JP2003245603A - Method for forming luster color coating film and coated article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a luster color coating film capable of realizing a clear white with luster on the coated film and without lowering the bright appearance of aluminium pigment and without browning when viewing the coated film at a shade part from an angle and a coated article obtained by this method. <P>SOLUTION: After forming a luster color base coating film containing an aluminium flaky pigment, especially, which average flake size is 15-25 μm, an average flake thickness is 0.5-1.5 μm and a gradient n in a Rosin-Rammuler diagram is not less than 2.5, a coated article formed by the method for forming the luster color coating film is formed by a first clear coating film containing organic resin fine particles on the luster color base coating film and by a second clear coating film on the first clear coating film. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for forming a glittering coating film and a coated article obtained by this method.

[0002]

2. Description of the Related Art Heretofore, there has been known a technique in which fine particles of organic resin are used to make matte and the surface feel slimy. As a resin sheet that expresses these, Japanese Patent Laid-Open No. 5-2
Japanese Patent No. 54072 discloses that a coating film of a polyurethane resin containing amino acid resin particles is formed on a resin sheet colored with a bright pigment, and a matte surface having a slimy feel to the touch. A colored resin sheet is described. The resin sheet colored with this bright pigment is one in which the matte and surface feel develops a slimy feeling, and regarding the bright feeling of the aluminum flake pigment,
When the coating film is viewed obliquely (shade part), it is darkened, and a clear whiteness is not exhibited.

[0003]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a glossy coating film and to prevent the glitter of the aluminum flake pigment from deteriorating when the coating film is viewed obliquely (shade portion).
The object of the present invention is to provide a method for forming a glittering coating film capable of obtaining a coating film exhibiting a clear whiteness and a coated article obtained by this method.

[0004]

Means for Solving the Problems The present inventors have accomplished the present invention as a result of intensive studies in view of the above problems.

1. After forming a glittering base coating film containing an aluminum flake pigment on a substrate, a first clear coating film containing organic resin fine particles is formed on the above glittering base coating film, and further on the first clear coating film. A method for forming a glittering coating film for forming a second clear coating film.

2. The method for forming a glittering coating film as described above, wherein the content of the aluminum flake pigment in the glittering base coating film is 5 to 25 parts by mass based on 100 parts by mass of the solid content of the vehicle in the coating film.

3. The aluminum flake pigment in the glittering base coating film has an average particle diameter of 15 to 25 μm, an average particle thickness of 0.5 to 1.5 μm, and a gradient n in the Rosin-Rammler diagram of 2.5 or more. Method for forming glittering coating film.

4. The method for forming a glittering coating film as described above, wherein the content of the organic resin fine particles in the first clear coating film is 1 to 20 parts by mass based on 100 parts by mass of the solid content of vehicle in the coating film.

5. The method for forming a glittering coating film as described above, wherein the organic resin particles in the first clear coating film are acrylic resin fine particles.

6. In addition to the aluminum flake pigment in the glittering base coating film, a metal oxide-coated alumina flake pigment in the glittering base coating film, a metal oxide-coated silica flake pigment, a graphite pigment, a metal oxide-coated mica pigment, At least one glittering pigment selected from the group consisting of metallic titanium flake pigments, stainless flake pigments, plate-shaped iron oxide pigments, metal-plated glass flake pigments, metal oxide-coated glass flake pigments, hologram pigments and cholesteric crystalline polymer pigments. The method for forming a glittering coating film, which comprises:

7. The method for forming a glittering coating film, wherein the second clear coating film is formed from a coating material containing a carboxyl group-containing polymer and an epoxy group-containing polymer.

8. A coated article obtained by the above method for forming a glittering coating film.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The constitution of the present invention will be described in detail below.

[Glittering Coating Forming Method] In the glittering coating forming method of the present invention, after forming a glittering base coating containing an aluminum flake pigment on a substrate, the above glittering coating is formed. A first clear coating film containing organic resin fine particles is formed, and a second clear coating film is further formed on the first clear coating film.

[Substrate] Examples of the substrate include metals such as iron, aluminum, copper or alloys thereof; inorganic materials such as glass, cement and concrete; polyethylene resin;
Resins such as polypropylene resin, ethylene-vinyl acetate copolymer resin, polyamide resin, acrylic resin, vinylidene chloride resin, polycarbonate resin, polyurethane resin, epoxy resin and various plastic materials such as FRP; wood, fiber materials (paper, paper, Examples include natural or synthetic materials such as cloth) and processed products thereof.

[Undercoating and Undercoating] In the method for forming a glittering coating film of the present invention, a glittering base coating film containing an aluminum flake pigment is first formed on the substrate directly or through the undercoating film. If the coated object is an automobile body or an automobile part, it is necessary to preliminarily apply a base treatment such as degreasing or chemical conversion treatment to the above-mentioned base material, electrodeposition coating or various primer coatings, intermediate coating, etc. preferable.

When the glittering base coating film is directly formed on the undercoating film on which the undercoating is applied without performing the intermediate coating, the wet-on-wet (W / W) or the wet-on-dry (W) is used. / D).

The above W / W is a method of forming an upper coating film on the lower coating film in an uncured state or a semi-cured state after forming a lower coating film by air drying or the like. On the other hand, the W / D is a method of forming an upper coating film on a lower coating film obtained by baking and curing the lower coating film. It is also possible to apply each coating several times.
When the coating film is baked, it is baked at 80 to 160 ° C for a predetermined time.

An intermediate coating film can be formed on the undercoating film before forming the glittering base coating film on the above-mentioned substrate. What is the undercoat of the lower layer of the intermediate coat? W / D
Therefore, it is preferable to form an intermediate coating film.

The intermediate coating film may be formed of a solvent type paint, an aqueous paint or a powder type paint. The vehicles, pigments, additives added as necessary, etc. of the paint used for forming the intermediate coating film may be those exemplified in the glittering paint to be described later.

The dry film thickness of the intermediate coating film is 20 to 10
0 μm is preferable, and if it is out of this range, the appearance of the coating film may deteriorate. More preferably, it is 30 to 50 μm.

[Glittering base coating film] Next, a glittering base coating film is formed on the intermediate coating film. This glittering base coating film is formed on the above intermediate coating film by the above W / W or W / D, but preferably by W / D. The dry film thickness of the glittering base coating film is 5 to 30.
μm is preferable, and more preferably 10 to 20 μm. If it is less than 5 μm, the hiding property may be insufficient, and if it exceeds 30 μm, the appearance of the coating film may be poor.

The glitter coating used for forming the glitter base coating film of the glitter coating method of the present invention is a coating containing an aluminum flake pigment and a vehicle.

The above-mentioned aluminum flake pigment is a pigment that imparts a hiding property and a metallic feeling to the coating film. Examples of the aluminum flake pigment include leafing, semi-leafing or non-leafing type aluminum flakes prepared by a usual method of pulverizing aluminum flakes with a fatty acid such as stearic acid in a ball mill.

In the present invention, in order to obtain a glittering coating film in which the brilliance and highlight of the aluminum flake pigment are white,
Preferably, particles having an average particle diameter of 15 to 25 μm, an average particle thickness of 0.5 to 1.5 μm, and a particle property having a gradient n of 2.5 or more in the Rosin-Rammler diagram are selectively used.

The average particle diameter is the 50% value of the particle size distribution measured by a laser diffraction type particle size distribution measuring device. The average particle thickness (μm) is a value obtained by the formula [4000 / water surface coating area (cm ² / g)],
The measuring method is, for example, "Aluminum Handbook".
(9th edition issued April 15, 1972, Light Metal Association of Japan; Asakura Shoten), page 1243. In addition, the above-mentioned Rosin-Rammler
The diagram, [R = 100exp (-bD ^n)] (wherein,
R is the cumulative weight% from the maximum particle size to the particle size D, D is the particle size,
b and n are constants), and the gradient n is represented by a straight line connecting cumulative weight% from the maximum particle size to the particle size D in the above particle size diagram. It means the n value of the Rosin-Rammler formula. A specific measurement method is to obtain a particle size distribution using a laser diffraction type particle size distribution measuring device, plot the obtained cumulative distribution for each particle size on a Rosin-Rammler diagram, and move the straight line in parallel to obtain a pole ( Extrapolation line from Pol P) is drawn to obtain n.

When the average particle diameter of the above-mentioned aluminum flake pigment is less than 15 μm, the glittering feeling of the aluminum flake pigment does not sufficiently appear, and when it exceeds 25 μm, the particles become large and the appearance of the coating film does not sufficiently appear. When the average particle thickness is in the range of 0.5 to 1.5 μm, the thickness is relatively thicker than conventional aluminum flake pigments, it is difficult to deform, and the surface smoothness is excellent. It is a requirement to suppress diffuse reflection and enhance the brilliance. When the average particle thickness is less than 0.5 μm, the brilliance cannot be enhanced, and when it exceeds 1.5 μm, the aluminum flake pigment is used. Due to the poor orientation, the appearance of the coating film becomes poor. The particle properties with a gradient n of 2.5 or more in the rosin-Rammler diagram are characterized by a narrow particle size distribution of the aluminum flake pigment, and particles with a uniform particle size suppress diffuse reflection due to fine particles to give a bright feeling. With increasing, coarse particles are also reduced, leading to the formation of a good coating appearance. If the gradient n is less than 2.5, the particle size distribution becomes wide, and the particles on the fine particle side may strengthen the grayish white color peculiar to aluminum flakes, so that a clear whiteness may not be exhibited. The preferable gradient n in the Rosin-Rammler diagram is 2.7 to.
It is 3.5.

As the aluminum flake pigment having the above-mentioned particle properties, for example, atomized aluminum spherical powder whose particle size is previously selected by primary classification or the like is ground by a grinding aid, an aliphatic or aromatic hydrocarbon solvent. It can be obtained by performing wet pulverization treatment with a pulverizer in the coexistence of a medium, sieving in the wet state, and then performing solid-liquid separation with a filter press or the like. The shape of the particles is macroscopically circular or rounded and flat, and the number of irregular fracture surfaces present at the ends of the flakes is extremely small.

The preferred content of the aluminum flake pigment is 5 to 25 parts by mass with respect to 100 parts by mass of the solid content of the vehicle in the coating film. The hiding property of the aluminum flake pigment may be lowered, and a coating film exhibiting clear whiteness may not be obtained, and if it exceeds 25 parts by mass, the coating film appearance may be deteriorated. It is more preferably 5 to 15 parts by mass.

The vehicle contained in the glitter coating material used for forming the glitter coating film of the present invention is one which disperses the above-mentioned aluminum flake pigment, and comprises a resin for coating film formation and, if necessary, a crosslinking agent. Composed of.

Examples of the coating film forming resin constituting the vehicle include (a) acrylic resin, (b) polyester resin, (c) alkyd resin, (d) fluororesin,
(E) Epoxy resin, (f) Polyurethane resin, (g)
Examples thereof include polyether resins, and these can be used alone or in combination of two or more kinds. In particular,
Acrylic resins and polyester resins are preferably used.

Examples of the acrylic resin (a) include copolymers of acrylic monomers and other ethylenically unsaturated monomers. Acrylic monomers that can be used in the above copolymerization include methyl, ethyl, propyl, n-butyl, i-butyl, t of acrylic acid or methacrylic acid.
-Butyl, 2-ethylhexyl, lauryl, phenyl,
Esterification products such as benzyl, 2-hydroxyethyl, 2-hydroxypropyl, ring-opening adducts of 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate with caprolactone, glycidyl acrylate or methacrylate, acrylamide, methacrylamide and N-methylol. Examples thereof include acrylamide and (meth) acrylic acid ester of polyhydric alcohol. Examples of the other ethylenically unsaturated monomers copolymerizable with these include styrene, α-methylstyrene, itaconic acid, maleic acid and vinyl acetate.

Examples of the above-mentioned (b) polyester resin include saturated polyester resin and unsaturated polyester resin, and examples thereof include a condensate obtained by heating and condensing a polybasic acid and a polyhydric alcohol. Examples of the polybasic acid include saturated polybasic acid and unsaturated polybasic acid, and examples of the saturated polybasic acid include phthalic anhydride, terephthalic acid, succinic acid, and the like, and as unsaturated polybasic acid, Examples thereof include maleic acid, maleic anhydride, fumaric acid and the like.
Examples of polyhydric alcohols include dihydric alcohols and trihydric alcohols, and examples of dihydric alcohols include:
Examples thereof include ethylene glycol and diethylene glycol, and examples of the trihydric alcohol include glycerin and trimethylolpropane.

Examples of the alkyd resin (c) include oils and fats and fatty acids (soybean oil, linseed oil, coconut oil, stearic acid, etc.), natural resins (rosin, amber, etc.) in addition to the polybasic acids and polyhydric alcohols. The alkyd resin obtained by reacting the denaturing agent can be used.

As the above-mentioned (d) fluororesin, any one of vinylidene fluoride resin, tetrafluoroethylene resin or a mixture thereof, a polymerizable compound containing a fluoroolefin and a hydroxy group, and other copolymerizable vinyl resins can be used. Examples of the resin include various fluorine-based copolymers obtained by copolymerizing a monomer including a compound.

Examples of the (e) epoxy resin include resins obtained by the reaction of bisphenol and epichlorohydrin. Examples of the bisphenol include bisphenol A and F. Examples of the bisphenol type epoxy resin include Epicoat 828, Epicoat 1001, and Epicoat 100.
4, Epicoat 1007, Epicoat 1009 (all manufactured by Shell Chemical Co., Ltd.), and those obtained by chain extension of these with an appropriate chain extender can also be used.

Examples of the above-mentioned (f) polyurethane resin include resins having a urethane bond obtained from various polyisocyanate compounds and various polyol components such as acrylic, polyester, polyether and polycarbonate. As the polyisocyanate compound, 2,4-tolylene diisocyanate (2,4-TD
I), 2,6-tolylene diisocyanate (2,6-T
DI) and mixtures thereof (TDI), diphenylmethane-4,4'-diisocyanate (4,4'-MD
I), diphenylmethane-2,4'-diisocyanate (2,4'-MDI), and mixtures thereof (MDI),
Naphthalene-1,5-diisocyanate (NDI),
3,3'-dimethyl-4,4'-biphenylene diisocyanate, xylylene diisocyanate (XDI), dicyclohexylmethane diisocyanate (hydrogenated HD
I), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), hydrogenated xylylene diisocyanate (HXDI) and the like can be mentioned. The (g) polyether resin is a polymer or copolymer having an ether bond, and is a polyoxyethylene-based polyether, a polyoxypropylene-based polyether, a polyoxybutylene-based polyether, or bisphenol A or bisphenol. F
There may be mentioned polyether resins having at least two hydroxyl groups per molecule, such as polyethers derived from aromatic polyhydroxy compounds. Further, the above-mentioned polyether resin is reacted with polyvalent carboxylic acids such as succinic acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid and trimellitic acid, or a reactive derivative thereof such as an acid anhydride. The carboxyl group-containing polyether resin thus obtained can be mentioned.

The coating film-forming resin includes a curable type and a lacquer type, but a curable type is usually used. In the case of a curable type, it is used as a mixture with a cross-linking agent such as an amino resin, a (block) polyisocyanate compound, an amine type, a polyamide type, or a polyvalent carboxylic acid, and a curing reaction proceeds at heating or at room temperature. be able to. It is also possible to use a lacquer type coating film-forming resin having no curability and a curable type in combination.

When the vehicle contains a crosslinking agent, the ratio of the coating film forming resin to the crosslinking agent is 90 to 50% by mass of the coating film forming resin and 10 to 50% by mass of the crosslinking agent in terms of solid content. The coating film forming resin is preferably 85 to 60% by mass, and the crosslinking agent is 15 to 40% by mass. When the cross-linking agent is less than 10% by mass (when the coating film forming resin exceeds 90% by mass), the crosslinking in the coating film is insufficient. On the other hand, when the cross-linking agent exceeds 50% by mass (50% by mass of the coating film forming resin
If it is less than 1), the storage stability of the coating composition decreases and the curing rate increases, resulting in a poor coating film appearance.

In addition to the aluminum flake pigment, the glitter coating material may contain other glitter pigments and coloring pigments. Other bright pigments, preferably metal oxide-coated alumina flake pigment,
Metal oxide-coated silica flake pigments, graphite pigments, metal oxide-coated mica pigments, metal titanium flake pigments, stainless flake pigments, plate-shaped iron oxide pigments, metal-plated glass flake pigments, metal oxide-coated glass flake pigments, hologram pigments and At least one bright pigment selected from the group consisting of cholesteric crystal polymer pigments can be mentioned.

Further, as a coloring pigment contained in the glittering paint as required, those conventionally used for paints can be mentioned. As such a pigment, for example, organic pigments such as azo lake pigments and phthalocyanine are used. System pigments, indigo system pigments, perylene system pigments, quinophthalone system pigments, dioxazine system pigments, quinacridone system pigments, isoindolinone system pigments, metal complex pigments, and the like, and examples of inorganic pigments include yellow iron oxide, Examples include red iron oxide, titanium dioxide, and carbon black.

In addition to the above-mentioned components, the above-mentioned glitter coating material includes polyamide wax which is a lubricating dispersion of an aliphatic amide, polyethylene wax which is a colloidal dispersion mainly composed of polyethylene oxide, an anti-settling agent, a curing catalyst, and an ultraviolet ray. Absorbers, antioxidants, leveling agents, surface modifiers such as silicones and organic polymers, anti-sagging agents, thickeners, defoamers, crosslinkable polymer particles (microgels), etc. should be added as appropriate. You can These additives can improve the performance of a paint or a coating film, usually by blending at a ratio of, for example, 15 parts by mass or less with respect to 100 parts by mass of the vehicle (based on solid content).

The glitter coating material is usually provided in a form in which the above constituent components are dissolved or dispersed in a solvent. As the solvent, any solvent that dissolves or disperses the vehicle may be used, and an organic solvent and / or water may be used. Examples of the organic solvent include those commonly used in the field of coating materials. Examples thereof include hydrocarbons such as toluene and xylene, ketones such as acetone and methyl ethyl ketone, esters such as ethyl acetate, cellosolve acetate and butyl cellosolve, and alcohols. Water is preferably used when the use of the organic solvent is regulated from the viewpoint of the environment. In this case, an appropriate amount of hydrophilic organic solvent may be contained.

[First Clear Coating Film] Next, after forming a glittering base coating film containing an aluminum flake pigment, a first clear coating film containing organic resin fine particles is formed on the glittering base coating film. This first clear coating film
W / W or W / D on the glittering base coating film
However, it is preferably formed by W / W. The dry film thickness of the first clear coating film is 10 to 50 μm.
m is preferred. If it is less than 10 μm, it may not be possible to obtain a coating that develops clear whiteness without being blackened when the coating is viewed obliquely (shade part), and if it exceeds 50 μm, the appearance of the coating may be poor. There is a fear. More preferably, it is 10 to 30 μm.

The first clear coating used in the first clear coating of the method for forming a glittering coating of the present invention is a coating containing organic resin fine particles and a vehicle.

The above-mentioned organic resin fine particles are components for obtaining a glittering coating film which develops a clear whiteness without being blackened when the coating film is viewed obliquely (shade part). Examples of the organic resin fine particles (preferably excluding amino acid resin particles) include acrylic resin, polyacrylonitrile resin, polyurethane resin, polyamide resin, polyimide resin and the like. Acrylic resin particles are preferably used from the viewpoint of durability and strength. The average particle size of the organic resin fine particles is preferably 5 to 50 μm. If it is less than 5 μm, the brilliance of the aluminum flake pigment may be deteriorated, and clear whiteness of the shade may not be exhibited. If it exceeds 50 μm, the appearance may be deteriorated. More preferably 1
It is 0 to 30 μm.

The preferred content of the organic resin fine particles is
1-2 with respect to 100 parts by mass of the vehicle solid content in the coating film
It is 0 part by mass. If it is less than 1 part by mass, the clear whiteness of the shade part may not be exhibited, and if it exceeds 20 parts by mass, the appearance of the coating film may be deteriorated and the bright feeling of the aluminum flake pigment may not be exhibited. It is more preferably 5 to 20 parts by mass.

Further, inorganic fine particles may be used in combination in such an amount that the effect of the organic resin fine particles is not impaired. Examples of the inorganic fine particles include fine silica powder, clay, talc, mica and the like. The average particle size of the inorganic fine particles is preferably 1 to 5 μm. When the achromatic colored resin fine particles and the inorganic fine particles are used in combination, it is possible to form a glitter coating film that improves the orientation of the glitter material. In that case, the mass mixing ratio is preferably 0.1 to 0.5 of the inorganic fine particles with respect to the organic resin fine particles 1.

Further, as the pigment that can be added within the range that does not impair the transparency of the vehicle of the first clear paint, additives and solvents that are added as necessary, those exemplified in the above-mentioned glitter paint can be blended. is there.

The first clear coating material may be in the form of organic solvent type, water-based or powder type. The above-mentioned first clear coating material may be in any form of organic solvent type, water-based or powder type. The organic solvent type and the water-based paint may be a one-pack type or a two-pack type such as a two-pack type urethane resin paint.

[Second clear coating film] Next, after forming the first clear coating film, a second clear coating film is formed on the first clear coating film. The second clear coating film is formed on the first clear coating film by the above W / W or W / D, but is preferably formed by W / D.
The dry film thickness of the second clear coating film is preferably 20 to 50 μm, and if it is less than 20 μm, the coating film appearance may be poor, and if it exceeds 50 μm, the coating film appearance may be poor. More preferably, it is 25 to 45 μm.

The second clear coating composition used in the second clear coating film of the method for forming a glittering coating film of the present invention contains a vehicle. As the vehicle, the vehicle described in the glitter coating can be used. Further, a combination of a carboxyl group-containing polymer and an epoxy group-containing polymer described in JP-B-8-19315 discloses an interference pigment for a lower coating film when applied by acid rain resistance measures and a wet-on-wet method. It is preferably used from the viewpoint of not disturbing the orientation of.

Further, pigments that can be added within the range that does not impair the transparency of the vehicle of the second clear paint, additives and solvents that are added as necessary, can be blended with those exemplified in the above-mentioned glitter paint. is there.

The second clear coating material may be in the form of an organic solvent type, an aqueous type or a powder type. The organic solvent type and the water-based paint may be a one-pack type or a two-pack type such as a two-pack type urethane resin paint.

The coating method used to form each of the above coating films is not particularly limited, but when the coating material used is a liquid, a spray method, a roll coater method or the like is preferable, and when it is a powder, electrostatic coating is preferable.

[Coated Product] The coated product of the present invention can be obtained by the above method for forming a glittering coating film. In this coated article, a coating layer which is formed on a substrate and which constitutes the coated article has a glittering base coating film containing an aluminum flake pigment, a first clear coating film containing organic resin fine particles, Further, a second clear coating film is sequentially formed. Here, as a composite effect of each coating film, when a multilayer coating film composed of these is used, the coating film is glossy, and when the coating film is viewed obliquely without decreasing the brilliance of the aluminum flake pigment (shade. Part)
It develops a coating film that develops a clear whiteness without darkening.

[0057]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In addition, the compounding amount represents a mass part unless otherwise specified. In addition, the names of raw materials, paints, and equipment are trade names unless otherwise specified.

[Examples 1 to 23, Comparative Examples 1 to 3] [Preparation of substrate] Dull steel plate (length 300 mm, width 100 m)
m and a thickness of 0.8 mm) was subjected to a chemical conversion treatment using a zinc phosphate treatment agent (“Surfdyne SD2000”, manufactured by Nippon Paint Co., Ltd.), and then a cationic electrodeposition coating (“Power Top U”).
-50 ", manufactured by Nippon Paint Co., Ltd.) was electrodeposited to a dry film thickness of 25 μm. Then, a baking electrodeposition coating film was obtained by baking at 160 ° C. for 30 minutes. Further, an intermediate coating composition (“Olga S-90 Sealer”, manufactured by Nippon Paint Co., Ltd.) was air-spray coated onto the electrodeposition coating film so that the dry film thickness was 40 μm, and baked at 140 ° C. for 30 minutes to be intermediate coated. A coating film was formed to obtain a base material.

[Preparation of glitter coating] Acrylic resin (styrene / methyl methacrylate / ethyl methacrylate /
Hydroxyethyl methacrylate / methacrylic acid copolymer, number average molecular weight of about 20,000, hydroxyl value of 45, acid value of 15, solid content of 50% by mass, and melamine resin (trade name: "Uvan 20SE", manufactured by Mitsui Chemicals, Inc.) , Solid content 60
Mass%) and a vehicle obtained by blending the solid content ratio of 80:20 with the solid content, the average particle diameter, the particle average thickness, the aluminum flake pigment having a gradient n in the Rosin-Rammler diagram shown in Table 1, and If necessary, other pigments were mixed in the proportions shown in Table 1. Then, the organic solvent (toluene / xylene / ethyl acetate / butyl acetate mass ratio = 70 /
15/10/5) and stirred and mixed with a stirrer so that the coating has an appropriate viscosity, to prepare a glitter coating.

[Preparation of first clear coating] Acrylic resin (copolymer of styrene / methyl methacrylate / ethyl methacrylate / hydroxyethyl methacrylate / methacrylic acid, number average molecular weight of about 20,000, hydroxyl value of 4
5, acid value 15, solid content 50 mass%) and melamine resin (trade name: "Uban 20SE", manufactured by Mitsui Chemicals, Inc., solid content 60 mass%) are mixed at a solid content mass ratio of 80:20. The organic resin fine particles shown in Table 1 were blended with the obtained vehicle at the ratio shown in Table 1. Then, the organic solvent (toluene / xylene / ethyl acetate / butyl acetate mass ratio = 70
/ 15/10/5) and the mixture was stirred and mixed with a stirrer so that the viscosity was suitable for coating, to prepare a first clear coating composition.

[Coating film forming method] The above-mentioned base material was air-spray coated with the glittering paint shown in Table 1 so as to have a dry film thickness of 30 μm, and baked at 140 ° C. for 30 minutes to form a glittering base paint film. did. Painting is performed by an electrostatic coating machine ("Auto
REA ", manufactured by ABB Industry Co., Ltd.) at an atomization pressure of 274000 Pa (2.8 kg / cm ² ). Then, the first clear coating material shown in Table 1 was applied to a dry film thickness of 15 μm.
m air spray coating, set for 3 minutes after coating, and then apply the second clear coating shown below to a dry film thickness of 35 μm, set at room temperature for 10 minutes, and at a temperature of 140 ° C. Bake for 30 minutes. The brightness of the obtained coating film was evaluated by the following evaluation method, and the results are shown in Table 1.
It was shown to.

[Second Clear Paint] The following clear paint was used as the second clear paint. 1 ... Acrylic resin solvent-based clear coating (trade name: "Superlac O-130 clear", manufactured by Nippon Paint Co., Ltd.), 2 ... Solvent-based clear coating composed of blend of carboxyl group-containing polymer and epoxy group-containing polymer (trade name) :
"Macflow O-520 clear", manufactured by Nippon Paint Co., Ltd.).

[Evaluation method] Brightness: The bright feeling of the multilayer coating film was visually evaluated. 3 ... Brightness of the aluminum flake pigment does not deteriorate, and when the multilayer coating film is viewed obliquely (shade part), it does not turn black, and expresses clear whiteness remarkably. 2 ... Brightness of the aluminum flake pigment Does not decrease, and when the coating film is viewed obliquely (shade part), it does not turn black and expresses a clear whiteness 1. The brightness of the aluminum flake pigment decreases and when the coating film is viewed obliquely (Shade part) darkened, no clear white appearance

[0064]

[Table 1]

As is clear from the results of Table 1, this example is a multilayer coating film formed by the coating film forming method using the glitter coating composition of the present invention. Of the multi-layered coating film showing clear whiteness without being blackened when the coating film was viewed obliquely (shaded portion).

On the other hand, in the comparative example, the multi-layer coating film as obtained in the above-mentioned example was not obtained.

[0067]

The method for forming a glittering coating film of the present invention comprises the steps of forming a glittering base coating film containing an aluminum flake pigment on a substrate, and then adding organic resin fine particles to the glittering base coating film. Since the first clear coating film is formed and then the second clear coating film is formed on the first clear coating film, the coated product formed by this method does not reduce the brilliance of the aluminum flake pigment and When viewed obliquely (shade part), it is possible to express a clear whiteness without becoming black.

Since the multi-layer coating film of the present invention exhibits the above-mentioned brilliance, it has a brilliance in vehicle skins of automobiles, motorcycles and the like, parts thereof, outer surfaces of various containers, coil coating, furniture, home appliance industry, communication industry and the like. Is preferably used in the field where is required.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09D 5/29 C09D 5/29 133/00 133/00 201/00 201/00 201/06 201/06 F term (reference) 4D075 AE03 AE17 CB03 CB06 CB13 DB01 DB02 DB06 DB07 DB11 DB12 DB13 DB18 DB20 DB21 DB31 DB36 DB38 DB40 DB43 DB47 DB48 DB50 DB53 DB61 EA02 EA06 EA07 EA19 EA23 EA43 EB16 EB22 EB33 EB35 EB36 EB37 EB38 EB56 EC01 EC02 EC03 EC04 EC07 EC11 EC23 EC24 EC53 EC54 EC60 4J038 CD091 CG001 CG002 DB001 DD001 DF001 DG001 GA06 GA07 HA036 HA066 HA216 HA446 HA486 KA08 KA20 MA02 PB03

Claims (8)

[Claims] 1. A bright base coating film containing an aluminum flake pigment is formed on a base material, and then a first clear coating film containing organic resin fine particles is formed on the bright base coating film. A method for forming a glittering coating film, which comprises forming a second clear coating film on the clear coating film. 2. The glitter coating according to claim 1, wherein the content of the aluminum flake pigment in the glitter base coating film is 5 to 25 parts by mass based on 100 parts by mass of the solid content of vehicle 100 in the coating film. Film forming method. 3. The aluminum flake pigment in the glittering base coating film has an average particle diameter of 15 to 25 μm, an average particle thickness of 0.5 to 1.5 μm, and a gradient n in the rosin-Rammler diagram of 2.5. The method for forming a glittering coating film according to claim 1 or 2, which is the above. 4. The content of the organic resin fine particles in the first clear coating film is 1 to 20 parts by mass with respect to 100 parts by mass of the solid content of vehicle 100 in the coating film. The method for forming a glittering coating film according to the item. 5. The method for forming a glittering coating film according to claim 1, wherein the organic resin particles in the first clear coating film are acrylic resin fine particles. 6. In addition to the aluminum flake pigment in the glittering base coating film, a metal oxide-coated alumina flake pigment, a metal oxide coating silica flake pigment, a graphite pigment, and a metal oxide are further contained in the glittering base coating film. At least one selected from the group consisting of a substance-coated mica pigment, a metal titanium flake pigment, a stainless flake pigment, a plate-shaped iron oxide pigment, a metal-plated glass flake pigment, a metal oxide-coated glass flake pigment, a hologram pigment and a cholesteric crystal polymer pigment. The method for forming a glittering coating film according to any one of claims 1 to 5, which comprises one kind of glittering pigment. 7. The method for forming a glittering coating film according to claim 1, wherein the second clear coating film is formed from a coating material containing a carboxyl group-containing polymer and an epoxy group containing polymer. 8. A coated article obtained by the method for forming a glittering coating film according to any one of claims 1 to 7.