JP2011162732A - Metallic paint composition and method of forming paint film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metallic paint composition applicable to various industrial products, especially outer plate of a car, capable of forming a paint film generally high in brightness, generating coherent color and delicate hue change in highlight (near specular reflection light) and capable of perceiving whiteness in shade (oblique direction), and to provide a method of forming a paint film capable of forming a paint film. <P>SOLUTION: The metallic paint composition includes a scale-like aluminum pigment and a scale-like coherent pigment. The IV value of the scale-like aluminum pigment in forming paint film is not smaller than 100 and not greater than 200. The scale-like coherent pigment is prepared by coating titanium oxide on a translucent scale-like base material and the scale-like base material is an artificial mica or a silica flake. A method of forming a paint film in which the paint composition is coated on a base material and a clear paint is coated further is also disclosed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention is a metallic material capable of forming a coating film capable of producing a subtle hue change by producing interference colors in highlights (near specular reflection light) and giving subtle changes in hue in the shade (oblique direction). The present invention relates to a coating composition and a coating film forming method.

In industrial products such as automobiles, white pearl coating colors that exhibit interference colors in highlights (near specularly reflected light) and slightly change hue are popular as coating colors that have both a high-class feeling and a clean feeling. As a method for obtaining a white pearl-based paint color, a multi-layer coating is applied in which a metallic base paint containing an interfering scaly glitter pigment is applied on a paint film of a white base paint, and further a clear paint is applied. A film forming method is known. In the coating film obtained by this method, the color changes depending on the observation angle due to the interference glittering pigment contained in the metallic base coating, but the white base coating, metallic base coating and clear coating It is necessary to laminate three layers of coating. Moreover, since the concealing power of the metallic base coating film containing scaly glittering pigment is insufficient, there is a problem that the white base coating film is limited to one having high brightness.

  As a method for obtaining a white pearl-based coating color as a two-layer coating film, a multilayer coating film in which a coating composition containing an interference scale-like glitter pigment and a scale-like aluminum pigment is applied, and further a clear paint is applied. Formation methods are known. In this case, depending on the type of scaly aluminum pigment, there are problems in that the expression of the interference color is weak in the highlight and the brightness of the shade is lowered.

  Patent Document 1 is an application relating to a coating composition that has a transparent feeling, expresses a strong brightness, and is excellent in concealment, and includes a vehicle, a metal oxide-coated alumina flake pigment, an aluminum flake pigment, or a particulate titanium dioxide pigment. A coating composition containing is disclosed. Although the coating film by the coating composition disclosed by patent document 1 expresses the strong particle feeling by a metal oxide coat | covered alumina flake pigment in highlight, only the coating film with low brightness and the interference effect in highlight is weak. There was a problem that it could not be obtained.

JP 2000-86945 A

The object of the present invention is to provide a coating film that has high brightness overall, expresses interference colors in highlights (near specularly reflected light), produces subtle hue changes, and can perceive whiteness in shades (diagonal directions). The object is to provide a formable metallic coating composition and a method for forming a coating film.

The present invention
1. A metallic paint composition comprising a scaly aluminum pigment and a scaly interference pigment, wherein the scaly aluminum pigment has a IV value of 100 or more and 250 or less when a coating film is formed,
2. 2. The metallic paint composition according to 1, wherein the scaly interference pigment is a translucent scaly substrate coated with titanium oxide, and the scaly substrate is artificial mica or silica flakes,
3. Item 3 or 2 wherein the content of the scaly aluminum pigment is in the range of 0.1 to 25 parts by mass as the solid content with respect to 100 parts by mass of the resin solid content that is a vehicle forming component in the coating composition. Metallic paint composition,
4). 4. The metallic paint composition according to 1 to 3, wherein the mass ratio of the scaly aluminum pigment to the scaly interference pigment is within the range of 1/1 to 1/6 in the former / latter ratio. A method for forming a coating film, wherein a metallic coating composition described in the items 1 to 4 is applied to a substrate, and further a clear coating is applied.
6). It is related with the coating-film formation method of 5 with which the lightness L * in the L * a * b * color system of a base material exists in the range of 40-90.

According to the present invention, there is provided a coating film which has high brightness as a whole, produces an interference color in highlights (near specularly reflected light) and produces a subtle hue change, and can perceive whiteness in a shade (oblique direction). A formable metallic coating composition and a coating film forming method can be obtained.

The metallic paint composition of the present invention is a scaly form having an IV value of 100 or more and 250 or less when a coating film is formed for the purpose of expressing interference color and concealing in highlights of a coating film obtained by coating. Contains aluminum pigment.

  The scaly aluminum pigment is generally produced by grinding and grinding aluminum in a ball mill or attritor mill using a grinding aid in the presence of a grinding fluid. 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. Aliphatic hydrocarbons such as mineral spirits are used as the grinding fluid.

  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. In the coating composition of the present invention, it is preferable to use a non-leafing type scaly aluminum pigment from the viewpoint of the whiteness of the highlight of the coating film obtained by coating.

  In the metallic paint composition of the present invention, the scaly aluminum pigment having an IV value of 100 to 250 when a coating film is formed is used. The scale-like aluminum pigment in the metallic paint composition of the present invention preferably has an IV value in the range of 110 to 240 in terms of expressing interference colors in highlights, and more preferably in the range of 120 to 230. is there. The IV value is an abbreviation for Intensity Value, and is a numerical value indicating the luminance in highlight. The smaller the numerical value, the darker the value. The IV value can be measured using a multi-angle spectrophotometer or a colorimeter that can change the light irradiation angle and the light receiving angle. In this specification, the scaly aluminum is formed when a coating film is formed. The IV value of the pigment is defined by a numerical value obtained by measuring a coated plate obtained by the following procedure using “Alcorp LMR-200H” manufactured by Kansai Paint Co., Ltd.

  The IV value of the flaky aluminum pigment when the coating film is formed varies depending on the orientation of the flaky aluminum pigment after the coating film is formed. Therefore, it varies depending on the coating film forming component and the coating conditions. The coating plate preparation method for measuring IV value of the scaly aluminum pigment in this specification is shown.

  Ethylene glycol monobutyl ether is added to the scaly aluminum pigment to be measured in advance and stirred to prepare a high-concentration scaly aluminum pigment solution having a solid content of 50% by mass. The hydroxyl group-containing acrylic resin solution obtained in Production Example 1 is used as the solid content. 75 parts of Uban 28-60 (trade name, butyl etherified melamine resin, manufactured by Mitsui Chemicals Co., Ltd.) with respect to 100 parts by mass of resin solids, which is a vehicle-forming component consisting of 25 parts, It added so that solid content might be 15 mass parts, and also the organic solvent was added, and it stirred and mixed, and prepared the coating material of the viscosity in 20 degreeC for 20 second / forward cup # 3. The obtained paint was air atomized electrostatically coated to a thickness of 20 μm as a cured coating on a solvent-degreased steel plate on which an N-6 gray color intermediate coating was previously formed, and an experiment at room temperature of about 20 ° C. After leaving it in the room for 5 minutes, the clear paint “Lugabe Kukuriya” (trade name, manufactured by Kansai Paint, acrylic resin / amino resin type, organic solvent type) is used with a minibell type rotary electrostatic coating machine. The cured coating film was coated to a thickness of 30 μm under the conditions of a boot temperature of 25 ° C. and a humidity of 75%. After coating, the sample is 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 dry and cure the multilayer coating film at the same time to prepare a coated plate for measurement.

  The IV value of the obtained coated plate was measured using “Alcoop LMR-200H” manufactured by Kansai Paint Co., Ltd. Specifically, the light intensity IV value obtained by receiving the reflected light from the laser light source irradiated at an incident angle of 45 degrees with a light receiver having an angle of 10 degrees with respect to the regular reflected light is obtained.

  In the metallic coating composition of the present invention, when the IV value of the scaly aluminum pigment when the coating film is formed exceeds 250, the highlight brightness of the multilayer coating film becomes too high, and the scaly interference described later. There arises a problem of inhibiting the expression of interference colors by the pigment, and when the IV value is less than 100, there is a problem that the brightness of the highlight is insufficient.

  The scale-like aluminum pigment preferably has an average particle size in the range of 5 to 30 μm from the viewpoint of the finish of the coated film and the brightness of the highlight, more preferably the particle size. The diameter is in the range of 7 to 25 μm, particularly preferably in the range of 8 to 23 μm. It is preferable to use a thickness in the range of 0.05 to 0.5 μm. The particle size and thickness here means a numerical value obtained by observing the scaly aluminum pigment with an optical microscope or an electron microscope, or a numerical value measured with a particle size distribution measuring apparatus using a laser such as a laser diffraction method. To do.

  In addition, the content of the scaly aluminum pigment is within the range of 0.1 to 25 parts by mass in total with respect to 100 parts by mass of the resin solid content in the paint from the point of finish of the coating film obtained by coating. Is preferable, more preferably in the range of 0.3 to 20 parts by mass, and particularly preferably in the range of 0.5 to 20 parts by mass.

  The metallic paint composition of the present invention has a scaly interference pigment for the purpose of producing an interference color and causing a subtle hue change in the highlight (near specular reflection light) of a coating film obtained by painting. contains.

The scale-like interference pigment is a pigment in which a semi-transparent scale-like substrate is coated with a metal oxide, and generates an interference color depending on the type of the coated metal oxide and the thickness of the coating layer. As the translucent substrate, those using mica, artificial mica, glass, silica and aluminum oxide are known, and as the metal oxide to be coated, titanium oxide and iron oxide are known. The scaly interference pigment to be included in the coating composition of the present invention is not particularly limited, but silica flakes or artificial mica are used from the viewpoint of highlight interference color expression in the multilayer coating film and whiteness in the shade. It is preferable to use a base material coated with titanium oxide. Artificial mica is synthesized by heating industrial raw materials such as SiO ₂ , MgO, Al ₂ O ₃ , K ₂ SiF ₆ , Na ₂ SiF ₆ , melting at a high temperature of about 1500 ° C., and cooling to crystallize. Compared with natural mica, it has less impurities and has a uniform size and thickness. Specifically, fluorine phlogopite mica (KMg ₃ AlSi ₃ O ₁₀ F ₂ ), potassium tetrasilicon mica (KMg ₂₅ AlSi ₄ O ₁₀ F ₂ ), sodium tetrasilicon mica (NaMg ₂₅ AlSi ₄ O ₁₀ F ₂ ), Na Teniolite (NaMg ₂ LiSi ₄ O ₁₀ F ₂ ), LiNa teniolite (LiMg ₂ LiSi ₄ O ₁₀ F ₂ ) and the like are known.

  The scale-like interference pigment preferably has an average particle size in the range of 3 to 40 μm from the viewpoint of the finish of the coated film and the brightness of the highlight, more preferably the particle size. The diameter is in the range of 5 to 30 μm, particularly preferably in the range of 6 to 25 μm. It is preferable to use a thickness in the range of 0.05 to 0.5 μm. The particle size and thickness here means a numerical value obtained by observing the scaly interference pigment with an optical microscope or an electron microscope, or a numerical value measured with a particle size distribution measuring apparatus using a laser such as a laser diffraction method. To do.

  Further, the content of the scaly interference pigment is within the range of 0.1 to 25 parts by mass in total with respect to 100 parts by mass of the resin solid content in the paint from the point of finish of the coating film obtained by coating. Is preferable, more preferably in the range of 0.3 to 23 parts by mass, and particularly preferably in the range of 0.5 to 20 parts by mass.

  In the metallic paint composition of the present invention, the total content of the scaly aluminum pigment and the scaly interference pigment is based on 100 parts by mass of the resin solid content in the paint from the viewpoint of the finish of the coating film. It is preferably within the range of 0.2 to 35 parts by mass, more preferably within the range of 0.5 to 30 parts by mass, and particularly preferably within the range of 1 to 25 parts by mass.

  Further, the ratio of the content of the scaly aluminum pigment to the scaly interference pigment is preferably such that the content of the scaly interference pigment is equal to or more than that of the scaly aluminum pigment. The mass ratio of the aluminum pigment to the scaly interference pigment is preferably within a range of 1/1 to 1/6 from the viewpoint of highlight whiteness and interference color expression.

  The metallic paint composition of the present invention can contain a color pigment for the purpose of finely adjusting the hue within a range in which the whiteness of the coating film obtained by coating can be maintained. The coloring pigment is not particularly limited, and specifically, inorganic pigments such as transparent iron oxide pigments, complex oxide pigments such as titanium yellow, azo pigments, quinacridone pigments, diketopyrrolopyrrole. Pigments, perylene pigments, perinone pigments, benzimidazolone pigments, isoindoline pigments, isoindolinone pigments, metal chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, dioxazine pigments, selenium pigments, Any one or more of organic pigments such as indigo pigments and carbon black pigments can be used in combination.

  When the color pigment is blended in the metallic paint composition of the present invention, the content is 0.01 to 30 parts by mass with respect to 100 parts by mass of the resin solid content in the paint from the point of whiteness in the highlight of the coating film. It is preferable to be within the range, more preferably 0.1 to 25 parts by mass, particularly preferably 0.2 to 20 parts by mass.

  The metallic coating composition of the present invention can usually contain a resin component as a vehicle. Specific examples of the resin component include base resins such as acrylic resins, polyester resins, alkyd resins, and urethane resins having a crosslinkable functional group such as a hydroxyl group, melamine resins, urea resins, polyisocyanate compounds (block bodies). In combination with a crosslinking agent such as an organic solvent and / or a solvent such as water.

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

  The metallic coating composition of the present invention is prepared by mixing and dispersing the aforementioned components. The solid content at the time of coating is adjusted to 12 to 60% by mass, preferably 15 to 50% 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.

  Next, the coating film forming method of the present invention will be described. In the coating film forming method of the present invention, the metallic coating composition as described above is applied to a substrate, and a clear coating is applied to the obtained coating film.

  Base materials include metals such as iron, zinc, aluminum and magnesium, alloys containing these, molded products plated or vapor-deposited with these metals, and molded products made of glass, plastic, foam, etc. Can be mentioned. Furthermore, the base material can be appropriately subjected to degreasing treatment or surface treatment according to these materials. 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 surface of the material or the undercoat film, to provide adhesion or chipping resistance, or to adjust the lightness of the multilayer coating film. It can be obtained by applying an intermediate coating on the surface of the material or undercoat, 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 particular, when an undercoat film or an intermediate coat film is formed as a substrate, the above-mentioned metallic paint composition can be applied after the undercoat film and the intermediate coat film are heated and crosslinked and cured. Alternatively, the undercoat coating film is heated to form an intermediate coating film after crosslinking and curing, and the above-described metallic coating composition or a color base coating described later can be applied in an uncured state of the intermediate coating film. Or you may apply the above-mentioned metallic coating composition or the color base coating mentioned later in the state in which the undercoat coating film and the intermediate coating film are uncured.

  In the coating film forming method of the present invention, the lightness L * in the L * a * b * color system of the substrate can be set within the range of 40 to 90. The L * a * b * color system is a color system defined by the International Lighting Commission in 1976 and adopted in JIS Z 8729, and L * is a numerical value representing lightness. The lightness can be measured using a multi-angle spectrophotometer or a colorimeter that can change the light irradiation angle and the light receiving angle. In this specification, the lightness L * is a dry-cured coating. When MA-68II (trade name, multi-angle spectrophotometer, manufactured by x-rite) is used for the film, and light irradiated from 45 degrees to the coating film is received at an angle of 45 degrees from the regular reflection light It is a numerical value obtained by calculating from the spectral reflectance.

  When the coating film having the lightness L * of 40 or more is used as a base material, the lightness of the intermediate coating film can be adjusted. A color base coating described later is formed on the undercoating film and / or the intermediate coating film. A coating film obtained by painting may be used as a base material.

  The color base paint contains a titanium oxide pigment as a coloring material. Titanium oxide pigments are widely used as white pigments in the paint field because of their high refractive index, and there are rutile and anatase types depending on the crystal form, and any of these may be used in the present invention. From the viewpoint of weather resistance, a rutile type can be used. Moreover, you may use what processed the surface with inorganic compounds, such as a silica, a zirconium oxide, and aluminum oxide, for the purpose of improving a dispersibility and a weather resistance. From the viewpoint of hiding power, it is preferable to use those having a primary particle diameter in the range of 100 to 400 nm, and more preferably in the range of 200 to 300 nm.

  The content of the titanium oxide pigment in the color base paint is preferably from 30 to 250 parts by weight, particularly preferably from 100 parts by weight of resin solids, which is a vehicle forming component described later, from the viewpoint of concealability and finish. It is 50-120 mass parts.

  In addition to the titanium oxide pigment, a color pigment can be blended in the color base paint for the purpose of adjusting the hue and brightness of the multilayer coating film. The coloring pigment is not particularly limited, and specifically, inorganic pigments such as transparent iron oxide pigments, complex oxide pigments such as titanium yellow, azo pigments, quinacridone pigments, diketopyrrolopyrrole. Pigments, perylene pigments, perinone pigments, benzimidazolone pigments, isoindoline pigments, isoindolinone pigments, metal chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, dioxazine pigments, selenium pigments, Any one or more of organic pigments such as indigo pigments and carbon black pigments can be used in combination.

  In the present invention, when a color pigment is blended in the color base paint, the content thereof is within the range of 0.01 to 30 parts by mass with respect to 100 parts by mass of the resin solid content from the point of brightness of the multilayer coating film. More preferably, it is preferably in the range of 0.02 to 25 parts by mass.

  The color base paint can usually contain a resin component as a vehicle. Specific examples of the resin component include base resins such as acrylic resins, polyester resins, alkyd resins, and urethane resins having a crosslinkable functional group such as a hydroxyl group, and melamine resins, urea resins, and polyisocyanate compounds as necessary. Examples include those used in combination with a crosslinking agent such as (including a block body), 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 water or organic solvents, pigment dispersants, anti-settling agents, curing catalysts, antifoaming agents, antioxidants, UV absorbers, rheology control agents, etc., are added to the color base paint as necessary. An agent, extender, etc. can be appropriately blended.

  The color base paint can be applied by electrostatic coating, air spraying, airless spraying, etc., and its film thickness is in the range of 5 to 100 μm based on the cured coating film, which conceals the substrate. It is preferable from the point of the smoothness of a coating film, More preferably, it exists in the range of 10-70 micrometers. In the case of a baked and dried type, the color base coating film can usually be crosslinked and cured at a temperature of about 50 to about 180 ° C., and in the case of a room temperature drying type or a forced drying type, it is usually room temperature drying to about about It can be crosslinked and cured at a temperature of 80 ° C.

  In the method for forming a coating film according to the present invention, when a coating film made of a color base paint is used as a base material, the color base coating material can be heated and crosslinked and cured to form a base material. It is good also as a base material in the state of hardening.

  The metallic paint composition of the present invention can be applied to the above-mentioned various substrates by methods such as electrostatic coating, air spraying, airless spraying, and the film thickness is in the range of 5 to 30 μm based on the cured coating film. It is preferable from the viewpoint of the smoothness of the coating film. Usually, it can be heated and dried and cured after being applied to a predetermined film thickness, but a clear paint described later can be applied in an uncured state. The coating film itself of the metallic coating composition of the present invention can be crosslinked and cured usually at a temperature of about 50 to about 180 ° C. in the case of a baking dry type, and in the case of a room temperature drying type or a forced drying type, Usually, it can be cured at a temperature of from room temperature to about 80 ° C.

  The clear coating in the method of the present invention is a coating to be applied to the uncured or cured coating surface of the above-mentioned metallic coating composition, which is mainly composed of a resin component and a solvent, and, if necessary, other coating additives. It is a liquid paint that forms a colorless or colored transparent coating film by blending an agent or the like.

As the clear paint in the method of the present invention, conventionally known clear paints 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.

In the clear paint in the method of the present invention, a color pigment can be blended in a timely manner as long as transparency is not impaired. 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 as a solid content with respect to 100 parts by mass of the resin solid content in the clear coating film.
It is within a range of not more than mass parts, preferably 0.01 to 15 mass parts, particularly preferably 0.1 to 10 mass parts.

  The clear coating in the method of 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 15 to 70 μm based on the cured coating film. The clear coating film itself can be crosslinked and cured usually at a temperature of about 50 to about 180 ° C. in the case of a baking dry type, and usually in the case of a normal temperature drying type or a forced drying type. It can be crosslinked and cured at a temperature of about 80 ° 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.
(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 composed of 10 parts of ethylene glycol monoethyl ether acetate and 0.6 part of 2,2′-azobis (2-methylpropionitrile) was dropped into a reaction vessel maintained at 135 ° C. over 1 hour 30 minutes. Aged for another 2 hours. Next, ethylene glycol monoethyl ether acetate was distilled off under reduced pressure to obtain a hydroxyl group-containing acrylic resin solution having a resin solid content of 65% by mass. The obtained hydroxyl group-containing resin had a hydroxyl value of 54 mgKOH / g and a number average molecular weight of 20,000. 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).

(IV value measurement of scaly aluminum pigment when coating film is formed)
The IV values of the scaly aluminum pigments when formed into a coating film to be blended with the metallic paint compositions of Examples and Comparative Examples were measured in the following manner, and the results are shown outside Table 1. Ethylene glycol monobutyl ether is added to the scaly aluminum pigment to be measured in advance and stirred to prepare a high-concentration scaly aluminum pigment solution having a solid content of 50% by mass. The hydroxyl group-containing acrylic resin solution obtained in Production Example 1 is used as the solid content. 75 parts of Uban 28-60 (trade name, butyl etherified melamine resin, manufactured by Mitsui Chemicals Co., Ltd.) with respect to 100 parts by mass of resin solids, which is a vehicle-forming component consisting of 25 parts, It added so that solid content might be 20 mass parts, and also the organic solvent was added, and it stirred and mixed, and prepared the coating material of the viscosity in 20 degreeC for 20 second / forward cup # 3. The obtained paint was coated with air atomized electrostatic spray so as to have a cured coating thickness of 20 μm on a base material obtained by solvent degreasing of a steel plate on which an N-6 gray color intermediate coating was previously formed. After leaving it in the laboratory for 5 minutes, the clear paint “Lugabe Kukuriya” (trade name, manufactured by Kansai Paint Co., Ltd., acrylic resin / amino resin type, organic solvent type) is used with a minibell type rotary electrostatic coating machine. The film was coated to a thickness of 30 μm as a cured coating film under the conditions of a boot temperature of 25 ° C. and a humidity of 75%. After coating, it 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 dry and cure the multilayer coating film at the same time, thereby preparing a coated plate for measurement.

The IV value of the obtained coated plate was measured using “Alcoop LMR-200H” manufactured by Kansai Paint Co., Ltd. Specifically, the reflected light from the laser light source irradiated at an incident angle of 45 degrees was used, and the light intensity IV value received by the light receiver at an angle of 10 degrees with respect to the regular reflected light was determined.
Examples 1-8, Comparative Examples 1-3
(Preparation of coating composition)
Resin which is a vehicle forming component comprising 75 parts of the hydroxyl group-containing acrylic resin solution obtained in Production Example 1 as a solid content and 25 parts of Euban 28-60 (trade name, butyl etherified melamine resin, manufactured by Mitsui Chemicals) as a solid content. A scale-like aluminum pigment and a scale-like interference pigment are blended at a ratio shown in Table 1 and mixed with stirring with respect to 100 parts by mass of the solid content, and further diluted by adding an organic solvent to obtain an organic solvent having a solid content of about 25%. A mold paint was prepared, and metallic paint compositions 1 to 9 used in Examples and Comparative Examples were prepared.

(Preparation of color base paint)
Titanium oxide pigment (100 parts of solid component) 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) TIPAQUE CR-95, manufactured by Ishihara Sangyo Co., Ltd.) and carbon black pigment (BLACK PEARLS 1300, manufactured by CABOT CORP., Primary average particle size 13 nm) are mixed at the ratio shown in Table 2 and mixed with stirring to obtain an appropriate viscosity for coating. Dilution was performed to prepare an organic solvent-type paint having a solid content of about 25%, and color base paints 1 to 3 were prepared.

  The lightness L * in the L * a * b * color system of the coating film obtained with the color base paint was measured, and the results are shown in Table 2. Specifically, a color base paint is applied by air spray so as to have a cured coating thickness of 20 μm on a solvent-degreased tin plate, and left in a laboratory at room temperature of about 20 ° C. for 15 minutes, and then used in a hot air circulation drying oven. Then, the coated plate dried by heating at 140 ° C. for 30 minutes was irradiated with light from 45 degrees using MA-68II (trade name, multi-angle spectrophotometer, manufactured by x-rite). Is a numerical value obtained by calculating from the spectral reflectance when the light is received at an angle of 45 degrees from the regular reflection light.

(Creation of test plate)
Preparation of base material 1 Cationic electrodeposition paint “Electron 9400HB” (trade name: manufactured by Kansai Paint Co., Ltd., epoxy resin polyamine-based cation on a steel plate (JISG3141, size 400 × 300 × 0.8 mm) subjected to degreasing and zinc phosphate treatment Electrodeposition of a resin using a block polyisocyanate compound as a curing agent) to a film thickness of 20 μm based on the cured coating film, followed by heating at 170 ° C. for 20 minutes for crosslinking and electrodeposition A coating film 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 applied 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 the substrate 1. The lightness L * in the L * a * b * color system of the substrate 1 was measured in the same manner as the color base coating film, and the numerical values are shown in Table 3.
(2) Preparation of base materials 2 to 4 In the same manner as the base material 1, an intermediate coating film is prepared. On the obtained intermediate coating film, the color base paints 1 to 3 are air-sprayed based on a cured coating film. The film was then coated to a film thickness of 20 μm, heated at 140 ° C. for 30 minutes to be crosslinked and cured, and substrates 2 to 4 were obtained.
(3) Application of metallic paint compositions 1-9 and clear paint The above-mentioned base material is coated with metallic paint compositions 1-9 using air spray so that the cured coating film has a thickness of 20 μm. Allow to stand in a laboratory at 20 ° C for about 15 minutes, and then apply a clear paint "Lugabe Kukuriya" (trade name: manufactured by Kansai Paint, acrylic resin / amino resin type, organic solvent type) to a mini-bell type rotary static Using an electric coating machine, the coating film was applied to a thickness of 30 μm as a cured coating film under the conditions of a boot temperature of 25 ° C. and a humidity of 75%. 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)
The design properties of the test plate were evaluated in the following manner, and the results are shown in Table 3.

(1) Evaluation by visual observation The prepared coated plate is illuminated with an artificial sun lamp (manufactured by Celic, color temperature 6500K), observed at different angles to the illumination of the test plate, and shade whiteness and interference color in highlights The expression of was visually evaluated. The evaluation was conducted by a total of 5 designers and 3 engineers engaged in color development for 3 years or more, and the average score was adopted.
Shade whiteness 4: The whiteness of the shade can be strongly perceived.
3: The shade whiteness can be perceived.
2: The shade white is perceptible weakly.
1: The whiteness of the shade cannot be perceived.
Expression of interference color in highlight When the coated plate is observed with highlight (near specular reflection light) and the relationship between the coated plate and the observer's line of sight is changed slightly,
4: Expression of interference color is remarkable.
3: Interference color is strong.
2: The expression of interference colors is weak.
1: There is no expression of interference color.
(2) Evaluation by colorimetry The spectral reflectance at a plurality of observation angles of the prepared coated plate was measured using MA-68II (trade name) manufactured by X-Rite, and the shade was whitened from the measured spectral reflectance. As a numerical value representing the lightness L * at a light receiving angle of 75 degrees with respect to specular reflection light, and as a numerical value representing the appearance of interference colors in highlights, the saturation C * 15 at a light receiving angle of 15 degrees and a light receiving angle of 45 degrees The ratio (C * 15 / C * 45) with saturation C * 45 was calculated.

The metallic paint composition and the coating film forming method of the present invention can be applied to various industrial products, particularly automobile outer plates.

Claims (6)

A metallic paint composition comprising a scaly aluminum pigment and a scaly interference pigment, wherein the scaly aluminum pigment has an IV value of 100 or more and 250 or less when a coating film is formed. The metallic paint composition according to claim 1, wherein the scaly interference pigment is a translucent scaly substrate coated with titanium oxide, and the scaly substrate is artificial mica or silica flakes. The content of the scaly aluminum pigment is within a range of 0.1 to 25 parts by mass as a solid content with respect to 100 parts by mass of a resin solid content which is a vehicle forming component in the coating composition. Metallic paint composition as described in 2. The metallic paint composition according to any one of claims 1 to 3, wherein the mass ratio of the scaly aluminum pigment and the scaly interference pigment is in the range of 1/1 to 1/6 in the former / latter ratio. The coating-film formation method which applies the metallic coating composition as described in any one of Claims 1-4 to a base material, and also applies a clear coating. The method for forming a coating film according to claim 5, wherein the lightness L * in the L * a * b * color system of the substrate is in the range of 40 to 90.