Coating composition, coated article, and method for producing a coated article

Abstract

A coating composition which is a coating composition containing a film-forming resin and a pigment, wherein, based on the spectral reflectance of the reflected light R ‑15 the chroma C * C * in the L * ‑15 C 15 h color system based on the spectral reflectance of the reflected light R * C * and the chroma C * 15 in the L * ‑15 h color system satisfy the following relationship: C * 15 > C * ‑15 > 10 and C * 15 - C ‑15 15 > 20. The reflected light R 45 15 is the reflected light that receives the incident light I 45 incident at an angle of 45 degrees with respect to the surface of the cured coating film of the coating composition at an angle of -15 degrees with respect to the specular reflected light. The reflected light R 45 is the reflected light that receives the incident light I * C * at an angle of 15 degrees with respect to the specular reflected light. And the chroma C * 45 in the L 45 C 45 h color system based on the spectral reflectance of the reflected light R is 10 or less. The reflected light R 45 is the reflected light that receives the incident light I 45 at an angle of 45 degrees with respect to the specular reflected light.

Description

Technical Field

[0001] The present invention relates to a coating composition, a coated article, and a method for manufacturing a coated article. Background Art

[0002] In recent years, due to the diversification of consumer preferences and the pursuit of originality, the designs required for the coating films of automobiles and the like have become diverse. Accordingly, various coating compositions have been developed. For example, Patent Document 1 discloses a coating composition that can obtain a coating film having the following properties: when the observation angle is changed from a face angle to a grazing angle, the hue continuously changes, and the coating film is achromatic at the face angle and chromatic at the grazing angle. Patent Document 2 discloses a coating composition that, conversely, can obtain a coating film that is chromatic at the face angle and achromatic at the grazing angle.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-209167

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2012-046676 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] The present invention has a design different from that of Patent Documents 1 and 2, and an object thereof is to provide a coating composition that can obtain a coating film having a large change in vividness in a high brightness region and being achromatic or a color close thereto when observed in a front region.

[0009] Means for Solving the Problems

[0010] To solve the above problems, the present invention provides the following solutions.

[0011] [1] A coating composition comprising a film-forming resin and a pigment, and the chroma C in the L -15 C * h color system based on the spectral reflectance of the reflected light R * satisfies the following relationship with the chroma C in the L * -15 C 15 h color system based on the spectral reflectance of the reflected light R * C * h color system, where the reflected light R * 15 satisfies the following relationship, and this reflected light R -15The reflected light R is received at an angle of -15 degrees with respect to the specularly reflected light, where the incident light I is incident at an angle of 45 degrees with respect to the surface of the cured coating film of the coating composition. 45 and the reflected light R 15 is received at an angle of 15 degrees with respect to the specularly reflected light for the incident light I. 45

[0012] C * -15 >C * 15 >10, and

[0013] C * -15 -C * 15 >20.

[0014] Moreover, the chroma C in the L*a*b* color system based on the spectral reflectance of the reflected light R 45 is 10 or less, where the reflected light R * C * is received at an angle of 45 degrees with respect to the specularly reflected light for the incident light I. * 45 45 45

[0015] [2] The coating composition according to [1] above, wherein the chroma C * -15 is 50 or more.

[0016] [3] The coating composition according to [1] or [2] above, wherein the chroma C * 15 exceeds 10 and is 40 or less.

[0017] [4] The coating composition according to any one of [1] to [3] above, wherein the lightness L based on the spectral reflectance of the reflected light R -15 and the lightness L based on the spectral reflectance of the reflected light R * -15 satisfy the following relationship: 15 * 15

[0018] L * -15 -L * 15 ≥10.

[0019] [5] The coating composition according to any one of [1] to [4] above, wherein in the wavelength range of 400 nm to 700 nm, the reflected light R -15 has a maximum spectral reflectance SR -15 and the spectral reflectance SR -15 of the reflected light R -15 at the wavelength at which the maximum is reached satisfy the following relationship: 15 of the reflected light R 15 at the wavelength at which the maximum is reached

[0020] SR -15 - SR 15 ≥ 20 (%)

[0021] [6] The coating composition according to any one of [1] to [5] above, wherein in the wavelength range of 400 nm to 700 nm, the spectral reflectance SR -15 of the reflected light R -15 at the wavelength W -15 at which the maximum is reached and the spectral reflectance SR 15 of the reflected light R 15 at the wavelength W 15 at which the maximum is reached satisfy the following relationship:

[0022] │W -15 - W 15 │ ≥ 40 (nm)

[0023] [7] The coating composition according to any one of [1] to [6] above, wherein

[0024] the pigment contains a light-interference flaky pigment,

[0025] and the light-interference flaky pigment has:

[0026] a flaky reflective substrate having a first surface and a second surface opposite to the first surface;

[0027] a first layer containing at least one selected from silica, alumina, and metal fluorides; and

[0028] a second layer containing at least one selected from chromium, aluminum, silver, nickel, palladium, platinum, titanium, vanadium, cobalt, iron, tin, tungsten, molybdenum, rhodium, niobium, copper, and gold,

[0029] and at least two of the first layer and the second layer are alternately arranged on each of the first surface and the second surface with the first layer as the innermost layer.

[0030] [8] A coated article, comprising:

[0031] an object to be coated, and

[0032] The cured coating film of the coating composition according to any one of [1] to [7] provided on the above-mentioned object to be coated.

[0033] [9] A method for manufacturing a coated article, which includes: coating the coating composition according to any one of [1] to [7] on an object to be coated and then curing it.

[0034] Advantages of the Invention

[0035] The coating composition according to the present invention provides a coating composition capable of obtaining a coating film with a large change in vividness in a high brightness region and having a colorless or nearly colorless appearance when observed in the front region. Description of the Drawings

[0036] Figure 1 is a diagram for explaining the angle of reflected light.

[0037] Figure 2 schematically shows the reflected light R -15 and R 15 and an example of a graph showing the change in spectral reflectance of Detailed Description of the Invention

[0038] [Coating Composition]

[0039] The coating composition according to the present disclosure contains a film-forming resin and a pigment.

[0040] The cured coating film of the coating composition according to the present disclosure is colored in a high brightness region and has a large change in vividness. That is, based on the spectral reflectance of the reflected light R -15 in the L * C * h color system, the chroma C * -15 and based on the spectral reflectance of the reflected light R 15 in the L * C * h color system, the chroma C * 15 satisfy the following relationship, where the reflected light R -15 is the reflected light received at an angle of -15 degrees relative to the normal reflected light from the incident light I 45 incident at an angle of 45 degrees relative to the surface of the cured coating film of the coating composition, and the reflected light R 15 is the reflected light received at an angle of 15 degrees relative to the normal reflected light from the light I 45

[0041] C * -15 > C * 15 > 10, and​​​

[0042] C * -15 -C * 15 >20。

[0043] “C * -15 >C * 15 >10” indicates that the reflected lights R -15 and R 15 are both chromatic colors, and the chroma of the reflected light R -15 is higher than that of the reflected light R 15 “C * -15 -C * 15 >20” indicates that the chroma difference between the reflected light R -15 and the reflected light R 15 is greater than 20.

[0044] Moreover, the cured coating film (hereinafter sometimes simply referred to as "cured coating film") of the coating composition involved in the present disclosure is achromatic or a color close thereto when observed in the front region. That is, the chroma C 45 in the L * C * h color system based on the spectral reflectance of the reflected light R * 45 is 10 or less, and the reflected light R 45 is the reflected light that receives the incident light I 45 at an angle of 45 degrees with respect to the specularly reflected light.

[0045] When the cured coating film is observed from its normal direction, it is achromatic. However, if the observation angle is gradually decreased, that is, the angle is changed in a manner that the angle with respect to the specularly reflected light becomes smaller from the normal direction of the coating film (in this case, the direction of 45 degrees with respect to the specularly reflected light), then the chromatic color rapidly increases at a certain angle, which is a hitherto unprecedented design.

[0046] The high-brightness region refers to the range of -25 degrees or more and less than 25 degrees with respect to the specularly reflected light of the light incident at an angle of 45 degrees. The shadow region refers to the range of 75 degrees or more with respect to the specularly reflected light of the light incident at an angle of 45 degrees. The front region is the range between the high brightness and the shadow (more than 25 degrees and less than 75 degrees with respect to the specularly reflected light). In the present disclosure, as the high-brightness region, the region of -15 degrees to 15 degrees with respect to the specularly reflected light, which is also referred to as the ultra-high-brightness region, is observed. In the present disclosure, as the front region, the location of 45 degrees with respect to the specularly reflected light, which is the same as the normal direction of the cured coating film, is observed.

[0047] (Chroma C* -15 , C * 15 , C * 45 )

[0048] Chroma C * -15 is the chroma in the LCh color system based on the spectral reflectance of the reflected light R -15 where the reflected light R * C * h is the reflected light that receives the incident light I incident at an angle of 45 degrees with respect to the surface of the cured coating film at an angle of -15 degrees with respect to the direct reflected light -15 . C 45 * 15 is also the chroma in the LCh color system based on the spectral reflectance of the reflected light R 15 where the reflected light R * C * h is the reflected light that receives the incident light I incident at an angle of 45 degrees with respect to the surface of the cured coating film at an angle of 15 degrees with respect to the direct reflected light 15 45 . C * 45 45 * is also the chroma in the LCh color system based on the spectral reflectance of the reflected light R 45 where the reflected light R * C * h is the reflected light that receives the incident light I incident at an angle of 45 degrees with respect to the surface of the cured coating film at an angle of 45 degrees with respect to the direct reflected light 45 . 45

[0049] Chroma C * -15 is greater than 10. Thus, the cured coating film is ensured to be colored when observed in the high-brightness region. In terms of the aspect that the change in vividness is likely to increase, it is desirable that the chroma C * -15 * is large. The chroma C * -15 can be 50 or more, 55 or more, 60 or more, 65 or more, or 70 or more. The chroma C * -15 is 100 or less, can be 98 or less, can be 95 or less.

[0050] Chroma C * 15 is greater than 10. On the other hand, from the same view as above, it is desirable that the chroma C * 15 is small. The chroma C *15 It can be below 40 or below 35. Chroma C * 15 It can be 15 or above, or 20 or above.

[0051] C * -15 -C * 15 Exceeding 20, it can be 25 or above, or 30 or above, or 35 or above. C * -15 -C * 15 It can be below 70, or below 65, or below 60.

[0052] Chroma C * -15 Is 60 or above, and, Chroma C * 15 Can be exceeding 10 and below 40.

[0053] Chroma C * 45 Is 10 or below. In terms of being closer to achromatic color, it is desired that Chroma C * 45 Is small. Chroma C * 45 It can be below 9, or below 8, or below 5.

[0054] (Luminance L * -15 、L * 15 )

[0055] Luminance L * -15 Is the L based on the spectral reflectance of the reflected light R -15 In the LCh color space. Luminance L * C * In the LCh color space. Luminance L * 15 Is also the L based on the spectral reflectance of the reflected light R 15 In the LCh color space. * C * In the LCh color space.

[0056] Luminance L * -15 And luminance L * 15 Can satisfy the following relationship:

[0057] L * -15 -L * 15≥10

[0058] In this case, the brightness and chroma of the cured coating film can also change simultaneously in the high-brightness region. Thus, the designability is further improved.

[0059] L * -15 -L * 15 It can be 15 or more, or 20 or more. L * -15 -L * 15 It can be 45 or less, or 40 or less.

[0060] In terms of the ease of increasing the change in brightness, it is desirable that the brightness L * -15 is large. The brightness L * -15 It can be 35 or more, or 40 or more. If the brightness L * -15 is 35 or more, the cured coating film ensures a certain degree of brightness in the high-brightness region, and the designability is further improved. The brightness L * -15 It can be 80 or less, or 75 or less.

[0061] From the same viewpoint as above, it is desirable that the brightness L * 15 is small. The brightness L * 15 It can be 50 or less, or 45 or less. The brightness L * 15 It can be 15 or more, or 20 or more.

[0062] (Spectral reflectance SR -15 、SR 15 )

[0063] The spectral reflectance SR -15 is the maximum spectral reflectance (%) of the reflected light R -15 in the wavelength range of 400 nm to 700 nm (visible light region). The spectral reflectance SR 15 is the spectral reflectance of the reflected light R -15 when the spectral reflectance SR -15 reaches the maximum at the wavelength of the reflected light R 15 .

[0064] The spectral reflectance SR -15 and the spectral reflectance SR 15 can satisfy the following relationship:

[0065] SR-15 -SR 15 ≥20 (%)

[0066] In this case, the brightness of the cured coating film can also change together with the chroma in the high-brightness region.

[0067] SR -15 -SR 15 It can be 30% or more, or 35% or more. SR -15 -SR 15 It can be 130% or less, or 120% or less.

[0068] SR -15 For example, it can be 50% or more, or 60% or more, or 65% or more. SR -15 For example, it can be 180% or less, or 170% or less, or 160% or less.

[0069] SR 15 For example, it can be 10% or more, or 20% or more, or 25% or more. SR 15 For example, it can be 80% or less, or 70% or less, or 60% or less.

[0070] (Wavelength W -15 , W 15 )

[0071] Wavelength W -15 is the wavelength W at which the spectral reflectance SR -15 of the reflected light R -15 reaches the maximum within the wavelength range of 400 nm to 700 nm. The wavelength W 15 is also the wavelength W at which the spectral reflectance SR 15 of the reflected light R 15 reaches the maximum.

[0072] Wavelength W -15 and wavelength W 15 can satisfy the following relationship:

[0073] │W -15 value - W 15 value│≥40 (nm)

[0074] This means that the difference between the maximum wavelength of the spectral reflectance of the reflected light R -15 and the maximum wavelength of the spectral reflectance of the reflected light R 15 is relatively large. In this case, the hue of the cured coating film itself can also change in the high-brightness region.

[0075] │W -15 value - W15 The value │ can be 43 nm or more, or can be 45 nm or more. │ W -15 Value - W 15 The value │ can be 80 nm or less, or can be 70 nm or less.

[0076] In L * C * In the L * represents the lightness, C * represents the chroma, and h represents the hue angle. In the L * C * In the L * C * As the value of C * C * increases, the vividness of the measured substance increases, and as the value of C * decreases, the dullness increases. In the L * C

[0077] L * C * The L * a * b color system (CIE1976L * a * b * color space) is calculated. The CIE1976L * a * b * color space can be obtained according to JIS Z 8781-4. The CIEL * a * b color system is determined by the International Commission on Illumination and is described in Section 4.2 of CIE Publication 15.2 (1986). The lightness L * 15 and the lightness L * 110 For example, a multi-angle colorimeter (e.g., trade name: BYK-mac i, manufactured by BYK-Gardner) can be used to obtain it.

[0078] Figure 1 is a diagram illustrating the angle of the reflected light. The specularly reflected light of the incident light I 45 incident at an angle of 45 degrees with respect to the surface of the multilayer coating film is represented by R0. The reflected light received at an angle of -15 degrees with respect to the specularly reflected light of the incident light I 45 is represented by R -15 . The chroma C -15 is calculated from the spectral reflectance of the reflected light R* -15 , Luminance L * -15 . The reflected light received at an angle of 15 degrees with respect to the direct reflected light R0 of the incident light I 45 is represented by R 15 . The chroma C is calculated from the spectral reflectance of the incident light R 15 , luminance L * 15 , luminance L * 15 . The reflected light received at an angle of 45 degrees with respect to the direct reflected light of the incident light I 45 is represented by R 45 . The luminance L is calculated from the spectral reflectance of the reflected light R 45 , luminance L * 45 .

[0079] Figure 2 schematically shows an example of the change in the spectral reflectance of the reflected lights R -15 and R 15 . In the graph, the horizontal axis represents the wavelength and the vertical axis represents the spectral reflectance. In the graph, the peak (maximum value) of the spectral reflectance of the reflected light R 15 is less than the peak (maximum value) of the spectral reflectance of the reflected light R -15 , and in addition, its peak position shifts toward the long wavelength side compared to the peak position of the reflected light R -15 .

[0080] In the graph, the maximum wavelength of the reflected light R -15 exceeds between 600 nm and 700 nm and is red. However, the position of the maximum wavelength of the reflected light R -15 is not limited to this and is set to a desired wavelength range. The magnitude of the spectral reflectance at each wavelength is not limited to this either. In the wavelength range shown in the graph of Figure 2 , there is only 1 peak for each reflected light, or it can be 2 or more.

[0081] (Pigment)

[0082] The coating composition may contain a light-interference flaky pigment as a pigment. Thereby, the change in vividness in the high luminance region increases, and the chroma C * -15 value and the chroma C * 15 value can easily satisfy the above relationship.

[0083] <<Light-interference flaky pigment>>

[0084] The light-interference flaky pigment (hereinafter sometimes simply referred to as "light-interference pigment") includes: a flaky reflective substrate having a first surface and a second surface opposite to the first surface, a first layer, and a second layer. At least two of the above-mentioned first layers and the above-mentioned second layers are alternately arranged on each of the first surface and the second surface with the first layer as the innermost layer. That is, the light-interference pigment has at least four layers on each of the two surfaces of the flaky reflective substrate. Specifically, the light-interference pigment has a structure of second layer / first layer / second layer / first layer / reflective substrate / first layer / second layer / first layer / second layer. Six or more layers can be provided on each of the two surfaces of the reflective substrate.

[0085] The first layer contains at least one selected from silica, alumina, and metal fluorides. Such a first layer is typically transparent and has a low refractive index. Therefore, it does not have a great impact on the light transmittance, and can improve the strength of the light-interference pigment or increase the thickness.

[0086] The second layer contains at least one selected from chromium, aluminum, silver, nickel, palladium, platinum, titanium, vanadium, cobalt, iron, tin, tungsten, molybdenum, rhodium, niobium, copper, and gold. Such a second layer adjusts the light transmittance to generate light interference.

[0087] By alternately arranging two or more low-refractive-index first layers and second layers that generate light interference on each of the two surfaces of the reflective substrate, the coating film thickness of the reflective substrate becomes thicker, and the light reflected by the reflective substrate is easily absorbed by these layers. Therefore, it is considered that the change in vividness in the high-brightness region of the cured coating film increases.

[0088] Flaky means a shape with an aspect ratio (average major axis of the pigment / average thickness of the pigment) exceeding 1.0. The aspect ratio of the flaky pigment is, for example, 20 or more and 300 or less. The aspect ratio of the flaky pigment can be 30 or more. The aspect ratio of the flaky pigment can be 200 or less.

[0089] The average thickness of the light-interference pigment is obtained by observing the cross-section of the cured coating film containing the light-interference pigment using a transmission electron microscope (TEM) and averaging the thicknesses of 100 randomly selected light-interference pigments.

[0090] The average thickness of the light-interference pigment is, for example, 0.01 μm or more and 1.2 μm or less. The average thickness of the light-interference pigment can be 0.04 μm or more. The average thickness of the light-interference pigment can be 1.1 μm or less.

[0091] The average major axis of the optically interfering pigment is synonymous with the average particle size D50. The average particle size D50 of the optically interfering pigment can be, for example, 10 μm or more and 100 μm or less. The lower limit of the average particle size D50 of the optically interfering pigment can be 15 μm, 20 μm, 25 μm, or 30 μm. The upper limit of the average particle size D50 of the optically interfering pigment can be 90 μm, 80 μm, 70 μm, or 60 μm.

[0092] The average particle size D50 of the optically interfering pigment can be determined by measuring the maximum lengths of arbitrarily selected 30 optically interfering pigments using a shape analysis laser microscope (for example, VK-X250 manufactured by Keyence Corporation) and obtaining them in the form of their average value.

[0093] The reflective substrate has a spectral reflectance of 5% or more and 100% or less in the wavelength range of 400 nm to 700 nm. The reflective substrate can be formed of a metal, a metal compound, an alloy, a non-metal, or a combination thereof. Among them, the reflective substrate can be a metal, a metal compound, an alloy, or a combination thereof. Examples of the metal and the alloy include: aluminum, copper, silver, gold, platinum, titanium, palladium, nickel, cobalt, niobium, chromium, tin, and their alloys, and combinations thereof. Examples of the metal compound include: carbides, oxides, nitrides, sulfides of the above metals, and combinations thereof. Among them, the reflective substrate can be aluminum.

[0094] The thickness of the reflective substrate can be, for example, 5 nm or more and 1200 nm or less. The lower limit of the thickness of the reflective substrate can be 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 40 nm, 50 nm, 60 nm, or 70 nm. The upper limit of the thickness of the reflective substrate can be 1200 nm, 1100 nm, 1000 nm, 900 nm, 800 nm, 700 nm, 600 nm, or 500 nm.

[0095] The first layer has, for example, a refractive index of less than 1.65. The first layer particularly may contain magnesium fluoride. The thickness of the first layer is appropriately set according to the desired refractive index. The thickness of the first layer can be, for example, 100 nm or more and 1000 nm or less. The thickness of the first layer can be 500 nm or less, can also be 300 nm or less, and can further be 250 nm or less.

[0096] The second layer can be translucent or opaque. The second layer may contain chromium or nickel, especially chromium. The above metals can be included in the second layer as alloys, metal compounds, or mixtures with other substances. As other substances, for example, carbon, graphite, silicon, germanium, Celmet (porous metal body), iron oxide, or other metal oxides, and dielectric matrix can be cited. As alloys, for example, Inconel (Ni-Cr-Fe), stainless steel, Hastelloy (Ni-Mo-Fe; Ni-Mo-Fe-Cr; Ni-Si-Cu), various titanium alloys, and cobalt-nickel alloys can be cited. As mixtures, for example, Ti / C, Ti / W, Ti / Nb, and Ti / Si can be cited. As metal compounds, for example, titanium silicide (TiSi2) and titanium boride (TiB2) can be cited.

[0097] The thickness of the second layer is appropriately set according to the desired optical interference properties. The thickness of the second layer can be, for example, 1 nm or more and 50 nm or less. The thickness of the second layer can be 5 nm or more. The thickness of the second layer can be 10 nm or less.

[0098] In one embodiment, the optical interference pigment has a structure of Cr (second layer) / MgF2 (first layer) / Cr (second layer) / MgF2 (first layer) / Al (substrate) / MgF2 (first layer) / Cr (second layer) / MgF2 (first layer) / Cr (second layer).

[0099] The components contained in the multiple first layers can be the same or different from each other. The thicknesses of the multiple first layers can be the same or different from each other. The components contained in the multiple second layers can be the same or different from each other. The thicknesses of the multiple second layers can be the same or different from each other.

[0100] The optical interference pigment can be colored. As the coloring material, as long as it does not interfere with the effects of the optical interference pigment, there is no particular limitation, and it can be appropriately selected.

[0101] As the optical interference pigment, commercially available products can be used. As the optical interference pigment, for example, the ChromaFlair (trademark) series of VIAVISolutions can be used.

[0102] The content of the optical interference pigment, that is, the mass ratio (PWC) of the optical interference pigment contained in the coating composition to the solid components of the resin is, for example, 1% by mass or more and 50% by mass or less. The PWC of the optical interference pigment can be 5% by mass or more, or 8% by mass or more. The PWC of the optical interference pigment can be 40% by mass or less, or 35% by mass or less. The solid components of the resin refer to the solid components of the total resin components such as the film-forming resin and curing agent described later.

[0103] <<Other pigments>>

[0104] The coating composition may contain pigments other than the light-interference pigments. As other pigments, for example, the following can be cited: coloring pigments, extender pigments, rust-inhibiting pigments, light-interference pigments other than the above-mentioned light-interference pigments, and brightening pigments. There is no particular limitation on the mass ratio (PWC) of other pigments, as long as it is within the range that does not impair the effects of the coating composition according to the present disclosure. The mass ratio (PWC) of other pigments can be 15% by mass or less, can also be 13% by mass or less, and can further be 10% by mass or less.

[0105] The coloring pigment can be inorganic or organic. The coloring pigment can be colored or achromatic. As organic coloring pigments, for example, the following can be cited: azo chelate pigments, insoluble azo pigments, condensed azo pigments, diketopyrrolopyrrole pigments, phthalocyanine pigments, indigo pigments, perinone pigments, perylene pigments, bis alkane pigments, quinacridone pigments, isoindolinone pigments, and metal complex pigments. As inorganic coloring pigments, for example, the following can be cited: chrome yellow, iron oxide yellow, iron oxide red, carbon black, and titanium dioxide. These can be used alone or in combination of two or more.

[0106] As extender pigments, for example, the following can be cited: calcium carbonate, barium sulfate, clay, and talc. These can be used alone or in combination of two or more.

[0107] As other light-interference pigments and brightening pigments, the following can be cited: mica pigments such as interference mica, muscovite, and colored mica; graphite pigments; glass flake pigments; metal pigments such as aluminum, copper, zinc, iron, nickel, tin, aluminum oxide, chromium oxide, and alloys containing them. These can be used alone or in combination of two or more. Other light-interference pigments and brightening pigments can be colored.

[0108] (Film-forming resin)

[0109] As film-forming resins, for example, the following can be cited: acrylic resins, acrylic silicone resins, polyester resins, polyurethane resins, epoxy resins, fluororesins, and silicone resins. These can be used alone or in combination of two or more. Among them, it can be an acrylic resin.

[0110] In the aqueous coating composition, these resins can be contained as emulsions, can also be contained as dispersions, or can further be contained in a state dissolved in a solvent.

[0111] For example, an acrylic resin emulsion can be prepared by emulsion polymerization of α,β-ethylenically unsaturated monomers. Examples of the α,β-ethylenically unsaturated monomers include (meth)acrylates, α,β-ethylenically unsaturated monomers having an acid group, and α,β-ethylenically unsaturated monomers having a hydroxyl group. The monomers are used singly or in combination of two or more.

[0112] Examples of the (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, phenyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, dicyclopentadienyl (meth)acrylate, and dihydrodicyclopentadienyl (meth)acrylate. The (meth)acrylate represents acrylate and methacrylate.

[0113] Examples of the α,β-ethylenically unsaturated monomer 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-hydrogen-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'-vinyldibenzophenone.

[0114] Examples of the α,β-ethylenically unsaturated monomer having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, allyl alcohol, methallyl alcohol, and their adducts with ε-caprolactone.

[0115] Other α,β-ethylenically unsaturated monomers can 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.

[0116] The method of emulsion polymerization is not particularly limited. For example, an emulsifier can be dissolved in water, or in an aqueous medium containing organic solvents such as alcohols, ethers (e.g., dipropylene glycol monomethyl ether, propylene glycol monomethyl ether, etc.) as needed, and an α,β-ethylenically unsaturated monomer and a polymerization initiator are added dropwise under heating and stirring. The α,β-ethylenically unsaturated monomer can be pre-emulsified by an emulsifier.

[0117] As the polymerization initiator and the emulsifier, substances commonly used by those skilled in the art can be used. As needed, chain transfer agents such as mercaptans (e.g., lauryl mercaptan) and α-methylstyrene dimer can be used to adjust the molecular weight. The reaction temperature, reaction time, etc. can be appropriately selected within the range commonly adopted by those skilled in the art. The obtained acrylic resin emulsion is neutralized with an alkali as needed.

[0118] The number-average molecular weight of the acrylic resin (acrylic resin emulsion) obtained by emulsion polymerization can be 3,000 or more. The hydroxyl value (solid content hydroxyl value) of the acrylic resin can be 20 mgKOH / g or more and 180 mgKOH / g or less. The acid value (solid content acid value) of the acrylic resin can be 1 mgKOH / g or more and 80 mgKOH / g or less.

[0119] The number-average molecular weight is determined by the GPC method using polystyrene as the standard. The acid value and the hydroxyl value are calculated from the monomer composition used for preparation according to the provisions of JIS.

[0120] The acrylic resin dispersion can be prepared, for example, by solution polymerization of the above-mentioned α,β-ethylenically unsaturated monomer and dispersion using a basic compound.

[0121] The water-soluble acrylic resin can be prepared, for example, by solution polymerization of the above-mentioned α,β-ethylenically unsaturated monomer and solubilization using a basic compound.

[0122] The acrylic resin blended in the solvent-based coating composition can be prepared, for example, by solution polymerization of the α,β-ethylenically unsaturated monomer. The number-average molecular weight of the above-mentioned acrylic resin is, for example, 1,000 or more and 20,000 or less. The acid value (solid content acid value) of the above-mentioned acrylic resin can be 1 mgKOH / g or more and 80 mgKOH / g or less. The hydroxyl value (solid content hydroxyl value) of the above-mentioned acrylic resin can be 101 mgKOH / g or more and 200 mgKOH / g or less.

[0123] (Curing agent)

[0124] The coating composition can contain a curing agent. The curing agent reacts with the film-forming resin and forms a cured coating film together with it.

[0125] As curing agents, for example, the following can be cited: melamine resins, blocked isocyanate compounds, epoxy compounds, aziridine compounds, carbodiimide compounds, oxazoline compounds, metal ions. These are used alone or in combination of two or more. Among them, at least one of a melamine resin and a blocked isocyanate compound can be used.

[0126] The melamine resin can be water-soluble or water-insoluble. The melamine resin has a structure in which hydrogen atoms or substituents (alkylether groups, hydroxymethyl groups, etc.) are bonded via three nitrogen atoms around a melamine nucleus (triazine nucleus). The melamine resin is usually composed of a polynuclear body in which multiple melamine nuclei are bonded to each other. The melamine resin can be a mononuclear body composed of one melamine nucleus.

[0127] Commercially available melamine resins can be used. As commercially available melamine resins, for example, the Cymel series (trade name) manufactured by Allnex Co., Ltd., 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; the U-VAN (trade name) series manufactured by Mitsui Chemicals, Inc. These are used alone or in combination of two or more.

[0128] The blocked isocyanate compound can be prepared by adding a blocking agent having an active hydrogen to a polyisocyanate composed of trimethylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, etc.

[0129] The content of the curing agent can be 10% by mass or more and 80% by mass or less of the resin solid content contained in the coating composition. The above content of the curing agent can be 15% by mass or more. The above content of the curing agent can be 60% by mass or less.

[0130] (Organic compound containing a phosphoric acid group)

[0131] The coating composition may further contain an organic compound containing a phosphoric acid group. By the compound containing a phosphoric acid group, it is easy to improve the dispersibility of the light interference pigment.

[0132] The content of the phosphoric acid group-containing compound may be 0.1% by mass or more and 15% by mass or less of the total solid content of the coating composition. The above content of the phosphoric acid group-containing compound may be 1% by mass or more. The above content of the phosphoric acid group-containing compound may be 12% by mass or less.

[0133] The phosphoric acid group-containing compound only needs to have a phosphoric acid group (-P(=O)(OR)2, where R is independently hydrogen or a hydrocarbon group) and is not particularly limited. The phosphoric acid group-containing compound is, for example, at least one of an alkyl phosphate having an alkyl group with 4 to 30 carbon atoms and a phosphoric acid group-containing polymer having a phosphoric acid group value of 5 mg KOH / g or more and 300 mg KOH / g or less.

[0134] <Alkyl phosphate>

[0135] The alkyl phosphate has an alkyl group with 4 to 30 carbon atoms. Examples of the alkyl phosphate include: monoalkyl phosphate, dialkyl phosphate, and mixtures thereof. In the dialkyl phosphate, the two alkyl groups may be the same or different. The dialkyl phosphate preferably has two identical alkyl groups.

[0136] Examples of the alkyl group with 4 to 30 carbon atoms include: butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, docosyl, tetracosyl, hexacosyl, and octacosyl. The alkyl group may be linear or branched.

[0137] Examples of the alkyl phosphate include: butyl acid phosphate (a mixture of monobutyl phosphate and dibutyl phosphate), 2-ethylhexyl acid phosphate (a mixture of mono-2-ethylhexyl phosphate and di-2-ethylhexyl phosphate), isodecyl acid phosphate (a mixture of monoisodecyl phosphate and diisodecyl phosphate), dilauryl acid phosphate, lauryl acid phosphate (a mixture of monolauryl phosphate and dilauryl phosphate), tridecyl acid phosphate (a mixture of monotridecyl phosphate and bis(tridecyl) phosphate), monostearyl acid phosphate, distearyl acid phosphate, stearyl acid phosphate (a mixture of monostearyl phosphate and distearyl phosphate), isostearyl acid phosphate (a mixture of monoisostearyl phosphate and diisostearyl phosphate), oleyl acid phosphate (a mixture of monooleyl phosphate and dioleyl phosphate), docosyl acid phosphate (a mixture of monodocosyl phosphate and didocosyl phosphate).

[0138] <Phosphoric acid group-containing polymer>

[0139] The phosphoric acid group-containing polymer has a phosphoric acid group value of 5 mgKOH / g or more and 300 mgKOH / g or less. The phosphoric acid group value of the phosphoric acid group-containing polymer can be 10 mgKOH / g or more, or can be 50 mgKOH / g or more. The phosphoric acid group value of the phosphoric acid group-containing polymer can be 250 mgKOH / g or less, or can be 150 mgKOH / g or less.

[0140] The phosphoric acid group value is calculated according to the acid value measurement method of JIS K56012-1. Specifically, the acid value is the number of mg of potassium hydroxide (KOH) required to neutralize the free acid in 1 g of the non-volatile matter of the product.

[0141] The number average molecular weight of the phosphoric acid group-containing polymer is, for example, 1,000 or more and 50,000 or less. The number average molecular weight of the phosphoric acid group-containing polymer can be 3,000 or more, or can be 5,000 or more. The number average molecular weight of the phosphoric acid group-containing polymer can be 30,000 or less, or can be 20,000 or less.

[0142] Examples of the phosphoric acid group-containing polymer include: acrylic resins, polyester resins, polyether resins, and epoxy resins having a phosphoric acid group value of 5 mgKOH / g or more and 300 mgKOH / g or less. These are used alone or in combination of two or more. Among them, it can be a phosphoric acid group-containing acrylic resin. The phosphoric acid group-containing acrylic resin is obtained, for example, by polymerizing a phosphoric acid group-containing α,β-ethylenically unsaturated monomer or copolymerizing the monomer with other α,β-ethylenically unsaturated monomers without a phosphoric acid group. In particular, by using the above-mentioned light-interfering pigment and the phosphoric acid group-containing acrylic resin together, the color vividness in the high-brightness region is more likely to change.

[0143] (Additive)

[0144] The coating composition may contain additives commonly used by those skilled in the art. Examples of the additives include: surface modifiers, viscosity control agents, thickeners, antioxidants, ultraviolet light inhibitors, and defoamers.

[0145] [Coated article]

[0146] The coated article according to the present disclosure includes a substrate and the above-mentioned cured coating film provided on the substrate. The coated article having the above-mentioned cured coating film has a large change in vividness in the high-brightness region and is observed as achromatic or a color close thereto in the front region. Therefore, when the coated article is observed from the normal direction of the cured coating film, it is achromatic, but when the observation angle is gradually decreased, the color rapidly increases at an angle exceeding a certain angle, which is a design that has not existed so far.

[0147] ·First Embodiment

[0148] In the first embodiment, the coated article includes: a substrate, the cured coating film (hereinafter sometimes referred to as the "base coating film") provided on the substrate, and a transparent coating film provided on the base coating film.

[0149] (Substrate)

[0150] Examples of the material of the substrate include: metal, plastic, and foam. Among them, it can be metal (especially castings), or metal that can be electrodeposited. Examples of such metals include: iron, copper, aluminum, tin, zinc, etc. and alloys containing these metals.

[0151] The shape of the substrate is not particularly limited, and it can be flat or three-dimensionally formed. Specifically, examples of the substrate include: car bodies such as sedans, trucks, motorcycles, buses, and their components.

[0152] The metal substrate can be subjected to chemical conversion treatment using a phosphoric acid-based chemical conversion treatment agent, a zirconium-based chemical conversion treatment agent, etc. and electrodeposition coating. The electrodeposition coating composition can be cationic or anionic. The cationic electrodeposition coating composition can form a coating film with excellent corrosion resistance.

[0153] The metal substrate can have an electrodeposition coating film and an intermediate coating film provided thereon. The intermediate coating film is usually provided for the purpose of improving the adhesion and durability of the multi-layer coating film. The coating composition for the intermediate coating can, for example, contain 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 substances as those contained in the coating composition according to the present disclosure.

[0154] (Base coating film)

[0155] The base coating film is formed from the coating composition according to the present disclosure (hereinafter sometimes referred to as the "base coating composition"). The thickness of the base coating film can be 0.2 μm or more and 50 μm or less. The thickness of the base coating film can be 3 μm or more. The thickness of the base coating film can be 40 μm or less, or 30 μm or less, or 20 μm or less.

[0156] (Transparent coating film)

[0157] The transparent coating film protects the base coating film. The thickness of the transparent coating film can be, for example, 10 μm or more and 80 μm or less. The thickness of the transparent coating film can be 20 μm or more. The thickness of the transparent coating film can be 60 μm or less.

[0158] The transparent coating film is formed from a transparent coating composition. The transparent coating composition can be solvent-based, water-based, or powder-based. Considering aspects such as transparency or acid etching resistance, the solvent-based transparent coating composition may contain an acrylic resin and / or a polyester resin as the film-forming resin, and an amino resin and / or an isocyanate as the curing agent. Additionally, the solvent-based transparent coating composition may contain an acrylic resin and / or a polyester resin having a carboxylic acid and / or an epoxy group.

[0159] The transparent coating composition may contain the various pigments described above within a range that does not impair the transparency and the effects of the coating composition of the present disclosure. The transparent coating composition may contain various additives as needed. Examples of the additives include: ultraviolet absorbers, antioxidants, defoamers, surface modifiers, and anti-pinhole agents.

[0160] ·Second Embodiment

[0161] In the second embodiment, the coated article includes: a substrate, another cured coating film provided on the substrate (hereinafter referred to as the "first base coating film"), a cured coating film formed from the coating composition of the present disclosure provided on the first base coating film (hereinafter referred to as the "second base coating film"), and a transparent coating film provided on the second base coating film. The substrate and the transparent coating film are the same as those in the first embodiment. The second base coating film is formed from the coating composition of the present disclosure and is the same as the base coating film in the first embodiment. Hereinafter, the first base coating film will be described.

[0162] (First Base Coating Film)

[0163] The first base coating film is formed from a first base coating composition. The first base coating composition may contain a first film-forming resin and pigments other than the above-described light-interference pigments.

[0164] Examples of the first film-forming resin include: the same resins as those used in the coating composition of the present disclosure. The two may be of the same type or different types. As the pigments, as long as they are other than the above-described light-interference pigments, they can be used without particular limitation. In addition, the first base coating composition may contain the same components as the coating composition of the present disclosure.

[0165] The thickness of the first base coating film can be, for example, 0.2 μm or more and 20 μm or less. The thickness of the first base coating film can be 5 μm or more. The thickness of the first base coating film can be 15 μm or less, or 10 μm or less.

[0166] [Manufacturing Method of Coated Article]

[0167] The manufacturing method of the coated article involved in the present disclosure includes: coating the coating composition involved in the present disclosure on the object to be coated and then curing it. Thus, the above-mentioned coated article is obtained.

[0168] The coated article according to the first embodiment further having a transparent coating film is obtained by sequentially coating the coating composition (base coating composition) involved in the present disclosure and the transparent coating composition on the object to be coated and then curing both simultaneously.

[0169] The coated article according to the second embodiment further having a first base coating film and a transparent coating film is obtained by sequentially coating the above-mentioned first base coating composition and the coating composition (second base coating composition) involved in the present disclosure on the object to be coated, curing both simultaneously, then coating the transparent coating composition and curing it.

[0170] In addition, the coated article according to the second embodiment can be obtained by sequentially coating the above-mentioned first base coating composition, the coating composition (hereinafter sometimes referred to as "second base coating composition") involved in the present disclosure, and the transparent coating composition and then curing them simultaneously.

[0171] Preheating can be performed after coating the first base coating composition and before coating the coating composition (second base coating composition) involved in the present disclosure. Preheating can be performed after coating the coating composition involved in the present disclosure and before coating the transparent coating composition.

[0172] As the coating method, for example, air spray coating, airless spray coating, electrostatic spray coating, multi-stage coating (preferably two-stage coating) by air electrostatic spray coating, and coating by combining air electrostatic spray coating with a rotary atomizing electrostatic coater can be mentioned.

[0173] Curing of each coating 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).

[0174] Examples

[0175] The present invention will be described more specifically by the following examples, but the present invention is not limited to these. In the examples, unless otherwise specified, "parts" and "%" are based on mass standards.

[0176] [Production Example 1] Production of an acrylic resin emulsion (film-forming resin)

[0177] 633 parts of deionized water was added to the reaction vessel, and the temperature was raised to 80 °C while mixing and stirring in a nitrogen stream. Next, a first-stage monomer mixture of 75.65 parts by mass of styrene (ST), 178.96 parts by mass of methyl methacrylate (MMA), 75.94 parts by mass of n-butyl acrylate (BA), 64.45 parts by mass of 2-ethylhexyl acrylate (2-EHA), 105.00 parts by mass of 2-hydroxyethyl methacrylate (HEMA), a monomer emulsion composed of 25.00 parts of Aqualon HS-10 (polyoxyethylene alkyl allyl phenyl ether sulfate, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), 25.00 parts of Adeka Reasoap NE-20 (α-[1-[(allyloxy)methyl]-2-(nonylphenoxy)ethyl]-ω-hydroxyoxyethylene, manufactured by Asahi Denka Co., Ltd.) and 400 parts of deionized water, and an initiator solution composed of 1.2 parts of ammonium persulfate and 500 parts of deionized water were added dropwise to the reaction vessel in parallel. After completion of the dropwise addition, aging was carried out at the same temperature for 1 hour.

[0178] Moreover, a second-stage monomer mixture of 53.65 parts by mass of styrene (ST), 178.96 parts by mass of methyl methacrylate (MMA), 75.94 parts by mass of n-butyl acrylate (BA), 64.45 parts by mass of 2-ethylhexyl acrylate (2-EHA), 105.00 parts by mass of 2-hydroxyethyl methacrylate (HEMA), 22 parts by mass of acrylic acid, a monomer emulsion composed of 10 parts of Aqualon HS-10 and 250 parts of deionized water, and an initiator solution composed of 3.0 parts of ammonium persulfate and 500 parts of deionized water were added dropwise to the reaction vessel in parallel at 80 °C over 1.5 hours. After completion of the dropwise addition, aging was carried out at the same temperature for 2 hours.

[0179] Next, it was cooled to 40 °C, filtered through a 400-mesh filter, 100 parts of deionized water and 1.6 parts of dimethylaminoethanol were added, and the pH was adjusted to 6.5 to obtain an acrylic resin emulsion having an average particle diameter of 150 nm, a non-volatile content of 35%, a solid component acid value of 20 mgKOH / g, and a hydroxyl value of 100 mgKOH / g.

[0180] [Production Example 2] Production of an organic compound containing a phosphoric acid group

[0181] Forty parts of ethoxypropanol were charged into a 1-liter reaction vessel equipped with a stirrer, a temperature regulator, and a condenser tube. At 120 °C, 40 parts of a solution prepared by dissolving 20 parts of Phosmer PP (manufactured by Unichemical Co., acid phosphoric acid oxidized hexa(propylene oxide) monomethacrylate) in 4 parts of styrene, 35.96 parts of n-butyl acrylate, 18.45 parts of 2-ethylhexyl methacrylate, 13.92 parts of 2-hydroxyethyl methacrylate, 7.67 parts of methacrylic acid, and 20 parts of ethoxypropanol, and 121.7 parts of a monomer solution composed of 1.7 parts of azobisisobutyronitrile were added dropwise thereto over 3 hours, and then stirring was continued for 1 hour. The acid value of the obtained phosphoric acid group-containing organic compound was 105 mgKOH / g, wherein the phosphoric acid group value was 55 mgKOH / g, the hydroxyl value was 60 mgKOH / g, the number average molecular weight was 6,000, and the non-volatile content was 63%.

[0182] It should be noted that in the examples of the present specification, the number average molecular weight was measured using "HLC8220GPC" (trade name, manufactured by Tosoh Corporation) as a GPC device, 4 "Shodex KF-606M" and "Shodex KF-603" (both manufactured by Showa Denko K.K., trade name) as columns, under the conditions that the mobile phase was tetrahydrofuran, the measurement temperature was 40 °C, the flow rate was 0.6 cc / minute, and the detector was RI.

[0183] In addition, in the examples of the present specification, the acid value and the phosphoric acid group value of the phosphoric acid group-containing organic compound were calculated according to the definition of the acid value in JIS K5601 2-1 (the number of mg of potassium hydroxide (KOH) required to neutralize the free acid in 1 g of the sample (non-volatile matter)). In addition, the hydroxyl value was calculated according to the definition of the hydroxyl value in JIS K0070 (the number of mg of potassium hydroxide required to neutralize the acetic acid combined with the hydroxyl group when 1 g of the sample was acetylated).

[0184] [Production Example 3] Production of water-soluble acrylic resin

[0185] 23.89 parts of tripropylene glycol monomethyl ether and 16.11 parts of propylene glycol monomethyl ether were added to a reaction vessel, and the temperature was raised to 105 °C while mixing and stirring in a nitrogen stream. Subsequently, 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 an initiator solution composed of 100 parts of this monomer mixture, 10.0 parts of tripropylene glycol monomethyl ether, and 1 part of tert-butyl peroxy-2-ethylhexanoate was added dropwise to the reaction vessel in parallel over 3 hours. After the dropwise addition was completed, aging was carried out at the same temperature for 0.5 hour.

[0186] Moreover, an initiator solution composed of 5.0 parts of tripropylene glycol methyl ether and 0.3 part of tert-butyl peroxy-2-ethylhexanoate was added dropwise to the reaction vessel over 0.5 hour. After the addition was completed, aging was carried out at the same temperature for 2 hours.

[0187] After distilling off 16.1 parts of the solvent under reduced pressure (70 torr) at 110 °C using a solvent removal device, 204 parts of deionized water and 7.1 parts of dimethylaminoethanol were added to obtain a water-soluble acrylic resin solution. The non-volatile content of the obtained water-soluble acrylic resin solution was 30%, the solid component 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).

[0188] Details of pigments and the like used in the examples and comparative examples are shown in Table 1.

[0189] [Table 1]

[0190]

[0191] [Example 1]

[0192] (1) Preparation of the base coating composition

[0193] (1-1) Preparation of the colored pigment dispersion 1

[0194] Using a stirrer such as a disperser, 34.5 parts of the water-soluble acrylic resin solution obtained in Production Example 3, 10.4 parts of carbon black (colored pigment), 18.6 parts of a pigment dispersant, 36.0 parts of ion-exchanged water, and 0.5 part of an antifoaming agent were mixed. Then, dispersion was carried out using a disperser filled with 0.05 mm zirconia beads as a medium at a volume filling rate of 70% to obtain the colored pigment dispersion 1.

[0195] (1-2) Preparation of the base coating composition

[0196] 133.3 parts of the acrylic resin emulsion of Production Example 1, 9.0 parts of dimethylaminoethanol, 35.6 parts of Cymel 370N (curing agent, solid content 87%), 13.5 parts of the colored pigment dispersion 1, 10 parts by mass of an optical interference pigment based on 100 parts by mass of the resin solid content, 5 parts of the phosphoric acid group-containing organic compound of Production Example 2, 0.4 part of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of NOIGEN EA-207D (surfactant, solid content 55%), and 3 parts of linoleic acid were uniformly dispersed. After adding dimethylaminoethanol and adjusting the pH to 8.1, it was diluted with deionized water to obtain an aqueous base coating composition having a resin solid content concentration of 24.5 mass%.

[0197] (2) Formation of the multilayer coating film

[0198] Electrodeposition coating was applied to a matte steel plate with a thickness of 0.8 mm, a length of 30 cm, and a width of 40 cm that had been treated with zinc phosphate. The coating used was "Power Top U-50" (manufactured by Nippon Paint Automotive Coatings Co., Ltd.), a cationic electrodeposition coating composition, to achieve a dry film thickness of 20 μm, followed by baking at 160 °C for 30 minutes. Using an Anest Iwata air spray gun model W-101-132G, the obtained coated plate was air spray coated with an intermediate coating composition "OP-30P Middle grey" (manufactured by Nippon Paint Automotive Coatings Co., Ltd., a polyester / melamine-based coating, pre-diluted for 25 seconds (measured at 20 °C using a No. 4 Ford cup)) to achieve a dry film thickness of 35 μm, and then baked at 140 °C for 30 minutes to cure it. By performing these operations, a coated object with an electrodeposition coating film and an intermediate coating film was obtained.

[0199] Under the conditions of a room temperature of 23 °C and a humidity of 68%, the above-mentioned aqueous base coating composition was air spray coated onto the coated object to achieve a dry film thickness of 15 μm. After leaving it for 4 minutes, preheating was carried out at 80 °C for 5 minutes.

[0200] After the loaded plate was cooled to room temperature, it was air spray coated with a clear coating composition (MAC flow-O-1810, a solvent-based clear coating manufactured by Nippon Paint Automotive Coatings Co., Ltd.) to achieve a dry film thickness of 35 μm, and left for 7 minutes. Then, the coated plate was baked at 140 °C for 30 minutes using a dryer, and a coated article with a multilayer coating film composed of a base coating film and a clear coating film was obtained.

[0201] [Example 2]

[0202] An aqueous base coating composition and a coated article were obtained in the same manner as in Example 1, except that the coloring pigment dispersion 1 was not blended.

[0203] [Comparative Example 1]

[0204] (1) Preparation of the base coating composition

[0205] (1-1) Preparation of the coloring pigment dispersion 2

[0206] Using a stirrer such as a disperser, 76.8 parts of the water-soluble acrylic resin solution obtained in Production Example 3, 11.7 parts of perylene red (coloring pigment), 12.5 parts of anchor red (coloring pigment), 3.0 parts of carbon black (coloring pigment), 16.0 parts of titanium oxide (coloring pigment), 22.7 parts of a pigment dispersant, 59.0 parts of ion-exchanged water, and 0.6 part of an antifoaming agent were mixed. Subsequently, dispersion was carried out using a disperser filled with 0.05 mm zirconia beads at a volume filling rate of 70% as the medium to obtain a colored pigment dispersion 2.

[0207] (1-2) Preparation of the base coating composition

[0208] 143.3 parts of the acrylic resin emulsion of Production Example 1, 1.4 parts of dimethylaminoethanol, 35.6 parts of Cymel 370N (curing agent, solid content: 87%), 89.4 parts of the colored pigment dispersion 2, 1.4 parts of other light-interfering pigment 1 relative to 100 parts by mass of resin solid content, 5 parts of the phosphoric acid group-containing organic compound of Production Example 2, 0.4 part of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of NOIGEN EA-207D (surfactant, solid content: 55%), and 3 parts of linoleic acid were uniformly dispersed. After adding dimethylaminoethanol and adjusting the pH to 8.1, it was diluted with deionized water to prepare an aqueous base coating composition having a resin solid content concentration of 24.5% by mass.

[0209] (2) Formation of the multilayer coating film

[0210] Using the aqueous base coating composition obtained by the above preparation, a coated article having a multilayer coating film was obtained in the same manner as in Example 1.

[0211] [Comparative Example 2]

[0212] (1) Preparation of the base coating composition

[0213] (1-1) Preparation of the colored pigment dispersion 3

[0214] Using a stirrer such as a disperser, 59.8 parts of the water-soluble acrylic resin solution obtained in Production Example 3, 11.7 parts of perylene red (coloring pigment), 6.3 parts of carbon black (coloring pigment), 25.3 parts of a pigment dispersant, 56.8 parts of ion-exchanged water, and 0.8 part of an antifoaming agent were mixed. Subsequently, dispersion was carried out using a disperser filled with 0.05 mm zirconia beads at a volume filling rate of 70% as the medium to obtain a colored pigment dispersion 3.

[0215] (1-2) Preparation of the base coating composition

[0216] 143.3 parts of the acrylic resin emulsion of Production Example 1, 1.4 parts of dimethylaminoethanol, 35.6 parts of Cymel 370N (curing agent, solid content 87%), 56.1 parts of coloring pigment dispersion 3, 6.2 parts of other optical interference pigments relative to 100 parts by mass of resin solid content 2, 5 parts of the phosphoric acid group-containing organic compound of Production Example 2, 0.4 part of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of NOIGEN EA-207D (surfactant, solid content 55%), 3 parts of linoleic acid were added. After adding dimethylaminoethanol and adjusting the pH to 8.1, it was diluted with deionized water to prepare an aqueous base coating composition having a resin solid content concentration of 24.5% by mass.

[0217] (2) Formation of a multilayer coating film

[0218] Using the aqueous base coating composition obtained by the above preparation, a coated article having a multilayer coating film was obtained in the same manner as in Example 1.

[0219] [Comparative Example 3]

[0220] (1) Preparation of a base coating composition

[0221] (1-1) Preparation of coloring pigment dispersion 4

[0222] 74.1 parts of the water-soluble acrylic resin solution obtained in Production Example 3, 3.1 parts of perylene red (coloring pigment), 13.1 parts of anchor red (coloring pigment), 10.4 parts of carbon black (coloring pigment), 2.8 parts of titanium oxide (coloring pigment), 24.1 parts of a pigment dispersant, 56.3 parts of ion-exchanged water, and 0.6 part of an antifoaming agent were mixed using a stirrer such as a disperser. Then, it was dispersed using a disperser filled with zirconia beads having a diameter of 0.05 mm at a volume filling rate of 70% as a medium to obtain coloring pigment dispersion 4.

[0223] (1-2) Preparation of a base coating composition

[0224] 143.3 parts of the acrylic resin emulsion of Production Example 1, 1.4 parts of dimethylaminoethanol, 35.6 parts of Cymel 370N (curing agent, solid content 87%), 16.7 parts of coloring pigment dispersion 4, 6.6 parts of other optical interference pigments relative to 100 parts by mass of resin solid content 3, 5 parts of the phosphoric acid group-containing organic compound of Production Example 2, 0.4 part of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of NOIGEN EA-207D (surfactant, solid content 55%), 3 parts of linoleic acid were added. After adding dimethylaminoethanol and adjusting the pH to 8.1, it was diluted with deionized water to prepare an aqueous base coating composition having a resin solid content concentration of 24.5% by mass.

[0225] (2) Formation of Multilayer Coating Film

[0226] Using the aqueous base coating composition obtained through the above-mentioned preparation, a coated article with a multilayer coating film was obtained according to the same steps as in Example 1.

[0227] [Comparative Example 4]

[0228] (1) Preparation of Base Coating Composition

[0229] (1-1) Preparation of Colored Pigment Dispersion 5

[0230] Using a stirrer such as a disperser, 34.5 parts of the water-soluble acrylic resin solution obtained in Production Example 3, 10.4 parts of carbon black (colored pigment), 18.6 parts of pigment dispersant, 36.0 parts of ion-exchanged water, and 0.5 part of antifoaming agent were mixed. Then, dispersion was carried out using a disperser filled with zirconia beads having a diameter of 0.05 mm at a volume filling rate of 70% as the medium to obtain Colored Pigment Dispersion 5.

[0231] (1-2) Preparation of Base Coating Composition

[0232] 133.3 parts of the acrylic resin emulsion of Production Example 1, 9.0 parts of dimethylaminoethanol, 35.6 parts of Cymel 370N (curing agent, solid content 87%), 43.2 parts of Colored Pigment Dispersion 5, 0.8 part of other optical interference pigments 3 relative to 100 parts by mass of resin solid content, 3.1 parts of other optical interference pigments 4 relative to 100 parts by mass of resin solid content, 5 parts of the phosphoric acid group-containing organic compound of Production Example 2, 0.4 part of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of NOIGEN EA-207D (surfactant, solid content 55%), and 3 parts of linoleic acid were uniformly dispersed. After adding dimethylaminoethanol and adjusting the pH to 8.1, it was diluted with deionized water to prepare an aqueous base coating composition having a resin solid content concentration of 24.5% by mass.

[0233] (2) Formation of Multilayer Coating Film

[0234] Using the aqueous base coating composition obtained through the above-mentioned preparation, a coated article with a multilayer coating film was obtained according to the same steps as in Example 1.

[0235] [Example 3]

[0236] (1) Preparation of First Base Coating Composition

[0237] (1-1) Preparation of Colored Pigment Dispersion 6

[0238] Using a stirrer such as a disperser, 78.3 parts of the water-soluble acrylic resin solution obtained in Production Example 3, 11.5 parts of perylene red (coloring pigment), 10.4 parts of carbon black (coloring pigment), 2.0 parts of Hostaperm Violet (coloring pigment), 1.4 parts of cyanine blue (coloring pigment), 34.3 parts of DISPEX ULTRA PA 4550 as a pigment dispersant, 81.3 parts of ion-exchanged water, and 1.1 parts of BYK-011 as an antifoaming agent were mixed. Subsequently, dispersion was carried out using a disperser filled with zirconia beads having a diameter of 0.05 mm at a volume filling rate of 70% as a medium, and a colored pigment dispersion 6 was obtained.

[0239] (1-2) Preparation of the first base coating composition

[0240] 122.1 parts of the acrylic resin emulsion of Production Example 1, 2.0 parts of dimethylaminoethanol, 35.6 parts of Cymel 370N (curing agent, solid content: 87%), 102.0 parts of the colored pigment dispersion 6, a paste containing a non-photointerference bright pigment in an amount of 2.1 parts relative to 100 parts by mass of resin solids (active ingredient: 60%), 5 parts of the phosphoric acid group-containing organic compound of Production Example 2, 0.4 part of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of NOIGEN EA-207D (surfactant, solid content: 55%), and 3 parts of linoleic acid were uniformly dispersed. After adding dimethylaminoethanol and adjusting the pH to 8.1, dilution was carried out with deionized water to prepare a first base coating composition having a resin solid content concentration of 19.9% by mass.

[0241] (2) Preparation of the second base coating composition

[0242] 143.3 parts of the acrylic resin emulsion of Production Example 1, 1.4 parts of dimethylaminoethanol, 35.6 parts of Cymel 370N (curing agent, solid content: 87%), a photointerference pigment in an amount of 30 parts by mass relative to 100 parts by mass of resin solids, 5 parts of the phosphoric acid group-containing organic compound of Production Example 2, 0.4 part of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of NOIGEN EA-207D (surfactant, solid content: 55%), and 3 parts of linoleic acid were uniformly dispersed. After adding dimethylaminoethanol and adjusting the pH to 8.1, dilution was carried out with deionized water to prepare an aqueous second base coating composition having a resin solid content concentration of 11.0% by mass.

[0243] (3) Formation of a multilayer coating film

[0244] In the same manner as in Example 1, an object to be coated having an electrodeposition coating film and an intermediate coating film was obtained.

[0245] Under the conditions of a room temperature of 23°C and a humidity of 68%, the above-prepared first base coating composition was spray-coated onto the object to be coated by air spraying so that the dry film thickness was 8 μm. After standing for 4 minutes, preheating was carried out at 80°C for 5 minutes.

[0246] Next, under the conditions of a room temperature of 23°C and a humidity of 68%, the above-prepared aqueous second base coating composition was spray-coated onto the object to be coated by air spraying in a wet-on-wet manner so that the dry film thickness was 4 μm. After standing for 4 minutes, preheating was carried out at 80°C for 5 minutes.

[0247] After the coated plate was allowed to cool to room temperature, it was operated in the same manner as in Example 1, and a transparent coating composition was spray-coated by air spraying to obtain a coated article having a multilayer coating film composed of a first base coating film, a second base coating film, and a transparent coating film.

[0248] [Example 4]

[0249] Except for using the following-prepared aqueous second base coating composition, a multilayer coating film was formed according to the same procedure as in Example 3.

[0250] (2) Preparation of the second base coating composition

[0251] (2-1) Preparation of the colored pigment dispersion 7

[0252] Using a stirrer such as a disperser, 38.9 parts of the water-soluble acrylic resin solution obtained in Production Example 3, 11.7 parts of perylene red (colored pigment), 14.0 parts of a pigment dispersant, 34.9 parts of ion-exchanged water, and 0.5 part of an antifoaming agent were mixed. Then, dispersion was carried out using a disperser filled with zirconia beads having a diameter of 0.05 mm at a volume filling rate of 70% as a medium to obtain the colored pigment dispersion 7.

[0253] (2-2) Preparation of the second base coating composition

[0254] 143.3 parts of the acrylic resin emulsion of Production Example 1, 1.4 parts of dimethylaminoethanol, 35.6 parts of Cymel 370N (curing agent, solid content 87%), 8.5 parts of the colored pigment dispersion 7, 29.5 parts by mass of an optical interference pigment relative to 100 parts by mass of the resin solid, 5 parts of the phosphoric acid group-containing organic compound of Production Example 2, 0.4 part of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of NOIGEN EA-207D (surfactant, solid content 55%), and 3 parts of linoleic acid were uniformly dispersed. After adding dimethylaminoethanol and adjusting the pH to 8.1, it was diluted with deionized water to prepare an aqueous second base coating composition having a resin solid content concentration of 11.0 mass%.

[0255] [Comparative Example 5]

[0256] (1) Preparation of the first base coating composition

[0257] (1-1) Preparation of the colored pigment dispersion 8

[0258] Using a stirrer such as a disperser, 72.6 parts of the water-soluble acrylic resin solution obtained in Production Example 3, 11.5 parts of perylene red (colored pigment), 10.4 parts of carbon black (colored pigment), 32.3 parts of a pigment dispersant, 70.2 parts of ion-exchanged water, and 1.0 part of an antifoaming agent were mixed. Subsequently, dispersion was carried out using a disperser filled with 0.05 mm zirconia beads at a volume filling rate of 70% as a medium to obtain the colored pigment dispersion 8.

[0259] (1-2) Preparation of the first base coating composition

[0260] 122.1 parts of the acrylic resin emulsion of Production Example 1, 2.0 parts of dimethylaminoethanol, 35.6 parts of Cymel 370N (curing agent, solid content 87%), 95.8 parts of the colored pigment dispersion 8, a paste containing a non-photointerference bright pigment (effective ingredient 60%) in an amount of 2.1 parts relative to 100 parts by mass of resin solid, 5 parts of the phosphoric acid group-containing organic compound of Production Example 2, 0.4 part of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of NOIGEN EA-207D (surfactant, solid content 55%), and 3 parts of linoleic acid were uniformly dispersed. After adding dimethylaminoethanol and adjusting the pH to 8.1, dilution was carried out with deionized water to prepare the first base coating composition having a resin solid content concentration of 19.9 mass%.

[0261] (2) Preparation of the second base coating composition

[0262] (2-1) Preparation of the colored pigment dispersion 9

[0263] Using a stirrer such as a disperser, 94.2 parts of the water-soluble acrylic resin solution obtained in Production Example 3, 10.1 parts of perylene red (colored pigment), 24.4 parts of anchor red (colored pigment), 1.9 parts of carbon black (colored pigment), 18.0 parts of a pigment dispersant, 55.9 parts of ion-exchanged water, and 0.5 part of an antifoaming agent were mixed. Subsequently, dispersion was carried out using a disperser filled with 0.05 mm zirconia beads at a volume filling rate of 70% as a medium to obtain the colored pigment dispersion 9.

[0264] (2-2) Preparation of the second base coating composition

[0265] 143.3 parts of the acrylic resin emulsion of Production Example 1, 1.4 parts of dimethylaminoethanol, 35.6 parts of Cymel 370N (curing agent, solid content 87%), 37.2 parts of color pigment dispersion 9, 15 parts by mass of other interference pigment 2 per 100 parts by mass of resin solid content, 5 parts of the organic compound containing a phosphoric acid group of Production Example 2, 0.4 parts of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of NOIGEN EA-207D (surfactant, solid content 55%), and 3 parts of linoleic acid were uniformly dispersed. Dimethylaminoethanol was added, the pH was adjusted to 8.1, and then diluted with deionized water to prepare an aqueous second base coating composition having a resin solid content concentration of 11.0% by mass.

[0266] (3) Formation of multilayer coatings

[0267] A multilayer coating film was formed in the same manner as in Example 3 except that the first and second base coating compositions were used.

[0268] [evaluate]

[0269] The following evaluations were performed using the multilayer coating films obtained in Examples and Comparative Examples. The evaluation results are shown in the following table.

[0270] (1) Spectral reflectance, brightness and chroma

[0271] The BYK-mac i spectrophotometer manufactured by BYK-Gardner was used to obtain the received light I at angles of -15 degrees, 15 degrees, and 45 degrees relative to the regular reflected light. 45 Spectral reflectance, L * C * h represents the chroma and brightness in the color system. 45 The light is incident from the clear coating film side at an angle of 45 degrees to the coated article. The average value of the five different samples is taken as the chromaticity C. * -15 , C * 15 , C * 45 , Brightness L * -15 , L * 15 .

[0272] (2) Coating appearance

[0273] The multilayer coating films obtained in Examples and Comparative Examples were viewed from an incident angle of 45° and a light acceptance angle of -15°, and then moved so that the light acceptance angle increased for visual observation and evaluated according to the following criteria.

[0274] Evaluation Criteria

[0275] A: Vividness is felt near the light-receiving angle of -15°. On the other hand, as the light-receiving angle increases, chroma is no longer felt, and the change in chroma is clearly recognized.

[0276] B: A certain degree of vividness is felt near the light-receiving angle of -15°. On the other hand, as the light-receiving angle increases, a certain degree of decrease in chroma is recognized.

[0277] C: Even when the light-receiving angle is increased starting from -15°, no change in chroma is recognized.

[0278] [Table 2]

[0279]

[0280]

[0281] [Table 3]

[0282]

[0283]

[0284] The coated films of the examples all have a large change in vividness in the high-brightness region and are recognized as almost achromatic in the front region.

[0285] For the coated films of Comparative Examples 1 and 5, if the light-receiving angle is increased starting from -15°, a certain degree of change in chroma is recognized in the high-brightness region, but the change is otherwise, and they are not recognized as achromatic in the front region.

[0286] For the coated films of Comparative Examples 2 to 4, almost no change in chroma is recognized in the high-brightness region.

[0287] The present disclosure includes the following aspects.

[0288] [1] A coating composition, which is a coating composition containing a film-forming resin and a pigment,

[0289] Based on the spectral reflectance of the reflected light R -15 of the L * C * chroma C in the LCH color system * -15 and based on the spectral reflectance of the reflected light R 15 of the L * C * chroma C in the LCH color system * 15 satisfy the following relationship, where the reflected light R -15Received the incident light I incident at an angle of 45 degrees with respect to the surface of the cured coating film of the above coating composition at an angle of -15 degrees with respect to the normal reflected light 45 of the reflected light, and this reflected light R 15 Received the above incident light I at an angle of 15 degrees with respect to the normal reflected light 45 of the reflected light,

[0290] C * -15 > C * 15 > 10, and

[0291] C * -15 -C * 15 > 20,

[0292] And, based on the spectral reflectance of the reflected light R 45 of the L * C * The chroma C in the LCh color system * 45 is 10 or less, and this reflected light R 45 Received the above incident light I at an angle of 45 degrees with respect to the normal reflected light 45 of the reflected light.

[0293] [2] The coating composition of the above [1], wherein the above chroma C * -15 is 50 or more.

[0294] [3] The coating composition of the above [1] or [2], wherein the above chroma C * 15 exceeds 10 and is 40 or less.

[0295] [4] The coating composition of any one of the above [1] to [3], wherein, based on the spectral reflectance of the above reflected light R -15 of the brightness L * -15 and based on the spectral reflectance of the above reflected light R 15 of the brightness L * 15 satisfies the following relationship:

[0296] L * -15 -L * 15 ≥ 10.

[0297] [5] The coating composition of any one of the above [1] to [4], wherein, in the wavelength range of 400 nm to 700 nm, the above reflected light R-15 The maximum spectral reflectance SR -15 and the above-mentioned reflected light R -15 spectral reflectance SR -15 the above-mentioned reflected light R at the wavelength at which the maximum is achieved 15 spectral reflectance SR 15 satisfy the following relationship:

[0298] SR -15 -SR 15 ≥20 (%)

[0299] [6] The coating composition according to any one of the above [1] to [5], wherein, in the wavelength range of 400 nm to 700 nm, the above-mentioned reflected light R -15 spectral reflectance SR -15 the wavelength W at which the maximum is achieved -15 and the above-mentioned reflected light R 15 spectral reflectance SR 15 the wavelength W at which the maximum is achieved 15 satisfy the following relationship:

[0300] │W -15 -W 15 │≥40 (nm).

[0301] [7] The coating composition according to any one of the above [1] to [6], wherein

[0302] the above-mentioned pigment contains a light-interfering flaky pigment

[0303] the above-mentioned light-interfering flaky pigment has:

[0304] a flaky reflective substrate having a first surface and a second surface opposite to the first surface;

[0305] a first layer containing at least one selected from silica, alumina, and metal fluorides; and

[0306] a second layer containing at least one selected from chromium, aluminum, silver, nickel, palladium, platinum, titanium, vanadium, cobalt, iron, tin, tungsten, molybdenum, rhodium, niobium, copper, and gold

[0307] at least two of the above-mentioned first layer and the second layer are alternately arranged on each of the first surface and the second surface with the first layer as the innermost layer

[0308] [8] A coated article, comprising:

[0309] a coated object, and

[0310] a cured coating film of the coating composition according to any one of the above [1] to [7] provided on the coated object

[0311] [9] The method for manufacturing a coated article, comprising: coating the coating composition according to any one of [1] to [7] above on an object to be coated and then curing it.

[0312] Industrial applicability

[0313] The coated article of the present invention is particularly suitable as an outer panel of an automobile body.

[0314] This application claims the priority based on Japanese Patent Application No. 2023-051982 filed on March 28, 2023, and the entire content thereof is incorporated herein by reference.

Claims

1. A coating composition, which is a coating composition containing a film-forming resin and a pigment, Based on the reflected light R -15 the chroma C * in the L * C * -15 h color system based on the spectral reflectance of the reflected light R 15 the chroma C * in the L * h color system based on the spectral reflectance of the reflected light R * 15 satisfies the following relationship, where The reflected light R -15 is the reflected light that receives the incident light I incident at an angle of 45 degrees with respect to the surface of the cured coating film of the coating composition at an angle of -15 degrees with respect to the specular reflection light 45 The reflected light R 15 is the reflected light that receives the incident light I at an angle of 15 degrees with respect to the specular reflection light 45 of the reflected light, C * -15 > C * 15 > 10, and C * -15 -C * 15 > 20, And, based on the reflected light R 45 the chroma C * in the L * Ch chromaticity system * 45 is 10 or less, and the reflected light R 45 is the reflected light that receives the incident light I 45 at an angle of 45 degrees with respect to the specularly reflected light wherein the pigment contains an optically interfering scaly pigment, and the optically interfering scaly pigment has: a scaly reflective substrate having a first surface and a second surface opposite to the first surface; a first layer containing at least one selected from silica, alumina, and metal fluorides; and a second layer containing at least one selected from chromium, aluminum, silver, nickel, palladium, platinum, titanium, vanadium, cobalt, iron, tin, tungsten, molybdenum, rhodium, niobium, copper, and gold, wherein at least two of the first layers and the second layers are alternately arranged on each of the first surface and the second surface with the first layer as the innermost layer.

2. The coating composition according to claim 1, wherein The above-mentioned chroma C * -15 is 50 or more.

3. The coating composition according to claim 1, wherein, The above-mentioned chroma C * 15 is more than 10 and 40 or less.

4. The coating composition according to claim 1, wherein, Based on the above-mentioned reflected light R -15 the luminance L of the spectral reflectance * -15 and the luminance L of the spectral reflectance based on the above-mentioned reflected light R 15 satisfy the following relationship: * 15 satisfy the following relationship: L * -15 -L * 15 ≥ 10.

5. The coating composition according to claim 1, wherein, In the wavelength range of 400 nm to 700 nm, the above-mentioned reflected light R -15 has a maximum spectral reflectance SR -15 and the spectral reflectance SR -15 of the above-mentioned reflected light R -15 at the wavelength at which the spectral reflectance SR 15 of the above-mentioned reflected light R reaches its maximum 15 satisfy the following relationship: SR -15 -SR 15 ≥20%.

6. The coating composition according to any one of claims 1 to 5, wherein, In the wavelength range of 400 nm to 700 nm, the above-described reflected light R -15 has a spectral reflectance SR -15 at the wavelength W -15 at which the spectral reflectance SR 15 of the above-described reflected light R 15 reaches a maximum satisfies the following relationship: 15 Satisfies the following relationship: │W -15 -W 15 │≥40 nm.

7. A coated article, which comprises: a substrate to be coated, and a cured coating film of the coating composition according to any one of claims 1 to 6 provided on the substrate to be coated.

8. A method for manufacturing a painted article, comprising: The coating composition according to any one of claims 1 to 6 is applied to the substrate to be coated and then cured.

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