JP2011136317A - 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 special design, in which a color phase changes continuously in similar colors of blue from a color phase of sky-blue system to a color phase of Armenian blue system according to a viewing angle, and further, which not only coruscates with a high colorfulness in case of viewing from the front face of an coated article, that is, in a highlight part, but also can coruscate with a high colorfulness in the case of viewing from the skew of the coated article, that is, also in a shade part. <P>SOLUTION: The method of forming the bright multilayer coating film comprises forming a bright base coating film layer on a substrate on which a ground coat layer is formed and further forming a clear coating layer thereon. The concentration of a brilliant pigment and a color pigment, and a particle diameter are prescribed such that the bright multilayer coating film have a predetermined color phase, lightness, and chroma in the Munsell color system. <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 Application Laid-Open No. 2002-275421 (Patent Document 1) discloses the use of a metal oxide-coated alumina flake pigment and a mica pigment as a bright pigment. In addition, by setting the ratio of the average particle diameter of the metal oxide-coated alumina flake pigment to the average particle diameter of the mica pigment within a specific range, the glittering and three-dimensional glittering feeling due to the multi-directional reflection, and the dense feeling It is possible to form a glittering coating film having both a white taste and a white taste.

  Japanese Patent Application Laid-Open No. 2003-73620 (Patent Document 2) forms an interference base clear coat layer by applying a glitter coating composition containing two or more interference glitter pigments on a color base coating film, Disclosed is a method of forming a coating film on which a top clear coat layer is formed. According to this method, it is possible to form a coating film expressing a trichromatic design depending on the viewing angle.

  JP-A-2003-73621 (Patent Document 3) forms an interference glittering base coat layer by applying a glittering paint composition containing two or more kinds of interference glittering pigments on a color base coating film, A glittering coating film forming method for forming a top clear coat layer thereon is disclosed. According to this method, it is possible to form a coating film that expresses a three-dimensional, glittering glittering feeling having an interference action.

  Japanese Patent Application Laid-Open No. 2005-239801 (Patent Document 4) discloses a metallic coating composition that uses two types of aluminum flake pigments having different particle diameters and further defines the blending amounts thereof. Further, when this metallic coating composition is used, a metallic coating film satisfying all of the particle feeling, glitter feeling, flip-flop property and concealing property is formed by a highly productive wet-on-wet 2-coat 1-bake coating method. be able to.

  Japanese Unexamined Patent Publication No. 2007-70424 (Patent Document 5) discloses a metallic coating composition containing two types of titanium oxide-coated alumina flakes as a bright pigment. This metallic paint composition may further contain an interference pearl pigment. By this metallic paint composition, the appearance is high in highlight, high gloss, excellent in compactness, and less yellowish, that is, white pearl color. A coating film can be formed.

  Japanese Patent Application Laid-Open No. 2008-237939 (Patent Document 6) discloses a first base glittering paint containing two types of aluminum pigments having different particle diameters, a second base glittering paint containing a fine scaly pigment, and a clear Disclosed is a method for forming a metallic light-glossy coating film, in which a paint is sequentially applied. According to this method, it is possible to form a coating film having excellent opacity and a high level of pearly luster and metallic luster, as well as a three-dimensional luster feeling.

  However, these coating films are all silver-based including a metallic color or white-based including a pearl color.

  Traditionally, there has been a tendency for silver-based and white-based paint colors to be preferred in Japan, but recently, there has been a tendency to prefer more colorful glitter coatings, especially in countries other than Japan, such as Europe and the United States. Then, gold, yellow, green, blue, etc., and vivid colors (high saturation) and strong shine are very popular.

  However, the glitter coating generally has high saturation due to interference color in the so-called highlight area where light strikes well, but there is a tendency for the saturation to rapidly decrease in the so-called shade area where light does not strike well. is there. Moreover, in the dark-colored coating film containing blue, since black absorbs light, it was very difficult to obtain vividness (high saturation) in the shade portion.

JP 2002-275421 A Japanese Patent Laid-Open No. 2003-73620 Japanese Patent Laid-Open No. 2003-73621 JP 2005-239801 A JP 2007-70424 A JP 2008-237939 A

  An object of the present invention is to provide a method for forming a glittering multilayer coating film having an unprecedented unique design having a blue hue, and in particular, from a so-called sky blue hue to a group blue hue depending on the viewing angle. The hue changes continuously within the same color of the blue system, and when viewed from the front of the painted object, that is, not only shines with high saturation at the highlight part, but also when viewed from an oblique angle of the painted object, that is, An object of the present invention is to provide a method for forming a glittering multi-layer coating film having a unique design that has never existed before and can shine with high saturation even in a shade portion.

  As a result of intensive studies, the inventors have blended the paint with a specific amount of the glitter pigment (a) and the color pigment (b), respectively, and the reflected light is blue-based as the glitter pigment (a). At least two kinds of glitter pigments having different average particle diameters (a1) a titanium oxide-coated alumina flake pigment having an average particle diameter of 10 to 25 μm and (a2) a titanium oxide-coated mica flake pigment having an average particle diameter of 5 to 15 μm, By using at least a carbon black coloring pigment as the coloring pigment (b), the hue continuously changes from a so-called sky blue hue to a group blue hue within the same hue of the blue hue, and coating The present invention is completed by finding that a glittering multilayer coating film having an unprecedented blue-based unique design capable of shining with high saturation not only in the highlight portion of the object but also in the shade portion can be obtained. It came to. 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 blue hue (H) from a hue selected from 10BG to 10B in the Munsell hue ring (20 hues) to a hue selected from 10PB to 10P. And a lightness (V) of 0-5 and a saturation (C) of 0-8,
The glitter base coating composition for forming the glitter base coating film layer includes a glitter pigment (a) and a color pigment (b),
The pigment (a) includes an alumina flake pigment (a1) and a mica flake pigment (a2),
The pigment (a1) is a titanium oxide-coated alumina flake pigment whose reflected light has a blue average particle diameter of 10 to 25 μm,
The pigment (a2) is a titanium oxide-coated mica flake pigment having an average particle diameter of 5 to 15 μm whose reflected light is blue.
The concentration (PWC) of the pigment (a1) is 0.1 to 30% by mass,
The concentration (PWC) of the pigment (a2) is 0.1 to 30% by mass,
The total concentration (PWC) of the pigments (a1) and (a2) is 0.2 to 60% by mass, the pigment (b) is a carbon black coloring pigment, and the concentration (PWC) of the pigment (b) ) Is 0.1 to 20% by mass.

  In the method for forming a glittering multilayer coating film of the present invention, preferably, the reflected light of the pigment (a1) has a hue of 10BG to 10PB of a Munsell hue ring (20 hues), and the pigment (a2) The reflected light has a 5B to 5P hue of the Munsell hue ring (20 hues).

  In the method for forming a glittering multilayer coating film of the present invention, the mass ratio ((a1) / (a2)) of the pigments (a1) and (a2) is preferably 2/8 to 8/2.

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

  In the method for forming a glittering multilayer coating film of the present invention, 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 for forming the glittering multilayer coating film of the present invention.

  As described above, the glittering multi-layer coating film formed by the present invention has a hue of 10PB to 10P from a hue of 10BG to 10B (so-called "sky blue" system) of the Munsell hue ring (20 hues) depending on the viewing angle. Although the hue (H) changes continuously in a so-called “group blue” system, as shown in FIG. 2, the highlight portion (2) where the incident light (5) of the painted object (1) strikes well is viewed from the front. Viewed from Munsell hue ring (20 hues) 10BG to 10B hue (H) (so-called “sky blue”), and at least two kinds of glitters with different average particle diameters contained in the glitter coating film By the action of the pigment, the coating film can shine with high saturation. Therefore, when the glittering multi-layer coating film formed in the present invention is applied to an object having a complicated shape such as an automobile body, an effect of highlighting 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 coated article (1) shown in FIG. 2 develops a hue (H) of 10PB to 10P (so-called “group blue” system) of the Munsell hue ring (20 hues), and has a glittering property. By the action of the at least two kinds of glitter pigments having different average particle diameters contained in the coating film, the coating film can shine with high saturation even in the shade portion. Due to this effect, a high-saturation shine can be continuously expressed from the highlight portion (2) to the shade (3), and the design of the object to be coated can be further emphasized.

  Therefore, as shown in FIG. 2, the glittering multi-layer coating film formed in the present invention includes not only the highlight portion (2) of the article to be coated (1) but also the pseudo portion (3) and its intermediate portion ( Also in 4), it is possible to express a glittering, high-brilliant glitter and provide an excellent design to the coating film.

  Such an effect of the present invention is obtained by using at least two kinds of glitter pigments (a1) and (a2) having different average particle diameters as the glitter pigment. Even in 3), it is very surprising that an excellent high-saturation glitter can be expressed.

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 chromaticity diagram of an XYZ color system is shown. A method for measuring chromaticity is schematically shown.

  The present invention relates to a method for forming a glittering multi-layer coating film, wherein the hue of the coating film continuously changes from a sky blue system to a group blue system within the same color of the blue system, and is a shade part of a coated object. Furthermore, the present invention provides a glittering multilayer coating film having a unique design of a blue color having an unprecedented blue color and having a glittering feeling.

  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”.

  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 according to the present invention is 0 to 5, preferably 0 to 3.

  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 0 to 8, preferably 0 to 5.

  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.

  According to the Munsell color system (20 hues), the hue (H) of the glittering multi-layer coating film formed according to the present invention is from 10BG to 10B (so-called “sky blue” system) to 10PB to 10P (so-called It changes slowly and continuously within a blue hue system of preferably 10BG to 10P.

  Furthermore, in the present invention, as shown in FIG. 2, the highlight (2) of the painted object (1) is well exposed to the light (5), so that a glittering high-saturation radiance appears very strongly. Surprisingly, in the invention, even in the shade portion (3) where the light does not strike well, an excellent high chroma glitter can be obtained. Therefore, in the present invention, it is possible to impart a glittering high-saturation glitter to the coating film over a wider range than before. In the present specification, such a wide range of glitter is sometimes referred to as a “wide interference width”. Also, it has been impossible with the prior art to achieve such a “wide interference width” with the above-described blue hue. This is because, in the conventional technology, when using a mica having a large particle diameter, which is generally well-known as a bright pigment that causes interference, the interference force becomes strong, but interference concentrates only in the highlight portion, and in the shade portion. Because of the fact that no interference occurs and mica having a small particle size, the interference force is weak, so that it is impossible to achieve a “wide interference width” with the prior art.

  As described above, the present invention covers from the hue selected from 10BG to 10B of the Munsell hue ring (20 hues) (so-called “sky blue” system) to the hue selected from 10 PB to 10P (so-called “group blue” system). It is possible to provide an unprecedented unique design with a blue interference hue (H) that has a wide interference width, but these features are included in the glittering multilayer coating. The glittering base coating composition for forming the glittering base coating film layer includes the glittering pigment (a) and the colored pigment (b) in specified amounts, respectively, and the reflected light is used as the glittering pigment (a). At least two kinds of bright pigments having different average particle diameters of blue type (a1) titanium oxide-coated alumina flake pigments having an average particle diameter of 10 to 25 μm and (a2) titanium oxide-coated mica flake pigments having an average particle diameter of 5 to 15 μm are used And The coloring pigment (b) can be achieved by using at least a carbon black coloring pigment in a specified amount. 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 blue hue (H) from 10BG to 10B of the Munsell hue ring (20 hues) shown in FIG. 1 to 10PB to 10P. , And lightness (V) of 0 to 5 and saturation (C) of 0 to 8, and the hue continuously changes within a blue-based similar color according to the angle, and only in the highlight portion In addition, the present invention provides an unprecedented unique design having an excellent glitter feeling even in the shade portion.

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, the term “brilliant paint composition” may be simply referred to as “vehicle” and “brilliant pigment (a)” (hereinafter referred to as “pigment (a)”). And a coloring pigment (b) [hereinafter sometimes abbreviated as “pigment (b)”] in specific amounts.

  In the present invention, by forming a glittering coating layer from a glittering coating composition containing pigment (a) and pigment (b) in specific amounts, respectively, 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 of the blue system according to the angle.

  Further, in the present invention, as the pigment (a), at least two kinds of bright pigments having reflected light having a blue average particle diameter are used. For example, alumina flake pigment (a1) [herein, And a mica flake pigment (a2) [hereinafter sometimes abbreviated as “pigment (a2)”] in some cases. To do. Furthermore, the present invention is characterized in that a carbon black coloring pigment is used as the pigment (b). In the present invention, the pigment (a1), the pigment (a2), and the pigment (b) concentration (Pigment Weight Concentration (PWC)) are regulated to specific values, respectively, so that a blue hue (H) is obtained. Excellent glitter can be achieved even in the shade portion.

As a first condition for expressing an excellent glitter feeling (that is, a wide interference width) not only in the highlight portion but also in the shade portion, the glitter pigment (a)
The pigment (a) includes an alumina flake pigment (a1) and a mica flake pigment (a2),
The pigment (a1) is a titanium oxide-coated alumina flake pigment whose reflected light has a blue average particle diameter of 10 to 25 μm,
The pigment (a2) is a titanium oxide-coated mica flake pigment having an average particle diameter of 5 to 15 μm whose reflected light is blue.
The concentration (PWC) of the pigment (a1) is 0.1 to 30% by mass,
The concentration (PWC) of the pigment (a2) is 0.1 to 30% by mass,
It is mentioned that the total concentration (PWC) of the pigments (a1) and (a2) is 0.2 to 60% by mass.

As a second condition, regarding the color pigment (b),
The pigment (b) is a carbon black coloring pigment,
The density | concentration (PWC) of a pigment (b) is 0.1-20 mass%.

Bright pigment (a)
In the present invention, as a glitter pigment (a) which can be blended in a glitter paint composition and can give a glittering glitter feeling to the coating film, the reflected light is at least two kinds having different blue average particle diameters. Add bright pigment. Therefore, in the present invention, as the glitter pigment (a), for example, the titanium oxide-coated alumina flake pigment (a1) [hereinafter referred to as pigment (a1)] whose reflected light has a blue average particle diameter of 10 to 25 μm and reflected light Is blended with the glitter paint composition with a blue-based titanium oxide-coated mica flake pigment (a2) [hereinafter referred to as pigment (a2)] having an average particle diameter of 5 to 15 μm.

Pigment (a1)
The pigment (a1) that can be used in the present invention can be produced by desirably uniformly coating titanium dioxide (TiO ₂ ) on natural or synthetic alumina flakes (aluminum oxide: Al ₂ O ₃ ). .

  The thickness of the alumina flake base material is 100 to 800 nm, preferably 200 to 400 nm. If the thickness of the alumina flake substrate deviates from the above range, the color developability defined in the present invention may be lowered.

  The composition of the pigment (a1) is 47.0 to 52.0% by mass of alumina; 42.0 to 47.0% by mass of titanium dioxide; 1.0 to 3.0% by mass of tin dioxide; 0.0 to 3.0% by mass; and silicon dioxide is 1.0 to 3.0% by mass (provided that the total is 100% by mass). When the pigment (a1) has such a composition, 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 (a1) is 10 to 25 μm, preferably 15 to 20 μm. If the average particle size deviates from the above range, the color developability defined in the present invention may not be achieved.

The average particle size of the pigment (a1) is a median value (D ₅₀ ) measured by a particle size distribution by a laser diffraction method.

  The pigment (a1) can express blue reflected light by having the above structure. In the present invention, the reflected light of the pigment (a1) preferably has a hue of 10BG to 10PB in the Munsell hue ring (20 hues), more preferably a hue of 10B to 10PB.

  In addition, the pigment (a1) may be a commercially available product, and examples thereof include Sileric T60-23 WNT Galaxy Blue, T60-25 WNT Cosmic Turquoise manufactured by MERCK. Among these, SILALIC T60-23 WNT Galaxy Blue manufactured by MERCK, whose reflected light is blue, is particularly preferable from the viewpoint of blue hue.

  In the present invention, two or more pigments (a1) may be used in combination.

  The concentration (PWC) of the pigment (a1) is 0.1 to 30% by mass, preferably 0.1 to 10% by mass in the glittering base coating composition. If the amount exceeds 30% by mass, the finished appearance may be deteriorated.

  In the present invention, the concentration (PWC) of the pigment (a1) represents the mass of the pigment (a1) 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 pigments (a1) and (a2) and pigment (b), a resin component (solid content) that serves as a vehicle for the glittering base coating composition, and any other components. All components (solid content) are included.

Pigment (a2)
The pigment (a2) that can be used in the present invention can be produced by desirably uniformly coating titanium dioxide (TiO ₂ ) on natural or synthetic mica flakes.

  The thickness of the mica flake layer is 100 to 800 nm, preferably 200 to 400 nm. If the thickness of the mica flake layer deviates from the above range, the color developability may be lowered.

  The composition of the pigment (a2) is 30 to 35% by mass of mica (mica); 60 to 65% by mass of titanium dioxide; 2.0 to 4.0% by mass of tin dioxide; and 1.0 to 3 of zirconium dioxide. 0.0 mass% (however, the total is 100 mass%). When the pigment (a2) has such a composition, the color development property defined in the present invention can be achieved.

  The thickness of the titanium dioxide layer is 50 to 300 nm. When the thickness of the titanium dioxide layer deviates from the above range, there is a possibility that the color development property defined in the present invention cannot be achieved.

The average particle diameter (D ₅₀ ) of the pigment (a2) is 5 to 15 μm, preferably 8 to 12 μm. If the average particle size deviates from the above range, the color developability defined in the present invention may not be achieved.

The average particle size of the pigment (a2) is a median value (D ₅₀ ) measured by a particle size distribution by a laser diffraction method.

  The pigment (a2) can express blue reflected light by having the above structure. In the present invention, the reflected light of the pigment (a2) preferably has a 5B to 5P hue of the Munsell hue ring (20 hues), more preferably a hue of 5PB to 5P.

  The pigment (a2) may be a commercially available product, and examples thereof include MERCK's Effect Pigment T81-23 WNT Liquid Blue. Especially, the effect pigment T81-23 WNT liquid blue made from MERCK whose reflected light is a blue system is especially preferable from a viewpoint of the high chroma of the coating film obtained.

  In the present invention, two or more pigments (a2) may be used in combination.

  The concentration (PWC) of the pigment (a2) is 0.1 to 30% by mass, preferably 0.1 to 10% by mass in the glittering base coating composition. If the amount exceeds 30% by mass, the finished appearance may be deteriorated.

  In the present invention, the concentration (PWC) of the pigment (a2) represents the mass of the pigment (a2) 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 pigments (a1) and (a2) and pigment (b), a resin component (solid content) that serves as a vehicle for the glittering base coating composition, and any other components. All components (solid content) are included.

  The total concentration (PWC) of the pigments (a1) and (a2) is 0.2 to 60% by mass, preferably 0.2 to 30% by mass. If the total concentration (PWC) is less than 0.2% by mass, the color developability may be lowered, and if it exceeds 60% by mass, the finished appearance may be lowered.

  Furthermore, the mass ratio ((a1) / (a2)) of the pigment (a1) and the pigment (a2) is 2/8 to 8/2, preferably 4/6 to 6/4, and less than 2/8. If it exists, the color developability at the highlight portion may be lowered, and if it exceeds 8/2, the color developability at the shade portion may be lowered.

  In the present invention, as described above, as the bright pigment (a), at least two kinds of pigments (a1) and pigment (a2) having different average particle diameters are blended (desirably, the average particle diameter ( a1)> (a2)). In the present invention, the glittering coating film includes at least two kinds of pigments (a1) and pigments (a2) having different average particle diameters, so that the wide interference width, that is, not only the highlight part but also the shade part. It is possible to achieve a brilliant feeling with excellent sparkle and high saturation. This is because, in the pigment (a1), when the average particle size is large, the reflected light is more concentrated in the regular reflection direction, and interference is strongly expressed in the highlight portion. In the pigment (a2), when the average particle size is small, It is considered that the reflected light is scattered in many directions and interference is strongly developed in the shade part.

Colored pigment (b)
In the present invention, at least a carbon black coloring pigment is blended in the glittering paint composition as the coloring pigment (b) together with the glittering pigment (a).

  The pigment (b) that can be used in the present invention is preferably a carbon black coloring pigment. In the present invention, a commercially available product may be used as it is. For example, Raven 5000U3 manufactured by Columbia Carbon Co. is preferable from the viewpoint of transparency.

  The concentration (PWC) of the pigment (b) is 0.1 to 20% by mass, preferably 0.1 to 10% by mass, and if it is less than 0.1% by mass, the base concealability in the case of forming a coating film If the amount exceeds 20% by mass, the finished appearance may be deteriorated.

  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 pigments (a1) and (a2) and pigment (b), a resin component (solid content) that serves as a vehicle for the glittering base coating composition, and any other components. Ingredients (solid content) are included.

  In the present invention, not only the pigment (a) and the pigment (b), but if necessary, other bright pigments other than the pigment (a) and the pigment (b), organic coloring pigments, inorganic pigments You may mix | blend pigments, such as a color pigment and extender, with a glittering base coating composition suitably.

Examples of other bright pigments other than pigment (a) include natural or synthetic alumina (Al ₂ O ₃ ) flakes or mica (mica) flakes, and metals other than titanium (eg, iron, chromium, cobalt, tin). , Zirconium, etc.), natural or synthetic silica (SiO ₂ ) flakes coated with oxides of, for example, titanium, iron, chromium, cobalt, tin, zirconium, etc.), metal aluminum flakes , Metal titanium flakes, stainless steel flakes, glass flakes and the like may be mentioned, and two or more kinds may be used in combination.

  Examples of organic colored 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, selenium pigments, perinone pigments, perylene pigments, indigo pigments, dioxane pigments, quinophthalone pigments, dioxazine pigments, metal complex organic pigments, etc. May be used.

  Examples of inorganic coloring pigments include titanium oxide, yellow lead, zinc white, cadmium red, molybdenum red, chromium yellow, chromium oxide, Prussian blue, cobalt blue, yellow iron oxide, bengara and the like. You may use it in combination.

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

  In the glittering base coating composition, the total pigment concentration (PWC) is 0.3 to 50% by mass, preferably 0.3 to 30% by mass. There is a possibility that the base concealing property is lowered, and when it exceeds 50% by mass, the finished appearance may be lowered.

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 the curing reaction is carried out at room temperature or at room 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, amber, 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. Further, these plastic molded articles are preferably those washed with steam or neutral detergent with trichloroethane. 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.

  If the base material is a base material having a base coating layer that has been subjected to base coating such as electrodeposition coating or intermediate coating, if necessary, 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 hue selected from 10BG to 10B of the Munsell hue ring (20 hues) (that is, a “sky blue” system) and a hue selected from 10PB to 10P ( That is, up to "group blue"), preferably 10BG-10P blue hue (H), and 0-5, preferably 0-3 lightness (V), and 0-8, preferably 0-5. Of saturation (C).

  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. From the hue (that is, “sky blue” system) selected from 10BG to 10B of the Munsell hue ring (20 hues) shown in FIG. Providing a blue hue (H) from 10P to a selected hue (i.e. a "group blue" series), as well as a lightness (V) of 0-5 and a saturation (C) of 0-8, Depending on the viewing angle, a hue change of at least three colors can occur within a blue-based similar color.

  The glitter (base) coating layer and the glittering multilayer coating film formed according to the present invention are characterized by having a wide interference width. That is, in the present invention, as the glitter pigment (a), preferably, at least two kinds of pigments (a1) and (a2) having different particle diameters are used in the above-mentioned prescribed amounts. The glittering sensation based on the interference of the reflected light spreads over the entire coating film. Surprisingly, not only the highlight portion (2) in FIG. 2, but also the shade portion (3) and its intermediate portion (4). In this case, it is possible to maintain an excellent glitter feeling with high saturation.

  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 multi-layer coating film formed by the present invention has a wide interference width, it is possible to confirm a sufficiently high-brilliant glittering sensation 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 Acrylic Resin Emulsion (Em-1) 135.4 parts of ion exchange water, Aqualon HS-10 (polyoxyethylene alkylpropenyl phenyl ether sulfate, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 1.1 The temperature was raised to 80 ° C. with 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.

Production Example 2: 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.

Production Example 3: 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. Warm up. 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.

Production Example 4: Preparation of glitter base coating composition (1) 153.3 parts of acrylic resin emulsion (Em-1) of Production Example 1 as a film-forming resin, 5 parts of 10% by weight dimethylethanolamine aqueous solution, production 16.7 parts of the water-soluble acrylic resin of Example 2, 10 parts of Prime Pol PX-1000 (bifunctional polyether polyol, number average molecular weight 1000, hydroxyl value 278, water tolerance infinite by Sanyo Chemical Industries), Production Example 3 100 parts of the hydrophobic melamine resin aqueous dispersion (MFD-1), and pigment (a1), 0 SILALIC T60-23 WNT Galaxy Blue (manufactured by MERCK, titanium dioxide-coated alumina flake pigment, average particle size: 18 μm) .5 parts, pigment (a2), effect pigment T81-23 WNT liquid blue (manufactured by MERCK, Titanium oxide-coated mica flake pigment, the average particle diameter: 0.5 parts of 9 .mu.m), (a b), carbon black (Columbia Carbon Co. Raven (Raven) pigment was blended 5000U3) 2.0 parts. Furthermore, 30 parts of ethylene glycol monohexyl ether was mixed and stirred, adjusted to pH = 8.5 by adding a 10% by mass dimethylaminoethanol aqueous solution, and uniformly dispersed 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 5: Preparation of glittering base coating composition (2) According to manufacture example 4, as a pigment (a1), as a pigment (a1), SILALIC T60-23 WNT Galaxy Blue (manufactured by MERCK, titanium dioxide-coated alumina flake pigment, average particle diameter: 18 μm ) As 5.0 parts, pigment (a2), 5.0 parts as effect pigment T81-23 WNT Liquid Blue (manufactured by MERCK, titanium dioxide-coated mica flake pigment, average particle size: 9 μm), as pigment (b) Carbon black (Raven 5000U3 manufactured by Columbia Carbon Co., Ltd.) was blended in 2.0 parts to obtain a glittering base coating composition (2).

Production Example 6: Preparation of glittering base coating composition (3) According to Production Example 4, Silica T60-23 WNT Galaxy Blue (manufactured by MERCK, titanium dioxide-coated alumina flake pigment, average particle diameter: 18 μm) as pigment (a1) 7.5 parts of pigment (a2), 7.5 parts of effect pigment T81-23 WNT Liquid Blue (manufactured by MERCK, titanium dioxide-coated mica flake pigment, average particle size: 9 μm), pigment (b) Carbon black (Raven 5000U3 manufactured by Columbia Carbon Co., Ltd.) was blended in 2.0 parts to obtain a glittering base coating composition (3).

Production Example 7: Preparation of glittering base coating composition (4) According to Production Example 4, Silica T60-23 WNT Galaxy Blue (manufactured by MERCK, titanium dioxide-coated alumina flake pigment, average particle size: 18 μm) as pigment (a1) ) And 1.0 part of pigment (a2), and 2.0 parts of carbon black (Raven 5000U3 manufactured by Columbia Carbon Co., Ltd.) as pigment (b). Property base coating composition (4) was obtained.

Production Example 8: Preparation of Glittering Base Coating Composition (5) According to Production Example 4, Silacic T60-23 WNT Galaxy Blue (manufactured by MERCK, titanium dioxide-coated alumina flake pigment, average particle diameter: 18 μm as pigment (a1) ) 10.0 parts, pigment (a2) is not blended, and pigment black (b) is blended with 2.0 parts of carbon black (Raven 5000U3 manufactured by Columbia Carbon Co., Ltd.). Property base coating composition (5) was obtained.

Production Example 9: Preparation of Glitter Base Coating Composition (6) According to Production Example 4, Silica T60-23 WNT Galaxy Blue (manufactured by MERCK, titanium dioxide-coated alumina flake pigment, average particle diameter: 18 μm as pigment (a1) ) 15.0 parts, pigment (a2) is not blended, and pigment black (b) is blended with 2.0 parts of carbon black (Raven 5000U3 manufactured by Columbia Carbon Co., Ltd.). Property base coating composition (6) was obtained.

Production Example 10: Preparation of glitter base coating composition (7) According to Production Example 4, pigments (a1) and (a2) were not blended, but instead, Iriodin 225 WNT (made by MERCK, mica) Pigment, average particle size: 18 μm) 10.0 parts, and pigment (b) as a pigment (b), 2.0 parts of carbon black (Raven 5000U3 manufactured by Columbia Carbon Co., Ltd.) is blended, and a glittering base paint for comparison A composition (7) was obtained.

Production Example 11: Preparation of glittering base coating composition (8) According to Production Example 4, Silica T60-23 WNT Galaxy Blue (manufactured by MERCK, titanium dioxide-coated alumina flake pigment, average particle size: 18 μm) as pigment (a1) ) And 5.0 parts of Iriodin 221 WNT (manufactured by MERCK, mica pigment, average particle size: 10 μm) as a substitute for pigment (a2), and carbon black (Colombia) as pigment (b) Raven 5000U3) manufactured by Carbon Co., Ltd. was blended with 2.0 parts to obtain a comparative glittering base coating composition (8).

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 PN 310 ”(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, a polyester / melamine gray intermediate coating material (“Olga 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 4 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)).

Example 2
According to Example 1, the glittering base coating composition (2) prepared in Production Example 5 was used instead of the glittering base coating composition (1) prepared in Production Example 4 in Example 1. A multilayer coating was formed.

Example 3
According to Example 1, the glittering base coating composition (3) prepared in Production Example 6 was used instead of the glittering base coating composition (1) prepared in Production Example 4 in Example 1. A multilayer coating was formed.

Comparative Example 1
According to Example 1, using the comparative glittering base coating composition (4) prepared in Production Example 7 instead of the glittering base coating composition (1) prepared in Production Example 4 in Example 1. A glittering multilayer coating film was formed.

Comparative Example 2
According to Example 1, using the comparative glittering base coating composition (5) prepared in Production Example 8 instead of the glittering base coating composition (1) prepared in Production Example 4 in Example 1. A glittering multilayer coating film was formed.

Comparative Example 3
According to Example 1, using the glittering base coating composition (6) for comparison prepared in Production Example 9 instead of the glittering base coating composition (1) prepared in Production Example 4 in Example 1. A glittering multilayer coating film was formed.

Comparative Example 4
According to Example 1, using the glittering base coating composition (7) for comparison prepared in Production Example 10 instead of the glittering base coating composition (1) prepared in Production Example 4 in Example 1. A glittering multilayer coating film was formed.

Comparative Example 5
Instead of the glittering base coating composition (1) prepared in Production Example 4 in Example 1, the comparative glittering base coating composition (8) prepared in Production Example 11 was used according to Example 1. A glittering multilayer coating film was formed.

  Further, the hue (H), lightness (V) and chroma (C) in the Munsell color system (JIS Z 8721) of the glittering multi-layer coating films formed in Examples and Comparative Examples are shown in the following table. The hue (H), brightness (V), and saturation (C) in the Munsell color system of the coating film were measured by “SM Color Computer SM-T” manufactured by Suga Test Instruments Co., Ltd.

  Further, the hue range (visual evaluation) of the glittering multi-layer coating films formed in the examples and comparative examples is a color chart whose scale was shown in 1943 by the colorimetry committee of the Optical Society of America. The color sample of the collection and the obtained coating plate were divided into cases where they were observed from two directions of the highlight position and the shade position, and were determined by carrying out a contrast evaluation by visual observation.

  The results are shown in the table below.

  The glittering multilayer coating films of Examples 1 to 3 of the present invention all exhibit a hue (H) of 10BG to 10B at the highlight position, and a hue (H) of 10PB to 10P at the shade position. Although a wide range of blue-based hue changes are continuously produced, none of the glittering multilayer coating films of Comparative Examples 1 to 5 show such hue changes at all.

Measurement of Chromaticity and Stimulus Purity The chromaticity (xy) in the XYZ color system (JIS Z 8701) of the glittering multilayer coating film formed in Examples and Comparative Examples was measured, and the stimulation purity (Pe) was calculated. The chromaticity (zy) of the XYZ color system is shown in FIG. 3 (chromaticity diagram).

  Using a multi-angle spectrophotometer “MA-68II” manufactured by Xrite, as shown in FIG. 4, light is irradiated at an incident angle of 45 °, and a light receiving angle of 15 ° (highlight), 25 Chromaticity (xy) was measured at °, 45 ° (intermediate), 75 ° and 110 ° (shade), respectively.

As shown in the chromaticity diagram of the XYZ color system (JIS Z 8701) in FIG. 3, the chromaticity coordinate of the actually measured sample is C (x, y), and the chromaticity coordinate of the achromatic color (that is, white) is N ( x _n , y _n ) = (0.3333, 0.3333), and the intersection of the straight line NC connecting N and C and the miracle of the chromaticity diagram is the chromaticity coordinate D (x _d , y _d ) (ie, color If the degree coordinate D is the pure chromaticity of the measured color), the stimulus purity (Pe) can be calculated according to the following formula (in detail, the figure in the appendix of JIS Z 8701) 1).
Pe = (x−x _n ) / (x _d −x _n ) × 100 (%)
Pe = (y− _{n n} ) / (y _d −y _n ) × 100 (%)
However, the stimulation purity (Pe) is obtained by the equation having the larger absolute value of the denominator of the above two equations.

  Therefore, the stimulus purity (Pe) indicates that the closer the value is to 100%, the higher the purity of the color, that is, the saturation. The saturation here is an index different from the saturation (C) of the Munsell color system.

  The measurement results of stimulation purity (Pe) are shown in the following table.

Evaluation of Stimulus Purity Generally, in a glittering coating film, the stimulation purity (saturation) decreases from a highlight portion (15 °) to an intermediate portion (45 °) and a shade portion (110 °). Therefore, the ratio (110 ° / 15 °) of the stimulus purity of the shade portion (110 °) to the highlight portion (15 °) is an index indicating how much saturation in the highlight portion can be maintained in the shade portion. It becomes.

As shown in Table 3 and Table 4, when Example 1 was compared with Comparative Example 1 (pigment (a2) not included), both had the same stimulation purity at the highlight portion (15 °) (51 In Example 1, the ratio to the highlight (110 ° / 15 °) is 0.12, and in Comparative Example 1, the ratio to the highlight (110 ° / 15 °) is 0. 0. In Example 1, it is shown that the saturation of 6 times that of Comparative Example 1 can be maintained.

  Moreover, when Example 2 and Comparative Example 2 (pigment (a2) not included) were compared, both showed the same value (66%) of stimulation purity at the highlight portion (15 °). In Example 2, the ratio to the highlight (110 ° / 15 °) is 0.30, and in Comparative Example 2, the ratio to the highlight (110 ° / 15 °) is 0.23. Then, it shows that the saturation in a shade part is improving clearly with respect to the comparative example 2. FIG.

  Furthermore, when Example 2 and Comparative Example 4 (pigments (a1) and (a2) were not included) were compared, the glittering multilayer coating film of Comparative Example 4 was found to have a conventional interference mica pigment “Iriodin 225 WNT (average In Example 2, the ratio to the highlight (110 ° / 15 °) is 0.30, whereas in Comparative Example 4, the ratio to the highlight is (110 ° / 15 °) is only 0.16, and Example 2 shows that the saturation in the shade portion is clearly improved compared to Comparative Example 4.

  Further, when Example 2 and Comparative Example 5 (pigment (a2) was replaced with conventional interference mica pigment) were compared, the glittering multilayer coating film of Comparative Example 5 was found to have a conventional interference mica pigment “Iriodin 221 WNT ( In Example 2, the ratio to the highlight (110 ° / 15 °) is 0.30, while in Comparative Example 5, the average particle size: 10 μm) ”is used. The ratio (110 ° / 15 °) is only 0.22, and Example 2 shows that the saturation in the shade portion is clearly improved compared to Comparative Example 5.

  Similarly, when Example 3 and Comparative Example 3 (pigment (a2) not included) were compared, both had substantially the same stimulus purity at the highlight portion (15 °) (67% in Example 3). In Comparative Example 3, the ratio to the highlight (110 ° / 15 °) is 0.36. In Comparative Example 3, the ratio to the highlight (110 ° / 15 °) is shown. 15 °) is 0.31, and Example 3 shows that the saturation in the shade portion is clearly improved as compared with Comparative Example 3.

  Therefore, in the present invention, not only the highlight portion but also the shade portion can maintain a glittering and high-brilliant glitter and maintain high saturation over a wide angle.

  Further, the glittering multilayer coating film of Comparative Example 4 does not contain pigments (a1) and (a2), and uses the conventional large particle size interference mica pigment “Iriodin 225 WNT (average particle size: 18 μm)”. Therefore, the ratio to the highlight (110 ° / 15 °) is 0.16, but the hue of the resulting glittering multilayer coating film is as wide as in the examples of the present invention as described above. It did not develop a hue change. Further, in the bright multilayer coating film of Comparative Example 4, a wide interference width as in the example of the present invention could not be observed.

  Furthermore, the glittering multilayer coating film of Comparative Example 5 does not contain the pigment (a2) and uses the conventional small particle size interference mica pigment “Iriodin 221 WNT (average particle size: 10 μm)”. As described above, the hue of the resulting glittering multilayer coating film did not exhibit a wide hue change as in the examples of the present invention. Further, in the glittering multilayer coating film of Comparative Example 5, a wide interference width as in the example of the present invention could not be observed.

In the method of the present invention, at least two kinds of pigments (a1) and (a2) having desirably different particle diameters as the bright pigment (a), and at least a carbon black coloring pigment as the coloring pigment (b) are specifically blended. By adding to the paint in an amount, the hue continuously changes from the sky blue to the ultramarine blue within the same color of the blue, and the excellent blue color between the highlight and shade parts of the paint. Thus, it is possible to form a glittering multilayer coating film having an unprecedented unique design. In addition, according to the method of the present invention, not only the highlight part of the coated object but also the shade part, a glittering and high-brilliant glittering sensation can be obtained, and such an excellent shining feeling can be obtained from the object to be coated. It can be observed over a wide angle.
Therefore, the method of the present invention is particularly useful when applied to an object having a complicated shape such as an automobile body and whose design is very important as a product. 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 (6)

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 blue hue (H) from a hue selected from 10BG to 10B in the Munsell hue ring (20 hues) to a hue selected from 10PB to 10P. And a lightness (V) of 0-5 and a saturation (C) of 0-8,
The glitter base coating composition for forming the glitter base coating film layer includes a glitter pigment (a) and a color pigment (b),
The pigment (a) includes an alumina flake pigment (a1) and a mica flake pigment (a2),
The pigment (a1) is a titanium oxide-coated alumina flake pigment whose reflected light has a blue average particle diameter of 10 to 25 μm,
The pigment (a2) is a titanium oxide-coated mica flake pigment having an average particle diameter of 5 to 15 μm whose reflected light is blue.
The concentration (PWC) of the pigment (a1) is 0.1 to 30% by mass,
The concentration (PWC) of the pigment (a2) is 0.1 to 30% by mass,
The total concentration (PWC) of the pigments (a1) and (a2) is 0.2 to 60% by mass, the pigment (b) is a carbon black coloring pigment, and the concentration (PWC) of the pigment (b) ) Is 0.1 to 20% by mass. The reflected light of the pigment (a1) has a Munsell hue ring (20 hues) 10BG to 10PB, and the reflected light of the pigment (a2) has a Munsell hue ring (20 hues) 5B to 5P hue. The method for forming a glittering multilayer coating film according to claim 1, comprising:   The method for forming a glittering multilayer coating film according to claim 2, wherein a mass ratio ((a1) / (a2)) of the pigments (a1) and (a2) is 2/8 to 8/2.   The method for forming a glittering multilayer coating film according to claim 3, wherein the glittering multilayer coating film has a blue hue (H) of 10BG to 10P in a Munsell hue ring (20 hues).   The method for forming a glittering multilayer coating film according to claim 4, 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 formed by the method for forming the glittering multilayer coating film according to any one of claims 1 to 5.

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