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

Abstract

To provide a double-layer coating film which can be recognized as a black coating film and has a proper shade feeling.SOLUTION: A multilayer coating film comprising a first coating film, a second coating film and a clear coating film in this order, wherein the first coating film contains a black pigment, the second coating film contains a bright black scaly pigment and a black pigment, the chroma C * 15 in the L * C * h color system is 6 or less, and the lightness L * 110 in the L * C * h color system is 3 or less, A ratio L * 15 / L * 110 of a lightness L * 15 and a lightness L * 110 in an L * C * h color system is 9 or more and 24 or less, and a luster intensity Si15 is 2 or more and 10 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to multi-layer coatings, coated articles, and methods for making coated articles. [Background technology]

[0002] On the surface of a substrate, such as an automobile body, multiple coatings with various functions are sequentially formed to protect the substrate while also imparting a beautiful appearance and excellent design. A common method for forming such multiple coatings is to form a primer coating, such as an electrodeposition coating, on the substrate, which has excellent conductivity, and then sequentially form an intermediate coating and a topcoat coating as needed. Among these coatings, the topcoat coating, consisting of a base coating and a clear coating, in particular, significantly influences the appearance and design of the coating. In particular, in the case of automobiles, the appearance and design of the topcoat coating, consisting of a base coating and a clear coating, formed on the vehicle body, are extremely important.

[0003] The appearance of a paint film formed on an automobile is closely related to the automobile's appearance value, such as its luxurious feel. Furthermore, automobile buyers tend to seek automobiles with paint films that offer excellent design. Diversifying consumer preferences and a desire for originality are driving demand for more distinctive designs. For example, black paint films are an important color gamut that enjoys a certain share of the automotive paint market. Patent Document 1 discloses a multilayer paint film formation method that includes the steps of forming a colored paint film, a glossy paint film, and a clear paint film, and that can form a multilayer paint film with excellent jet blackness and glossiness. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 142639 Summary of the Invention [Problem to be solved by the invention]

[0005] While the multilayer coating film disclosed in Patent Document 1 is a coating film with excellent jet blackness and brilliance, recent consumer trends have demanded designs that are soft and not too flashy. However, many effect black colors using luminous materials use mica or glass flakes, which bring out the color of the luminous material or have a solid-like appearance. On the other hand, even if black is expressed using only aluminum flakes, there is a problem that the brightness increases due to strong reflection, making it difficult to recognize as black at first glance. Therefore, there was a need for technology that could achieve both a soft shadow effect that is not too solid-like and a brightness that is perceived as black without being too shiny.

[0006] The present disclosure has been made in view of the above, and aims to provide a multilayer coating film that is recognizable as black and has a moderate sense of shading. [Means for solving the problem]

[0007] In order to solve the above problems, the present disclosure provides the following aspects.

[0008] [1] A multi-layer coating film having a first coating film, a second coating film, and a clear coating film in this order, the first coating film contains a black pigment; the second coating film contains a brilliant black scale-like pigment and a black pigment, The L based on the spectral reflectance of the reflected light received at an angle of 15 degrees to the incident light incident on the surface of the multi-layer coating film at an angle of 45 degrees to the specular reflected light. * C * Saturation C in the h color system * 15 is 6 or less, The incident light incident on the surface of the multi-layer coating film at an angle of 45 degrees is reflected at an angle of 110 degrees relative to the specular reflection light. * C * Lightness L in the h color system * 110 is less than or equal to 3, The L based on the spectral reflectance of the reflected light received at an angle of 15 degrees to the incident light incident on the surface of the multi-layer coating film at an angle of 45 degrees to the specular reflected light.* C * Lightness L in the h color system * 15 and the lightness L * 110 The ratio of L * 15 / L * 110 is between 9 and 24, A light receiving unit is arranged in a direction perpendicular to the surface of the multi-layer coating film, and light is irradiated onto the surface of the multi-layer coating film at an angle of 15 degrees to the perpendicular direction, and the luminance intensity Si measured by the light receiving unit is 15 is between 2 and 10, Multi-layer coating.

[0009] [2] The bright black scale-like pigment contained in the second coating film is a scale-like pigment having a titanium sintered layer. [1] The multilayer coating film described in [1].

[0010] [3] The bright black scale-like pigment contained in the second coating film is a scale-like pigment having a titanium sintered layer on a mica flat plate substrate. [1] or [2].

[0011] [4] The content of the brilliant black scale pigment contained in the second coating film is 10% by mass or more and 30% by mass or less in terms of PWC, The content of the black pigment in the second coating film is 2% by mass or more and 12% by mass or less in terms of PWC. The multilayer coating film according to any one of [1] to [3].

[0012] [5] The content of the black pigment in the first coating film is 1.5% by mass or more and 5% by mass or less in terms of PWC. The multilayer coating film according to any one of [1] to [4].

[0013] [6] The average particle size of the glittering black scaly pigment contained in the second coating film is 5 to 14 μm. The multilayer coating film according to any one of [1] to [5].

[0014] [7] The object to be coated; A coated article comprising the multilayer coating film according to any one of [1] to [6] provided on the substrate.

[0015] [8] A method for coating a substrate with a first coating composition, a second coating composition, and a clear coating composition in that order to form a multi-layer coating film; the first coating composition contains a black pigment; the second coating composition contains a brilliant black scale-like pigment and a black pigment, The L based on the spectral reflectance of the reflected light received at an angle of 15 degrees to the incident light incident on the surface of the multi-layer coating film at an angle of 45 degrees to the specular reflected light. * C * Saturation C in the h color system * 15 is 6 or less, The incident light incident on the surface of the multi-layer coating film at an angle of 45 degrees is reflected at an angle of 110 degrees relative to the specular reflection light. * C * Lightness L in the h color system * 110 is less than or equal to 3, The L based on the spectral reflectance of the reflected light received at an angle of 15 degrees to the incident light incident on the surface of the multi-layer coating film at an angle of 45 degrees to the specular reflected light. * C * Lightness L in the h color system * 15 and the lightness L * 110 The ratio of L * 15 / L * 110 is between 9 and 24, A light receiving unit is arranged in a direction perpendicular to the surface of the multi-layer coating film, and light is irradiated onto the surface of the multi-layer coating film at an angle of 15 degrees to the perpendicular direction, and the luminance intensity Si measured by the light receiving unit is 15 is between 2 and 10, A method for manufacturing a coated article. [Effects of the Invention]

[0016] According to the present disclosure, it is possible to provide a multilayer coating film that is recognizable as black and has a moderate sense of shading. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present inventors have conducted research with the aim of developing a coating film with a paint color that is excellent in design. In this research, they have investigated a coating film that is recognizable as black but also has a moderate sense of shading, with the aim of developing a coating film with a unique appearance within the range of black, which is generally recognized as having a luxurious feel.

[0018] When aluminum flakes are used to impart a moderate shade to the paint film, the highlight brightness increases. Such a paint film has a so-called metallic gray color and is difficult to recognize as black. Furthermore, when mica is used, the shade tends to appear whitish, increasing the brightness at first glance or imparting saturation, making it difficult to recognize as a jet-black color. Furthermore, when high-reflectivity aluminum flakes or interference mica are used in small amounts to maintain a black shade, the desired design becomes overly shiny and grainy. Thus, it has been difficult to create a paint film that is recognizable as black while also having a moderate shade.

[0019] The present inventors conducted research aimed at solving the above problems. They discovered through experiments that by combining specific first and second coating films, it is possible to provide a multilayer coating film that is recognizable as black and has a moderate sense of shading, leading to the completion of the present invention. Below, the first coating composition that forms the first coating film and the second coating composition that forms the second coating film are described in order.

[0020] First paint composition The first coating film in the present disclosure is a cured coating film of a first coating composition, which is a coating composition containing a first coating film-forming resin and a black pigment.

[0021] The first coating composition contains a first film-forming resin. Examples of the first film-forming resin include acrylic resin, polyester resin, polyurethane resin, epoxy resin, fluororesin, and silicone resin. The first coating composition may be an aqueous coating composition or a solvent-based coating composition.

[0022] When the first coating composition is an aqueous coating composition, the first coating film-forming resin preferably contains, for example, an acrylic resin emulsion (including an acrylic silicone resin emulsion, an acrylic urethane resin emulsion, etc.), an acrylic resin dispersion (including an acrylic silicone resin dispersion, an acrylic urethane resin dispersion, etc.), a water-soluble acrylic resin, a polyester resin dispersion, a polyurethane resin dispersion, an epoxy resin dispersion, etc. These resins may be used alone or in combination of two or more. The resins can be prepared by methods commonly used by those skilled in the art. Commercially available products may also be used as the resins.

[0023] Preferred embodiments include, for example, an embodiment using either or both of an acrylic resin emulsion and a water-soluble acrylic resin, an embodiment using an acrylic resin emulsion, a water-soluble acrylic resin, and a polyester resin dispersion, and an embodiment using an acrylic resin emulsion, a water-soluble acrylic resin, and a polyurethane resin dispersion.

[0024] The acrylic resin emulsion can be prepared, for example, by emulsion polymerization of a mixture of α,β-ethylenically unsaturated monomers. Preferred α,β-ethylenically unsaturated monomers used in preparing the acrylic resin emulsion include, for example, (meth)acrylic acid esters, α,β-ethylenically unsaturated monomers having an acid group, and α,β-ethylenically unsaturated monomers having a hydroxyl group.

[0025] Examples of the (meth)acrylic acid ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, phenyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, dicyclopentadienyl (meth)acrylate, dihydrodicyclopentadienyl (meth)acrylate, etc. In this specification, (meth)acrylic acid ester refers to both acrylic acid ester and methacrylic acid ester.

[0026] Examples of α,β-ethylenically unsaturated monomers having an acid group include acrylic acid, methacrylic acid, crotonic acid, 2-acryloyloxyethyl phthalic acid, 2-acryloyloxyethyl succinic acid, ω-carboxy-polycaprolactone mono(meth)acrylate, isocrotonic acid, α-hydro-ω-((1-oxo-2-propenyl)oxy)poly(oxy(1-oxo-1,6-hexanediyl)), maleic acid, fumaric acid, itaconic acid, 3-vinylsalicylic acid, 3-vinylacetylsalicylic acid, 2-acrylamido-2-methylpropanesulfonic acid, p-hydroxystyrene, and 2,4-dihydroxy-4'-vinylbenzophenone.

[0027] Examples of α,β-ethylenically unsaturated monomers having a hydroxyl group include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, allyl alcohol, methallyl alcohol, and adducts thereof with ε-caprolactone. Among these, preferred are hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyethyl (meth)acrylate, and adducts thereof with ε-caprolactone.

[0028] The α,β-ethylenically unsaturated monomer mixture may further contain other α,β-ethylenically unsaturated monomers. Examples of other α,β-ethylenically unsaturated monomers include polymerizable amide compounds, polymerizable aromatic compounds, polymerizable nitriles, polymerizable alkylene oxide compounds, polyfunctional vinyl compounds, polymerizable amine compounds, α-olefins, dienes, polymerizable carbonyl compounds, polymerizable alkoxysilyl compounds, and other polymerizable compounds. The α,β-ethylenically unsaturated monomers can be selected from a variety of types as needed, depending on the purpose.

[0029] The acrylic resin emulsion can be prepared by emulsion polymerization of the above-mentioned α,β-ethylenically unsaturated monomer mixture. The emulsion polymerization is not particularly limited and can be carried out using a conventional method. Specifically, for example, an emulsifier is dissolved in an aqueous medium containing water or, if necessary, an organic solvent such as an alcohol or ether (e.g., dipropylene glycol methyl ether, propylene glycol methyl ether, etc.), and the above-mentioned α,β-ethylenically unsaturated monomer mixture and a polymerization initiator are added dropwise with heating and stirring. An α,β-ethylenically unsaturated monomer mixture previously emulsified using an emulsifier and water may also be added dropwise in the same manner.

[0030] The polymerization initiator and emulsifier may be those commonly used by those skilled in the art. If necessary, the molecular weight may be adjusted using a mercaptan such as lauryl mercaptan and a chain transfer agent such as α-methylstyrene dimer. The reaction temperature, reaction time, and the like may be appropriately selected within the ranges commonly used by those skilled in the art. The acrylic resin emulsion obtained by the reaction may be neutralized with a base, if necessary.

[0031] The acrylic resin emulsion preferably has a number average molecular weight of 3000 or less. The acrylic resin emulsion preferably has a hydroxyl value (solid content hydroxyl value) of 20 mgKOH / g or less and 180 mgKOH / g or less, and an acid value (solid content acid value) of 1 mgKOH / g or less and 80 mgKOH / g or less.

[0032] In this specification, the number average molecular weight is a value determined by the GPC method using polystyrene as a standard. In this specification, the acid value and hydroxyl value are values ​​calculated from the monomer composition used in the preparation based on the JIS standard.

[0033] The water-soluble acrylic resin can be prepared, for example, by solution polymerizing a monomer mixture containing an α,β-ethylenically unsaturated monomer that can be used to prepare the acrylic resin emulsion, and then dissolving the resulting monomer in water with a basic compound.The acrylic resin dispersion can be prepared, for example, by solution polymerizing a monomer mixture containing an α,β-ethylenically unsaturated monomer that can be used to prepare the acrylic resin emulsion, and then dispersing the resulting monomer with a basic compound.

[0034] The polyester resin dispersion can be prepared, for example, by condensing a polyhydric alcohol component with a polybasic acid component and dispersing the resulting mixture with a basic compound. The polyurethane resin dispersion can be prepared, for example, by polymerizing a polyol compound, a compound having an active hydrogen group and a hydrophilic group in the molecule, and an organic polyisocyanate, optionally using a chain extender and a polymerization terminator, and then dissolving or dispersing the resulting polymer in water.

[0035] When the first coating composition is an aqueous coating composition, it is preferable to use a curing agent that reacts with the first film-forming resin. Such a curing agent is a film-forming component that reacts with the first film-forming resin to form a coating film. Examples of curing agents that can be used include melamine resins, blocked isocyanate compounds, epoxy compounds, aziridine compounds, carbodiimide compounds, oxazoline compounds, and metal ions. These may be used alone or in combination with two or more. The above components can be prepared by methods commonly used by those skilled in the art. Commercially available products may also be used as the above components. It is more preferable to use either or both of a melamine resin and a blocked isocyanate compound as the curing agent.

[0036] The melamine resin may be a water-soluble melamine resin and / or a water-insoluble melamine resin. The melamine resin has a structure in which hydrogen atoms or substituents (such as alkyl ether groups and methylol groups) are bonded to the periphery of a melamine nucleus (triazine nucleus) via three nitrogen atoms. The melamine resin is generally composed of a polynuclear compound in which multiple melamine nuclei are bonded to each other. However, the melamine resin may also be a mononuclear compound consisting of a single melamine nucleus.

[0037] Commercially available melamine resins may be used. Specific examples of commercially available products include the Cymel series (trade name) manufactured by Allnex, specifically Cymel 202, Cymel 204, Cymel 211, Cymel 232, Cymel 235, Cymel 236, Cymel 238, Cymel 250, Cymel 251, Cymel 254, Cymel 266, Cymel 267, Cymel 272, Cymel 285, Cymel 301, Cymel 303, Cymel 325, Cymel 327, Cymel 350, Cymel 370, Cymel 701, Cymel 703, and Cymel 1141; and the U-Ban (trade name) series manufactured by Mitsui Chemicals, Inc. These may be used alone or in combination of two or more.

[0038] Blocked isocyanate compounds can be prepared by adding a blocking agent having an active hydrogen to a polyisocyanate such as trimethylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, etc. In such blocked isocyanate resins, the blocking agent dissociates upon heating to generate isocyanate groups, which react with functional groups in the resin component to cure.

[0039] The amount of curing agent is preferably 10 to 80 mass %, more preferably 15 to 60 mass %, based on the paint resin solids mass (the solids mass of the film-forming components including the film-forming resin and curing agent).

[0040] The first coating composition contains a black pigment. Suitable examples of the black pigment include carbon black, graphite, iron black, composite metal oxides such as iron chromium and bismuth manganese, perylene-based black pigments, and azomethiazo-based pigments.

[0041] The black pigment is preferably contained in the first coating film in a PWC (Pigment Weight Concentration) range of 1.5% by mass to 5% by mass.

[0042] The first coating composition may contain other pigments in addition to the black pigment, as needed, provided that the amount of these other pigments does not impair the performance of the first coating film. Examples of other pigments include color pigments and extender pigments. Examples of color pigments include various inorganic and organic color pigments. Examples of color pigments include blue pigments such as Prussian blue, ultramarine blue, cobalt blue, copper phthalocyanine blue, and indanthrone blue; Yellow pigments such as yellow lead, synthetic yellow iron oxide, bismuth vanadate, titanium yellow, zinc yellow, ochre, monoazo yellow, disazo yellow, isoindolinone yellow, metal complex azo yellow, quinophthalone yellow, and benzimidazolone yellow; Red pigments such as iron oxide, transparent iron oxide, monoazo red, quinacridone red, azo lake (Mn salt), perylene red, perylene maroon; Orange pigments such as quinacridone magenta, anthanthrone orange, dianthrachinonyl red, pyrazolone orange, benzimidazolone orange, and diketopyrrolopyrrole chrome vermilion; Green pigments such as chlorinated phthalocyanine green and brominated phthalocyanine green; Violet pigments such as dioxazine violet and perylene violet; White pigments such as titanium dioxide; Examples include:

[0043] Examples of extender pigments include calcium carbonate, barium sulfate, clay, talc, etc. The pigments may further contain an anti-rust pigment, if necessary.

[0044] If the first coating composition is an aqueous coating composition, the aqueous first coating composition may contain, in addition to the above components, additives commonly used by those skilled in the art, such as surface conditioners, viscosity control agents, thickeners, antioxidants, UV inhibitors, and antifoaming agents. For example, the use of a viscosity control agent can impart thixotropy and adjust coating workability. Examples of viscosity control agents include crosslinked or non-crosslinked resin particles, polyamide-based agents such as swollen dispersions of fatty acid amides, amide-based fatty acids, and phosphate salts of long-chain polyaminoamides, polyethylene-based agents such as colloidal swollen dispersions of polyethylene oxide, and organic bentonite-based agents such as organic acid smectite clay and montmorillonite. When these additives are used, they can be used in amounts commonly used by those skilled in the art.

[0045] The first aqueous coating composition may further contain a phosphoric acid group-containing organic compound in addition to the above components, if necessary.

[0046] The above-mentioned aqueous first coating composition may contain water as a solvent, and optionally a water-soluble or water-miscible organic solvent.

[0047] The first aqueous coating composition can be produced by a method commonly used by those skilled in the art, such as kneading and dispersing the first film-forming resin, black pigment, curing agent, and other components and additives as needed using a disperser, homogenizer, kneader, etc. In the production method, it is preferable to prepare a paste containing the black pigment and an optional pigment dispersant in advance and then mix them together. Commercially available pigment dispersants can be used as the pigment dispersant.

[0048] When the first coating composition is a solvent-based coating composition, examples of the first coating film-forming resin include acrylic resins, polyester resins (including urethane-modified polyester resins), etc. These resins may be used alone or in combination of two or more.

[0049] The acrylic resin can be prepared, for example, by solution polymerization of a monomer mixture containing an α,β-ethylenically unsaturated monomer. The acrylic resin preferably has a number average molecular weight of 1,000 to 20,000. The acrylic resin also preferably has an acid value (solid content acid value) of 1 to 80 mg KOH / g, more preferably 10 to 45 mg KOH / g. The hydroxyl value (solid content hydroxyl value) is preferably 10 to 200 mg KOH / g.

[0050] Commercially available acrylic resins may be used, such as the Dianale HR series manufactured by Mitsubishi Rayon Co., Ltd.

[0051] The amount of acrylic resin is preferably 30 to 80 mass %, more preferably 35 to 70 mass %, based on the paint resin solid content mass (solid content mass of the coating film-forming components).

[0052] The polyester resin may be, for example, a hydroxyl group-containing polyester resin, which can be prepared by polycondensation of an acid component such as a polycarboxylic acid and / or an acid anhydride with a polyhydric alcohol.

[0053] When the first coating composition is a solvent-based coating composition, it is preferable to use a curing agent that reacts with the first coating film-forming resin. Examples of curing agents that can be used include melamine resins and blocked isocyanate compounds. These may be used alone or in combination with two or more. The above components can be prepared by methods commonly used by those skilled in the art. Commercially available products may also be used as the above components.

[0054] The curing agent preferably contains a melamine resin. The melamine resin is not particularly limited, and examples include methylated melamine resin, butylated melamine resin, and mixed methyl-butyl melamine resin. Examples include the Cymel series available from Allnex and the U-Van series available from Mitsui Chemicals. The amount of melamine resin is preferably 10 to 50% by mass, more preferably 15 to 40% by mass, based on the solids mass of the paint resin (the solids mass of the film-forming components including the film-forming resin and curing agent).

[0055] The curing agent preferably further contains a blocked isocyanate compound. The blocked isocyanate compound can be prepared by addition reaction of a polyisocyanate with a blocking compound such as a compound having an active methylene group, a ketone compound, or a caprolactam compound. Commercially available blocked isocyanate compounds may be used. Examples of commercially available blocked isocyanate compounds include the Duranate series manufactured by Asahi Kasei Corporation and the Sumidur series manufactured by Sumika Covestro Urethane Co., Ltd.

[0056] The amount of the blocked isocyanate compound contained in the first coating composition is preferably 10 to 30 mass %, more preferably 15 to 25 mass %, based on the paint resin solid content mass (the solid content mass of the coating film-forming components including the coating film-forming resin and curing agent).

[0057] The solvent-based first coating composition contains the first coating film-forming resin and a black pigment. The black pigment may be the same as that described above. In addition to the above components, the solvent-based first coating composition may contain additives commonly used by those skilled in the art, such as a curing catalyst, a surface conditioner, an ultraviolet absorber, and an antioxidant.

[0058] The solids concentration and viscosity of the solvent-based first coating composition can be appropriately adjusted by diluting it with an organic solvent at the time of application. Examples of organic solvents that can be used include ester-based solvents, ether-based solvents, alcohol-based solvents, ketone-based solvents, aliphatic hydrocarbon-based solvents, and aromatic solvents.

[0059] The solvent-based first coating composition may further contain a phosphoric acid group-containing organic compound in addition to the above components, if necessary.

[0060] The solvent-based first coating composition can be produced by a method commonly used by those skilled in the art, such as kneading and dispersing the first coating film-forming resin, curing agent, pigment, phosphate group-containing organic compound, and additives using a disperser, homogenizer, kneader, etc. In the above production method, it is preferable to previously prepare a paste containing, for example, a black pigment and, if necessary, a pigment dispersant, and then mix them.

[0061] Second paint composition The second coating film in this disclosure is a cured coating film of a second coating composition. The second coating composition is a coating composition containing a second coating film-forming resin, a shiny black scale-like pigment, and a black pigment. Like the first coating composition, the second coating composition may be an aqueous coating composition or a solvent-based coating composition. Such a second coating composition can be prepared by the same procedure as for the first coating composition.

[0062] The second film-forming resin can be the same as the first film-forming resin. The first and second film-forming resins may have the same resin composition or different resin compositions.

[0063] The second coating composition contains a shiny black scaly pigment. The shiny black scaly pigment is preferably a scaly pigment having a titanium sintered layer, and more preferably a scaly pigment having a titanium sintered layer on a mica flat plate substrate. Instead of the mica flat plate substrate, the scaly pigment may use an aluminum flat plate substrate or a glass flat plate substrate. The shiny black scaly pigment exhibits brilliance due to the substrate such as the mica flat plate substrate, and the titanium sintered layer provides a black color.

[0064] The titanium sintered layer has a composition satisfying TiOx (0.50≦x≦1.90). This allows the titanium sintered layer itself to exhibit a black color. The titanium sintered layer is a layer that exhibits a black color without completely concealing the brilliance of a substrate such as a mica flat substrate. The X value of TiOx more preferably satisfies 1.00≦x≦1.90, and even more preferably 1.10≦x≦1.90. The composition of the titanium sintered layer can be determined by observing the titanium sintered layer using a powder X-ray diffraction analyzer and performing quantitative analysis using the RIR (Reference Intensity Ratio) method.

[0065] The thickness of the titanium sintered layer is preferably 50 to 1000 nm, more preferably 100 to 600 nm. If the thickness is less than 50 nm, the titanium sintered layer may not sufficiently absorb visible light, which may make it difficult to achieve a highly attractive black color. If the thickness is more than 1000 nm, the titanium sintered layer may excessively absorb visible light, which may prevent the gloss of a substrate such as a mica flat plate substrate from being fully exhibited.

[0066] The titanium sintered layer preferably uniformly covers the entire substrate and has a uniform thickness, but may be partially missing or may have an uneven thickness as long as the effects of the present disclosure are achieved. Multiple titanium sintered layers may be present in the bright black scaly pigment, and in that case, the composition and thickness of each titanium sintered layer preferably satisfy the above conditions, but the respective compositions and thicknesses may be the same or different.

[0067] The bright black scaly pigment may have an amorphous silicon compound layer in addition to the titanium sintered layer. The amorphous silicon compound layer is made of at least one of silicon oxide, silicon hydroxide, and silicon hydrate. By having the amorphous silicon compound layer on the bright black scaly pigment, the water resistance of the bright black scaly pigment can be improved.

[0068] The thickness of the amorphous silicon compound layer is preferably 10 to 1000 nm, which allows the brilliant black scaly pigment to maintain both sufficient water resistance and good hiding power at a high level.

[0069] The amorphous silicon compound layer preferably uniformly covers the entire substrate and has a uniform thickness, but may be partially missing or have an uneven thickness as long as the effects of the present disclosure are achieved. A plurality of amorphous silicon compound layers may be present in the bright black scaly pigment, and in this case, the composition and thickness of each amorphous silicon compound layer preferably satisfy the above conditions, but the respective compositions and thicknesses may be the same or different.

[0070] The bright black scaly pigment may have layers other than the titanium sintered layer and the amorphous silicon compound layer. For example, it may have a base layer made of at least one of oxide, hydroxide, and hydrate of molybdenum (Mo) and / or phosphorus (P), or a resin layer. The base layer can improve the water resistance of the bright black scaly pigment and can also serve as a starting point for the growth of other layers on the base layer.

[0071] The resin layer can improve the chemical resistance of the brilliant black scaly pigment and also improve the adhesion between the resin contained in the second coating composition and the brilliant black scaly pigment, thereby improving the physical properties of the second coating film. In order to achieve the above effects, the resin layer is preferably the outermost layer of the brilliant black scaly pigment. The coating amount of the resin layer is preferably 0.5 to 100 parts by mass, and more preferably 1 to 50 parts by mass, relative to the substrate.

[0072] A suitable resin for the resin layer is a copolymer resin obtained by copolymerizing two or more polymerizable monomers, such as reactive monomers having a carboxyl group and / or a phosphate group, trifunctional or higher polyfunctional acrylic ester monomers, and polymerizable monomers having a benzene nucleus.

[0073] The above-mentioned lustrous black scaly pigment can be produced by forming a titanium sintered layer on the surface of a substrate, which is the object to be coated. When an amorphous silicon compound layer is interposed between the substrate and the titanium sintered layer, the titanium sintered layer is formed by reducing a titanium dioxide layer formed by hydrolysis. The reduction treatment is carried out by firing the substrate on which the titanium dioxide layer is formed in a reducing atmosphere. When an amorphous silicon compound layer is not interposed between the substrate and the titanium sintered layer, the titanium sintered layer is formed by reducing a titanium dioxide layer formed by a sol-gel process in the same manner as above.

[0074] The lustrous black scaly pigment may be a commercially available product, such as the Black Diamond (registered trademark) series manufactured by Ako Kasei Co., Ltd.

[0075] The above-mentioned lustrous black scaly pigment preferably has an average particle size (D50) of 5 to 14 μm, which allows for the second coating film to have an appropriate graininess. The above-mentioned average particle size is more preferably 7 to 12 μm, and even more preferably 8 to 11 μm.

[0076] The shiny black scaly pigment is a pigment having a major axis and a minor axis. In the second coating film, the shiny black scaly pigment is preferably oriented so that the major axis direction is approximately perpendicular to the film thickness direction. The orientation direction of the shiny black scaly pigment can be controlled by the film thickness of the second coating film and the nonvolatile content (%) of the second coating composition, etc.

[0077] The second coating composition contains a black pigment. The black pigment contained in the second coating composition can be the same as the black pigment contained in the first coating composition.

[0078] The shiny black scale-like pigment is preferably contained in the second coating film at a PWC (Pigment Weight Concentration) of 10% by mass to 30% by mass. The black pigment is preferably contained in the second coating film at a PWC (Pigment Weight Concentration) of 2% by mass to 12% by mass. By containing the shiny black scale-like pigment and the black pigment in the second coating film at the above-mentioned contents, the pigments can be oriented without gaps within the coating film, and a coating film that is recognizable as black but has an appropriate sense of shadow can be formed.

[0079] The second coating composition may contain pigments other than the pigments described above. Examples of other pigments include the extender pigments and anti-rust pigments exemplified in the first coating composition. Examples of extender pigments include calcium carbonate, barium sulfate, clay, and talc.

[0080] Multi-layer coating The multilayer coating film of the present disclosure is a coating film having, in this order: a first coating film which is a cured coating film of the first coating composition; a second coating film which is a cured coating film of the second coating composition; and a clear coating film.

[0081] In forming the multilayer coating film of the present disclosure, the substrate to which the coating composition is applied is not particularly limited, and examples thereof include metals, plastics, and foams. The coating composition is particularly advantageous for use on metals and cast products, and is particularly suitable for use on metals that can be electrodeposited. Examples of such metals include iron, copper, aluminum, tin, zinc, and alloys containing these metals. These substrates may also be molded products. Specific examples of molded products include automobile bodies and parts thereof, such as passenger cars, trucks, motorcycles, and buses. It is more preferable that the metal substrates be chemically treated with a phosphate-based chemical conversion treatment agent, a zirconium-based chemical conversion treatment agent, or the like before electrodeposition coating. It is preferable that a cured electrodeposition coating film be formed on a substrate that has been chemically treated as needed. Either cationic or anionic electrodeposition coating compositions can be used to form the cured electrodeposition coating film. Using a cationic electrodeposition coating composition as the electrodeposition coating composition is preferable because it allows for the formation of a coating film with superior corrosion resistance.

[0082] If necessary, the substrate may further have an intermediate coating film formed on the cured electrodeposition coating film. An intermediate coating composition is used to form the intermediate coating film. Examples of intermediate coating compositions that can be used include coating compositions containing a film-forming resin, a curing agent, various organic and / or inorganic coloring components, and extender pigments. The film-forming resin and curing agent are not particularly limited, and specifically, the film-forming resins and curing agents listed above for the aqueous coating composition can be used. From the perspective of various performance characteristics of the resulting intermediate coating film, a combination of an acrylic resin and / or polyester resin with an amino resin and / or isocyanate is preferably used as the film-forming resin in the intermediate coating composition.

[0083] Examples of methods for forming a coating film using the first and second coating compositions include the following methods. A method in which the first and second coating compositions are applied sequentially to a substrate, followed by application of a clear coating composition. In this type of application, the first coating composition may be applied and heat-cured, and then the second coating composition may be applied and heat-cured. Alternatively, the first coating composition may be applied, and while the applied coating is still uncured, the second coating composition may be applied wet-on-wet, followed by heat-curing. In the wet-on-wet application, preheating may be performed between coats as needed. Alternatively, the first and second coating compositions may be applied sequentially and dried at room temperature. A clear coating composition may then be applied to the second coating film obtained by applying the second coating composition to form a clear coating film. A method in which a first coating composition, a second coating composition, and a clear coating composition are sequentially applied to a substrate in a wet-on-wet manner. Specifically, this coating method involves sequentially applying the first coating composition, the second coating composition, and a clear coating in a wet-on-wet manner to form uncured first coating films, second coating films, and clear coating films, and then simultaneously heat-curing these uncured coating films. In the wet-on-wet coating method, preheating may be performed between coats as needed.

[0084] The first and second coating compositions can be applied to the substrate by a method commonly used in the coating field, such as air spray coating, airless spray coating, electrostatic spray coating, multi-stage coating (preferably two-stage coating) using air electrostatic spray coating, or a combination of air electrostatic spray coating and a rotary atomizer-type electrostatic coater.

[0085] The first coating composition is preferably applied so that the thickness of the first coating film after curing is within the range of 5 to 15 μm. The lower limit of the film thickness may be 5.5 μm. The upper limit of the film thickness may be 13 μm or 11 μm. The second coating composition is preferably applied so that the thickness of the second coating film after curing is within the range of 2 to 10 μm. The lower limit of the thickness may be 2.5 μm. The upper limit of the thickness may be 8 μm or 6 μm.

[0086] By setting the film thickness of the first coating film and the second coating film after curing within the above range, the jet blackness of the first coating film can be ensured, and the color of the first coating film can be moderately transparent through the second coating film. Note that if the film thickness of the second coating film after curing is thicker than the film thickness of the first coating film after curing, the brightness of the multi-layer coating film may become too high. For this reason, it is preferable that the film thickness of the first coating film after curing is thicker than the film thickness of the second coating film after curing.

[0087] The heating temperature and time when the first and second coating compositions are applied and heat-cured can be appropriately selected depending on the composition of the coating composition (water-based or solvent-based) and the type of substrate. The heating temperature can be appropriately selected, for example, in the range of 80 to 180°C, preferably 100 to 160°C. The heating time can be appropriately selected, for example, in the range of 5 to 60 minutes, preferably 10 to 30 minutes.

[0088] The clear coating composition is not particularly limited, and examples thereof include solvent-based, water-based, and powder-based clear coating compositions.

[0089] Preferred examples of the above-mentioned solvent-based clear coating composition include, from the viewpoints of transparency or acid etching resistance, a combination of an acrylic resin and / or a polyester resin with an amino resin and / or an isocyanate, or an acrylic resin and / or a polyester resin having a carboxylic acid / epoxy curing system.

[0090] Examples of the water-based clear coating composition include those containing the film-forming resins listed as examples of the solvent-based clear coating composition above, neutralized with a base to make them water-based. This neutralization can be carried out by adding a tertiary amine such as dimethylethanolamine or triethylamine before or after polymerization.

[0091] These solvent-based and water-based clear coating compositions preferably contain a viscosity control agent to ensure coating workability. Viscosity control agents that generally exhibit thixotropy can be used. Examples of viscosity control agents that can be used include those listed for the water-based coating compositions. Additionally, additives commonly used in the coating field may be included as needed.

[0092] As the powder-type clear coating composition, for example, powder coating compositions commonly used in the coating field, such as thermoplastic powder coating compositions and thermosetting powder coating compositions, can be used. Among these, thermosetting powder coating compositions are preferred in terms of coating film properties, etc. Specific examples of thermosetting powder coating compositions include epoxy-based, acrylic-based, and polyester-based powder clear coating compositions.

[0093] The application of the clear coating composition can be carried out using a coating method known to those skilled in the art in accordance with the application form of the clear coating composition. The dry film thickness of the clear coating film formed by applying the above-mentioned clear coating composition is generally preferably 10 to 80 μm, more preferably 20 to 60 μm.

[0094] A cured clear coating film can be formed by heat-curing the uncured clear coating film obtained by applying the clear coating composition. When the clear coating composition is applied onto an uncured second base coating film, the uncured coating film is heat-cured by heating. From the viewpoint of curability and the physical properties of the resulting multilayer coating film, the heat-curing temperature is preferably set to 80 to 180°C, and more preferably 120 to 160°C. The heat-curing time can be set as desired depending on the temperature. Heat-curing conditions include, for example, heating at a heat-curing temperature of 120 to 160°C for 10 to 30 minutes. Depending on the type of coating composition, the coating composition may be applied, then dried at room temperature to form a coating film, and then, for example, a reaction-curing clear coating composition may be applied to provide a clear coating film.

[0095] The multi-layer coating film of the present disclosure comprises: L based on the spectral reflectance of incident light incident at a 45-degree angle on the surface of a multi-layer coating, and reflected light received at a 15-degree angle relative to the specular reflection. * C * Saturation C in the h color system * 15 is 6 or less, L based on the spectral reflectance of incident light incident at a 45-degree angle on the surface of a multi-layer coating, and reflected light received at an angle of 110 degrees relative to the specular reflection. * C * Lightness L in the h color system * 110 is less than or equal to 3, L based on the spectral reflectance of incident light incident at a 45-degree angle on the surface of a multi-layer coating, and reflected light received at a 15-degree angle relative to the specular reflection. * C * Lightness L in the h color system * 15 and the lightness L * 110 The ratio of L * 15 / L * 110 is between 9 and 24, The light receiving unit is placed perpendicular to the surface of the multi-layer coating film, and light is irradiated onto the surface of the multi-layer coating film at an angle of 15 degrees to the perpendicular direction, and the brightness intensity Si measured by the light receiving unit is 15 is between 2 and 10, This is subject to the condition that:

[0096] Above lightness L * L * C * This is a parameter in the h color system and can be calculated in accordance with JIS Z8729. * C * The h color system is a color system established by the International Commission on Illumination and is described in Section 4.2 of CIE Publication 15.2 (1986). * C * In the h color system, L * represents lightness, and C * represents the saturation, and h represents the hue angle. * As the value increases, the brightness of the measured material increases, and as the value decreases, the brightness increases. * means that the brightness of the measured substance increases as the value increases, and the darkness increases as the value decreases. * and saturation C * can be measured using a commercially available multi-angle spectrophotometer. An example of a multi-angle spectrophotometer is BYK-maci (manufactured by BYK).

[0097] Above saturation C * 15 , brightness L * 110 , and lightness L * 15 In this specification, the incident light and reflected light refer specifically to the reflected light at positions 15 degrees and 110 degrees, respectively, in the direction of the incident angle from the specularly reflected light of light irradiated at an angle of 45 degrees onto the multilayer coating film, with the position of the specularly reflected light being set at 0 degrees.

[0098] The above brightness intensity Si 15Specifically, the sparkle intensity (S) can be calculated from an image obtained by placing, for example, an imaging means as a light receiving unit perpendicular to the surface of the multilayer coating film, irradiating the surface of the multilayer coating film with light at an angle of 15 degrees from the perpendicular direction and photographing the surface of the multilayer coating film with the imaging means. Specifically, the image obtained by the imaging means is analyzed using an image analysis algorithm that uses a brightness level histogram, and two-dimensional analysis is performed to calculate the light brightness parameter, which can be calculated as sparkle intensity (S value). A CCD chip is used as the imaging means.

[0099] The above brightness intensity Si 15 can be calculated, for example, by measuring using the above-mentioned multi-angle spectrophotometer.

[0100] In this specification, the chroma C of the multi-layer coating film * , brightness L * The measurements of the brilliance intensity Si and the gloss intensity Si refer to values ​​measured using a multilayer coating film composed of a cured coating film of the first coating composition, a cured coating film of the second coating composition, and a clear coating film. More specifically, the first coating composition is spray-coated on a steel plate coated with a cationic electrodeposition coating composition, on which a medium gray cured intermediate coating film has been formed, followed by wet-on-wet spray-coating of the second coating composition, and then wet-on-wet spray-coating of the clear coating composition to a dry film thickness of 35 μm, and then the uncured three-layer coating film is heat-cured at 140°C for 30 minutes, and the measurements are made using the resulting multilayer coating film.

[0101] In the multilayer coating film of the present disclosure, the chroma C * 15 The condition is that the saturation C is 6 or less. * 15 is preferably 3 or less.

[0102] In the multi-layer coating film of the present disclosure, the above lightness L * 110 The condition is that the value of the above lightness L is 3 or less. * 110The multi-layer coating film preferably has a chroma C of 1.6 or less. * 15 and lightness L * 110 is within the above range and the coating film is recognizable as black.

[0103] In the multi-layer coating film of the present disclosure, the lightness L * 15 and the lightness L * 110 The ratio of L * 15 / L * 110 One of the characteristics of the multi-layer coating film is that the L * 15 / L * 110 is within the above range, and one of the features of the coating film is that it has a smooth shading effect from highlights to shades and has an appropriate shading effect. * 15 / L * 110 If is less than 9, it will have a flat appearance, and L * 15 / L * 110 If the value exceeds 24, the contrast will be too strong and the appearance will be metallic, and neither of them will be able to achieve the appropriate sense of shadow. * 15 / L * 110 is preferably 12 or more and 19 or less.

[0104] In the multi-layer coating film of the present disclosure, the brilliance intensity Si 15 The condition is that the brightness intensity Si is 2 or more and 10 or less. 15 is an index showing the intensity of brilliance, and the higher the value, the stronger the brilliance. The above multi-layer coating film is recognized as having a certain intensity of brilliance (moderate graininess) under so-called highlight light receiving angle conditions. Brilliance intensity Si 15 is preferably 4 or more and 8 or less.

[0105] As described above, the multilayer coating film of the present disclosure is a coating film that can be recognized as black, yet has an original design with a moderate sense of shading.

[0106] The preferred embodiments of the present disclosure have been described above. The present disclosure is not limited to the above embodiments, and can be modified within the scope of the present disclosure. [Example]

[0107] Examples of the present disclosure will be described below, but the present disclosure is not limited to these examples. In the examples, "parts" and "%" are by mass unless otherwise specified.

[0108] Production Example 1: Production of acrylic resin emulsion (film-forming resin) 633 parts of deionized water was added to a reaction vessel, and the temperature was raised to 80°C while mixing and stirring in a nitrogen stream. Next, a monomer emulsion consisting of 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), and 105.00 parts by mass of hydroxyethyl methacrylate (HEMA), 25.00 parts by mass of Aqualon HS-10 (polyoxyethylene alkylpropenylphenyl ether sulfate, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), 25.00 parts by mass of Adeka Reasoap NE-20 (α-[1-[(allyloxy)methyl]-2-(nonylphenoxy)ethyl]-ω-hydroxyoxyethylene, manufactured by ADEKA Corporation), and 400 parts by mass of deionized water, and an initiator solution consisting of 1.2 parts by mass of ammonium persulfate and 500 parts by mass of deionized water were added dropwise to the reaction vessel in parallel over 1.5 hours. After the dropwise addition was completed, the mixture was aged at the same temperature for 1 hour. Further, at 80°C, a second-stage monomer mixture of 53.65 parts by weight of styrene (ST), 178.96 parts by weight of methyl methacrylate (MMA), 75.94 parts by weight of n-butyl acrylate (BA), 64.45 parts by weight of 2-ethylhexyl acrylate (2-EHA), 105.00 parts by weight of hydroxyethyl methacrylate (HEMA), and 22 parts by weight of acrylic acid, a monomer emulsion of 10 parts of Aqualon HS-10 and 250 parts of deionized water, and an initiator solution of 3.0 parts of ammonium persulfate and 500 parts of deionized water were added dropwise to the reaction vessel over 1.5 hours. After completion of the dropwise addition, the mixture was aged at the same temperature for 2 hours. The mixture was then cooled to 40°C and filtered through a 400-mesh filter. 100 parts of deionized water and 1.6 parts of dimethylaminoethanol were then added to adjust the pH to 6.5, yielding an acrylic resin emulsion with an average particle size of 150 nm, a nonvolatile content of 35%, a solid acid value of 20 mgKOH / g, and a hydroxyl value of 100 mgKOH / g.

[0109] Production Example 2: Production of phosphoric acid group-containing organic compound A 1-liter reaction vessel equipped with a stirrer, temperature controller, and condenser was charged with 40 parts of ethoxypropanol, and 40 parts of a solution of 4 parts of styrene, 35.96 parts of n-butyl acrylate, 18.45 parts of ethylhexyl methacrylate, 13.92 parts of 2-hydroxyethyl methacrylate, 7.67 parts of methacrylic acid, 20 parts of ethoxypropanol, 40 parts of a solution of 20 parts of Hosmer PP (acid phosphooxyhexa(oxypropylene) monomethacrylate manufactured by Unichemical Co.), and 121.7 parts of a monomer solution consisting of 1.7 parts of azobisisobutyronitrile was added dropwise at 120 ° C. for 3 hours, and stirring was continued for another 1 hour. The resulting phosphate group-containing organic compound had an acid value of 105 mg KOH / g, a phosphate value of 55 mg KOH / g, a hydroxyl value of 60 mg KOH / g, a number average molecular weight of 6000, and a nonvolatile content of 63%.

[0110] Example 1 Preparation of the first coating composition Pigment dispersion paste A pigment dispersion paste was obtained by mixing and dispersing 3 parts of black pigment R5000 (Laven 5000), 18.6 parts of pigment dispersant Dispex® Ultra PA 4550 (BASF), 36.0 parts of ion-exchanged water, and 0.5 parts of antifoaming agent BYK-011 using a mixer such as a Disper. The number of parts of each component listed above is the number of parts in the pigment paste.

[0111] First paint composition 182 parts of the acrylic resin emulsion of Production Example 1, 2.2 parts of dimethylaminoethanol, 40 parts of Cymel 327 (mixed alkylated melamine resin, manufactured by Allnex, solids content 90%), 69.0 parts of the pigment dispersion paste, 5 parts of the phosphate group-containing organic compound of Production Example 2, 0.4 parts of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts of Noigen EA-207D (amphiphilic compound, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., number average molecular weight 4200, solids content 55%) (3 parts in terms of solids), and 3 parts of linoleic acid (manufactured by Kishida Chemical Co., Ltd.) were uniformly dispersed, and dimethylaminoethanol was added to adjust the pH to 8.1. The mixture was diluted with deionized water to prepare an aqueous coating composition with a resin solids concentration of 32.0% by mass.

[0112] Preparation of the second coating composition Pigment dispersion paste A pigment dispersion paste was obtained by mixing and dispersing 3 parts of black pigment R5000 (Laven 5000), 18.6 parts of pigment dispersant Dispex (registered trademark) Ultra PA 4550 (manufactured by BASF), 36.0 parts of ion-exchanged water, and 0.5 parts of antifoaming agent BYK-011 using a stirrer such as a Disper.

[0113] Second paint composition 182 parts of the acrylic resin emulsion of Production Example 1, 2.2 parts of dimethylaminoethanol, 40 parts of Cymel 327 (mixed alkylated melamine resin, manufactured by Allnex, solid content 90%), 69.0 parts of the pigment dispersion paste prepared by the above procedure, and Black Diamond (registered trademark) M010 (manufactured by Ako Kasei Co., Ltd., average particle size 10 μm, active ingredient 100%) was used relative to 100 mass of resin solids. 20 parts, 5 parts of the phosphate group-containing organic compound of Production Example 2, 0.4 parts of lauryl acid phosphate, 50 parts of butyl cellosolve, 5.5 parts (3 parts in terms of solids) of Noigen EA-207D (amphiphilic compound, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., number average molecular weight 4200, solids content 55%), and 3 parts of linoleic acid (manufactured by Kishida Chemical Co., Ltd.) were uniformly dispersed, and dimethylaminoethanol was added to adjust the pH to 8.1. The mixture was diluted with deionized water to prepare an aqueous coating composition with a resin solids concentration of 15.8 mass%.

[0114] Multi-layer coating formation A zinc phosphate-treated dull steel plate, 0.8 mm thick, 30 cm long, and 40 cm wide, was electrodeposited with the cationic electrodeposition coating composition "Power Top U-50" (manufactured by Nippon Paint Automotive Coatings) to a dry film thickness of 20 μm and baked at 160°C for 30 minutes. A medium gray intermediate coating composition "OP-30P Middle Gray" (manufactured by Nippon Paint Automotive Coatings, polyester-melamine based paint, pre-diluted to 25 seconds (measured at 20°C using a No. 4 Ford cup)) was then sprayed onto the coated plate using an Anest Iwata W-101-132G air spray gun to a dry film thickness of 35 μm. The plate was then baked and cured at 140°C for 30 minutes to form a cured intermediate coating film with a brightness of 60 (45° acceptance angle). Next, the first coating composition was applied by air spraying at a room temperature of 23° C. and a humidity of 68% so as to give a dry film thickness of 11 μm. After setting for 4 minutes, the coating was preheated at 80° C. for 5 minutes. After preheating, the second coating composition was sprayed wet-on-wet using an air spray to a dry film thickness of 4 μm at a room temperature of 23° C. and a humidity of 68%. After setting for 4 minutes, the coating was preheated at 80° C. for 5 minutes. After preheating after application of the second coating composition, the coated plate was allowed to cool to room temperature, and then Macflow-O-1810 (a solvent-based clear coating manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was spray-painted onto the plate to a dry film thickness of 35 μm and allowed to set for 7 minutes. The coated plate was then baked in a dryer at 140°C for 30 minutes to obtain a coated test plate with a multi-layer coating film.

[0115] Other Examples and Comparative Examples Multilayer coating films were prepared in the same manner as in Example 1, except that the compositions of the first and second coating compositions, the brightness of the intermediate coating film, and the film thickness of the multilayer coating film were as shown in the tables below. In each table, the formulation of each coating composition other than the pigment component is the same as in Example 1, so it is omitted. The content of the pigment component in each table indicates the PWC (Pigment Weight Concentration) in the paint.

[0116] The details of the abbreviations given in the table below are shown below. Pigment A-1: ​​Black Diamond M010-1, manufactured by Ako Kasei, base material: natural mica, coating material: titanium and titanium oxide sintered material, average particle size: 10 μm Pigment A-2: Black Diamond M010-2, manufactured by Ako Kasei, base material: natural mica, coating material: titanium and titanium oxide sintered material, average particle size: 10 μm Pigment A-3: Ronastar Diamond Black IQ, manufactured by Merck, base material: Al2O3, coating material: TiO2 / SiO2 / Fe2O3, average particle size: 10 μm Pigment A-4: NK Black, manufactured by Nihon Koken Kogyo Co., Ltd., base material: Al2O3, coating material: black iron oxide (iron tetroxide: Fe3O4), average particle size: 11 μm Pigment A-5: Talc Black, manufactured by Nihon Koken Kogyo Co., Ltd. Base material: talc, Coating material: black iron oxide (iron tetroxide: Fe3O4), Average particle size: 8 μm Pigment A-6: FD-5090, manufactured by Asahi Kasei, base material: aluminum, coating material: - (none), average particle size: 9 μm Pigment A-7: ST1018RSJ3, manufactured by Nippon Sheet Glass Co., Ltd., base material: glass flake, coating material: TiO2, average particle size: 18 μm Pigment A-8: Xirallic NXT M260-60 Panthera Silver, manufactured by Merck. Base material: alumina flakes. Coating material: metal oxide (black) containing iron titanate (FeTiO3). Average particle size: 20 μm. Pigment A-9: Iriodin 602 WNT, manufactured by Merck. Base material: mica. Coating material: metal oxide (black) containing iron titanate (FeTiO3). Average particle size: 19 μm. Pigment A-10: SB-10, manufactured by Asahi Kasei, base material: ground aluminum pigment, coating material: none, average particle size: 10 μm Pigment A-11: 93-0647, manufactured by Toyo Aluminum, base material: aluminum, coating material: - (none), average particle size: 20 μm Pigment A-12: IRIODIN NEW TG BLUE WNT / IRIODIN 612 RUTILE WNT, manufactured by Merck. Base material: mica. Coating material: metal oxides including iron titanate (FeTiO3). Average particle size: 7 μm. Pigment A-13: Iriodin 121 / 221 / 111 / 219, manufactured by Merck. Base material: mica. Coating material: titanium oxide. Average particle size: 10 μm / 10 μm / 7 μm / 20 μm, respectively. Pigment A-14: Luxan CFX B502, manufactured by Eckart, base material: glass flake, coating material: TiO2, average particle size: 25 μm Pigment A-15: A-903S / A-781D, manufactured by CQV, base material: artificial mica, coating material: TiO2, average particle size: 20 μm Pigment A-16: A-781K-SP / A-761-SP, manufactured by CQV, base material: artificial mica, coating material: TiO2, average particle size: 18 μm / 20 μm, respectively Pigment A-17: UC-6700 / 4640NS / CP-315, manufactured by Nippon Boshoku Kogyo, Toyo Aluminum, and Asahi Kasei, respectively. Base material: aluminum flake. Coating material: none. Average particle size: 16 μm / 12 μm / 15 μm, respectively.

[0117] Pigment B-1: R5000, manufactured by Birla, carbon black Pigment B-2: E-2020, manufactured by Cabot, carbon black Pigment B-3: EH8082, Sun Chemical, Perylene Black Pigment B-4: FW200, Orion, carbon black

[0118] Pigment C-1:400RG, Tosoh, Quinacridone Red Pigment C-2: G-314, Sanyo Pigment, Cyanine Blue Pigment C-3: BLUE 6480, manufactured by Sun Chemical, Threon Blue Pigment C-4: 5206H / FVP336, Dainichi Seika Chemicals / Clariant, Cyanine Blue / Dioxane Violet Pigment C-5: CR-97, manufactured by Ishihara Sangyo Kaisha, titanium

[0119] The multi-layer coating films formed in the above Examples and Comparative Examples were evaluated as follows. The evaluation results are shown in the following table.

[0120] Brightness strength of multi-layer coating film Si 15 Measurement of Using a painted test panel having a multi-layer coating film formed in each example and comparative example, the brightness intensity Si 15 was measured using a BYK-maci (multi-angle (6-angle) colorimeter, brightness and particle sensitivity measuring instrument) manufactured by BYK.

[0121] Multi-layer coating saturation C * 15 Measurement of Using a painted test panel having a multi-layer coating film formed in each example and comparative example, the chroma C * 15The values ​​were measured using a BYK-maci (multi-angle (6-angle) colorimeter, brightness and particle intensity measuring instrument) manufactured by BYK.

[0122] Lightness of multi-layer coating film L * 15 and lightness L * 110 Measurement of Using a painted test panel having a multi-layer coating film formed in each example and comparative example, the lightness L * 15 and lightness L * 110 was measured using a BYK-maci (multi-angle (6-angle) colorimeter, brightness and particle sensitivity measuring instrument) manufactured by BYK.

[0123] Appearance evaluation of multi-layer coatings The coated test panels having the multi-layer coating film formed in each of the Examples and Comparative Examples were visually observed and evaluated according to the following criteria, with A and B being considered acceptable.

[0124] Evaluation criteria A: It can be recognized as black, but also has a soft feel and a moderate sense of shadow. B: There is a slight sense of color and brightness, but it is recognized as being within the black range. At the same time, there is a sense of softness and a moderate sense of shadow. C: The brightness and luminosity in the highlights are high, so it is outside the black category and is not a coating that is "black but also has softness and a sense of shadow." D: Only black is visible, and the sense of shadow and softness cannot be recognized. E: Although it is dark, the color is still recognizable, so it falls outside the black category. F: High brightness and lightness in the highlights, and although the color is dark, it is recognizable and falls outside the black range. G: The brightness and luminosity in the highlights are high and fall outside the black range, and the sense of shadow and softness cannot be recognized.

[0125] [Table 1]

[0126] [Table 2]

[0127] [Table 3]

[0128] It was confirmed that all of the multi-layer coating films of the Examples were coating films that could be recognized as black, yet had a suitable sense of shading.

[0129] The multi-layer coating films of Comparative Examples 1 and 2 have a chroma of C * 15 This is an example where the value exceeds 6. In this example, the coating film is not in the black category due to a lack of denseness and high saturation.

[0130] The multi-layer coating films of Comparative Examples 3 to 8 have a brightness of L * 110 exceeds 3, and L * 15 / L * 110 This is an example where the value is 9 or less. In this example, the coating film does not have a proper sense of shading, and is outside the black color category.

[0131] The multi-layer coating films of Comparative Examples 9 to 11 are L * 15 / L * 110 In this example, L is outside the range of 9 to 24. * 15 / L * 110 If it is too low, there will be no appropriate shadow effect. * 15 / L * 110 If the value is too high, the luminance and brightness in the highlights will be too high, and the coating will fall outside the black range.

[0132] The multi-layer coating films of Comparative Examples 23 and 24 have a brightness intensity of Si15 is outside the range of 2 to 10. In this example, Si 15 If the value is too low, only black is visible, and the sense of shadow and softness cannot be recognized. 15 If the value is too high, the luminance and brightness in the highlights will be too high, and the coating will fall outside the black range. [Industrial Applicability]

[0133] The multilayer coating film of the present disclosure is a coating film that can be recognized as black, yet has a moderate sense of shading and is excellent in design. Coated articles having the above multilayer coating film can be suitably used as various articles (for example, automobile bodies and parts thereof such as passenger cars, trucks, motorcycles, and buses).

Claims

1. A multi-layer coating film having a first coating film, a second coating film, and a clear coating film in this order, the first coating film contains a black pigment; the second coating film contains a brilliant black scale-like pigment and a black pigment, The incident light incident on the surface of the multi-layer coating film at an angle of 45 degrees is reflected at an angle of 15 degrees relative to the specular reflection light. ＊ C ＊ Chroma C in the h color system ＊ １５ is 6 or less, The incident light incident on the surface of the multi-layer coating film at an angle of 45 degrees is reflected at an angle of 110 degrees relative to the specular reflection light. ＊ C ＊ Lightness L in the h color system ＊ １１０ is less than or equal to 3, The incident light incident on the surface of the multi-layer coating film at an angle of 45 degrees is reflected at an angle of 15 degrees relative to the specular reflection light. ＊ C ＊ Lightness L in the h color system ＊ １５ and the lightness L ＊ １１０ The ratio L ＊ １５ / L ＊ １１０ is between 9 and 24, A light receiving unit is arranged in a direction perpendicular to the surface of the multilayer coating film, and light is irradiated onto the surface of the multilayer coating film at an angle of 15 degrees relative to the perpendicular direction, and the brilliance intensity Si measured by the light receiving unit is １５ is between 2 and 10, Multi-layer coating.

2. The bright black scale-like pigment contained in the second coating film is a scale-like pigment having a titanium sintered layer. The multi-layer coating film according to claim 1.

3. the lustrous black scaly pigment contained in the second coating film is a scaly pigment having a sintered titanium layer on a mica flat plate substrate; The multi-layer coating film according to claim 1.

4. the content of the glittering black scale pigment contained in the second coating film is 10% by mass or more and 30% by mass or less in terms of PWC, The content of the black pigment contained in the second coating film is 2% by mass or more and 12% by mass or less in terms of PWC. The multilayer coating film according to claim 1 or 2.

5. The content of the black pigment contained in the first coating film is 1.5% by mass or more and 5% by mass or less in terms of PWC. The multilayer coating film according to claim 1 or 2.

6. the average particle diameter of the glittering black scaly pigment contained in the second coating film is 5 to 14 μm; The multilayer coating film according to claim 1 or 2.

7. The object to be coated, A coated article comprising the multi-layer coating film according to claim 1 or 2 provided on the substrate.

8. The method comprises sequentially applying a first coating composition, a second coating composition and a clear coating composition to an object to be coated to form a multi-layer coating film; the first coating composition includes a black pigment; the second coating composition contains a brilliant black scale-like pigment and a black pigment, The incident light incident on the surface of the multi-layer coating film at an angle of 45 degrees is reflected at an angle of 15 degrees relative to the specular reflection light. ＊ C ＊ Chroma C in the h color system ＊ １５ is 6 or less, The incident light incident on the surface of the multi-layer coating film at an angle of 45 degrees is reflected at an angle of 110 degrees relative to the specular reflection light. ＊ C ＊ Lightness L in the h color system ＊ １１０ is less than or equal to 3, The incident light incident on the surface of the multi-layer coating film at an angle of 45 degrees is reflected at an angle of 15 degrees relative to the specular reflection light. ＊ C ＊ Lightness L in the h color system ＊ １５ and the lightness L ＊ １１０ The ratio L ＊ １５ / L ＊ １１０ is between 9 and 24, A light receiving unit is arranged in a direction perpendicular to the surface of the multilayer coating film, and light is irradiated onto the surface of the multilayer coating film at an angle of 15 degrees relative to the perpendicular direction, and the brilliance intensity Si measured by the light receiving unit is １５ is between 2 and 10, A method for manufacturing a coated article.

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