Primer, and coated article and method for producing the same

Abstract

To provide a primer that inhibits plasticizer bleeding from polyvinyl chloride coatings while ensuring an adequate pot life.SOLUTION: A primer comprises: an acrylic-silicone copolymer (I) that is a copolymer composed of a monomer (a) of formula (1) and a monomer (b) having a group of formula (2) and a polymerizable unsaturated group, wherein monomer (b) makes up 0.2-10.0 mass% per the total amount of monomers (a) and (b), and the Tg is 20°C or higher; and a silane compound (II) of formula (3), wherein the silane compound (II) constitutes 60-150 pts.mass per 100 pts.mass of the acrylic-silicone copolymer (I).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a primer, and to a coated article and a method for producing the same. [Background technology]

[0002] A widely used building material is a steel plate coated with a polyvinyl chloride resin film, commonly known as PVC steel plate. Since polyvinyl chloride resin is relatively hard and brittle when it is simply made by polymerizing vinyl chloride monomer, the polyvinyl chloride resin formed as a film on the steel plate for construction contains a large amount of plasticizer to give it flexibility.

[0003] Therefore, when a topcoat film is formed by painting on this polyvinyl chloride resin film, a bleeding phenomenon occurs in which the plasticizer migrates from the polyvinyl chloride resin film into the topcoat film over time, which can impair the performance of the topcoat film. For this reason, a base coat or primer is applied on the polyvinyl chloride film beforehand, and then a topcoat film is formed (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2021-134360 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when using the primer described in Patent Document 1, the reaction between the epoxy group of the base resin and the amino group of the curing agent is utilized, so there is a problem that the pot life at the painting site is short. The present invention provides a primer that effectively suppresses bleeding of plasticizer from a vinyl chloride resin film while providing a sufficient pot life, as well as a coated article using this primer and a method for producing the same. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention employs the following configuration. [1] A primer that is applied to a metal substrate having a polyvinyl chloride resin film formed on its surface before applying a topcoat paint, Contains an acrylic silicone copolymer (I) and a silane compound (II), The acrylic silicone copolymer (I) is a copolymer of a monomer (a) represented by the following formula (1) and a monomer (b) having a group represented by the following formula (2) and a polymerizable unsaturated group, the ratio of the monomer (b) to the total amount of the monomer (a) and the monomer (b) is 0.2 to 10.0 mass%, The glass transition temperature Tg of the acrylic silicone copolymer (I) is 20° C. or higher; The silane compound (II) is a compound represented by the following formula (3): A primer comprising 60 to 150 parts by mass of the silane compound (II) based on 100 parts by mass of the acrylic silicone copolymer (I).

[0007] [ka]

[0008] (In the above formula (1), R 1 represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a cycloalkyl group having 6 carbon atoms; R 2 represents a hydrogen atom or a methyl group.

[0009] [ka]

[0010] (In the formula (2), X 1 , X 2 and X 3 are each independently an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms. 1 , X 2 and X 3At least one of these is an alkoxy group having 1 to 8 carbon atoms.)

[0011] [ka]

[0012] (In the formula (3), X 5 , X 6 , X 7 and X 8 are each independently an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms. 5 , X 6 , X 7 and X 8 At least one of these is an alkoxy group having 1 to 8 carbon atoms.)

[0013] [2] The monomer (a) is R 1 is a hydrogen atom, and a monomer (a1) selected from (meth)acrylic acid, 1 and a monomer (a2) selected from a (meth)acrylic acid ester, in which R is an alkyl group having 1 to 12 carbon atoms, or a cycloalkyl group having 6 carbon atoms.

[0014] [3] A metal substrate, a polyvinyl chloride resin film formed on a surface of the metal substrate, a primer layer formed on the polyvinyl chloride resin film, and a topcoat film formed on the primer layer; A coated article, wherein the primer layer is a coating film obtained by applying the primer according to [1] or [2]. [4] The coated article according to [3], wherein the metal substrate is a steel material.

[0015] [5] A method for producing a coated article, comprising coating a metal substrate having a polyvinyl chloride resin film formed on its surface with the primer described in [1] or [2], and then coating the substrate with a topcoat paint. [6] The method for producing a coated article according to [5], wherein the metal substrate is a steel material. Effect of the Invention

[0016] The primer of the present invention can effectively suppress the bleeding of plasticizer from the polyvinyl chloride resin film, and also provides a sufficient pot life. Furthermore, according to the coated article and production method thereof of the present invention, it is possible to obtain a coated article in which bleeding of plasticizer from the vinyl chloride resin coating is suppressed, and since a sufficient pot life can be ensured, production is also easy. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] As used in the specification and claims, the following terms have the following definitions: "(Meth)acrylic acid" is a general term for methacrylic acid and acrylic acid. "(Meth)acrylic acid ester" is a general term for methacrylic acid ester and acrylic acid ester. The symbol "~" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits.

[0018] <Primer> The primer of the present embodiment is a primer that is applied to a metal substrate having a polyvinyl chloride resin film formed on the surface thereof before a topcoat paint is applied thereto, and contains an acrylic silicone copolymer (I) and a silane compound (II).

[0019] [Acrylic silicone copolymer (I)] The acrylic silicone copolymer (I) is a copolymer of a monomer (a) represented by the following formula (1) and a monomer (b) described below.

[0020] [ka]

[0021] In the formula (1), R 1 represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a cycloalkyl group having 6 carbon atoms; R 2 represents a hydrogen atom or a methyl group. The monomer (a) is R 1 is a hydrogen atom, and a monomer (a1) selected from (meth)acrylic acid, 1 It is preferable that the monomer (a2) contains both a monomer selected from a (meth)acrylic acid ester in which R is either an alkyl group having 1 to 12 carbon atoms or a cycloalkyl group having 6 carbon atoms.

[0022] The proportion of the monomer (a1) relative to the total amount of the monomer (a) is preferably 0.5 to 5.0 mass%, more preferably 0.5 to 3.0 mass%. When the proportion of the monomer (a1) is equal to or greater than the preferred lower limit, adhesion is improved, and when the proportion of the monomer (a1) is equal to or less than the preferred upper limit, stability of the coating material is ensured.

[0023] Monomer (a1) may include one or both of methacrylic acid, acrylic acid. The proportion of the monomer (a2) in the total amount of the monomer (a) is preferably from 95.0 to 99.5 mass %, and more preferably from 97.0 to 99.5 mass %.

[0024] The monomer (b) has a group represented by the following formula (2) (hereinafter sometimes referred to as "functional group (2)") and a polymerizable unsaturated group. The monomer (b) may have one or more functional groups (2). The monomer (b) may have one or more polymerizable unsaturated groups, but in consideration of solubility in a solvent, it preferably has one polymerizable unsaturated group. The monomer (b) preferably has a polymerizable unsaturated group at one end and a functional group (2) at the other end.

[0025] [ka]

[0026] In the formula (2), X 1 , X 2 and X 3are each independently an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms. 1 , X 2 and X 3 At least one of them is an alkoxy group having 1 to 8 carbon atoms.

[0027] X 1 , X 2 and X 3 When each of these is an alkyl group, the number of carbon atoms is preferably 1 to 3, and more preferably 1 or 2, in order not to inhibit the reactivity of the alkoxy group. X 1 , X 2 and X 3 The number of alkoxy groups is 1 or more, preferably 2 or 3, and more preferably 3, in order to strengthen the crosslinking after coating.

[0028] Examples of the polymerizable unsaturated group contained in the monomer (b) include an acryloyl group, a methacryloyl group, an acryloyloxy group, a methacryloyloxy group, a vinyl group, and an allyl group. Among these, the monomer (b) is preferably one having an acryloyloxy group or a methacryloyloxy group as a polymerizable unsaturated group, and more preferably one having a methacryloyloxy group, because of its favorable reactivity.

[0029] In order to copolymerize with the (meth)acrylic monomer (a), the monomer (b) is preferably a compound represented by the following formula (4) having an acryloyloxy group or methacryloyloxy group as a polymerizable unsaturated group at one end and a functional group (2) at the other end.

[0030] [ka]

[0031] In the formula (4), X 1 , X 2 and X 3is the same as that in the above formula (2), and the preferred embodiments are also the same. R 3 represents a hydrogen atom or a methyl group. Q represents an alkylene group having 1 to 3 carbon atoms. Q preferably has 1 or 2 carbon atoms.

[0032] Specific examples of the monomer (b) include trimethoxysilane derivatives such as 3-methacryloxypropyltrimethoxysilane, triethoxysilane derivatives such as 3-methacryloxypropyltriethoxysilane, dimethoxysilane derivatives, and diethoxysilane derivatives such as 3-methacryloxypropylmethyldiethoxysilane. The monomer (b) can be used alone or in combination of two or more kinds.

[0033] The acrylic silicone copolymer (I) of this embodiment is a copolymer in which the proportion of monomer (b) relative to the total amount of monomer (a) and monomer (b) is 0.2 to 10.0 mass %. The proportion of the monomer (b) is preferably 1 to 7% by mass.

[0034] By making the proportion of monomer (b) 0.2% by mass or more, bleeding of the plasticizer from the vinyl chloride resin film to the topcoat film can be effectively suppressed. By making the proportion of monomer (b) 10.0% by mass or less, the primer layer can be prevented from becoming hard and brittle, and good adhesion to the vinyl chloride resin film can be ensured.

[0035] The acrylic silicone copolymer (I) of this embodiment has a glass transition temperature Tg of at least 20° C. The glass transition temperature Tg of the acrylic silicone copolymer (I) is preferably 20 to 80° C., and more preferably 20 to 60° C. By having a glass transition temperature Tg of 20° C. or higher, bleeding, in which the plasticizer migrates from the vinyl chloride resin film to the topcoat film, can be effectively suppressed. By having a glass transition temperature Tg of not more than the preferred upper limit, the coating film has flexibility.

[0036] The acrylic silicone copolymer (I) of the present embodiment may be one in which other monomers are copolymerized in addition to the monomer (a) and the monomer (b) as long as the effects of the present invention are not impaired. Examples of the other monomers include vinyl acetate, styrene, and acrylamide. The other monomers can be used alone or in combination of two or more. The total amount of monomer (a) and monomer (b) is preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 100% by mass, of all monomers copolymerized to obtain the acrylic silicone copolymer (I).

[0037] The acrylic silicone copolymer (I) of this embodiment is preferably a random copolymer obtained by randomly polymerizing the monomer (a), the monomer (b), and other monomers that are added as necessary. The polymerization method for obtaining the acrylic silicone copolymer (I) of this embodiment is not particularly limited, but a radical solution polymerization method in which copolymerization is carried out in a solvent in the presence of a polymerization initiator is preferred.

[0038] The solvent may be any solvent that dissolves the polymerization initiator and each monomer, and examples of the solvent include water, organic solvents, and fluorine-based solvents. From the viewpoint of solubility, organic solvents are preferred. Examples of the organic solvent include cyclohexanone, methyl isobutyl ketone, ethyl acetate, butyl acetate, isobutyl acetate, methylcyclohexane, and propylene glycol monomethyl ether acetate. The solvent may be used alone or in combination of two or more. The polymerization initiator includes peroxides, azo compounds, and the like.

[0039] [Silane compounds (II)] The silane compound (II) is a compound represented by the following formula (3): The silane compound (II) can be used alone or in combination of two or more kinds.

[0040] [ka]

[0041] In the formula (3), X 5 , X 6 , X 7 and X 8 are each independently an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms. 5 , X 6 , X 7 and X 8 At least one of them is an alkoxy group having 1 to 8 carbon atoms.

[0042] X 5 , X 6 , X 7 and X 8 When each of these is an alkyl group, the number of carbon atoms is preferably 1 to 3, and more preferably 1 or 2, in order not to inhibit the reactivity of the alkoxy group. X 5 , X 6 , X 7 and X 8 The number of alkoxy groups is 1 or more, and is preferably 2 or 3, since this will result in stronger crosslinking after coating.

[0043] Specific examples of the silane compound (II) include tetraethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, dimethyldiethoxysilane, and dimethyldimethoxysilane.

[0044] The primer of the present embodiment contains 60 to 150 parts by mass of the silane compound (II) per 100 parts by mass of the acrylic silicone copolymer (I). The amount of the silane compound (II) is preferably 80 to 120 parts by mass per 100 parts by mass of the acrylic silicone copolymer (I).

[0045] By using 60 parts by mass or more of the silane compound (II) per 100 parts by mass of the acrylic silicone copolymer (I), bleeding of the plasticizer from the polyvinyl chloride resin film to the topcoat coating can be effectively suppressed. By using 150 parts by mass or less of the silane compound (II) per 100 parts by mass of the acrylic silicone copolymer (I), the primer layer can be prevented from becoming hard and brittle, and good adhesion to the vinyl chloride resin film can be ensured.

[0046] [Other ingredients] In addition to the acrylic silicone copolymer (I) and the silane compound (II), the primer of the present embodiment may contain other components, such as talc, mica, and silica, within the range that does not impair the effects of the present invention. The proportion of other components (dry solids) in the primer (dry solids) is preferably 40 mass % or less, and more preferably 20 mass % or less.

[0047] [solvent] The primer of the present embodiment contains a solvent for preparing a coating liquid. As the solvent for preparing the coating liquid, the same solvent as that used when the acrylic silicone copolymer (I) is radically solution polymerized can be used. The solvent for preparing the coating liquid may contain the solvent used when the acrylic silicone copolymer (I) is subjected to radical solution polymerization.

[0048] The dry solids concentration of the primer of this embodiment is preferably 20 to 60 mass %, and more preferably 30 to 45 mass %, with the entire primer being 100 mass %. The solids concentration in the preferred range improves the ease of painting. The primer of the present embodiment can be prepared by dissolving or dispersing the acrylic silicone copolymer (I), the silane compound (II), and other components added as necessary in a solvent.

[0049] In the primer of the present embodiment, the acrylic silicone copolymer (I) contains a functional group (2) derived from the monomer (b), and thus undergoes dehydration condensation with the silane compound (II) to form a network structure. Because this reaction is relatively mild, it is easy to ensure sufficient pot life, unlike paints that use epoxy resins and hardeners.

[0050] <Painted items> The coated article of this embodiment has a metal substrate, a polyvinyl chloride resin coating formed on the surface of the metal substrate, a primer layer formed on the polyvinyl chloride resin coating, and a topcoat coating formed on the primer layer.

[0051] Examples of the metal substrate include steel, iron, aluminum, zinc-plated steel, tin-plated steel, etc. Among these, steel is preferred. Steel is an alloy of iron that has been made stronger and tougher by adding carbon, manganese, phosphorus, sulfur, etc. Steel can be either carbon steel, which is made by adding only carbon to iron, or special steel (such as stainless steel), which is made by adding nickel, chromium, etc.

[0052] The shape of the metal substrate is not particularly limited, and can be, for example, a thick plate, a thin plate (sheet), a strip, a bar, a wire rod, a tube, a pipe, or the like.

[0053] The vinyl chloride resin film is formed on at least a part of the surface of the metal substrate. The vinyl chloride resin film generally contains a phthalic acid plasticizer or an adipic acid plasticizer. There is no particular limitation on the thickness of the vinyl chloride resin film, but it is usually in the range of 50 to 1000 μm.

[0054] The primer layer is a coating film obtained by applying the primer according to the above embodiment. Specifically, the acrylic silicone copolymer (I) in the primer according to the above embodiment reacts with the silane compound (II) to harden, and the solvent evaporates to dry the coating film. The primer layer is formed at least on the portion of the vinyl chloride resin film where the topcoat coating film is to be formed.

[0055] The thickness of the primer layer is preferably 2 to 20 μm, more preferably 8 to 15 μm. If the thickness of the primer layer is equal to or greater than the preferred lower limit, bleeding of the plasticizer from the vinyl chloride resin film to the top coat can be effectively suppressed. If the thickness of the primer layer is equal to or less than the preferred upper limit, cracking due to temperature changes can be easily avoided.

[0056] The topcoat coating film is a coating film obtained by applying a topcoat paint onto the primer layer. There is no particular limitation on the type of topcoat paint, but it can be, for example, an acrylic resin paint, a polyester resin paint, an epoxy resin paint, or the like. There is no particular limitation on the thickness of the topcoat film, but it is preferably 8 to 30 μm, and more preferably 10 to 20 μm. The topcoat coating may be one layer or two or more layers, and when two or more layers are used, the compositions of the layers may be the same or different.

[0057] <Method of manufacturing coated articles> The method for producing a coated article of this embodiment is a method in which a metal substrate having a polyvinyl chloride resin film formed on its surface is coated with the primer of the above embodiment, and then coated with a topcoat. The metal substrate and the polyvinyl chloride resin film are the same as those described in the embodiment of the coated article above. The primer can be applied using, for example, a spray, a roller, a brush, a comb, a rubber spatula, or the like.

[0058] The topcoat paint is applied after the applied primer has dried and hardened. The time required for drying and hardening the primer may be, for example, 2 to 24 hours, preferably 6 to 12 hours, at 23°C. The topcoat paint can be applied using, for example, a spray, a roller, a brush, a comb trowel, a rubber spatula, or the like. When forming a topcoat film of two or more layers, the topcoat paint may be applied on top of the lower topcoat paint after the lower topcoat paint has dried and hardened. EXAMPLES

[0059] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0060] <Raw materials> The raw materials used in each example are as follows: [Monomer (a)] Methyl methacrylate: manufactured by Kyoeisha Chemical Co., Ltd., R in the above formula (1) 1 is a methyl group, R 2 is a methyl group. Butyl methacrylate: manufactured by Kyoeisha Chemical Co., Ltd., R in the above formula (1) 1 is n-butyl group, R 2 is a methyl group. Butyl acrylate: manufactured by Kyoeisha Chemical Co., Ltd., R in the above formula (1) 1 is n-butyl group, R 2 is a hydrogen atom. Cyclohexyl methacrylate: manufactured by Kyoeisha Chemical Co., Ltd., R in the above formula (1) 1 is a cyclohexyl group, R 2 is a methyl group. Methacrylic acid: manufactured by Kyoeisha Chemical Co., Ltd., R in the above formula (1) 1 is a hydrogen atom, R 2 is a methyl group.

[0061] [Monomer (b)] 3-Methacryloxypropyltrimethoxysilane: manufactured by Shin-Etsu Chemical Co., Ltd., X in the formula (4) 1 , X 2 and X 3 is a methoxy group, and R 3 A compound in which is a methyl group and Q is a propylene group. 3-Methacryloxypropylmethyldiethoxysilane: manufactured by Shin-Etsu Chemical Co., Ltd., X in the formula (4) 1 , is a methyl group, X 2 and X 3 is an ethoxy group, and R 3 A compound in which is a methyl group and Q is a propylene group. 3-Methacryloxypropyltriethoxysilane: manufactured by Shin-Etsu Chemical Co., Ltd., X in the formula (4) 1 , X 2 and X 3 is an ethoxy group, and R 3 A compound in which is a methyl group and Q is a propylene group.

[0062] [Silane compounds (II)] Methyltrimethoxysilane: manufactured by Kanto Chemical Co., Ltd., X in the formula (3) 5 is a methyl group, and X 6 , X 7 and X 8 is a methoxy group. Dimethyldimethoxysilane: manufactured by Tokyo Chemical Industry Co., Ltd., X in the formula (3) 5 and X 6 is a methyl group, and X 7 and X 8 is a methoxy group.

[0063] [solvent] Ethyl acetate: manufactured by Taishin Chemical Co., Ltd. Methyl isobutyl ketone: manufactured by Taishin Chemical Co., Ltd. Butyl acetate: manufactured by Taishin Chemical Co., Ltd. [Polymerization initiator] 2,2'-Azobisisobutyronitrile: manufactured by Tokyo Chemical Industry Co., Ltd.

[0064] <Preparation of acrylic silicone copolymer> [(I-1)] In a 1L round bottom flask equipped with a stirrer, 38g of methyl methacrylate, 13.8g of butyl methacrylate, 15g of butyl acrylate, 31g of cyclohexyl methacrylate, 2g of methacrylic acid, 0.2g of 3-methacryloxypropyltrimethoxysilane, and 250g of ethyl acetate were charged, and the mixture was heated with stirring, and 0.5g of 2,2'-azobisisobutyronitrile was charged at 75°C to start the reaction. The mixture was reacted at an internal temperature of 75°C for 5 hours and then cooled to obtain an acrylic silicone copolymer (I-1).

[0065] [(I-2)~(I-12)] Acrylic silicone copolymers (I-2) to (I-12) were obtained in the same manner as for the acrylic silicone copolymer (I-1), except that the amounts (g) of the raw materials used were changed as shown in Table 1.

[0066] [Glass transition temperature Tg] The glass transition temperatures of the acrylic silicone copolymers (I-1) to (I-12) were measured by gel permeation chromatography (GPC). The results are shown in Table 1 and Tables 2-4.

[0067] [Table 1]

[0068] <Primer preparation> The other raw materials shown in Tables 2 to 4 were mixed and dissolved in a disperser in the amounts (g) shown in Tables 2 to 4 with 100 g of any of the prepared acrylic silicone copolymers to obtain the primers of each example. Among the solvents, ethyl acetate was the solvent (internal solvent) used in the preparation of the acrylic silicone copolymer. In Tables 2 to 4, "(II) / (I)×100" is the amount of silane compound (II) blended relative to 100 parts by mass of acrylic silicone copolymer (I).

[0069] <Evaluation of primers> [Creating test specimens] The obtained primer of each example was spray-coated onto a steel plate having a 50 mm wide and 100 mm long polyvinyl chloride resin film (film thickness: 150 μm) formed on its surface, so that the film thickness when dried would be 5 μm, and then dried at room temperature for 24 hours. On the dried coating, 150 g / m of acrylic resin paint (Acretan MF: manufactured by Fujikura Kasei Co., Ltd.) was applied as a topcoat. 2 The coating was applied in a coating amount of 100g, and the coating was dried at room temperature for 24 hours to prepare test specimens for each example.

[0070] [Initial adhesion test] The adhesion to the test piece was evaluated according to JIS K 5600-5-6:1999 with the cutting edge spacing set to 2 mm and based on the following criteria. The results are shown in Tables 2 to 4. ○: Only small peeling of the coating at the intersections of the cuts. △: Peeled area is 15% or more and less than 35%. ×: Peeled area is 35% or more.

[0071] [Migration test] The test pieces were left for 72 hours under conditions of a temperature of 25° C. and a humidity of 50% RH, and the surface condition was observed and evaluated according to the following criteria. The results are shown in Tables 2 to 4. ○: No abnormalities. △: There is a slight tack, but it does not affect the practical use. ×: The coating film is sticky and softened, or dirt adheres to the coating film and cannot be removed.

[0072] [Table 2]

[0073] [Table 3]

[0074] [Table 4]

[0075] As shown in Tables 2 and 3, the primers of Examples 1 to 12 obtained good results in both the initial adhesion test and the migration test. In contrast, the primers of Comparative Examples 1 to 5 obtained poor results in either the initial adhesion test or the migration test.

Claims

1. A primer that is applied to a metal substrate having a polyvinyl chloride resin film formed on the surface thereof before applying a topcoat paint, Contains an acrylic silicone copolymer (I) and a silane compound (II), The acrylic silicone copolymer (I) is a copolymer of a monomer (a) represented by the following formula (1) and a monomer (b) having a group represented by the following formula (2) and a polymerizable unsaturated group, the ratio of the monomer (b) to the total amount of the monomer (a) and the monomer (b) is 0.2 to 10.0 mass%, The glass transition temperature Tg of the acrylic silicone copolymer (I) is 20° C. or higher, The silane compound (II) is a compound represented by the following formula (3): A primer comprising 60 to 150 parts by mass of the silane compound (II) per 100 parts by mass of the acrylic silicone copolymer (I). 【Chemistry 1】 (In the above formula (1), R １ represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a cycloalkyl group having 6 carbon atoms; R ２ represents a hydrogen atom or a methyl group.) 【Chemistry 2】 (In the above formula (2), X １ , X ２ and X ３ are each independently an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms. １ , X ２ and X ３ At least one of the groups is an alkoxy group having 1 to 8 carbon atoms. 【Chemistry 3】 (In the formula (3), X ５ , X ６ , X ７ and X ８ are each independently an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms. ５ , X ６ , X ７ and X ８ At least one of the groups is an alkoxy group having 1 to 8 carbon atoms.

2. The monomer (a) is represented by R １ is a hydrogen atom, and a monomer (a1) selected from (meth)acrylic acid, １ and a monomer (a2) selected from (meth)acrylic acid esters, wherein R is an alkyl group having 1 to 12 carbon atoms, and R is a cycloalkyl group having 6 carbon atoms.

3. A metal substrate, a vinyl chloride resin film formed on a surface of the metal substrate, a primer layer formed on the vinyl chloride resin film, and a topcoat film formed on the primer layer, A coated article, wherein the primer layer is a coating film obtained by applying the primer according to claim 1 or 2.

4. The coated article of claim 3 , wherein the metallic substrate is steel.

5. A method for producing a coated article, comprising coating a metal substrate having a polyvinyl chloride resin film formed on its surface with the primer according to claim 1 or 2, and then coating the substrate with a topcoat paint.

6. The method of claim 5, wherein the metal substrate is a steel material.

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