Painted bodies and paint compositions

Abstract

To provide a coated body that satisfies an excellent metallic tone or silky tone, and excoriation resistance simultaneously, and to provide a coating composition for forming the coated body.SOLUTION: A coated body has at least one layer of coating film on a base material. The coated body is such that: the coating film contains at least a binder resin and a glass pigment; a pencil hardness of a coating film surface is 5H or more; and a surface roughness Ra is 3.0 μm or less. (The pencil hardness is a pencil hardness measured in accordance with JIS K 5600-5-4:1999 (ISO / DIS 15184:1996.)SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a coated body having a metallic coating film formed on the surface of a base material such as plastic, and a coating composition for producing the coating film.

Background Art

[0002] For coating the casings of electronic devices such as notebook computers and mobile phones, it is necessary to form a coating film having high scratch resistance for protecting the devices. Further, in recent years, since a metallic appearance with a high-class feeling and a smooth (silky) touch are preferred, a coating film having both scratch resistance and high design quality is required.

[0003] In order to improve scratch resistance, it is known to make the coating film contain a glassy filler having shape anisotropy to make it highly hard (Patent Document 1). Further, in order to improve the metallic tone, a coating film composed of an acrylic resin, a pearlescent pigment, a polyester resin, and a curing agent is known (Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in order to obtain an excellent metallic tone and a silky tone, it is required to appropriately orient the pearlescent pigment and further suppress the unevenness of the pigment. Therefore, a coated body that simultaneously satisfies an excellent metallic tone, a silky tone, and scratch resistance has not been obtained.

[0006] The object of the present invention is to provide a coated body that simultaneously satisfies excellent metallic or silky texture and scratch resistance, and a paint composition for forming such a coated body. [Means for solving the problem]

[0007] The objective of the present invention was achieved as follows. 1. A coated body having at least one coating film on a substrate, The coating film comprises at least a binder resin and a glass pigment, the pencil hardness of the surface of the coating film is 5H or higher, and the surface roughness Ra is 3.0 μm or less. Pencil hardness is measured according to JIS K 5600-5-4:1999 (ISO / DIS 15184:1996). 2. The coated body according to claim 1, comprising a luminous pigment different from the glass pigment. 3. The coated body according to claim 1 or 2, wherein the coating film contains 1 to 30% by mass of the glass pigment. 4. The coated body according to any one of 1 to 3, wherein the glass pigment is in the form of a rod with a diameter of 5 to 20 μm and an average major axis of 10 to 100 μm. 5. The coated body according to any one of 1 to 4, wherein the binder resin comprises an acrylic resin (A) having at least crosslinkable functional groups and a resin (B) that can be crosslinked with the acrylic resin (A), and the content of resin (B) is 10 to 100 parts by mass per 100 parts by mass of resin (A). 6. The coated body according to 5, wherein the resin (B) is melamine resin. 7. The coated body according to any one of 1 to 6 above, wherein the binder resin is epoxy resin (C). 8. A paint composition for forming a coated body according to any of items 1 to 7 above. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a coated body that simultaneously satisfies excellent metallic or silky texture and scratch resistance, as well as a paint composition for forming such a coated body. [Modes for carrying out the invention]

[0009] The coated bodies and paint compositions of the present invention will be described in detail below, but are not limited thereto.

[0010] <Painted body> The coated body of the present invention can be manufactured by forming a coating film on a substrate by applying the coating composition of the present invention.

[0011] <Pencil hardness> The pencil hardness of the coated body of the present invention is measured according to JIS K 5600-5-4:1999 (ISO / DIS 15184:1996). This pencil hardness is defined in the following order from lowest to highest hardness: 6B, 5B, 4B, 3B, 2B, B, HB, F, H, 2H, 3H, 4H, 5H, and 6H. A coating with a grade of 6B has the lowest pencil hardness, while a coating with a grade of 6H has the highest pencil hardness. In the present invention, the pencil hardness is 5H or higher, preferably 6H or higher. Unless otherwise specified, the measurement atmosphere for the properties of the present invention is 23°C and 50% RH.

[0012] <Surface roughness Ra> The arithmetic mean surface roughness Ra of the coated body of the present invention is 3.0 μm or less, and preferably between 1.0 μm and 2.5 μm. If Ra exceeds 3.0 μm, the surface will have a rough texture and a silky feel cannot be obtained. The surface roughness Ra preferred for a silky feel and scratch resistance varies depending on the substrate and can be adjusted as appropriate. Ra can be measured in accordance with JIS B0601 (2013).

[0013] <coating film> The coating film of the present invention contains at least a binder resin and a glass pigment. In the present invention, the film thickness of the coating film depends on the amount of paint applied, and the amount of paint applied can be changed according to the type of substrate and application, but is usually 20 to 400 g / m². 2 It is 40-200g / m 2It is preferably so. The film thickness of the coating film is 3 to 80 μm, and preferably 10 to 50 μm.

[0014] The coating film of the present invention may be a plurality of layers, and it is possible to form a coating film of the present invention with a thickness of 3 to 80 μm on the surface of the coating film of the present invention in a polished or unpolished state.

[0015] ≪Binder resin≫ The binder resin of the present invention is not particularly limited as long as it is a binder resin used in paints, but preferably contains an acrylic resin (A), and more preferably contains a resin (B) that can crosslink with the acrylic resin (A). As the resin (B) that can crosslink, a melamine resin is preferable. Further, when applying a plurality of layers of the coating film of the present invention, it is preferably further contained an epoxy resin (C) from the viewpoint of particularly improving the adhesion.

[0016] [Acrylic resin (A)] The acrylic resin (A) of the present invention preferably contains an acrylic resin having a glass transition temperature of 50 to 1̀50 °C, a hydroxyl value of 10 to 150 mgKOH / g, and a number average molecular weight of 1,000 to 150,000, and can be used alone or in combination of one or more kinds.

[0017] The above acrylic resin is obtained by polymerizing a monomer such as α,β-unsaturated or its ester. Examples of the α,β-unsaturated acid or its ester include acrylic acid, methacrylic acid, and their methyl esters, ethyl esters, butyl esters, stearyl esters, 2-ethylhexyl esters, 2-hydroxyethyl esters, 3-hydroxypropyl esters, and the like.

[0018] In addition, examples of the comonomer that can be copolymerized with the above α,β-unsaturated acid or its ester include maleic acid, itaconic acid, fumaric acid, styrene, α-methylstyrene, vinyl acetate, vinyl propionate, and the like. When the above acrylic acid or acrylic acid ester polymer is a copolymer, the proportion of acrylic acid, methacrylic acid or its ester in the total copolymer is usually 10 to 75 mol%, preferably 25 to 60 mol%.

[0019] The above acrylic resin has a glass transition temperature of 50°C or higher and 150°C or lower, preferably 70°C or higher and 120°C or lower. When the glass transition temperature is 50°C or higher, the pencil hardness can be further improved, and when the glass transition temperature is 150°C or lower, the frequency of crack generation in the coating film can also be reduced, which is preferable.

[0020] In addition, the hydroxyl value of this acrylic resin is 10 mgKOH / g or higher and 150 mgKOH / g or lower, preferably 30 mgKOH / g or higher and 100 mgKOH / g or lower. Furthermore, the number average molecular weight of this acrylic resin, as measured by SEC in terms of standard polystyrene, is 1,000 or higher and 150,000 or lower, preferably 5,000 or higher and 100,000 or lower.

[0021] In the present invention, the glass transition temperature (Tg) refers to the value calculated using the following FOX formula.

[0022] 1 / Tg = W1 / Tg1 + W2 / Tg2 + ··· + Wi / Tgi + ··· + Wn / Tgn In the above FOX formula, Tg is the glass transition temperature (K) of the polymer composed of n types of monomers, Tg(1, 2, i, n) is the glass transition temperature (K) of the homopolymer of each monomer, W(1, 2, i, n) is the mass fraction of each monomer, and W1 + W2 + ··· + Wi + ··· + Wn = 1.

[0023] [Crosslinkable resin (B)] The resin (B) that can be crosslinked with the acrylic resin (A) of the present invention is not particularly limited as long as it reacts with the functional groups in the acrylic resin (A) to form crosslinks. Typical examples include amino resins such as melamine resin, benzoguanamine resin, urea resin, and thiourea resin, as well as polyisocyanate compounds, blocked isocyanate compounds, and polycarboxylic acid anhydrides such as trimellitic anhydride. Among these, melamine resin is preferably used.

[0024] Alkylated melamine resins are preferred as the melamine resin, and examples include methylated melamine resins, butylated melamine resins, and hexamethoxymethylated melamine resins. In the present invention, commercially available products such as the Nikarac series (manufactured by Nippon Carbide Industries, Ltd.), Cymel series (manufactured by Nippon Cytec Co., Ltd.), Melan series (manufactured by Showa Denko Materials Co., Ltd.), Uban series (manufactured by Mitsui Chemicals, Inc.), and Amidia series (manufactured by DIC Corporation) can be used.

[0025] In the present invention, when melamine resin is used, an acidic catalyst, such as p-toluenesulfonic acid, dodecylbenzenesulfonic acid, or weak base salts thereof, can be used.

[0026] [Epoxy resin (C)] The epoxy resin (C) of the present invention is useful in that it improves adhesion without repelling of the coating film when applying multiple coats of the coating film of the present invention.

[0027] Examples of epoxy resins (C) of the present invention include bisphenol-type epoxy resins such as bisphenol A-type epoxy resin and bisphenol F-type epoxy resin, naphthalene-type epoxy resin, biphenyl-type epoxy resin, novolac-type epoxy resin, cyclic aliphatic epoxy resin, glycidylamine-type resin, heterocyclic epoxy resin, and polyfunctional epoxy resin. One or more of these can be used in combination.

[0028] Specifically, preferred examples include solid epoxy resins synthesized from bisphenol A and epihalohydrins, such as epichlorohydrin, and solid epoxy resins obtained by the extension reaction of bisphenol A with epoxy resins derived from bisphenol A, divalent phenols, and epihalohydrins.

[0029] Such epoxy resins that are available include jER1001, jER1004, jER1004F, jER1007, jER4005P (manufactured by Mitsubishi Chemical Corporation), EPICLON1050, EPICLON3050, EPICLON4050 (manufactured by DIC Corporation), Epotote YD014D (manufactured by Nippon Steel & Sumitomo Metal Chemical Corporation), and EPONANYANPES-904 (manufactured by Nanya Plastics Co., Ltd.).

[0030] The softening point of the epoxy resin (C) is not particularly limited, but is preferably 60 to 150°C, and the epoxy equivalent is also not particularly limited, but is preferably 400 to 3000.

[0031] The melamine resin of the present invention is preferably contained in an amount of 40 to 100 parts by mass, and more preferably 50 to 80 parts by mass, per 100 parts by mass of acrylic resin. The epoxy resin is preferably contained in an amount of 0.1 to 20 parts by mass, and more preferably 1.0 to 10 parts by mass, per 100 parts by mass of acrylic resin. The total amount of melamine resin and epoxy resin is preferably 10 to 100 parts by mass, and more preferably 50 to 90 parts by mass, per 100 parts by mass of acrylic resin.

[0032] The binder resin of the present invention constitutes 40 to 95% by mass of the entire coating film, and preferably 60 to 90% by mass.

[0033] ≪Glass Pigments≫ The glass pigment of the present invention can be used without particular limitations, but it is preferably cylindrical or rod-shaped with a diameter of 5 to 20 μm and a major axis of 10 to 100 μm, and more preferably with a diameter of 8 to 17 μm. It is preferably milled fiber obtained by crushing glass long fibers, and milled fiber (manufactured by Asahi Fiberglass Co., Ltd.), milled fiber (manufactured by Owens Corning Co., Ltd.), milled fiber (manufactured by Central Fiberglass Co., Ltd.), etc. can be obtained commercially.

[0034] The glass pigment of the present invention is present in an amount of 1 to 30% by mass of the entire coating film, and preferably 5 to 20% by mass.

[0035] ≪Luminous Pigments≫ Examples of the luminous pigments of the present invention include metal pigments such as nickel, gold, silver, aluminum, bronze, copper, and stainless steel, mica pigments, graphite pigments, glass flake pigments, metal-coated glass powder, metal-coated mica powder, metal-coated plastic powder, and flaky iron oxide pigments. Aluminum pigments are particularly preferred.

[0036] [Aluminum pigment] The aluminum pigment of the present invention is preferably in the form of cornflakes or silver dollars. Both the cornflake type and the silver dollar type of aluminum pigment are flaky, but the cornflake type has jagged edges, while the silver dollar type has smoothed edges around the aluminum flakes.

[0037] In this invention, it is particularly preferable to use a silver dollar-type aluminum pigment. By using it simultaneously with a glass pigment, scratch resistance can be improved.

[0038] The silver dollar-type aluminum pigment preferably has an average particle size of 3 to 60 μm and an aspect ratio of 4 to 100. The aluminum flakes preferably have an average particle size of 3 to 60 μm and an aspect ratio of 4 to 100. The average thickness is not particularly limited, but is preferably 0.005 μm or more, and particularly preferably 0.02 μm to 3 μm.

[0039] The aluminum pigment is preferably a resin-coated aluminum flake, in which the surface is coated with a resin.

[0040] The average particle diameter is determined by calculating the volume average from the particle size distribution measured by the laser diffraction method. The average thickness can be calculated from the flake's hiding power and density. The average aspect ratio is expressed as average thickness / average particle diameter.

[0041] Examples of resins used for coating include known resins such as acrylic resins polymerized with acrylic acid esters or methacrylic acid esters as the main components, polyester resins, and polyurethane resins, but acrylic resins are preferred.

[0042] The coating amount is preferably 0.1 to 25 g of resin per 100 g of aluminum pigment, and particularly preferably 5 to 20 g.

[0043] As the aluminum pigment of the present invention, commercially available resin-coated aluminum pastes such as the FZ, FZC, FZH series, BP, BPA, BPZ series, high-gloss aluminum pastes 46, 54, 56, 63, 76 series (manufactured by Toyo Aluminum Co., Ltd.), Asahi Kasei aluminum pastes FD, GX / BS series, M~MH series, PV-H, TR, LR, THR, HR, CR series, and CP-R series (manufactured by Asahi Kasei Chemicals Corporation) can be used.

[0044] The aluminum pigments of the present invention can be used in combination of one or more types, in which case it is preferable to combine the cornflake type and the silver dollar type. In this case, it is preferable that the ratio of silver dollar type to cornflake type is 99 / 1 to 60 / 40 (by mass).

[0045] The luminous pigment of the present invention is preferably contained in the coating film at an amount of 1 to 30% by mass, and more preferably at an amount of 3 to 20% by mass.

[0046] <<Other Pigments>> The coating film of the present invention may contain a coloring pigment and an extender pigment. Known materials can be used as the coloring pigment, such as inorganic pigments like titanium dioxide and carbon black, and organic pigments like phthalocyanine pigments and azo pigments. Similarly, known materials can be used as the extender pigment, such as talc, mica, barium sulfate, clay, and calcium carbonate.

[0047] <<Other additives>> The coating film of the present invention may contain antibacterial agents, antiviral agents, insecticides, light stabilizers, ultraviolet absorbers, antistatic agents, resin beads, and conductivity imparters as appropriate, depending on the purpose.

[0048] [Antibacterial agents, antiviral agents] The coating film of the present invention may contain an antibacterial agent or an antiviral agent, or it may contain both an antibacterial agent and an antiviral agent. Furthermore, some antibacterial agents can impart antiviral function, and some antiviral agents can impart antibacterial function. Such agents that can impart both antibacterial and antiviral function can also be called antibacterial / antiviral agents.

[0049] Examples of antibacterial and antiviral agents include microparticles on which metal ions are supported on inorganic materials (porous materials such as zeolites, photocatalytic particles such as titanium dioxide, phosphate minerals such as apatite, metal phosphates, etc.), composite particles of metal / inorganic oxides, organic or inorganic acids, metal iodides, metal salts (e.g., salts of silver, copper, zinc, tungsten, or molybdenum), silver particles, copper particles, cuprous oxide particles, quaternary ammonium salts, pyrithione compounds, sulfonic acid group-containing polymers, amino group-containing polyvinyl alcohol, organic nitrogen bromine compounds, and H-type carboxyl group-containing polymers. Materials containing copper elements and H-type carboxyl group-containing polymers are particularly preferred.

[0050] The antibacterial or antiviral agent content in the coating film of the present invention is preferably 0.1 to 5% by mass. The antibacterial or antiviral agent may be used alone or in combination of two or more.

[0051] [Resin beads] The resin beads of the present invention are spherical organic fine particles obtained by polymerizing monomers such as methacrylic acid esters, styrene, silicone, nylon, polyethylene, polymethyl methacrylate, and polyacrylonitrile. Polymerization methods include suspension polymerization, emulsion polymerization, solution polymerization, and precipitation polymerization. Commercially available resin beads manufactured by the above methods can be used.

[0052] The resin beads in the coating film are preferably contained in an amount of 0 to 20% by mass, and more preferably in an amount of 0 to 5% by mass. Furthermore, the average particle size of the resin beads is preferably 30 to 150 μm. As the resin bead content increases, the hardness of the coating film surface decreases, and the surface roughness of the coating film increases.

[0053] <Base material> In the coated body of the present invention, the substrate is not particularly limited, and various shapes of substrates can be selected depending on the application of the coated body. It is not limited to metal substrates, ceramic substrates, plastic substrates, etc.

[0054] Examples of metal substrates include aluminum, magnesium, titanium, and stainless steel. Examples of plastic substrates include olefin polymers such as PPE (polyphenylene ether) resins, polystyrene resins, polypropylene, and polyethylene; polycarbonate resins; acrylic resins such as polymethyl methacrylate and ABS resins.

[0055] <Paint composition> The coating composition of the present invention contains the material that forms the aforementioned coating film, and further contains the aforementioned acidic catalyst, solvent, and other additives necessary for the coating composition for curing the coating film. The solid content is 0.1 to 95% by mass, preferably 1 to 20% by mass.

[0056] <Additives required for other coating compositions> The coating composition of the present invention may appropriately incorporate additives commonly used in coating compositions in the coating industry, such as surface modifiers, wetting agents, dispersants, emulsifiers, thickeners, anti-settling agents, anti-skinning agents, anti-sagging agents, defoaming agents, anti-color separation agents, leveling agents, drying agents, plasticizers, etc., depending on the purpose. Commercially available products can be suitably used as these additives.

[0057] Organic solvents Organic solvents that can be used in the paint composition of the present invention include those commonly used in paints, such as hydrocarbon solvents like toluene and xylene, ketones like methyl ethyl ketone and diisobutyl ketone, esters like ethyl acetate, butyl acetate and cellosolve acetate, and alcohols like 2-ethylhexanol.

[0058] <Method for manufacturing coating film> In the present invention, a coating film can be formed by applying a coating composition to a substrate and then drying it. The drying method for the formed coating film is not particularly limited and may be either natural drying at ambient temperature or forced drying using a drying machine or the like. For example, when melamine resin is used as the crosslinking resin (B) of the coating, a coating film can be obtained by drying the coating at a temperature of 120 to 190°C for 10 to 50 minutes after application.

[0059] The coating can be produced using conventional known coating methods, such as brush coating, roller coating, trowel coating, spatula coating, flow coater coating, and spray coating (e.g., air spray coating, airless spray coating, etc.).

[0060] Before applying the coating film of the present invention to a substrate, the substrate surface can be roughened or a primer layer can be provided.

[0061] There are no particular restrictions on the roughening of the substrate surface, but known surface treatment methods include polishing, sanding, sealing, blasting, and chemical conversion treatment of the substrate surface.

[0062] There are no particular restrictions on the primer layer, but known resin-based coatings such as epoxy resin, acrylic resin, urethane resin, alkyd resin, polyester resin, and silicone resin are examples, however, epoxy resin-based coatings are preferred from the viewpoint of adhesion to the substrate. Furthermore, the thickness of the primer layer is preferably 10 to 150 μm. [Examples]

[0063] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to the examples described below. Unless otherwise specified, measurements were taken at 23°C and under a 50% RH atmosphere.

[0064] <Paint composition> The paint was prepared by mixing the raw materials according to the formulations shown in Tables 1-3 and dispersing them using known methods. The materials used are as follows. Units in the table are parts by mass.

[0065] ≪Acrylic resin (A)≫ (A-1): Acrydic AU-7005, heating residue 55% by mass, hydroxyl value 70 mg KOH / g, Tg 90℃, manufactured by DIC Corporation. (A-2): Acrydic VU-191, heating residue 55% by mass, hydroxyl value 60 mg KOH / g, Tg 95℃, manufactured by DIC Corporation. (A-3): Acrydic A-811, heating residue 50% by mass, hydroxyl value 34 mg KOH / g, Tg 20℃, manufactured by DIC Corporation.

[0066] ≪Crosslinked resin (B)≫ (B-1): Cymel 325, imino-based methylated melamine resin varnish, heating residue 80% by mass, manufactured by Nippon Cytec Co., Ltd. (B-2): Nikalac MS-11, methylated melamine resin varnish, heating residue 60% by mass, manufactured by Nippon Carbide Industries Co., Ltd. (B-3): Yuban 20SE60 Butylated Melamine Resin Varnish, Heat Residue 60% by Mass, Manufactured by Mitsui Chemicals, Inc.

[0067] ≪Epoxy resin (C)≫ (C-1): Epiclon 1050-70, heating residue 70% by mass, manufactured by DIC Corporation. (C-2): jER1001X-70, heating residue 70% by mass, manufactured by Mitsubishi Chemical Corporation

[0068] ≪Glass Pigments≫ Milled fiber (1): EFH50-01, diameter 11 μm, major axis 50 μm, manufactured by Central Glass Fiber Co., Ltd. Milled fiber (2): EFK80-31, diameter 13 μm, major diameter 80 μm, manufactured by Central Glass Fiber Co., Ltd. Milled Fiber (3): EFH30-01, diameter 11 μm, major axis 30 μm, manufactured by Central Glass Fiber Co., Ltd. Milled Fiber (4): EFDE50-01, diameter 6 μm, major axis 50 μm, manufactured by Central Glass Fiber Co., Ltd. Milled Fiber (5): EFH150-31, diameter 11 μm, major axis 150 μm, manufactured by Central Glass Fiber Co., Ltd. Irregularly shaped glass: CF0023-05C, average particle size 12 μm, manufactured by Nippon Frit Co., Ltd. Spherical glass: EMB-20, average particle size 10 μm, manufactured by Potters Barotini Co., Ltd.

[0069] ≪Luminous Pigments≫ Silver dollar type aluminum pigment (1): FZC6340, heating residue 57% by mass, average particle size 12 μm, aspect ratio 40, manufactured by Toyo Aluminum Co., Ltd. Silver Dollar Type Aluminum Pigment (2): FZC5620, Heat Residue 55% by Mass, Average Particle Size 18 μm, Aspect Ratio 90, Manufactured by Toyo Aluminum Co., Ltd. Silver Dollar Type Aluminum Pigment (3): FZC6360, Heat Residue 52% by Mass, Average Particle Size 10 μm, Aspect Ratio 40, Manufactured by Toyo Aluminum Co., Ltd. Cornflake-type aluminum pigment (1): FX7160, heating residue 50% by mass, average particle size 17 μm, aspect ratio 60, manufactured by Toyo Aluminum Co., Ltd. Cornflake-type aluminum pigment (2): FX7130, heating residue 45% by mass, average particle size 21 μm, aspect ratio 70, manufactured by Toyo Aluminum Co., Ltd. Pearlescent pigment: Mearlin Exteior CFS Bright Silverr 1303Z, heat residue 100% by mass, average particle size 19 μm, aspect ratio 60, manufactured by BASF Ltd.

[0070] ≪Other≫ Resin beads 1: Techpolymer MBX-50, average particle size 50 μm, manufactured by Sekisui Chemical Co., Ltd. Acid catalyst 1: NACURE3525 (Dinonyl naphthalenedisulfonic acid), manufactured by KING INDUSTRIES. Silicone-based surface modifier 1: BYK-300, NV52 by mass, manufactured by BYK-Chemie Co., Ltd. Anti-settling agent 1: RHEOBYK-410, NV52 by mass, manufactured by BYK-Chemie Co., Ltd.

[0071] [Table 1]

[0072] [Table 2]

[0073] [Table 3]

[0074] Next, a two-component epoxy resin primer (Eponics #10, manufactured by Dainippon Paint Co., Ltd.) was applied by spray coating to an aluminum substrate A5052 (150 mm long, 70 mm wide, 2 mm thick) in an amount that resulted in a dry film thickness of 10 to 150 μm. After being left for 10 minutes, it was dried at 100°C for 30 minutes to form a primer layer. On this primer layer, the paints described in Examples 1 to 22 and Comparative Examples 1 to 9 in Tables 1 to 3 were applied in an amount that resulted in a dry film thickness of 25 to 35 μm. After being left for 10 minutes, it was dried at 150°C for 30 minutes to obtain the coated bodies of the Examples and Comparative Examples. These sample coated bodies were used as test specimens for the following tests, and the results obtained are shown in Tables 4 to 6.

[0075] <Pencil hardness> Using the aforementioned test specimens, the pencil hardness of the coating film before chemical treatment was determined using a scratch hardness test pencil (Uni MITSUBISHI, manufactured by Mitsubishi Pencil Co., Ltd.) in accordance with JIS K 5600-5-4:1999 (ISO / DIS 15184:1996). <Surface roughness Ra> The arithmetic mean roughness Ra can be measured under the following conditions. [Arithmetic mean roughness measurement conditions] Measuring instrument: Keyence Corporation's one-shot 3D surface shape measuring machine "VR-5000 / 5200" Measurement area: 25mm x 18mm Cut-off length: 0.8mm

[0076] <Adhesion> A straight cut was made on the surface of the coating of the test specimen using a utility knife at a cutting angle of 60°, and then another cut was made at a 60° angle to the first cut. After that, cellophane tape was firmly applied to cover the cut, and the cellophane tape was peeled off at a 45° angle to the surface of the coating. After the cellophane tape was removed, the degree of coating peeling was visually determined according to the following evaluation criteria. ○: No peeling at all. △: There is slight peeling at the cut area. ×: The paint film surface at the cut area peels off completely.

[0077] <Scratch resistance> A friction test was performed on the coated surface of the aforementioned test specimen by moving a 2kg load abrasive with cotton canvas attached back and forth 200 times, and the results were visually evaluated according to the following evaluation criteria. ○: No change on the surface of the coating. △: Scratches are visible on the surface of the coating, but the base material is not exposed. ×: Partial or complete exposure of the base material is observed.

[0078] <Metallic finish> Using the aforementioned test specimens, the FI values ​​were calculated using the 15°, 45°, and 110° values ​​measured with "BYK-macI" (product name, manufactured by BYK-gardner), and the metallic appearance was determined according to the following evaluation criteria. The FI value is a value indicating the flip-flop properties that give a metallic appearance, and is defined by the following formula. △Values ​​above this range are within the range of practical use.

[0079]

number

[0080] <Silky texture> The surface of the coating on the aforementioned test specimen was rubbed with a finger, and the silky texture was judged according to the following evaluation criteria. △ indicates a range that is practically usable. ○: The texture is smooth, and there is almost no feeling of snagging. △: The texture is smooth, but there are some areas that feel rough. ×: The texture is rough and not smooth.

[0081] [Table 4]

[0082] [Table 5]

[0083] [Table 6]

[0084] As can be seen from the results in Tables 4-6, the present invention makes it possible to obtain a metallic paint composition with excellent chemical resistance in a single-coat application and a coated body thereof.

Claims

1. A coated body having at least one coating film on a substrate, The coating film is formed from a paint composition containing at least a binder resin and a glass pigment, the pencil hardness of the surface of the coating film is 5H or higher, and the surface roughness Ra is 3.0 μm or less, and with respect to the paint composition, The binder resin comprises an acrylic resin (A) having at least crosslinkable functional groups and a glass transition temperature (Tg) of 50 to 150°C, The binder resin comprises the acrylic resin (A) and a crosslinkable resin (B), wherein the crosslinkable resin (B) is a melamine resin, and the content of the crosslinkable resin (B) is 10 to 100 parts by mass per 100 parts by mass of the acrylic resin (A), and the binder resin may also contain an epoxy resin (C), and the content of the epoxy resin (C) is 0 to 20 parts by mass per 100 parts by mass of the acrylic resin (A). The glass pigment is in the form of a rod with a diameter of 5 to 20 μm and an average major axis of 10 to 100 μm, The glass pigment is contained in a different luminous pigment, wherein the luminous pigment is a flaky aluminum pigment, and is either cornflake type or silver dollar type. A coated body wherein the coating film contains 1 to 30% by mass of the glass pigment and 1 to 30% by mass of the luminous pigment. (Pencil hardness is measured according to JIS K 5600-5-4:1999 (ISO / DIS 15184:1996).)

2. The coated body according to claim 1, wherein the aluminum pigment is a resin-coated aluminum flake in which 0.1 to 25 g of resin is coated per 100 g of aluminum pigment.

3. The acrylic resin (A) has a glass transition temperature of 50 to 150°C, a hydroxyl value of 10 to 150 mg KOH / g, and a number average molecular weight of 1,000 to 150,000. The coated body according to claim 1, wherein the crosslinkable resin (B) is any of melamine resin, benzoguanamine resin, urea resin, or thiourea resin that reacts with the functional groups in the acrylic resin (A) to form crosslinks.

4. The coated body according to claim 3, wherein the melamine resin is an alkylated melamine resin.

5. The coated body according to any one of claims 1 to 4, wherein the binder resin further comprises an epoxy resin (C), and the epoxy resin (C) is a bisphenol A type epoxy resin having a softening point of 60 to 150°C and an epoxy equivalent of 400 to 3000.

6. A paint composition comprising at least a binder resin and a glass pigment, The binder resin comprises an acrylic resin (A) having at least crosslinkable functional groups and a glass transition temperature (Tg) of 50 to 150°C, The binder resin comprises the acrylic resin (A) and a crosslinkable resin (B), wherein the crosslinkable resin (B) is a melamine resin, and the content of the crosslinkable resin (B) is 10 to 100 parts by mass per 100 parts by mass of the acrylic resin (A), and the binder resin may also contain an epoxy resin (C), and the content of the epoxy resin (C) is 0 to 20 parts by mass per 100 parts by mass of the acrylic resin (A). The glass pigment is in the form of a rod with a diameter of 5 to 20 μm and an average major axis of 10 to 100 μm, A paint composition comprising a luminous pigment different from the glass pigment, wherein the luminous pigment is a flaky aluminum pigment, either cornflake type or silver dollar type, and the paint composition contains 1 to 30% by mass of the glass pigment and 1 to 30% by mass of the luminous pigment with respect to the film-forming material contained in the paint composition.

7. The paint composition according to claim 6, wherein the aluminum pigment is a resin-coated aluminum flake in which 0.1 to 25 g of resin is coated per 100 g of aluminum pigment.

8. The acrylic resin (A) has a glass transition temperature of 50 to 150°C, a hydroxyl value of 10 to 150 mg KOH / g, and a number average molecular weight of 1,000 to 150,000. The paint composition according to claim 6, wherein the crosslinkable resin (B) is any of melamine resin, benzoguanamine resin, urea resin, or thiourea resin that reacts with the functional groups in the acrylic resin (A) to form crosslinks.

9. The paint composition according to claim 8, wherein the melamine resin is an alkylated melamine resin.

10. The paint composition according to any one of claims 6 to 9, wherein the binder resin further comprises an epoxy resin (C), the epoxy resin (C) being a bisphenol A type epoxy resin having a softening point of 60 to 150°C and an epoxy equivalent of 400 to 3000.

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