JP2011025101A - Method of forming bright multilayer coating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming a bright multilayer coating film having a unique design that allows its hue to change continuously from near yellow green to near blue green within the same color range of green, according to a viewing angle, and shines in golden color in a highlight part and appears blue as well in a shade part. <P>SOLUTION: The method of forming a bright multilayer coating film includes forming an undercoat layer on a substrate, forming a bright basecoat layer thereover, and subsequently forming a clearcoat layer thereover. The bright multilayer coating film has a green hue of from 10Y to 10B in a Munsell hue circle (20 hues), lightness (V) of 1 to 5, and chroma (C) of 1 to 6, in the Munsell color system. The paint composition that forms the bright basecoat layer includes a coloring pigment (b) and a silica flake pigment (a) of a mean diameter of 5 to 40 &mu;m coated with titanium dioxide, in which composition, the concentration of the pigment (a) is 0.1 to 20 mass% and the concentration of the pigment (b) is 0.1 to 20 mass%, with the pigment (a) displaying yellow, green, and blue continuously. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a method for forming a glittering multilayer coating film having a unique and excellent design that can be applied to painting of an automobile body or the like.

  A plurality of coating films having various roles are sequentially formed on the surface of a base material such as an automobile body to protect the base material and at the same time impart a beautiful appearance and an excellent design. As a method of forming a multilayer coating film, there is a method in which an undercoat film such as an electrodeposition coating film is formed on a substrate having excellent conductivity, and an intermediate coating film and a top coating film are sequentially formed thereon. It is common. In particular, the top coat film comprising a base coat film and a clear coat film greatly affects the appearance and design of the coat film. In particular, in automobiles, the appearance and design of a top coating film composed of a base coating film and a clear coating film are extremely important. Also, recently, consumers tend to prefer a paint color with a glittering radiance rather than a solid color. The glittering radiance has the effect of emphasizing a design having a complicated shape such as an automobile. In particular, it has the effect of strongly emphasizing the press line of a fender portion and a door portion that can be seen well from the outside and shine well. Such an effect is due to the glittering pigment contained in the glittering coating film, and the reflection angle of light changes in a complicated shape part of an automobile, so that it has a glittering glitter feeling. The role of the glitter coating is very important. In addition, consumer preference has recently increased, and in addition to the glittering shine, further designs such as a color change depending on the viewing angle are required for the coating film.

  For example, Japanese Patent Laid-Open No. 2000-86943 (Patent Document 1) discloses a dichroic coating composition exhibiting dichroism characterized by blending a metal oxide-coated silica flake pigment as a bright pigment. Disclose.

  Japanese Patent Application Laid-Open No. 2002-192067 (Patent Document 2) discloses a glittering multilayer coating film comprising a color base coating layer, a glittering coating layer containing a metal oxide-coated silica flake pigment, and a top clear coating layer. Disclosed is a forming method. This glittering multi-layer coating film has a dichroic luster that exhibits different colors when viewed from the front (highlighted portion) of the coated object and when viewed obliquely (shaded portion).

  Furthermore, Japanese Patent Application Laid-Open No. 2001-31911 (Patent Document 3) discloses a polychromatic coating composition containing a metal oxide-coated silica flake pigment. The metal oxide-coated silica flake pigment contained in this paint can achieve multicolor properties that exhibit a plurality of colors depending on the viewing angle, and at the same time, achieves improved thermal stability of the coating film.

  However, although these pleochroic coating films change in color according to the viewing angle, the hue does not change gradually and continuously in similar colors.

  In recent years, there has been a tendency to prefer more colorful glitter coatings, especially in countries such as Europe and the United States, which are popular in gold, yellow, green, blue, etc. Is expensive.

JP 2000-86943 A JP 2002-192067 A JP 2001-31911 A

  The present invention aims to provide a method for forming a glittering multilayer coating film having an unprecedented unique design having a green hue, and in particular, from green close to yellow to green close to blue depending on the viewing angle. The hue changes continuously within the same color of green, and when viewed from the front of the painted object, that is, it shines like gold in the highlight area, and when viewed from the diagonal of the painted object, that is, blue in the shade area. It aims at providing the formation method of the glittering multilayer coating film which has the unique design which does not exist conventionally and looks like this. Another object of the present invention is to enhance a glittering radiance not only in a highlight portion but also in a shade portion.

  As a result of intensive studies, the present inventors have blended the paint with a specific blending amount of a titanium dioxide-coated silica flake pigment (a) having a specific particle size and a color pigment (b), thereby obtaining a hue. Changes continuously from a green color close to yellow to a green color close to blue within a wide range of similar green colors, and in some cases, the highlights of the paint shine like gold and shade Then, it discovered that the glittering multilayer coating film which has the unique design of the wide green which does not appear in the past which looks like blue was obtained, and came to complete this invention. Therefore, this invention provides the formation method of the following glittering multilayer coating films.

A method for forming a glittering multilayer coating film, wherein a glittering base coating film layer is formed on a substrate on which a base coating film layer is formed, and further a clear coating film layer is formed thereon,
In the Munsell color system, the glittering multi-layer coating film has a 10Y to 10B green hue of the Munsell hue ring (20 hues), and a lightness (V) of 1 to 5 and a saturation of 1 to 6 (C )
The glittering base coating composition for forming the glittering base coating layer contains a titanium dioxide-coated silica flake pigment (a) having an average particle size of 5 to 40 μm and a coloring pigment (b),
The concentration (PWC) of the pigment (a) is 0.1 to 20% by mass,
The concentration (PWC) of the pigment (b) is 0.1 to 20% by mass,
The pigment (a) plays yellow, green and blue continuously,
A method for forming a glittering multilayer coating film.

  In the method for forming a glittering multilayer coating film of the present invention, the mass ratio ((a) / (b)) of the pigments (a) and (b) is preferably 9/1 to 1/9.

  In the method for forming a glittering multilayer coating film according to the present invention, the glittering multilayer coating film preferably has a green hue of 5G to 10BG in a Munsell hue ring (20 hues).

  In the method for forming a glittering multilayer coating film of the present invention, the glittering multilayer coating film preferably has a wide interference width.

  The present invention also relates to a glittering multilayer coating film comprising a glittering base coating layer and a clear coating layer, which is formed by the above-described method for forming a glittering multilayer coating film.

  According to the present invention, the hue gradually changes from a green color close to yellow to a green color close to blue within a wide range of similar green colors, and when viewed from the front, it looks like a gold color. It is possible to provide a glittering multilayer coating film that has a unique green design that is visible and appears blue when viewed from an oblique direction. Such a unique and unique green-based hue that the glittering multilayer coating film formed by the present invention has is represented by the Munsell color system (20 hues) in the Munsell color system shown in FIG. It changes continuously and widely from (green close to yellow) to 10B (green close to blue), and the hue located between 10Y and 10B is 5GY, 10GY, 5G, 10G, 5BG, 10BG and 5B. Each of the hues can be clearly observed visually. Previously there were two-color and multi-colored glitter coatings, but these did not change the hue gently within the same color, but changed the hue dynamically to a completely different hue. there were. Therefore, the hue which changes slowly and continuously in the green color obtained by the present invention is a design that has never been seen before and is very surprising.

  Furthermore, surprisingly, the glittering multilayer coating film formed according to the present invention has a Munsell hue ring (20 hues) from 10Y (green near yellow) to 10B (close to blue) depending on the viewing angle, as described above. As shown in FIG. 2, when the highlight part (2) where the incident light (5) of the coated object (1) hits is viewed from the front, as shown in FIG. Due to the synergistic effect with other glitter pigments and clear coating layers that may be included, it also appears gold. Therefore, when the glittering multi-layer coating film formed in the present invention is applied to a complicated object such as an automobile body, an effect of conspicuous the design itself of the object such as a fender or a press line can be obtained. . In addition, the shade part (3) of the painted object (1) shown in FIG. 2 may appear blue due to the light intensity and contrast with the highlight part (2). Further emphasis can be made.

  In addition, as shown in FIG. 2, the glittering multilayer coating film formed by the present invention is not only the highlight portion (2) of the article to be coated (1), but surprisingly, the pseudo portion (3). Also in the intermediate part (4), it is possible to express a glittering glitter and provide an excellent design to the coating film.

The Munsell color wheel (20 hues) of the Munsell color system is shown. The highlight part (2), shade part (3), intermediate part (4) and incident light (5) of the coated product (1) are shown. The measuring method of the hue change according to an angle is shown. The a * value and b * value of the glittering multilayer coating film formed in Example 1 and their detection limits are shown. The a * value and b * value of the glittering multilayer coating film formed in Comparative Example 1 and the detection limit thereof are shown.

  The present invention relates to a method for forming a glittering multi-layer coating film, wherein the hue continuously changes from a green color close to yellow to a green color close to blue within a similar green color, and when viewed from the front, is golden. It is possible to provide a glittering multilayer coating film having an unprecedented green-based unique design.

  In this invention, the color of a coating film is shown by the Munsell color system. The Munsell color system is well known to those skilled in the art as “color display method by three attributes” (JIS Z 8721), and the three attributes of color are hue (H) and lightness (V). The colors are classified according to the saturation (C).

  In the Munsell color system, the hue (H) can be represented by a combination of a Munsell hue ring symbol (R, Y, G, B and P) and a number (such as 5 and 10) shown in FIG. In the Munsell color wheel, “R” indicates red, “Y” indicates yellow, “G” indicates green, “B” indicates blue, and “P” indicates purple. The intermediate hues “YR” indicate yellow red, “GY” indicates green yellow, “BG” indicates blue green, “PB” indicates purple blue, and “RP” indicates Shows red purple. In the Munsell color system, “10 hues” in the Munsell hue circle is a general term for hues assigned the number “10” as shown in FIG. Also, the “20 hue” of the Munsell hue ring, as shown in FIG. 1, is obtained by adding the number “5” to the hue located in the middle of the “10 hue” of the Munsell hue ring to make “20 hue”. is there. In addition, in the Munsell color system, the hue located in the middle of the “20 hue” of the Munsell hue ring may be given the number “2.5” or “7.5” to be “40 hue”. Note that in the Munsell hue circle, as shown in FIG. 1, the hue indicated by “2.5Y” is so-called “yellow” and the hue indicated by “2.5PB” is so-called “blue”. There is a need.

  In the Munsell color system, lightness (V) is indicated by a value of 0 to 10, and is an index indicating the brightness of the color. The smaller the value, the darker the color, and the higher the value, the brighter the value. . The brightness (V) of the glittering multilayer coating film formed by the present invention is 1 to 5, preferably 2 to 4.

  In the Munsell color system, the saturation (C) is indicated by a value of 0 to 14, and is an index indicating the vividness of the color. The smaller the value, the clearer the color, and the larger the value, the more the color Indicates vivid. The chroma (C) of the glittering multilayer coating film formed according to the present invention is 1 to 6, preferably 2 to 4.

  In the present invention, the color of the coating film, that is, the hue (H), brightness (V), and saturation (C) of the Munsell color system, for example, “SM Color Computer SM-T” manufactured by Suga Test Instruments Co., Ltd. Can be measured. Alternatively, it is determined by visually comparing a color sample of a color chart collection whose scale was shown in the color measurement committee of the Optical Society of America in 1943 and the obtained coated plate by visual evaluation. Can do.

  The hue (H) of the glittering multi-layer coating film formed by the present invention is from 10Y (green near yellow) to 10B (green near blue) according to the Munsell hue ring (20 hues) of the Munsell color system. It changes slowly and continuously within a broad green hue system.

  For example, an object having a complicated shape such as an automobile body often has a painted surface that is curved or bent in some cases. Generally, even a roof portion is hardly flat at all. In particular, the front part including the engine hood, the fender part, the door part, and the rear part, which determine the design of the automobile body, have a particularly complicated shape. In recent years, press lines are often intertwined with each other to form an overall design. As schematically shown in FIG. 2, the portion where the light (5) hits the painted object (1) well is the highlight portion (2), the portion where the light does not hit well is the shade portion (3), and the highlight portion (2). When the intermediate portion (4) is defined between the shade portion (3) and the shade portion (3), the bright multilayer coating film formed by the present invention has a 10Y Munsell hue ring (20 hues) in the highlight portion (2). The hue (green near yellow) is shown, and the shade portion (3) shows the 10B hue (green near blue) of the Munsell hue ring (20 hues). In the intermediate part (4), the hue from 10Y to 5GY, 10GY, 5G, 10G, 5BG, 10BG and 5B in order from the highlight part (2) to the shade part (3) is directed to 10B. Changes slowly and continuously. Therefore, in the present invention, the hue changes gently and continuously within the greenish color, and the intermediate colors can be clearly observed visually. In this field, Majora (MAZIORA (registered trademark), manufactured by Nippon Paint Co., Ltd.) is well known as a representative paint that brings about a hue change, and these paints are purple (P), green (G), and blue. As in (B) and yellow (Y), the hue changes dynamically and instantaneously to a hue located on the opposite side of the Munsell hue ring, and the hue changes slowly and gently within the same color is not. Therefore, the glittering multilayer coating film formed by the method of the present invention can provide a design that is completely different from conventional polychromatic paints.

  As described above, the present invention continuously plays a green hue from 10Y (green near yellow) to 10B (green near blue) of the Munsell hue ring (20 hues) and has a wide interference width. Although no unique design can be provided to the coating film, these characteristics are that the glitter base coating composition that forms the glitter base coating layer contained in the glitter multilayer coating film has a specific particle size. This can be achieved by including a titanium dioxide-coated silica flake pigment (a) having a colorant and a coloring pigment (b), and blending them in a specific ratio. Hereafter, the formation method of the glittering multilayer coating film of this invention and the coating composition which forms each coating film layer are demonstrated in detail.

  In the present invention, a glittering base coating composition is applied on a substrate to form a glittering base coating layer, and further a clear coating composition is applied thereon to form a clear coating layer. As the top coating film, a glittering multilayer coating film including a glittering base coating film layer and a clear coating film layer can be formed. In the Munsell color system, the glittering multilayer coating film obtained by the method of the present invention has a 10Y to 10B green hue of the Munsell hue ring (20 hues) shown in FIG. 1, preferably a 5G to 10BG green hue. As well as a lightness (V) of 1 to 5 and a saturation (C) of 1 to 6, and the hue changes continuously in a greenish similar color according to the angle, and the highlight portion Not only in the shade part, but also in a unique design that has a glittering radiance.

Glossy Base Coating Composition In the present invention, a glittering base coating composition that can form a glittering base coating layer (sometimes referred to simply as “brilliant coating layer” in the present specification) ( In the present specification, it may be simply referred to as “brilliant coating composition”) is a vehicle and a specific titanium dioxide-coated silica flake pigment (a) as a bright pigment (hereinafter referred to as “pigment”). (In some cases, abbreviated as “(a)”) and colored pigments (b) [hereinafter also abbreviated as “pigment (b)”].

  In the present invention, by forming a glittering base coating layer from a glittering base coating composition containing pigment (a) and pigment (b) in a specific ratio, and further forming a clear coating layer thereon It is possible to form a glittering multilayer coating film in which the hue changes continuously within the same color according to the angle.

  The coated article (1) shown in FIG. 2 is obtained by forming a glittering multilayer coating film according to the present invention on a curved base material (convex toward the front side of the paper surface) like an automobile door. In the highlight part (2), this glittering multilayer coating film exhibits a green color close to yellow represented by “10Y” in the Munsell hue ring (20 hues) in FIG. Due to the visual effect of other glittering pigments and clear coating layers that can be included in the film, it also appears golden. Further, the shade part (3) exhibits a green color close to blue represented by “10B” in the Munsell hue ring (20 hues) shown in FIG. 1, depending on the light intensity and contrast with the highlight part (2). Sometimes it looks blue. Here, the highlight part of the coating surface means a position where the incident light (5) and the light whose incident angle and reflection angle are almost equal to each other hit the incident light (5). This means a position where the incident angle and the reflection angle are different from each other and the light does not strike well (so-called shadow). In the intermediate portion (4) between the highlight portion (2) and the shade portion (3), the hue from the highlight portion (2) to the shade portion (3) is the Munsell hue ring (20 hues) shown in FIG. From “10Y” (green near yellow) to “10B” (green near blue). Accordingly, in the middle portion (4), the green color of “5GY”, “10GY”, “5G”, “10G”, “5BG”, “10BG” and “5B” of the Munsell hue ring (20 hues) in FIG. Each hue can be clearly confirmed visually. As a result, in the coated object (1), the highlight part (2), the intermediate part (4), and the shade part (3) are changed to at least three colors in the same color of the green color depending on the viewing angle. The hue can be clearly confirmed visually. Since the coated object (1) is curved, the boundaries of the highlight part (2), the intermediate part (4) and the shade part (3) are clearly distinguished in the actual coating film. Instead, a unique design is provided in which the hue gradually changes within the green-related colors over the highlight portion (2), the intermediate portion (4), and the shade portion (3).

  As a first condition for expressing the design of at least three colors, it is mentioned that the hue of the pigment (a) continuously plays at least yellow, green and blue. In the present invention, the hue obtained by mixing all of the pigment (a) and the pigment (b) is preferably in the green system. In the present invention, the present invention relates to a glittering multilayer coating film in which the hue changes within a greenish similar color, but the hue can be changed within the same color even in other hues such as blue, red and yellow. Is possible. In that case, a bright pigment having at least five continuous hues in the Munsell hue ring (20 hues) is selected, and the pigment (a) so that the hue obtained by mixing the pigments (a) and (b) is just in the middle. By selecting a) and (b), a hue change within a similar color can be achieved.

  Further, as the second condition, the pigment (a) and the pigment (b) concentration (Pigment Weight Concentration (PWC)) is 0.1 to 20% by mass in the glittering base coating composition, respectively. It is done.

Pigment
Pigment (a): Titanium dioxide-coated silica flake pigment In the present invention, the pigment (a) blended in the glittering base coating composition as a glittering pigment capable of imparting a glittering glitter to the coating film is coated with titanium dioxide. Silica flake pigment.

The pigment (a) that can be used in the present invention is a metal oxide layer containing titanium dioxide (TiO ₂ ) in natural or synthetic silica flakes (silicon dioxide: SiO ₂ ) [hereinafter referred to as titanium dioxide layer] May be desirably coated by uniform coating.

  The thickness of the silica flake base material is 300 to 1000 nm, preferably 300 to 700 nm. When the thickness of the silica flake base material deviates from the above range, the color developability defined in the present invention may be lowered.

  The titanium dioxide layer contains 15 to 20% by mass of titanium dioxide based on the mass of the coating layer of the silica flake pigment, and as other metal oxides, 2.0 to 4.0% by mass of tin dioxide and 1 It may contain 0.0 to 3.0% by mass of zirconium dioxide. When the titanium dioxide layer contains these components within the above range, the color developability defined in the present invention can be achieved.

  The thickness of the titanium dioxide layer is 50 to 300 nm. If the thickness of the titanium dioxide layer deviates from the above range, the color developability defined in the present invention may not be achieved.

The average particle diameter (D ₅₀ ) of the pigment (a) is 5 to 40 μm, preferably 10 to 35 μm. If the average particle size deviates from the above range, the color developability defined in the present invention may not be exhibited.

The average particle size of the pigment (a) is a median value (D ₅₀ ) measured by a particle size distribution by a laser diffraction method.

  Since the pigment (a) is an angle-dependent pigment, it has the above-described structure, so that the color travel property, that is, the combination of the incident angle of light and the reflection angle (that is, the observation angle or the receiving angle) is at least yellow, green In addition, it plays blue and blue continuously, and can exhibit a gold color or a silver color depending on the viewing angle.

  In addition, since the pigment (a) is based on silica flakes, the pigment (a) has very high transparency, and even when used in combination with other colored pigments, it does not adversely affect the hue. is there.

  The pigment (a) may be a commercially available product, and examples thereof include MERCK color stream T20-04 WNT Lapis Sunlite (colorstream (registered trademark) T20-04 WNT Lapis Sunlight). Among them, MERCK color stream T20-04 WNT Lapis Sunlight having yellow, gold, silver, green, and blue color travel properties is particularly preferable.

  In the present invention, two or more pigments (a) may be used in combination.

  The concentration (PWC) of the pigment (a) is 0.1 to 20% by mass, preferably 0.1 to 10% by mass in the glittering base coating composition. If the amount exceeds 20% by mass, the finished appearance may be deteriorated.

  In the present invention, the concentration (PWC) of the pigment (a) represents the mass of the pigment (a) as a percentage (mass%) with respect to the mass of the total solid content of the glittering base coating composition. The total solid content of the glittering base coating composition includes pigment (a) and pigment (b), a resin component (solid content) that serves as a vehicle for the glittering base coating composition, and any other component (solid content). ) Are all included.

Pigment (b): The color pigment pigment (b) is not particularly limited as long as it is an organic and / or inorganic color pigment capable of producing a green hue in combination with the pigment (a). In addition, as the pigment (b), two or more pigments may be used in appropriate combination.

Examples of organic coloring pigments include azo pigments (for example, azo chelate pigments, insoluble azo pigments, condensed azo pigments), phthalocyanine pigments, quinacridone pigments, benzimidazolone pigments, diketopyrrolopyrrole pigments. pigments, isoindolinone pigments, threne pigments, perinone pigments, perylene pigments, indigo pigments, dioxane pigments, quinophthalone pigments, dioxazine pigments, and metal complex organic pigments, and the like, in combination of two or more May be used.

  Examples of inorganic coloring pigments include carbon black, titanium oxide, yellow lead, zinc white, cadmium red, molybdenum red, chromium yellow, chromium oxide, Prussian blue, cobalt blue, yellow iron oxide, and bengara. A combination of the above may also be used.

  When a change in hue within the same color is expected, the pigment (b) has a green hue just in the middle of the hue (in the hue on the Munsell hue ring (20 hue)) played by the pigment (a). Is desirable. Alternatively, it is desirable that the hue obtained by mixing all of the pigment (a) and the pigment (b) is in the green system. For example, when the hue change depending on the viewing angle in the green system is expected, the hue obtained by mixing all of the pigment (a) and the pigment (b) is from 10Y to 10B of the Munsell hue ring (20 hues). It is desirable to be selected from the group consisting of 5G to 5BG.

  The concentration (PWC) of the pigment (b) is 0.1 to 20% by mass, preferably 0.1 to 5% by mass. If the amount is less than 0.1% by mass, there is a risk of a problem such as a decrease in green color development, and if it exceeds 20% by mass, there is a risk that the color developability of the pigment (a) may decrease.

  In the present invention, the concentration (PWC) of the pigment (b) represents the mass of the pigment (b) in percentage (mass%) with respect to the mass of the total solid content of the glittering base coating composition. The total solid content of the glittering base coating composition includes pigment (a) and pigment (b), a resin component (solid content) that serves as a vehicle for the glittering base coating composition, and any other component (solid content). ) Is included.

  In the present invention, the mass ratio ((a) / (b)) of the pigment (a) and the pigment (b) is 9/1 to 1/9, preferably 8/2 to 5/5. If the mass ratio ((a) / (b)) exceeds 9/1, there is a risk of problems such as a decrease in green color development. If it is less than 1/9, the color developability of the pigment (a) is low. There is a risk of problems such as deterioration.

  In the present invention, not only pigments (a) and (b), but also other pigments other than pigment (a), such as extender pigments and extender pigments, are appropriately blended into the glitter base coating composition as necessary. May be.

  Examples of other bright pigments other than pigment (a) include metal aluminum flakes, metal titanium flakes, stainless steel flakes, and glass flakes, and two or more may be used in combination.

  Examples of extender pigments include calcium carbonate, barium sulfate, clay, talc and the like, and two or more may be used in combination.

  In the glittering base coating composition, the total pigment concentration (PWC) is 0.1 to 50% by mass, preferably 0.1 to 30% by mass. There is a fear that it cannot be achieved.

Vehicle The vehicle contained in the glittering base coating composition that can be used in the present invention is a dispersion of the above-mentioned pigment, and includes a film-forming resin and, if necessary, a crosslinking agent (and / or Curing agent).

  Examples of the film-forming resin constituting the vehicle include (A) acrylic resin, (B) polyester resin, (C) alkyd resin, (D) fluororesin, (E) epoxy resin, (F) polyurethane resin, (G) Polyether resin etc. are mentioned, Especially an acrylic resin and a polyester resin are used preferably. These can be used in combination of two or more. In addition, the film-forming resin includes a curable type and a lacquer type, but a curable type is usually used. In the case of a curable type, it is used by mixing with a crosslinking agent such as an amino resin, a (block) polyisocyanate compound, an amine, a polyamide, or a polyvalent carboxylic acid, and is subjected to a curing reaction at heating or normal temperature. Can be advanced. It is also possible to use a film-forming resin of a type having no curability in combination with a type having curability.

(A) Acrylic resin Examples of the acrylic resin include a copolymer of an acrylic monomer, or a copolymer of an acrylic monomer and another ethylenically unsaturated monomer. Acrylic monomers that can be used for the copolymerization include methyl, ethyl, propyl, n-butyl, i-butyl, t-butyl, 2-ethylhexyl, lauryl, phenyl of acrylic acid, methacrylic acid, acrylic acid or methacrylic acid. , Benzyl, 2-hydroxyethyl, 2-hydroxypropyl and the like, ring-opening adducts of caprolactone of acrylic acid or 2-hydroxyethyl methacrylate, acrylamide, methacrylamide and N-methylolacrylamide. Other ethylenically unsaturated monomers copolymerizable with these include styrene, α-methylstyrene (or dimer), itaconic acid, maleic acid, vinyl acetate and the like. Moreover, it is preferable to make an acrylic resin into an aqueous emulsion by a method known to those skilled in the art, for example, a method disclosed in JP-A-2007-39615.

(B) Polyester resin Examples of the polyester resin include saturated polyester resins and unsaturated polyester resins, and examples include condensates obtained by heat condensation of polybasic acids and polyhydric alcohols. Examples of the polybasic acid include saturated polybasic acids and unsaturated polybasic acids. Examples of the saturated polybasic acid include phthalic anhydride, terephthalic acid, succinic acid, and the like. Examples of the acid include maleic acid, maleic anhydride, fumaric acid and the like. Examples of the polyhydric alcohol include dihydric alcohol and trihydric alcohol. Examples of the dihydric alcohol include ethylene glycol and diethylene glycol. Examples of the trihydric alcohol include glycerin and trimethylolpropane. Etc.

(C) Alkyd resins Alkyd resins include the above polybasic acids and polyhydric alcohols, modified oils and fats and fatty acids (soybean oil, linseed oil, coconut oil, stearic acid, etc.), natural resins (rosin, succinic acid, etc.), etc. An alkyd resin obtained by reacting and modifying the agent can be used.

(D) Fluororesin As the fluororesin, any one of vinylidene fluoride resin, tetrafluoroethylene resin or a mixture thereof, a polymerizable compound containing a fluoroolefin and a hydroxy group, and other copolymerizable vinyl compounds are used. Examples thereof include resins made of various fluorine-based copolymers obtained by copolymerizing the following monomers.

(E) Epoxy resin Examples of the epoxy resin include a resin obtained by a reaction of bisphenol and epichlorohydrin. Examples of bisphenol include bisphenol A and F. Examples of the bisphenol type epoxy resin include Epicoat 828, Epicoat 1001, Epicoat 1004, Epicoat 1007, Epicoat 1009 (all manufactured by Shell Chemical Co., Ltd.) and the like, and these can be chained using an appropriate chain extender. Extended ones can also be used.

(F) Polyurethane resin Examples of the polyurethane resin include resins having a urethane bond obtained from various polyol components such as acrylic, polyester, polyether, and polycarbonate and a polyisocyanate compound. Examples of the polyisocyanate compound include 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), and mixtures thereof (TDI), diphenylmethane-4,4 ′. Diisocyanate (4,4′-MDI), diphenylmethane-2,4′-diisocyanate (2,4′-MDI), and mixtures thereof (MDI), naphthalene-1,5-diisocyanate (NDI), 3,3 ′ -Dimethyl-4,4'-biphenylene diisocyanate (TODI), xylylene diisocyanate (XDI), dicyclohexylmethane diisocyanate (hydrogenated HDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), hydrogenated xylylene diene Isocyanate (HXDI) etc. It can be mentioned.

(G) Polyether resin The polyether resin is a polymer or copolymer having an ether bond, and is a polyoxyethylene polyether, polyoxypropylene polyether, polyoxybutylene polyether, bisphenol A or bisphenol. A polyether resin having at least two hydroxyl groups per molecule such as a polyether derived from an aromatic polyhydroxy compound such as F, or the polyether resin and succinic acid, adipic acid, sebacic acid, phthalic acid, Mention may be made of carboxyl group-containing polyether resins obtained by reacting polycarboxylic acids such as isophthalic acid, terephthalic acid and trimellitic acid, or reactive derivatives such as acid anhydrides thereof.

  When the vehicle contains a cross-linking agent, the ratio of the film-forming resin and the cross-linking agent is preferably 90 to 50% by mass of the film-forming resin and 10 to 50% by mass of the cross-linking agent in terms of solid content. The film-forming resin is 85 to 60% by mass, and the crosslinking agent is 15 to 40% by mass. When the crosslinking agent is less than 10% by mass (when the coating film-forming resin exceeds 90% by mass), the crosslinking in the coating film may not be sufficient. On the other hand, when the cross-linking agent exceeds 50% by mass (when the coating film-forming resin is less than 50% by mass), the storage stability of the coating composition is lowered and the curing rate is increased, so that the coating film appearance is deteriorated. There is.

Other components The glittering base coating composition that can be used in the present invention is a colloidal dispersion mainly composed of a polyamide wax or a polyethylene oxide which is a lubricating dispersion of an aliphatic amide, in addition to the above components. Anti-settling agents such as polyethylene wax, curing catalysts, UV absorbers, antioxidants, leveling agents, surface conditioners such as silicon and organic polymers, anti-sagging agents, thickeners, antifoaming agents, lubricants, crosslinkable heavy A coalesced particle (microgel) etc. can be added suitably. These additives can improve the performance of paints and coating films by blending them at a ratio of 15 parts by mass or less with respect to 100 parts by mass of the vehicle (based on solid content).

  The glittering base coating composition of the present invention is provided in a form in which the above-mentioned constituents are usually dissolved or dispersed in a solvent. Any solvent can be used as long as it dissolves or disperses the vehicle, and an organic solvent and / or water can be used. Examples of the organic solvent include those usually used in the paint field. Examples thereof include hydrocarbons such as toluene and xylene, ketones such as acetone and methyl ether ketone, esters such as ethyl acetate, cellosolve acetate and butyl cellosolve, alcohols and the like. From the viewpoint of the environment, it is preferable to use water when the use of the organic solvent is regulated. In this case, an appropriate amount of a hydrophilic organic solvent may be blended.

  In a particularly preferred embodiment, the glittering base coating composition that can be used in the present invention comprises the above-described pigment (a) and pigment (b), and a film-forming resin containing an acrylic resin emulsion as a vehicle. A curing agent containing an aqueous dispersion of a hydrophobic melamine resin having a particle size of 20 to 140 nm obtained by water-dispersing a reaction product obtained by reacting a resin and a hydrophobic melamine resin, and a crosslinking agent. As a result, a coating film having excellent color developability can be obtained. Further, in the method for forming a multilayer coating film in automobile coating, when the above glittering base coating composition is used as a water-based coating, it is possible to obtain a coating film having excellent recoat adhesion, chipping property, and water adhesion resistance. . Therefore, the above glittering base coating composition can be suitably used as an aqueous glittering base coating composition.

Coating method The method for forming the glittering multi-layer coating film of the present invention is to form the glittering base coating layer by applying the above glittering base coating composition on a substrate, and further, A clear coating composition is applied to form a clear coating layer, and a glittering multilayer coating including a glittering base coating layer and a clear coating layer is formed on a substrate. In the present invention, the above-described glittering base coating composition can be suitably used as an aqueous glittering paint for automobiles (automobile bodies, parts, etc.).

  The substrate is not particularly limited, and metals such as iron, aluminum, magnesium, copper, tin, zinc or alloys thereof and molded articles thereof; inorganic materials such as glass, cement and concrete; polyethylene resins, Polypropylene resin, ethylene-vinyl acetate copolymer resin, polyamide resin, acrylic resin, vinylidene chloride resin, polycarbonate resin, polyurethane resin, epoxy resin, polyester resin, polystyrene resin, ABS resin, and various plastics such as FRP Examples include materials and molded articles or foams thereof; natural or synthetic materials such as wood and fiber materials (paper, cloth, etc.). Since the base material effectively expresses the design of at least three colors obtained by the present invention, for example, car bodies and parts (car bodies, doors, etc.) such as passenger cars, trucks, motorcycles, buses, etc. It is preferable that it has a curved surface. Specific examples of the plastic molded product include automobile parts such as a spoiler, a bumper, a mirror cover, a grill, and a door knob. Furthermore, these plastic molded articles are preferably washed with ion-exchanged water or a neutral detergent. Furthermore, primer coating for enabling electrostatic coating may be applied.

  In the method for forming the glittering multi-layer coating film of the present invention, when the substrate is an automobile body or its parts, the conductive substrate is previously degreased or chemically treated (phosphate, chromate, etc.). After the chemical conversion treatment), it is preferable to apply base coating such as electrodeposition coating or intermediate coating to the base material.

  Electrodeposition coating is performed for the purpose of imparting rust prevention by forming an electrodeposition coating film on a conductive substrate such as a steel sheet. The electrodeposition coating composition that can be used is not particularly limited, and any of a cationic electrodeposition coating composition and an anionic electrodeposition coating composition that are well known to those skilled in the art can be used. From the viewpoint, a cationic electrodeposition coating composition is preferable, and an epoxy cationic electrodeposition coating composition is particularly preferable.

  In the present invention, when the base material is an automobile body or a steel plate, pretreatment up to degreasing, water washing, chemical film formation, water washing, pure water washing, and drying can be performed by a conventionally known method before electrodeposition coating film formation. preferable. As an electrodeposition coating film forming method, an appropriate method may be arbitrarily selected from conventionally known methods. The electrodeposition coating film forming conditions, the bake curing conditions, the thickness of the electrodeposition coating film, etc. What is necessary is just to determine suitably according to the kind of material, the electrodeposition coating composition to be used, etc.

  In the intermediate coating, an intermediate coating layer is formed on the substrate or electrodeposition coating to improve the performance such as concealment of the base, chipping resistance, and adhesion to the top coating layer. Is called. In addition, the intermediate coating layer also functions as a base for smoothing the final glittering multilayer coating film to form a coating film with good appearance, and further, an electrodeposition coating layer and a top coating layer. And weather resistance against deterioration of the coating film due to ultraviolet rays and water reaching through the surface of the coating film. There are no particular limitations on the intermediate coating composition that can form the intermediate coating layer, and other than solvent-based coatings well known to those skilled in the art, water-based coatings, powder coatings, high solid coatings, etc. Specifically, epoxy ester / melamine resin, alkyd / melamine resin or oil-free polyester / melamine resin paint, acrylic resin and / or polyester resin and amino resin and / or isocyanate curing agent are combined. In addition, it can be appropriately selected from conventionally known intermediate coating materials such as intermediate coating materials.

  Regarding the method of forming the intermediate coating layer, an appropriate method may be arbitrarily selected from conventionally known methods. Further, in the present invention, a gray-based intermediate coating composition comprising carbon black and titanium dioxide as main pigments, a combination of set gray and various colored pigments that match the lightness and hue of the top coat layer, so-called A color intermediate coating composition can be used. These color intermediate coating compositions can develop a composite color of the intermediate coating layer and the top coating layer, and can further enhance the design. Further, flat pigments such as aluminum powder and mica powder may be added to these intermediate coating compositions. Further, the intermediate coating composition may contain additives that can be usually added to the coating, for example, a surface conditioner, an antioxidant, an antifoaming agent, and the like. The dry film thickness of the intermediate coating layer is preferably 20 to 100 μm, more preferably 30 to 50 μm.

  In the method for forming a glittering multi-layer coating film of the present invention, preferably, a glittering base coating composition is applied on a substrate to form a glittering base coating layer, A clear coating composition is applied to form a clear coating layer.

  When the base material is a base material having a base coating layer subjected to base coating such as electrodeposition coating or intermediate coating, wet-on-wet (W / W) method or wet-on-dry (W / D) method, the glittering base coating composition can be applied to form a glittering base coating layer. Next, a clear coating composition is applied on the glittering base coating layer by a wet-on-wet (W / W) method or a wet-on-dry (W / D) method to form a clear coating layer. be able to. The W / W method means that after coating the coating composition, the coated film is dried by air drying or the like, or semi-cured at a temperature of less than 100 ° C., if necessary, and uncured or semi-cured. On the other hand, the W / D method is a method in which a coating composition is applied, and then the coating composition is applied and then baked and cured. It is a method of applying a composition.

  The method for applying the glittering base coating composition is not particularly limited. For example, a spray method or a roll coater method is preferable. From the viewpoint of improving the appearance, multistage coating by air electrostatic spray coating, preferably 2 is preferable. A coating method is preferable, in which coating is performed on a stage or a combination of air electrostatic spray coating and a rotary atomizing electrostatic coating machine called a metallic bell. It is also possible to paint multiple times.

  Although the film thickness of the coating film at the time of painting with the glittering base coating composition varies depending on the desired application, in general, the dry film thickness is preferably 5 to 30 μm, preferably 5 to 20 μm per coat. . If the dry film thickness is less than 5 μm, the underlying layer cannot be concealed, resulting in film breakage, and if it exceeds 30 μm, the sharpness may be deteriorated or defects such as unevenness or sagging may occur during painting. There is a fear. In order to obtain a multilayer coating film having a good appearance, it is preferable to heat the formed glittering base coating film at 40 to 100 ° C. for 2 to 10 minutes before applying the clear coating composition. This preheating is preferable because the orientation of the glitter pigment is not disturbed even if the clear coating composition is applied thereon.

  In the present invention, at least one clear coating layer can be formed on the glittering base coating layer thus formed. The clear coating layer smoothes and protects irregularities, flickering, and the like caused by the glitter pigment contained in the glitter base coating layer, and further gives an aesthetic appearance.

  The clear coating composition that can be used in the method for forming the glittering multi-layer coating film of the present invention is not particularly limited, and those generally used for top coating can be used. For example, acrylic resin A mixture of at least one thermosetting resin selected from polyester resins, fluororesins, epoxy resins, polyurethane resins, polyether resins and modified resins thereof, and the above-mentioned crosslinking agent and / or curing agent. Can be used.

  If necessary, the clear coating composition is a colored pigment, extender pigment, modifier, ultraviolet absorber, leveling agent as long as it does not impair the transparency or does not interfere with the design of the base. It is possible to add additives such as a dispersant and an antifoaming agent. Moreover, when the clear paint containing the carboxyl group-containing polymer and the epoxy group-containing polymer described in JP-B-8-19315 forms the glittering base coating layer by the acid rain countermeasure and the W / W method. Furthermore, it is preferably used from the viewpoint of not disturbing the orientation of the glitter pigment and the color pigment. In addition, the clear coating composition can take various forms such as a solvent type, an aqueous type, and a powder type. As the solvent-based paint or water-based paint, a one-component paint may be used, or a two-component paint such as a two-component urethane resin paint may be used.

  Preferred examples of the solvent-based clear coating composition include a combination of an acrylic resin and / or a polyester resin, an amino resin and / or an isocyanate, or a carboxylic acid / epoxy curing system in terms of transparency or acid etching resistance. And acrylic resin and / or polyester resin.

  Examples of the water-based clear coating composition include a resin obtained by neutralizing a film-forming resin contained in the solvent-based clear coating composition described above as an example of the solvent-type clear coating composition with a base to make it water-based. Things can be mentioned. This neutralization can be carried out by adding tertiary amines such as dimethylethanolamine and triethylamine before or after polymerization.

  Furthermore, it is preferable that a viscosity control agent is added to the clear coating composition in order to ensure coating workability. As the viscosity control agent, those generally showing thixotropy can be used. As such a thing, a conventionally well-known thing can be used, for example. Moreover, a curing catalyst, a surface conditioner, etc. can be included if necessary.

  In addition, as a clear coating composition used in the above-mentioned multilayer coating film forming method, Ford Cup No. 20 at 20 ° C. is used from the viewpoint of influence on the environment due to the content of the organic solvent. 4 is a solvent-type clear coating composition or a water-based clear coating composition, or a powder-type clear, in which the solid content of the clear coating composition when diluted to a viscosity of 20 to 50 seconds is 50% by mass or more A coating composition is preferred.

  In the present invention, the clear coating composition may be applied to the cured glittering base coating layer, but the W / W is applied to the uncured or semi-cured glittering base coating layer. It is preferable to apply the clear coating composition by the method. The method for applying the clear coating composition to the glittering base coating layer is not particularly limited. For example, a spray method or a roll coater method is preferable. A coating method using a rotary atomizing electrostatic coating machine called a bell or microbell can be given. It is also possible to paint multiple times. When the clear coating composition is applied a plurality of times, it may be baked and cured simultaneously after the final clear coating composition is applied, and it is not necessary to completely cure the previously formed clear coating film.

  On the other hand, as the powder-type clear coating composition, ordinary powder coatings such as thermoplastic and thermosetting powder coatings can be used. A thermosetting powder coating composition is preferred because a coating film having good physical properties can be obtained. Specific examples of the thermosetting powder coating composition include epoxy-based, acrylic-based, and polyester-based powder clear coating compositions, etc., and acrylic-based powder clear coating compositions having good weather resistance. Is particularly preferred.

  As described above, the clear coating layer formed on the glittering base coating layer (which may be uncured, semi-cured or fully cured) may be an electrodeposition coating or an intermediate coating. And a base coating layer (any of uncured, semi-cured, and fully cured) and the like, and are baked and cured at a predetermined temperature and a predetermined time to form a glittering multilayer coating film.

  The dry film thickness of the clear coating layer formed by applying the clear coating composition is generally preferably 10 to 80 μm, and more preferably 20 to 60 μm. When the dry film thickness is less than 10 μm, the unevenness of the foundation cannot be concealed, and when it exceeds 80 μm, there is a possibility that problems such as peeling or sagging may occur during coating.

  The clear coating film thus formed forms a cured coating film by simultaneously heating together with a preliminarily formed glitter base coating film. The heat curing temperature is preferably set to 80 to 180 ° C., more preferably 120 to 160 ° C., from the viewpoints of curability and physical properties of the obtained multilayer coating film. Although the heat curing time can be arbitrarily set according to the above temperature, it is appropriate that the heat curing temperature is 120 ° C. to 160 ° C. and the time is 10 to 30 minutes.

  The film thickness of the glittering multilayer coating film thus formed is generally 30 to 300 μm and preferably 50 to 250 μm. When the film thickness is less than 30 μm, the strength of the film itself decreases, and when it exceeds 300 μm, film physical properties such as a cooling / heating cycle may decrease. The multilayer coating film thus obtained is also one aspect of the present invention.

  The glittering multilayer coating film formed by the glittering multilayer coating film forming method of the present invention has extremely high glitter and color development, recoat adhesion, chipping resistance and water adhesion resistance on the surface thereof.

  In the present invention, preferably, the above-described glittering base coating composition, preferably an aqueous glittering base coating composition, is applied onto the substrate on which the above-mentioned base coating layer is formed, and an uncured glittering base coating composition is applied. A step (1) of forming a film layer, a step (2) of applying a clear coating composition on the uncured glittering base coating layer to form an uncured clear coating layer, and the above From the viewpoint of cost and workability, the method for forming a glittering multilayer coating film comprising the step (3) of simultaneously baking and curing the uncured glittering base coating film layer and the uncured clear coating film layer is particularly preferable. preferable.

  The glittering multilayer coating film formed on the substrate by the method of the present invention includes a glittering base coating film layer and at least one clear coating film layer. An undercoating layer selected from the group consisting of a coating layer and an intermediate coating layer may further be included. In the Munsell color system, the glitter (base) coating layer has a 10Y to 10B hue of the Munsell hue ring (20 hues), a lightness (V) of 1 to 5, and a saturation (C) of 1 to 6 Have

  The glittering multilayer coating film formed on the substrate by the method of the present invention is particularly characterized by the glittering base coating layer formed from the glittering base coating composition. In the Munsell color system, a wide range of green colors from 10Y to 10B in the Munsell hue ring (20 hues) shown in FIG. 1 and a lightness (V) of 1 to 5 And a saturation (C) of 1 to 6, and can cause at least three hue changes within the greenish color, depending on the viewing angle. Moreover, in the highlight part (2) shown in FIG. 2, it exhibits green (10Y) close to yellow, and further, due to the synergistic effect with other glitter pigments and clear paint film layers that can be included in the glitter paint film, It can be brilliant and shining like gold. Alternatively, the shade part (3) shown in FIG. 2 shows green (10B) close to blue, and appears to be blue depending on the light intensity and the contrast with the highlight part (2).

  These unconventional designs of the glittering multi-layer coating formed by the present invention make the shape stand out, especially when applied to a complex object such as an automobile body and exposed to sunlight. It is very effective. Moreover, since the glittering multilayer coating film formed by the present invention has a wide interference width, it can be brilliantly brilliantly even indoors where light is not strongly applied.

  The painting method of the present invention can be applied not only to automobile bodies, but also to all articles and products that require painting, such as the bodies of vehicles such as motorcycles and tricycles, parts thereof, containers, and electrical appliances.

  Hereinafter, the present invention will be described in more detail with reference to production examples, examples and comparative examples. In each example, “part” represents “part by weight”, and “%” represents “% by weight”.

Production Example 1: Preparation of glittering base coating composition (1)
Preparation of acrylic resin emulsion (Em-1) 135.4 parts of ion exchange water, 1.1 parts of Aqualon HS-10 (polyoxyethylene alkylpropenyl phenyl ether sulfate, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) The temperature was raised to 80 ° C. while mixing and stirring in a nitrogen stream. Next, 35.73 parts of methyl acrylate, 8.57 parts of butyl methacrylate, 5.7 parts of 2-hydroxyethyl methacrylate, 20 parts of styrene, 0.5 part of Aqualon HS-10, Adeka Soap NE-20 ( α- [1-[(allyloxy) methyl] -2-nonylphenoxy] ethyl) -ω-hydroxyoxyethylene (manufactured by Asahi Denka Co., Ltd., 80% aqueous solution) 0.5 part and ion-exchanged water 49.7 parts A first-stage ethylenically unsaturated monomer mixture and an initiator solution consisting of 0.21 part of ammonium persulfate and 8.6 parts of ion-exchanged water were dropped into the reaction vessel in parallel over 2 hours. After completion of the dropping, aging was performed at the same temperature for 1 hour.

  Furthermore, 25.3 parts of butyl methacrylate, 2.4 parts of 2-hydroxyethyl methacrylate, 2.3 parts of methacrylic acid, 0.1 part of Aqualon HS-10 and 24.7 parts of ion-exchanged water were added to this reaction vessel. A second stage ethylenically unsaturated monomer mixture and an initiator solution consisting of 0.08 parts ammonium persulfate and 7.4 parts ion-exchanged water were added dropwise in parallel over 0.5 hours at 80 ° C. . After completion of the dropping, aging was performed at the same temperature for 2 hours.

  Next, after cooling to 40 ° C. and filtering with a 400 mesh filter, 2.14 parts of ion-exchanged water and 0.24 part of dimethylaminoethanol were added to adjust the pH to 6.5, an average particle diameter of 80 nm, and a non-volatile content of 30%. An acrylic resin emulsion (Em-1) having a solid content acid value of 15 and a hydroxyl value of 35 was obtained.

Preparation of water-soluble acrylic resin 23.89 parts of dipropylene glycol methyl ether and 16.11 parts of propylene glycol methyl ether were added to a reaction vessel, and the mixture was heated to 105 ° C. with mixing and stirring in a nitrogen stream. Next, 13.1 parts of methyl methacrylate, 68.4 parts of ethyl acrylate, 11.6 parts of 2-hydroxyethyl methacrylate, 6.9 parts of methacrylic acid, 10.0 parts of dipropylene glycol methyl ether and t-butyl An initiator solution consisting of 1 part of peroxy 2-ethylhexanoate was dropped into the reaction vessel in parallel over 3 hours. After completion of the dropping, aging was performed at the same temperature for 0.5 hours.

  Next, an initiator solution consisting of 5.0 parts of dipropylene glycol methyl ether and 0.3 part of t-butylperoxy 2-ethylhexanoate was dropped into the reaction vessel over 0.5 hours. After completion of the dropping, aging was performed at the same temperature for 2 hours.

  Further, using a solvent removal apparatus, 16.11 parts of the solvent was distilled off at 110 ° C. under reduced pressure (70 torr), and then 204 parts of ion-exchanged water and 7.1 parts of dimethylethanolamine were added to obtain a water-soluble acrylic resin. It was. The obtained acrylic resin solution had a non-volatile content of 30.0%, a solid content acid value of 40 mgKOH / g, and a hydroxyl value of 50 mgKOH / g.

Preparation of Hydrophobic Melamine Resin Water Dispersion (MFD-1 ) 50 parts of MFDG (methylpropylene diglycol, manufactured by Nippon Emulsifier Co., Ltd.) was added to the reaction vessel, and the temperature was raised to 130 ° C. while stirring in a nitrogen stream. Next, an ethylenic polymer consisting of 14.77 parts of acrylic acid, 32.48 parts of 2-hydroxyethyl methacrylate, 47.75 parts of butyl acrylate, and 5 parts of MSD-100 (α-methylstyrene dimer, Mitsui Chemicals). A saturated monomer mixture and an initiator solution consisting of 13 parts of Kayaester O (tert-butyl peroctanoate, manufactured by Kayaku Akzo) and 10 parts of MFDG were dropped into the reaction vessel in parallel over 3 hours. After the completion of dropping, an initiator solution consisting of 0.5 parts of Kayaester O and 5 parts of MFDG was added dropwise over 0.5 hours. After completion of the dropwise addition, aging was performed at the same temperature for 1 hour. Subsequently, it was cooled to 50 ° C. to obtain an acrylic resin (Ac1) having a nonvolatile content of 60%, a solid content acid value of 110 mgKOH / g, a hydroxyl value of 140 mgKOH / g, and a number average molecular weight (Mn) = 3000.

  178.5 parts of the obtained acrylic resin (Ac1) was mixed with 800 parts of Uban 20SB (fully butylated melamine resin, Nippon Cytec Co., Ltd., non-volatile content 75%, Sp = 9.6), and 4 at 80 ° C. Stir for hours. Thereafter, 18.3 parts of dimethylethanolamine was added and dispersed uniformly. After cooling to 40 ° C., 1003.2 parts of ion-exchanged water was added dropwise over 1 hour, whereby a hydrophobic melamine resin aqueous dispersion (MFD-1) was added. ) The particle size of the resin particles in this aqueous dispersion was 80 nm.

Preparation of aqueous glittering base coating composition 153.3 parts of the above acrylic resin emulsion (Em-1) as a film-forming resin, 5 parts of a 10% by weight dimethylethanolamine aqueous solution, and 16. 7 parts, Prime Pole PX-1000 (Sanyo Chemical Industries, Ltd. bifunctional polyether polyol, number average molecular weight 1000, hydroxyl value 278, water tolerance infinity), 10 parts of the above hydrophobic melamine resin aqueous dispersion (MFD-1) ) 100 parts, pigment (a), color stream T20-04 WNT Lapis Sunlite (colorstream (registered trademark) T20-04 WNT Lapis Sunlight) (manufactured by MERCK, titanium dioxide-coated silica flake pigment, average particle size: 20 μm) ) As 6.63 parts, pigment (b), green G 0.24 parts of XL (manufactured by Clariant, phthalocyanine-based green organic coloring pigment, hue: 9.71G (Munsell hue ring)), cyanine blue 5206H (manufactured by Dainichi Seika Kogyo Co., Ltd., phthalocyanine-based blue organic coloring pigment) , Hue: 4.07 PB (Munsell hue ring)) and 2.23 parts of Raven 5000U3 (manufactured by Columbia Carbon Co., carbon black black colored pigment, Hue: 2.04Y (Munsell hue ring)) 21 parts were blended. Further, 1.26 parts of Alpaste 97-0510 (aluminum luster pigment manufactured by Toyo Aluminum Co., Ltd.) was added, 30 parts of ethylene glycol monohexyl ether was mixed and stirred, and 10% by mass aqueous dimethylaminoethanol solution was added to adjust the pH. = 8.5 and dispersed uniformly to obtain an aqueous glittering base coating composition. The resulting aqueous glittering base coating composition has a coating viscosity of 20 ° C. Ion-exchanged water was added and diluted so as to be 60 seconds in a 4 Ford cup to obtain a glittering base coating composition (1) used for coating.

Manufacture example 2: Preparation of glitter base coating composition (2) According to Manufacture example 1, instead of pigment (a), as a mica-based interference glitter pigment, Sileric T60-25WNT cosmic turquoise (average particle diameter) manufactured by MERCK : A bright base coating composition (2) for comparison was prepared using 6.63 parts of 18 μm).

Example 1
Dull steel plates (length 300 mm, width 100 mm and thickness 0.8 mm) were subjected to chemical conversion treatment using a zinc phosphate treatment agent ("Surfdyne SD2000", manufactured by Nippon Paint Co., Ltd.), followed by cationic electrodeposition coating ("Power Nix PN310 ”(manufactured by Nippon Paint Co., Ltd.) was electrodeposited so that the dry film thickness was 25 μm. Next, after baking at 160 ° C. for 30 minutes, as an intermediate coating material, polyester / melamine-based gray intermediate coating material (“Orga P-30”, manufactured by Nippon Paint Co., Ltd.) ethyl acetate / solvesso 100 / butyl diglycol acetate = 1 / 1/1 (weight ratio), Ford Cup No. 4 was adjusted so that the viscosity was 30 seconds, and the intermediate coating was performed using a rotary electrostatic coating machine, and baked and dried at 140 ° C. for 30 minutes. The intermediate coating film with an average dry film thickness of 30 μm A layer was formed.
Furthermore, the glittering base coating composition (1) prepared in Production Example 1 was spray-coated on the intermediate coating layer so that the average dry film thickness was 15 μm. The coating was performed using an electrostatic coating machine (“Auto REA”, manufactured by ABB Industry) at an atomization pressure of 2.0 kg / cm ² . The booth atmosphere during painting was maintained at a temperature of 25 ° C. and a humidity of 75%. After coating, set for 3 minutes, preheat at 80 ° C. for 5 minutes, and then wet-on-wet on top of the acrylic / melamine resin-based clear coating composition (acid epoxy curable acrylic resin-based clear coating composition (“Mac Flow O -1810 "(manufactured by Nippon Paint Co., Ltd.) was spray-coated to a dry film thickness of 35 μm, set at room temperature for 7 minutes, and baked at 140 ° C. for 30 minutes to form a glittering multilayer coating film ( 2 coats 1 bake (2C1B)).

Comparative Example 1
Instead of the glittering base coating composition (1) prepared in Production Example 1, the comparative glittering base coating composition (2) prepared in Production Example 2 was used, and A layer coating was formed.

  The following table shows the hue (H), lightness (V), and saturation (C) in the Munsell color system (JIS Z 8721) of the glittering multilayer coating films formed in the examples and comparative examples. The hue (H), lightness (V), and saturation (C) in the Munsell color system of the coating film were scaled in 1943 by the Colorimetry Committee of the Optical Society of America. The color sample of the color chart collection was determined by visual evaluation of the obtained coated plate.

  In Example 1 of the present invention, a change in hue over a wide range of “10Y to 10B” was observed, but in Comparative Example 1, only a hue of “5BG”, that is, a hue based on the pigment (b) can be observed. There wasn't.

  Moreover, the hue change and the interference width according to the angle of the glittering multilayer coating film were evaluated as follows.

  The hue which changes according to the angle of the glittering multilayer coating film formed in the example or the comparative example was measured using a colorimeter “Goniometer GCMS-4 (trade name)” manufactured by Murakami Color Research Laboratory. As shown in FIG. 3, the coating film was irradiated with light at incident angles of 30 °, 45 °, and 60 °, and for each incident light, a light receiving angle in the range of −80 ° to + 80 ° (in increments of 5 °, The chromaticity values a * and b * of the L * a * b * color system were measured at 99 points in total. The chromaticity a * value indicates that red increases as the a * value (+ a *) increases in the positive direction, and green increases as the a * value (−a *) increases in the negative direction. It shows that. The chromaticity b * value indicates that yellow increases as the b * value (+ b *) increases in the positive direction, and blue increases as the b * value (−b *) increases in the negative direction. It shows that. The results are shown in the table below.

  The a * value is taken on the horizontal axis, the b * value is taken on the vertical axis, and the values measured under each measurement condition are plotted (FIGS. 4 and 5).

  FIG. 4 is a graph in which a * values and b * values are plotted with respect to the glittering multilayer coating film formed in Example 1. When the detection limit is (a *, b *) = (0, 0), the detection number (a *, b *) = (− 31.97, 3.54) and the measurement number 99 (A *, b *) = (− 13.02, −22.29), and the detection limit is indicated by a solid line in FIG. 4.

  In the glittering multilayer coating film of Example 1 shown in FIG. 4, the value of a * is distributed in the minus direction along the horizontal axis, which indicates that the coating film is green. Moreover, in the glittering multilayer coating film of Example 1 shown in FIG. 4, the value of b * may be distributed in the positive direction, which means that the coating film is yellowish and has a green color close to yellow. [Refer to measurement number 21, (a *, b *) = (− 31.97, 3.54), which is the detection limit]] (10Y of Munsell hue ring (20 hues)). Furthermore, in the glittering multilayer coating film of Example 1 shown in FIG. 4, the value of b * may be distributed in the negative direction, which means that the coating film is bluish and exhibits a green color close to blue. [Refer to measurement number 99 (a *, b *) = (− 13.02, −22.29), which is the detection limit]] (Munsell hue ring (20 hues) 10B).

  FIG. 5 is a graph in which a * values and b * values are plotted with respect to the glittering multilayer coating film formed in Comparative Example 1. The detection limit is (a *, b *) = (− 30.73, −4.3) of measurement number 21 and measurement number 94 when (a *, b *) = (0, 0) is used as a reference. (A *, b *) = (− 16.91, −18.4), and the detection limit is shown by a solid line in FIG.

  In the glittering multilayer coating film of Comparative Example 1 shown in FIG. 5, the value of a * is distributed in the negative direction along the horizontal axis, which indicates that the coating film is green (ie, 5 GB). . However, in the glittering multi-layer coating film of Comparative Example 1 shown in FIG. 5, the value of b * is not distributed in the positive direction, and is never yellowish. Further, although the value of b * may be distributed in the negative direction, even if the detection limit [(a *, b *) = (− 16.91, −18.4) of measurement number 94]] There is no strong taste. Therefore, the glittering multilayer coating film of Comparative Example 1 exhibits a green hue (that is, 5 GB), but the hue does not change greatly in the green system depending on the angle.

  Also, this means that a line connecting (a *, b *) = (− 31.97, 3.54) of measurement number 21 and the origin (0, 0) shown in FIG. The angle between (a *, b *) = (− 13.02, −22.29) and the straight line connecting the origin (0, 0) is (a *, b *) of measurement number 21 shown in FIG. b *) = (− 30.73, −4.3) and the origin (0,0) and (a *, b *) = (− 16.91, −18. This is apparent from the fact that the angle is larger than the angle between 4) and the straight line connecting the origin (0, 0).

  Furthermore, even when the incident angle of light is 60 °, the present invention does not impair the glittering shine regardless of whether the light receiving angle is + 80 ° or −80 °, and wide interference. Could provide width.

In the method of the present invention, the hue of the titanium dioxide-coated silica flake pigment (a) having a specific particle size and the color pigment (b) are blended into the paint at specific blending amounts, respectively, so that the hue is close to yellow. Synchronous with other bright pigments and clear paint layers that can be included in the bright paint film in the highlight area of the object to be continuously changed to green close to blue within the same color of the green series. A glittering multilayer coating film having a unique design that does not exist in the past can be obtained, which looks like a gold color due to the effect, and looks like a blue color depending on the contrast with the highlight portion and the light intensity in the shade portion. In addition, according to the method of the present invention, a glittering glitter can be observed over a wide angle.
Therefore, the method of the present invention is particularly useful when applied to an object to be coated having a complicated shape such as an automobile body and whose design is very important as a product, in particular, an automobile body. The method of the present invention is not limited to automobile bodies, and can be applied to all painting fields.

1 Painted object 2 Highlight part 3 Shade part 4 Intermediate part 5 Incident light

Claims (5)

A method for forming a glittering multilayer coating film, wherein a glittering base coating film layer is formed on a substrate on which a base coating film layer is formed, and further a clear coating film layer is formed thereon,
In the Munsell color system, the glittering multi-layer coating film has a 10Y to 10B green hue of the Munsell hue ring (20 hues), a lightness (V) of 1 to 5, and a saturation of 1 to 6 (C )
The glittering base coating composition for forming the glittering base coating layer contains a titanium dioxide-coated silica flake pigment (a) having an average particle size of 5 to 40 μm and a coloring pigment (b),
The concentration (PWC) of the pigment (a) is 0.1 to 20% by mass,
The concentration (PWC) of the pigment (b) is 0.1 to 20% by mass,
The pigment (a) plays yellow, green and blue continuously,
A method for forming a glittering multilayer coating film.   The method according to claim 1, wherein the mass ratio ((a) / (b)) of the pigments (a) and (b) is 9/1 to 1/9.   3. The method according to claim 1, wherein the glittering multilayer coating film has a green hue of 5G to 10BG in a Munsell hue ring (20 hues).   The method according to claim 1, wherein the glittering multilayer coating film has a wide interference width.   A glittering multilayer coating film comprising the glittering base coating film layer and the clear coating film layer, which is formed by the method according to any one of claims 1 to 4.

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