Multilayer coating film and coated article, and method for manufacturing coated article

Abstract

To provide a multilayer coating film that exhibits a calm gray color in a face region while enabling a chromatic tint to be sensed in a highlight region, a coated article including the multilayer coating film, and a method for producing the same.SOLUTION: A multilayer coating film includes a first coating film, a second coating film, and a clear coating film. The second coating film contains a scaly pigment coated with a metal oxide. The chroma C1*45 and the lightness L1*45 of the first coating film satisfy the relationships of C1*45≤15 and 20≤L1*45≤70. The lightnesses L1*15 and L1*110 satisfy the relationship of L1*15-L1*110≤15. The second coating film has an average light transmittance of 50% or more. The chroma Cm*15 and Cm*45 of the multilayer coating film satisfy the relationships of Cm*15>10 and Cm*15-Cm*45>5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a multi-layer coating and a coated article, as well as a method for producing the coated article. [Background technology]

[0002] The exterior of an automobile is usually provided with a multi-layer paint film. Patent Document 1 discloses a multi-layer paint film having a white paint film appearance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5213049 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, the diversification of consumer tastes and the pursuit of originality have led to a wide variety of designs being required for multi-layer coating films. The present invention aims to provide a multi-layer coating film with a design different from that of Patent Document 1, which presents a subdued gray color in the face area while showing a chromatic color in the highlight area. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention provides the following aspects. [1] A multi-layer coating film comprising a first coating film, a second coating film disposed on the first coating film, and a clear coating film disposed on the second coating film, the second coating film contains a flaky pigment coated with a metal oxide; Incident light I1 incident at an angle of 45 degrees to the surface of the first coating film 45 The reflected light R1 is received at an angle of 45 degrees to the specular reflection light. 45 L based on the spectral reflectance of * C * Chroma C1 in the h color system* 45 and lightness L1 * 45 but, C1 * 45 ≦15 20≦L1 * 45 ≦70 Fulfilling the relationship, The incident light I1 45 The reflected light R1 is received at an angle of 15 degrees to the specular reflection light. 15 L based on the spectral reflectance of * C * Lightness L1 in the h color system * 15 and the incident light I1 45 The reflected light R1 is received at an angle of 110 degrees to the specular reflection light. 110 L based on the spectral reflectance of * C * Lightness L1 in the h color system * 110 But, L1 * 15 -L1 * 110 ≦15 Fulfilling the relationship, The second coating film has an average light transmittance of 50% or more in the wavelength range of 400 nm to 700 nm, Incident light Im incident on the surface of the multilayer coating film at an angle of 45 degrees 45 The reflected light Rm is received at an angle of 15 degrees to the specular reflection light. 15 L based on the spectral reflectance of * C * Chroma Cm in the h color system * 15 and the incident light Im 45 The reflected light Rm is received at an angle of 45 degrees to the specular reflection light. 45 L based on the spectral reflectance of * C * Chroma Cm in the h color system * 45 But, Cm * 15 >10 Cm * 15-Cm * 45 >5 A multi-layer coating that satisfies the above relationship. [2] The second coating composition used to form the second coating film was applied to a black substrate, and incident light I2 was incident at an angle of 45 degrees to the surface of the test coating film obtained. 45 The reflected light R2 is received at an angle of 15 degrees to the specular reflection light. 15 L based on the spectral reflectance of * C * Chroma C2 in the h color system * 15 but, C2 * 15 ≧5 The multi-layer coating film of [1] above satisfies the relationship. [3] The multi-layer coating film of [1] or [2] above, wherein the content of the scale-like pigment is 0.5% by mass or more and 20% by mass or less of the second coating film. [4] the second coating further comprises a color pigment; The multi-layer coating film according to [1] or [2] above, wherein the content of the color pigment is 0.05% by mass or more and 1.5% by mass or less of the second coating film. [5] The multi-layer coating film according to [4] above, wherein the mass ratio of the scaly pigment to the color pigment is 2 or more and 400 or less. [6] The object to be coated A coated article having the multi-layer coating film of [1] above disposed on the substrate. [7] A method for producing a coated article having a multilayer coating film comprising a first coating film, a second coating film disposed on the first coating film, and a clear coating film disposed on the second coating film, Applying a first coating composition to a substrate to form the first coating film; Applying a second coating composition containing a scaly pigment coated with a metal oxide onto the first coating film to form the second coating film; and applying a clear coating composition onto the second coating film to form the clear coating film. Incident light I1 incident at an angle of 45 degrees to the surface of the first coating film 45 The reflected light R1 is received at an angle of 45 degrees to the specular reflection light. 45 L based on the spectral reflectance of * C * Chroma C1 in the h color system * 45 and lightness L1 * 45 but, C1 * 45 ≦15 20≦L1 * 45 ≦70 Fulfilling the relationship, The incident light I1 45 The reflected light R1 is received at an angle of 15 degrees to the specular reflection light. 15 L based on the spectral reflectance of * C * Lightness L1 in the h color system * 15 and the incident light I1 45 The reflected light R1 is received at an angle of 110 degrees to the specular reflection light. 110 L based on the spectral reflectance of * C * Lightness L1 in the h color system * 110 But, L1 * 15 -L1 * 110 ≦15 Fulfilling the relationship, the second coating film has an average light transmittance of 50% or more in the wavelength range of 400 nm to 700 nm; Incident light Im incident on the surface of the multilayer coating film at an angle of 45 degrees 45 The reflected light Rm is received at an angle of 15 degrees to the specular reflection light. 15 L based on the spectral reflectance of * C * Chroma Cm in the h color system * 15 and the incident light Im 45 The reflected light Rm is received at an angle of 45 degrees to the specular reflection light. 45 L based on the spectral reflectance of * C* Chroma Cm in the h color system * 45 But, Cm * 15 >10 Cm * 15 -Cm * 45 >5 A method for manufacturing a coated article that satisfies the above relationship. [Effects of the Invention]

[0006] According to the present invention, there are provided a multi-layer coating film that exhibits a subdued gray color in the face area while exhibiting a chromatic color in the highlight area, a coated article having this multi-layer coating film, and a method for manufacturing the same. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 10 is a diagram illustrating a light-receiving angle. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Multi-layer coating] The multi-layer coating film of the present disclosure comprises a first coating film, a second coating film disposed on the first coating film, and a clear coating film disposed on the second coating film. The second coating film contains a scaly pigment coated with a metal oxide.

[0009] Incident light I1 incident at an angle of 45 degrees to the surface of the first coating 45 The reflected light R1 is received at an angle of 45 degrees to the specular reflection light. 45 L based on the spectral reflectance of * C * Chroma C1 in the h color system * 45 and lightness L1 * 45 but, C1 * 45 ≦15 20≦L1 * 45 ≦70 Satisfy the relationship. This indicates that the first coating film is solid and in the gray color range.

[0010] The first coating also reflects incident light I1 45 The reflected light R1 is received at an angle of 15 degrees to the specular reflection light. 15 L based on the spectral reflectance of * C * Lightness L1 in the h color system * 15 and the reflected light R1 received at an angle of 110 degrees to the specular reflected light. 110 L based on the spectral reflectance of * C * Lightness L1 in the h color system * 110 But, L1 * 15 -L1 * 110 ≦15 Satisfy the relationship. This indicates that the first coating film has low flip-flop properties, and more specifically, that the first coating film is not a coating film that exhibits high flip-flop properties like metallic coating films.

[0011] The second coating film has an average light transmittance of 50% or more in the wavelength range of 400 nm to 700 nm. In other words, the second coating film has high light transmittance in the visible light range. This allows the color (gray) of the first coating film to be perceived through the second coating film. In other words, the color of the first coating film perceived through the second coating film can be perceived as a design of the multi-layer coating film.

[0012] The second coating film contains a scaly pigment coated with a metal oxide. Such scaly pigments exhibit optical coherence, so that their color appears to change depending on the viewing angle.

[0013] Incident light Im incident at a 45 degree angle on the surface of the multi-layer coating (the surface on the clear coating side) 45 The reflected light Rm is received at an angle of 15 degrees to the specular reflection light. 15 L based on the spectral reflectance of * C *Chroma Cm in the h color system * 15 and incident light Im 45 The reflected light Rm is received at an angle of 45 degrees to the specular reflection light. 45 L based on the spectral reflectance of * C * Chroma Cm in the h color system * 45 But, Cm * 15 >10 Cm * 15 -Cm * 45 >5 Satisfy the relationship. This indicates that the multi-layer coating film has a chromatic tint in the highlight area, and that the tint changes between the highlight area and the face area.

[0014] This disclosure combines a first coating film that is a solid gray color gamut with low saturation, specific lightness, and low flip-flop properties, with a second coating film that contains a light-interfering scale-like pigment (hereinafter sometimes referred to as a light-interfering pigment) and has optical transparency. By blending the light-interfering pigment in a coating film different from the first coating film, a new design can be expressed in which the face area presents a subdued solid gray color (achromatic color) while the highlight area has a chromatic color.

[0015] The highlight region refers to the range of -25 degrees or more and less than 25 degrees relative to the specular reflection of light incident at a 45-degree angle. The shade region refers to the range of 75 degrees or more relative to the specular reflection of light incident at a 45-degree angle. The face region is the range between the highlight region and the shade region (more than 25 degrees and less than 75 degrees relative to the specular reflection). In this disclosure, the highlight region is defined as the saturation at an angle of 15 degrees relative to the specular reflection, which can also be called the super highlight region.

[0016] Saturation C * 45 is the incident light I incident at an angle of 45 degrees to the surface of the target coating. 45The specular reflectance of the reflected light received at a 45-degree angle to the specular reflected light is calculated as L * C * This is the saturation in the h color system. * 15 is the incident light I 45 is defined as above, except that the specular reflection is received at an angle of 15 degrees. * C * In the h color system, saturation C * As the value increases, the vividness of the target coating increases, and as the value decreases, the dullness increases.

[0017] Lightness L * 45 is the incident light I incident at an angle of 45 degrees to the surface of the target coating. 45 The specular reflectance of the reflected light received at a 45-degree angle to the specular reflected light is calculated as L * C * Lightness in the h color system. Lightness L * 15 and lightness L * 110 is the incident light I 45 is defined as above, except that the specular reflection is received at an angle of 15 degrees or 110 degrees. * C * In the h color system, lightness L * As the value increases, the brightness of the target coating increases, and as the value decreases, the darkness increases.

[0018] L * C * h color system is CIEL * a * bColor system (CIE1976L * a * b * Calculated based on the CIE1976L color space. * a * b * The color space can be calculated in accordance with JIS Z 8781-4. * a *The b color system has been established by the International Commission on Illumination and is described in Section 4.2 of CIE Publication 15.2 (1986).

[0019] Saturation C * and lightness L * can be obtained using a spectrophotometer (for example, BYK-mac i manufactured by BYK Gardner).

[0020] Figure 1 is a diagram illustrating the light receiving angle. Incident light I is incident on the surface of the coating at an angle of 45 degrees. 45 The specular reflection of the incident light I is denoted by R0. 45 The reflected light received at an angle of 15 degrees to the incident light is R 15 Reflected light R 15 From the spectral reflectance of * 15 and saturation C * 15 is calculated. Incident light I 45 The reflected light received at a 45 degree angle to the incident light is R 45 Light R 45 From the spectral reflectance of * 45 and saturation C * 45 is calculated. Incident light I 45 The reflected light received at an angle of 110 degrees to the incident light is R 110 Reflected light R 110 From the spectral reflectance of * 110 is calculated.

[0021] (First coating) The first coating film is in the gray color range and gives the multi-layer coating film a gray hue. The first coating film is typically a cured product of a first coating composition containing a pigment for adjusting brightness (typically a white pigment and a black pigment) and a film-forming resin.

[0022] First coating saturation C1 *45 and lightness L1 * 45 teeth, C1 * 45 ≦15 20≦L1 * 45 ≦70 Satisfy the relationship.

[0023] Since the first coating film is in the gray color range, the properties of the optical interference pigment contained in the second coating film are exerted, and the multi-layer coating film produces the desired color in the highlight area.

[0024] C1 * 45 may be 12 or less, or may be 10 or less. * 45 may be 1.0 or greater, and may be 1.5 or greater.

[0025] L1 * 45 L1 may be 30 or more, or may be 40 or more. * 45 may be 67 or less, or may be 65 or less.

[0026] The spectral reflectance of reflected light R1 is measured for a single first coating film, not for a multi-layer coating film. A single first coating film refers to a cured coating film of a first coating composition applied to a substrate. A single first coating film is obtained by spray-painting a steel plate with a cationic electrodeposition paint and an undercoat paint, heating and curing each, and then spray-painting the first coating composition used to form the first coating film onto the substrate so that the dry coating film thickness is 3 μm to 20 μm (typically 15 μm), followed by heating and curing at 140°C for 20 minutes.

[0027] Lightness of the first coating L1 * 15 and lightness L1 * 110 What is that? L1 * 15 -L1 * 110 ≦15 Satisfy the relationship.

[0028] L1 * 15 -L1 * 110 L1 may be 12 or less, may be 10 or less, or may be 8 or less. * 15 -L1 * 110 may be 0 or may be 0.5 or greater.

[0029] L1 * 15 For example, L1 is between 20 and 80. * 15 L1 may be 30 or more, or may be 40 or more. * 15 may be 77 or less, and may be 75 or less.

[0030] L1 * 110 For example, L1 is between 10 and 70. * 110 L1 may be 20 or more, or may be 30 or more. * 110 may be 67 or less, or may be 65 or less.

[0031] The spectral reflectance of the reflected light R1 from the first coating film can be adjusted by, for example, the types and masses of various pigments contained in the first coating film and the thickness of the first coating film.

[0032] The thickness of the first coating film may be, for example, 3 μm or more and 20 μm or less. The thickness of the first coating film may be 7 μm or more. The thickness of the first coating film may be 15 μm or less, 14 μm or less, or 13 μm or less.

[0033] (Second coating) The second coating film contains a light-interference pigment. The light-interference pigment produces a chromatic color that changes depending on the viewing direction. Therefore, the color of the multi-layer coating film becomes more vivid from the face region to the highlight region. The second coating film is typically a cured product of a second paint composition containing a light-interference pigment and a film-forming resin.

[0034] The light transmittance of the second coating film can affect the design of the multilayer coating film. The second coating film has an average light transmittance of 50% or more at wavelengths of 400 to 700 nm. This allows the color of the first coating film to be perceived through the second coating film. The average light transmittance of the second coating film may be 60% or more, or may be 70% or more. The average light transmittance of the second coating film is, for example, 95% or less.

[0035] The average light transmittance of the second coating film is measured for the single second coating film, not for the multi-layer coating film. The single second coating film refers to a cured film of the second coating composition. The single second coating film is obtained by spray-coating the second coating composition onto a polypropylene plate so that the dry film thickness is 10 μm or more and 20 μm or less (typically 15 μm), heating and curing at 140°C for 20 minutes, and then peeling the coating film from the polypropylene plate.

[0036] The light transmittance of the second coating film alone is measured using a spectrophotometer (e.g., Hitachi, product name: U-4100) in the range of 400 to 700 nm in wavelength scan mode at a scan speed of 60 nm / min and a sampling interval of 2 nm. The arithmetic mean value of the obtained light transmittances every 10 nm is defined as the average light transmittance.

[0037] Incident light I2 incident at an angle of 45 degrees on the surface of the test coating film obtained by applying the second coating composition to a black substrate 45 The reflected light R2 is received at an angle of 15 degrees to the specular reflection light. 15 L based on the spectral reflectance of * C * Chroma C2 in the h color system * 15 teeth, C2 *15 ≧5 The following relationship may be satisfied. In other words, the second coating film itself can have a chromatic color in the highlight area. * 15 is likely to be greater than 10.

[0038] C2 * 15 may be 7 or more, or may be 10 or more. * 15 may be 50 or less, or may be 40 or less.

[0039] The black substrate has a black area conforming to the hiding power test paper specified in 3.2 of JIS K 5101-4:2004 Pigment Test Methods - Part 4: Hiding Power - Hiding Power Test Paper Method. Specifically, it is an approximately 174mm x 144mm art paper with white and black areas coated with a solvent-resistant transparent paint, and the 45° and 0° diffuse reflectance is 80±1 for the white area and 2 or less for the black area.

[0040] Average light transmittance of the second coating and reflected light R2 15 The spectral reflectance can be adjusted, for example, by the types and masses of various pigments contained in the second coating film and the thickness of the second coating film.

[0041] The content of the optical interference pigment may be 0.5% by mass or more and 20% by mass or less of the second coating film. This allows the light transmittance and reflected light R2 of the second coating film to be improved. 15 In addition, when the content of the optical interference pigment is 20% by mass or less, the surface of the second coating film is easily made smooth, and deterioration in the appearance of the multilayer coating film is suppressed.

[0042] The content of the optical interference pigment may be 0.8% by mass or more, or 1.0% by mass or more, and may be 15% by mass or less, 12% by mass or less, or 10% by mass or less.

[0043] The second coating film may further contain a color pigment. The color of the second coating film reduces color unevenness that may occur when the thickness of the first coating film and / or the second coating film is uneven.

[0044] The content of the color pigment may be 0.05% by mass or more and 1.5% by mass or less of the second coating film so as not to interfere with the light interference of the light interference pigment. The content of the color pigment may be 0.1% by mass or more, or 0.2% by mass or more. The content of the color pigment may be 1.3% by mass or less, 1.0% by mass or less, or 0.9% by mass or less.

[0045] The mass ratio of the optical interference pigment to the color pigment (optical interference pigment / color pigment) may be 2 or more and 400 or less. This makes it difficult for the optical interference pigment to inhibit the appearance of interference colors. The mass ratio may be 10 or more, or 20 or more. The mass ratio may be 300 or less, 200 or less, or 75 or less.

[0046] The primary particle diameter of the color pigment is not particularly limited. The primary particle diameter of the color pigment may be 3 nm or more and 500 nm or less, so that the appearance of the interference color by the light interference pigment is not easily hindered. The primary particle diameter can be measured using image processing software from an electron microscope image of the cross section of the multilayer coating film.

[0047] The thickness of the second coating film may be, for example, 3 μm or more and 23 μm or less, 7 μm or more, 20 μm or less, or 17 μm or less.

[0048] Optical interference pigments Optical interference pigments have a scaly base material and a metal oxide coating on its surface. Because the refractive index of the base material and the metal oxide differ, multiple reflections of light occur, resulting in the appearance of interference colors. Optical interference pigments can be used alone or in combination of two or more types.

[0049] Examples of the substrate include mica, artificial mica, glass, silica, iron oxide, and aluminum oxide. Among them, mica, artificial mica, and aluminum oxide are preferred.

[0050] The term "scaly" refers to a shape having an aspect ratio (average major axis / average thickness) of more than 1.0. The aspect ratio of the optical interference pigment is, for example, 20 or more and 300 or less. The aspect ratio of the optical interference pigment may be 30 or more. The aspect ratio of the optical interference pigment may be 200 or less.

[0051] The average major axis of the optical interference pigment is obtained by observing the optical interference pigment with a shape analysis laser microscope (for example, Keyence VK-X 250) and averaging the major axes (maximum lengths) of 100 arbitrarily selected optical interference pigments. The average thickness of the optical interference pigment is obtained by observing the cross section of a coating film containing the optical interference pigment with a transmission electron microscope (TEM) and averaging the thicknesses of 100 arbitrarily selected optical interference pigments.

[0052] The average particle size of the optical interference pigment is, for example, 3 μm or more and 15 μm or less, or 4 μm or more, or 5 μm or more, or 12 μm or less, or 10 μm or less.

[0053] The average particle size is the 50% average particle size (D50) in the volumetric particle size distribution measured using a laser diffraction / scattering particle size distribution analyzer, such as the UPA-150 (Microtrac particle size distribution analyzer, manufactured by Nikkiso Co., Ltd.).

[0054] Examples of metal oxides include titanium oxide and iron oxide. The thickness of the metal oxide coating is not particularly limited and may be selected appropriately depending on the desired interference color. The interference color varies depending on the thickness of the coating. The saturation of the second coating film and the multi-layer coating film may change depending on the thickness of the coating.

[0055] The optical interference pigment may be further subjected to a surface treatment for the purpose of improving dispersibility, water resistance, chemical resistance, weather resistance, and the like.

[0056] The optical interference pigment is not particularly limited as long as it exhibits the physical properties of the second coating film of the present disclosure. Specific examples of the optical interference pigment include metal oxide-coated mica and metal oxide-coated alumina flakes.

[0057] Commercially available metal oxide-coated mica products include, for example, the "Ultimica" series and "TWINCLE PEARL" series manufactured by Nihon Koken Kogyo Co., Ltd., the "Automotive" series manufactured by CQV, the "Lumina" series and "Magna Pearl" series manufactured by BASF, and the "IRIODIN" series manufactured by MERCK.

[0058] Commercially available metal oxide-coated alumina flakes include, for example, the "Xirallic" series manufactured by MERCK and the "Adamas" series manufactured by CQV.

[0059] Color pigments Color pigments absorb, reflect, or scatter light to impart color to coating films. Color pigments may be inorganic or organic. Color pigments may be chromatic or achromatic. Examples of organic color pigments include azo chelate pigments, insoluble azo pigments, condensed azo pigments, diketopyrrolopyrrole pigments, phthalocyanine pigments, indigo pigments, perinone pigments, perylene pigments, dioxane pigments, quinacridone pigments, isoindolinone pigments, and metal complex pigments. Examples of inorganic color pigments include yellow lead, yellow iron oxide, red iron oxide, carbon black, and titanium dioxide. These may be used alone or in combination of two or more.

[0060] (clear coating) The clear coating protects the first and second coatings and is typically a cured product of a clear coating composition.

[0061] The thickness of the clear coating film may be, for example, 10 μm or more and 80 μm or less, 20 μm or more, or 50 μm or less.

[0062] (Saturation and brightness of multi-layer coating) Saturation Cm * 15 may be 12 or more, or may be 13 or more. * 15 may be 50 or less, may be 40 or less, or may be 35 or less.

[0063] Saturation Cm * 45 may be 10 or less, or may be 9.0 or less. * 45 may be 1.0 or greater, and may be 1.1 or greater.

[0064] Cm * 15 -Cm * 45 may be 5.5 or more, or may be 6.0 or more. * 15 -Cm * 45 may be 50 or less, may be 40 or less, or may be 30 or less.

[0065] Lm * 45 For example, Lm is between 30 and 65. This makes the face area appear gray. * 45 Lm may be 32 or more, and may be 35 or more. * 45 may be 65 or less, or may be 62 or less.

[0066] [Painted items] The coated article according to the present disclosure comprises a substrate and the above-described multilayer coating film disposed on the substrate. In the coated article, the clear coating film is disposed on the outside. The coated article having the above-described multilayer coating film has a unique design in which the face region exhibits a subdued gray color while the highlight region exhibits a chromatic color.

[0067] (subject to be coated) Examples of materials for the substrate include metals, plastics, and foams. Metals (particularly cast metals) are particularly suitable, and metals that can be electrocoated are also suitable. Examples of such metals include iron, copper, aluminum, tin, zinc, and alloys containing these metals.

[0068] The shape of the substrate is not particularly limited, and may be flat or three-dimensional. Specific examples of the substrate include automobile bodies and parts thereof, such as passenger cars, trucks, motorcycles, and buses.

[0069] The metal substrate may have been subjected to a chemical conversion treatment using a phosphate-based chemical conversion treatment agent, a zirconium-based chemical conversion treatment agent, or the like, and may have been subjected to electrodeposition coating. The electrodeposition coating composition may be either a cationic type or an anionic type. A cationic electrodeposition coating composition can form a coating film with excellent corrosion resistance.

[0070] The metal substrate may have an electrodeposition coating and an intermediate coating disposed thereon. The intermediate coating is usually provided for the purpose of improving the adhesion and durability of the multi-layer coating. The intermediate coating composition may contain, for example, a film-forming resin, a curing agent, a color pigment, and an extender pigment. Examples of the film-forming resin and curing agent include those contained in the first coating composition.

[0071] [Manufacturing method for coated articles] The method for manufacturing a coated article according to the present disclosure comprises applying a first coating composition onto an object to be coated to form a first coating film, applying a second coating composition containing an optical interference pigment onto the first coating film to form a second coating film, and applying a clear coating composition onto the second coating film to form a clear coating film.

[0072] In one embodiment, the coated article is produced by sequentially applying a first coating composition and a second coating composition to a substrate, curing the applied compositions, and then applying and curing a clear coating composition. After applying the first coating composition, preheating may be performed before applying the second coating composition.

[0073] In another embodiment, a coated article is produced by successively applying a first coating composition, a second coating composition, and a clear coating composition wet-on-wet to a substrate, and then curing these coating compositions all at once. Preheating may be performed after applying the first coating composition and before applying the second coating composition, and after applying the second coating composition and before applying the clear coating composition.

[0074] Examples of coating methods include air spray coating, airless spray coating, electrostatic spray coating, multi-stage coating (preferably two-stage coating) using air electrostatic spray coating, and coating that combines air electrostatic spray coating with a rotary atomizer-type electrostatic coater.

[0075] Each coating composition is cured, for example, at a heating temperature of 80°C to 180°C (preferably 100°C to 160°C) for a heating time of 5 to 60 minutes (preferably 10 to 30 minutes).

[0076] (First paint composition) The first coating composition contains a pigment for adjusting brightness (typically a white pigment and a black pigment) and a film-forming resin. The first coating composition may be water-based or solvent-based. The water-based first coating composition may contain water as the main solvent, and optionally a water-soluble or water-miscible organic solvent. The solvent-based first coating composition may contain, for example, an ester solvent, an ether solvent, an alcohol solvent, a ketone solvent, an aliphatic hydrocarbon solvent, or an aromatic solvent as the main solvent. The first coating composition may be diluted with a solvent suitable for application before use. The first coating composition may be water-based. The main solvent accounts for 50% by mass or more of the total solvent.

[0077] White pigment The white pigment is not particularly limited. Examples of white pigments include titanium dioxide, zinc oxide, and silica. These may be used alone or in combination of two or more. Titanium dioxide may be used because of its high refractive index. Titanium dioxide may be of the rutile type or the anatase type. In particular, rutile type titanium dioxide is preferred from the viewpoint of weather resistance. The surface of titanium dioxide may be treated with an inorganic compound such as silica, zirconium, or aluminum.

[0078] The primary particle diameter of the white pigment is not particularly limited. From the viewpoint of hiding power, the primary particle diameter of the white pigment may be 100 nm or more and 500 nm or less, or 200 nm or more and 400 nm or less.

[0079] The amount of the white pigment to be blended is not particularly limited. C1 * 45 ≦15 20≦L1 * 45 ≦70 The components are blended to satisfy the following relationship.

[0080] Specifically, the amount of the white pigment may be 10% by mass or more and 50% by mass or less of the first coating film. The amount of the white pigment may be 20% by mass or more and 30% by mass or more of the first coating film. The amount of the white pigment may be 45% by mass or less and 40% by mass or less of the first coating film.

[0081] Black pigment The black pigment is not particularly limited. Examples of black pigments include carbon black; composite metal oxides such as iron chromium and bismuth manganese; perylene pigments; and azomethiazo pigments. These may be used alone or in combination of two or more. The black pigment may be carbon black.

[0082] The primary particle size of the black pigment is not particularly limited. From the viewpoint of hiding power, the primary particle size of the black pigment may be 20 nm or more and 70 nm or less, or 30 nm or more and 60 nm or less.

[0083] The amount of the black pigment to be blended is not particularly limited. C1 * 45 ≦15 20≦L1 * 45 ≦70 The components are blended to satisfy the following relationship.

[0084] Specifically, the blending amount of the black pigment may be 0.5% by mass or more and 5% by mass or less of the first coating film. The blending amount of the black pigment may be 1% by mass or more and 2% by mass or more of the first coating film. The blending amount of the black pigment may be 4% by mass or less and 3% by mass or less of the first coating film.

[0085] The blending ratio of the white pigment to the black pigment (white:black) may be, for example, 50:1 to 20:1 by mass, or 40:1 to 30:1 by mass.

[0086] 《Coating film forming resin》 Examples of the film-forming resin include acrylic resin, acrylic silicone resin, polyester resin, polyurethane resin, epoxy resin, fluororesin, and silicone resin. These may be used alone or in combination of two or more. Among these, acrylic resin is preferred.

[0087] In the aqueous first coating composition, these resins may be contained as an emulsion, may be contained as a dispersion, or may be contained in a state of being dissolved in a solvent.

[0088] For example, acrylic resin emulsions can be prepared by emulsion polymerization of α,β-ethylenically unsaturated monomers. Examples of α,β-ethylenically unsaturated monomers include (meth)acrylic acid esters, α,β-ethylenically unsaturated monomers having an acid group, and α,β-ethylenically unsaturated monomers having a hydroxyl group. The monomers can be used alone or in combination of two or more.

[0089] Examples of (meth)acrylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, phenyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, dicyclopentadienyl (meth)acrylate, and dihydrodicyclopentadienyl (meth)acrylate. (Meth)acrylic acid esters refer to acrylic acid esters and methacrylic acid esters.

[0090] Examples of α,β-ethylenically unsaturated monomers having an acid group include acrylic acid, methacrylic acid, crotonic acid, 2-acryloyloxyethyl phthalic acid, 2-acryloyloxyethyl succinic acid, ω-carboxy-polycaprolactone mono(meth)acrylate, isocrotonic acid, α-hydro-ω-((1-oxo-2-propenyl)oxy)poly(oxy(1-oxo-1,6-hexanediyl)), maleic acid, fumaric acid, itaconic acid, 3-vinylsalicylic acid, 3-vinylacetylsalicylic acid, 2-acrylamido-2-methylpropanesulfonic acid, p-hydroxystyrene, and 2,4-dihydroxy-4′-vinylbenzophenone.

[0091] Examples of α,β-ethylenically unsaturated monomers having a hydroxyl group include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, allyl alcohol, methallyl alcohol, and adducts of these with ε-caprolactone.

[0092] Other α,β-ethylenically unsaturated monomers may be used in combination. Examples of other α,β-ethylenically unsaturated monomers include polymerizable amide compounds, polymerizable aromatic compounds, polymerizable nitriles, polymerizable alkylene oxide compounds, polyfunctional vinyl compounds, polymerizable amine compounds, α-olefins, dienes, polymerizable carbonyl compounds, polymerizable alkoxysilyl compounds, and other polymerizable compounds.

[0093] The emulsion polymerization method is not particularly limited. For example, an emulsifier is dissolved in an aqueous medium containing water or, if necessary, an organic solvent such as an alcohol or an ether (e.g., dipropylene glycol methyl ether, propylene glycol methyl ether, etc.), and an α,β-ethylenically unsaturated monomer and a polymerization initiator are added dropwise under heating and stirring. The α,β-ethylenically unsaturated monomer may be previously emulsified with an emulsifier.

[0094] Polymerization initiators and emulsifiers commonly used by those skilled in the art can be used. If necessary, a chain transfer agent such as a mercaptan (e.g., lauryl mercaptan) or α-methylstyrene dimer may be used to adjust the molecular weight. The reaction temperature, reaction time, and other parameters can be appropriately selected within the ranges commonly used by those skilled in the art. The resulting acrylic resin emulsion is neutralized with a base, if necessary.

[0095] The acrylic resin (acrylic resin emulsion) obtained by emulsion polymerization may have a number average molecular weight of 3,000 or more. The acrylic resin may have a hydroxyl value (solid content hydroxyl value) of 20 mgKOH / g or more and 180 mgKOH / g or less. The acrylic resin may have an acid value (solid content acid value) of 1 mgKOH / g or more and 80 mgKOH / g or less.

[0096] The number average molecular weight is determined by the GPC method using polystyrene as the standard. The acid value and hydroxyl value of the film-forming resin are calculated from the monomer composition used in the preparation, based on JIS regulations.

[0097] The acrylic resin dispersion can be prepared, for example, by solution polymerizing the above-mentioned α,β-ethylenically unsaturated monomer and dispersing the resultant with a basic compound.

[0098] The water-soluble acrylic resin can be prepared, for example, by solution polymerizing the above-mentioned α,β-ethylenically unsaturated monomer and then solubilizing it in water using a basic compound.

[0099] The acrylic resin blended in the solvent-based first coating composition can be prepared, for example, by solution polymerization of an α,β-ethylenically unsaturated monomer. The acrylic resin has a number average molecular weight of, for example, 1,000 to 20,000. The acrylic resin may have an acid value (solid acid value) of 1 mgKOH / g to 80 mgKOH / g. The acrylic resin may have a hydroxyl value (solid hydroxyl value) of 101 mgKOH / g to 200 mgKOH / g.

[0100] Hardener The first coating composition may include a curing agent that reacts with the film-forming resin to form the first coating therewith.

[0101] Examples of curing agents include melamine resins, blocked isocyanate compounds, epoxy compounds, aziridine compounds, carbodiimide compounds, oxazoline compounds, and metal ions. These may be used alone or in combination of two or more. Among these, at least one of melamine resins and blocked isocyanate compounds may be used.

[0102] The melamine resin may be water-soluble or water-insoluble. The melamine resin has a structure in which hydrogen atoms or substituents (such as alkyl ether groups and methylol groups) are bonded to the periphery of a melamine nucleus (triazine nucleus) via three nitrogen atoms. The melamine resin is generally composed of a polynuclear compound in which multiple melamine nuclei are bonded to each other. The melamine resin may also be a mononuclear compound consisting of one melamine nucleus.

[0103] Commercially available melamine resins may be used. Examples of commercially available melamine resins include the Cymel series (trade name) manufactured by Allnex, specifically Cymel 202, Cymel 204, Cymel 211, Cymel 232, Cymel 235, Cymel 236, Cymel 238, Cymel 250, Cymel 251, Cymel 254, Cymel 266, Cymel 267, Cymel 272, Cymel 285, Cymel 301, Cymel 303, Cymel 325, Cymel 327, Cymel 350, Cymel 370, Cymel 701, Cymel 703, and Cymel 1141; and the U-Ban (trade name) series manufactured by Mitsui Chemicals, Inc. These may be used alone or in combination of two or more.

[0104] The blocked isocyanate compound can be prepared by adding a blocking agent having an active hydrogen to a polyisocyanate such as trimethylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, or isophorone diisocyanate.

[0105] The content of the curing agent may be 10% by mass or more and 80% by mass or less of the resin solid content contained in the first coating composition. The content of the curing agent may be 15% by mass or more. The content of the curing agent may be 60% by mass or less.

[0106] The first coating composition is prepared by kneading and dispersing the white pigment, black pigment, film-forming resin, curing agent, etc. using a disperser, homogenizer, kneader, etc. A pigment paste may be prepared in advance using pigments such as white pigment and black pigment and a pigment dispersant, and this may then be mixed with the film-forming resin, etc.

[0107] Other pigments The first coating composition (first coating film) may further contain pigments other than white pigments and black pigments. Examples of other pigments include chromatic pigments, extender pigments, anti-rust pigments, and glitter pigments (including optical interference pigments). The other pigments are blended in to a range that does not impair the properties and functions of the first coating film.

[0108] Additives The first coating composition may contain additives commonly used by those skilled in the art, such as surface conditioners, viscosity control agents, thickeners, antioxidants, ultraviolet inhibitors, and antifoaming agents.

[0109] (Second paint composition) The second coating composition comprises an optical interference pigment and a film-forming resin, and may further comprise a color pigment. The second coating composition may be water-based or solvent-based. The solvent contained in the second coating composition and the method for preparing the second coating composition are the same as those for the first coating composition.

[0110] 《Coating film forming resin》 Examples of the film-forming resin include those listed as being contained in the first coating composition. The film-forming resins contained in the first and second coating compositions may be the same or different. In addition, the second coating composition may contain the same components as the first coating composition.

[0111] Other pigments The second coating film may further contain pigments other than the optical interference pigments. Examples of other pigments include color pigments (including white pigments and black pigments), extender pigments, anti-rust pigments, and lustrous pigments other than the optical interference pigments. The other pigments are blended to the extent that they do not impair the properties and functions of the second coating film.

[0112] 《Organic compounds containing phosphate groups》 The second coating composition may further contain a phosphate group-containing organic compound, which facilitates improving the dispersibility of scaly pigments (for example, optical interference pigments).

[0113] The content of the phosphate group-containing compound may be 0.1% by mass or more and 15% by mass or less of the total solid content of the second coating composition. The content of the phosphate group-containing compound may be 1% by mass or more. The content of the phosphate group-containing compound may be 12% by mass or less.

[0114] The phosphate group-containing compound is not particularly limited as long as it has a phosphate group (-P(=O)(OR)2 (where each R is independently hydrogen or a hydrocarbon group)). Examples of the phosphate group-containing compound include at least one of an alkyl phosphate ester having an alkyl group with 4 to 30 carbon atoms and a phosphate group-containing polymer having a phosphate group value of 5 mgKOH / g or more and 300 mgKOH / g or less.

[0115] <Alkyl phosphate ester> The alkyl phosphate ester has an alkyl group having 4 to 30 carbon atoms. Examples of the alkyl phosphate ester include monoalkyl phosphate ester, dialkyl phosphate ester, and mixtures thereof. In the dialkyl phosphate ester, the two alkyl groups may be the same or different. The dialkyl phosphate ester preferably has the same two alkyl groups.

[0116] Examples of alkyl groups having 4 to 30 carbon atoms include butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, docosyl, tetracosyl, hexacosyl, and octacosyl. The alkyl group may be linear or branched.

[0117] Examples of alkyl phosphate esters include butyl acid phosphate (a mixture of monobutyl phosphate ester and dibutyl phosphate ester), 2-ethylhexyl acid phosphate (a mixture of mono-2-ethylhexyl phosphate ester and di-2-ethylhexyl phosphate ester), isodecyl acid phosphate (a mixture of monoisodecyl phosphate ester and diisodecyl phosphate ester), dilauryl acid phosphate, lauryl acid phosphate (a mixture of monolauryl phosphate ester and dilauryl phosphate ester), tridecyl acid phosphate (monotridecyl phosphate), Examples of suitable oleic acid phosphates include monostearyl acid phosphate, distearyl acid phosphate, stearyl acid phosphate (a mixture of monostearyl phosphate and distearyl phosphate), isostearyl acid phosphate (a mixture of monoisostearyl phosphate and diisostearyl phosphate), oleyl acid phosphate (a mixture of monooleyl phosphate and dioleyl phosphate), and behenyl acid phosphate (a mixture of monobehenyl phosphate and dibehenyl phosphate).

[0118] <Phosphate group-containing polymer> The phosphate group-containing polymer has a phosphate value of 5 mgKOH / g or more and 300 mgKOH / g or less. The phosphate group value of the phosphate group-containing polymer may be 10 mgKOH / g or more, or 50 mgKOH / g or more. The phosphate group value of the phosphate group-containing polymer may be 250 mgKOH / g or less, or 150 mgKOH / g or less.

[0119] The phosphate value is the number of milligrams of potassium hydroxide (KOH) required for neutralization, calculated based on the blend amount of the phosphate group-containing component, such as a phosphate ester, used in preparing the phosphate group-containing polymer.

[0120] The number average molecular weight of the phosphate group-containing polymer is, for example, 1,000 or more and 50,000 or less. The number average molecular weight of the phosphate group-containing polymer may be 3,000 or more, or 5,000 or more. The number average molecular weight of the phosphate group-containing polymer may be 30,000 or less, or 20,000 or less.

[0121] Examples of the phosphate group-containing polymer include acrylic resins, polyester resins, polyether resins, and epoxy resins, each having a phosphate group value of 5 mgKOH / g or more and 300 mgKOH / g or less. These may be used alone or in combination of two or more. Among these, phosphate group-containing acrylic resins are preferred. The phosphate group-containing acrylic resins can be obtained, for example, by polymerizing a phosphate group-containing α,β-ethylenically unsaturated monomer, or by copolymerizing this monomer with another α,β-ethylenically unsaturated monomer that does not contain a phosphate group.

[0122] Additives The second coating composition may contain additives commonly used by those skilled in the art, including, for example, those listed as additives contained in the first coating composition.

[0123] (Clear paint composition) The clear coating composition may be solvent-based, water-based, or powder-type. The clear coating composition may be solvent-based.

[0124] The clear coating composition may be, for example, an acid epoxy curing type containing a polyepoxide and a polycarboxylic acid, or a urethane curing type containing a hydroxyl group-containing resin and a polyisocyanate curing agent. The urethane curing type clear coating composition may be a two-component type.

[0125] The acid-epoxy curing clear coating composition contains, for example, an acid anhydride group-containing acrylic resin (a), a carboxyl group-containing polyester resin (b), and an acrylic resin (c) having a hydroxyl group and an epoxy group. From the viewpoint of storage stability, the acid anhydride group of the acid anhydride group-containing acrylic resin (a) may be half-esterified with a low-molecular-weight alcohol, etc. The carboxyl group-containing polyester resin (b) may further contain a hydroxyl group.

[0126] The resins (a) to (c) are blended so that, for example, the molar ratio of the carboxyl groups contained in the acrylic resin (a) and the polyester resin (b) to the epoxy groups contained in the acrylic resin (c) is 1 / 1.4 to 1 / 0.6 (preferably 1 / 1.2 to 1 / 0.8), and the molar ratio of the carboxyl groups derived from the acid anhydride groups contained in the acrylic resin (a) to the hydroxyl groups contained in the polyester resin (b) and the acrylic resin (c) is 1 / 2.0 to 1 / 0.5 (preferably 1 / 1.5 to 1 / 0.7).

[0127] The urethane curing clear coating composition contains, for example, a hydroxyl group-containing resin and a polyisocyanate curing agent. Examples of the polyisocyanate curing agent include aliphatic isocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (HDI), and trimethylhexamethylene diisocyanate; aliphatic cyclic isocyanates such as 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, and 1,2-cyclohexane diisocyanate; aromatic isocyanates such as xylylene diisocyanate (XDI), 2,4-tolylene diisocyanate (TDI), and 2,6-tolylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate (IPDI) and norbornane diisocyanate methyl; and multimers and mixtures thereof, such as biuret and nurate forms.

[0128] The hydroxyl value of the hydroxyl-containing resin is, for example, 20 mgKOH / g or more and 200 mgKOH / g or less. The hydroxyl value may be 30 mgKOH / g or more. The hydroxyl value may be 180 mgKOH / g or less. The weight average molecular weight of the hydroxyl-containing resin is, for example, 1,000 or more and 20,000 or less. The weight average molecular weight may be 2,000 or more. The weight average molecular weight may be 15,000 or less. The acid value of the hydroxyl-containing resin is, for example, 2 mgKOH / g or more and 30 mgKOH / g or less. The acid value may be 3 mgKOH / g or more. The acid value may be 25 mgKOH / g or less.

[0129] The hydroxyl group-containing resin and the polyisocyanate curing agent are blended, for example, so that the equivalent ratio (NCO / OH) of the isocyanate group (NCO) to the hydroxyl group (OH) is 0.5 or more and 1.7 or less. The equivalent ratio may be 0.7 or more. The equivalent ratio may be 1.5 or less.

[0130] Alternatively, an acrylic melamine curing type clear coating composition may be used. [Example]

[0131] The present invention will be described in more detail with reference to the following examples, but is not limited thereto. In the examples, "parts" and "%" are by weight unless otherwise specified.

[0132] The number average molecular weight was measured using a GPC apparatus with the trade name "HLC8220GPC" (manufactured by Tosoh Corporation) and four columns with the trade names "Shodex F-606M" and "Shodex KF-603" (both manufactured by Showa Denko K.K.), under the following conditions: mobile phase: tetrahydrofuran, measurement temperature: 40°C, flow rate: 0.6 cc / min, and detector: RI.

[0133] The phosphate value is the amount of potassium hydroxide (KOH) required for neutralization, calculated based on the amount of phosphate-containing components, such as phosphate esters, used in preparing the phosphate-containing polymer. The acid value and hydroxyl value were calculated from the monomer composition used in the preparation, in accordance with JIS regulations.

[0134] [Production Example 1] Production of acrylic resin emulsion A reaction vessel was charged with 633 parts of deionized water and heated to 80°C while mixing and stirring in a nitrogen stream. Separately, a first-stage monomer mixture was prepared by mixing 75.65 parts of styrene (ST), 178.96 parts of methyl methacrylate (MMA), 75.94 parts of n-butyl acrylate (BA), 64.45 parts of 2-ethylhexyl acrylate (2-EHA), and 105.0 parts of hydroxyethyl methacrylate (HEMA). This monomer mixture was then mixed with 25.0 parts of Aqualon HS-10 (polyoxyethylene alkylpropenylphenyl ether sulfate, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), 25.0 parts of Adeka Reasoap NE-20 (α-[1-[(allyloxy)methyl]-2-(nonylphenoxy)ethyl]-ω-hydroxyoxyethylene, manufactured by Asahi Denka Co., Ltd.), and 400 parts of deionized water to prepare a monomer emulsion. Separately, an initiator solution consisting of 1.2 parts ammonium persulfate and 500 parts deionized water was prepared. The monomer emulsion and the initiator solution were added dropwise to the reaction vessel over 1.5 hours. After the addition was completed, the mixture was aged at the same temperature for 1 hour.

[0135] A second-stage monomer mixture was prepared by mixing 53.65 parts of styrene (ST), 178.96 parts of methyl methacrylate (MMA), 75.94 parts of n-butyl acrylate (BA), 64.45 parts of 2-ethylhexyl acrylate (2-EHA), 105.0 parts of hydroxyethyl methacrylate (HEMA), and 22 parts of acrylic acid. This monomer mixture was then mixed with 10 parts of Aqualon HS-10 and 250 parts of deionized water to prepare a monomer emulsion. Separately, an initiator solution consisting of 3.0 parts of ammonium persulfate and 500 parts of deionized water was prepared. The monomer emulsion and initiator solution were added dropwise to the reaction vessel over 1.5 hours. After the addition was complete, the mixture was aged at the same temperature for 2 hours.

[0136] The reaction mixture was then cooled to 40°C and filtered through a 400-mesh filter. Finally, 100 parts of deionized water and 1.6 parts of dimethylaminoethanol were added to the reaction mixture to adjust the pH to 6.5. In this way, an acrylic resin emulsion was obtained with an average particle size of 150 nm, a solids concentration of 35%, a solids acid value of 20 mgKOH / g, and a hydroxyl value of 100 mgKOH / g.

[0137] [Production Example 2] Production of a phosphate group-containing polymer A 1-liter reaction vessel equipped with a stirrer, temperature controller, and condenser was charged with 40 parts of ethoxypropanol. Separately, a solution was prepared by dissolving 20 parts of Hosmer PP (acid phosphooxyhexa(oxypropylene) monomethacrylate, manufactured by Unichemical Co.) in 20 parts of ethoxypropanol. A monomer solution was prepared by mixing 40 parts of this solution with 4 parts of styrene, 35.96 parts of n-butyl acrylate, 18.45 parts of ethylhexyl methacrylate, 13.92 parts of 2-hydroxyethyl methacrylate, 7.67 parts of methacrylic acid, and 1.7 parts of azobisisobutyronitrile. 121.7 parts of the monomer solution was added dropwise to the reaction vessel at 120°C over 3 hours. Stirring was continued for another hour to obtain a phosphate group-containing polymer. The phosphate group-containing polymer thus obtained had an acid value of 105 mgKOH / g, a phosphate group value of 55 mgKOH / g, a hydroxyl group value of 60 mgKOH / g, a number average molecular weight of 6,000, and a solids concentration of 63%.

[0138] [Production Example 3] Production of water-soluble acrylic resin 23.89 parts of tripropylene 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 while stirring in a nitrogen stream. Next, a monomer mixture containing 13.1 parts of methyl methacrylate, 68.4 parts of ethyl acrylate, 11.6 parts of 2-hydroxyethyl methacrylate, and 6.9 parts of methacrylic acid was prepared. An initiator solution consisting of 100 parts of this monomer mixture, 10.0 parts of tripropylene glycol methyl ether, and 1 part of tert-butyl peroxy 2-ethylhexanoate was added dropwise to the reaction vessel in parallel over 3 hours. After the completion of the dropwise addition, the mixture was aged at the same temperature for 0.5 hours.

[0139] Further, an initiator solution consisting of 5.0 parts of tripropylene glycol methyl ether and 0.3 parts of tertiary butyl peroxy 2-ethylhexanoate was added dropwise to the reaction vessel over 0.5 hours. After the addition was completed, the mixture was aged at the same temperature for 2 hours.

[0140] After 16.1 parts of the solvent were distilled off under reduced pressure (70 torr) at 110°C using a solvent remover, 204 parts of deionized water and 7.1 parts of dimethylaminoethanol were added to obtain a water-soluble acrylic resin solution. The resulting water-soluble acrylic resin solution had a solids concentration of 30%, a solids acid value of 40 mg KOH / g, a hydroxyl value of 50 mg KOH / g, and a viscosity of 140 poise (E-type viscometer, 1 rpm / 25°C).

[0141] [Example 1] (1) Preparation of first coating composition (1-1) Preparation of Color Pigment Dispersion A1 10 parts of the water-soluble acrylic resin solution of Production Example 3, 48 parts of a white pigment (titanium dioxide), 0.3 parts of a black pigment (carbon black), 2.5 parts of a pigment dispersant (trade name: DISPEX ULTRA PA 4550AN), 40 parts of ion-exchanged water, and 0.5 parts of an antifoaming agent (trade name: BYK-011) were mixed with a stirrer. Subsequently, this mixture was dispersed using a disperser filled with 0.05 mm zirconia beads at a volume filling rate of 70%, to obtain color pigment dispersion A1.

[0142] (1-2) Preparation of first coating composition 90 parts of the acrylic resin emulsion of Production Example 1, 2.0 parts of dimethylaminoethanol, 28.4 parts of melamine resin (trade name: Cymel 370N, mixed alkylated melamine resin, manufactured by Allnex, solids content 90%), 100 parts of color pigment dispersion A1, 50 parts of butyl cellosolve, 5.5 parts (3 parts in terms of solids) of surfactant (trade name: Noigen EA-207D, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., number average molecular weight 4200, solids content 55%), and 3 parts of linoleic acid (manufactured by Kishida Chemical Co., Ltd.) were uniformly dispersed. Dimethylaminoethanol was added to this dispersion to adjust the pH to 8.1, and the mixture was diluted with deionized water to obtain an aqueous first coating composition with a total solids concentration of 25%.

[0143] (2) Preparation of second coating composition 100 parts of the acrylic resin emulsion of Production Example 1, 1.4 parts of dimethylaminoethanol, 28.4 parts of melamine resin (trade name: Cymel 370N), 1.7 parts of optical interference pigment A (trade name: Xirallic T60-23, manufactured by MERCK), 1.7 parts of optical interference pigment C (trade name: Xirallic T60-25, manufactured by MERCK), 5 parts of the phosphate group-containing polymer of Production Example 2, 0.4 parts of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of surfactant (trade name: Noigen EA-207D) (3 parts in terms of solids), and 3 parts of linoleic acid (manufactured by Kishida Chemical Co., Ltd.) were uniformly dispersed. Dimethylaminoethanol was added to this dispersion to adjust the pH to 8.1, and the mixture was diluted with deionized water to prepare an aqueous second coating composition with a total solids concentration of 25%.

[0144] (3) Preparation of clear coating composition An acid-epoxy curing clear paint (trade name: Macflow-O-1810 Clear, manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was prepared as a clear paint composition.

[0145] (4) Formation of multi-layer coating A zinc phosphate-treated, 0.8 mm thick, 30 cm long, and 40 cm wide dull steel plate was electrodeposited with the cationic electrodeposition coating composition "Power Top U-50" (manufactured by Nippon Paint Automotive Coatings) to a dry film thickness of 20 μm and baked at 160°C for 30 minutes. The resulting coated plate was then air-sprayed with the intermediate coating composition "OP-30P Middle Gray" (manufactured by Nippon Paint Automotive Coatings, polyester-melamine paint, pre-diluted to 25 seconds (measured at 20°C using a No. 4 Ford cup)) using an Anest Iwata W-101-132G air spray gun to a dry film thickness of 35 μm, followed by heating at 140°C for 30 minutes. This resulted in a coated substrate with both an electrodeposition coating and an intermediate coating.

[0146] The first coating composition was air-spray coated onto the substrate at a room temperature of 23°C and a humidity of 68% to a dry film thickness of 10 μm. After setting for 1.5 minutes, the second coating composition was air-spray coated wet-on-wet at a room temperature of 23°C and a humidity of 68% to a dry film thickness of 10 μm. After setting for 3 minutes, the substrate was preheated at 80°C for 3 minutes. The coated plate was allowed to cool to room temperature, and the clear coating composition was air-spray coated to a dry film thickness of 35 μm and allowed to set for 7 minutes. Finally, the coated plate was heated in a dryer at 140°C for 30 minutes to obtain a coated article with a multi-layer coating film.

[0147] [Example 2] (1) Preparation of first coating composition A color pigment dispersion A2 was prepared in the same manner as in Example 1, except that 49 parts of a white pigment (titanium dioxide) and 0.2 parts of a black pigment (carbon black) were mixed. A first coating composition was prepared in the same manner as in Example 1, except that the color pigment dispersion A2 was used instead of the color pigment dispersion A1.

[0148] (2) Preparation of second coating composition The second coating composition was prepared in the same manner as in Example 1, except that 8.5 parts of optical interference pigment F (product name: BXC-SO, manufactured by Nippon Koken Co., Ltd.) was used instead of optical interference pigment A, and the amount of optical interference pigment C was changed to 10.2 parts.

[0149] A multi-layer coating film and a coated article were obtained in the same manner as in Example 1, except that the above first coating composition and second coating composition were used.

[0150] [Example 3] (2) Preparation of second coating composition The second coating composition was prepared in the same manner as in Example 1, except that instead of the optical interference pigments A and C, 8.5 parts of optical interference pigment B (trade name: Xirallic T60-20, manufactured by MERCK) and 8.5 parts of another luminescent pigment a (trade name: GT1020RSJ3, manufactured by Nippon Sheet Glass Co., Ltd.) were used.

[0151] A multi-layer coating film and a coated article were obtained in the same manner as in Example 1, except that the above second coating composition was used.

[0152] [Example 4] (1) Preparation of first coating composition A color pigment dispersion A4 was prepared in the same manner as in Example 1, except that 35 parts of a white pigment (titanium dioxide), 1.3 parts of a black pigment (carbon black), 1.5 parts of a color pigment 3 (quinacridone red, trade name: Rubicron 400RG, manufactured by DIC Corporation), and 0.8 parts of a color pigment 4 (cyanine blue, trade name: Cyanine Blue G-314R, manufactured by Sanyo Dish Co., Ltd.) were mixed. A first coating composition was prepared in the same manner as in Example 1, except that color pigment dispersion A4 was used instead of color pigment dispersion A1.

[0153] (2) Preparation of second coating composition (2-1) Preparation of Color Pigment Dispersion B1 10 parts of the water-soluble acrylic resin solution of Production Example 3, 35 parts of color pigment 1 (titanium dioxide), 2.5 parts of color pigment 2 (carbon black), 0.3 parts of color pigment 3, 0.3 parts of color pigment 4, 3 parts of a pigment dispersant (trade name: DISPEX ULTRA PA 4550AN), 47.6 parts of ion-exchanged water, and 1 part of an antifoaming agent (trade name: BYK-011) were mixed with a stirrer. Subsequently, this mixture was dispersed using a disperser filled with 0.05 mm zirconia beads at a volume filling rate of 70% to obtain color pigment dispersion B1.

[0154] (2-2) Preparation of second coating composition 100 parts of the acrylic resin emulsion of Production Example 1, 1.4 parts of dimethylaminoethanol, 28.4 parts of melamine resin (trade name: Cymel 370N), 1.7 parts of optical interference pigment A, 2.3 parts of colored pigment dispersion B1, 5 parts of the phosphate group-containing polymer of Production Example 2, 0.4 parts of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of surfactant (trade name: Noigen EA-207D) (3 parts in terms of solids), and 3 parts of linoleic acid (manufactured by Kishida Chemical Co., Ltd.) were uniformly dispersed. Dimethylaminoethanol was added to this dispersion to adjust the pH to 8.1, and the mixture was diluted with deionized water to prepare an aqueous second coating composition with a total solids concentration of 25%.

[0155] A multi-layer coating film and a coated article were obtained in the same manner as in Example 1, except that the above first coating composition and second coating composition were used.

[0156] [Example 5] (1) Preparation of first coating composition 39 parts of white pigment (titanium dioxide), 1.9 parts of black pigment (carbon black), 0.2 parts of color pigment 3, 0.4 parts of color pigment 4, and 1.2 parts of luster pigment b (trade name: MH-8801, manufactured by Asahi Chemical Industry Co., Ltd., flaky aluminum pigment paste, active ingredient 63.7%) were mixed relative to 100 parts of the solids content of the first coating composition. Except for this, a color pigment dispersion A5 was prepared in the same manner as in Example 1. A first coating composition was prepared in the same manner as in Example 1, except that the color pigment dispersion A5 was used instead of the color pigment dispersion A1.

[0157] (2) Preparation of second coating composition (2-1) Preparation of Color Pigment Dispersion B2 10 parts of the water-soluble acrylic resin solution of Production Example 2, 6 parts of color pigment 2 (carbon black), 2.7 parts of color pigment 3, 2.2 parts of color pigment 4, 5 parts of a pigment dispersant (trade name: DISPEX ULTRA PA 4550AN), 69.4 parts of ion-exchanged water, and 1 part of an antifoaming agent (trade name: BYK-011) were mixed with a stirrer. Subsequently, this mixture was dispersed using a disperser filled with 0.05 mm zirconia beads at a volume filling rate of 70% to obtain color pigment dispersion B2.

[0158] (2-2) Preparation of second coating composition 100 parts of the acrylic resin emulsion of Production Example 1, 1.4 parts of dimethylaminoethanol, 28.4 parts of melamine resin (trade name: Cymel 370N), 8.5 parts of optical interference pigment F, another lustrous pigment B (scale-shaped aluminum pigment paste, trade name: MH-8801, manufactured by Asahi Chemical Industry Co., Ltd., active ingredient 63.7%) in an amount of 0.2 parts per 100 parts of the solids of the second coating composition, 1.6 parts of colored pigment dispersion B2, 5 parts of the phosphate group-containing polymer of Production Example 2, 0.4 parts of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of surfactant (trade name: Noigen EA-207D) (3 parts in terms of solids), and 3 parts of linoleic acid (manufactured by Kishida Chemical Co., Ltd.) were uniformly dispersed. Dimethylaminoethanol was added to this dispersion to adjust the pH to 8.1, and the mixture was diluted with deionized water to prepare an aqueous second coating composition with a total solids concentration of 25%.

[0159] A multi-layer coating film and a coated article were obtained in the same manner as in Example 1, except that the above first coating composition and second coating composition were used.

[0160] [Comparative Example 1] (1) Preparation of first coating composition A color pigment dispersion a1 was prepared in the same manner as in Example 1, except that 7 parts of a white pigment (titanium dioxide) and 9.5 parts of the luster pigment b were mixed relative to 100 parts of the solid content of the first coating composition. A first coating composition was prepared in the same manner as in Example 1, except that the color pigment dispersion a1 was used instead of the color pigment dispersion A1.

[0161] (2) Preparation of second coating composition The second coating composition was prepared in the same manner as in Example 1, except that 5.1 parts of optical interference pigment F was used instead of optical interference pigment A, and the amount of optical interference pigment C was changed to 6.8 parts.

[0162] A multi-layer coating film and a coated article were obtained in the same manner as in Example 1, except that the above first coating composition and second coating composition were used.

[0163] Comparative Example 2 (1) Preparation of first coating composition A color pigment dispersion a2 was prepared in the same manner as in Example 1, except that 33 parts of a white pigment (titanium dioxide), 0.9 parts of a black pigment (carbon black), 1 part of color pigment 3, and 2.5 parts of color pigment 4 were mixed. A first coating composition was prepared in the same manner as in Example 1, except that color pigment dispersion a2 was used instead of color pigment dispersion A1.

[0164] A multi-layer coating film and a coated article were obtained in the same manner as in Comparative Example 1, except that the above first coating composition was used.

[0165] Comparative Example 3 (1) Preparation of first coating composition A color pigment dispersion a3 was prepared in the same manner as in Example 1, except that 49 parts of a white pigment (titanium dioxide) and 0.1 parts of a black pigment (carbon black) were mixed. A first coating composition was prepared in the same manner as in Example 1, except that the color pigment dispersion a3 was used instead of the color pigment dispersion A1.

[0166] A multi-layer coating film and a coated article were obtained in the same manner as in Comparative Example 1, except that the above first coating composition was used.

[0167] Comparative Example 4 (1) Preparation of first coating composition A color pigment dispersion a4 was prepared in the same manner as in Example 1, except that 0.7 parts of a white pigment (titanium dioxide), 7 parts of a black pigment (carbon black), and 5.5 parts of a color pigment 4 were mixed. A first coating composition was prepared in the same manner as in Example 1, except that the color pigment dispersion a4 was used instead of the color pigment dispersion A1.

[0168] A multi-layer coating film and a coated article were obtained in the same manner as in Comparative Example 1, except that the above first coating composition was used.

[0169] Comparative Example 5 (1) Preparation of first coating composition A color pigment dispersion a5 was prepared in the same manner as in Example 1, except that 49 parts of a white pigment (titanium dioxide) and 0.2 parts of a black pigment (carbon black) were mixed. A first coating composition was prepared in the same manner as in Example 1, except that the color pigment dispersion a5 was used instead of the color pigment dispersion A1.

[0170] (2) Preparation of second coating composition A second coating composition was prepared in the same manner as in Example 1, except that 8.5 parts of optical interference pigment E (trade name: Xirallic T60-10, manufactured by MERCK) was used instead of optical interference pigments A and C.

[0171] A multi-layer coating film and a coated article were obtained in the same manner as in Example 1, except that the above first coating composition and second coating composition were used.

[0172] Comparative Example 6 (2) Preparation of second coating composition (2-1) Preparation of color pigment dispersion b1 10 parts of the water-soluble acrylic resin solution of Production Example 2, 5.8 parts of color pigment 2, 6.9 parts of color pigment 4, 0.2 parts of color pigment 5 (dioxazine violet, trade name: Hostaperm Violet RL, manufactured by Clariant), 7 parts of a pigment dispersant (trade name: DISPEX ULTRA PA 4550AN), 85 parts of ion-exchanged water, and 1.5 parts of an antifoaming agent (trade name: BYK-011) were mixed with a stirrer. Subsequently, this mixture was dispersed using a disperser filled with 0.05 mm zirconia beads at a volume filling rate of 70% to obtain color pigment dispersion b1.

[0173] (2-2) Preparation of second coating composition 100 parts of the acrylic resin emulsion of Production Example 1, 1.4 parts of dimethylaminoethanol, 28.4 parts of melamine resin (trade name: Cymel 370N), 0.5 parts of optical interference pigment A, 1.2 parts of optical interference pigment D (trade name: Xirallic T60-22, manufactured by MERCK), 0.5 parts of optical interference pigment E, 0.7 parts of optical interference pigment G (trade name: VXC-SO, manufactured by Nihon Koken Co., Ltd.), 60.7 parts of colored pigment dispersion b1, 5 parts of the phosphate group-containing polymer of Production Example 2, 0.4 parts of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of a surfactant (trade name: Noigen EA-207D) (3 parts in terms of solids content), and 3 parts of linoleic acid (manufactured by Kishida Chemical Co., Ltd.) were uniformly dispersed. Dimethylaminoethanol was added to this dispersion to adjust the pH to 8.1, and the dispersion was diluted with deionized water to prepare a water-based second coating composition with a total solids concentration of 15%.

[0174] A multi-layer coating film and a coated article were obtained in the same manner as in Comparative Example 5, except that the above second coating composition was used.

[0175] Comparative Example 7 (2) Preparation of second coating composition (2-1) Preparation of color pigment dispersion b2 10 parts of the water-soluble acrylic resin solution of Production Example 2, 29.4 parts of color pigment 1, 0.7 parts of color pigment 2, 1.9 parts of color pigment 4, 2.3 parts of color pigment 5, 3 parts of a pigment dispersant (trade name: DISPEX ULTRA PA 4550AN), 49.2 parts of ion-exchanged water, and 0.5 parts of an antifoaming agent (trade name: BYK-011) were mixed with a stirrer. Subsequently, this mixture was dispersed using a disperser filled with 0.05 mm zirconia beads at a volume filling rate of 70% to obtain color pigment dispersion b2.

[0176] (2-2) Preparation of second coating composition 100 parts of the acrylic resin emulsion of Production Example 1, 1.4 parts of dimethylaminoethanol, 28.4 parts of melamine resin (product name: Cymel 370N), 4.3 parts of optical interference pigment A, 4.3 parts of optical interference pigment F, 5.1 parts of other brilliant pigment b, 13.5 parts of colored pigment dispersion b2, 5 parts of the phosphate group-containing polymer of Production Example 2, 0.4 parts of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of surfactant (product name: Noigen EA-207D) (3 parts in terms of solids), and 3 parts of linoleic acid (manufactured by Kishida Chemical Co., Ltd.) were uniformly dispersed. Dimethylaminoethanol was added to this dispersion to adjust the pH to 8.1, and the mixture was diluted with deionized water to prepare an aqueous second coating composition with a total solids concentration of 25%.

[0177] A multi-layer (two-layer) coating film and a coated article were obtained in the same manner as in Example 1, except that the second coating composition was used and the first coating composition was not used.

[0178] [evaluation] The multi-layer coating films, the single first coating film, and the single second coating film obtained in the Examples and Comparative Examples were evaluated as follows. The evaluation results are shown in the table below.

[0179] In the table, the mass (%) of the pigment contained in the second coating film is the proportion when the second coating film (solid content of the second coating composition) is taken as 100 mass %.

[0180] (Preparation of a single first coating film) The first coating composition was spray-coated onto a substrate obtained in the same manner as in Example 1 so that the dry coating film would be 15 μm thick, and then the coating was cured by heating at 140° C. for 20 minutes. This resulted in a cured coating film of the first coating composition (single first coating film) applied to the substrate.

[0181] (Preparation of a separate second coating) The second coating composition was spray-coated onto a polypropylene plate to a dry film thickness of 15 μm, and then heat-cured for 20 minutes at 140° C. The coating was then peeled off from the polypropylene plate to obtain a film-like second coating film (single second coating film).

[0182] (Preparation of test coating film) The substrate was an approximately 174mm x 144mm piece of art paper with white and black areas, coated with a solvent-resistant transparent paint, and the diffuse reflectance at 45 degrees and 0 degrees was 80±1 for the white areas and 2 or less for the black areas.

[0183] The second coating composition was spray-coated onto the substrate to a dry film thickness of 15 μm, and then heat-cured for 20 minutes at 140° C. This yielded a cured coating film (test coating film) of the second coating composition applied to the black substrate.

[0184] (1) Lightness and saturation The lightness and chroma of the single first coating, the test coating, or the multi-layer coating were measured using a spectrophotometer (BYK Gardner, BYK-mac i).

[0185] (2) Average light transmittance The light transmittance of the second coating film alone was measured using a spectrophotometer (Hitachi, product name: U-4100) in the range of 400 to 700 nm in wavelength scan mode at a scan speed of 60 nm / min and a sampling interval of 2 nm. The average light transmittance was obtained by averaging the light transmittance every 10 nm.

[0186] (3) Solid feel The multi-layer coating film was viewed from angles equivalent to a light receiving angle of 45° (face area) and 110° (shade area) and evaluated based on the following criteria. If no graininess is felt, it can be evaluated as having a solid feel. If it is rated A, it can be said to have the desired design.

[0187] Evaluation criteria A: The granular feel of the glitter pigment is only sparse in the face area, and is barely noticeable in the shade area. B: The face area has a grainy feel overall, but the shade area has only a sparse grainy feel. C: There is a sense of graininess overall in both the face area and the shade area.

[0188] (4) Gray Multi-layer coating saturation (cm) * 45 and lightness Lm * 45 The evaluation was based on the following criteria: A rating indicates a grayish appearance.

[0189] Evaluation criteria A:Cm * 45 ≦10 and 30≦Lm * 45 Meets ≦65 B:10 <Cm * 45 ≦12 and 27≦Lm * 45 ≦68 or Cm * 45 ≦12 and 27≦Lm * 45 <30 or Cm * 45 ≦12 and 65 <Lm * 45 Meets ≦68 C:Cm * 45 >12 or Lm * 45 <27 or Lm * 45 >Meet 68

[0190] (5) Color Multi-layer coating saturation (cm) * 15 The results were evaluated based on the following criteria: A rating indicates that the color can be perceived.

[0191] Evaluation criteria A:Cm * 15 >10 B:7 <Cm * 15 Satisfies ≦10 C:Cm * 15 ≦7

[0192] [Table 1]

[0193] All of the multilayer coating films of the examples were visually recognized as a solid gray coating film in the face area, while the highlight area had a chromatic color, giving the coating film a unique design. Comparative Example 1 is an example of a metallic coating film in which the first coating film has a high flip-flop value. The multi-layer coating film of Comparative Example 1 did not have a chromatic color in the highlight area, and also did not have a solid feel. Comparative Example 2 is an example in which the first coating film has high saturation. The multi-layer coating film of Comparative Example 2 lacked a grayish appearance and did not have the design intended by the present disclosure. Comparative Examples 3 and 4 are examples in which the brightness of the first coating film is outside the range of the present disclosure. These multi-layer coating films lacked a grayish appearance and did not have the design intended by the present disclosure. Comparative Example 5 is an example in which the chroma of the multilayer coating film is outside the range of the present disclosure. In the multilayer coating film of Comparative Example 5, no chromatic color was perceived in the highlight area. Comparative Example 6 is an example in which the average light transmittance of the second coating film is low. In the multi-layer coating film of Comparative Example 6, the transparency of the second coating film was low, so the grayish appearance of the first coating film could not be recognized, and there was no solid appearance. Comparative Example 7 is an example in which a single coating film contains pigments for adjusting brightness (white pigment and black pigment) and a scaly pigment. The coating film of Comparative Example 7 did not have a solid feel in the face region.

[0194] The present disclosure includes the following aspects. [1] A multi-layer coating film comprising a first coating film, a second coating film disposed on the first coating film, and a clear coating film disposed on the second coating film, the second coating film contains a flaky pigment coated with a metal oxide; Incident light I1 incident at an angle of 45 degrees to the surface of the first coating film 45 The reflected light R1 is received at an angle of 45 degrees to the specular reflection light. 45 L based on the spectral reflectance of * C* Chroma C1 in the h color system * 45 and lightness L1 * 45 but, C1 * 45 ≦15 20≦L1 * 45 ≦70 Fulfilling the relationship, The incident light I1 45 The reflected light R1 is received at an angle of 15 degrees to the specular reflection light. 15 L based on the spectral reflectance of * C * Lightness L1 in the h color system * 15 and the incident light I1 45 The reflected light R1 is received at an angle of 110 degrees to the specular reflection light. 110 L based on the spectral reflectance of * C * Lightness L1 in the h color system * 110 But, L1 * 15 -L1 * 110 ≦15 Fulfilling the relationship, The second coating film has an average light transmittance of 50% or more in the wavelength range of 400 nm to 700 nm, Incident light Im incident on the surface of the multilayer coating film at an angle of 45 degrees 45 The reflected light Rm is received at an angle of 15 degrees to the specular reflection light. 15 L based on the spectral reflectance of * C * Chroma Cm in the h color system * 15 and the incident light Im 45 The reflected light Rm is received at an angle of 45 degrees to the specular reflection light. 45 L based on the spectral reflectance of * C * Chroma Cm in the h color system * 45 But, Cm * 15 >10 Cm* 15 -Cm * 45 >5 A multi-layer coating that satisfies the above relationship. [2] The second coating composition used to form the second coating film was applied to a black substrate, and incident light I2 was incident at an angle of 45 degrees to the surface of the test coating film obtained. 45 The reflected light R2 is received at an angle of 15 degrees to the specular reflection light. 15 L based on the spectral reflectance of * C * Chroma C2 in the h color system * 15 but, C2 * 15 ≧5 The multi-layer coating film of [1] above satisfies the relationship. [3] The multi-layer coating film of [1] or [2] above, wherein the content of the scale-like pigment is 0.5% by mass or more and 20% by mass or less of the second coating film. [4] the second coating further comprises a color pigment; The multi-layer coating film of any one of the above [1] to [3], wherein the content of the color pigment is 0.05% by mass or more and 1.5% by mass or less of the second coating film. [5] The multi-layer coating film according to [4] above, wherein the mass ratio of the scaly pigment to the color pigment is 2 or more and 400 or less. [6] The object to be coated a multilayer coating film according to any one of [1] to [5] above disposed on the substrate; and [7] Applying a first coating composition to an object to be coated to form a first coating film; Applying a second coating composition containing a scaly pigment coated with a metal oxide on the first coating film to form a second coating film; A method for producing a coated article having a multi-layer coating film, comprising: applying a clear coating composition on the second coating film to form a clear coating film; Incident light I1 incident at an angle of 45 degrees to the surface of the first coating film45 The reflected light R1 is received at an angle of 45 degrees to the specular reflection light. 45 L based on the spectral reflectance of * C * Chroma C1 in the h color system * 45 and lightness L1 * 45 but, C1 * 45 ≦15 20≦L1 * 45 ≦70 Fulfilling the relationship, The incident light I1 45 The reflected light R1 is received at an angle of 15 degrees to the specular reflection light. 15 L based on the spectral reflectance of * C * Lightness L1 in the h color system * 15 and the incident light I1 45 The reflected light R1 is received at an angle of 110 degrees to the specular reflection light. 110 L based on the spectral reflectance of * C * Lightness L1 in the h color system * 110 But, L1 * 15 -L1 * 110 ≦15 Fulfilling the relationship, the second coating film has an average light transmittance of 50% or more in the wavelength range of 400 nm to 700 nm; Incident light Im incident on the surface of the multilayer coating film at an angle of 45 degrees 45 The reflected light Rm is received at an angle of 15 degrees to the specular reflection light. 15 L based on the spectral reflectance of * C * Chroma Cm in the h color system * 15 and the incident light Im 45 The reflected light Rm is received at an angle of 45 degrees to the specular reflection light. 45 L based on the spectral reflectance of * C * Chroma Cm in the h color system *45 But, Cm * 15 >10 Cm * 15 -Cm * 45 >5 A method for manufacturing a coated article that satisfies the above relationship. [Industrial Applicability]

[0195] The multilayer coating film of the present disclosure exhibits a subdued gray color in the face area while exhibiting a chromatic color in the highlight area, thereby enabling new designs to be imparted to a variety of coated objects.

Claims

1. A multi-layer coating film comprising a first coating film, a second coating film disposed on the first coating film, and a clear coating film disposed on the second coating film, the second coating film is coated with a metal oxide, has optical coherence, and contains a chromatic scale-like pigment; the content of the scale-like pigment is 0.5% by mass or more and 20% by mass or less of the second coating film, the second coating film does not contain a color pigment or contains a color pigment in an amount of 1.0% by mass or less of the second coating film; Incident light I1 incident at an angle of 45 degrees to the surface of the first coating film ４５ The reflected light R1 is received at an angle of 45 degrees to the specular reflection light. ４５ L based on the spectral reflectance of ＊ C ＊ Chroma C1 in the h color system ＊ ４５ and lightness L1 ＊ ４５ but, C1 ＊ ４５ ≦15 20≦L1 ＊ ４５ ≦70 Fulfilling the relationship, The incident light I1 ４５ The reflected light R1 is received at an angle of 15 degrees with respect to the specular reflection light. １５ L based on the spectral reflectance of ＊ C ＊ Lightness L1 in the h color system ＊ １５ and the incident light I1 ４５ The reflected light R1 is received at an angle of 110 degrees with respect to the specular reflection light. １１０ L based on the spectral reflectance of ＊ C ＊ Lightness L1 in the h color system ＊ １１０ But, L1 ＊ １５ -L1 ＊ １１０ ≦15 Fulfilling the relationship, the second coating film has an average light transmittance of 50% or more in the wavelength range of 400 nm to 700 nm; Incident light Im incident on the surface of the multilayer coating film at an angle of 45 degrees ４５ The reflected light Rm received at an angle of 15 degrees to the specular reflected light １５ L based on the spectral reflectance of ＊ C ＊ Chroma Cm in the h color system ＊ １５ and the incident light Im ４５ The reflected light Rm received at an angle of 45 degrees to the specular reflected light ４５ L based on the spectral reflectance of ＊ C ＊ Chroma Cm in the h color system ＊ ４５ But, Cm ＊ １５ >10 Cm ＊ １５ -Cm ＊ ４５ >5 A multi-layer coating that satisfies the above relationship.

2. The second coating composition used to form the second coating film was applied to a black substrate, and incident light I2 was incident at an angle of 45 degrees to the surface of the test coating film obtained. ４５ The reflected light R2 is received at an angle of 15 degrees to the specular reflected light. １５ L based on the spectral reflectance of ＊ C ＊ Chroma C2 in the h color system ＊ １５ but, C2 ＊ １５ ≧5 The multi-layer coating film according to claim 1, which satisfies the relationship:

3. When the color pigment is contained in an amount of 1.0 mass% or less of the second coating film, 2. The multi-layer coating film according to claim 1, wherein the mass ratio of the scaly pigment to the color pigment is 2 or more and 400 or less.

4. The object to be coated A coated article comprising the multi-layer coating film according to claim 1 disposed on the substrate.

5. A method for producing a coated article having a multilayer coating film comprising a first coating film, a second coating film disposed on the first coating film, and a clear coating film disposed on the second coating film, Applying a first coating composition to a substrate to form the first coating film; Applying a second coating composition containing a chromatic, light-interfering, chromatic flake pigment coated with a metal oxide on the first coating to form the second coating; and applying a clear coating composition onto the second coating film to form the clear coating film. the content of the scale-like pigment is 0.5% by mass or more and 20% by mass or less of the second coating film, the second coating film does not contain a color pigment or contains a color pigment in an amount of 1.0% by mass or less of the second coating film; Incident light I1 incident at an angle of 45 degrees to the surface of the first coating film ４５ The reflected light R1 is received at an angle of 45 degrees to the specular reflection light. ４５ L based on the spectral reflectance of ＊ C ＊ Chroma C1 in the h color system ＊ ４５ and lightness L1 ＊ ４５ but, C1 ＊ ４５ ≦15 20≦L1 ＊ ４５ ≦70 Fulfilling the relationship, The incident light I1 ４５ The reflected light R1 is received at an angle of 15 degrees with respect to the specular reflection light. １５ L based on the spectral reflectance of ＊ C ＊ Lightness L1 in the h color system ＊ １５ and the incident light I1 ４５ The reflected light R1 is received at an angle of 110 degrees with respect to the specular reflection light. １１０ L based on the spectral reflectance of ＊ C ＊ Lightness L1 in the h color system ＊ １１０ But, L1 ＊ １５ -L1 ＊ １１０ ≦15 Fulfilling the relationship, the second coating film has an average light transmittance of 50% or more in the wavelength range of 400 nm to 700 nm; Incident light Im incident on the surface of the multilayer coating film at an angle of 45 degrees ４５ The reflected light Rm received at an angle of 15 degrees to the specular reflected light １５ L based on the spectral reflectance of ＊ C ＊ Chroma Cm in the h color system ＊ １５ and the incident light Im ４５ The reflected light Rm received at an angle of 45 degrees to the specular reflected light ４５ L based on the spectral reflectance of ＊ C ＊ Chroma Cm in the h color system ＊ ４５ But, Cm ＊ １５ >10 Cm ＊ １５ -Cm ＊ ４５ >5 A method for manufacturing a coated article that satisfies the above relationship.

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