Multilayer coating film and coated article, and method for producing 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 multilayer coating film, a coated article, and a method for manufacturing a coated article.

Background Art

[0002] The exterior of an automobile usually has a multilayer coating film. Patent Document 1 discloses a laminated coating film having a white coating film appearance.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, due to the diversification of consumer preferences and the pursuit of originality, the designs required for multilayer coating films are diverse. The purpose of the present invention is to provide a multilayer coating film that has a different design from that of Patent Document 1 and exhibits a calm gray color in the face area while having a colored hue in the highlight area.

Means for Solving the Problems

[0005] To solve the above problems, the present invention provides the following aspects. [1] A multilayer coating film including 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, wherein the second coating film contains a flaky pigment coated with a metal oxide, incident light I1 incident at an angle of 45 degrees with respect to the surface of the first coating film 45 is reflected light R1 received at an angle of 45 degrees with respect to the specularly reflected light 45 and the chroma C1 in the L * C * h color system based on the spectral reflectance of* 45 and lightness L1 * 45 satisfy the condition that C1 * 45 ≤ 15 20 ≤ L1 * 45 ≤ 70 and the reflected light R1 45 which receives the incident light I1 15 at an angle of 15 degrees with respect to the specular reflection light * C * lightness L1 in the LCh color system * 15 and the reflected light R1 45 which receives the incident light I1 110 at an angle of 110 degrees with respect to the specular reflection light * C * lightness L1 in the LCh color system * 110 satisfy the condition that L1 * 15 -L1 * 110 ≤ 15 and the average spectral transmittance of the second coating film at wavelengths of 400 nm to 700 nm is 50% or more the incident light Im 45 which is incident on the surface of the multilayer coating film at an angle of 45 degrees 15 and the reflected light Rm * C * chroma Cm in the LCh color system * 15 and the incident light Im 45 and the reflected light Rm 45 which receives the incident light Im * C * chroma Cm in the LCh color system * 45 satisfy the condition that Cm * 15 > 10 Cm * 15-Cm * 45 >5 A multilayer coating film that satisfies the relationship of [2] Incident light I2 incident at an angle of 45 degrees with respect to the surface of a test coating film obtained by coating a second coating composition used for forming the second coating film on a black object to be coated 45 Reflected light R2 received at an angle of 15 degrees with respect to the specularly reflected light 15 L based on the spectral reflectance of * C * Chroma C2 in the h color system * 15 is C2 * 15 ≧5 The multilayer coating film of the above [1] that satisfies the relationship of [3] The content of the flaky pigment is 0.5% by mass or more and 20% by mass or less of the second coating film, and the multilayer coating film of the above [1] or [2]. [4] The second coating film further contains a coloring pigment, The content of the coloring pigment is 0.05% by mass or more and 1.5% by mass or less of the second coating film, and the multilayer coating film of the above [1] or [2]. [5] The mass ratio of the flaky pigment to the coloring pigment is 2 or more and 400 or less, and the multilayer coating film of the above [4]. [6] The object to be coated and The above [1] multilayer coating film disposed on the object to be coated, and a coated article having the same. [7] A method for manufacturing a coated article having a multilayer coating film including 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, comprising: Forming the first coating film by coating a first coating composition on an object to be coated; Forming the second coating film by coating a second coating composition containing a flaky pigment coated with a metal oxide on the first coating film; Forming the clear coating film by coating a clear coating composition on the second coating film, Incident light I1 incident at an angle of 45 degrees with respect to the surface of the first coating film 45 is reflected light R1 received at an angle of 45 degrees with respect to the specular reflection light 45 Based on the spectral reflectance of * C * Chroma C1 in the h color system * 45 And lightness L1 * 45 satisfy the C1 * 45 ≤ 15 20 ≤ L1 * 45 ≤ 70 relationship, and the incident light I1 45 is reflected light R1 received at an angle of 15 degrees with respect to the specular reflection light 15 Based on the spectral reflectance of * C * Lightness L1 in the h color system * 15 and the incident light I1 45 is reflected light R1 received at an angle of 110 degrees with respect to the specular reflection light 110 Based on the spectral reflectance of * C * Lightness L1 in the h color system * 110 satisfy the L1 * 15 -L1 * 110 ≤ 15 relationship, and the average value of the light transmittance of the second coating film at wavelengths of 400 nm to 700 nm is 50% or more, Incident light Im incident at an angle of 45 degrees with respect to the surface of the multilayer coating film 45 is reflected light Rm received at an angle of 15 degrees with respect to the specular reflection light 15 Based on the spectral reflectance of * C * Chroma Cm in the h color system * 15 and the incident light Im 45 is reflected light Rm received at an angle of 45 degrees with respect to the specular reflection light 45 Based on the spectral reflectance of * C* Chroma Cm in the h color system * 45 and Cm * 15 > 10 Cm * 15 -Cm * 45 > 5 A method for manufacturing a painted article that satisfies the relationship of

Advantages of the Invention

[0006] According to the present invention, there are provided a multilayer coating film that exhibits a steady gray color in the face area while a chromatic color tone is felt in the highlight area, a painted article having this multilayer coating film, and a manufacturing method thereof.

Brief Description of the Drawings

[0007]

Figure 1

Modes for Carrying Out the Invention

[0008] [Multilayer Coating Film] The multilayer coating film of the present disclosure includes 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.

[0009] Incident light I1 incident at an angle of 45 degrees with respect to the surface of the first coating film 45 is reflected light R1 received at an angle of 45 degrees with respect to the specularly reflected light 45 Based on the spectral reflectance of * C * Chroma C1 in the h color system * 45 and lightness L1 * 45 are such that C1 * 45 ≤ 15 20 ≤ L1 * 45 ≤ 70 satisfies the relationship. This indicates that the first coating film is in a solid state and within the gray color gamut.

[0010] The first coating film also receives incident light I1 45 and reflects it as reflected light R1 received at an angle of 15 degrees with respect to the specularly reflected light 15 Based on the spectral reflectance of * C * The lightness L1 in the LCh color system * 15 and the reflected light R1 received at an angle of 110 degrees with respect to the specularly reflected light 110 Based on the spectral reflectance of * C * The lightness L1 in the LCh color system * 110 Satisfy L1 * 15 -L1 * 110 ≦15 Satisfy the relationship. This indicates that the first coating film has low flip-flop properties, more specifically, that the first coating film is not a coating film showing high flip-flop properties such as a metallic coating film.

[0011] The average light transmittance of the second coating film in the wavelength range of 400 nm to 700 nm is 50% or more. That is, the second coating film has high light transmittance in the visible light region. As a result, the color tone (gray color) of the first coating film is felt through the second coating film. In other words, the color tone of the first coating film through the second coating film is felt as the design of the multilayer coating film.

[0012] The second coating film contains flaky pigments coated with metal oxides. Since such flaky pigments have light interference properties, the color appears to change depending on the observation direction.

[0013] Incident light Im incident at an angle of 45 degrees with respect to the surface of the multilayer coating film (the surface on the clear coating film side) 45 is reflected as reflected light Rm received at an angle of 15 degrees with respect to the specularly reflected light 15 Based on the spectral reflectance of * C *Chroma Cm in the h color system * 15 and incident light Im 45 are reflected light Rm received at an angle of 45 degrees with respect to the specular reflected light 45 based on the spectral reflectance of * C * Chroma Cm in the h color system * 45 and Cm * 15 > 10 Cm * 15 -Cm * 45 > 5 satisfy the relationship of This indicates that the multilayer coating has a chromatic color tone in the highlight area and that the color tone changes between the highlight area and the face area

[0014] In the present disclosure, a first coating film in a solid gray color gamut having a low chroma, a specific lightness, and a low flip-flop property is combined with a second coating film containing a light-interference flaky pigment (hereinafter sometimes referred to as a light-interference pigment) and having light-transmitting properties. By blending the light-interference pigment in a coating film different from the first coating film, a new design can be expressed in which a solid gray color (achromatic color) is presented in the face area while a chromatic color tone is felt in the highlight area

[0015] The highlight area refers to a range of -25 degrees or more and less than 25 degrees with respect to the specular reflected light of light incident at an angle of 45 degrees. The shade area refers to a range of 75 degrees or more with respect to the specular reflected light of light incident at an angle of 45 degrees. The face area is a range between the highlight area and the shade area (more than 25 degrees and less than 75 degrees with respect to the specular reflected light). In the present disclosure, the chroma at an angle of 15 degrees with respect to the specular reflected light, which can also be called the super-highlight area, is defined as the highlight area

[0016] Chroma C * 45 is incident light I incident at an angle of 45 degrees with respect to the surface of the target coating film 45L based on the spectral reflectance of the reflected light received at an angle of 45 degrees with respect to the specular reflected light * C * is the chroma in the LCh color system. The chroma C * 15 is defined in the same manner as above, except that the incident light I 45 is received at an angle of 15 degrees with respect to the specular reflected light. L * C * In the LCh color system, as the numerical value of the chroma C * increases, the vividness of the target coating film increases, and as it decreases, the dullness increases.

[0017] The lightness L * 45 is the L based on the spectral reflectance of the reflected light received at an angle of 45 degrees with respect to the specular reflected light, where the incident light I 45 is incident on the surface of the target coating film at an angle of 45 degrees. * C * is the lightness in the LCh color system. The lightness L * 15 and the lightness L * 110 are defined in the same manner as above, except that the incident light I 45 is received at an angle of 15 degrees or 110 degrees with respect to the specular reflected light. L * C * In the LCh color system, as the numerical value of the lightness L * increases, the brightness of the target coating film increases, and as it decreases, the darkness increases.

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

[0019] Chroma C * and lightness L * can be obtained using a spectrophotometer (e.g., BYK Gardner, BYK-mac i).

[0020] Figure 1 is a diagram for explaining the light-receiving angle. Incident light I incident at an angle of 45 degrees with respect to the surface of the coating film 45 is indicated by R0 for the specularly reflected light. Incident light I 45 is indicated by R for the reflected light received at an angle of 15 degrees toward the incident light with respect to the specularly reflected light of the incident light. 15 For the reflected light R 15 lightness L * 15 and chroma C * 15 are calculated. For the specularly reflected light of incident light I 45 is indicated by R for the reflected light received at an angle of 45 degrees toward the incident light with respect to the specularly reflected light of the incident light. 45 For the light R 45 lightness L * 45 and chroma C * 45 are calculated. For the specularly reflected light of incident light I 45 is indicated by R for the reflected light received at an angle of 110 degrees toward the incident light with respect to the specularly reflected light of the incident light. 110 For the reflected light R 110 lightness L * 110 is calculated.

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

[0022] Chroma C1 of the first coating film *45 and lightness L1 * 45 is C1 * 45 ≤ 15 20 ≤ L1 * 45 ≤ 70 satisfies the relationship of

[0023] Since the first coating film is in the gray color gamut, the characteristics of the light-interference pigment contained in the second coating film are exerted, and the multilayer coating film produces a desired color tone in the highlight region.

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

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

[0026] The spectral reflectance of the reflected light R1 is measured for the single first coating film, not for the multilayer coating film. The single first coating film refers to the cured coating film of the first coating composition applied to the object to be coated. The single first coating film is obtained by spray-coating the object to be coated, which has been coated with a cationic electrodeposition paint and an intermediate coat paint on a steel plate and heat-cured respectively, with the first coating composition used for forming the first coating film so that the dry coating film has a thickness of 3 μm or more and 20 μm or less (typically 15 μm), and then heat-curing at 140 °C for 20 minutes.

[0027] The lightness L1 of the first coating film * 15 and the lightness L1 * 110 are L1 * 15 -L1 * 110 ≤ 15 satisfies the relationship.

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

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

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

[0031] The spectral reflectance of the reflected light R1 of the first coating film can be adjusted, for example, by 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, may be 14 μm or less, may be 13 μm or less.

[0033] (Second coating film) The second coating film contains a light-interference pigment. The light-interference pigment exhibits a chromatic color tone that varies depending on the observation direction. Therefore, the color tone of the multilayer coating film becomes more vivid as it goes from the face area to the highlight area. The second coating film is typically a cured product of a second coating composition containing a light-interference pigment and a film-forming resin.

[0034] The light transmittance of the second coating film can affect the design property of the multilayer coating film. The average light transmittance of the second coating film at wavelengths of 400 to 700 nm is 50% or more. Thereby, the color tone of the first coating film can be felt through the second coating film. The average light transmittance of the second coating film may be 60% or more, and 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 second coating film alone, not for the multilayer coating film. The second coating film alone refers to a cured product of a film-like second coating composition. The second coating film alone is obtained by spray-coating a 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), heat-curing at 140 °C for 20 minutes, and then peeling the coating film from the polypropylene plate.

[0036] The light transmittance is measured for the second coating film alone using a spectrophotometer (for example, manufactured by Hitachi, trade name: U-4100) in the wavelength range of 400 to 700 nm under the conditions of wavelength scan mode, scan speed of 60 nm / min, and sampling interval of 2 nm. The arithmetic mean value of the obtained light transmittance every 10 nm is taken as the average light transmittance.

[0037] Incident light I2 45 incident at an angle of 45 degrees with respect to the surface of a test coating film obtained by coating the second coating composition on a black coated object 15 is the L * C * chroma C2 in the h color system based on the spectral reflectance of the reflected light R2 * 15 is C2 *15 ≧5 may satisfy the relationship. That is, the second coating film itself may also have a chromatic color tone in the highlight region. Thereby, the Cm of the multilayer coating film * 15 tends to be greater than 10.

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

[0039] The black object to be coated has a black part 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 Rate Test Paper Method. Specifically, it is a thing obtained by coating a solvent-resistant transparent paint on an art paper of about 174 mm × 144 mm having a white part and a black part, and the 45-degree and 0-degree diffuse reflectance are 80 ± 1 in the white part and 2 or less in the black part.

[0040] The average light transmittance of the second coating film and the spectral reflectance of the reflected light R2 15 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 light-interference pigment may be 0.5% by mass or more and 20% by mass or less of the second coating film. Thereby, the light transmittance of the second coating film and the spectral reflectance of the reflected light R2 15 are easily adjusted to the above ranges. In addition, when the above content of the light-interference pigment is 20% by mass or less, the surface of the second coating film tends to be smooth, and the appearance degradation of the multilayer coating film is suppressed.

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

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

[0044] In terms of not disturbing the light interference by the light-interference pigment, the content of the coloring pigment may be 0.05% by mass or more and 1.5% by mass or less of the second coating film. The above content of the coloring pigment may be 0.1% by mass or more, and may be 0.2% by mass or more. The above content of the coloring pigment may be 1.3% by mass or less, may be 1.0% by mass or less, and may be 0.9% by mass or less.

[0045] The mass ratio of the light-interference pigment to the coloring pigment (light-interference pigment / coloring pigment) may be 2 or more and 400 or less. Thereby, it is difficult to prevent the expression of the interference color by the light-interference pigment. The above mass ratio may be 10 or more, and may be 20 or more. The above mass ratio may be 300 or less, may be 200 or less, and may be 75 or less.

[0046] The primary particle diameter of the coloring pigment is not particularly limited. In terms of making it difficult to prevent the expression of the interference color by the light-interference pigment, the primary particle diameter of the coloring pigment may be 3 nm or more and 500 nm or less. The primary particle diameter can be measured from an image of an electron microscope of the cross-section of the multilayer coating film using image processing software.

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

[0048] ·Light-interference pigment The light-interference pigment has a flaky base material and a metal oxide coating its surface. Since the light refractive indices of the base material and the metal oxide are different, multiple reflections of light occur and an interference color is expressed. The light-interference pigment is used alone or in combination of two or more.

[0049] Examples of the base material include mica, artificial mica, glass, silica, iron oxide, and aluminum oxide. Among them, mica, artificial mica, and aluminum oxide may be used.

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

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

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

[0053] The average particle size is the 50% average particle size (D50) in the volume-based particle size distribution measured using a particle size distribution measuring device based on the laser diffraction / scattering method. Examples of the particle size distribution measuring device include UPA-150 (manufactured by Nikkiso Co., Ltd., Microtrac particle size distribution measuring device).

[0054] Examples of the metal oxide include titanium oxide and iron oxide. The thickness of the coating film of the metal oxide is not particularly limited and may be appropriately selected according to the desired interference color. The interference color varies depending on the thickness of the coating film. The chroma of the second coating film and the multilayer coating film can change depending on the thickness of the coating film.

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

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

[0057] Commercially available products of mica coated with a metal oxide include, for example, the "Ultimica" series and "TWINCLE PEARL" series manufactured by Nippon Kogaku 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 products of alumina flakes coated with a metal oxide include, for example, the "Xirallic" series manufactured by MERCK and the "Adamas" series manufactured by CQV.

[0059] · Coloring pigment The coloring pigment absorbs, reflects, or scatters light to impart color to the coating film. The coloring pigment may be an inorganic substance or an organic substance. The coloring pigment may be a chromatic color or an achromatic color. Examples of the organic coloring pigment 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 the inorganic coloring pigment include lead yellow, 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 film) The clear coating film protects the first and second coating films. The clear coating film 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. The thickness of the clear coating film may be 20 μm or more. The thickness of the clear coating film may be 50 μm or less.

[0062] (Chroma and lightness of the multilayer coating film) Chroma Cm * 15 may be 12 or more and may be 13 or more. Cm * 15 may be 50 or less, may be 40 or less, and may be 35 or less.

[0063] Chroma Cm * 45 may be 10 or less and may be 9.0 or less. Cm * 45 may be 1.0 or more and may be 1.1 or more.

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

[0065] Lm * 45 is, for example, 30 or more and 65 or less. As a result, it is felt as a gray color in the face area. Lm * 45 may be 32 or more and may be 35 or more. Lm * 45 may be 65 or less and may be 62 or less.

[0066] [Coated article] The painted article according to the present disclosure has an object to be painted and the above-mentioned multilayer coating film disposed on the object to be painted. In the painted article, the clear coating film is disposed on the outside. The painted article having the above-mentioned multilayer coating film has an unprecedented design in that it exhibits a steady gray color in the face area while a colored tint is felt in the highlight area.

[0067] (Object to be painted) Examples of the material of the object to be painted include metal, plastic, and foam. Among them, it may be metal (especially casting) and may be a metal capable of electrocoating. Examples of such metals include iron, copper, aluminum, tin, zinc, etc. and alloys containing these metals.

[0068] The shape of the object to be painted is not particularly limited and may be flat or three-dimensionally formed. Specific examples of the object to be painted include automobile bodies such as passenger cars, trucks, motorcycles, and buses, and their parts.

[0069] The metal object to be painted may be subjected to chemical conversion treatment using a phosphoric acid-based chemical conversion treatment agent, a zirconium-based chemical conversion treatment agent, etc., and electrocoating. The electrocoating composition may be cationic or anionic. The cationic electrocoating composition can form a coating film with excellent corrosion resistance.

[0070] The metal object to be painted may be provided with an electrocoating film and an intermediate coating film disposed thereon. The intermediate coating film is usually provided for the purpose of improving the adhesion and durability of the multilayer coating film. The coating composition for the intermediate coating may include, for example, a film-forming resin, a curing agent, a coloring pigment, and a extender pigment. Examples of the film-forming resin and the curing agent include the same ones as those contained in the first coating composition.

[0071] [Method for manufacturing a painted article] The manufacturing method of a painted article according to the present disclosure includes: coating a first paint composition on an object to be painted to form a first paint film; coating a second paint composition containing a light-interference pigment on the first paint film to form a second paint film; and coating a clear paint composition on the second paint film to form a clear paint film.

[0072] In one aspect, the painted article is manufactured by sequentially coating the first paint composition and the second paint composition on the object to be painted, then curing, and then coating and curing the clear paint composition. Before coating the second paint composition after coating the first paint composition, preheating may be performed.

[0073] In another aspect, the painted article is manufactured by sequentially coating the first paint composition, the second paint composition, and the clear paint composition on the object to be painted in a wet-on-wet manner and then curing these paint compositions at once. Before coating the second paint composition after coating the first paint composition, and before coating the clear paint composition after coating the second paint composition, preheating may be performed.

[0074] Examples of the coating method include multi-stage coating (preferably two-stage coating) by air spray coating, airless spray coating, electrostatic spray coating, air electrostatic spray coating, and coating by combining air electrostatic spray coating and a rotary atomization type electrostatic coater.

[0075] The curing of each paint composition is performed, for example, under the conditions of a heating temperature of 80°C to 180°C (preferably 100°C to 160°C) and a heating time of 5 minutes to 60 minutes (preferably 10 minutes to 30 minutes).

[0076] (First paint composition) The first paint composition includes pigments for adjusting lightness (typically white pigments and black pigments) and a film-forming resin. The first coating composition may be aqueous or solvent-based. The aqueous first coating composition may contain water and, optionally, a water-soluble or water-miscible organic solvent as the main solvent. The solvent-based first coating composition may contain, for example, an ester-based solvent, an ether-based solvent, an alcohol-based solvent, a ketone-based solvent, an aliphatic hydrocarbon-based solvent, or an aromatic-based solvent as the main solvent. The first coating composition may be diluted with a solvent suitable for painting and then used. The first coating composition may be aqueous. The main solvent occupies 50% by mass or more of the total solvent.

[0077] 《White Pigment》 The white pigment is not particularly limited. Examples of the white pigment 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. Among them, from the viewpoint of weather resistance, rutile-type titanium dioxide may be used. The surface of titanium dioxide may be treated with an inorganic compound such as silica, zirconium, or aluminum.

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

[0079] The blending amount of the white pigment is not particularly limited. The white pigment is C1 * 45 ≦15 20≦L1 * 45 ≦70 blended so as to satisfy the relationship.

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

[0081] "Black Pigment" The black pigment is not particularly limited. Examples of the black pigment include carbon black; composite metal oxides such as iron chromium and bismuth manganese; perylene pigments; and azomethiazole pigments. These can be used individually 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 perspective of hiding power, the primary particle size of the black pigment may be 20 nm or more and 70 nm or less, and may be 30 nm or more and 60 nm or less.

[0083] The blending amount of the black pigment is not particularly limited. The black pigment is C1 * 45 ≦15 20≦L1 * 45 ≦70 blended so as to satisfy the relationship of.

[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 may be 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 may be 3% by mass or less of the first coating film.

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

[0086] "Coating Film Forming Resin" Examples of the coating film forming resin include acrylic resin, acrylic silicone resin, polyester resin, polyurethane resin, epoxy resin, fluororesin, and silicone resin. These can be used individually or in combination of two or more. Among them, it may be acrylic resin.

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

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

[0089] Examples of (meth)acrylate 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)acrylate esters represent acrylate esters and methacrylate 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 the α,β-ethylenically unsaturated monomer 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 the 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 method of emulsion polymerization is not particularly limited. For example, an emulsifier is dissolved in an aqueous medium containing water or an organic solvent such as alcohol or ether (e.g., dipropylene glycol methyl ether, propylene glycol methyl ether, etc.) as required, 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 pre-emulsified with an emulsifier.

[0094] As the polymerization initiator and the emulsifier, those commonly used by those skilled in the art can be used. If necessary, the molecular weight may be adjusted using a chain transfer agent such as mercaptan (e.g., lauryl mercaptan) and α-methylstyrene dimer. The reaction temperature, reaction time, etc. can be appropriately selected within the range commonly used by those skilled in the art. The obtained acrylic resin emulsion is neutralized with a base as required.

[0095] The acrylic resin obtained by emulsion polymerization (emulsion of acrylic resin) 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 a standard. The acid value and hydroxyl value of the film-forming resin are calculated from the monomer composition used in the preparation based on the provisions of JIS.

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

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

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

[0100] 《Hardener》 The first coating composition may contain a hardener. The hardener reacts with the film-forming resin to form a first coating film together with it.

[0101] Examples of the hardening agent include melamine resin, blocked isocyanate compound, epoxy compound, aziridine compound, carbodiimide compound, oxazoline compound, and metal ion. These may be used alone or in combination of two or more. Among them, at least one of melamine resin and blocked isocyanate compound 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 via three nitrogen atoms around a melamine nucleus (triazine nucleus). Generally, the melamine resin is composed of a polynuclear body in which a plurality of melamine nuclei are bonded to each other. The melamine resin may also be a mononuclear body consisting of one melamine nucleus.

[0103] Commercially available melamine resins may be used. Examples of commercially available melamine resins include 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, Cymel 1141; and Uban (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 active hydrogen to a polyisocyanate composed of trimethylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, etc.

[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 above content of the curing agent may be 15% by mass or more. The above content of the curing agent may be 60% by mass or less.

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

[0107] 《Other Pigments》 The first coating composition (first coating film) may further contain pigments other than the white pigment and the black pigment. Examples of other pigments include colored pigments, extender pigments, rust preventive pigments, and bright pigments (including optical interference pigments). Other pigments are blended within a range that does not interfere with the characteristics and functions of the first coating film.

[0108] 《Additives》 The first coating composition may contain additives commonly used by those skilled in the art. Examples of additives include surface modifiers, viscosity control agents, thickeners, antioxidants, ultraviolet light inhibitors, and defoamers.

[0109] (Second Coating Composition) The second coating composition contains an optical interference pigment and a film-forming resin. The second coating composition may further contain a coloring pigment. The second coating composition may be aqueous or solvent-based. The second coating composition may be aqueous. The solvent contained in the second coating composition and its preparation method are the same as those of the first coating composition.

[0110] 《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 of the same type or different types. 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 photochromic pigment. Examples of other pigments include coloring pigments (including white pigments and black pigments), extender pigments, rust preventive pigments, and bright pigments other than the photochromic pigment. Other pigments are blended within a range that does not interfere with the properties and functions of the second coating film.

[0112] 《Phosphate Group-Containing Organic Compound》 The second coating composition may further contain a phosphate group-containing organic compound. The phosphate group-containing compound makes it easier to improve the dispersibility of flaky pigments (e.g., photochromic 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 above content of the phosphate group-containing compound may be 1% by mass or more. The above 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 R is independently hydrogen or a hydrocarbon group). The phosphate group-containing compound is, for example, 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 with 4 to 30 carbon atoms. Examples of the alkyl phosphate ester include monoalkyl phosphate esters, dialkyl phosphate esters, and mixtures thereof. In the dialkyl phosphate ester, the two alkyl groups may be the same or different. The dialkyl phosphate ester preferably has two identical alkyl groups.

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

[0117] Examples of the alkyl phosphate ester 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 (a mixture of monotridecyl phosphate ester and ditridecyl phosphate ester), monostearyl acid phosphate, distearyl acid phosphate, stearyl acid phosphate (a mixture of monostearyl phosphate ester and distearyl phosphate ester), isostearyl acid phosphate (a mixture of monoisostearyl phosphate ester and diisostearyl phosphate ester), oleyl acid phosphate (a mixture of monooleyl phosphate ester and dioleyl phosphate ester), and behenyl acid phosphate (a mixture of monobehenyl phosphate ester and dibehenyl phosphate ester).

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

[0119] The phosphate group value is the number of milligrams of potassium hydroxide (KOH) required for neutralization, which is calculated based on the blending amount of phosphate group-containing components such as phosphate esters used in the preparation of 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, and may be 5,000 or more. The number average molecular weight of the phosphate group-containing polymer may be 30,000 or less, and may be 20,000 or less.

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

[0122] 《Additive》 The second coating composition may contain additives commonly used by those skilled in the art. Examples of the additives include those exemplified as being contained in the first coating composition.

[0123] (Clear Coating Composition) The clear coating composition may be solvent-based, water-based, or powder-based. 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 curable clear coating composition contains, for example, an acrylic resin (a) containing an acid anhydride group, 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 acrylic resin (a) containing an acid anhydride group may be half-esterified with a low molecular weight alcohol or the like. The carboxyl group-containing polyester resin (b) may further have a hydroxyl group.

[0126] The above resins (a) to (c) are formulated such that, for example, the molar ratio of the carboxyl group contained in the acrylic resin (a) and the polyester resin (b) to the epoxy group 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 group derived from the acid anhydride group contained in the acrylic resin (a) to the hydroxyl group 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 curable 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; alicyclic 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 such as their burette bodies and nurate bodies.

[0128] The hydroxyl value of the hydroxyl group-containing resin is, for example, 20 mgKOH / g or more and 200 mgKOH / g or less. The above hydroxyl value may be 30 mgKOH / g or more. The above hydroxyl value may be 180 mgKOH / g or less. The weight average molecular weight of the hydroxyl group-containing resin is, for example, 1000 or more and 20000 or less. The above weight average molecular weight may be 2000 or more. The above weight average molecular weight may be 15000 or less. The acid value of the hydroxyl group-containing resin is, for example, 2 mgKOH / g or more and 30 mgKOH / g or less. The above acid value may be 3 mgKOH / g or more. The above 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 above equivalent ratio may be 0.7 or more. The above equivalent ratio may be 1.5 or less.

[0130] In addition, an acrylic melamine-curing type clear paint composition may be used.

Examples

[0131] The present invention will be described more specifically by the following examples, but the present invention is not limited thereto. In the examples, "parts" and "%" are based on mass unless otherwise specified.

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

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

[0134] [Production Example 1] Production of Acrylic Resin Emulsion 633 parts of deionized water was added to a reaction vessel, and the temperature was raised to 80 °C while mixing and stirring in a nitrogen stream. Separately, 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) were mixed to prepare a first-stage monomer mixture. Next, this monomer mixture was mixed with 25.0 parts of Aqualon HS-10 (polyoxyethylene alkyl propenyl phenyl ether sulfate ester, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and 25.0 parts of Adeka Resin Soap 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 of ammonium persulfate and 500 parts of deionized water was prepared. The monomer emulsion and the initiator solution were added dropwise in parallel to the above reaction vessel over 1.5 hours. After completion of the dropwise addition, aging was carried out at the same temperature for 1 hour.

[0135] Furthermore, separately, 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 were mixed to prepare a second-stage monomer mixture. Then, this monomer mixture was 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 the initiator solution were simultaneously dropped into the above reaction vessel over 1.5 hours. After the dropping was completed, aging was carried out at the same temperature for 2 hours.

[0136] Next, the reaction product was 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 this reaction product to adjust the pH to 6.5. In this way, an acrylic resin emulsion with an average particle diameter of 150 nm, a solid content concentration of 35%, a solid content acid value of 20 mgKOH / g, and a hydroxyl value of 100 mgKOH / g was obtained.

[0137] [Production Example 2] Production of Phosphoric Acid Group-Containing Polymer 40 parts of ethoxypropanol were charged into a 1-liter reaction vessel equipped with a stirrer, a temperature controller, and a cooling pipe. Separately, 20 parts of ethoxypropanol was dissolved with 20 parts of Hostmer PP (acid phosphooxyhexa(oxypropylene) monomethacrylate manufactured by Uni-Chemical Co., Ltd.) to prepare a solution. 40 parts of this solution, 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 were mixed to prepare a monomer solution. 121.7 parts of the monomer solution was added dropwise to the above reaction vessel at 120 °C over 3 hours. The mixture was further stirred for 1 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 value of 60 mgKOH / g, a number average molecular weight of 6,000, and a solid content 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 temperature was raised to 105 °C while mixing and 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, and 100 parts of the monomer mixture, 10.0 parts of tripropylene glycol methyl ether, and an initiator solution consisting of 1 part of tertiary butyl peroxy 2-ethylhexanoate were added dropwise to the reaction vessel in parallel over 3 hours. After completion of the dropwise addition, aging was carried out at the same temperature for 0.5 hour.

[0139] Furthermore, an initiator solution consisting of 5.0 parts of tripropylene glycol methyl ether and 0.3 part of tertiary butyl peroxy 2-ethylhexanoate was added dropwise to the reaction vessel over 0.5 hour. After completion of the dropwise addition, aging was carried out at the same temperature for 2 hours.

[0140] Using a desolventizing apparatus, after distilling off 16.1 parts of the solvent at 110°C under reduced pressure (70 torr), 204 parts of deionized water and 7.1 parts of dimethylaminoethanol were added to obtain a water-soluble acrylic resin solution. The solid content concentration of the obtained water-soluble acrylic resin solution was 30%, the solid content acid value was 40 mgKOH / g, the hydroxyl value was 50 mgKOH / g, and the viscosity was 140 poise (E-type viscometer, 1 rpm / 25°C).

[0141] [Example 1] (1) Preparation of the first paint composition (1-1) Preparation of the colored 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 part 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 part of an antifoaming agent (trade name: BYK-011) were mixed with a stirrer. Subsequently, using a disperser filled with zirconia beads of 0.05 mm at a volume filling ratio of 70%, this mixture was dispersed to obtain the colored pigment dispersion A1.

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

[0143] (2) Preparation of the second paint 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 light-interference pigment A (trade name: Xirallic T60-23, manufactured by MERCK), 1.7 parts of light-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 part of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts (3 parts in terms of solid content) of surfactant (trade name: Neugen EA-207D), and 3 parts of linoleic acid (manufactured by Kishida Chemical Co., Ltd.) were uniformly dispersed. To this dispersion, dimethylaminoethanol was added so that the pH became 8.1, and it was diluted with deionized water to prepare an aqueous second coating composition having a total solid content concentration of 25%.

[0144] (3) Preparation of clear coating composition As the clear coating composition, an acid epoxy-curing type clear coating (trade name: MacFlow-O-1810 Clear, manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was prepared.

[0145] (4) Formation of multilayer coating film On a phosphatized cold-rolled steel sheet with a thickness of 0.8 mm, a length of 30 cm, and a width of 40 cm, "Power Top U-50)" which is a cationic electrodeposition coating composition (manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was electrodeposition-coated so that the dry film thickness became 20 μm, and baked at 160 °C for 30 minutes. On the obtained coated plate, the intermediate coating composition "OP-30P Middle Gray" (manufactured by Nippon Paint Automotive Coatings Co., Ltd., polyester-melamine-based paint, diluted in advance for 25 seconds (measured at 20 °C using a No. 4 Ford cup)) was air-sprayed using an Anest Iwata air spray gun W-101-132G so that the dry film thickness became 35 μm, and heated at 140 °C for 30 minutes. In this way, an object to be coated having an electrodeposition coating film and an intermediate coating film was obtained.

[0146] The substrate was air-sprayed with the first paint composition to a dry film thickness of 10 μm under the conditions of a room temperature of 23°C and a humidity of 68%. After setting for 1.5 minutes, the second paint composition was air-sprayed wet-on-wet to a dry film thickness of 10 μm under the conditions of a room temperature of 23°C and a humidity of 68%. After setting for 3 minutes, preheating was carried out at 80°C for 3 minutes. The painted panel was allowed to cool to room temperature, and the clear paint composition was air-sprayed to a dry film thickness of 35 μm and set for 7 minutes. Finally, this painted panel was heated in a dryer at 140°C for 30 minutes to obtain a painted article having a multilayer coating film.

[0147] [Example 2] (1) Preparation of the first paint composition A colored 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 part of a black pigment (carbon black) were mixed. The first paint composition was prepared in the same manner as in Example 1, except that the colored pigment dispersion A2 was used instead of the colored pigment dispersion A1.

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

[0149] A multilayer coating film and a painted article were obtained in the same manner as in Example 1, except that the above first paint composition and second paint composition were used.

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

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

[0152] [Example 4] (1) Preparation of the first coating composition A colored 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 colored pigment 3 (quinacridone red, trade name: Rubicron 400RG, manufactured by DIC Corporation), and 0.8 part of a colored pigment 4 (cyanine blue, trade name: Cyanine Blue G-314R, manufactured by Sanyo Color Works Co., Ltd.) were mixed. The first coating composition was prepared in the same manner as in Example 1, except that the colored pigment dispersion A4 was used instead of the colored pigment dispersion A1.

[0153] (2) Preparation of the second coating composition (2-1) Preparation of the colored pigment dispersion B1 10 parts of the water-soluble acrylic resin solution of Production Example 3, 35 parts of a colored pigment 1 (titanium dioxide), 2.5 parts of a colored pigment 2 (carbon black), 0.3 part of a colored pigment 3, 0.3 part of a colored 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, the mixture was dispersed using a disperser filled with zirconia beads having a diameter of 0.05 mm at a volume filling ratio of 70% to obtain a colored pigment dispersion B1.

[0154] (2-2) Preparation of the 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 light-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 part of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts (3 parts in terms of solid content) of surfactant (trade name: Neugen EA-207D), and 3 parts of linoleic acid (manufactured by Kishida Chemical Co., Ltd.) were uniformly dispersed. To this dispersion, dimethylaminoethanol was added to adjust the pH to 8.1, and then diluted with deionized water to prepare an aqueous second paint composition having a total solid content concentration of 25%.

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

[0156] [Example 5] (1) Preparation of the first paint composition A colored pigment dispersion A5 was prepared in the same manner as in Example 1 except that 39 parts of a white pigment (titanium dioxide), 1.9 parts of a black pigment (carbon black), 0.2 part of colored pigment 3, 0.4 part of colored pigment 4, and 1.2 parts of a bright pigment b (trade name: MH-8801, manufactured by Asahi Kasei Corporation, flaky aluminum pigment paste, active ingredient 63.7%) were mixed so as to be 1.2 parts with respect to 100 parts of the solid content of the first paint composition. The first paint composition was prepared in the same manner as in Example 1 except that colored pigment dispersion A5 was used instead of colored pigment dispersion A1.

[0157] (2) Preparation of the second paint composition (2-1) Preparation of colored pigment dispersion B2 10 parts of the water-soluble acrylic resin solution of Production Example 2, 6 parts of colored pigment 2 (carbon black), 2.7 parts of colored pigment 3, 2.2 parts of colored 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 zirconia beads having a diameter of 0.05 mm at a volume filling rate of 70% to obtain colored pigment dispersion B2.

[0158] (2-2) Preparation of the 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 the light interference pigment F, and another bright pigment b (scaly aluminum pigment paste, trade name: MH-8801, manufactured by Asahi Kasei Chemicals Corporation, active ingredient 63.7%) in an amount of 0.2 part per 100 parts of the solid content of the second coating composition, 1.6 parts of the colored pigment dispersion B2, 5 parts of the phosphate group-containing polymer of Production Example 2, 0.4 part of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of a surfactant (trade name: Neugen EA-207D) (3 parts in terms of solid content), and 3 parts of linoleic acid (manufactured by Kishida Chemical Co., Ltd.) were uniformly dispersed. To this dispersion, dimethylaminoethanol was added so that the pH became 8.1, and it was diluted with deionized water to prepare an aqueous second coating composition having a total solid content concentration of 25%.

[0159] A multilayer 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 the First Coating Composition A colored 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 bright pigment b were mixed so as to be 9.5 parts per 100 parts of the solid content of the first coating composition. The first coating composition was prepared in the same manner as in Example 1, except that the colored pigment dispersion a1 was used instead of the colored pigment dispersion A1.

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

[0162] A multilayer 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 the first coating composition A colored 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 part of a black pigment (carbon black), 1 part of a colored pigment 3, and 2.5 parts of a colored pigment 4 were mixed. The first coating composition was prepared in the same manner as in Example 1, except that the colored pigment dispersion a2 was used instead of the colored pigment dispersion A1.

[0164] A multilayer 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 the first coating composition A colored 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 part of a black pigment (carbon black) were mixed. The first coating composition was prepared in the same manner as in Example 1, except that the colored pigment dispersion a3 was used instead of the colored pigment dispersion A1.

[0166] A multilayer 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 the first coating composition A colored pigment dispersion a4 was prepared in the same manner as in Example 1, except that 0.7 part of a white pigment (titanium dioxide), 7 parts of a black pigment (carbon black), and 5.5 parts of a colored pigment 4 were mixed. The first coating composition was prepared in the same manner as in Example 1, except that the colored pigment dispersion a4 was used instead of the colored pigment dispersion A1.

[0168] A multilayer 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 the first coating composition A colored 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 part of a black pigment (carbon black) were mixed. A first paint composition was prepared in the same manner as in Example 1, except that the colored pigment dispersion a5 was used instead of the colored pigment dispersion A1.

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

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

[0172] [Comparative Example 6] (2) Preparation of the second paint composition (2-1) Preparation of the colored pigment dispersion b1 10 parts of the water-soluble acrylic resin solution of Production Example 2, 5.8 parts of the colored pigment 2, 6.9 parts of the colored pigment 4, 0.2 part of the colored 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 zirconia beads having a diameter of 0.05 mm at a volume filling ratio of 70% to obtain a colored pigment dispersion b1.

[0173] (2-2) Preparation of the second paint 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 part of light-interference pigment A, 1.2 parts of light-interference pigment D (trade name: Xirallic T60-22, manufactured by MERCK), 0.5 part of light-interference pigment E, 0.7 part of light-interference pigment G (trade name: VXC-SO, manufactured by Nippon 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 part of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts (3 parts in terms of solid content) of surfactant (trade name: Neugen EA-207D), and 3 parts of linoleic acid (manufactured by Kishida Chemical Co., Ltd.) were uniformly dispersed. To this dispersion, dimethylaminoethanol was added so that the pH became 8.1, and it was diluted with deionized water to prepare an aqueous second coating composition having a total solid content concentration of 15%.

[0174] A multilayer 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 the second coating composition (2-1) Preparation of colored pigment dispersion b2 10 parts of the water-soluble acrylic resin solution of Production Example 2, 29.4 parts of colored pigment 1, 0.7 part of colored pigment 2, 1.9 parts of colored pigment 4, 2.3 parts of colored pigment 5, 3 parts of pigment dispersant (trade name: DISPEX ULTRA PA 4550AN), 49.2 parts of ion-exchanged water, and 0.5 part of antifoaming agent (trade name: BYK-011) were mixed with a stirrer. Subsequently, using a disperser filled with zirconia beads of 0.05 mm at a volume filling rate of 70%, this mixture was dispersed to obtain colored pigment dispersion b2.

[0176] (2-2) Preparation of the 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), 4.3 parts of light-interference pigment A, 4.3 parts of light-interference pigment F, 5.1 parts of other bright pigment b, 13.5 parts of colored pigment dispersion b2, 5 parts of the phosphate group-containing polymer of Production Example 2, 0.4 part of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts (3 parts in terms of solid content) of surfactant (trade name: Neugen EA-207D), 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 then it was diluted with deionized water to prepare an aqueous second coating composition with a total solid content concentration of 25%.

[0177] A multilayer (two-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 and the first coating composition was not used.

[0178] [Evaluation] The following evaluations were performed using the multilayer coating films, single first coating films, or single second coating films obtained in the examples and comparative examples. The evaluation results are shown in the following table.

[0179] In the table, the mass (%) of the pigment contained in the second coating film is the ratio when the second coating film (solid content of the second coating composition) is set to 100% by mass.

[0180] (Preparation of single first coating film) The above first coating composition was spray-coated on the object to be coated obtained in the same manner as in Example 1 so that the dry coating film thickness was 15 μm, and then heat-cured at 140 °C for 20 minutes. Thereby, a cured coating film (single first coating film) of the first coating composition coated on the object to be coated was obtained.

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

[0182] (Preparation of Test Coating Film) An art paper measuring approximately 174 mm × 144 mm with white and black parts was coated with a solvent-resistant transparent paint. A coated object with a 45-degree and 0-degree diffuse reflectance of 80 ± 1 in the white part and 2 or less in the black part was prepared.

[0183] The above second coating composition was spray-coated onto the coated object so that the dry film thickness was 15 μm, and then heat-cured at 140 °C for 20 minutes. Thereby, a cured coating film (test coating film) of the second coating composition coated on the black coated object was obtained.

[0184] (1) Lightness and Chroma Using a spectrophotometer (BYK Gardner, BYK-mac i), the lightness and chroma of a single first coating film, test coating film, or multilayer coating film were measured.

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

[0186] (3) Solid Feeling The multilayer coating film was viewed from angles corresponding to a light-receiving angle of 45° (face area) and 110 °C (shade area), and evaluated based on the following criteria. If no particle feeling is felt, it can be evaluated as having a solid feeling. In the case of an A evaluation, it can be said to be a desired design.

[0187] Evaluation Criteria A: Only a sparse particle feeling due to the bright pigment is felt in the face area, and almost no particle feeling is felt in the shade area. B: A particle feeling is felt overall in the face area, but only a sparse particle feeling is felt in the shade area. C: A particle feeling is felt overall in both the face area and the shade area.

[0188] (4) Gray feeling Chroma Cm of the multilayer coating film * 45 and lightness Lm * 45 were evaluated based on the following criteria. If it is an A evaluation, a gray feeling can be felt.

[0189] Evaluation criteria A: Cm * 45 ≤10 and 30 ≤ Lm * 45 ≤65 are satisfied B: 10 < Cm * 45 ≤12 and 27 ≤ Lm * 45 ≤68 are satisfied, or Cm * 45 ≤12 and 27 ≤ Lm * 45 <30 are satisfied, or Cm * 45 ≤12 and 65 < Lm * 45 ≤68 are satisfied C: Cm * 45 >12 or Lm * 45 <27 or * 45 >68 are satisfied

[0190] (5) Hue Chroma Cm of the multilayer coating film * 15 was evaluated based on the following criteria. If it is an A evaluation, a hue can be felt.

[0191] Evaluation criteria A: Cm * 15 >10 are satisfied B: 7 < Cm * 15 ≤10 are satisfied C: Cm * 15 ≤7

[0192]

Table 1

[0193] All of the multilayer coatings of the examples were coatings having a unique design such that they were visually recognized as gray solid coatings in the face region while having a colored hue in the highlight region. Comparative Example 1 is an example of a metallic coating having a high flip-flop value of the first coating. The multilayer coating of Comparative Example 1 did not have a colored hue in the highlight region and also did not have a solid feeling. Comparative Example 2 is an example having a high chroma of the first coating. The multilayer coating of Comparative Example 2 did not have a gray feeling and did not have the design intended by the present disclosure. Comparative Examples 3 and 4 are examples where the lightness of the first coating is outside the range of the present disclosure. These multilayer coatings did not have a gray feeling and did not have the design intended by the present disclosure. Comparative Example 5 is an example where the chroma of the multilayer coating is outside the range of the present disclosure. In the multilayer coating of Comparative Example 5, a colored hue was not felt in the highlight region. Comparative Example 6 is an example where the average light transmittance of the second coating is low. In the multilayer coating of Comparative Example 6, since the transparency of the second coating was low, the gray feeling of the first coating could not be recognized and it did not have a solid feeling either. Comparative Example 7 is an example including a pigment (white pigment and black pigment) for adjusting lightness and a flaky pigment in one coating. The coating of Comparative Example 7 did not have a solid feeling in the face region.

[0194] The present disclosure includes the following aspects. [1] A multilayer coating including a first coating, a second coating disposed on the first coating, and a clear coating disposed on the second coating, wherein the second coating includes a flaky pigment coated with a metal oxide, L based on the spectral reflectance of the reflected light R1 45 received at an angle of 45 degrees with respect to the specular reflected light from the incident light I1 45 incident on the surface of the first coating at an angle of 45 degrees, * C* Chroma C1 in the h color system * 45 and lightness L1 * 45 satisfy the relation that C1 * 45 ≤ 15 20 ≤ L1 * 45 ≤ 70 and the reflected light R1 that receives the incident light I1 at an angle of 15 degrees with respect to the specular reflection light 45 has L 15 based on the spectral reflectance of * C * and lightness L1 in the h color system * 15 and the reflected light R1 that receives the incident light I1 45 at an angle of 110 degrees with respect to the specular reflection light 110 has L * C * and lightness L1 in the h color system * 110 satisfy the relation that L1 * 15 - L1 * 110 ≤ 15 and the average light transmittance of the second coating film in the wavelength range of 400 nm to 700 nm is 50% or more, and the reflected light Rm that receives the incident light Im 45 incident at an angle of 45 degrees with respect to the surface of the multilayer coating film 15 at an angle of 15 degrees with respect to the specular reflection light * has L * C * and chroma Cm in the h color system 15 45 and the reflected light Rm that receives the incident light Im 45 at an angle of 45 degrees with respect to the specular reflection light * has L * C * and chroma Cm in the h color system 45 * satisfy the relation that Cm 15 * > 10 Cm* 15 -Cm * 45 >5 A multilayer coating film satisfying the following relationship. [2] Incident light I2 incident at an angle of 45 degrees with respect to the surface of a test coating film obtained by coating the second coating composition used for forming the second coating film on a black object 45 is the reflected light R2 received at an angle of 15 degrees with respect to the specular reflected light 15 Based on the spectral reflectance of * C * The chroma C2 in the h color system * 15 is C2 * 15 ≧5 The multilayer coating film of the above [1] satisfying the following relationship. [3] The content of the flaky pigment is 0.5% by mass or more and 20% by mass or less of the second coating film, and the multilayer coating film of the above [1] or [2]. [4] The second coating film further contains a coloring pigment, The content of the coloring pigment is 0.05% by mass or more and 1.5% by mass or less of the second coating film, and the multilayer coating film of any one of the above [1] to [3]. [5] The mass ratio of the flaky pigment to the coloring pigment is 2 or more and 400 or less, and the multilayer coating film of the above [4]. [6] An object to be coated and The above-mentioned multilayer coating film of any one of [1] to [5] disposed on the object to be coated, and a coated article having the same. [7] Forming a first coating film by coating a first coating composition on an object to be coated; Forming a second coating film by coating a second coating composition containing a flaky pigment coated with a metal oxide on the first coating film; Forming a clear coating film by coating a clear coating composition on the second coating film, and a method for manufacturing a coated article having a multilayer coating film, comprising: Incident light I1 incident at an angle of 45 degrees with respect to the surface of the first coating film45 The reflected light R1 received at an angle of 45 degrees with respect to the specularly reflected light 45 L based on the spectral reflectance of * C * The chroma C1 in the h color system * 45 and the lightness L1 * 45 satisfy the condition that C1 * 45 ≤ 15 20 ≤ L1 * 45 ≤ 70 and the incident light I1 45 The reflected light R1 received at an angle of 15 degrees with respect to the specularly reflected light 15 L based on the spectral reflectance of * C * The lightness L1 in the h color system * 15 and the incident light I1 45 The reflected light R1 received at an angle of 110 degrees with respect to the specularly reflected light 110 L based on the spectral reflectance of * C * The lightness L1 in the h color system * 110 satisfy the condition that L1 * 15 -L1 * 110 ≤ 15 and the average value of the light transmittance of the second coating film in the wavelength range of 400 nm to 700 nm is 50% or more, the 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 with respect to the specularly reflected light 15 L based on the spectral reflectance of * C * The 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 with respect to the specularly reflected light 45 L based on the spectral reflectance of * C * The chroma Cm in the h color system *45 is such that Cm * 15 > 10 Cm * 15 -Cm * 45 > 5 A method for manufacturing a painted article that satisfies the relationship of.

Industrial Applicability

[0195] The multilayer coating film of the present disclosure exhibits a steady gray color in the face area and a colored tint in the highlight area, so that a new design can be imparted to various objects to be coated.

Claims

1. 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, wherein the second coating film contains flaky pigments coated with a metal oxide, Incident light I1 incident at an angle of 45 degrees with respect to the surface of the first coating film ４５ is reflected light R1 received at an angle of 45 degrees with respect to the specularly reflected light ４５ L based on the spectral reflectance of ＊ C ＊ chroma C1 in the LCh color system ＊ ４５ and lightness L1 ＊ ４５ are C1 ＊ ４５ ≤15 20 ≤ L1 ＊ ４５ ≤ 70 satisfies the relationship of, the incident light I1 ４５ is the reflected light R1 received at an angle of 15 degrees with respect to the specularly reflected light １５ L based on the spectral reflectance of ＊ C ＊ the lightness L1 in the LCh color system ＊ １５ and the incident light I1 ４５ is the reflected light R1 received at an angle of 110 degrees with respect to the specularly reflected light １１０ L based on the spectral reflectance of ＊ C ＊ the lightness L1 in the LCh color system ＊ １１０ are such that L1 ＊ １５ -L1 ＊ １１０ ≤15 satisfies the relationship of, the average light transmittance of the second coating film at a wavelength of 400 nm to 700 nm is 50% or more, Incident light Im incident at an angle of 45 degrees with respect to the surface of the multilayer coating film ４５ is the reflected light Rm received at an angle of 15 degrees with respect to the specularly reflected light １５ Based on the spectral reflectance of ＊ C ＊ The chroma Cm in the LCh color system ＊ １５ And the incident light Im ４５ is the reflected light Rm received at an angle of 45 degrees with respect to the specularly reflected light ４５ Based on the spectral reflectance of ＊ C ＊ The chroma Cm in the LCh color system ＊ ４５ And are Cm ＊ １５ > 10 Cm ＊ １５ -Cm ＊ ４５ >5 A multilayer coating film that satisfies the relationship of.

2. The incident light I2 that is incident at an angle of 45 degrees with respect to the surface of a test coating film obtained by coating a second coating composition used for forming the second coating film on a black object to be coated ４５ is the reflected light R2 that is received at an angle of 15 degrees with respect to the specularly reflected light １５ The L based on the spectral reflectance of ＊ C ＊ The chroma C2 in the LCh color system ＊ １５ is C2 ＊ １５ ≥5 The multilayer coating film according to Claim 1, which satisfies the relationship of.

3. The multilayer coating film according to Claim 1 or 2, wherein the content of the flaky pigment is 0.5% by mass or more and 20% by mass or less of the second coating film.

4. The second coating film further contains a coloring pigment, The multilayer coating film according to Claim 1 or 2, wherein the content of the coloring pigment is 0.05% by mass or more and 1.5% by mass or less of the second coating film.

5. The multilayer coating film according to Claim 4, wherein the mass ratio of the flaky pigment to the coloring pigment is 2 or more and 400 or less.

6. A coated article having the coated article and the multilayer coating film according to Claim 1 disposed on the coated article.

7. A method for manufacturing 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, coating a first coating composition on a coated object to form the first coating film, coating a second coating composition containing flaky pigments coated with a metal oxide on the first coating film to form the second coating film, coating a clear coating composition on the second coating film to form the clear coating film, and Incident light I1 incident at an angle of 45 degrees with respect to the surface of the first coating film ４５ is the reflected light R1 received at an angle of 45 degrees with respect to the specular reflected light ４５ L based on the spectral reflectance of ＊ C ＊ the chroma C1 in the LCh color system ＊ ４５ and the lightness L1 ＊ ４５ are C1 ＊ ４５ ≤15 20 ≤ L1 ＊ ４５ ≤ 70 satisfies the relationship of, The incident light I1 ４５ is received at an angle of 15 degrees with respect to the specular reflection light, and the reflectance R1 １５ is based on the spectral reflectance of L ＊ C ＊ The lightness L1 in the h color system ＊ １５ and the incident light I1 ４５ is received at an angle of 110 degrees with respect to the specular reflection light, and the reflectance R1 １１０ is based on the spectral reflectance of L ＊ C ＊ The lightness L1 in the h color system ＊ １１０ and are L1 ＊ １５ -L1 ＊ １１０ ≤15 satisfies the relationship of, the average value of the light transmittance of the second coating film at a wavelength of 400 nm to 700 nm is 50% or more, Incident light Im incident at an angle of 45 degrees with respect to the surface of the multilayer coating ４５ is reflected light Rm received at an angle of 15 degrees with respect to the specularly reflected light １５ L based on the spectral reflectance of ＊ C ＊ chroma Cm in the LCh color system ＊ １５ and the incident light Im ４５ is reflected light Rm received at an angle of 45 degrees with respect to the specularly reflected light ４５ L based on the spectral reflectance of ＊ C ＊ chroma Cm in the LCh color system ＊ ４５ are such that Cm ＊ １５ > 10 Cm ＊ １５ -Cm ＊ ４５ >5 A method for manufacturing a coated article that satisfies the relationship of.

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