JP4824958B2 - METALLIC COATING COMPOSITION, COATING FORMATION METHOD, COATING STRUCTURE AND COATED ARTICLE - Google Patents

Description

The present invention relates to a metallic coating composition, a coating film structure, a coating film forming method, and a coated article, which have a large change in brightness from highlight to face and are excellent in depth and density.

In recent years, industrial products such as automobile bodies have been required to have high product power, and one of them is high design. There is a metallic paint color as a paint color with high designability. Usually, the metallic paint color is applied in a so-called 2C1B process in which a clear paint is applied onto a coating film obtained by applying a base paint containing a scale-like metal pigment or the like. Among metallic paint colors, in order to obtain a paint color with a high flip-flop property with a large brightness difference between highlight and shade in a dark gray metallic paint color of low brightness, scaly metal pigments such as aluminum flake pigments and the like It has been common to design a base paint in which a bright pigment such as a mica pigment coated with a metal oxide on a scaly substrate and a black pigment are combined. However, with the conventional methods, a flip-flop feeling can be obtained, but there is a problem that the brightness change from highlight to face is gradual and the brightness is lowered in the entire area.

  In Patent Document 1, as a method for forming a multi-layer coating film having high flip-flop properties by adjusting the brightness while maintaining the color depth without causing white blurring of the shade, reduced titanium oxide coated mica is used as a coloring component. A method of forming a clear coating film on a base coating film containing a pigment and a colored aluminum pigment is disclosed. The coating film obtained by this method does not cause the white blur of the shade, but the brightness change from highlight to face is gradual, the saturation is high in the shade, and it can be applied to dark gray metallic paint color. It was difficult.

JP 2001-314811 A

Therefore, an object of the present invention is a dark gray metallic coating color with low brightness, and a change in brightness from highlight to face is large, and a coating film having a coating color excellent in flip-flop feeling, depth feeling and denseness can be formed. It is to provide a metallic coating composition, a coating film forming method, a coating film structure, and a coated article.

The present invention
1. A metallic paint composition comprising a resin component and a coloring component, wherein a low-brightness luster pigment in which a transparent scaly substrate is coated with low-order titanium oxide obtained by reducing titanium oxide and / or titanium oxide as a coloring component A metallic paint composition comprising two types, wherein one of the low brightness glitter pigments exhibits blue and the other exhibits black, the low brightness glitter pigment exhibiting blue and the low brightness exhibiting black The ratio of the glitter pigment is in the range of 1 / 0.3 to 1 / 1.2 as the solid mass ratio, and the total amount of the low brightness glitter pigment is 1 to 30 masses per 100 mass parts of the resin component. Metallic paint composition characterized by being in the range of parts ,
2. The metallic paint according to claim 1, further comprising a carbon black pigment as a coloring component, the content of which is in the range of 3 to 20 parts by mass with respect to 100 parts by mass of the total amount of the low brightness glitter pigment. Composition,
3. A method of forming a coating film, wherein a top clear coating material is further applied on the coating film obtained by applying the metallic coating composition according to any one of items 1 or 2 to an object to be coated;
4). The coating film structure obtained by the coating film forming method according to Item 3 ,
5). The present invention relates to a coated article obtained by the coating film forming method described in Item 3 .

ADVANTAGE OF THE INVENTION According to this invention, the metallic paint composition and coating-film formation method which can form the coating film of the coating color which is the dark gray metallic coating color of low brightness and low saturation, and was excellent in the flip-flop feeling, the deep feeling, and the dense feeling A coating film structure and a coated article can be obtained.

First, the coating composition of the present invention will be described.

  The coating composition of the present invention contains two kinds of low brightness glitter pigments for adjusting the brightness from highlight to face. Specifically, the transparent scaly substrate contains a low brightness glitter pigment coated with titanium oxide and / or low-order titanium oxide obtained by reducing titanium oxide. Here, the observation angle of the coating film will be described. Highlight means observing the coating film in the vicinity of specular reflection light, and shade means observation at an angle not affected by specular reflection light. “Face” means observation from an angle between the two (watermark direction).

  As the two kinds of low-brightness bright pigments to be blended in the coating composition of the present invention, the above-mentioned transparent scaly base materials are each coated with low-order titanium oxide obtained by reducing titanium oxide and / or titanium oxide. Among the light brightness pigments, those exhibiting a blue color and those exhibiting a black color are preferable. The expression of blue and black here means a coating obtained by measuring a coating film obtained by coating a coating composition containing only one kind of low brightness glitter pigment as a coloring material. It means that the color of the film is blue and black, respectively.

  In the present invention, specifically, 15 parts by mass of each low brightness glitter pigment is blended per 100 parts by mass of a resin component composed of a hydroxyl group-containing acrylic resin (hydroxyl value 100, number average molecular weight 20000) and melamine resin. The paint obtained by mixing with stirring and diluting to an appropriate viscosity for painting and preparing an organic solvent-type paint having a solid content of about 25% is applied onto a coating plate on which a black (N-2) paint film has been formed in advance. As a cured coating film, air spray coating was applied to a film thickness of 18 μm, and allowed to stand at room temperature for 15 minutes, and then a clear coating (Lugabe Kukuriya, Kansai Paint, trade name, acrylic on the uncured coating surface. MA-68II (trade name) manufactured by X-Rite Co., Ltd. (resin / amino resin system, organic solvent type) is used as a cured coating film, and the coating film obtained by air spray coating to 35 μm and further cured and dried. It shall be defined by colorimetric values measured using.

  As the low brightness glitter pigment exhibiting a blue color to be blended in the coating composition of the present invention, the colorimetric value of the test piece prepared by the above procedure is L * 50 or higher, preferably 70 or higher, of highlight (15 °). The hue angle h is preferably in the range of 220 ° to 270 °, preferably in the range of 240 ° to 260 °, and more preferably in the range of 245 ° to 255 °.

  Moreover, as a low brightness glitter pigment which exhibits black, that whose L * of a shade (75 degrees) is 10 or less is preferable, More preferably, it is 5 or less. The L * C * h color system here is a table devised based on the L * a * b * color system defined by the International Commission on Illumination in 1976 and adopted in JIS Z 8729. In the color system, h represents a hue angle, and is an angle moved counterclockwise with the red axis as 0 ° in the chromaticity diagram.

  The low brightness glitter pigment is obtained by reducing a so-called scaly glitter pigment in which a transparent scaly substrate is coated with titanium oxide. Specific examples of the transparent scaly substrate include small pieces such as mica, artificial mica, glass flakes, alumina flakes, and silica flakes.

  By coating the surface of the scaly substrate as described above with titanium dioxide and further reducing a part of the coated titanium dioxide in a low oxygen atmosphere, the transparent scaly substrate is oxidized with titanium oxide and / or oxidized. A low brightness glitter pigment coated with low-order titanium oxide obtained by reducing titanium can be obtained. In the reduction step, by varying the kind of reducing agent, the firing temperature, and the like, a low brightness glitter pigment having a color range from brown to black and blue can be obtained.

  In the coating composition of the present invention, the ratio of the low brightness glitter pigment exhibiting blue and the low brightness glitter pigment exhibiting black is within a range of 1 / 0.3 to 1 / 1.2 as a solid content mass ratio. It is preferable from the point of maximizing the lightness difference from the highlight of the coating color obtained by applying the coating composition to the face, more preferably 1 / 0.5 to 1 / 1.0, particularly preferably It is in the range of 1 / 0.6 to 1 / 0.8.

  The content of these low brightness glitter pigments in the coating composition is in the range of 1 to 30 parts by mass in total 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. The inside is preferable, more preferably in the range of 2 to 18 parts by mass, and particularly preferably in the range of 3 to 15 parts by mass.

  The coating composition of the present invention can further contain a carbon black pigment that controls the shade of the shade as a coloring component. The carbon black pigment may contain one or a combination of two or more conventionally known pigments for inks, paints, and plastics. From the viewpoint of coating depth and color tone, The particle diameter is particularly preferably 3 to 20 nm, more preferably 5 to 15 nm. Specific examples include Monarch 1300 (trade name, manufactured by CABOT, primary particle size: 13 nm), Raven 5000 (trade name, manufactured by Columbia, primary particle size: 11 nm), and the like. One or a combination of two or more can be used depending on the desired color tone.

  The blending amount of the carbon black pigment is preferably in the range of 3 to 20 parts by mass with respect to 100 parts by mass of the solid content of the low brightness glitter pigment in terms of the color tone of the resulting coating film, More preferably, it exists in the range of 5-12 mass parts, Most preferably, it exists in the range of 6-9 mass parts.

  Furthermore, the blending amount of the carbon black pigment is preferably in the range of 0.01 to 3 parts by mass with respect to 100 parts by mass of the resin solid content in the coating composition from the viewpoint of the finished appearance of the resulting coating film. More preferably, it is in the range of 0.1 to 2 parts by mass, particularly preferably in the range of 0.3 to 1.5 parts by mass. The coating composition of the present invention further comprises a titanium dioxide on the surface of a scaly substrate selected from mica, artificial mica, glass flakes, alumina flakes and silica flakes that cause interference colors in the highlight portion as necessary. Coated interference pearl pigments can be included. These contents are preferably 15 parts by mass or less, more preferably in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the resin solid content in the coating composition from the viewpoint of the color tone and finish of the coating film. .

  The coating composition of the present invention may further contain a transparent coloring pigment that controls the color tone of highlights as a coloring component. The transparent colored pigment is formulated into a paint with a pigment amount of 20 parts by mass based on 100 parts by mass of the resin solid content in the paint, and a smooth PTFE plate having a cured coating thickness of 30 μm. A pigment having a light transmittance of 90% or more in the visible light region (wavelength 400 nm to 700 nm) measured with a spectrophotometer MPS-2450 (trade name, manufactured by Shimadzu Corporation) on the coated, cured, and peeled coating film Meaning an average primary particle diameter of 100 nm or less. Specifically, transparent iron oxide pigments, composite metal oxide pigments such as titanium yellow, azo pigments, quinacridone pigments, diketopyrrolopyrrole pigments, perylene pigments, perinone pigments, benzimidazolone pigments, Use any one of indoline pigments, isoindolinone pigments, metal chelate azo pigments, phthalocyanine pigments, indanthrone pigments, dioxane pigments, indigo pigments in combination of one or more. be able to. The content of the transparent pigment is preferably 5 parts by mass or less, more preferably in the range of 0.1 to 3 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. Is within.

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

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

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

  In the coating film forming method of the present invention, the top clear coating film is further applied by coating one or more top clear coatings on the coating film obtained by coating the coating composition as described above on the substrate. To form. Examples of the base material include metals such as iron, zinc, and aluminum, alloys containing these, molded products plated or vapor-deposited with these metals, molded products made of glass, plastic, foam, and the like. be able to. Depending on these materials, it can be appropriately degreased or surface treated to form a substrate. Furthermore, an undercoat film or an intermediate coat film can be formed on the substrate to form a substrate, and these are particularly preferable.

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

  The intermediate coating film is formed to conceal the 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 the case of forming an undercoating film or an intermediate coating film as a substrate, the undercoating film or the intermediate coating film can be heated and coated with the coating composition of the present invention described later after crosslinking and curing. . Alternatively, the undercoating film and / or the intermediate coating film can be applied in an uncured state.

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

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

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

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

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

  The coated article of the present invention is obtained by coating the above-mentioned substrate with the above-described coating film forming method.

Next, an Example is given and this invention is demonstrated more concretely.
Examples and Comparative Examples Substrate adjustment degreasing and zinc phosphate-treated steel plate (JISG3141, size 400 × 300 × 0.8 mm), cationic electrodeposition paint “Electron 9400HB” (trade name: manufactured by Kansai Paint Co., Ltd., epoxy) A resin polyamine-based cationic resin using a block polyisocyanate compound as a curing agent) is electrodeposited to a film thickness of 20 μm based on the cured coating film, and heated at 170 ° C. for 20 minutes to crosslink and cure. To obtain an electrodeposition coating film.

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.
Preparation of paint Stir the pigments and coloring pigments in the ratios shown in Table 1 per 100 parts by mass (solid content) of a resin component comprising a hydroxyl group-containing acrylic resin (hydroxyl value 100, number average molecular weight 20000) and melamine resin. The mixture was mixed and diluted to a viscosity suitable for coating to prepare an organic solvent-type paint having a solid content of about 25%.

Low Brightness Brightness Pigment Colorimetry Table 1 Low light brightness pigment A and low brightness brightness pigment B shown in the column are resin components comprising a hydroxyl group-containing acrylic resin (hydroxyl value 100, number average molecular weight 20000) and melamine resin, respectively. 10 parts by mass per 100 parts by mass (solid content) were mixed with stirring and diluted to an appropriate viscosity for coating to prepare an organic solvent-type paint having a solid content of about 25%.

  The obtained paint was air-sprayed on a coated plate on which a black (N-2) paint film had been formed in advance so as to obtain a film thickness of 18 μm as a cured paint film, left at room temperature for 15 minutes, and then uncured. Clear paint (Lugabe Kukuriya, manufactured by Kansai Paint Co., Ltd., trade name, acrylic resin / amino resin type, organic solvent type) is applied to the coated surface by air spraying to a thickness of 35μm, followed by curing and drying. The obtained coating film was measured using a multi-angle spectrophotometer (MA-68II, trade name, manufactured by X-Rite), and the colorimetric values are shown in Table 2.

Preparation of test plate The coating composition prepared in (2) was applied to the base material prepared in (1), using a REA gun, respectively, at 25 ° C. and 75% humidity as a cured coating film. Then, leave it at room temperature for 15 minutes, and then apply a clear paint (Lugabe Clear, manufactured by Kansai Paint, trade name, acrylic resin / amino resin, organic solvent) to these uncured surfaces. The mold was coated as a cured coating film using a mini-bell rotary electrostatic coating machine under conditions of a boot temperature of 25 ° C. and a humidity of 75% so as to be 25 to 35 μm. After coating, the sample was allowed to stand at room temperature for 15 minutes, and then heated in a hot-air circulating drying furnace at 140 ° C. for 30 minutes to dry and cure the multilayer coating film at the same time for use as an evaluation test. .
Evaluation test The brightness change and the denseness of the test plate prepared in (4) were evaluated, and the results are shown in Table 3.

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 (5)

A metallic paint composition comprising a resin component and a coloring component, wherein a low-brightness luster pigment in which a transparent scaly substrate is coated with low-order titanium oxide obtained by reducing titanium oxide and / or titanium oxide as a coloring component A metallic paint composition comprising two types, wherein one of the low brightness glitter pigments exhibits blue and the other exhibits black, the low brightness glitter pigment exhibiting blue and the low brightness exhibiting black The ratio of the glitter pigment is in the range of 1 / 0.3 to 1 / 1.2 as the solid mass ratio, and the total amount of the low brightness glitter pigment is 1 to 30 masses per 100 mass parts of the resin component. A metallic paint composition characterized by being in the range of parts . Further comprising a carbon black pigment as a coloring component, according to claim 1 the content thereof, characterized in that it is in the range of 3 to 20 parts by mass relative to the total 100 parts by weight of the low brightness bright pigment
The metallic paint composition as described. A method for forming a coating, wherein a top clear coating is further applied onto a coating obtained by applying the metallic coating composition according to any one of claims 1 and 2 to an object to be coated. A coating film structure obtained by the coating film forming method according to claim 3 . The coated article obtained by the coating-film formation method of Claim 3 .