JP2011001536A - Coating composition, method for forming coating film, and coating film structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating composition which can form a coating film which excels in feeling of metal, and has a texture in which the change of hue by an observation angle is controlled onto various industrial products of an automobile body outer panel or the like, and to provide a method for forming a coating film and a coating film structure.SOLUTION: The coating composition includes an optical interference property pigment, a color pigment, and a multi-color brilliant pigment, and is characterized in that the relation between an interference color in highlight of the optical interference property pigment and an interference color in highlight of the multi-color brilliant pigment, and the relation between a color of the color pigment and an interference color in highlight of the multi-color brilliant pigment are in a relation of a complementary color. The method for forming a coating film and the coating film structure are disclosed.

Description

The present invention relates to a coating composition that can form a coating film that has an excellent metallic feeling, changes in saturation depending on an observation angle, and exhibits a texture in which a change in hue is suppressed.

For industrial products such as automobiles, in order to increase the product power, there are cases in which a metallic paint color whose appearance changes depending on the observation angle is applied. In particular, a paint color whose hue changes greatly depending on the observation angle is attracting attention as giving a three-dimensional effect to the material.

  Patent Document 1 relates to a coating composition capable of forming a glittering coating film exhibiting a three-dimensional glittering feeling, and includes a flake pigment made of cholesteric liquid crystal polymer and an interference mica pigment having a different hue of highlight. Things are disclosed. The coating film obtained by applying the coating composition has a design that has a large hue change and excellent attractiveness from highlight (observation of the coating film from the front) to shade (observation of the coating film from an oblique direction). As shown, there is a concern that the saturation is high from the highlight to the shade and the hue may change too much. In this case, there is a problem that the impression of the painted industrial product becomes unnatural.

JP 2003-206444 A

An object of the present invention is to provide a coating composition capable of forming a textured coating film that has excellent metallic feeling, changes in saturation depending on the observation angle, and suppresses changes in hue.

The present invention
1. A coating composition comprising a light interference pigment, a color pigment, and a multicolor glitter pigment, wherein the relationship between the interference color and the color of the color pigment in the highlight of the multicolor glitter pigment and the highlight of the light interference pigment A coating composition characterized in that the relationship between the interference color and the interference color in the highlight of the multi-color glitter pigment is a complementary color relationship;
2. 2. The coating composition according to item 1, wherein the multi-color glitter pigment is scaly silica coated with a metal oxide,
3. Item 3. The coating composition according to Item 1 or 2, wherein the light interference pigment is aluminum oxide coated with a metal oxide.
4). The coating composition according to any one of claims 1 to 3, wherein the color pigment is a transparent pigment. A coating film forming method of further applying a top clear coating material on the coating film obtained by applying the coating composition according to any one of items 1 to 4 on a substrate;
6.5 Coating film structure formed by the coating film forming method described in 6.5
About.

ADVANTAGE OF THE INVENTION According to this invention, the coating composition which can form the coating film of the texture which is excellent in a metal feeling, changes the saturation with the observation angle, and the change of the hue was suppressed can be obtained.

The coating composition of the present invention includes a light interference pigment, a color pigment, and a multicolor glitter pigment. The relationship between the interference color and the color of the colored pigment in the highlight of the multicolor glitter pigment, and the relationship between the interference color of the highlight of the light interference pigment and the interference color in the highlight of the multicolor glitter pigment are complementary colors. is there.

  Light interference pigments are coated with metal oxides such as titanium dioxide and iron oxide that have a different refractive index from the surface of scaly substrates such as mica, artificial mica, glass, iron oxide, aluminum oxide and various metals. Means a pigment that exhibits an interference color by the metal oxide layer.

  Specifically, the interference color in the highlight of the light interference pigment and the multi-color glitter pigment described later is a paint composition containing only the light interference pigment or the multi-color glitter pigment as a colorant. It means the color obtained by irradiating light from an angle of 45 ° to the coating film obtained in this way and measuring the color in the direction of 15 ° with respect to the regular reflection light. In addition, the color of the color pigment means that the coating film obtained by applying a paint containing only the color pigment as a colorant is irradiated with light from an angle of 45 °, and in the direction of 45 ° with respect to specular reflection light. It means the color obtained by colorimetry.

  The two colors having a complementary color relationship means that the difference Δh in hue angle h in the L * C * h color system of each color is 180 °. The L * C * h color system is a color system designed based on the L * a * b * color system specified by the International Commission on Illumination in 1976 and adopted in JIS Z 8729. H represents a hue angle, and is an angle moved counterclockwise with the red axis as 0 ° in the chromaticity diagram. The hue angle difference Δh of each color means the minimum value of the difference between the hue angle h1 of one color and the hue angle h2 of the other color.

  Ideally, in the coating composition of the present invention, the hue angle difference Δh between the interference color in the highlight of the light interference pigment and the interference color in the highlight of the multicolor glitter pigment described later is 180 °. Although it is preferable from the viewpoint of suppressing a hue change due to an observation angle of a coating film obtained by applying the coating composition of the present invention, in practice, it is marketed as a light interference pigment and a multicolor glitter pigment. Therefore, it is preferable to combine those having Δh of 120 ° or more and 180 ° or less, more preferably 130 ° or more and 180 ° or less, and more preferably 150 ° or more and 180 ° or less. It is to be.

  In the present specification, the interference color in the highlight of a light interference pigment and a multicolor glitter pigment described later is a resin component 100 solid content comprising a hydroxyl group-containing acrylic resin (hydroxyl value 100, number average molecular weight 20000) and a melamine resin. An organic solvent-type paint having a solid content of about 25% by blending 15 parts by mass of a light interference pigment or multi-color glitter pigment per mass part, stirring and mixing, adding a solvent and diluting to an appropriate viscosity for coating. The paint obtained by preparing the above is air-sprayed on a coated plate on which a black (N-2) coating film has been formed in advance to a film thickness of 18 μm as a cured coating film, and left at room temperature for 15 minutes. Next, a clear paint (Lugabe Kukuriya, manufactured by Kansai Paint Co., Ltd., trade name, acrylic resin / amino resin type, organic solvent type) is used as a cured coating film on the uncured coating surface to be 35 μm. The coating film obtained by air spray coating and leaving at room temperature for 15 minutes, followed by heating and drying at 140 ° C. for 30 minutes using a hot air dryer, was applied to MA-manufactured by X-Rite. 68II (trade name, multi-angle spectrophotometer) is used to define the colorimetric value measured based on the spectral reflectance received at 15 ° with respect to the specularly reflected light.

  Further, the color of the color pigment described below specifically includes 15 parts by mass of the color pigment per 100 parts by mass of a resin component composed of a hydroxyl group-containing acrylic resin (hydroxyl value 100, number average molecular weight 20000) and a melamine resin. Mixing, stirring and mixing, diluting to an appropriate viscosity for painting, and preparing a gray (N-6) coating film in advance from a paint obtained by preparing an organic solvent-type paint having a solid content of about 25% It is obtained by applying air spray on the coated plate to a thickness of 30 μm as a cured coating film, leaving it at room temperature for 15 minutes, and then heating and drying at 140 ° C. for 30 minutes using a hot air dryer. The obtained coating film is defined by colorimetric values measured using MA-68II (trade name) manufactured by X-Rite.

  In the coating composition of the present invention, it is preferable to use a coating of titanium dioxide on the surface of scaly aluminum oxide as a light interference pigment from the viewpoint of the metallic feeling of the coating film obtained by painting. As for the size of the light interference pigment, it is preferable to use a pigment having an average particle diameter in the range of 5 to 25 μm from the viewpoint of the finished finish of coated film and particle feeling, and more preferably the particle diameter is 7 It is in the range of -20 μm, particularly preferably in the range of 8-18 μm. It is preferable to use a thickness in the range of 0.05 to 0.5 μm. The particle diameter and thickness here mean numerical values obtained by observing the light interference pigment with an optical microscope or an electron microscope.

  The content of the light-interfering pigment in the coating composition in the present invention is the resin solid content in the coating composition from the viewpoint of the effect that the hue changes depending on the observation angle of the coating film obtained by coating and the finish. The total content is preferably in the range of 1 to 20 parts by mass, more preferably in the range of 2 to 18 parts by mass, and particularly preferably in the range of 3 to 15 parts by mass with respect to 100 parts by mass. In addition, as a total amount of the multicolor glitter pigment and the light interference pigment described later, the total amount is 100 parts by mass of the resin solid content in the coating composition from the viewpoint of the finish of the coating film obtained by coating. Is preferably in the range of 1 to 20 parts by mass, more preferably in the range of 2 to 18 parts by mass, and particularly preferably in the range of 3 to 15 parts by mass.

  The coating composition of the present invention contains a multicolor glitter pigment. Multi-color glitter pigments are glitter pigments that give the effect of changing the hue depending on the observation angle when blended in a paint composition. Specifically, for example, mica, artificial mica, glass, silica , Iron oxide, aluminum oxide and various metals, such as zirconium oxide, cerium oxide, titanium dioxide, iron oxide, zinc sulfide, zinc sulfide, magnesium fluoride, aluminum fluoride, sodium fluoride, silicon oxide Selected from those having different refractive indices from aluminum oxide, thorium fluoride, and the like, and pigments or metal oxides in which three or more layers of interference films are laminated. And scaly silica coated with. In addition, the size of the multicolor glitter pigment can be the same as that of the light interference pigment in terms of the degree of hue change of the coated film and the finish.

  In the present invention, it is particularly preferable to use scaly silica coated with a metal oxide because a coating film obtained by coating is excellent in weather resistance and is easily available. Scale-like silica coated with metal oxide is obtained by coating scale-like silica, which is a substrate having a smooth surface and a uniform thickness, with a metal oxide having a refractive index different from that of the substrate. Since the thickness of the physical layer is also uniform, when blended with a coating composition, the coating film obtained by coating undergoes a large color change from highlight to shade.

  The content of the multicolor glitter pigment in the coating composition in the present invention is the resin solids in the coating composition from the viewpoint of the effect that the hue changes depending on the observation angle of the coating film obtained by coating and the finish. The total amount is preferably in the range of 1 to 20 parts by mass, more preferably in the range of 2 to 18 parts by mass, and particularly preferably in the range of 3 to 15 parts by mass with respect to 100 parts by mass.

  The coating composition of the present invention contains a color pigment having a complementary color relationship with the interference color in the highlight of the multicolor glitter pigment. By this combination, the hue change due to the observation angle of the coating film formed by coating is suppressed, and an effect capable of forming a coating film having a preferable design is achieved.

  The colored pigment in the present invention is not particularly limited as long as the color has a complementary color relationship with the interference color in the highlight of the multi-color glitter pigment, specifically, a transparent iron oxide pigment, Composite metal oxide pigments such as titanium yellow, azo pigments, quinacridone pigments, diketopyrrolopyrrole pigments, perylene pigments, perinone pigments, benzimidazolone pigments, isoindoline pigments, isoindolinone pigments, metals Any one or more of chelate azo pigments, phthalocyanine pigments, indanthrone pigments, dioxane pigments, selenium pigments, indigo pigments and the like can be used in combination.

  In the present invention, it is particularly preferable to use a transparent color pigment among the above-mentioned color pigments from the viewpoint of the depth and transparency of the coating film obtained by coating. Specifically, the transparent coloring pigment is blended so that the pigment amount is 20 parts by mass based on 100 parts by mass of the resin solid content in the paint, and the paint is smoothed so that the cured coating thickness is 30 μm. The coated film that was coated on a hard PTFE plate, cured, and peeled was measured with a spectrophotometer MPS-2450 (trade name, manufactured by Shimadzu Corporation), and the light transmittance in the visible light region (wavelength 400 nm to 700 nm) was 90% or more. The average primary particle diameter is 100 nm or less.

In the present invention, the content of the color pigment in the coating composition is the resin solid content 100 in the coating composition from the viewpoint of the effect that the hue changes depending on the observation angle of the coating film obtained by coating and the finish. It is preferably within a range of 0.01 to 20 parts by mass, more preferably within a range of 0.1 to 10 parts by mass, and particularly preferably within a range of 0.5 to 3 parts by mass with respect to parts by mass. .
From the point of finish, 5 parts by mass or less is preferable with respect to 100 parts by mass of the resin solid content in the coating composition, and more preferably in the range of 0.1 to 3 parts by mass.

  The coating composition of the present invention can usually contain a resin component as a vehicle. Specifically, the resin component includes a base resin such as an acrylic resin, a polyester resin, an alkyd resin, or a urethane resin having a crosslinkable functional group such as a hydroxyl group, and a melamine resin, a urea resin, or a polyisocyanate as necessary. A combination of a crosslinking agent such as a compound (including a block body) is used, and these are used by being dissolved or dispersed in a solvent such as an organic solvent and / or water.

  Furthermore, various additives such as a solvent such as water or an organic solvent, a pigment dispersant, an antisettling agent, a curing catalyst, an antifoaming agent, an antioxidant, and an ultraviolet absorber are added to the coating composition of the present invention as necessary. An agent, extender, etc. can be appropriately blended.

  The coating composition of the present invention is prepared by mixing and dispersing the aforementioned components. The solid content at the time of painting is adjusted to 12 to 50% by mass, preferably 15 to 30% by mass based on the coating composition, and the viscosity at 20 ° C. is adjusted to 15 to 20 seconds / ford cup # 3. It is preferable to keep it.

  The coating composition of the present invention can be applied by a method such as electrostatic coating, air spray, airless spray, etc., and its film thickness should be in the range of 10 to 45 μm based on the cured coating film. From the viewpoint of the smoothness of the coating film. The coating film of the coating composition of the present invention can usually be crosslinked and cured at a temperature of about 70 to about 150 ° C.

  The coating film forming method of the present invention relates to a method of coating the coating composition on a substrate and curing and drying the coating composition.

  In the coating film forming method of the present invention, the base material is a metal such as iron, zinc or aluminum, an alloy containing these, a molded product plated or vapor-deposited with these metals, and glass, plastic or foam. For example, a molded article by a body or the like can be given. Depending on these materials, it can be appropriately degreased or surface treated to form a substrate. Furthermore, an undercoat film or an intermediate coat film can be formed on the substrate to form a substrate, and these are particularly preferable.

  The undercoat film is formed to conceal the surface of the material or impart anticorrosion and rustproofness to the material, and can be obtained by applying an undercoat paint, drying and curing. it can. The type of the undercoat paint is not particularly limited, and examples thereof include an electrodeposition paint and a solvent-type primer.

  The intermediate coating film is formed to conceal the undercoat film or impart adhesion, chipping resistance, etc., and is a dry-cured undercoat film or an uncured undercoat film. It can be obtained by applying an intermediate coating on top, drying and curing. The type of intermediate coating is not particularly limited, and known ones can be used. For example, an organic solvent-based or water-based intermediate coating containing a thermosetting resin composition and a color pigment as essential components can be preferably used. .

  In the case where an undercoat film or an intermediate coat film is formed as a substrate, the undercoat film or the intermediate coat film can be heated, and the coating composition of the present invention can be applied after crosslinking and curing. Alternatively, the undercoating film and / or the intermediate coating film can be applied in an uncured state.

  In the coating film forming method of the present invention, a top clear coating film is formed by further coating one or more top clear coatings on the coating film obtained by coating the above coating composition on a substrate. Can be made.

  The top clear coating in the method for forming a coating film of the present invention is a liquid that forms a colorless or colored transparent coating film comprising a resin component and a solvent as main components, and further blending with other coating additives as required. It is a paint.

  As the top clear coating in the method of the present invention, conventionally known ones can be used without limitation. For example, a liquid or powdery coating composition containing a base resin and a crosslinking agent can be applied. Examples of the base resin include acrylic resin, polyester resin, alkyd resin, fluororesin, urethane resin, and silicon-containing resin containing a crosslinkable functional group such as a hydroxyl group, a carboxyl group, a silanol group, and an epoxy group. It is done. As a crosslinking agent, a melamine resin capable of reacting with the functional group of the base resin, urea resin, polyisocyanate compound, block polyisocyanate compound, epoxy compound or resin, carboxyl group-containing compound or resin, acid anhydride, Examples thereof include alkoxysilane group-containing compounds or resins. Further, if necessary, additives such as a solvent such as water and an organic solvent, a curing catalyst, an antifoaming agent, an ultraviolet absorber, a rheology control agent, an antioxidant, and a surface conditioner can be appropriately blended.

  A color pigment can be blended with the top clear coating in a timely manner within a range not impairing transparency. As the color pigment, one or a combination of two or more conventionally known pigments for ink and paint can be blended. The amount of addition may be determined as appropriate, but is 30 parts by mass or less, preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the resin solid content in the clear coating film.

  The top clear coating can be applied by methods such as electrostatic coating, air spray, airless spray, etc., and the film thickness is preferably in the range of 5 to 40 μm based on the cured coating film. The top clear coating itself can be crosslinked and cured at a temperature of about 70-150 ° C.

  The coating film forming method of the present invention is a so-called 2C2B process in which the coating composition of the present invention is applied, heated, dried and cured, and then the top clear coating is applied on the coated film, heated, and dried and cured. However, a multi-layer coating film can also be obtained by the so-called 2C1B process in which the top clear paint is applied in an uncured state after the coating composition is applied, and then heated to cure them simultaneously. .

  The coating film structure of the present invention relates to the coating film structure obtained by the coating film forming method.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to only these examples. “Part” and “%” are based on mass.
Next, an Example is given and this invention is demonstrated more concretely.
(Production Example 1) Production of hydroxyl group-containing acrylic resin 50 parts of ethylene glycol monoethyl ether acetate was charged in a reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser and dropping device, stirred and mixed, and the temperature was raised to 135 ° C. Warm up. Subsequently, the following monomer / polymerization initiator mixture was dropped into a reaction vessel maintained at the same temperature over 3 hours, and aging was performed for 1 hour after the completion of the dropping. Thereafter, a mixture of 10 parts of ethylene glycol monoethyl ether acetate and 0.6 parts of 2,2′-azobis (2-methylpropionitrile) was added dropwise over 1 hour 30 minutes maintained at the same temperature, and further 2 hours. Aged. Next, ethylene glycol monoethyl ether acetate was distilled off under reduced pressure to obtain a hydroxyl group-containing acrylic resin having a hydroxyl value of 54 mgKOH / g, a number average molecular weight of 20,000, and a resin solid content of 65% by mass. Here, the number average molecular weight means that measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.
Monomer / polymerization initiator mixture:
38 parts of methyl methacrylate, 17 parts of ethyl acrylate, 17 parts of n-butyl acrylate, 7 parts of hydroxyethyl methacrylate, 20 parts of lauryl methacrylate and 1 part of acrylic acid and 2,2′-azobis A mixture consisting of 2 parts of (2-methylpropionitrile).
(Production Example 2) Production of acrylic resin emulsion Thermometer, thermostat, stirrer, reflux condenser and reactor equipped with 130 parts by mass of deionized water, Aqualon KH-10 (trade name, surfactant, No. 1) 0.52 parts by mass) (manufactured by Ichi Kogyo Seiyaku Co., Ltd.) was charged, stirred and mixed in a nitrogen stream, and heated to 80 ° C. Next, 1% of the total amount of the following monomer emulsion (1) and 5.3 parts by mass of 6% ammonium persulfate aqueous solution were introduced into the reaction vessel and maintained at 80 ° C. for 15 minutes. Then, the remaining monomer emulsion (1) was dripped in the reaction container hold | maintained at the same temperature over 3 hours, and it age | cure | ripened for 1 hour after completion | finish of dripping. Thereafter, the following monomer emulsion (2) was added dropwise over 1 hour, and after aging for 1 hour, the mixture was cooled to 30 ° C while gradually adding 40 parts by mass of a 5% dimethylethanolamine aqueous solution to the reaction vessel, It was discharged while being filtered through nylon cloth, and the average particle size was 100 nm (submicron particle size distribution measuring device “COULTER N4 type” (manufactured by Beckman Coulter, Inc.) and diluted with deionized water and measured at 20 ° C.). An acrylic resin emulsion having a solid content concentration of 30% was obtained. The obtained acrylic resin had an acid value of 33 mgKOH / g and a hydroxyl value of 25 mgKOH / g.

  Monomer emulsion (1): 42 parts by weight of deionized water, 0.72 parts by weight of Aqualon KH-10, 2.1 parts by weight of methylenebisacrylamide, 2.8 parts by weight of styrene, 16.1 parts by weight of methyl methacrylate, ethyl acrylate Monomer emulsion (1) obtained by mixing and stirring 28 parts by mass and 21 parts by mass of n-butyl acrylate.

Monomer emulsion (2): 18 parts by weight of deionized water, 0.31 parts by weight of Aqualon KH-10, 0.03 parts by weight of ammonium persulfate, 5.1 parts by weight of methacrylic acid, 5.1 parts by weight of 2-hydroxyethyl acrylate Monomer emulsion (2) obtained by mixing and stirring 3 parts by mass of styrene, 6 parts by mass of methyl methacrylate, 1.8 parts by mass of ethyl acrylate and 9 parts by mass of n-butyl acrylate.
(Production Example 3) Polyester resin production Thermometer, thermostat, stirrer, reflux condenser and reaction vessel equipped with water separator, trimethylolpropane 109 parts by mass, 1,6-hexanediol 141 parts by mass, hexahydro anhydride 126 parts by mass of phthalic acid and 120 parts by mass of adipic acid were charged, and the temperature until reaching 160 ° C. to 230 ° C. was increased to 3 hours, and then a condensation reaction was performed at 230 ° C. for 4 hours. Subsequently, in order to add a carboxyl group to the obtained condensation reaction product, 38.3 parts by mass of trimellitic anhydride was further added, reacted at 170 ° C. for 30 minutes, and then diluted with 2-ethyl-1-hexanol. Thus, a polyester resin solution having a solid content concentration of 70% was obtained. The obtained polyester resin had an acid value of 46 mgKOH / g, a hydroxyl value of 150 mgKOH / g, and a weight average molecular weight of 6,400. Here, the weight average molecular weight means that measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.
(Production Example 4) Preparation of Colored Pigment Dispersion 1 To 225 ml mayonnaise bottle, 7.4 parts of GREEN L8730 (trade name, chlorinated copper phthalocyanine green pigment, average particle size 40 nm, manufactured by BASF) was produced in Production Example 3. 53 parts of the obtained polyester resin solution and 50 parts of deionized water were blended, and 130 parts of 1.5 mm zirconia beads were added and sealed, and dispersed for 120 minutes using a shaking paint conditioner. After dispersion, 100-mesh wire mesh filtration was performed to remove the zirconia beads, and a colored pigment dispersion 1 was obtained.
(Production Example 5) Preparation of Colored Pigment Dispersion 2 To 225 ml mayonnaise bottle, 7.4 parts of MONARCH1300 (trade name, high jet black carbon black pigment, manufactured by Cabot Specialty Chemicals), polyester obtained in Production Example 3 A resin solution (53 parts) and deionized water (50 parts) were mixed, and 1.5 mm-diameter zirconia beads (130 parts) were added and sealed, and dispersed using a shaking paint conditioner for 120 minutes. After the dispersion, 100-mesh wire mesh filtration was performed to remove zirconia beads, and a colored pigment dispersion 2 was obtained.
(Production Example 6) Preparation of high-concentration glitter pigment liquid 1 In a stainless steel beaker, COLOR STREAM T20-01 WNT Viola Fantasy (trade name, titanium oxide-coated silica flake multicolor glitter pigment, manufactured by Merck & Co., Inc.) 100 parts, 130 parts by mass of ethylene glycol monobutyl ether was mixed with stirring to obtain a high-concentration bright pigment liquid 1.
(Production Example 7) Preparation of high-concentration glitter pigment liquid 2 In a stainless steel beaker, 100 parts of Xiallic T60-24 WNT Stellar Green (trade name, titanium oxide-coated aluminum oxide pigment, interference color = green, manufactured by Merck & Co., Inc.) Then, 130 parts of ethylene glycol monobutyl ether was mixed with stirring to obtain a high-concentration bright pigment liquid 2.
(Measurement of interference color of bright pigment and color of colored pigment)
The interference color of the luster pigment used in the examples and comparative examples and the color of the color pigment were measured in the following manner, and the results are shown in Table 1.

  The interference color in the highlight of the glitter pigment is 15 parts of glitter pigment per 100 parts of resin solid content comprising a hydroxyl group-containing acrylic resin (hydroxyl value 100, number average molecular weight 20000) and melamine resin, and stirred and mixed. Add a solvent and dilute it to a viscosity suitable for coating to prepare an organic solvent-type paint with a solid content of about 25%. As a cured coating film, it was sprayed with air spray to a film thickness of 18 μm, left at room temperature for 15 minutes, and then a clear paint (Lugabe Kukuriya, manufactured by Kansai Paint, trade name, (Acrylic resin / amino resin type, organic solvent type) as a cured coating film, air sprayed to 35 μm, left at room temperature for 15 minutes, and then heated at 140 ° C. for 30 minutes using a hot air dryer Spectral reflection of the coating film obtained by heating and drying using MA-68II (trade name, multi-angle spectrophotometer) manufactured by X-Rite, received at 15 ° with respect to specular reflection light. The hue angle in the L * C * h color system measured based on the rate is indicated by h.

  Specifically, the color of the color pigment specifically includes 15 parts of the color pigment per 100 parts of resin solid content comprising a hydroxyl group-containing acrylic resin (hydroxyl value 100, number average molecular weight 20000) and melamine resin, and the mixture is stirred and mixed. The paint obtained by diluting to an appropriate viscosity for coating and preparing an organic solvent-type paint having a solid content of about 25% is applied to a cured coating film on a coating plate on which a gray (N-6) paint film has been formed in advance. The coating film obtained by air spray coating to a film thickness of 30 μm, left at room temperature for 15 minutes, then heated and dried at 140 ° C. for 30 minutes using a hot air drier -Indicates the hue angle h in the L * C * h color system measured based on the spectral reflectance received at 45 ° with respect to specularly reflected light using MA-68II (trade name) manufactured by Rite. It was.

Examples 1-5, Comparative Examples 1-4
Per 100 parts of resin component (solid content) consisting of 75 parts of a hydroxyl group-containing acrylic resin obtained in Production Example 1 and 25 parts of Uban 28-60 (trade name, butyl etherified melamine resin, manufactured by Mitsui Chemicals, Inc.) Color pigments were blended in the ratios shown in Table 2, mixed with stirring, diluted to an appropriate viscosity for coating, and organic solvent-type paints having a solid content of about 25% were prepared. Examples 1 to 5 and Comparative Examples 1 to The coating composition used for No. 4 was prepared.

Example 6
100 parts of the acrylic resin emulsion obtained in Production Example 2, 51.8 parts of the polyester resin solution obtained in Production Example 3, 6.7 parts of the colored pigment dispersion 1 obtained in Production Example 4, and 5 of Production Example 5 4 parts of the obtained colored pigment dispersion 2, 11.5 parts by mass of the high-concentration glitter pigment liquid 1, 11.5 parts by mass of the high-concentration glitter pigment liquid 2 and Cymel 325 (trade name, Nippon Cytec Industries, Ltd.) 37.5 parts of melamine resin, solid content 80%), and primal ASE-60 (trade name, manufactured by Rohm and Haas, polyacrylic acid thickener), 2- (dimethylamino) ) Ford Cup No. at pH 8.0, paint solids 25%, 20 ° C. with addition of ethanol and deionized water. A water-based coating composition with a viscosity of 40 and a viscosity of 40 seconds was prepared.

The ratio of the glitter pigment and the color pigment in the coating composition prepared in Example 6 is the same as in Example 4.
(Creation of test plate)
Cationic electrodeposition paint "ELECRON 9400HB" (trade name: manufactured by Kansai Paint Co., Ltd., epoxy resin polyamine-based cation resin) (Using a block polyisocyanate compound as a curing agent) is electrodeposited so as to have a film thickness of 20 μm based on the cured coating film, and heated at 170 ° C. for 20 minutes to be crosslinked and cured to be electrodeposited. A membrane was obtained.

On the obtained electrodeposition coating surface, an intermediate coating “Lugabek intermediate coating gray” (trade name: manufactured by Kansai Paint Co., Ltd., polyester resin / melamine resin type, organic solvent type) is applied by air spray. Based on the film, it was coated to a film thickness of 30 μm, heated at 140 ° C. for 30 minutes to be crosslinked and cured, and a coated plate on which an intermediate coating film was formed was used as a base material.
The coating composition prepared in Examples and Comparative Examples was applied to the base material prepared in the coating (1) using a REA gun, and the cured coating film was 25 μm under the conditions of a boot temperature of 25 ° C. and a humidity of 75%. Then, leave it at room temperature for 15 minutes, and then apply a clear paint (Lugabe Clear, manufactured by Kansai Paint, trade name, acrylic resin / amino resin, organic solvent type) to these uncured coating surfaces. ) Was coated as a cured coating film at 25-35 [mu] m under the conditions of a boot temperature of 25 [deg.] C. and a humidity of 75% using a mini-bell type rotary electrostatic coating machine. After coating, the sample was allowed to stand at room temperature for 15 minutes, and then heated in a hot-air circulating drying oven at 140 ° C. for 30 minutes to simultaneously dry and cure the multilayer coating film to obtain a test plate.
(Evaluation of design properties)
The design properties of the test plate were evaluated in the following manner, and the results are shown in Table 2.

(1) Hue change visually according to observation angle: The prepared coated plate is illuminated with an artificial sun lamp (manufactured by Celick, color temperature 6500K), and the angle with respect to the illumination of the test plate is changed to observe, highlight (front) to The hue change to the shade (squash) was visually evaluated.
A: Hue change is moderately suppressed.
○: Hue change is suppressed.
Δ: Little or excessive hue change.
X: There is no hue change or it is excessive excessively.
Δh: Δh (difference in hue angle h in the L * C * h color system) of the prepared coated plate is 15 ° with respect to regular reflection light using MA-68II (trade name) manufactured by X-Rite. And a hue angle difference Δh in the L * C * h color system was calculated based on the spectral reflectance measured at a light receiving angle of 75 ° and 75 °.
(2) Illuminate the metallic plate with the artificial sun lamp (Cerrick, color temperature 6500K), and observe it by changing the angle with respect to the illumination of the test plate, and change the brightness of the metallic feeling (highlight to shade) ) Was evaluated visually.
A: Excellent metal feeling.
○: There is a metallic feeling.
Δ: Poor metal feeling
X: There is no metal feeling.
(3) Saturation change depending on observation angle Illuminate the created coated plate with an artificial sun lamp (manufactured by Celic, color temperature 6500K), change the angle with respect to the illumination of the test plate, and highlight (front) to shade The saturation change to (scath) was visually evaluated.
◎: Saturation greatly increases from highlight to shade.
○: Saturation slightly increases from highlight to shade.
Δ: Saturation change from highlight to shade is poor.
X: There is no change in color saturation from highlight to shade.

The coating composition, the coating film forming method and the coating film structure of the present invention can be applied to various industrial products, particularly to the outer plate of an automobile body.

Claims (6)

A coating composition comprising a light interference pigment, a color pigment, and a multicolor glitter pigment, wherein the relationship between the interference color and the color of the color pigment in the highlight of the multicolor glitter pigment and the highlight of the light interference pigment A coating composition characterized in that the relationship between the interference color and the interference color in the highlight of the multicolor glitter pigment is a complementary color relationship. The coating composition according to claim 1, wherein the multicolor glitter pigment is scaly silica coated with a metal oxide. The coating composition according to claim 1 or 2, wherein the light interference pigment is aluminum oxide coated with a metal oxide. The coating composition according to any one of claims 1 to 3, wherein the color pigment is a transparent pigment. The coating-film formation method which coats a top clear coating material further on the coating film obtained by applying the coating composition of any one of Claims 1-4 to a base material. A coating film structure formed by the coating film forming method according to claim 5.