JP2015051385A - Method for forming multi-layered coating film and multi-layered coating film obtained by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-layered coating film which has a collar pearl coating color as a coating material for an automobile body, a week bluish interference color in a highlight part, and a weak yellow transparent color in a shade part, and keeps a color development with a color base coating film visible omnidirectionally.SOLUTION: A method for forming a multi-layered coating film, which includes the steps of: forming a color base coating film by coating a base material with a color base coating material containing a coloring pigment; forming a brilliant coating film by coating an obtained color base coating film with a brilliant coating material containing a coherent brilliant coating material and a titanium dioxide pigment; and forming a clear coating film by coating an obtained brilliant coating film with a clear coating material, makes volume cumulative particle diameters D90 and D50 of the titanium dioxide pigment that the brilliant coating film contains be in a predetermined range and restricts a mass ratio of the coherent brilliant pigment to the titanium dioxide pigment in a coating material solid of the coherent brilliant coating material.

Description

  The present invention relates to a method for forming a multilayer coating film capable of obtaining a pearly coating color, a multilayer coating film obtained therefrom, and the formation of a multilayer coating film having an excellent heat shielding effect in addition to the pearly coating color. The present invention relates to a method and a multilayer coating film obtained therefrom.

  In recent years, in the field of automobile painting, coating films having high design properties have been developed. This is because consumers tend to prefer a paint color with a sense of brightness and a sense of luxury rather than a so-called solid color. Further, this is because there is a tendency to seek a more unique design such as an interference texture whose hue changes depending on the viewing angle, as well as a mere glitter. For example, a pearl-tone multi-layer coating film utilizing interference color change due to the thickness of mica such as interference mica pigment has been developed. Specifically, multi-layer coatings (commonly known as white pearl mica coatings), in which an interference coating containing an interference mica pigment is formed on a white base coating, are known as high-quality coatings. ing. However, even these coatings are not new to consumers, and there is a demand for new design coatings with further design properties in the field, and application to color base coatings is required. Is desired.

  Examples of the luster pigment used for the pearl tone coating color include an interference type mica pigment. This interference-based mica pigment is a coating of metal oxide on mica flakes or alumina flakes, and causes interference of light at the coating part, resulting in a pearly color development due to the color change due to interference on the flickering feeling of the flake pigment . However, there is a problem that interference of light also causes unnecessary color development. For example, when an interference-type mica pigment is used in a white coating film, the highlight portion (when viewed from the front) looks bluish white, and the shade portion (when the coating is viewed from an oblique direction). Then it looks yellowish white.

  In addition, when a light-colored colored coating film, that is, a colored coating film having a relatively high brightness, is combined with a glittering coating film containing an interference glittering pigment to form a multi-layered coating film of color pearl tone, Similar to the film, unnecessary coloring due to the interference bright pigment is visible, and there is a problem that the original design of the color pearl tone coating film cannot be obtained depending on the viewing angle. Especially when painted on a substrate with a curved surface such as the body of an automobile, the highlight and shade parts can be seen at the same time even when viewed from one direction. In this case, the above-mentioned unnecessary color formation in the highlight and shade portions is a serious problem, and a color pearl tone coating color that suppresses such unnecessary color formation and allows a relatively high brightness light color in all directions is desired. Yes.

  Japanese Patent Application Laid-Open No. 2001-327916 (Patent Document 1) discloses that the lightness of the color base coating film is 20 to 60 in terms of L value, and a glittering paint (the glittering pigment is mica) that forms the mica base coating film. ) Contains titanium dioxide-coated silica flakes in a pigment concentration (PWC) in the range of 1 to 10%. A method for forming a multilayer pearl coating film is disclosed. This invention can suppress yellowness when viewed from the shade position by blending a predetermined amount of titanium dioxide-coated silica flakes in a coating film containing an interference type mica pigment.

  However, in the method for forming a multi-layer pearl coating film described in Patent Document 1, blue interference remains when viewed from the highlight portion even though yellowness in the shade portion can be suppressed, and the color base in all directions. It was not possible to obtain a multi-layered pearl coating film in which the color development due to was observed.

By the way, since the building roots and building exteriors and buildings are always exposed to sunlight, it is proposed to use paints with high infrared reflectivity (thermal barrier paints) when it is desired to suppress temperature rise. ing.

  Even in the automobile body, it may be desired to apply a heat-shielding paint to reduce the temperature rise in the car, but when applying to an automobile body, it is necessary to apply a thin film thickness and to the automobile body. It is necessary to satisfy both the required high design properties and heat shielding properties.

  As a thermal barrier coating material for automobile bodies, a low-luminance thermal barrier coating material having a lightness L value of 20 to 40 using subtractive color mixing has been proposed (Patent Document 2). However, a method for solving the above-mentioned problem of the design characteristic peculiar to the medium-lightness pearl-tone coating color and obtaining a heat shielding effect has not been studied for a medium-lightness pearl-tone coating color having an L value of 40 or more.

JP 2001-327916 A JP 2009-286862 A

  In the present invention, when a glittering coating film is formed on a colored base coating film to form a multi-layer coating film of a color pearl tone, there is little bluish interference in the highlight area, and the yellow transmitted color is weak in the shade area. Another object of the present invention is to provide a method for forming a multi-layer coating film having a color pearl tone coating color in which the coloration by the base coating film can be seen well in all directions, and the glittering color of the glittering pigment and the pearl coloration can be maintained.

It is another object of the present invention to provide a method of forming a multi-layer coating film having a color pearl tone coating color that is excellent in heat shielding effect by coloring the color base coating film by subtractive color mixing of color pigments.

An object of the present invention is to provide a method for forming a multilayer coating film that is further excellent in heat shielding effect by containing titanium dioxide having a predetermined particle size distribution in the glitter coating composition and / or colored base coating composition. To do. In addition, as a heat-shielding effect here, it means that solar radiation reflectance, especially infrared reflectance are high.

  That is, the present invention comprises a step (1) of forming a color base coating film by applying a color base paint containing a color pigment on a substrate, and an interference bright pigment and a titanium dioxide pigment on the obtained color base coating film. A multilayer including a step (2) of forming a glittering coating film by applying the glittering coating material, and a step (3) of forming a clear coating film by applying the clear coating material on the resulting glittering coating film. A method for forming a coating film, wherein the titanium dioxide pigment contained in the glitter paint has a volume cumulative particle diameter D90 of 700 to 1200 nm, a volume cumulative particle diameter D50 of 250 to 900 nm, and the glitter Formation of a multilayer coating film in which the mass ratio of the interference bright pigment and the titanium dioxide pigment in the paint solid content of the conductive paint is interference bright pigment / titanium dioxide pigment = 10/1 to 5/1 Provide a method.

  The color base paint is preferably colored by subtractive color mixing of the color pigments.

  The lightness of the color base coating film is preferably 20 or more and less than 80 in terms of L value.

  The lightness of the multilayer coating film is preferably 20 or more and less than 85 in terms of L value.

  The titanium dioxide pigment contained in the glitter paint preferably has a primary particle volume average particle size of 200 to 2000 nm.

  The titanium dioxide pigment contained in the color base paint preferably has a primary particle volume average particle size of 200 to 2000 nm.

  The titanium dioxide pigment contained in the color base paint has a volume cumulative particle diameter D90 of 650 to 2000 nm and a volume cumulative particle diameter D50 of 140 to 1100 nm.

  The present invention also provides a multilayer coating film obtained by the above-described method for forming a multilayer coating film.

  According to the present invention, as a method for obtaining a color pearl-tone multi-layer coating film by combining a color base coating film with a glittering coating film containing an interference glittering pigment, the glitter coating containing the interference glittering pigment is used. When titanium dioxide having a volume cumulative particle diameter D90 of 700 to 1200 nm and a volume cumulative particle diameter D50 of 250 to 900 nm is blended with the glittering paint forming the film, the color base coating film is blue in the highlight area. Color pearl-colored multi-layer coating with weak taste interference, weak yellow transmission color even in shade areas, good color development by color base coating in all directions, and maintaining the glitter and pearl color of glittering pigments A membrane can be obtained. For this reason, according to the present invention, it is possible to obtain an excellent color pearl coating color even in a relatively high brightness region (the L value of the multilayer coating film is 20 or more and less than 85). Can satisfy the request.

  The mechanism for suppressing unnecessary color development in the present invention is not limited to a specific theory, but is related to the particle diameter of the titanium dioxide pigment in the glitter coating film, and many have a small particle diameter of the titanium dioxide pigment. In the case of the particle size distribution, the titanium dioxide having a small particle size itself has a bluish color, so that the bluish color in the highlight portion cannot be erased. By using titanium dioxide with a particle size distribution, it is possible to moderately block unwanted interference colors due to the interference bright pigment while maintaining the pearl color development, so the pearl system does not feel the bluishness in the highlight area. It is considered that it is possible to obtain the color of the color, and it is considered that the shade of yellow can be suppressed in the shade part. In other words, the presence of titanium dioxide having such a particle size distribution makes it possible to feel the blue interference color in the highlight area and the yellow transmission color in the shade area without impairing the pearl coloration from the glitter coating. It can be suppressed to the extent that it does not occur, and the original pearl-based color can be obtained.

Moreover, the thermal insulation effect of the obtained multilayer coating film can be improved by making the said color base coating film colored by the subtractive color mixture of a color pigment.
Furthermore, the thermal barrier effect of the obtained multilayer coating film can be improved by containing titanium dioxide having a predetermined particle size distribution in the glittering paint and / or the colored base paint.

  The method for forming a multi-layer coating film of the present invention comprises a step (1) of forming a color base coating film by applying a color base paint containing a titanium dioxide pigment and a color pigment on a substrate, and the obtained color base coating film. A step (2) of forming a glittering paint film by applying a glittering paint containing an interference glittering pigment and a titanium dioxide pigment, and applying a clear paint on the resulting glittering paint film to form a clear paint film It consists of three processes including the process (3) to form. Each will be explained.

Process (1)
The first step of the present invention is a step of applying a color base paint containing a titanium dioxide pigment and a color pigment on a substrate to form a color base coating film.

Substrate In the method for forming a multilayer coating film of the present invention, the substrate is not particularly limited. For example, it can be advantageously used for metals, glass, plastics, foams, etc., particularly metal surfaces, and castings. Paintable metal products are preferred.

  Examples of the metal products include iron, copper, aluminum, tin, zinc and the like and alloys containing these metals. Specific examples include automobile bodies and parts such as passenger cars, trucks, motorcycles, and buses. These metals are preferably those that have been previously subjected to chemical conversion treatment with a phosphate, chromate, zirconium compound, etc., and those having a cationic electrodeposition coating film.

Color Base Coating Film In the multilayer coating film forming method of the present invention, step (1) is to form a color base coating film by applying a color base paint containing a color pigment on a substrate. The color base paint also has a function of concealing the underlying color and preventing light from passing therethrough. If the background is poor and light transmission cannot be suppressed, the same color base paint may be applied twice or may be baked for each application. In this case, the first color base coating film may be changed to a base coating film having an L value of 20 to 60.

  Since the color base paint of the present invention contains a color pigment, the color base coating film obtained by applying the color base paint is colored.

  The color base coating film of the present invention preferably has an L value of less than 80 in order to obtain a color pearl-tone multilayer coating film. The L value is a value representing the lightness of the L * a * b * color system in the method of measuring color. When the L value is high, it is bright, normally white has the highest L value, low L value is dark, and black has the lowest L value. In the present invention, the L value is the brightness in the highlight direction. As the brightness L value in the highlight direction, for example, the L25 value measured by illuminating from 25 ° and receiving light at the front (0 °) corresponds to the multi-angle spectroscopic colorimeter CM512m-3 manufactured by Konica Minolta. Can be measured. In this specification, “L value” means the L25 value.

In the present invention, when the L value of the color base coating film is 80 or more, a white base is obtained, and the resulting multilayer coating film is a white pearl-like multilayer coating film, so that a color pearl multilayer coating film is obtained. In addition, the L value is preferably less than 80. Further, by setting the lightness of the color base coating film to an L value of less than 80, the lightness of a multilayer coating film using the color base coating film can be set to an L value of less than 85. Can be obtained even more.

In addition, when the L value of the color base coating film is less than 20, it becomes a dark color close to black. Therefore, when a multi-layer coating film with a pearl tone color is formed in combination with a glitter coating film containing an interference glitter pigment. Even if there is unnecessary color development in the highlight portion or shade portion, it is difficult to cause a problem because it is lost in the dark color. Therefore, in the present invention, the color base coating film preferably has a lightness of L value of 20 or more and less than 80, and more preferably 40 or more and less than 80 for the same reason. Therefore, when the L value of the color base coating film is 20 or more and less than 80, the blue interference in the unnecessary highlight portion and the yellow interference in the shade portion that occur when the multilayer coating film is formed, It can suppress by using the formation method of the multilayer coating film of this invention.

In addition, although the color base coating film prescribes | regulates the preferable brightness in the range of L value, control of hues other than the brightness can be easily performed within the range of L value.

The color base paint of the present invention contains a color pigment and can be colored by subtractive color mixing of the color pigment. As long as the color pigment is a color pigment that can be used for subtractive color mixing, various pigments that are usually used in paints can be used.

By using the color pigment in the color base paint, the color base paint film obtained by applying the paint is colored by subtractive color mixture. As a result, the multilayer paint film of the present invention has a design property. In addition to an excellent color pearl-tone multi-layer coating film, the heat shielding effect is improved. Here, subtractive color mixing refers to a color mixing method in which lightness is reduced by mixing cyan, magenta, and / or yellow having the property of absorbing a certain range of wavelengths when mixed. In the present invention, such coloring pigments include not only cyan, magenta, and yellow pigments, but also purple, blue, red, and cyan, magenta, and yellow by mixing two or more. Those selected from green and yellow pigments can also be used. Specifically, purple pigments such as dioxazine violet, red pigments such as iron oxide red, Shannin green green pigments, Shannin blue blue pigments, and cocopal yellow yellows And pigments.

In the present invention, coloring by subtractive color mixing includes not only the case of an achromatic color but also the case of a chromatic color. In the case of a chromatic color, in addition to lowering the lightness by subtractive color mixing, it is adjusted by imparting a hue with the colored pigment. In this case, only the color pigment used for the subtractive color mixture may be used, or in addition to the color pigment used for the subtractive color mixture, titanium dioxide may be used as a color pigment other than these, for example, a white pigment. Black pigments can be used as pigments other than the color pigments used for subtractive color mixing, but carbon black is extremely limited in heat-shielding effect, so even if it is used, it is limited to a very small amount.

In the multilayer coating film of the present invention, by using a color base coating film colored by subtractive color mixture, the heat-shielding effect of the multilayer coating film can be improved, and a color pearl tone multilayer coating film can be formed by the coloring. Can be obtained.

By using a color base coating film colored by subtractive color mixing, the effect of improving the heat shielding effect of the multilayer coating film can reduce the brightness of the color base coating film without using carbon black in the color base coating material. As a result, the brightness of the multilayer coating film of the present invention using the color base coating film can be lowered.

  When a titanium dioxide pigment is used as a white pigment in the color base paint, the titanium dioxide is not particularly limited, and examples thereof include normal titanium dioxide. In order to enhance the heat shielding effect of the resulting multilayer coating film, it is preferable to use titanium dioxide having a primary particle volume average particle diameter of 200 to 2000 nm, and more preferably 250 to 1600 nm. The volume average particle diameter of the primary particles can be measured by a dynamic light scattering method. More specifically, it can be measured using UPA-150 (particle size distribution measuring device manufactured by Microtrac) or an electron microscope. Examples of commercially available products include TITANIX JR-1000 (manufactured by Teika, volume-average particle diameter of primary particles 800 nm) and Type CR-95 (manufactured by Ishihara Sangyo Co., Ltd., volume-average particle diameter of primary particles 250 nm).

  The titanium dioxide pigment contained in the color base paint preferably has a volume cumulative particle diameter D90 of 650 to 2000 nm and a volume cumulative particle diameter D50 of 140 to 1100 nm. When the volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the color base paint are controlled within this range, a heat shielding effect can be imparted to the resulting coating film. The titanium dioxide pigment content in the color base paint is 30 to 75% by mass in terms of the solid content of the paint.

Here, the volume cumulative particle diameter D90 is the total particle volume integrated from the small particle diameter side to a certain particle diameter in the particle size distribution of the titanium dioxide pigment, expressed as a percentage of the total particle volume. The particle diameter when the value is 90%, and the volume cumulative particle diameter D50 is the particle diameter when the percentage value is 50%. The volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 are measured using a dynamic light scattering method, particularly UPA-150 (a particle size distribution measuring device manufactured by Microtrack). The same applies to the volume cumulative particle diameter D50 and the volume cumulative particle diameter D90 relating to the titanium dioxide pigment in the glitter paint described later.

  The titanium dioxide pigment has a volume cumulative particle diameter D90 of 650 to 2000 nm, preferably 700 to 1300 nm, and more preferably 700 to 1200 nm. When the volume cumulative particle diameter D90 is less than 650 nm, the heat shielding effect cannot be obtained. On the other hand, when the volume cumulative particle diameter D90 exceeds 2000 nm, the gloss and appearance of the coating film deteriorate.

  The titanium dioxide pigment has a volume cumulative particle diameter D50 of 140 to 1100 nm, preferably 160 to 1000 nm, and more preferably 250 to 900 nm. When the volume cumulative particle diameter D50 is less than 140 nm, the heat shielding effect is lowered. On the other hand, when the volume cumulative particle diameter D50 is more than 1100 nm, the base concealing property is remarkably deteriorated and a transparent coating film is formed.

The color pigment contained in the color base paint is a pigment based on the total mass of all resin components and all pigments contained in the glitter paint composition. The color pigment contained in the color base paint in the color base paint is a color base paint composition. The pigment mass concentration (PWC) with respect to the total amount of all the binder components and all the pigments contained in is preferably 0.1% to 30%, more preferably 0.1 to 20% by mass.

Especially, as titanium dioxide, in order to acquire a heat-shielding effect, it is preferable that the titanium dioxide whose primary particle volume average particle diameter is 200-2000 nm is 0.01-1.00% as PWC.

Binder Component The color base paint contains a film-forming resin as a binder component in addition to the color pigment. Examples of the coating film-forming resin include acrylic resin, polyester resin, alkyd resin, and fluorine resin. The binder component contains a curing agent as necessary. Examples of the curing agent include amino resins and / or block polyisocyanate compounds. The solid content of the binder component contained in the color base coating is preferably 30 to 70% by mass with respect to the entire coating composition when the coating composition is produced, and in the range of 10 to 50% by mass when applied. Preferably there is.

  Furthermore, the color base coating material can contain other additives well known by those skilled in the art in addition to the color pigment and the binder component. Examples of such additives include surface conditioners such as silicone and organic polymers, curing catalysts, ultraviolet absorbers, hindered amines, hindered phenols, and the like. These compounding amounts are within the range known to those skilled in the art. The paint form of the color base paint is not particularly limited, and specific examples include an organic solvent type, an aqueous type (water-soluble, water-dispersible, emulsion), and a non-aqueous dispersion type.

  In the above step (1), the method for applying the color base paint on the substrate is not particularly limited, and multistage coating by air electrostatic spray coating, preferably two-stage coating, is performed in order to improve the design. , A coating method that combines air electrostatic spray coating with a rotary atomizing electrostatic coating machine called “μμ (micro) bell”, “μ (micro) bell” or “metabell” Can be mentioned. Paint a color base paint on the substrate.

  The coating thickness of the color base paint by the coating method is not limited because it varies depending on the application, but is, for example, 10 to 50 μm in terms of dry thickness. If the thickness exceeds 50 μm, the sharpness may be deteriorated, or defects such as unevenness, flaming, and sagging may occur during coating. If the thickness is less than 10 μm, the substrate cannot be concealed and the film is broken.

  The color base coating film obtained by the step (1) may be cured before the step (2) or may not be cured. After application, the temperature and time for curing the color base coating film can be appropriately set depending on the binder component contained in the color base paint, but it is usually 120 to 160 ° C. for 10 to 30 minutes. In addition, when a color base coating material is a water-based coating material, even when it is not hardened | cured, you may dry the color base coating film obtained in order to remove water after application | coating for 1 to 10 minutes, for example at 20-80 degreeC. By doing so, the smoothness and design of the finally obtained multilayer coating film can be improved.

Process (2)
The second step of the present invention is a step of forming a glittering coating film by applying a glittering paint containing an interference glittering pigment and a titanium dioxide pigment on the color base coating film obtained in the step (1). is there.

Interfering bright pigment The interference bright pigment contained in the above-mentioned bright paint is usually used for pearl paint, and is selected from the group consisting of mica flakes, silica flakes, alumina flakes and glass flakes. The thing which the coating layer of the metal oxide was provided in the surface of the base material more than a seed | species can be mentioned. From the viewpoint of particle feeling, an alumina flake pigment whose surface is coated with a metal oxide such as TiO ₂ and their hydrates is preferable. The shape of the interfering bright pigment is not particularly limited. For example, if the pigment has a scaly shape, a volume cumulative particle diameter D50 of 2 to 50 μm and a thickness of 0.1 to 3 μm are suitable. ing.

  D50 is a volume cumulative particle diameter, and is measured by a dynamic light scattering method. More specifically, it can be measured with UPA-150 (a particle size distribution measuring device manufactured by Microtrac).

  The above-mentioned interference glittering pigments are commercially available, SILALIC T60-10 WNT (Merck Japan Co., Ltd. interference alumina flake pigment), SILALIC T60-23 WNT (Merck Japan Co., Ltd. interference alumina flake pigment) and Pearl Glaze SME 90. -9 (manufactured by Nippon Koken Co., Ltd., mica-based pearl pigment), Metashine MC1020RSJA1 (manufactured by Nippon Sheet Glass Co., Ltd.) and the like are preferably used from the viewpoint of imparting a sparkling stereoscopic effect.

Titanium dioxide pigment The titanium dioxide pigment contained in the glittering paint of the present invention has primary particle and / or secondary particle having a specific particle size distribution, and the specific particle size distribution is a volume cumulative particle size D90. And D50. That is, the titanium dioxide pigment needs to have a volume cumulative particle diameter D90 of 700 to 1200 nm and a volume cumulative particle diameter D50 of 250 to 900 nm in the glittering paint. Volume cumulative particle diameter D90 and volume cumulative

Since the multi-layer coating film of the present invention contains a titanium dioxide pigment having a specific particle size distribution in the glitter coating film, it is unnecessary to observe with the pearl tone coloration by the interference glitter pigment. Blue color in the highlight area and yellow color in the shade area can be suppressed, the original color of pearl tone can be obtained, the color developed by the base film can be seen well in all directions, and the coherent glitter It is possible to obtain a multi-layer coating film with a color pearly tone with a distinctly high radiance feeling by virtue of the pigment and pearl tone coloration.

  The titanium dioxide pigment has a volume cumulative particle diameter D90 of 700 to 1200 nm, preferably 800 to 1100 nm, and more preferably 900 to 1000 nm. When the volume cumulative particle diameter D90 is less than 700 nm, the effect of suppressing unnecessary color development of the coherent bright pigment becomes insufficient. On the other hand, when the volume cumulative particle diameter D90 exceeds 1200 nm, the gloss of the resulting coating film decreases.

  The titanium dioxide pigment has a volume cumulative particle diameter D50 of 250 to 900 nm, preferably 270 to 800 nm, and more preferably 300 to 700 nm. When the volume cumulative particle diameter D50 is less than 250 nm, the concealing property of the obtained coating film is lowered, and when it exceeds 900 nm, the design property due to the coloring of the interference bright pigment is lowered.

  In the titanium dioxide pigment, the primary particles preferably have a volume average particle diameter of 200 to 2000 nm, preferably 250 to 1600 nm, from the viewpoint of achieving both the resulting gloss and the effect of suppressing the complementary color of the interference bright pigment. More preferably. Further, from the viewpoint of obtaining a heat shielding effect, the volume average particle diameter of the primary particles of the titanium dioxide pigment is preferably 200 to 2000 nm, and more preferably 250 to 1600 nm. The volume average particle diameter of the primary particles can be measured by a dynamic light scattering method. More specifically, it can be measured using UPA-150 (particle size distribution measuring device manufactured by Microtrac) or an electron microscope.

  Titanium dioxide pigments whose primary particles have a volume average particle size of 200 to 2000 nm are commercially available, such as TITANIX JR-1000 (manufactured by Teika, volume average particle size of primary particles of 800 nm), and Taipei CR-95 (Ishihara Sangyo Co., Ltd.). Manufactured, volume average particle diameter of primary particles 250 nm). Of course, it is not limited to these.

  The glitter paint includes two kinds of the interference glitter pigment and the titanium dioxide pigment. The mass ratio of the interference bright pigment and the titanium dioxide pigment is 10/1 to 5/1, preferably 10/1 to 6/1, as the ratio of the interference bright pigment / titanium dioxide pigment. . When the amount of the interfering bright pigment is larger than 10/1 at the above mass ratio, the finished appearance of the resulting coating film is deteriorated. When the amount of the interference bright pigment is smaller than 5/1, the glitter feeling is lost and the interference bright pigment is used. Design properties due to color development deteriorate.

  The interference glittering pigment contained in the glittering paint is preferably 1 to 30% by mass in terms of pigment mass concentration (PWC) with respect to the total amount of all resin components and all pigments contained in the glittering paint composition. More preferably, the amount is ˜25% by mass. Moreover, 0.1-5 mass% is preferable in titanium dioxide contained in the said glittering coating material by PWC, and it is more preferable that it is 0.1-4 mass%. The total amount of the interfering bright pigment and the titanium dioxide pigment contained in the bright paint is preferably 1.1 to 35% by mass and more preferably 1.1 to 30% by mass in terms of PWC.

Binder Component The glitter paint of the present invention contains a film-forming resin as a binder component in addition to the interference glitter pigment and titanium dioxide pigment. As the coating film-forming resin, the same resin as described for the color base paint can be used. The solid content of the binder component contained in the glitter paint is 30 to 70% by mass with respect to the whole paint when the paint is produced, and preferably 10 to 50% by mass when applied.

Other components In addition to the above-mentioned interference bright pigment, titanium dioxide pigment and binder component, a viscosity control agent can generally be added to the bright paint used in the present invention in order to ensure coating workability. . As the above-mentioned viscosity control agent, those generally showing thixotropy can be used. Polyethylene-based materials such as dispersions, organic bentonite-based materials such as organic acid smectite clay, montmorillonite, inorganic pigments such as aluminum silicate and barium sulfate, flat pigments that develop viscosity depending on the shape of the pigment, cross-linked or non-cross-linked Resin particles and the like.

  Further, the glittering paint can contain other additives as desired. Examples of such additives include surface conditioners such as silicone and organic polymers, curing catalysts, ultraviolet absorbers, hindered amines, hindered phenols, and the like. These compounding amounts are within the range known to those skilled in the art.

  If desired, the glitter paint can contain a glitter pigment other than the interference glitter pigment. The total amount of glitter pigments other than the interference glitter pigment and the interference glitter pigment contained in the glitter paint is preferably 1 to 50% by mass and 1 to 40% by mass in terms of PWC. More preferred. Examples of the bright pigment other than the interference bright pigment include aluminum flakes, colored aluminum flakes, glass flakes, hologram pigments, and liquid crystal polymer pigments.

If desired, the glitter paint can contain a color pigment. Examples of the color pigment include violet, blue, red, green, and yellow pigments. The heat shielding effect can be enhanced by using two or more kinds of color pigments whose brightness can be adjusted by subtractive color mixing as the color pigments. The PWC of the color pigment is preferably 0.1 to 30% by mass, and more preferably 0.1 to 20% by mass. Examples of extender pigments include talc, calcined kaolin, calcium carbonate, barium sulfate, and magnesium silicate. The PWC of the extender pigment is preferably 25 to 60% by mass, and more preferably 30 to 50% by mass.

  The form of the glittering paint is not particularly limited, and any of an organic solvent type, an aqueous type (water-soluble, water-dispersible, emulsion), and a non-aqueous dispersion type may be used.

  The glitter paint is prepared by mixing and dispersing the interference glitter pigment and other glitter pigments, titanium dioxide pigment, binder component, viscosity controlling agent and other components.

  What is important when preparing the glitter paint is that the mass ratio of the interfering glitter pigment and the titanium dioxide pigment contained, the volume cumulative particle diameter D90 of the titanium dioxide pigment to be dispersed, and the volume cumulative particles. This is control of the diameter D50.

  In particular, the volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment are the most important, and can be controlled by adjusting, for example, the media used for dispersion and the dispersion time when preparing the coating material. it can. Moreover, it can adjust by mixing the titanium dioxide pigment which has a 2 or more types of different particle size distribution, or can adjust by classification etc. From the viewpoint of controlling the volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment, the titanium dioxide pigment is separately mixed and dispersed with a coating material such as a dispersant, a dispersion resin and / or a binder resin. After preparing a titanium dioxide pigment paste in advance, it is preferable to prepare the glitter paint by mixing and dispersing with other components.

  In the multilayer coating film forming method of the present invention, in step (2), a glittering coating film is formed by applying a glittering paint on the color base coating film obtained in the above step (1). The glitter paint is formed in order to express a design such as a glitter feeling and a pearl interference color in the multilayer coating film obtained from the transmitted light and the reflected light from the color base coating film.

The conditions relating to the coating method and the processing method for the glitter coating after coating are the same as the conditions for the coating method and processing method for the color base coating film in the step (1). However, the coating film thickness is preferably 10 to 30 μm in terms of dry film thickness.

Step (3)
In the method for forming a multilayer coating film of the present invention, the factory (3) applies a clear coating onto the glitter coating obtained in the step (2) to form a clear coating.

  The clear coating contains a film-forming resin and a curing agent. The coating film-forming resin and the curing agent used for the clear coating are not particularly limited, and examples thereof include those described in the above color base coating. In addition, from the viewpoint of transparency or acid resistance of the obtained coating film, a combination of an acrylic resin and / or a polyester resin and an amino resin, an acrylic resin and / or a polyester resin having a carboxylic acid / epoxy curing system, etc. It is done. In the case of a urethane-based clear paint, either a one-component type or a two-component type may be used.

  Further, the clear paint can contain other additives as in the color base paint. In particular, it is preferable to contain a viscosity control agent in order to prevent mixed layer, inversion or sagging between the titanium dioxide coating and the resulting clear coating. The content of the viscosity control agent with respect to 100 parts by mass of the resin solid content contained in the clear coating is 0.01 to 10 parts by mass, preferably 0.02 to 8 parts by mass, and 0.03 to 6 parts by mass. More preferred. When the solid content exceeds 10 parts by mass, the appearance is deteriorated. When the solids content is less than 0.01 parts by mass, the viscosity control effect cannot be obtained, which causes problems such as sagging.

  The form of the clear paint is not particularly limited. Like the color base paint, an organic solvent type, an aqueous type (water-soluble, water-dispersible, emulsion), a non-aqueous dispersion type, a powder type, a slurry type, etc. Can be mentioned.

  The solid content of the clear coating is not particularly limited, and is, for example, 20 to 60% by mass, preferably 35 to 55% by mass. Moreover, solid content at the time of application | coating is 10-50 mass%, Preferably it is 20-50 mass%.

  Examples of the coating method include those described for the color base paint. The coating film thickness of the clear coating by the above coating method is not limited because it varies depending on the application, but is, for example, 10 to 70 μm in dry film thickness.

  After applying the clear paint, the resulting clear coating is cured. The curing temperature and the curing time can be appropriately set depending on the binder component contained in the clear coating, and are, for example, 120 to 160 ° C. and 10 to 30 minutes. In addition, when the said clear coating material uses a urethane type clear coating material, hardening temperature and hardening time can be set to 10 to 30 minutes at 60-120 degreeC, for example.

  The dry film thickness of the multilayer coating film formed by the multilayer coating film forming method of the present invention is 30 to 300 μm, and preferably 50 to 250 μm. If the dry film thickness of the multilayer coating film is less than 30 μm, the strength of the coating film itself may be reduced, and if the dry film thickness of the multilayer coating film exceeds 300 μm, film properties such as a cooling cycle are deteriorated.

  The lightness L value of the multilayer coating film formed by the multilayer coating film forming method of the present invention is 20 or more and less than 85 when the brightness of the color base coating film used is 20 or more and less than 80. Here, the lightness L value of the multi-layer coating film is a value representing the lightness of the L * a * b * color system of the method of measuring the color, similar to the L value of the color base coating film. This corresponds to the brightness in the highlight direction. As the brightness L value in the highlight direction of the multilayer coating film, for example, the L25 value measured by illuminating from 25 ° and receiving light at the front (0 °) corresponds to the multi-angle spectral side color manufactured by Konica Minolta. The total CM512m-3 can be measured.

  When the lightness L value of the multi-layer coating film is 85 or more, a white pearl tone is obtained and a color pearl tone is not obtained. On the other hand, when the lightness L value of the multilayer coating film is less than 20, since the color base coating film and / or the glitter coating film are dark, the blue interference color in the highlight portion and the yellow transmission in the shade portion. Even if there is a color, it will not be a problem because it will be lost in the dark color.

  On the other hand, when the lightness of the multi-layer coating film is 20 or more and less than 85, the multi-layer coating film becomes a light colored color pearl tone coating color, but unnecessary color development in the highlight portion and shade portion is suppressed. The original design color of pearl tone paint color can be obtained.

  As described above, the multilayer coating film of the present invention is obtained by the above-described multilayer coating film forming method. The multilayer coating film is different from the multilayer coating film using a conventional interference glittering pigment, and the titanium dioxide pigment having a specific particle size distribution existing in the glittering coating film is used to make the glitter pigment. Among the pearl-based designs that develop color, it is possible to suppress the bluish color in the highlight area and the yellow color in the shade area, resulting in the original color development of the pearl system, and the outstanding brightness of the color base color. A feeling can be obtained.

  Further, by coloring the color base coating film by subtractive color mixing of color pigments, in addition to such a design effect, an excellent heat shielding effect can be obtained. Furthermore, an excellent heat shielding effect is exhibited by containing titanium dioxide having a specific particle size and / or particle size distribution in the glitter coating and color base coating.

  The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Creating paints to use
Color base paint 1 (gray)
The color base paint shown in Table 1 was added to 51.0 parts by mass of thermosetting polyester resin (manufactured by Nippon Paint Co., Ltd., solid content acid value 8 mgKOH / g, hydroxyl value 80 mgKOH / g, number average molecular weight 1,800, solid content 70% by mass). TITANIX JR-1000 described in the column 1 (Titanium dioxide manufactured by Teika Co., Ltd., volume average particle diameter of primary particles 800 nm) 25.0 parts by mass, Shanin blue 5240 KB (blue pigment commercially available from Dainichi Seika) 1.5 mass Parts, Lionol Green 6YKPN (green pigment commercially available from Toyo Ink Co., Ltd.) 0.1 parts by mass, Biferox 120NM (red pigment commercially available from LANXESS) 2.7 parts by mass, Tarox XLO (commercially available from Titanium Industry Co., Ltd.) Yellow pigment) 1.7 parts by mass and Hoster Palm Violet RLNF (purple pigment commercially available from Hoechst) Add a trace amount in the amount shown in Table 1 to uniformly disperse, and further add 25.5 parts by mass of Uban 128 (Mitsui Cytec Co., Ltd. melamine resin, solid content 60% by mass) to uniformly disperse the color base paint 1 Obtained. The volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the color base paint 1 were measured with UPA-150 (Microtrac particle size distribution measuring device), and were 1100 nm and 850 nm, respectively. . Moreover, the volume average particle diameter of the primary particles of the titanium dioxide pigment was 800 nm. Next, a single film (color base film 1) of the color base paint 1 was prepared by the following procedure, and its L value (L25 value) was measured with CM512m-3 (Spectrocolorimeter manufactured by Konica Minolta). there were. Further, the infrared reflectance and solar reflectance of the color base film 1 were measured. The results are listed in Table 1.

Production of color base film:
Spray the color base paint 1 on a polypropylene plate so that the dry film thickness is 30 μm, heat and cure at 140 ° C. for 30 minutes using a dryer, cut with a knife, lift with tweezers, etc., and peel off. A color base film 1 was produced.

Measurement of infrared reflectance and solar reflectance of single film (color film 1) of color base paint 1 Infrared reflectance (%):
Infrared reflectance (wavelength 780 to 2500 nm) and solar reflectance (wavelength 300 to 2500 nm) were measured using a spectrophotometer U4100 manufactured by Hitachi High-Tech.

Measurement of L value of single film (color film 1) of color base paint 1 Using a multi-angle spectroscopic color meter CM512m-3 manufactured by Konica Minolta , it is measured by illuminating from 25 ° and receiving light at the front (0 °). The L25 value was measured.
Color base paint 2-8
A paint was prepared in the same manner as the color base paint 1 except that the combination of pigments shown in Table 1 below was used. The L value of the obtained color base paint single film, D90 and D50 of the titanium dioxide pigment used, and the infrared reflectance and solar reflectance were measured. The results are listed in Table 1.

Base paint A and B
A paint was prepared in the same manner as the color base paint 1 except that the combinations of pigments shown in the base paint A and the base paint B in Table 1 below were used. The L value of the single film of the obtained base paint, D90 and D50 of the titanium dioxide pigment used, and infrared reflectance and solar reflectance were measured. The results are listed in Table 1.

CR-95 titanium: Titanium dioxide pigment manufactured by Ishihara Sangyo Co., Ltd., volume average particle diameter of primary particles 250 nm
Shannin Blue 5205 Blue: Blue pigment commercially available from Dainichi Seika Co., Ltd. Shannin Green S: Green pigment commercially available from DIC Fastogen Super Red: Red pigment Sicotrans Yellow L-1100: Yellow pigment commercially available from BASF Carbon black MA-100: Mitsubishi Chemical

Bright paint 1
271.5 parts by mass of Nippon Paint's acrylic emulsion (volume average particle size 150 nm, nonvolatile content 20%, solid content acid value 20 mgKOH / g, hydroxyl value 40 mgKOH / g) and 10 parts by mass of dimethylethanolamine 10% by mass aqueous solution , 27.4 parts by mass of water-soluble acrylic resin (non-volatile content: 30.0% by mass, solid content acid value: 40 mgKOH / g, hydroxyl value: 50 mgKOH / g), Prime Pol PX-1000 (Sanyo Kasei Kogyo Co., Ltd.) 7.2 parts by mass of polyether polyol (non-volatile content 100%), 28.2 parts by mass of Cymel 204 (mixed alkylated melamine resin, 100% non-volatile content manufactured by Mitsui Cytec Co., Ltd.), and lauryl acid phosphate 0 .2 parts by mass, silicic T60-23WNT (Merck's interference blue alumina Lake pigment) 4.0 parts by mass, Silical T60-10WNT (Merck's interference alumina flake pigment) 4.0 parts by mass and Type CR-95 (Ishihara Sangyo Titanium dioxide pigment, primary particle volume average particle size 250 nm) ) 1.0 part by mass was added to the container and dispersed with glass beads for 180 minutes to obtain a glittering paint 1 having a mass ratio of glittering pigment / titanium dioxide of 8/1. When the volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the glitter paint 1 were measured with UPA-150 (particle size distribution measuring device manufactured by Microtrac), they were 900 nm and 300 nm, respectively. It was. The paint formulation is shown in Table 2.

Bright paint 2
A glittering paint 2 was obtained in the same manner as the glittering paint 1 except that TITANIX JR-1000 was used instead of Typaque CR-95. The volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the glittering paint 2 were 900 nm and 800 nm, respectively. The paint formulation is shown in Table 2.

Bright paint 3
A glittering paint 3 was obtained in the same manner as the glittering paint 1 except that TITANIX JR-1000 was used in place of the Taipei CR-95 and the dispersion time was 200 minutes. The volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the glittering paint 3 were 1000 nm and 600 nm, respectively. The paint formulation is shown in Table 2.

Bright paint 4
A brilliant paint 4 was obtained in the same manner as the brilliant paint 1 except that TITANIX JR-1000 was used instead of the typek CR-95 and the dispersion time was 220 minutes. The volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the glitter paint 4 were 900 nm and 500 nm, respectively. The paint formulation is shown in Table 2.

Bright paint 5
A glittering paint 5 was obtained in the same manner as the glittering paint 1 except that 0.8 parts by mass of Typaque CR-95 was used and the mass ratio of the interference bright pigment / titanium dioxide pigment was 10/1. The volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the glitter paint 5 were 900 nm and 300 nm, respectively. The paint formulation is shown in Table 2.

Bright paint 6
A glittering paint 6 was obtained in the same manner as the glittering paint 1 except that 1.2 parts by mass of Typaque CR-95 was used and the mass ratio of the interference brightening pigment / titanium dioxide pigment was 7/1. The volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the glittering paint 6 were 900 nm and 300 nm, respectively. The paint formulation is shown in Table 2.

Bright paint 7
A glittering paint 7 was obtained in the same manner as the glittering paint 1 except that the Taipei CR-97 was used instead of the Taipei CR-95. The volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the glitter paint 7 were 800 nm and 300 nm, respectively. The paint formulation is shown in Table 2.

Bright paint 8
A glittering paint 8 was obtained in the same manner as the glittering paint 1 except that the dispersion time was 120 minutes. The volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the glitter paint 8 were 1400 nm and 1000 nm, respectively. The paint formulation is shown in Table 2.

Bright paint 9
A glittering paint 9 was obtained in the same manner as the glittering paint 1 except that the dispersion time was 270 minutes. The volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the glittering paint 9 were 600 nm and 300 nm, respectively. The paint formulation is shown in Table 2.

Bright paint 10
A glittering paint 10 was obtained in the same manner as the glittering paint 5 except that the dispersion time was 270 minutes. The volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the glitter paint 10 were 700 nm and 150 nm, respectively. The paint formulation is shown in Table 1.

Bright paint 11
A glittering paint 11 was obtained in the same manner as the glittering paint 1 except that 2.0 parts by mass of Typaque CR-95 was used and the mass ratio of the interference glittering pigment / titanium dioxide pigment was 4/1. The paint formulation is shown in Table 2.

Bright paint 12
A glittering paint 12 was obtained in the same manner as the glittering paint 1 except that 0.5 parts by mass of Typaque CR-95 was used and the mass ratio of the interference bright pigment / titanium dioxide pigment was 16/1. The paint formulation is shown in Table 2.

Bright paint 13
A glittering paint 11 was obtained in the same manner as the glittering paint 1 except that no titanium dioxide pigment was blended. The paint formulation is shown in Table 2.

Bright paint 14
A glittering paint 14 was obtained in the same manner as the glittering paint 2 except that the dispersion time was 240 minutes. The volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the glittering paint 14 were 650 nm and 200 nm, respectively. The paint formulation is shown in Table 2.

Bright paint 15
A glittering paint 15 was obtained in the same manner as the glittering paint 2 except that the dispersion time was 140 minutes. The volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the glittering paint 15 were 1600 nm and 800 nm, respectively. The paint formulation is shown in Table 2.

Bright paint 16
A glittering paint 16 was obtained in the same manner as the glittering paint 2 except that the dispersion time was 100 minutes. The volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the glitter paint 16 were 1800 nm and 950 nm, respectively. The paint formulation is shown in Table 2.

Bright paint 17
A glittering paint 17 was obtained in the same manner as the glittering paint 2 except that the dispersion time was 210 minutes. The volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the glitter paint 17 were 1000 nm and 200 nm, respectively. The paint formulation is shown in Table 2.

Bright paint 18
A glittering paint 18 was obtained in the same manner as the glittering paint 2 except that the dispersion time was 160 minutes. The volume cumulative particle diameter D90 and the volume cumulative particle diameter D50 of the titanium dioxide pigment contained in the glitter paint 18 were 1000 nm and 950 nm, respectively. The paint formulation is shown in Table 2.

Clear paint 1
Macflow O-1820 clear (Nippon Paint Co., Ltd. carboxylic acid / epoxy curable clear paint) was used.

Example 1
(1) Preparation of test plate Powernics 110 (Cation Electrodeposition Paint manufactured by Nippon Paint Co., Ltd.) was applied to a 30 mm x 40 cm zinc dull steel plate treated with zinc phosphate so that the dry coating film would be 20 μm. After coating and heating and curing at 160 ° C. for 30 minutes, cooling was performed to form a cured electrodeposition coating film. The color base coating 1 was obtained by spray-coating the color base coating 1 on the above dull steel plate having a cured electrodeposition coating to a dry film thickness of 30 μm. Next, on the color base coating film 1 obtained, the glittering paint 1 was applied in one stage using a rotary atomizing electrostatic coating apparatus so as to have a dry film thickness of 15 μm. Thereafter, preheating was performed at 80 ° C. for 4 minutes.

  Next, on the resulting glittering coating film 1, the clear coating film 1 was applied in one stage using a rotary atomizing electrostatic coating apparatus so as to have a dry film thickness of 35 μm, whereby a clear coating film 1 was obtained. Thereafter, the obtained color base coating film 1, glitter coating film 1 and clear coating film 1 were heated and cured at 140 ° C. for 20 minutes at a time to obtain a test plate having a multilayer coating film.

(2) Evaluation Regarding the coating film appearance of the obtained test plate, the interference color (blue tint) in the highlight portion and the transmitted color (yellow tint) in the shade portion and the smoothness and design properties are as follows: Evaluation based on the criteria. Moreover, the infrared reflectance of the obtained test plate was measured. The results are shown in Table 3.

Colored state of interference color (blue tint) in highlights 3 A soft image with a faint blue tint.
2 A little blueness is visible.
1 Blueness looks weak.
0 Blueness looks very strong.

Colored state of the shade color (yellowishness) 3 The image with almost no yellowishness.
2 To the extent that yellowish color is visible.
1 The yellowness looks weak.
0 Yellowish color appears strong.

Smoothness ○: The coating film surface is smooth and smooth. ×: The coating film surface has large irregularities.

Design by coloring of interference bright pigment ○: Visible pearl-based color ×: Invisible pearl-based color

Infrared reflectance of multilayer coating film (%)
Infrared reflectivity (wavelength 800-2500 nm) was measured using a spectrophotometer U4100 manufactured by Hitachi High-Tech.
Measurement of L value of multilayer coating film Using a multi-angle spectroscopic color meter CM512m-3 manufactured by Konica Minolta, L25 value measured by illuminating from 25 ° and receiving light at the front (0 °) was measured.

Examples 2-17 and Comparative Examples 1-12
A test plate as in Example 1, except that the color base paint 1 is replaced with the color base paint described in the color base paint types in Table 3 and the glitter paint 1 is replaced with the glitter paint described in the bright paint types in Table 3. And the obtained test plate was evaluated in the same manner as in Example 1. The results are shown in Table 3.

  As is clear from the above Examples and Comparative Examples, in the multilayer coating films obtained in Examples 1 to 17, the interference color (blue tint) in the highlight portion is slightly visible or dull. The transmission color (yellowishness) in the shade portion is almost invisible or slightly visible, but the design based on the color of the color base paint and the design based on the color of the interference bright pigment It is good. At this time, the overall whiteness of the human eye is rather limited to the blueness (evaluation: 3) that can be blurred in the highlight area, or the blueness that is slightly visible (evaluation: 2 to 3). When the bluish color becomes a bluish color (evaluation: 1), the whiteness of the human eye does not stand out and the bluish color is felt.

  In Comparative Examples 1 to 3 and 7 to 12, either one of D90 and D50 or both D90 and D50 of the titanium dioxide pigment is outside the scope of the present invention. None of these comparative examples satisfy all of the pearl-based color development by the interference bright pigment, the interference color (blue tint) color development state of the highlight portion, and the transmission color (yellow tint) color development state of the shade portion. It was.

Comparative Examples 4 and 5 are cases in which the mass ratio of the interference bright pigment / titanium dioxide pigment is outside the scope of the present invention, and both the smoothness and the pearl coloration by the interference bright pigment are good, but highlights Unnecessary color development was strongly confirmed in the area and shade area. Comparative Example 6 is an example in which no titanium dioxide pigment is blended, but it is natural that the design by coloring the interference bright pigment is good, but the blueness in the highlight portion and the yellowness in the shade portion appear strong. . From the above, the design aspect of the present invention satisfies all the numerical ranges of D90 and D50 of the titanium dioxide pigment in the bright pigment in the present invention and the numerical range of the mass ratio of the interference bright pigment / titanium dioxide pigment. In other words, the blue-colored interference is weak in the highlight area, the yellow transmitted color is weak in the shade area, and the color-based coating color appears well in all directions, and the pearl-colored color due to the coherent bright pigment is observed. It can be seen that it is essential to obtain an effect on the design surface.

  The present invention is capable of obtaining a color pearl-tone coating color that varies in a vague color depending on the viewing angle and is difficult to see an interference color or a transmitted color, and forms a multilayer coating film having a heat shielding effect. Provide a method. In addition, when a color base coating composition is applied to a base material to form a color base coating film, and a glittering coating is applied to the color base coating film to form a multi-layer coating film, a color pearl color tone that is conspicuous in all directions is applied. Provided is a multilayer coating film which is colored and has an excellent heat shielding effect.

Claims (8)

  Step (1) of forming a color base paint film by applying a color base paint containing a color pigment on a substrate, and a glitter paint containing an interference bright pigment and a titanium dioxide pigment on the obtained color base paint film A method of forming a multi-layer coating film comprising a step (2) of forming a glittering coating film by coating, and a step (3) of forming a clear coating film by applying a clear coating on the resulting glittering coating film. The titanium dioxide pigment contained in the glitter paint has a volume cumulative particle diameter D90 of 700 to 1200 nm, a volume cumulative particle diameter D50 of 250 to 900 nm, and a paint solid content of the glitter paint. The method for forming a multi-layer coating film in which the mass ratio of the interfering bright pigment and the titanium dioxide pigment is: interference bright pigment / titanium dioxide pigment = 10/1 to 5/1.   The method for forming a multilayer coating film according to claim 1, wherein the color base paint is colored by subtractive color mixing of the color pigment.   The lightness of the said color base coating film is 20 or more and less than 80 in L value, The formation method of the multilayer coating film of Claim 1 or 2.   The lightness of the said multilayer coating film is 20 or more and less than 85 in L value, The formation method of the multilayer coating film in any one of Claims 1-3.   The method for forming a multilayer coating film according to any one of claims 1 to 3, wherein the titanium dioxide pigment contained in the glitter paint is titanium dioxide having a primary particle volume average particle diameter of 200 to 2000 nm.   The multi-layer coating according to any one of claims 1 to 5, wherein the color base paint contains a titanium dioxide pigment, and the titanium dioxide pigment is titanium dioxide having a volume average particle diameter of primary particles of 200 to 2000 nm. Method for forming a film.   The color base coating material contains a titanium dioxide pigment, and the titanium dioxide pigment has a volume cumulative particle diameter D90 of 650 to 2000 nm and a volume cumulative particle diameter D50 of 140 to 1100 nm. A method for forming a multilayer coating film according to claim 1.   The multilayer coating film obtained by the formation method of the multilayer coating film in any one of Claims 1-7.