Stacked coating film and coated object

Abstract

To provide a laminated coating film that develops a red color by a brilliant layer and a coloring layer having light transmissivity, which achieves a metallic color having high designability while improving red color developability.SOLUTION: A laminated coating film 12 has a brilliant layer 14 containing a brilliant material 21 and a black pigment 23, and a coloring layer 15 that contains a red pigment 25 and has light transmissivity, in which inclination of a tangent at a spectral reflectance spectrum of 620 nm on absolute value display of the coloring layer 15 is 0.02 nm-1 or more and 0.06 nm-1 or less, which is obtained by dividing spectral reflectance measured at a light incident angle of 45° and a light-receiving angle of 15° in a state where the coloring layer 15 is laminated on the brilliant layer 14 by spectral reflectance measured at a light incident angle of 45° and a light-receiving angle of 15° in a state where the coloring layer 15 is removed and the brilliant layer surface is exposed .SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a laminated coating film including a colored layer (color clear layer) containing a pigment and having translucency on a luminous layer (metallic base layer) containing a luminous material, and an object coated with the laminated coating film.

Background Art

[0002] In recent years, for objects to be coated that require high design quality such as automobiles, it has been desired to obtain a paint color with high chroma of highlights and strong depth.

[0003] Patent Document 1 describes a laminated sheet for molding useful for automotive-related members and the like, and obtaining a design with a sense of depth. It is a laminated sheet in which a colored layer is stacked on a metallic gloss layer, and the lightness L of the transmitted light of the colored layer is set to 20 to 80, the gloss value of the metallic gloss layer is set to 200 or more, and the chroma C of the regular reflected light at 45 degrees is set to 150 or more. The same document also describes adding aluminum flakes to the metallic gloss layer and adopting perylene red as the pigment of the colored layer. * is set to 20 to 80, the gloss value of the metallic gloss layer is set to 200 or more, and the chroma C of the regular reflected light at 45 degrees * is set to 150 or more. The same document also describes adding aluminum flakes to the metallic gloss layer and adopting perylene red as the pigment of the colored layer.

[0004] Patent Document 2 describes a laminated coating film in which a luminous layer containing a luminous material formed directly or indirectly on the surface of an object to be coated and a colored layer containing a red pigment and having translucency and laminated on the luminous layer produce a red color. It is described that in the above laminated coating film, with respect to the Y value calibrated with a standard white plate in the XYZ color system for the luminous layer, when the incident angle of light is 45°, the Y value of the reflected light measured at a light receiving angle of 10° is denoted as Y(10°), and the Y value of the reflected light measured at a light receiving angle of 25° is denoted as Y(25°), Y(10°) is 50 or more and 950 or less, Y(25°)=k×Y(10°) (where k is a coefficient), k is 0.05 or more and 0.35 or less, and the spectral reflectance measured at an incident angle of light of 45° and a light receiving angle of 10° with the colored layer laminated on the luminous layer is divided by the spectral reflectance measured at an incident angle of light of 45° and a light receiving angle of 10° with the colored layer removed and the surface of the luminous layer exposed, and the slope of the tangent line at 620 nm of the spectral transmittance spectrum of the colored layer in absolute value representation is 0.012 nm -1 or more and 0.03 nm -1 or less.

[0005] Patent Document 3 describes a method for forming a multilayer coating film that can be applied to various industrial products, particularly the outer panels of automobiles, and provides a coating film with high brightness and high color saturation in highlights (near specular reflection light), high color saturation in shades (oblique directions), a large difference in lightness between highlights and shades, and a uniform finish design. In this method, a first color clear coating film is formed on a metallic base coating film obtained by coating a metallic base paint containing a coloring pigment and a scaly luminous pigment, and then a second color clear coating film is further formed thereon. The coloring pigments contained in the first and second color clear coating films are the same. Also, the concentration of the coloring pigment per unit film thickness in the first and second color clear coating films is in the range of 30 / 70 to 60 / 35 as the ratio of the former to the latter.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] When a metallic paint is applied to a vehicle body or the like, a metallic texture is obtained because of high flip-flop property (hereinafter referred to as "FF property") in which the lightness changes depending on the viewing angle of the painted object. That is, the higher the contrast between light (highlight) and dark (shadow), the higher the FF property and the better the metallic texture. However, when trying to achieve a highly designed metallic color, in addition to the strength of the contrast, it is important that the color of the coloring material vividly develops in the highlight.

[0008] An object of the present disclosure is to realize a highly designed metallic color while improving the red color development property in a laminated coating film in which red is developed by a light-emitting layer and a colored layer having translucency.

Means for Solving the Problems

[0009] In order to solve the above problems, the present disclosure focused on the relationship between the spectral transmittance characteristics of the colored layer and the reflection characteristics of the light-emitting layer.

[0010] The laminated coating film disclosed herein includes a light-emitting layer containing a light-emitting material and a black-based coloring material formed directly or indirectly on the surface of an object to be coated, and a colored layer containing a red-based coloring material and having translucency, which is stacked on the light-emitting layer. The above red coloring material is a red pigment. The above brightening layer contains, as the brightening material, aluminum flakes having an average particle diameter of 5 μm or more and 30 μm or less and an average thickness of 10 nm or more and 500 nm or less. The concentration of the aluminum flakes in the above brightening layer is 1% by mass or more and 17% by mass or less. The above black coloring material contained in the above brightening layer is carbon black, and the concentration of the carbon black in the above brightening layer is 1% by mass or more and 20% by mass or less. The spectral transmittance spectrum of the colored layer in absolute value representation obtained by dividing the spectral reflectance measured at a light incident angle of 45° and a light receiving angle of 15° with the colored layer laminated on the phosphorescent layer by the spectral reflectance measured at a light incident angle of 45° and a light receiving angle of 15° with the colored layer removed and the surface of the phosphorescent layer exposed has a tangent slope at 620 nm of 0.02 nm -1 or more and 0.06 nm -1 or less. It is characterized by the following.

[0011] In a laminated coating film formed by a phosphorescent layer and a colored layer having translucency to produce a red color, the reflected light from the phosphor contained in the phosphorescent layer passes through the colored layer, thereby vividly developing the colorant (pigment and / or dye) contained in the colored layer. The higher the brightness in the highlight and the lower the brightness in the shade, the more vivid the red color development in the highlight can be obtained, and sufficient darkness of the shade can be obtained, so the FF property is improved and a metallic color with high design quality can be realized.

[0012] Here, the inventors of the present application have found that the tangent slope at 620 nm of the spectral transmittance spectrum is in a proportional relationship with the chroma C * . The higher the chroma C * , the better the red color development. When the tangent slope is 0.02 nm -1 or more and 0.06 nm -1 or less, a sufficient chroma C * can be obtained, so a vivid red color development with less turbidity and high transparency can be obtained.

[0013] Note that the light receiving angle for measuring the spectral reflectance for obtaining the spectral transmittance spectrum of the colored layer is set to 15° at which the red hue clearly appears. In the case of a red colorant, since the spectral reflectance rises in the wavelength range of 590 nm to 650 nm, it is defined as the tangent slope of the spectrum at the median wavelength of 620 nm in that wavelength range. The tangent slope at 620 nm of the spectral transmittance spectrum is preferably 0.03 nm -1 or more and 0.06 nm -1 or less.

[0014] In addition, when the light diffusely reflected on the minute irregularities, edges, and substrate (e.g., an electrodeposited coating film) on the surface of the brightening material passes through the colored layer, the amount of light in the shade direction increases, and the brightness of the shade becomes higher. When the brightness of the shade increases, the whiteness of the shade increases, which causes the red color development in the highlight to become blurred.

[0015] In this configuration, since the brightening layer contains a black-based coloring material, in the brightening layer, most of the incident light passing through the gaps between the brightening materials is absorbed and / or shielded by the black-based coloring material, so that almost no light is reflected by the substrate. In addition, since the light diffusely reflected by the minute irregularities and edges on the surface of the brightening material is absorbed and / or shielded by the black-based coloring material, the brightness of the shade decreases.

[0016] According to this configuration, the spectral transmittance characteristics of the colored layer and the reflection characteristics of the brightening layer work together, so that in the highlight, red vividly develops brightly with a sense of transparency, and on the shade side, the brightness drops, making the red in the highlight stand out even more. Thus, it is advantageous for realizing a highly designed metallic color.

[0017] Examples of the red-based coloring material for the colored layer include red-based pigments with excellent weather resistance and / or red-based dyes with excellent transparency. From the viewpoint of ensuring sufficient weather resistance of the laminated coating film, preferably a red-based pigment can be employed.

[0018] As the red-based pigment, organic pigments such as perylene red, dibromoanthrasone red, azo red, anthraquinone red, quinacridone red, and diketopyrrolopyrrole can be preferably used.

[0019] In this configuration , the red-based coloring material is a red-based pigment, Preferably, The average particle size of the red-based pigment is 2 nm or more and 160 nm or less.

[0020] Since the average particle diameter of the red pigment particles (in this specification, the "average particle diameter of the pigment particles" may be referred to as the "pigment particle diameter") is 160 nm or less, there is no geometric optical scattering or Mie scattering by the pigment particles, and since it is 2 nm or more, Rayleigh scattering is also avoided, which is advantageous for a transparent and vivid red color development. Also, due to the small pigment particle diameter, at the same pigment concentration, compared to the case where the pigment particle diameter is large, when light passes through the colored layer, the frequency of hitting and being absorbed by the pigment particles is higher, and thus the attenuation of light becomes larger. When the attenuation of light becomes larger, the amount of light passing through the colored layer decreases and the lightness decreases. However, since the amount of light in the highlight direction is originally large, the influence of the attenuation of light on the lightness is small. On the other hand, since the amount of light in the shade direction is originally small, the influence of the attenuation of light on the lightness becomes large. Thus, by reducing the diameter of the above-mentioned pigment particles, a higher FI can be achieved, which is advantageous for obtaining a high metallic texture. The average particle diameter of the red pigment is more preferably 2 nm or more and 30 nm or less.

[0021] Note that FI is the Flop Index, which is a metallic feeling index of X-Rite.

[0022] In this configuration The above-mentioned brightening layer contains, as the above-mentioned brightening material, aluminum flakes having an average particle diameter of 5 μm or more and 30 μm or less and an average thickness of 10 nm or more and 500 nm or less, and the concentration of the aluminum flakes in the above-mentioned brightening layer is 1 mass% or more and 17 mass% or less.

[0023] Since such aluminum flakes have a visible light reflectance of about 90% or more, it is possible to sufficiently secure the amount of light in the highlight direction and obtain sufficient lightness of the highlight. In particular, the diffused reflection at the edge of the aluminum flakes becomes stronger as the thickness of the flakes is thicker. By making the thickness of the aluminum flakes thinner as described above, the intensity of the diffused reflection can be weakened. Thus, the lightness of the shade can be reduced.

[0024] Also, when the concentration of aluminum flakes is less than 1% by mass, the amount of reflected light by the aluminum flakes is insufficient, and sufficient brightness of the highlights cannot be obtained. When the concentration of aluminum flakes exceeds 17% by mass, the influence of diffuse reflection due to the fine irregularities and edges on the surface of the aluminum flakes becomes large, and the lightness of the shade becomes too high. By setting the concentration of the aluminum flakes within the above range, high FI can be achieved while ensuring sufficient darkness of the shade. The concentration of the above aluminum flakes is preferably 5% by mass or more and 12% by mass or less.

[0025] Preferably, the surface roughness Ra of the above aluminum flakes is 50 nm or less.

[0026] Diffuse reflection due to fine irregularities on the surface of aluminum flakes causes an increase in the lightness of the shade. By setting the surface roughness Ra of the aluminum flakes within the above range, diffuse reflection can be reduced, and thus the lightness of the shade can be reduced.

[0027] Preferably, the concentration of the red coloring material in the above coloring layer is 1% by mass or more and 17% by mass or less.

[0028] The transmission characteristics of the coloring layer vary depending on the concentration of the coloring material in the coloring layer. When the concentration of the red coloring material in the coloring layer is low, the color development property of the red hue becomes insufficient. Also, when the concentration of the coloring material is low, the reflected light from the light-emitting layer, especially the light due to diffuse reflection, is not attenuated much when passing through the coloring layer, and the lightness of the shade increases, so the FI value decreases. On the other hand, when the concentration of the coloring material becomes 1% by mass or more, sufficient color development property of the red hue can be ensured, and the light due to diffuse reflection is sufficiently absorbed by the coloring material when passing through the coloring layer, so the lightness of the shade decreases and the FI value increases. On the other hand, when the concentration of the coloring material becomes excessively high, the effect of the coloring material absorbing and / or shielding the reflected light from the light-emitting layer becomes large and the brightness of the highlights decreases, so the FI value decreases. Also, when the coloring material is a pigment, light scattering by the pigment particles also causes an increase in the lightness of the shade and thus a decrease in the FI value, so the upper limit of the coloring material concentration is preferably 17% by mass.

[0029] The concentration of the red coloring material is preferably 4% by mass or more and 10% by mass or less, more preferably 5% by mass or more and 9% by mass or less, and particularly preferably 5% by mass or more and 7% by mass or less.

[0030] Preferably, the coloring layer further contains a black coloring material.

[0031] According to this configuration, when the reflected light from the brightening material in the brightening layer passes through the coloring layer, the reflected light is absorbed by the black coloring material over the entire wavelength range. Since the amount of light in the shade direction is small, when absorbed by the black coloring material, the amount of reflected light passing through the coloring layer is greatly reduced. On the other hand, since the amount of reflected light in the highlight is large, even if a part of it is absorbed by the black coloring material, the amount of reflected light passing through the coloring layer is sufficiently ensured. Thus, the coated article provided with the laminated coating film appears pitch black in the shade, while the red color appears vivid in the highlight, and a more highly designed metallic color is achieved.

[0032] Preferably, the concentration of the black coloring material in the coloring layer is 6% by mass or less.

[0033] If the concentration of the black coloring material becomes too high, the amount of absorbed reflected light increases, so the blackness in the highlight excessively increases, and turbidity occurs in the red color development in the highlight. According to this configuration, by setting the concentration of the black coloring material within the above range, an excessive increase in blackness in the highlight can be suppressed, and turbidity in the red color development can be suppressed. Thus, a vivid red color development in the highlight can be obtained.

[0034] Preferably, the ratio of the black coloring material to the total of the red coloring material and the black coloring material in the coloring layer is 26% by mass or less.

[0035] Even when the ratio of the black coloring material in the coloring material increases too much, the blackness in the highlight excessively increases, which causes turbidity in the red color development in the highlight. According to this configuration, since an excessive increase in blackness in the highlight can be suppressed and turbidity in the red color development can be suppressed, it is advantageous for obtaining a vivid red color development in the highlight.

[0036] Examples of the black coloring material contained in the bright layer include black pigments with excellent weather resistance and / or black dyes with excellent transparency. From the viewpoint of ensuring sufficient weather resistance of the laminated coating film, a black pigment can be adopted. As the black pigment, for example, carbon black, chromium oxide, iron oxide, manganese oxide, black indigo pigment, etc. can be used.

[0037] In this configuration, When the black coloring material contained in the bright layer is carbon black ri the concentration of the carbon black in the bright layer is 1% by mass or more and 20% by mass or less. ru.

[0038] If the concentration of carbon black is too low, there is a risk that its light absorption function and hiding power cannot be sufficiently obtained. On the other hand, if the concentration of carbon black is too high, the structure formed by the aggregation of primary particles is likely to be mechanically entangled, increasing light scattering, resulting in a decrease in transparency and an increase in the lightness of the shade. Therefore, setting the concentration of carbon black in the bright layer within the above range is advantageous for reducing the lightness of the shade.

[0039] The average particle size of the carbon black is preferably 200 nm or less.

[0040] According to this configuration, since the average particle size of carbon black is 1 / 2 wavelength or less of the lower limit of visible light (wavelength 400 nm), light scattering by carbon black particles can be suppressed.

[0041] The bright layer may contain a coloring material other than the black coloring material, for example, a red coloring material, as a coloring material. Thereby, light scattering is suppressed. From the viewpoint of increasing the FI value, it is desirable to contain only the black coloring material as the coloring material.

[0042] Examples of the coated object provided with the above-described laminated coating film include, for example, an automobile body, and may also be a body of a motorcycle or other vehicle, or other metal products or plastic products.

[0043] Further, the laminated coating film and the coated object of the present disclosure may have the following configurations.

[0044] Regarding the Y value calibrated with a standard white plate in the XYZ color system of the above-described bright layer, when the incident angle of light (the angle from the perpendicular to the surface of the bright layer) is 45°, and the Y value of the reflected light measured at a light receiving angle (the inclination angle from the specular reflection direction to the light source side) of 5° is defined as Y(5°), and the Y value of the reflected light measured at a light receiving angle of 15° is defined as Y(15°), Y(5°) is 30 or more and 700 or less, and Y(15°)=k×Y(5°) (where k is a coefficient), and it is preferable that k is 0.01 or more and 0.3 or less.

[0045] Here, the Y value in the XYZ color system is a stimulus value representing brightness (visual reflectance). Y(5°) is an index of the luminance sense of the highlight. Y(15°) is an index as to whether or not the hue due to the red-based colorant clearly appears at an observation angle slightly deviated from the highlight direction. When Y(5°) is 30 or more and 700 or less, and k in Y(15°)=k×Y(5°) is 0.01 or more and 0.3 or less, the colorant of the colored layer is vividly colored by the reflected light from the bright layer, the hue due to the colorant clearly appears, and the FF property also becomes high.

[0046] Note that Y(5°) is preferably 150 or more and 500 or less, more preferably 200 or more and 400 or less, and particularly preferably 200 or more and 300 or less. Also, k is preferably 0.03 or more and 0.2 or less, more preferably 0.05 or more and 0.15 or less.

[0047] Regarding the above-described bright layer, the lightness index L of the reflected light measured at a light receiving angle (the inclination angle from the specular reflection direction to the light source side) θ with the incident angle of light (the angle from the perpendicular to the surface of the bright layer) being 45° * value is L *When it is L(θ), it is preferable that L(θ) is 10 or less at 45° ≤ θ ≤ 80° and 100° ≤ θ ≤ 110°. * It is preferably 10 or less.

[0048] By making the lightness in the shade direction (45° ≤ θ ≤ 80° and 100° ≤ θ ≤ 110°) 10 or less, sufficient shade darkness can be ensured. Note that the above L(θ) at 45° ≤ θ ≤ 80° and 100° ≤ θ ≤ 110° * is preferably 5 or less. In particular, the above L(θ) at 45° ≤ θ ≤ 80° and 100° ≤ θ ≤ 110° * is preferably 10 or less when the light-emitting layer contains a black-based colorant and a red-based colorant, and is preferably 5 or less when the light-emitting layer contains only a black-based colorant.

[0049] When the above light-emitting material is projected onto the bottom surface of the above light-emitting layer, it is preferable that the ratio of the projected area of the above light-emitting material occupying the bottom surface is 3% or more and 70% or less per unit area.

[0050] If the ratio of the projected area of the light-emitting material is less than the lower limit value, the amount of reflected light by the light-emitting material is insufficient, and sufficient lightness of the highlight cannot be obtained. On the other hand, when the ratio of the projected area of the light-emitting material exceeds the upper limit value, since the amount of the light-emitting material contained in the light-emitting layer is large, the influence of diffuse reflection due to the fine unevenness and edges on the surface of the light-emitting material becomes large, and the lightness of the shade becomes too high. By setting the ratio of the projected area of the light-emitting material within the above range, high FI can be achieved while ensuring sufficient shade darkness. Note that the ratio of the above area of the light-emitting material is preferably 20% or more and 50% or less per unit area.

[0051] The above light-emitting layer preferably has a spectral reflectance with respect to a standard white plate in the wavelength range of 450 nm to 700 nm measured at a light incident angle of 45° and light receiving angles of 45° and 110° of 0.02 or less in absolute value display.

[0052] As a result, sufficient darkness of the shade can be obtained. In particular, the spectral reflectance is preferably 0.02 or less when the light-emitting layer contains a black-based colorant and a red-based colorant, and preferably 0.01 or less when the light-emitting layer contains only a black-based colorant.

[0053] It is preferable that a transparent clear layer is directly laminated on the light-emitting layer. Acid resistance and scratch resistance can be obtained by the transparent clear layer.

Advantages of the Invention

[0054] According to the present disclosure, in a laminated coating film in which a red color is produced by a light-emitting layer and a colored layer having translucency, when the slope of the tangent line is 0.02 nm -1 or more and 0.06 nm -1 or less, sufficient chroma C * is obtained, so that a vivid red color development with little turbidity and high transparency can be obtained. Further, since the light-emitting layer contains a black-based colorant, the light diffusely reflected by the fine irregularities and edges on the surface of the light-emitting material is shielded and / or absorbed by the black-based colorant, and the lightness of the shade is reduced. Thus, the spectral transmittance characteristics of the colored layer and the reflection characteristics of the light-emitting layer cooperate with each other, and in the highlight, red is brightly developed with a transparent feeling, and the lightness drops on the shade side, so that the red color in the highlight becomes more prominent, which is advantageous for realizing a highly decorative metallic color.

Brief Description of the Drawings

[0055]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Mode for Carrying Out the Invention

[0056] Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. The following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0057] <Configuration Example of Multilayer Coating Film> As shown in FIG. 1, the vehicle body 11 (coated object) of the present embodiment of an automobile includes a multilayer coating film 12 provided on the surface of a steel sheet 11A (object to be coated) via an electrodeposition coating film 13. The multilayer coating film 12 is formed by sequentially laminating a brightening layer 14, a colored layer 15 having translucency, and a transparent clear layer 16. The electrodeposition coating film 13 is formed on the surface of the steel sheet 11A by cationic electrodeposition coating in advance.

[0058] The brightening layer 14 contains a resin component as a base material, a brightening material 21, and a first black pigment 23 as a black coloring material. The colored layer 15 contains a resin component as a base material, a red pigment 25 as a red coloring material, and a second black pigment 27 as a black coloring material.

[0059] As the resin components of the brightening layer 14 and the coloring layer 15, although not intended to be limiting, for example, acrylic resins, polyester resins, urethane resins, melamine resins, etc. can be adopted alone or in combination of multiple types. As the resin component of the transparent clear layer 16, for example, a carboxylic acid group-containing acrylic resin, a combination of a polyester resin and an epoxy-containing acrylic resin, a combination of an acrylic resin and / or a polyester resin and a polyisocyanate, etc. can be adopted.

[0060] The brightening layer 14 and the coloring layer 15 may contain additives such as an ultraviolet ray shielding material, a tackifier, a thickening agent, a pigment dispersant, a surface conditioner, etc. as necessary. In particular, from the viewpoint of the light resistance of the laminated coating film 12, it is desirable to contain an ultraviolet ray shielding material. As the ultraviolet ray shielding material, an organic compound-based ultraviolet absorber, an inorganic compound-based ultraviolet scattering agent, etc. can be adopted, and among them, it is preferable to adopt nanoparticles of metal oxides such as iron oxide.

[0061] The film thickness of the brightening layer 14 is preferably 6 μm or more and 15 μm or less, more preferably 7 μm or more and 13 μm or less, and the film thickness of the coloring layer 15 is preferably 8 μm or more and 15 μm or less.

[0062] The surface roughness Ra of the electrodeposited coating film 13 is preferably 2.0 μm or less, more preferably 1.0 μm or less. Thereby, the orientation of the brightening material 21 in the brightening layer 14 is improved.

[0063] <Brightening layer> [Brightening material] As the brightening material 21 contained in the brightening layer 14, metal flakes etc. with a high visible light reflectance can be adopted. In this embodiment, aluminum flakes are adopted as the brightening material 21.

[0064] From the viewpoint of obtaining sufficient brightness of the highlight, the visible light reflectance of the aluminum flakes is preferably 90% or more. Thereby, a sufficient amount of light in the highlight direction can be ensured, and sufficient brightness of the highlight can be obtained.

[0065] As such aluminum flakes, specifically, those having an average particle size of 5 μm or more and 30 μm or less, preferably 10 μm or more and 15 μm or less, and an average thickness of 10 nm or more and 500 nm or less are preferably employed. In particular, the average thickness is preferably 10 nm or more and 50 nm or less in the case of vapor-deposited aluminum flakes, and 100 nm or more and 500 nm or less in the case of thin-film aluminum flakes.

[0066] In this specification, the average particle size of the brightening material 21 and various coloring pigments is obtained by determining D50, which is the 50% value of the particle size distribution measured by, for example, a laser diffraction particle size distribution measuring device.

[0067] The average thickness of the brightening material 21 is obtained, for example, by observing with a scanning electron microscope, measuring the thicknesses of a plurality (for example, 50) of brightening materials 21, and calculating the average value thereof.

[0068] If the average particle size is too small, the reflection characteristics may deteriorate. If the average particle size is too large, although the reflection characteristics are excellent, the particle feeling of the appearance may become too strong. Further, the diffuse reflection at the edge of the aluminum flake becomes stronger as the thickness of the flake is thicker. As described above, since the thickness is thin, the diffuse reflection is weak. Therefore, it is advantageous for reducing the lightness of the shade.

[0069] Note that the aspect ratio (average particle size / average thickness) of the aluminum flake is preferably 30 or more and 300 or less.

[0070] Also, the aluminum flake preferably has a surface roughness Ra of 50 nm or less. In particular, in the case of vapor-deposited aluminum flakes, the surface roughness Ra is preferably 7 nm or less, and in the case of smooth aluminum flakes, the surface roughness Ra is preferably 50 nm or less. Thereby, the diffuse reflection due to the fine unevenness on the aluminum flake surface can be reduced, and thus the lightness of the shade can be reduced.

[0071] Note that the brightening material 21 is oriented so as to be substantially parallel to the surface of the brightening layer 14 (so that the average orientation angle of the brightening material 21 with respect to the surface of the brightening layer 14 is 1.2 degrees or less) in order to enhance the brightness of the highlight. For example, after applying a paint containing the brightening material 21, the first black pigment 23, etc. onto the electrodeposition coating film 13, the brightening material 21 is arranged so that the average orientation angle is 1.2 degrees or less by utilizing the fact that the coating film shrinks in volume and becomes thinner due to evaporation of the solvent during baking. The average orientation angle of the brightening material 21 is obtained by calculating the inclination of the brightening material 21 with respect to the surface of the brightening layer 14 in a plurality (for example, 50) of brightening materials 21 included in one field of view from the 3D shape data (xyz coordinates) of the surface of the brightening layer 14 measured using a laser microscope (manufactured by Keyence Corporation, VK-X1000), and averaging them.

[0072] There are two types of aluminum flakes: the leafing type and the non-leafing type, and either type may be used, but it is preferable to use the non-leafing type of aluminum flakes.

[0073] In the case of leafing type aluminum flakes, since the surface tension is low, when a paint containing leafing type aluminum flakes is applied, the aluminum flakes float on the surface of the brightening layer 14 and are oriented parallel to the surface. When the aluminum flakes float on the surface of the brightening layer 14, the amount of reflected light increases and the FF property is enhanced, but a planar strong gloss like specular reflection can be obtained. Also, in the case of leafing type aluminum flakes, there are problems such as a decrease in the adhesion between the brightening layer 14 and the coloring layer 15 due to a small surface area and a decrease in the amount of the resin component disposed on the surface of the brightening layer 14, and being easily peeled off by external factors such as chipping.

[0074] On the other hand, since non-leafing aluminum flakes have a high surface tension, when a paint containing non-leafing aluminum flakes is applied, as shown in FIG. 1 for example, the aluminum flakes are oriented parallel to the surface of the brightening layer 14 and are irregularly dispersed in the film thickness direction. As a result, the amount of reflected light changes corresponding to the position of the aluminum flakes in the film thickness direction, so that a three-dimensional metallic luster can be obtained, and a more design-oriented metallic color can be obtained. Further, in the case of non-leafing aluminum flakes, since a sufficient amount of the resin component disposed on the surface of the brightening layer 14 can be ensured, sufficient adhesion between the brightening layer 14 and the coloring layer 15 can be ensured.

[0075] [Area ratio of brightening material] The ratio of the projected area of the brightening material 21 on the bottom surface of the brightening layer 14 when the brightening material 21 is projected onto the bottom surface (also referred to as "area ratio" in this specification) is preferably 3% or more and 70% or less, more preferably 20% or more and 50% or less per unit area.

[0076] If the area ratio of the brightening material 21 is too small, the amount of reflected light by the brightening material 21 is insufficient, and sufficient brightness of the highlight cannot be obtained. On the other hand, if the area ratio of the brightening material 21 is too large, since the amount of the brightening material 21 is large, the influence of diffuse reflection due to fine irregularities and edges on the surface of the brightening material 21 becomes large, the brightness of the shade increases, and the strength and weather resistance of the brightening layer 14 decrease. By setting the area ratio of the brightening material 21 within the above range, it is possible to achieve high FI while ensuring sufficient darkness of the shade, and to obtain sufficient strength and weather resistance.

[0077] The area ratio per unit area of the aluminum flakes can be obtained, for example, by magnifying and observing the brightening layer 14 from its surface with a microscope, calculating the area ratios of the aluminum flakes in a plurality of visual fields (for example, 10 visual fields) by image processing, and averaging them.

[0078] Specifically, FIG. 2 is a photograph of the light-emitting layer according to Production Example 1 shown in Table 1 taken from its surface side. In Production Example 1, aluminum flakes are used as the light-emitting material 21, carbon black is used as the first black pigment 23, and an acrylic resin, a urethane resin, and a melamine resin are used as the resin components. A coated plate is formed by forming only the light-emitting layer 14 on the surface of the steel plate 11A via an electrodeposition coating film 13.

[0079]

Table 1

[0080] The whiteish particles in FIG. 2 are aluminum flakes. From the figure, when the aluminum flakes are projected onto the bottom surface of the light-emitting layer 14, the area ratio of the aluminum flakes occupying the bottom surface can be calculated to be 22.5% per unit area.

[0081] The area ratio of the light-emitting material 21 as described above can be achieved, for example, by setting the concentration of the light-emitting material 21 in the light-emitting layer 14 to preferably 1% by mass or more and 17% by mass or less, more preferably 5% by mass or more and 12% by mass or less. If the concentration of the light-emitting material 21 is less than 1% by mass, a sufficient area ratio of the light-emitting material 21 cannot be obtained. If the concentration of the light-emitting material 21 exceeds 17% by mass, the area ratio of the light-emitting material 21 becomes too large.

[0082] [First black pigment] Although the flaky light-emitting material 21 is effective in increasing the brightness of the highlight, there is diffuse reflection due to minute irregularities on the surface of the flakes and diffuse reflection at the edges of the flakes. Further, there is diffuse reflection in the base (the electrodeposition coating film 13 in this embodiment). When the light diffusely reflected in this way passes through the colored layer 15, the amount of light in the shade direction increases and the brightness of the shade increases. When the brightness of the shade increases, the whiteness of the shade increases, which causes the red color development in the highlight to be blurred and the vividness to decrease. Therefore, it is desirable to contain the first black pigment 23 as a black coloring material in the light-emitting layer 14 and adjust the reflection characteristics of the shade by utilizing the light absorption function and hiding ability of the first black pigment 23.

[0083] Since most of the incident light passing through the gaps between the brilliance materials 21 is absorbed and / or shielded by the first black pigment 23, there is almost no diffuse reflection by the base (electro-deposition coating film 13). Then, the light diffusely reflected by the fine unevenness and edges of the brilliance material 21 is absorbed and / or shielded by the first black pigment 23, resulting in a decrease in the lightness of the shade.

[0084] As the first black pigment 23 contained in the brilliance layer 14, although not intended to be limiting, for example, carbon black with excellent weather resistance can be adopted. The concentration of the first black pigment 23 in the brilliance layer 14 is desirably 1% by mass or more and 20% by mass or less. If the concentration of carbon black is too low, there is a risk that its light absorption function and hiding power cannot be sufficiently obtained. On the other hand, if the concentration of carbon black is too high, the structures formed by the aggregation of primary particles are likely to be mechanically intertwined, increasing light scattering, so the transparency decreases and the lightness of the shade may increase. Therefore, setting the concentration of carbon black in the brilliance layer 14 within the above range is advantageous for reducing the lightness of the shade.

[0085] The average particle size of carbon black is preferably 200 nm or less. Since the average particle size of carbon black is 1 / 2 wavelength or less of the lower limit of visible light (wavelength 400 nm), light scattering by the carbon black particles can be suppressed. Thus, an increase in the lightness of the shade can be suppressed.

[0086] The brilliance layer 14 may contain a colorant of a color other than black, for example, a red colorant. Thereby, light scattering can be suppressed. From the viewpoint of increasing the FI, it is desirable to contain only a black colorant as the colorant.

[0087] Also, for adjusting the light reflection characteristics, a black or other dark base layer (absorbing layer) that absorbs light may be provided between the brilliance layer 14 and the electro-deposition coating film 13. That is, it is a method of absorbing the light transmitted through the gaps between the brilliance materials 21 in the brilliance layer 14 with the dark base layer. In the case of this method, painting of the dark base layer is required, but it is possible to adjust the reflection characteristics.

[0088] <Reflectance characteristics of the bright layer> [Y value] The Y value in the XYZ colorimetric system is Y among the tristimulus values X, Y, and Z defined by the following formula in the CIE XYZ color space (https: / / ja.wikipedia.org / wiki / CIE_1931_%E8%89%B2%E7%A9%BA%E9%96%93), and it is a stimulus value representing brightness (visual reflectance).

[0089] [Number]

[0090] Note that x(λ), y(λ), and z(λ) (the superscript bar notation is omitted for each) are CIE color-matching functions, and Le, Ω, λ are the spectral radiance of color for the colorimetric observer.

[0091] Figure 3 shows the method for measuring the Y value of the bright layer 14. The incident angle of the light source 41 with respect to the bright layer 14 is 45° (the inclination angle from the perpendicular to the surface of the bright layer 14). The light-receiving angle θ (the inclination angle from the specular reflection direction toward the light source side) by the sensor 42 sets the specular reflection direction as 0°. For the measurement, a three-dimensional variable-angle spectroscopic colorimetric system GCMS-4 manufactured by Murakami Color Research Laboratory Co., Ltd. was used.

[0092] In this embodiment, in order to increase the FI value, the reflection intensity Y(5°) at a light-receiving angle of 5° and the reduction rate k of the reflection intensity when the light-receiving angle changes from 5° to 15° are set to be within a predetermined range.

[0093] The reflection intensity Y(5°) at a light-receiving angle of 5° serves as an index for the luminance feeling of the highlight. Also, the reflection intensity Y(15°) at a light-receiving angle of 15° serves as an index for whether the hue by the red pigment 25 clearly appears at an observation angle slightly deviated from the highlight direction. The above reduction rate k is represented by the coefficient k in Y(15°) = k × Y(5°).

[0094] Y(5°) of the light-emitting layer 14 is 30 or more and 700 or less, preferably 150 or more and 500 or less, more preferably 200 or more and 400 or less, and particularly preferably 200 or more and 300 or less. And the coefficient k is 0.01 or more and 0.3 or less, preferably 0.03 or more and 0.2 or less, more preferably 0.05 or more and 0.15 or less. By setting the reflection characteristics of the light-emitting layer 14 in this way, the red pigment 25 of the colored layer 15 can be vividly colored by the reflected light from the light-emitting layer 14. Thus, the hue due to the red pigment 25 clearly appears and the FF property also increases.

[0095] Specifically, FIG. 4 shows the relationship between the Y value calibrated with a standard white plate in the XYZ colorimetric system of the light-emitting layer 14 (Table 1) of the above-described Production Example 1 and the light-receiving angle. When the Y value of the reflected light measured at a light-receiving angle of 5° is Y(5°) and the Y value of the reflected light measured at a light-receiving angle of 15° is Y(15°), in the example of FIG. 4, Y(5°) = 236 and Y(15°) = 13.1.

[0096] [L * value] L * value is the * a * b * lightness index of the colorimetric system. The L * value can be measured by the same method as the Y value.

[0097] As shown in FIG. 3, for the light-emitting layer 14, with the light incident angle being 45°, the lightness index L * value of the reflected light measured at the light-receiving angle θ is L * (θ). At this time, in the present embodiment, L * (θ) at 45° ≤ θ ≤ 80° and 100° ≤ θ ≤ 110° is 10 or less, preferably 5 or less. Note that since the reflected light overlaps with the incident light at a light-receiving angle of 90°, measurement is difficult. Therefore, measurement is not performed in the region of 80° < θ < 100°. By setting the lightness in the shade direction (45° ≤ θ ≤ 80° and 100° ≤ θ ≤ 110°) to 10 or less, preferably 5 or less, sufficient shade darkness can be ensured.

[0098] Specifically, FIG. 5 is a graph showing the relationship between the L value of the phosphorescent layer 14 of Production Example 1 and the light-receiving angle θ. As shown in FIG. 5, when the light-receiving angle is 45° ≤ θ ≤ 80° and 100° ≤ θ ≤ 110°, the L value is 5 or less. * When the light-receiving angle is 45° ≤ θ ≤ 80° and 100° ≤ θ ≤ 110°, the L value is 5 or less. * Specifically, FIG. 5 is a graph showing the relationship between the L value of the phosphorescent layer 14 of Production Example 1 and the light-receiving angle θ. As shown in FIG. 5, when the light-receiving angle is 45° ≤ θ ≤ 80° and 100° ≤ θ ≤ 110°, the L value is 5 or less.

[0099] In addition, the above L(θ) at 45° ≤ θ ≤ 80° and 100° ≤ θ ≤ 110° only needs to satisfy the condition of being 10 or less when the phosphorescent layer 14 contains a red colorant in addition to the first black pigment 23. * (θ) only needs to satisfy the condition of being 10 or less when the phosphorescent layer 14 contains a red colorant in addition to the first black pigment 23.

[0100] [Spectral reflectance] The spectral reflectance indicates the wavelength dependence of the reflectance. The spectral reflectance of the phosphorescent layer 14 can be measured by the same method as the Y value and the L value. * The spectral reflectance of the phosphorescent layer 14 can be measured by the same method as the Y value and the L value.

[0101] In this embodiment, for the phosphorescent layer 14, the spectral reflectance with respect to the standard white plate in the wavelength range of 450 nm to 700 nm measured with the light incident angle being 45° and the light-receiving angle θ being 45° and 110° (representative shade directions) is expressed as an absolute value and is 0.02 or less, preferably 0.01 or less.

[0102] Specifically, FIG. 6 is a graph showing the relationship between the above spectral reflectance of the phosphorescent layer 14 of Production Example 1 and the wavelength. As shown in FIG. 6, at the light-receiving angles of 45° and 110°, the spectral reflectance in the wavelength range of 450 nm to 700 nm is 0.01 or less. Thereby, sufficient darkness of the shade can be obtained.

[0103] In addition, the above spectral reflectance only needs to be 0.02 or less when the phosphorescent layer 14 contains a red colorant in addition to the first black pigment 23.

[0104] [Coloring layer] [Red pigment] As the red pigment 25, for example, organic pigments such as perylene red, dibromoanthrasone red, azo red, anthraquinone red, quinacridone red, diketopyrrolopyrrole can be used, and it is particularly preferable to use perylene red which is excellent in weather resistance.

[0105] Details will be described later, but the average particle size of the red pigment 25 is preferably 2 nm or more and 160 nm or less, more preferably 2 nm or more and 30 nm or less.

[0106] Since the average particle size of the red pigment is 160 nm or less, there is no geometric optical scattering or Mie scattering by the pigment particles, and since it is 2 nm or more, Rayleigh scattering is also avoided, which is advantageous for a clear and vivid red color with a sense of transparency. Also, due to the small average particle size, at the same pigment concentration, compared to the case where the pigment particle size is large, when light passes through the colored layer, the frequency of hitting and being absorbed by the pigment particles is higher, and thus the attenuation of light becomes larger. When the attenuation of light becomes larger, the amount of light passing through the colored layer 15 decreases, and the overall lightness decreases. However, since the amount of light in the highlight direction is originally large, the influence of light attenuation on lightness is small. On the other hand, since the amount of light in the shade direction is originally small, the influence of light attenuation on lightness becomes large. Thus, by reducing the diameter of the pigment particles, high FI can be achieved, which is advantageous for obtaining a high metallic texture.

[0107] The concentration of the red pigment 25 in the colored layer 15 is 1% by mass or more and 17% by mass or less, preferably 4% by mass or more and 10% by mass or less, more preferably 5% by mass or more and 9% by mass or less, and particularly preferably 5% by mass or more and 7% by mass or less.

[0108] When the concentration of the red pigment 25 in the colored layer 15 is less than 1% by mass, sufficient color development of red in the highlight cannot be obtained. Also, when the concentration of the red pigment 25 exceeds 17% by mass, the absorption and / or shielding effect of the reflected light by the pigment particles becomes large, the lightness of the highlight decreases, and due to the light scattering effect by the pigment particles, the lightness of the shade increases, so the FI value decreases.

[0109] [Second black pigment] Since the colored layer 15 contains the second black pigment 27, when the reflected light from the light-emitting material 21 of the light-emitting layer 14 passes through the colored layer 15, the reflected light is absorbed by the second black pigment 27 over the entire wavelength range. Since the shade direction has less light quantity, when absorbed by the second black pigment 27, the light quantity of the reflected light passing through the colored layer 15 is greatly reduced. On the other hand, since the reflected light of the highlight has a large light quantity, even if a part of it is absorbed by the second black pigment 27, the light quantity of the reflected light passing through the colored layer 15 is sufficiently ensured. Thus, the vehicle body 11 provided with the laminated coating film 12 appears jet black in the shade, while the red color appears vivid in the highlight, achieving a more highly designed metallic color.

[0110] As the second black pigment 27, although not intended to be limiting, for example, carbon black having excellent weather resistance can be adopted.

[0111] The average particle size of the carbon black is preferably 20 nm or more and 160 nm or less. Since the average particle size of the carbon black is equal to or less than 1 / 2 wavelength of the lower limit of visible light (wavelength 400 nm), light scattering by the carbon black particles can be suppressed.

[0112] The concentration of the second black pigment 27 in the colored layer 15 is preferably 6% by mass or less. Further, the ratio of the second black pigment 27 to the total of the red pigment 25 and the second black pigment 27 in the colored layer 15 is preferably 26% by mass or less.

[0113] If the concentration of the second black pigment 27 and / or the ratio of the second black pigment 27 in the coloring material becomes too high, the absorption amount of the reflected light increases, so the blackness of the highlight excessively increases and the red color development in the highlight becomes cloudy. By setting the concentration of the second black pigment 27 and / or the ratio of the second black pigment 27 in the coloring material within the above range, an excessive increase in blackness in the highlight can be suppressed and cloudiness of red color development can be suppressed. Thus, vivid red color development in the highlight can be obtained.

[0114] [Entire coloring material] The total amount of all colorants contained in the coloring layer 15, that is, the total of the red pigment 25 and the optional second black pigment 27, is preferably 1% by mass or more and 23% by mass or less.

[0115] The transmission characteristics of the coloring layer 15 change depending on the concentration of the colorants contained in the coloring layer 15. In particular, when the concentration of all colorants in the coloring layer is low, the reflected light from the light-emitting layer, especially the light due to diffuse reflection, is not significantly attenuated when passing through the coloring layer, and the lightness of the shade increases, so the FI value decreases. On the contrary, when the concentration of all colorants becomes 1% by mass or more, the light due to diffuse reflection is sufficiently absorbed by the pigment particles when passing through the coloring layer 15, so the lightness of the shade decreases and the FI value increases. On the other hand, when the concentration of all colorants becomes excessively high, the effect of the pigment particles absorbing and / or shielding the reflected light from the light-emitting layer 14 becomes large and the lightness of the highlight decreases, so the FI value decreases. Also, since the scattering of light by the pigment particles also causes an increase in the lightness of the shade and thus a decrease in the FI value, the upper limit of the concentration of all colorants is preferably 23% by mass.

[0116] <Transmission characteristics of the coloring layer> [Spectral transmittance] The transmission characteristics of the coloring layer 15 are represented, for example, by its spectral transmittance. The spectral transmittance of the coloring layer 15 is a value obtained by dividing the spectral reflectance measured in a state where the coloring layer 15 is laminated on the light-emitting layer 14 by the spectral reflectance measured in a state where the coloring layer 15 is removed and the surface of the light-emitting layer 14 is exposed. Here, it is expressed as an absolute value. The spectral reflectance measured in a state where the coloring layer 15 is laminated on the light-emitting layer 14 may be the coating film in the state where the coloring layer 15 is laminated on the light-emitting layer 14 in the method shown in FIG. 3.

[0117] When obtaining the spectral transmittance spectrum of the coloring layer 15, the incident angle in the measurement of each spectral reflectance is 45°, and the light-receiving angle is 15° at which the red hue is clearly visible.

[0118] And in the case of the red colorant, since the spectral reflectance rises in the wavelength range of 590 nm to 650 nm, the slope of the tangent of the spectrum at the median value 620 nm of that wavelength range is set within a predetermined range.

[0119] That is, in the colored layer 15 of the present embodiment, the slope of the tangent line at 620 nm in the spectrum of the spectral transmittance is 0.02 nm -1 or more and 0.06 nm -1 or less, preferably 0.03 nm -1 or more and 0.06 nm -1 or less.

[0120] Specifically, FIG. 7 shows the spectrum of the spectral transmittance of the colored layer 15 in the coated plate of F (Example 3) shown in Table 2. For the measurement of the spectral reflectance, the variable-angle spectral color measurement system GCMS-4 manufactured by the above-mentioned Murakami Color Research Institute was used. FIG. 7 is a spectral transmittance spectrum in the measurement wavelength range of 390 to 730 nm. The specifications of the laminated coating film 12 of the coated plate F (Example 3) and the slope of the tangent line at the wavelength of 620 nm of the spectrum are as shown in Table 2.

[0121]

Table 2

[0122] Next, as shown in Table 2, a plurality of coated plates A to E and G having the same configuration as the coated plate F (Example 3) were produced except that the pigment particle size of the colored layer 15 was variously changed, and the spectral transmittance spectra of each coated plate were measured. Then, the slope of the tangent line at 620 nm was obtained from the spectral transmittance spectrum as described above, and the XY and Z values in the XYZ color system were obtained using the equal-color function. XYZ was converted to L * a * b * and the chroma C * =√((a * ) 2 +(b * ) 2 ) was obtained.

[0123] According to the study of the present disclosure, as shown in FIG. 8, the chroma C * is proportional to the slope of the tangent line at the wavelength of 620 nm in the spectral transmittance spectrum. And at a slope of 0.02 nm -1 the chroma C * becomes approximately 50, and at a slope of 0.06 nm -1 the chroma C* becomes approximately 150. Therefore, the slope of the tangent line is 0.02 nm -1 or more, from the viewpoint of obtaining a vivid red color with less turbidity and high transparency, a sufficient chroma C * is considered to be obtained.

[0124] Also, as shown in FIG. 9, the slope of the tangent line depends on the average particle diameter (pigment particle diameter) of the red pigment in the colored layer 15. Here, when the pigment particle diameter exceeds 160 nm, there is a risk that the transparency will decrease due to diffuse reflection by the pigment particles, that is, geometric optical scattering or Mie scattering, resulting in a color development with poor metallic luster. Also, when the pigment particle diameter is less than 2 nm, there is a risk of coloring purple due to Rayleigh scattering. According to FIGS. 8 and 9, when the slope of the tangent line is 0.02 nm -1 or more and 0.06 nm -1 or less, preferably 0.03 nm -1 or more and 0.06 nm -1 or less, the average particle diameter of the pigment particles is 2 nm or more and 160 nm or less, preferably 2 nm or more and 30 nm or less. Thus, both diffuse reflection by the pigment particles and Rayleigh scattering can be avoided, and a vivid red color development with less turbidity and high transparency can be obtained.

[0125] [Optical properties of the laminated coating film] [FI value] The FI value is an index of metallic feeling of X-Rite, Inc., and represents the FF property. As shown in FIG. 10, the FI value is the lightness index L of the reflected light (45° reflected light) with a light incident angle (angle from the perpendicular to the surface) of 45° with respect to the surface of the laminated coating film 12 and a light receiving angle (tilt angle from the specular reflection direction to the light source side) of 45° * 45°, the lightness index L of the reflected light (15° reflected light) with a light receiving angle of 15° * 15°, and the lightness index L of the reflected light (110° reflected light) with a light receiving angle of 110° * 110°, and is a value obtained by the following formula.

[0126] FI = 2.69×(L * 15° - L * 110°) 1.11 / L * 45° 0.86 The FI value is 20 or more, preferably 30 or more, more preferably 35 or more, and particularly preferably 40 or more, from the viewpoint of obtaining excellent vividness of red color development and excellent metallic texture in the laminated coating film 12.

[0127] [Combination of Reflective Characteristics of the Glitter Layer and Transmissive Characteristics of the Coloring Layer] As described above, in the laminated coating film 12 according to the present embodiment, by combining the reflective characteristics of the glitter layer 14 and the transmissive characteristics of the coloring layer 15, excellent color development of the red hue in the laminated coating film 12 and an increase in the FI value are achieved.

[0128] That is, the reflective characteristics of the glitter layer 14 and the transmissive characteristics of the coloring layer 15 work together. In the highlight, red vividly emits with a sense of transparency and brightness, while on the shade side, the brightness decreases, making the red in the highlight more prominent and obtaining a deep and high metallic texture. Thus, a highly designed metallic color that achieves both vividness and depth is realized.

[0129] [Examples] Coated panels having the laminated coating films (the base is an electrodeposition coating film) of Examples 1 to 17 and Comparative Examples 1 to 4 shown in Tables 3 to 5 were produced. Then, the area ratio per unit area of aluminum flakes, Y(5°), Y(15°), the slope of the tangent line of the spectral transmittance spectrum at a wavelength of 620 nm, and the FI value were examined. Also, the vividness of red color development and the strength of contrast were evaluated by an appearance visual test. The appearance visual test was a four - level evaluation of "◎", "○", "△", and "×". The evaluation of the vividness of red and the strength of contrast is such that "◎" is the highest, and it gradually decreases in the order of "○" → "△" → "×".

[0130]

Table 3

[0131]

Table 4

[0132] [Table 5]

[0133] FIG. 11 is a graph showing the dependence of the FI value on Y(5°) and the concentration of the red pigment 25 in the colored layer 15 (pigment concentration) based on the results of Tables 3 and 4. However, k represented by Y(15°)=k×Y(5°) is 0.01 or more and 0.3 or less.

[0134] When the Y(5°) of the bright layer 14 is 30 or more and 700 or less, and the pigment concentration of the colored layer 15 is 1 mass% or more and 17 mass% or less, the FI value can be made 20 or more. Also, when Y(5°) is 150 or more and 500 or less, and the pigment concentration of the colored layer 15 is 4 mass% or more and 10 mass% or less, the FI value can be made 30 or more. When Y(5°) is 200 or more and 400 or less, and the pigment concentration of the colored layer 15 is 5 mass% or more and 9 mass% or less, the FI value can be made 35 or more. When Y(5°) is 200 or more and 300 or less, and the pigment concentration of the colored layer 15 is 5 mass% or more and 7 mass% or less, the FI value can be made 40 or more.

Explanation of Signs

[0135] 11 Vehicle body 11A Steel plate 12 Multilayer coating film 13 Electrodeposition coating film 14 Bright layer 15 Colored layer 16 Transparent clear layer 21 Brightening material 23 First black pigment (black coloring material) 25 Red pigment (red coloring material) 27 Second black pigment (black coloring material)

Claims

1. A laminated coating film comprising a brightening layer containing a brightening material and a black coloring material formed directly or indirectly on the surface of an object to be coated, and a coloring layer containing a red coloring material and having translucency laminated on the brightening layer, wherein the red coloring material is a red pigment, the brightening layer contains aluminum flakes having an average particle diameter of 5 μm or more and 30 μm or less and an average thickness of 10 nm or more and 500 nm or less as the brightening material, the concentration of the aluminum flakes in the brightening layer is 1% by mass or more and 17% by mass or less, the black coloring material contained in the brightening layer is carbon black, the concentration of the carbon black in the brightening layer is 1% by mass or more and 20% by mass or less, the slope of the tangent at 620 nm of the spectral transmittance spectrum of the coloring layer in absolute value obtained by dividing the spectral reflectance measured at a light incident angle of 45° and a light receiving angle of 15° with the coloring layer laminated on the brightening layer by the spectral reflectance measured at a light incident angle of 45° and a light receiving angle of 15° with the surface of the brightening layer exposed by removing the coloring layer is 0.02 nm －１ or more and 0.06 nm －１ or less, characterized in that it is a laminated coating film.

2. In claim 1, the laminated coating film is characterized in that the average particle diameter of the red pigment is 2 nm or more and 160 nm or less.

3. In claim 1 or claim 2, the slope of the tangent is 0.03 nm －１ or more and 0.06 nm －１ or less, characterized in that it is a laminated coating film.

4. In any one of claims 1 to 3, the laminated coating film is characterized in that the surface roughness Ra of the aluminum flakes is 50 nm or less.

5. In any one of claims 1 to 4, The laminated coating film is characterized in that the concentration of the red coloring material in the coloring layer is 1% by mass or more and 17% by mass or less.

6. In any one of Claims 1 to 5, The laminated coating film is characterized in that the coloring layer further contains a black coloring material.

7. In Claim 6, The laminated coating film is characterized in that the concentration of the black coloring material in the coloring layer is 6% by mass or less.

8. In Claim 6 or Claim 7, The laminated coating film is characterized in that the ratio of the black coloring material to the total of the red coloring material and the black coloring material in the coloring layer is 26% by mass or less.

9. In any one of Claims 1 to 8, The laminated coating film is characterized in that the average particle diameter of the carbon black is 200 nm or less.

10. A coated article comprising the laminated coating film according to any one of Claims 1 to 9.

Images