JP2012036330A - Coating composition and method for forming coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating composition capable of forming a coating film which is applicable to various industrial products, especially outer panels of automobiles and of which glossiness is controlled and particle feeling is strong as a whole and hue changes from a highlight (near specularly reflected light) to a shade (in the oblique direction), and a method for forming a coating film.SOLUTION: The coating composition includes a scale-like brilliant pigment and a gloss-adjusting material. In the method for forming a coating film, the coating composition is coated on a substrate. The scale-like brilliant pigment is at least one selected from a glass flake pigment coated with a metal oxide and an alumina flake pigment coated with a metal oxide.

Description

The present invention relates to a coating composition and a method for forming a coating film that can form a coating film that has a suppressed gloss overall, has a strong particle feeling, and exhibits an interference color in highlights (near regular reflection light).

In exterior colors of industrial products such as automobiles, metallic colors whose color appearance changes depending on the viewing angle dominate. So far, in the metallic color, a large color change from a highlight (near regular reflection light) to a shade (oblique direction) and whiteness (high brightness) of the highlight have been pursued. On the other hand, there is a strong demand for a soft texture with suppressed gloss.

  Until now, in order to suppress the gloss of the exterior color, a method for controlling the 20-degree specular gloss value (high gloss area) and the 60-degree specular gloss value (medium gloss area) has been pursued. Furthermore, when pursuing a high design, it is necessary to control the 85-degree specular gloss value (glossiness seen from an oblique direction).

  Patent Document 1 relates to a coating composition capable of obtaining a coating film in which the amount of reflected light and the hue change depending on the viewing angle, and 60 degrees of the coating film obtained by applying a light interference pigment and a matting agent. A coating composition containing a specular gloss value of 30 or less is disclosed. Although the coating film obtained by applying the coating composition disclosed in Patent Document 1 has a flip-flop feeling and a coating film with low gloss, a coating film having a strong particle feeling cannot be obtained. There was a problem.

JP 2002-327150 A

SUMMARY OF THE INVENTION An object of the present invention is to provide a coating composition and a coating film forming method capable of forming a coating film in which gloss is suppressed as a whole, a particle feeling is strong, and an interference color is expressed in highlight (near regular reflection light). It is.

The present invention
1. A coating composition comprising a scaly interference pigment and a gloss adjusting material,
2. The coating composition according to 1, wherein the scaly interference pigment is at least one selected from a glass flake pigment coated with a metal oxide or an alumina flake pigment coated with a metal oxide,
3. Item 3. The coating composition according to Item 1 or 2, wherein the gloss adjusting material is finely divided silica.
4). The coating composition according to any one of items 1 to 3, wherein the coating film obtained by coating has a 60 ° specular gloss of 30 or less and an 85 ° specular gloss of 30 or less,
5. It is related with the coating-film formation method which coats the base material with the coating composition described in any one of Claims 1-4.

  According to the present invention, it is possible to obtain a coating composition and a coating film forming method capable of forming a coating film that suppresses gloss, has a strong particle feeling, and exhibits an interference color in highlights (near regular reflection light).

  The coating composition of the present invention contains a scaly interference pigment for the purpose of expressing an interference color with the highlight of a coating film obtained by coating.

  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 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 from the viewpoint of particle feeling in the multilayer coating film, the glass flake pigment or metal oxide coated with a metal oxide It is preferred to use one or more selected from alumina flake pigments coated with.

  The metal oxide-coated glass flake pigment is obtained by coating a scale-like glass substrate with a metal oxide, and since the substrate surface is smooth, strong light reflection occurs and expresses a particle feeling. Although it does not restrict | limit especially as a metal oxide to coat | cover, Titanium oxide and iron oxide are known.

  An alumina flake pigment coated with a metal oxide is a glitter pigment in which an alumina flake base material is coated with a metal oxide. The alumina flake base material means scaly (flaky) aluminum oxide and is colorless and transparent. It does not need to be a single component of aluminum oxide, and may contain an oxide of another metal (for example, titanium oxide).

  The glitter pigment in which the metal oxide is coated on the alumina flake base material is subjected to a surface treatment for further improving dispersibility, water resistance, chemical resistance, weather resistance and the like after the metal oxide is coated. It may be a thing. Although it does not restrict | limit especially as a metal oxide to coat | cover, Titanium oxide and iron oxide are known.

  As for the size of the scaly interference pigment, it is preferable to use a pigment having an average particle diameter 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 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 referred to here are values obtained by observing the scaly interference pigment with an optical microscope or an electron microscope, or values measured with a particle size distribution measuring apparatus using a laser such as a laser diffraction method. means.

  Further, the content of the scaly interference pigment is in the range of 0.01 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. The inside is preferable, more preferably within the range of 0.03 to 23 parts by mass, and particularly preferably within the range of 0.05 to 20 parts by mass.

  The coating composition of the present invention contains a gloss adjusting material for the purpose of suppressing the gloss of the coating film obtained by coating. The gloss adjusting material has the effect of adjusting the gloss of the coating film by appropriately scattering incident light by being present in the coating film as a particle component having a refractive index different from that of the vehicle component of the coating film. . In general, finely divided silica (hydrous silicon dioxide), polyethylene powder, resin beads, ceramic beads, or a dispersion obtained by pre-dispersing them is used. Of these, finely divided silica, a dispersion obtained by predispersing finely divided silica, and resin beads are preferable, and particularly preferable is finely divided silica. However, the present invention is not limited, and one type of gloss adjusting material is used depending on the desired texture. Or 2 or more types can be selected and used. Also. As the gloss adjusting material, those having an average particle diameter of 0.01 to 50 μm are preferable from the viewpoint of the effect of suppressing the gloss of the coating film obtained by coating, and more preferably 0.05 to 40 μm. is there. The particle diameter here means a numerical value obtained by observing the gloss adjusting material 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.

  A preferable blending amount of the gloss adjusting material in the coating composition of the present invention is 1 to 50 parts by mass with respect to 100 parts by mass of the vehicle solid content in the coating composition. If it is less than 1 part by mass, the effect of suppressing the gloss of the coating film is insufficient, and if it exceeds 50 parts by mass, the finished appearance of the coating film may be deteriorated. More preferably, it is 5-30 mass parts.

  The coating composition of the present invention can also contain a color pigment. The coloring pigment is not particularly limited, but specifically, inorganic pigments such as carbon black, titanium dioxide, transparent iron oxide pigments, complex yellow pigments such as titanium yellow, azo pigments, quinacridone Pigment, diketopyrrolopyrrole pigment, perylene pigment, perinone pigment, benzimidazolone pigment, isoindoline pigment, isoindolinone pigment, metal chelate azo pigment, phthalocyanine pigment, anthraquinone pigment, dioxazine Any one or more of organic pigments such as pigments, selenium pigments, indigo pigments and the like can be used in combination.

  When the color pigment is blended in the coating composition of the present invention, the content thereof is based on 100 parts by mass of the resin solid content in the coating from the viewpoint of the saturation in the highlight of the coating film obtained by coating and the brightness of the shade. It is preferably in the range of 0.01 to 30 parts by mass, more preferably 0.03 to 25 parts by mass, and particularly preferably 0.05 to 20 parts by mass.

The coating composition of the present invention can usually contain a resin component as a vehicle.
Specifically, as the resin component, 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, a melamine resin, a urea resin, a polyisocyanate compound (block body). Are used in combination with a crosslinking agent such as an organic solvent and / or a solvent such as water.

Furthermore, in the 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 rheology control agents, extender pigments and the like 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 coating is 12 to 60% by mass, preferably 15 to 50%, based on the coating composition.
It is preferable to adjust to mass%.

  In the coating film forming method of the present invention, the coating composition as described above is applied to a substrate.

  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. Depending on these materials, it can be appropriately degreased or surface treated to form a substrate. Furthermore, an undercoating film or an intermediate coating film can be formed on the substrate to form a substrate, and these coated substrates 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 undercoating film, or to impart adhesion or chipping resistance. It can be obtained by applying a paint and 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 forming an undercoat film or an intermediate coat film as a base material, the undercoat film or the intermediate coat film is heated or irradiated with an electron beam to apply a coating for the next step described later after crosslinking and curing. Can do. Alternatively, the coating composition of the present invention can be applied in a state where the undercoat film and / or the intermediate coat film is uncured.

  In the method for forming a coating film of the present invention, a base coat film having a spectral reflectance of 80% or more in the range of 80% or more can be used as a base material from the viewpoint of emphasizing an interference color in a particle feeling or highlight. . In the present specification, the spectral reflectance of the visible light portion of the base coat film is determined by applying 45 to the paint film using MA-68II (trade name) manufactured by X-Rite Co., Ltd. It is defined as a numerical value obtained by measuring the spectral reflectance within a wavelength range of 400 to 700 nm when light irradiated from an angle of degrees is received at an angle of 25 degrees with respect to specularly reflected light.

  The base coat film can be formed by applying a base coat paint. As the base coat paint, scaly glittering pigments and / or colored pigments and organic solvent-based or water-based paints containing a vehicle-forming component can be used.

  As the scaly glitter pigment in the base coat paint, for example, when it is desired to obtain a coating film whose brightness changes greatly between highlight and shade, the above scaly aluminum pigment can be used. The content is preferably in the range of 0.01 to 25 parts by mass, more preferably 0, based on 100 parts by mass of the resin solid content in the paint from the viewpoint of the finish of the coating film obtained by coating. It is in the range of 0.03 to 23 parts by mass, particularly preferably in the range of 0.05 to 20 parts by mass.

  Or, if you want to obtain a solid color coating with high saturation (color does not change depending on the viewing angle) as the base coat film, use transparent iron oxide pigments, complex yellow metal oxide pigments such as titanium yellow, and azo pigments. , Quinacridone pigments, diketopyrrolopyrrole pigments, perylene pigments, perinone pigments, benzimidazolone pigments, isoindoline pigments, isoindolinone pigments, metal chelate azo pigments, phthalocyanine pigments, indanthrone pigments Any one of pigments, dioxane pigments, selenium pigments, indigo pigments and the like can be used in combination of one or more. The content is preferably in the range of 0.01 to 30 parts by mass, more preferably 100 parts by mass with respect to 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. It is in the range of 0.1 to 25 parts by mass, particularly preferably in the range of 0.5 to 20 parts by mass.

  The base coat paint 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, for base coat paints, as necessary, various additives such as solvents such as water or organic solvents, pigment dispersants, anti-settling agents, curing catalysts, antifoaming agents, antioxidants, UV absorbers, extender pigments. Etc. can be appropriately blended.

  The base coat paint is prepared by mixing and dispersing the aforementioned components. The solid content during coating is preferably adjusted to 12 to 50% by mass, preferably 15 to 30% by mass, based on the coating composition.

  In the coating film forming method of the present invention, when the base coat coating film is used as the base material, the coating film by the base coating paint may be dried and cured, or may be uncured. In that case, after the coating composition is applied to an uncured base coat coating, it can be heated to cure the two coating layers simultaneously.

  The coating composition of the present invention can be applied by a method such as electrostatic coating, air spraying, airless spraying, and the film thickness is within the range of 5 to 30 μm based on the cured coating film. From the viewpoint of smoothness. 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 coating composition of the present invention can be crosslinked and cured usually at a temperature of about 50 to about 150 ° C. in the case of a baking dry type, and in the case of a normal temperature drying type or a forced drying type, It can be cross-linked and cured at a temperature from dry to about 80 ° C.

  In the coating film forming method of the present invention, a clear paint containing the above-described gloss adjusting material is further applied to one or more layers on the coating film obtained by applying the coating composition on a substrate, A clear coating film can be formed.

  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-described coating composition. The clear coating is mainly composed of a resin component and a solvent, and, if necessary, other coating additives. Is a liquid paint that forms a colorless or colored transparent coating film. As the gloss adjusting material in the clear paint, the above-mentioned gloss adjusting material can be used. The content is 1 to 50 parts by mass with respect to 100 parts by mass of the vehicle solid content. If it is less than 1 part by mass, the gloss of the coating film becomes high, and if it exceeds 50 parts by mass, the finished appearance of the coating film may be deteriorated. More preferably, it is 5-30 mass parts.

  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. As a crosslinking agent, melamine resin, urea resin, polyisocyanate compound, block polyisocyanate compound, epoxy compound or resin, carboxyl group-containing compound or resin, acid anhydride, alkoxysilane group-containing, which can react with the functional group of the base resin Examples thereof include 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 0.01 to 10 mass parts.

  The clear coating in the present invention can be applied by a method such as electrostatic coating, air spraying, airless spraying, 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 150 ° C. in the case of a baking drying type, and in the case of a room temperature drying type or a forced drying type, it is room temperature drying to about 80. Crosslinking and curing can be performed at a temperature of ° C.

In the coating film forming method of the present invention, after coating the coating composition of the present invention as described above, heating,
After drying and curing, the above clear coating may be applied to the coating film, heated, and dried and cured. However, after the coating composition is applied, the top clear coating is applied in an uncured state. Then, a multilayer coating film can also be obtained in the step of heating and drying and curing these simultaneously.

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.
Examples 1-6, Comparative Examples 1-3
(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%. 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 (2-methylpropionitrile) A mixture of 2 parts.

(Preparation of base coat)
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, Inc.) Gloss adjusting materials and color pigments are blended in the ratios shown in Table 1, mixed with stirring, diluted to an appropriate viscosity for coating, and an organic solvent-type paint having a solid content of about 25% is prepared. Base coats 1 to 5 to be used were prepared. Base coat paint 3 was applied to a smooth tin plate previously degreased so as to have a film thickness of 20 μm as a cured coating film, left in a laboratory at room temperature of about 20 ° C. for 15 minutes, and then heated at 140 ° C. for 30 minutes for crosslinking. The spectral reflectance of the visible light part of the coating film obtained by curing was 130% (trade name: MA-68II manufactured by X-Rite was used to irradiate the coating film from an angle of 45 degrees. Spectral reflectance within a wavelength range of 400 to 700 nm when light is received at an angle of 25 degrees with respect to specularly reflected light).

(Preparation of clear coat)
Clear paint (Lugabe Kukuriya, manufactured by Kansai Paint Co., Ltd., trade name, acrylic resin / amino resin type, organic solvent type) per 100 parts (solid content) of resin component, gloss pigment, gloss adjusting material, coloring pigment 1 is blended at a ratio shown in FIG. 1, stirred and mixed, diluted to an appropriate viscosity for coating, an organic solvent-type paint having a solid content of about 40% is prepared, and clear coats 1 to 5 used in Examples and Comparative Examples are prepared. Prepared.

(Creation of test plate)
Plate with intermediate coating film Degreased and zinc phosphate-treated steel plate (JISG3141, size 400 x 300 x 0.8 mm), cationic electrodeposition paint "Electron 9400HB" (trade name: Kansai Paint Co., Ltd.) Made of epoxy resin polyamine-based cationic resin using block polyisocyanate compound as curing agent) based on the cured coating film, electrodeposited to a film thickness of 20 μm, and heated at 170 ° C. for 20 minutes for crosslinking and curing To obtain an electrodeposition coating film.

On the surface of the electrodeposited coating, 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 prepared.
Painting <br/> Example 1: The base coat 1 on the substrate using an air spray, was applied to a 20μm as cured coating film, after application, allowed to stand for about 15 minutes to the laboratory at room temperature about 20 ° C. Later, it was used in a hot air circulating drying oven, heated at 140 ° C. for 30 minutes, and dried and cured to obtain a test plate.
Examples 2 and 3: A test plate was obtained in the same manner as in Example 1 so as to have the configuration shown in Table 1.
Example 4: The base coat 3 was applied to the above base material using an air spray so as to have a cured coating thickness of 20 μm. After coating, the base coat 3 was allowed to stand in a laboratory at a room temperature of about 20 ° C. for about 15 minutes, and then cleared. Coat 1 was applied as a cured coating film to a thickness of 30 μm. After coating, the sample was allowed to stand at room temperature for 15 minutes, and then heated at 140 ° C. for 30 minutes using a hot air circulating drying oven to simultaneously dry and cure the multilayer coating film to obtain a test plate.
Examples 5 and 6 and Comparative Examples 1-3: Test plates were obtained in the same manner as in Example 4 so as to have the constitution shown in Table 1.
(Evaluation)
The design properties of the test plate were evaluated in the following manner, and the results are shown in Table 1.
The prepared coated plate is illuminated with an artificial sunlamp (Ceric, color temperature 6500K), and observed at a different angle with respect to the illumination of the test plate. From the highlight (near the specular reflection light) to the shade (oblique direction) Lightness change and hue change were evaluated visually according to the following criteria. 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.
Particle feeling 4: Particle feeling is strong.
3: There is a feeling of particles.
2: Poor graininess.
1: There is no particle feeling.
Glossiness Regarding glossiness, 60 degree specular glossiness and 85 degree specular glossiness were measured using Micro tri-gloss (trade name, gloss meter, manufactured by BYK Gardner), and the results are shown in Table 1. Indicated.

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

Claims (5)

A coating composition comprising a scaly interference pigment and a gloss adjusting material. The coating composition according to claim 1, wherein the scaly interference pigment is at least one selected from a glass flake pigment coated with a metal oxide or an alumina flake pigment coated with a metal oxide. The coating composition according to claim 1 or 2, wherein the gloss adjusting material is finely divided silica. The coating composition according to any one of claims 1 to 3, wherein the coating film obtained by coating has a 60-degree specular gloss of 30 or less and an 85-degree specular gloss of 30 or less. The coating-film formation method which coats the base material with the coating composition as described in any one of Claims 1-4, and also paints a clear coating material.