JP5611629B2 - Coating method - Google Patents

Description

  The present invention provides a coating color that expresses a structural color whose hue changes greatly depending on the observation angle, and has a high flip-flop property in which the brightness changes greatly depending on the observation angle, and forms a high brightness and high saturation coating film in the highlight portion. It is about the method.

  The purpose of applying the paint is to protect the material and impart aesthetics. In recent years, especially in the fields of automobile skins and home appliances, consumer demands for aesthetics have diversified, and in addition to solid paint colors that do not change the appearance of color depending on the viewing angle, use of bright pigments As a result, metallic paint colors whose color appearance changes depending on the observation angle have come to be used.

  As the metallic coating color, it is brightly colored when the coating film is observed in the vicinity of specular reflection light due to the effect of the scale-like aluminum pigment. The pearl pigments coated with metal oxides give a pearly texture that gives a grainy appearance when observed near specularly reflected light, and depending on the observation angle, may cause interference colors. Can do.

  However, in recent years, consumer demands for paint colors have diversified, and one of them is the structural color that changes greatly depending on the intensity of light hitting the coating film and the observation angle, and the flip-flop property that lightness changes greatly. There is a demand for paint colors to be included.

  Patent Document 1 relates to a method for forming a coating film having a hue appearance different from that of external light and a coated product, and an interference property containing a flake-like interference pigment made of a cholesteric liquid crystal polymer on a coating material having a plating-like gloss. A method for forming a coating to form a clear coating is described. According to this method, it is possible to obtain a coating film that exhibits a different hue between when the coating film is exposed to light and when it is shadowed, but in order to express the plating gloss, the process is complicated, Since the object to be coated is limited, there is a problem that it is difficult to apply to a wide range of uses.

JP 2004-136237 A

An object of the present invention is to provide a coating color that expresses a structural color whose hue changes greatly depending on the observation angle, and is excellent in flip-flop properties in which the brightness changes greatly depending on the observation angle, and forms a highlight, high brightness and high saturation coating film. It is to provide a forming method.

The present invention
1. A coating film forming method for coating a multicolor coating composition containing a glitter pigment and expressing a structural color on a coating film obtained by coating a metallic coating composition containing a scaly aluminum pigment on a substrate,
2. 2. The coating film formation according to item 1, wherein the glitter pigment is selected from a multi-layered scaly light interference pigment, a cholesteric liquid crystal polymer, and a scaly silica pigment coated with a metal oxide. Method,
3. 3. The coating film according to item 1 or 2, wherein the metallic coating composition contains a color pigment having the same color as the interference color in the highlight of the coating film containing the glitter pigment in the multicolor coating composition. Forming method,
4). 4. The method of forming a coating film according to any one of items 1 to 3, wherein a top clear coating is further applied in one or two layers on a coating obtained by applying a multicolor coating composition.

  The method for forming a coating film according to the present invention comprises a multicolor coating composition containing a glittering pigment expressing a structural color on a coating film obtained by coating a metallic coating composition containing a scaly aluminum pigment on a substrate. Painted, expresses a structural color whose hue changes greatly depending on the observation angle, and also has excellent flip-flop properties that change the lightness greatly depending on the observation angle, and can provide a high-brightness, high-chroma paint film with highlights In particular, it is useful in fields that require a high-grade appearance such as automobile outer panels and home appliances.

  In the coating film forming method of the present invention, the base material is a metal such as iron, zinc or aluminum, an alloy of these metals, a molded product plated or vapor-deposited with these metals, and glass, plastic or foam. A material such as a molded product by the body can be listed. A treated material obtained by subjecting these materials to a degreasing treatment or a surface treatment can also be used as a base material. Furthermore, a coating film forming material in which an undercoat coating film or an intermediate coating film is formed on the above substrate can be used as the substrate. Of these, a film-forming material is particularly preferable.

  The above-mentioned undercoat film is used to conceal the surface of the material, impart anticorrosion and rustproofness to the material, and further improve the adhesion between the intermediate coat film and topcoat film described later and the material. It is formed and can be obtained by applying and curing an undercoat. 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 surface of the material or the undercoating film, or to impart adhesion or chipping resistance. It can be obtained by applying and curing a paint. Here, the undercoat coating film may be dry-cured or uncured. The type of the 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 can be preferably used.

  In the method of the present invention, in the case of using a base coating film and / or an intermediate coating film formed as a base material, the base coating film and / or the intermediate coating film is heated and described later after crosslinking and curing. Although the metallic paint composition can be applied, the metallic paint composition can also be applied in an uncured state of the undercoating film and / or the intermediate coating film. Is also included.

  In the coating film forming method of the present invention, a metallic coating composition containing scaly aluminum pigment is applied to the substrate.

  The scaly aluminum pigment is generally produced by pulverizing and grinding aluminum in a ball mill or attritor mill using a grinding aid in the presence of a grinding fluid, and usually has an average particle size (D50) for coating. Those having a thickness of about 1 to 50 μm, particularly about 5 to 20 μm, and having a thickness in the range of 0.01 μm to 10 μm, particularly 0.1 μm to 5 μm, are suitable for the stability in the paint and the coating film to be formed. Used from the point of finishing. The average particle diameter means a long diameter. As the grinding aid, aliphatic amines, aliphatic amides and aliphatic alcohols are used in addition to higher fatty acids such as oleic acid, stearic acid, isostearic acid, lauric acid, palmitic acid and myristic acid. As the grinding fluid, aliphatic hydrocarbons such as mineral spirits are usually used.

  The scaly aluminum pigment can be roughly classified into a leafing type and a non-leafing type depending on the type of grinding aid. The leafing type is arranged (leafing) on the surface of the coating film obtained by painting when blended into the paint composition, resulting in a strong metallic finish, heat reflection, and rust prevention. Therefore, it is often used for various building materials such as tanks, ducts, piping, and roof roofing. As what is contained in the metallic coating composition in the coating film formation method of this invention, it is preferable to use a non-leafing type scaly aluminum pigment from the point of the storage stability of a coating composition.

  In the method of the present invention, the blending amount of the scaly aluminum pigment in the metallic paint composition is based on 100 parts by mass of the solid content of the resin composition to be described later, from the viewpoint of flip-flop properties and finished appearance of the obtained coating film. It is preferably in the range of 0.1 to 50 parts by mass, more preferably in the range of 0.5 to 40 parts by mass, and particularly preferably in the range of 2 to 20 parts by mass.

  The metallic paint composition can contain a color pigment. As the colored pigment, conventionally known pigments for ink and paint can be used alone or in combination of two or more. Specific examples of the color pigment include metal oxide pigments such as titanium oxide and iron oxide, composite metal oxide pigments such as titanium yellow, carbon black, azo pigments, quinacridone pigments, diketopyrrolopyrrole pigments, and perylene pigments. Pigments, perinone pigments, benzimidazolone pigments, isoindoline pigments, isoindolinone pigments, metal chelate azo pigments, phthalocyanine pigments, indanthrone pigments, dioxane pigments, indigo pigments, etc. it can. In the present invention, in particular, the use of a color pigment having the same color as the hue in the highlight of the coating film containing the glitter pigment in the multicolor coating composition described later emphasizes the structural color in the multilayer coating film, and It is preferable from the point of increasing the degree.

  In the present specification, the hue in the highlight of the glitter pigment is a color measured by the following method. Click No. For 1000 clear (trade name, manufactured by Kansai Paint Co., Ltd., nitrocellulose-modified acrylic clear paint), based on the resin solid content of 100 parts by mass, the glitter pigment is blended to be 15 parts by mass as a solid content, Dilute with a special thinner so that the viscosity is appropriate for coating and mix. Using a doctor blade, the obtained coating material is applied on a coated plate on which a black (N-2) coating film has been formed in advance so as to have a thickness of 20 μm as a cured coating film. After leaving at room temperature for 3 minutes, the coating film obtained by drying for 30 minutes in an atmosphere of 80 ° C. using a hot-air drying oven was subjected to MA-68II (trade name, manufactured by x-Rite, multi-angle spectroscopy). A hue angle h in the L * C * h color system based on the spectral reflectance received at an angle of 15 degrees from the specularly reflected light. In addition, the hue of the colored pigment refers to Aclick No. Based on the resin solid content of 100 parts by mass with respect to 1000 clear, the color pigment is blended so that the solid content is 15 parts by mass, and the paint obtained by sufficiently stirring and dispersing the viscosity is further suitable for coating. Dilute with special thinner so that Using a doctor blade, the obtained coating material is applied on a coated plate on which a gray (N-6) coating film has been formed in advance so as to have a film thickness of 20 μm as a cured coating film. After leaving at room temperature for 3 minutes, the coating film obtained by drying for 30 minutes in an atmosphere of 80 ° C. using a hot-air drying oven was subjected to MA-68II (trade name, manufactured by x-Rite, multi-angle spectroscopy). The hue angle h in the L * C * h color system based on the spectral reflectance received at an angle of 45 degrees from the regular reflection light is obtained using a photometer.

  When blending the above color pigment, the blending amount is 50 with respect to 100 parts by mass of the resin solid content in the metallic coating composition from the viewpoint of maintaining the flip-flop property of the multilayer coating film and not inhibiting the expression of the structural color. It is preferable that it is below mass part, More preferably, it exists in the range of 0.1-30 mass parts, Most preferably, it exists in the range of 0.5-10 mass parts.

  The metallic paint composition of the present invention can contain a resin component as a vehicle in addition to the scaly aluminum pigment and the colored pigment blended as necessary. The resin component is preferably a thermosetting resin composition. Specifically, for example, 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. , Urea resins, polyisocyanate compounds (including block bodies) and the like are also used in combination, and these can be used by dissolving or dispersing them in a solvent such as an organic solvent and / or water.

  Further, the metallic coating composition may contain a solvent such as water or an organic solvent, a rheology control agent, a pigment dispersant, an anti-settling agent, a curing catalyst, an antifoaming agent, a surface conditioner, an antioxidant, an ultraviolet ray as necessary. Various additives such as an absorbent and extender pigments can be appropriately blended.

  In the coating film forming method of the present invention, the metallic coating composition can be applied by a method such as electrostatic spray coating, air spraying, airless spraying, and the film thickness is 0.5 to 0.5 based on the cured coating film. The range of 30 μm is preferable from the viewpoint of the smoothness of the coating film, more preferably in the range of 5 to 25 μm, and particularly preferably in the range of 7 to 18 μm.

  In the case of spray coating, the metallic paint composition usually has a solid content of 15 to 50% by mass, preferably 20 to 40% by mass, and a viscosity at 20 ° C. of 11 to 15 seconds / in coating. It is preferable to adjust so that it becomes Ford cup # 4. The coating film itself of the metallic coating composition can be crosslinked and cured usually at a temperature of about 70 to about 150 ° C.

  In the coating film forming method of the present invention, a multicolor coating composition containing a glittering pigment and expressing a structural color can be applied onto a coating film obtained by coating and curing the metallic coating composition. You may apply this multicolor coating composition on the uncured coating film, without heat-hardening a thing.

  In the present invention, the bright pigment contained in the multicolor coating composition that expresses a structural color imparts an effect of changing the color depending on the angle of incident light or viewing angle, and has a multi-layered scaly light. Mention may be made of interference pigments and cholesteric liquid crystal polymers.

  Examples of the multi-layered scale-like light interference pigment include mica, artificial mica, glass, silica, iron oxide, aluminum oxide, aluminum, aluminum, aluminum, aluminum, etc. , Iron oxide, zinc sulfide, zinc sulfide, magnesium fluoride, aluminum fluoride, sodium fluoride, silicon oxide, aluminum oxide, thorium fluoride, chromium, etc. The pigment which formed the interference film and the pigment which laminated | stacked three or more films | membranes from which these refractive indexes differ can be mentioned.

  Multi-layered scaly interference pigments have a wavelength that is determined for a specific incident / reflecting direction because the wavelength range of the reflected light is determined by the refractive index of the materials that make up the multi-layered structure and the thickness of each layer. Since only the light is strongly reflected, a structural color whose color changes depending on the observation angle can be expressed.

  A cholesteric liquid crystal polymer is prepared by, for example, arranging a three-dimensional cross-linkable polymer such as a polyorganosiloxane having a methacryloyloxy group or an acryloyloxy group in the side chain and a liquid crystal substance into a parallel layer and then spiraling the molecules. In order to make a structure, the layers are stacked in layers so that the molecular orientation is slightly different depending on the electric field or magnetic field, the molecules oriented by the polymerization reaction are fixed, the thin film layer is three-dimensionally cross-linked, and then separated from the substrate. What was obtained by grind | pulverizing to a desired particle size can be mentioned.

  Since the cholesteric liquid crystal polymer has a helical structure, the wavelength range of light reflected is determined by the pitch width of the helical structure and the refractive index of the liquid crystal, and the reflected light of a specific range of wavelengths has a pitch corresponding to the light wavelength. The light component is split into a spiral structure and becomes a reflection component and a transmission component according to the direction of rotation of the spiral. Since the spiral pitch varies depending on the observation angle, a structural color that changes color appears.

  In the present invention, the glitter pigment preferably has a longitudinal average particle diameter (D50) in the range of 1 to 50 μm, preferably in the range of 3 to 30 μm, from the viewpoint of the finish of the coating film. It is more preferable to use a thing, and it is especially preferable to use a thing within the range of 5-25 micrometers. Moreover, it is preferable to use the thing within the range of 0.01 micrometer-10 micrometers, and it is especially preferable to use the thing within the range of 0.1 micrometer-5 micrometers.

  The content of the glitter pigment is from the viewpoint of maintaining a metallic feeling and developing a structural color in the multilayer coating film to a solid content of 100 parts by mass of the resin composition in the multicolor coating composition. It is preferably in the range of 1 to 50 parts by mass, more preferably in the range of 0.5 to 40 parts by mass, and particularly preferably in the range of 2 to 20 parts by mass.

  The multi-color coating composition in the present invention can contain a color pigment. As the colored pigment, conventionally known pigments for ink and paint can be used alone or in combination of two or more. Specific examples of the color pigments include those listed as those that can be incorporated into the metallic paint composition, and, like the metallic paint composition, the glitter in the multicolor paint composition. It is preferable to use a color pigment having the same color as the hue in the highlight of the coating film containing the pigment from the viewpoint of enhancing the expression of the structural color and increasing the saturation in the multilayer coating film.

  When blending the above-mentioned color pigment, the blending amount maintains the flip-flop property of the multilayer coating film, and does not inhibit the expression of the structural color, based on 100 parts by mass of the resin solid content in the multi-color coating composition, The amount is preferably 50 parts by mass or less, more preferably in the range of 0.1 to 30 parts by mass, and particularly preferably in the range of 0.5 to 10 parts by mass.

  The multi-color coating composition of the present invention can contain a resin component as a vehicle in addition to a glitter pigment that expresses a structural color and a colored pigment that is blended as necessary. As a resin component, what was mentioned as what can be mix | blended with the said metallic paint composition can be used.

  Furthermore, in the multi-color coating composition, if necessary, a solvent such as water or an organic solvent, a rheology control agent, a pigment dispersant, an anti-settling agent, a curing catalyst, an antifoaming agent, a surface conditioner, an antioxidant, Various additives such as ultraviolet absorbers and extender pigments can be appropriately blended.

  The multicolor coating composition in the method of the present invention can be prepared by mixing and dispersing the aforementioned components.

  In the coating film forming method of the present invention, the multicolor coating composition can be applied by a method such as electrostatic spray coating, air spraying, airless spraying, and the film thickness is 0.5 based on the cured coating film. The range of ˜30 μm is preferable from the viewpoint of the smoothness of the coating film, more preferably in the range of 5-25 μm, and particularly preferably in the range of 7-18 μm.

  The multi-color coating composition of the present invention preferably has a light transmittance in the visible light region of 40% or more, more preferably from the viewpoint of achieving both flip-flop properties and expression of structural color in the multilayer coating film. 50% or more. Specifically, the light transmittance of the coating film is a spectrophotometer “MPS” obtained by coating a smooth PTFE plate so as to be 30 μm as a cured coating film, drying and curing, and then peeling off. -2450 "(trade name: manufactured by Shimadzu Corporation) is an average value of light transmittance in a visible light region (wavelength: 400 nm to 700 nm). The light transmittance in the visible light region is a ratio of transmitting visible light rays, and means that the larger the numerical value, the higher the transparency.

  In the case of spray coating, the multi-color coating composition usually has a solid content of 15 to 50% by mass, preferably 20 to 40% by mass, and a viscosity at 20 ° C. of 11 to 15 seconds. / It is preferable to adjust so that it becomes Ford Cup # 4. The coating film itself of the multicolor coating composition can be crosslinked and cured usually at a temperature of about 70 to about 150 ° C.

  In the present invention, a top clear coating can be formed by further coating one or more top clear coatings on the coating obtained by applying the multicolor coating composition.

  In the method of the present invention, the top clear paint described later can be applied on the coating film obtained by applying and curing the multi-color coating composition, but the multi-color coating composition can be applied in an uncured state without being cured by heating. A top clear paint can be applied on the film. The coating of the multicolor coating composition itself can be cured and dried at a temperature of about 70 to about 150 ° C.

  As the top clear coating material 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. Moreover, additives, such as solvents, such as water and an organic solvent, a curing catalyst, an antifoamer, and a ultraviolet absorber, can be suitably mix | blended as needed.

  As the top clear paint in the present invention, a color clear paint containing a color pigment and / or a dye can be used as long as transparency is not impaired. As the color pigments and dyes, those known in the art for inks and paints can be used alone or in combination of two or more. The addition amount may be appropriately determined, but is preferably 30 parts by mass or less, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the vehicle-forming resin composition in the top clear coating. Within range.

  In the present invention, when two or more layers of the top clear paint are applied, the color clear paint can be applied to the first layer.

  The top clear coating in the present invention can be applied by a method such as electrostatic coating, air spray, airless spray, and the film thickness is preferably in the range of 5 to 40 μm based on the cured coating film.

  In the present invention, when the top clear paint is applied without heating and curing the metallic paint composition and / or the multi-color paint composition, the top clear paint is applied and then these paints are simultaneously heat cured. Can do. The top clear coating film itself can be crosslinked and cured at a temperature of about 70 to about 150 ° C.

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 dropped into the reaction vessel over 1 hour and aged for 1 hour, and then cooled to 30 ° C. while gradually adding 40 parts by mass of a 5% dimethylethanolamine aqueous solution to the reaction vessel. , While filtering through a 100 mesh nylon cloth, discharging with an average particle size of 100 nm (submicron particle size distribution measuring device “COULTER N4 type” (manufactured by Beckman Coulter), 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. Thereafter, the temperature of the obtained condensation reaction product was lowered to 170 ° C., and 38.3 parts by weight of trimellitic anhydride was further added to add a carboxyl group, and the mixture was reacted at 170 ° C. for 30 minutes. Dilution with ethyl-1-hexanol gave a polyester resin solution with a solid content of 70%. 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 Polyester resin obtained in Production Example 3 in 225 ml of mayonnaise bottle with 7.4 parts of Heliogen Green L8730 (trade name, chlorinated copper phthalocyanine green pigment, manufactured by BASF) 53 parts of the solution and 50 parts of deionized water were added, and 130 parts of 1.5 mm diameter 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 zirconia beads to obtain a colored pigment dispersion.
(Production Example 5) Preparation of scaly aluminum pigment liquid In a stainless steel beaker, aluminum paste GX-180 (trade name, scaly aluminum pigment paste, solid content 74% by mass, average particle size 16.9 μm, manufactured by Asahi Kasei Metals Co., Ltd. ) 135 parts and 95 parts by mass of ethylene glycol monobutyl ether were mixed with stirring to obtain a high-concentration bright pigment liquid 1.
(Production Example 6) Preparation of multicolor glitter pigment liquid In a stainless steel beaker, 100 parts of Helicone HC Scalaveus (trade name, cholesteric liquid crystal polymer, color change from highlight green to shade blue), manufactured by Wacker, Inc. 130 parts of ethylene glycol monobutyl ether was stirred and mixed to obtain a multicolor glitter pigment liquid.
(Measurement of highlight color of multi-color pigment and color of colored pigment)
The highlight color and the color pigment color of the multicolor glitter pigment used in the examples and comparative examples were measured in the following manner, and the results are shown in Table 1.

  The highlight color of the multi-color glitter pigment is Aclick No. 1000 clear (trade name, manufactured by Kansai Paint Co., Ltd., nitrocellulose-modified acrylic clear paint), based on 100 parts by mass of the resin solid content, blending the glitter pigment to a solid content of 15 parts by mass Then, dilute with a special thinner so that the viscosity is appropriate. Using a doctor blade, the obtained coating material is applied on a coated plate on which a black (N-2) coating film has been formed in advance so as to have a cured coating film thickness of 20 μm. After leaving at room temperature for 3 minutes, the coating film obtained by drying for 30 minutes in an atmosphere of 80 ° C. using a hot-air drying oven was subjected to MA-68II (trade name, manufactured by x-Rite, multi-angle spectroscopy). Using a photometer, MA-68II (trade name, multi-angle spectrophotometer) manufactured by X-Rite was used to obtain a spectral reflectance that was received at 15 ° with respect to specular reflection light. The hue angle h in the L * C * h color system measured based on this was shown.

  The color of the color pigment is specifically referred to as Aclick No. Based on 100 parts by mass of the resin solid content with respect to 1000 clear, the color pigment is blended so as to be 15 parts by mass as solid content, and the paint obtained by sufficiently stirring and dispersing further has a viscosity suitable for coating. The resulting paint is diluted with a special thinner so that the cured coating film is applied to a thickness of 20 μm on a coating plate on which a gray (N-6) coating film has been formed in advance using a doctor blade. After leaving at room temperature for 3 minutes, the coating film obtained by drying using a hot air drying oven was subjected to specular reflection using MA-68II (trade name) manufactured by X-Rite. The hue angle h in the L * C * h color system measured based on the spectral reflectance received at 45 ° is shown.

(Production Examples 7 to 10) Preparation of metallic paints 1 to 4 75 parts of the 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) Per 100 parts (solid content) of the resin component, the luster pigment (flaky aluminum pigment) and the colored pigment are blended in the ratios shown in Table 2, mixed with stirring, diluted to a viscosity suitable for coating, and solid content of about 25 % Metallic paints 1 to 3 (organic solvent-type paints) were prepared.

(Production Examples 11 to 16) Preparation of multi-color paints 1 to 6
Per 100 parts (solid content) of a resin component comprising 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) A scaly aluminum pigment, a multicolor glitter pigment) and a color pigment are blended in the ratios shown in Table 2, mixed with stirring, diluted to an appropriate viscosity for coating, and multicolor paints 1 to 6 having a solid content of about 25%. (Organic solvent type paint) was prepared.

(Production Example 17) Preparation of metallic paint 5 100 parts of the acrylic resin emulsion obtained in Production Example 2, 50 parts of the polyester resin solution obtained in Production Example 3, and 14. the color pigment dispersion obtained in Production Example 5. 9 parts, 34.6 parts of the scaly aluminum pigment solution obtained in Production Example 5 and 37.5 parts of Cymel 325 (trade name, manufactured by Nippon Cytec Industries, Inc., melamine resin, solid content 80%) were mixed uniformly. Furthermore, Primal ASE-60 (trade name, manufactured by Rohm and Haas Co., polyacrylic acid-based thickener), 2- (dimethylamino) ethanol and deionized water were added to adjust the pH to 8.0, paint solids content 25%, Ford Cup No. 20 at 20 ° C. 4 was used to prepare a metallic paint 7 having a viscosity of 40 seconds.

  The ratio of the scaly aluminum pigment and the colored pigment of the metallic paint 7 is the same as that of the metallic paint 2.

(Production Example 18) Preparation of multi-color paint 7 100 parts of the acrylic resin emulsion obtained in Production Example 2, 56.4 parts of the polyester resin solution obtained in Production Example 3, and the color pigment dispersion obtained in Production Example 5 1.5 parts, 11.5 parts of the multi-color glitter pigment liquid obtained in Production Example 7 and 37.5 parts of Cymel 325 (trade name, manufactured by Nippon Cytec Industries, Inc., melamine resin, solid content 80%) Mix uniformly, and add Primal ASE-60 (trade name, manufactured by Rohm and Haas, polyacrylic acid thickener), 2- (dimethylamino) ethanol and deionized water to pH 8.0, paint solids Ford Cup No. 25% at 20 ° C. 4 was used to prepare a multicolor paint 8 having a viscosity of 40 seconds.

The ratio of the multicolor glitter pigment and the color pigment of the multicolor paint 7 is the same as that of the multicolor paint 2.
(Measurement of light transmittance in the visible light region of the coating obtained by applying multi-color paint)
The light transmittance in the visible light region of the coating obtained by applying the multi-color paints 1 to 7 was measured in the following manner, and the results are shown in Table 3.

  Using a doctor blade on a smooth PTFE plate with a multi-color paint 1-7 as a cured coating to a thickness of 30 μm, leave it at room temperature for 15 minutes, then use a hot air dryer The coating film obtained after being cured and dried for 30 minutes in an atmosphere and then peeled off was exposed to light in the visible light region (wavelength 400 nm to 700 nm) with a spectrophotometer “MPS-2450” (trade name: manufactured by Shimadzu Corporation). The transmittance was measured.

Examples 1-7, Comparative Examples 1-3
(Creation of test plate)
Cationic electrodeposition paint “ELECRON 9400HB” (trade name: manufactured by Kansai Paint Co., Ltd., epoxy resin polyamine-based cation resin) on steel plate (JISG3141, size 400 × 300 × 0.8 mm) subjected to adjustment degreasing and zinc phosphate treatment (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.
A test plate was prepared by applying a metallic paint and multi-color paint to the base material prepared in the coating (1) in the steps shown in Table 4 and applying a top clear paint in the following manner.

Using a REA gun, apply a metallic paint as a cured coating to a thickness of 10 μm under the conditions of a boot temperature of 25 ° C. and a humidity of 75%, and leave it at room temperature for 15 minutes. The coated film was coated to a thickness of 10 μm under the conditions of a boot temperature of 25 ° C. and a humidity of 75%, and then a clear paint (Lugabe Kukuriya, manufactured by Kansai Paint Co., Ltd. Name, acrylic resin / amino resin type, organic solvent type) using a mini-bell type rotary electrostatic coating machine, so that the cured coating film is 25 to 35 μm under the conditions of a boot temperature of 25 ° C. and a humidity of 75%. Painted on. 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. For Comparative Examples 1 to 3, the substrate was coated with a metallic paint or multi-color paint as a cured coating film in the same manner as described above so as to have a thickness of 15 μm, and then the top clear paint was applied in the same manner, followed by curing and drying. A board was created.
(Evaluation of design properties)
The design properties of the test plate were evaluated in the following manner, and the results are shown in Table 4.

(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.
5: Hue change is remarkable.
4: The hue change is large.
3: There is a hue change.
2: Little change in hue.
1: There is no hue change.
(2) Flip-flop visual observation: The prepared coated plate is illuminated with an artificial sun lamp (manufactured by Celic, color temperature 6500K), and observed at different angles with respect to the illumination of the test plate. The change in brightness was evaluated visually.
4: The brightness change is large.
3: There is a change in brightness.
2: Little change in brightness.
1: No change in brightness.
FF value: XYZ based on the spectral reflectance measured using the MA-68II (trade name) manufactured by X-Rite at the light receiving angles of 15 ° and 45 ° with respect to the regular reflection light. The Y value in the color system was calculated, and the following calculation was further performed based on the calculated value.
FF value = 2 * (15Y−45Y) / (15Y + 45Y)
15Y: Y value calculated based on the spectral reflectance of 15 °
45Y: Y value calculated based on the spectral reflectance of 45 ° (3) Using the MA-68II (trade name) manufactured by X-Rite, the specular reflection of the highlight lightness and highlight saturation was made. Based on the spectral reflectance measured at a light receiving angle of 15 ° with respect to light, the lightness L * and chroma C * in the L * a * b * color system were calculated. Furthermore, saturation efficiency was calculated by dividing saturation by brightness.

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

Claims (2)

A scaly silica pigment coated with a multilayered scaly light-interfering pigment, a cholesteric liquid crystal polymer, and a metal oxide on a coating film obtained by coating a metallic coating composition containing a scaly aluminum pigment on a substrate. A coating film forming method for applying a multi-color coating composition containing a glittering pigment selected from the group consisting of a glittering pigment , wherein the metallic coating composition contains the glittering pigment in the multi-color coating composition A method of forming a coating film comprising a coloring pigment having a color similar to the interference color in the highlight of the above . 2. The method of forming a coating film according to claim 1, wherein a top clear coating is further applied in one or two layers on the coating obtained by applying the multi-color coating composition .