JP4971611B2 - Metallic coating composition, multilayer coating film forming method, coating film structure and coated article - Google Patents

Description

The present invention relates to a metallic coating composition having excellent design properties, a multilayer coating film forming method, a coating film structure, and a coated article.

The purpose of applying the paint is to protect the material and impart aesthetics. In recent years, especially in the fields of automobile skins and home appliances, consumer demands for aesthetics have been diversified. In addition to conventional solid paint colors, bright pigments such as aluminum pigments and mica pigments have been used. Metallic paint colors and pearl paint colors have been widely used.

  Among these metallic paint colors and pearl paint colors, so-called white pearl paint colors having high whiteness are particularly popular for luxury cars. The above-mentioned white pearl coating color is usually a multi-layer consisting of a base coating film containing a titanium dioxide pigment, a metallic base coating film containing a glittering pigment obtained by coating a scaly substrate with titanium dioxide, and a top clear coating film. Consists of a coating film.

  Among white pearl paint colors, a bright pigment using alumina flakes as a scaly substrate may be used in order to express a particularly bright highlight. This type of glittering pigment is a highlight and gives a strong glittering feeling, but the glittering pigment used in the top coating has a slightly larger particle size, resulting in a grainy feeling and lack of denseness. There was a case.

  Therefore, a bright pigment having a relatively small particle size has been used for the white pearl coating color which requires a fine feeling. In general, a glitter pigment having a small particle diameter has a problem that the glitter feeling of highlight is weak as compared with the glitter pigment using alumina flake as the scale-like substrate. In addition, a bright pigment that uses natural mica as a general base material as a bright pigment having a small particle size may emit a complementary yellow color of interference color, and has a problem of impairing the high-quality feeling of the coating color. It was.

  In Patent Document 1, a color base coating film, a mica base coating film, and a clear coating film are sequentially formed on a substrate by a wet-on-wet method, in which the mica base coating film contains silica particles, It describes a method for forming a pearl coating film characterized by containing at a pigment concentration (PWC) of 0.01 to 5%. Silica particles are almost uniformly dispersed on the surface of the mica pigment in the mica-based paint film, resulting in irregular reflection of light on the surface of the mica pigment, and light reflection when viewed as a mica-based paint film. A pearl coating that has the effect of irregularly reflecting and changing the angle or light reflection intensity, suppressing white turbidity and colorlessness when viewed from the shade position, and having pearl, glitter, and glitter from any direction. However, it is not possible to obtain a strong glitter feeling in highlights.

JP 2001-170559 A

An object of the present invention is to provide a metallic coating composition, a multilayer coating film forming method, a coating film structure, and a coated article, which can provide a coating film with a high brightness, a bright feeling, an excellent denseness, and a low yellowish appearance. It is to be.

The present invention
1. 0.1 to 50 parts by weight of the glitter pigment (A) having a particle size of 5 to 14 μm, in which the alumina flake base material is coated with titanium oxide with respect to 100 parts by weight of the vehicle-forming resin composition, and the alumina flake base material Blue interference color in which titanium oxide is coated on a bright pigment (B) having a particle diameter of 15 to 25 μm coated with titanium oxide and a scaly substrate selected from natural mica, artificial mica, silica flakes and glass flakes A metallic paint composition comprising an interference pearl pigment (C) that expresses a pigment, wherein the mass ratio of the glitter pigments (A) and (B) is 10/1 to 1/3 object,
2. A method for forming a multi-layer coating film, wherein a top clear coating material is further applied on a coating film obtained by applying the metallic coating composition according to item 1 to an object to be coated ;
3. A method for forming a multi-layer coating film in which a metallic paint composition is applied in a plurality of stages, wherein the total content of the glitter pigment contained in the metallic paint composition to be applied in the first stage is applied in the second stage. 3. The method for forming a multilayer coating film according to 2, wherein the ratio of the glittering pigment contained in the metallic coating composition to the total content is 1 / 1.5-1 to 1/10 as a solid content. ,
4). Coating film structure obtained by the multilayer coating film forming method according to 2 or 3 ;
5. The present invention relates to a coated article obtained by the method for forming a multilayer coating film according to item 2 or 3 .

The metallic paint composition of the present invention comprises two kinds of glitter pigments in which an alumina flake base material is coated with titanium oxide, and has high highlight and glitter, less yellowness and a dense feeling. A coating film having an excellent appearance can be obtained, and is particularly useful in a field where a high-grade appearance is required, such as an automobile outer plate and a home appliance.

The metallic paint composition of the present invention comprises a glitter pigment in which an alumina flake base material is coated with titanium 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 above-mentioned glitter pigment with titanium oxide coated on the alumina flake base material has been subjected to surface treatment to further improve dispersibility, water resistance, chemical resistance, weather resistance, etc. after coating with titanium oxide. There may be.

The metallic paint composition of the present invention comprises two kinds of glitter pigments in which the alumina flake base as described above is coated with titanium oxide. On the other hand, (A) has a particle size of 5 to 14 μm, preferably 7 to 12 μm, particularly preferably 7 to 11 μm. On the other hand, (B) has a particle size of 15 to 22 μm, preferably a particle size of 16 to 21 μm, particularly preferably 17 to 20 μm. Both have a thickness of 0.05 to 0.5 μm. The particle diameter and thickness here mean numerical values obtained by observation with an optical microscope or an electron microscope. Examples of commercially available products include the Xiralic ^TM series (product name, manufactured by Merck & Co., Inc.).

  In the metallic paint composition of the present invention, the content of the two types of glitter pigments (A) and (B) is such that one (A) is a solid content with respect to 100 parts by mass of the vehicle-forming resin composition in the paint composition. It exists in the range of 0.1-50 mass parts, Preferably it exists in the range of 1-30 mass parts, More preferably, it exists in the range of 3-25 mass parts. The mass ratio of the glitter pigments (A) and (B) is in the range of 10/1 to 1/3, preferably in the range of 10 / 1.5 to 10/10, as the solid content. Preferably it exists in the range of 5/1-5/4.

  The metallic paint composition of the present invention may further contain an interference pearl pigment (C) in which a scaly substrate selected from natural mica, artificial mica, glass flakes, and silica flakes is coated with titanium oxide. The interference pearl pigment can control the color of the interference color by the amount of titanium oxide coated on the scale-like substrate, that is, the thickness of the titanium oxide layer formed on the surface of the scale-like substrate. In particular, an interference pearl pigment that expresses a blue interference color is preferably blended.

  Normally, in white pearl paint color, it is said that whiteness is felt more when there is a slight bluishness. For this purpose, it is conceivable to mix a small amount of a color pigment exhibiting a blue color into the metallic base paint or an interference pearl pigment that expresses a blue interference color. The method of blending a small amount of a blue coloring pigment has a problem that the color varies depending on the degree of dispersion of the blue pigment, and the color of the coating color deteriorates due to the color change of the blue pigment. In addition, the method of blending an interference pearl pigment that expresses a blue interference color is particularly a paint color that contains a lot of glitter pigments based on natural mica, and yellow, which is a complementary color of the interference pearl pigment, is slightly different from that of natural mica. There was a defect that it was amplified in yellow and yellowish in shade. Since the coating composition of the present invention uses a bright pigment in which a titanium oxide is coated on an alumina flake base material having no yellow tint, an interference pearl pigment that expresses a blue interference color can be blended.

  The content of the interference pearl pigment expressing the blue interference color in the metallic coating composition of the present invention is 0.05 to 50 parts by mass as a solid content with respect to 100 parts by mass of the vehicle-forming resin composition in the coating composition. And preferably in the range of 0.1 to 30 parts by mass, more preferably in the range of 0.2 to 10 parts by mass.

  The metallic paint composition of the present invention can contain other color pigments in addition to the glitter pigment. As the color pigment, conventionally known pigments for ink and paint can be used alone or in combination of two or more. Specific examples of the color pigment include metal oxide pigments such as titanium oxide and iron oxide, composite metal oxide pigments such as titanium yellow, carbon black, azo pigments, quinacridone pigments, diketopyrrolopyrrole pigments, and perylene pigments. Pigments, perinone pigments, benzimidazolone pigments, isoindoline pigments, isoindolinone pigments, metal chelate azo pigments, phthalocyanine pigments, indanthrone pigments, dioxane pigments, indigo pigments, etc. it can.

  When using the above-mentioned color pigment, the blending amount is 50 parts by mass or less with respect to 100 parts by mass of the vehicle-forming resin composition in the coating composition from the viewpoint of coloring power and finished appearance of the coating film to be obtained. It is preferable that it is 0.1-20 mass parts especially preferably.

  As the vehicle-forming resin composition used in the metallic coating composition of the present invention, a thermosetting resin composition is preferable. Specifically, for example, an acrylic resin or a polyester resin having a crosslinkable functional group such as a hydroxyl group. , Alkyd resins, urethane resins and other base resins, and melamine resins, urea resins, polyisocyanate compounds (including block bodies) and other cross-linking agents may be used in combination, such as organic solvents and / or water. It can be used by dissolving or dispersing in a solvent.

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

  Next, the multilayer coating film forming method of the present invention will be described.

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

  The above-mentioned undercoat film is used to conceal the surface of the material, impart anticorrosion and rustproofness to the material, and further improve the adhesion between the intermediate coat film and topcoat film described later and the material. It is formed and can be obtained by applying and curing an undercoat. The type of the undercoat paint is not particularly limited, and examples thereof include an electrodeposition paint and a solvent-type primer.

  The intermediate coating film is formed to conceal the surface of the material or the undercoating film, or to impart adhesion or chipping resistance. It can be obtained by applying and curing a paint. The type of the intermediate coating is not particularly limited, and known ones can be used. For example, an organic solvent-based or water-based intermediate coating containing a thermosetting resin composition and a color pigment can be preferably used.

  In the method of the present invention, in the case of using a base coat and / or an intermediate coat film formed as a substrate, the base coat film and / or the intermediate coat film is heated, and after the crosslinking and curing, the metallic The coating composition can be applied, but the metallic coating composition can also be applied in a state where the undercoat and / or the intermediate coat is uncured. Include.

  In the method of the present invention, the above-mentioned metallic paint composition can be applied onto the base material as described above. Alternatively, the metallic paint composition may be applied to the cured or uncured coating surface after previously applying a color base coating material that conceals the color of the substrate and determines the color tone of the multilayer coating film.

  The color base paint contains a color pigment and a vehicle-forming resin composition. As the color pigment, conventionally known pigments for ink and paint can be used alone or in combination of two or more. Specific examples of the color pigment include metal oxide pigments such as titanium oxide and iron oxide, composite metal oxide pigments such as titanium yellow, carbon black, azo pigments, quinacridone pigments, diketopyrrolopyrrole pigments, and perylene pigments. Pigments, perinone pigments, benzimidazolone pigments, isoindoline pigments, isoindolinone pigments, metal chelate azo pigments, phthalocyanine pigments, indanthrone pigments, dioxane pigments, indigo pigments, etc. it can.

  The blending amount of the color pigment is preferably 50 parts by mass or less, particularly preferably 1 with respect to 100 parts by mass of the vehicle-forming resin composition of the color base paint from the viewpoint of coloring power and finished appearance of the obtained coating film. -30 mass parts.

  The vehicle-forming resin composition is preferably a thermosetting resin composition. Specifically, for example, a base resin such as an acrylic resin, a polyester resin, an alkyd resin, or a urethane resin having a crosslinkable functional group such as a hydroxyl group. And a combination of a crosslinking agent such as a melamine resin, a urea resin, or a polyisocyanate compound (including a block body), and these should be used by dissolving or dispersing in a solvent such as an organic solvent and / or water. Can do.

  Furthermore, the color base paint may be various solvents such as water or organic solvents, rheology control agents, pigment dispersants, antisettling agents, curing catalysts, antifoaming agents, antioxidants, ultraviolet absorbers, etc. Additives, extender pigments and the like can be appropriately blended.

  In the present invention, the color base paint can be applied by a method such as electrostatic coating, air spray, airless spray, and the film thickness is based on the cured coating film from the viewpoint of the smoothness of the coating film. It is preferable to be in the range of 5 to 40 μm.

  In the method of the present invention, the metallic base coating composition can be applied on the coating film on which the color base coating is applied and cured, but the above-mentioned metallic coating is applied on the uncured coating without heating and curing the color base coating. The coating composition can be applied. The color base paint film itself can be cured and dried at a temperature of about 70 to about 150 ° C.

  In the present invention, it is preferable that the metallic coating composition described above is coated with a plurality of stages to form a coating film, particularly in order to arrange the glitter pigment in parallel with the coating film surface. The method of painting in multiple stages is a method of forming a coating film that is originally formed by a single painting in multiple stages (stages), which takes a setting time between each stage. means. In the case of painting at a plurality of stages, the number of times is not particularly limited, but is preferably twice from the viewpoint of the efficiency of the painting operation and the finish of the coating film to be formed. When painting in two stages, the paint applied in the first stage and the paint applied in the second stage may be the same, but the effect of arranging the glitter pigment parallel to the coating surface The content of the bright pigment contained in the coating composition to be applied in the first stage and the bright pigment contained in the coating composition to be applied in the second stage It is preferable that the ratio to the content of is in the range of 1 / 1.5-1 to 1/10 as solid content, more preferably in the range of 1/2 to 1/6, particularly preferably. Is in the range of 1 / 2.5 to 1/4.

  In the case of coating in two stages, the ratio of the dry film thickness of the coating film obtained by the first stage coating to the dry film thickness obtained by the second stage coating is 10/1 to 1.2 / 1. Preferably, it is formed so as to be within the range of 7/1, more preferably within the range of 7/1 to 1.5 / 1, and particularly preferably within the range of 5/1 to 2/1. Specifically, when the dry film thickness is 15 μm, for example, the dry film thickness of the first stage can be 10 to 12 μm, and the second stage can be coated to be 3 to 5 μm.

  In the case of painting in two stages, it is preferable to adjust the non-volatile content in the range of 15 to 50% by mass, and more preferably in the range of 20 to 40% by mass, for the paint to be applied in the first stage. Of these, particularly preferably in the range of 23 to 35% by mass. The coating material applied in the second stage is preferably adjusted to have a nonvolatile content in the range of 2 to 25% by mass, more preferably in the range of 5 to 20% by mass, and particularly preferably in the range of 7 to 15% by mass. It is. By increasing the non-volatile content of the paint to be applied in the first stage and decreasing the non-volatile content of the paint to be applied in the second stage, the effect of arranging the glitter pigment in parallel with the coating surface can be further enhanced.

  Furthermore, in the case of painting in two stages, it is preferable that the setting time between the second stage painting after the first stage painting is usually within a range of 30 seconds to 5 minutes. Is in the range of 45 seconds to 3 minutes, particularly preferably in the range of 1 minute to 2 minutes.

  In the present invention, the metallic base paint can be applied by a method such as electrostatic coating, air spray, airless spray, etc., and its film thickness is a cured coating from the viewpoint of the smoothness of the coating film and glitter. It is preferable to be in the range of 5 to 40 μm based on the membrane.

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

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

  As the top clear coating material of the present invention, conventionally known ones can be used without limitation. For example, a liquid or powdery coating composition containing a base resin and a crosslinking agent can be applied. Examples of the base resin include acrylic resin, polyester resin, alkyd resin, fluororesin, urethane resin, and silicon-containing resin containing a crosslinkable functional group such as a hydroxyl group, a carboxyl group, a silanol group, and an epoxy group. It is done. As a crosslinking agent, a melamine resin capable of reacting with the functional group of the base resin, urea resin, polyisocyanate compound, block polyisocyanate compound, epoxy compound or resin, carboxyl group-containing compound or resin, acid anhydride, Examples thereof include alkoxysilane group-containing compounds or resins. Moreover, additives, such as solvents, such as water and an organic solvent, a curing catalyst, an antifoamer, and a ultraviolet absorber, can be suitably mix | blended as needed.

  In the top clear paint in the present invention, a color pigment can be appropriately blended 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 addition amount 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 vehicle-forming resin composition in the clear coating composition.

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

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

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.
Examples 1 to 3, Reference Examples 1 to 3, and Comparative Examples 1 to 5
(1) Adjusting degreasing of base material and steel plate treated with zinc phosphate (JISG 3141, size 400 × 300 × 0.8 m
m) Cationic electrodeposition paint “Electron 9400HB” (trade name: manufactured by Kansai Paint Co., Ltd., using an amine-modified epoxy resin cationic resin and a block polyisocyanate compound as a curing agent) based on the cured coating film Electrodeposition coating to a film thickness of 20 μm, and 17
The electrodeposition coating film was obtained by heating at 0 ° C. for 20 minutes for crosslinking and curing.

On the surface of the resulting electrodeposition, an intermediate coating “Lugerbake intermediate coating gray” (trade name: polyester resin / melamine resin organic solvent-based coating manufactured by Kansai Paint Co., Ltd.) 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.
(2) Preparation of paint Table 1 shows a glittering material and, if necessary, a colored pigment as a solid content per 100 parts by mass of a vehicle-forming resin composition comprising a hydroxyl group-containing acrylic resin (hydroxyl value 100, number average molecular weight 20000) and melamine resin The organic solvent-type paint was prepared by mixing at the ratio shown in the above and stirred to prepare a color base paint and a metallic base paint used in each of Examples , Reference Examples and Comparative Examples.

  The top clear paint is diluted to an appropriate viscosity for clear paint (Lugabe Kukuriya, manufactured by Kansai Paint Co., Ltd., trade name, acrylic resin / amino resin type, organic solvent type), and the solid content is about 30% by mass. A clear paint was made.

(3) Preparation of test plate In the following procedure, a color base paint and a metallic base paint were applied, and a top clear paint was applied to obtain a test plate.
(Color base paint application)
To the intermediate coating plate prepared in (1), the color base paint prepared in (2) is diluted with an organic solvent and adjusted to a solid content of 25% by mass. Temperature 20 ° C,
The paint was applied under the condition of 75% humidity. After coating, the mixture 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 obtain a cured coating film having a thickness of 30 μm.
(Painting of metallic base paint)
For Example 1, Reference Example 1 and Comparative Examples 1 and 2, on the color base coating film, the metallic base paint prepared in (2) was diluted with an organic solvent to adjust the solid content to 25% by mass. The coating film was applied to a thickness of 15 μm as a cured coating film under the conditions of a boot temperature of 20 ° C. and a humidity of 75%.

For Examples 2 and 3, Reference Examples 2 and 3, and Comparative Examples 3 to 5, the metallic base paint prepared in (2) was applied to the color base coating film using a REA gun, a boot temperature of 20 ° C., and humidity. Under the condition of 75%, the cured coating film was applied in two stages so as to be 15 μm. In the first stage, the metallic base paint prepared in (2) is diluted with an organic solvent to adjust the solid content to 30% by mass, and using a REA gun, under conditions of a boot temperature of 20 ° C. and a humidity of 75%, The cured coating film was applied so as to have a thickness of 10 μm. After painting, it was allowed to stand at room temperature for 60 seconds (setting), and the second stage was painted. In the second stage, the metallic base paint prepared in (2) is diluted with an organic solvent to adjust the solid content to 10% by mass, and using a REA gun, under conditions of a boot temperature of 20 ° C. and a humidity of 75%, The cured coating film was applied so as to have a thickness of 10 μm.
(Coating of top clear paint)
After painting the metallic base paint, it is allowed to stand at room temperature for 15 minutes, and then the top clear paint prepared in (2) is applied to these uncured paint surfaces using a minibell rotary electrostatic coater. The cured coating film was coated to a thickness of 25 to 35 μm under the conditions of a temperature of 20 ° C. and a humidity of 75%. After painting, let stand at room temperature for 15 minutes, then use a hot air circulation drying oven, 140
It was heated at 0 ° C. for 30 minutes, and the multilayer coating film was simultaneously dried and cured to obtain a test plate.
(4) About the test plate obtained in the evaluation test (3), the glitter feeling was evaluated by visual observation outdoors where it was not exposed to direct sunlight. In addition, each of the obtained multilayer coating films was MA-68II (trade name, multi-angle spectrophotometer,
Color measurement by X-Rite) to obtain IV representing the brightness of the highlight. Table 2 shows the results.

The metallic paint composition and 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)

0.1 to 50 parts by weight of the glitter pigment (A) having a particle size of 5 to 14 μm, in which the alumina flake base material is coated with titanium oxide with respect to 100 parts by weight of the vehicle-forming resin composition, and the alumina flake base material Blue interference color in which titanium oxide is coated on a bright pigment (B) having a particle diameter of 15 to 25 μm coated with titanium oxide and a scaly substrate selected from natural mica, artificial mica, silica flakes and glass flakes A metallic paint composition comprising an interference pearl pigment (C) that expresses a pigment, wherein the mass ratio of the glitter pigments (A) and (B) is 10/1 to 1/3 object. A method for forming a multi-layer coating film, wherein a top clear coating material is further applied onto a coating film obtained by applying the metallic coating composition according to claim 1 to an object to be coated . A method for forming a multi-layer coating film comprising applying a metallic paint composition in a plurality of stages, comprising:
The total content of the luster pigment contained in the metallic paint composition applied on the stage,
The ratio with the total content of glitter pigments contained in the metallic paint composition to be painted with
3. The method for forming a multilayer coating film according to claim 2, wherein the solid content is from 1 / 1.5 to 1/10 . A coating film structure obtained by the multilayer coating film forming method according to claim 2 . A coated article obtained by the method for forming a multilayer coating film according to claim 2 .