example 6 except that the contents shown in Table 2 were used. 2-No. 12 was obtained.

  (Note 10) Byron KS-1430V: manufactured by Toyobo Co., Ltd., polyester resin, average molecular weight 12,000, hydroxyl value 11 mgKOH / g, glass transition point 1 ° C.

  (Note 11) Aluminum paste HR-8801: Asahi Kasei Metals Corporation, trade name, aluminum flake pigment, average particle size 16 μm.

  (Note 12) Aluminum paste MC-666: Asahi Kasei Metals Corporation, trade name, aluminum flake pigment, average particle size 20 μm.

  (Note 13) Alpaste 7620NS: manufactured by Toyo Aluminum Co., Ltd., trade name, aluminum flake pigment, average particle diameter 19.4 μm.

  (Note 14) Aluminum paste MR-9000 (Asahi Kasei Metals Corporation, trade name, aluminum flake pigment, average particle size 10 μm.

  (Note 15) Techpolymer MB30X-20: Sekisui Plastics Co., Ltd., acrylic resin fine particles, average particle size 20 μm.

  (Note 16) Techpolymer MBX-12: Sekisui Plastics Co., Ltd., acrylic resin fine particles, average particle size 12 μm.

  (Note 17) Techpolymer MBX-15: Sekisui Plastics Co., Ltd., acrylic resin fine particles, average particle size of 15 μm.

  (Note 18) Techpolymer MBX-20: manufactured by Sekisui Plastics Co., Ltd., trade name, acrylic resin fine particles, average particle diameter 20 μm.

  (Note 19) Diasphere MPB-X10: manufactured by KOLON, trade name, acrylic resin fine particles, average particle size 10 μm.

  (Note 20) Thyroid 161W: manufactured by GRACE GMBH, trade name, organically treated silica powder, oil absorption 170 ml / 100 g.

  (Note 21) CYASORBUV-1164L: trade name, ultraviolet absorber, manufactured by Ciba Geigy Corporation.

  (Note 22) Tinuvin 123: Product name, light stability, manufactured by Ciba Specialty Chemicals.

Comparative Production Example 3 Clear Paint No. Production Example 13 13 Byron KS-1430V (Note 10) 80 parts (solid content), Cymel 303 (see Note 3) 20 parts (solid content), Aluminum paste MR-8801 (Note 11) 0.5 part (solid content) ), 10 parts (solid content) of techpolymer MBX-30 (note 27), 0.3 part (solid content) of Neicure 5225 (note 4), 6 parts of syloid 161W (note 20), CYASORBUV-1164L (note) 21) 2 parts and 1 part of Tinuvin 123 (Note 22) are mixed, diluted with an organic solvent (mixed solvent of cyclohexanone / swazol 150040/60), and a clear paint having a viscosity of 110 seconds (Ford Cup # 4, 25 ° C.) No. 13 was obtained.

Comparative Production Examples 4 to 17 Clear Paint No. 14-No. Production Example No. 25 Clear paint No. 25 was prepared in the same manner as Comparative Production Example 3 except that the contents of Table 3 were used. 14-No. 25 was obtained.

  (Note 23) Aluminum paste MF-20: Asahi Kasei Metals Corporation, trade name, aluminum flake pigment, average particle size 25 μm.

  (Note 24) Aluminum paste CR-9800RM: Asahi Kasei Metals Co., Ltd., trade name, aluminum flake pigment, average particle size 8 μm.

  (Note 25) Alpaste 7220NS: manufactured by Toyo Aluminum Co., Ltd., trade name, aluminum flake pigment, average particle size 25 μm.

  (Note 26) Alpaste 7410NS: manufactured by Toyo Aluminum Co., Ltd., trade name, aluminum flake pigment, average particle size 28 μm.

  (Note 27) Techpolymer MBX-30: Sekisui Plastics Co., Ltd., acrylic resin fine particles, average particle size 30 μm.

  (Note 28) Techpolymer MBX-50: manufactured by Sekisui Plastics Co., Ltd., acrylic resin fine particles, average particle size 50 μm.

(Note 29) Techpolymer MB30X-5: manufactured by Sekisui Plastics Co., Ltd., acrylic resin fine particles, average particle size 5 μm.
(Note 30) Techpolymer MBXR-8N: Sekisui Plastics Kogyo Co., Ltd., acrylic resin fine particle average particle diameter of 8 μm.

  (Note 31) Aflon prepant 150J: manufactured by Asahi Glass Co., Ltd., polytetrafluoroethylene, average particle size 9 μm.

Example 1
On the “primer-coated metal plate” obtained in Production Example 1, the intermediate coating No. obtained in Production Example 3 was applied. 1 was coated with a roll coater so as to have a dry film thickness of 20 μm, and baked for 60 seconds at a maximum material reaching temperature of 190 ° C. to obtain a cured coating film.
Next, on the cured coating film, a clear paint No. No. 1 was coated with a roll coater to a dry film thickness of 15 μm and baked for 60 seconds at a maximum material reaching temperature of 230 ° C. 1 was obtained.

Examples 2-14
A multilayer coating film No. 1 was prepared in the same manner as in Example 1 except that the coating contents and heat curing conditions in Table 4 were used. 2-No. 14 was obtained. In addition, the test is performed according to the following test conditions, and the results are shown.

Comparative Examples 1-13
A multilayer coating film No. 1 was prepared in the same manner as in Example 1 except that the coating content and heat curing conditions in Table 5 were used. 15-No. 29 was obtained. In addition, the test is performed according to the following test conditions, and the results are shown.

(Note 32) Coating film appearance: The coating film appearance was observed with the naked eye and evaluated according to the following criteria.
In は, a dense and uniform shrinkage pattern occurs on the paint surface, and no paint surface abnormality such as repellency, dents, or cloudiness is observed.
In the case of ◯, a shrinkage pattern is generated on the paint surface, and no paint surface abnormality such as repellency, dents, or cloudiness is observed, but the denseness or uniformity of the shrinkage pattern is slightly inferior to the above-mentioned ◎.
For Δ, no paint surface abnormality such as repelling, dents, or cloudiness is observed, but no shrinkage pattern is generated on the paint surface.
In x, coating surface abnormalities such as repellency, dents, and cloudiness are observed on the coating surface.

  (Note 33) Pencil hardness (scratch resistance): The paint film on the test plate was subjected to a pencil scratch test specified in JIS K 5600-5-4 (1999) and evaluated by tearing the paint film.

(Note 34) Workability: In a room at 20 ° C, the coating plate surface of the coated plate is folded outward, and the coated plate is bent at 180 degrees in a vise without interposing anything inside. The state of the coating at the folded part when processing is performed, and the coating plate surface of the coating plate is folded outside in the room at 0 ° C, and two spacers having the same thickness as the coating plate are sandwiched between the above The coating film state of the bent portion when the coated plate was subjected to 2T bending for bending 180 degrees with a vise was evaluated according to the following criteria.
◎ indicates no abnormality such as cracking or peeling on the coating film.
○ indicates a slight crack in the coating film.
Δ indicates considerable cracking in the coating film.
In x, cracks are remarkably observed in the coating film.

(Note 35) Gloss retention (weather resistance):
In the sunshine carbon arc lamp type light resistance and weather resistance test stipulated in JIS B-7533, with respect to the initial gloss measured at 60 ° specular gloss in the coating film tested until the irradiation time was 2,000 hours. The gloss retention (%) was examined.

(Note 36) Film thickness wear resistance (weather resistance):
The film thickness of the coating film tested until the irradiation time was 2,000 hours was measured with a sunshine weatherometer, and the difference from the initial film thickness was determined.

(Note 37) Corrosion resistance:
The test plate used for the “0T bending process” used in the above (Note 34) workability was subjected to a salt spray test. The salt spray test was conducted according to JIS Z-2371, the salt spray test time was 1,000 hours, and the degree of rust generation in the processed part was evaluated according to the following criteria.
◎ indicates that no rust is observed in the processed part.
○ is less than 10% of the length of the processed part although rust is observed in the processed part
Δ is 10% or more of the length of the processed part and the occurrence of rust is observed in less than 50%. × is the occurrence of rust in the processed part of 50% or more of the length of the processed part.

(Note 38) Adhesion:
In accordance with JIS K 5600-5-6 (1999) grid pattern-tape method, 11 knives are used in parallel at vertical and horizontal intervals of about 1 mm using a knife so as to reach the substrate surface of the coated plate. A slit was formed to form a gobang, a cellophane (registered trademark) adhesive tape was attached to the surface, and the gobang eye coating surface after the tape was peeled off was evaluated according to the following criteria.
A: No peeling of the coating film is observed. ○: A slight peeling is observed in a part of the coating film in the knife scratch. Δ: 1 to 20 in which at least all of the UV ink is peeled out of 100 gobangs. X: There are 21 or more of the 100 gobangs from which at least all of the UV ink has been peeled off.

(Note 39) Chemical resistance: The coated surface after each test plate was immersed in a 5% concentration sulfuric acid aqueous solution at 60 ° C. for 3 hours was visually evaluated.
◯: The coating film has no abnormality such as swelling or cracking.
Δ: Either swelling or cracking is observed in the coating film.
X: Swelling or cracking is remarkably observed in the coating film.

  (Note 40) Light transmittance: Each clear paint is applied to a tin plate so as to have a predetermined film thickness (15 μm). Thereafter, it is heated and dried at 230 ° C. for 60 seconds. Next, the coating film is peeled off using mercury by the amalgam method to form a clear single coating film. Each clear clear coating film was measured for a light transmittance of 300 to 500 nm using Hitachi spectrophotometer U-3200 (Hitachi, Ltd.), and the minimum value of the transmittance curve was defined as a light transmittance (%).

  A coated metal plate excellent in coating film hardness, weather resistance (light resistance, film thickness wear resistance), chemical resistance, corrosion resistance, workability, and design properties (metallic matte coating film) can be provided.

It is a cross-sectional electron micrograph of the multilayer coating film before a weather resistance test. It is a cross-sectional electron micrograph of the multilayer coating film after a weather resistance test. The aluminum in the clear coating film is a model diagram of the orientation state of a conventional product. Aluminum in the clear coating film is a model diagram of the orientation state of the product of the present invention.

Explanation of symbols

1. The clear paint film part is shown.
2. The intermediate coating film part is shown.
3. The depleted film thickness is shown.
4). The orientation of aluminum is shown.
5. Indicates ultraviolet light.
6). Indicates that ultraviolet rays are reflected on the surface layer.

Claims (4)

A cured coating film (A1) having a dry film thickness of 1 to 10 μm is formed by a primer coating (A) on a metal plate that may be subjected to chemical conversion treatment on the surface, and a hydroxyl group is formed on the cured coating film (A1). An intermediate coating (B) containing 50 to 120 parts by mass of a pigment component is applied to a total of 100 parts by mass of the solid content of the containing resin and the crosslinking agent, and is cured by heating and cured to a dry film thickness of 5 to 20 μm. A film (B1) is formed, and further, a metallic clear paint (C) having the following characteristics is applied onto the cured coating film (B1) and heat-cured to obtain a cured coating film (C1) having a dry film thickness of 10 to 25 μm. A method of painting a metallic matte design coated metal sheet characterized by forming a metal.
Here, the metallic clear paint (C) contains a hydroxyl group-containing polyester resin (c1) and an amino resin (c2), and the total solid content of c1: 50 to 90 parts by mass and c2: 10 to 50 parts by mass is 100. 1-10 parts by mass of aluminum pigment (c3) having an average particle diameter of 10-22 μm and 0.1-10 parts by mass of acrylic organic resin fine particles (c4) having an average particle diameter of 10-22 μm with respect to parts by mass In addition, the paint is characterized in that a uniform crease pattern is generated on the surface of the coating film when the coating film is cured. The metallic clear paint (C) further contains 0.1 to 15 parts by mass of silica fine powder having an average particle size of 10 μm or less with respect to 100 parts by mass of the total solid content of (c1) and (c2). The method for coating a metallic matte design coated metal sheet according to claim 1. The metallic shine according to claim 1 or 2, wherein in the sunshine carbon arc lamp type light resistance and weather resistance test stipulated in JIS B-7533, film thickness wear after irradiation for 2,000 hours is 3 µm or less. How to paint a matte design painted metal sheet. The light transmittance of the cured coating film (C1) having a dry film thickness of 10 to 25 µm by the metallic clear paint (C) is an average of 10% or less in the visible light region having a wavelength of 400 nm to 700 nm. The method of coating the metallic matte design coated metal sheet according to the item.

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