Aqueous coating composition and method for manufacturing a coating layer

Abstract

To provide an aqueous coating composition that exhibits superior adhesion and weather resistance.SOLUTION: An aqueous coating composition includes a curable resin composition with water as the medium, and a tackifier, where the tackifier includes a polysiloxane resin, which includes a constitutional unit derived from a specific monomer with a radical-polymerizable group, and water.SELECTED DRAWING: None

Description

【Technical Field】 【0001】 The present invention relates to an aqueous coating composition and a method for producing a coating layer. 【Background Art】 【0002】 Conventionally, coating agents have been used for the purpose of beautifying and protecting structures such as buildings, civil engineering works, and vehicles. Among the compositions constituting the coating agent, a coating composition (aqueous coating composition) using water as a medium that can be stably dispersed or dissolved (aqueous) in an aqueous medium has been demanded from the viewpoint of environmental compatibility and the like. 【0003】 By the way, the aqueous coating composition has had a problem that its adhesion to the base material constituting the structure is inferior to that of a solvent-based coating composition using an organic solvent as a medium. 【0004】 Therefore, as a technique for improving the adhesion to the base material, for example, Patent Document 1 and Patent Document 2 describe a coating composition containing an adhesion promoter. 【Prior Art Documents】 【Patent Documents】 【0005】 【Patent Document 1】 International Publication No. 2017 / 191789 【Patent Document 2】 Japanese Patent No. 7075731 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0006】 However, the techniques described in Patent Document 1 and Patent Document 2 have room for improvement from the viewpoint of the weather resistance of the obtained coating layer and the like. 【0007】 Therefore, the present invention aims to provide a water-based coating composition that contains an adhesion-improving agent and exhibits excellent adhesion and weather resistance. [Means for solving the problem] 【0008】 As a result of diligent research to solve the aforementioned problems, the inventors have discovered for the first time that a water-based coating composition can be made to have excellent adhesion and weather resistance by including a water-based curable resin composition and an adhesion-improving agent composed of specific components, and have completed the present invention. 【0009】 Accordingly, one aspect of the present invention is an aqueous coating composition comprising a water-curable resin composition and an adhesion promoter, wherein the adhesion promoter contains a polysiloxane resin and water, and the polysiloxane resin has a polymer as a constituent unit that includes a constituent unit derived from a monomer having a radical polymerizable group, and the monomer comprises (i) a monomer having a salt structure consisting of an acid and a base, being soluble in water and not forming micelles in water, and (ii) a monomer capable of forming micelles in water, the aqueous coating composition (hereinafter referred to as "this aqueous coating composition"). 【0010】 Furthermore, one aspect of the present invention is a method for producing a coating layer, comprising the step of applying an aqueous coating composition, which comprises a water-curable resin composition and an adhesion promoter, to a substrate, wherein the adhesion promoter contains a polysiloxane resin (A) and water, and the polysiloxane resin (A) has a polymer as a constituent unit that includes a constituent unit derived from a monomer having a radical polymerizable group, and the monomer includes (i) a monomer having a salt structure consisting of an acid and a base, which is soluble in water and does not form micelles in water, and (ii) a monomer that can form micelles in water, and is a method for producing a coating layer (hereinafter referred to as "the present production method"). [Effects of the Invention] 【0011】 According to one aspect of the present invention, a water-based coating composition containing an adhesion promoter and exhibiting excellent adhesion and weather resistance can be provided. [Modes for carrying out the invention] 【0012】 One embodiment of the present invention will be described in detail below. Unless otherwise specified in this specification, "A to B" representing a numerical range means "greater than or equal to A and less than or equal to B". Furthermore, all references cited in this specification are incorporated herein by reference. 【0013】 [1. Outline of the present invention] As described above, conventional techniques have been known to include adhesion-improving agents in coating compositions in order to improve adhesion to a substrate. For example, the inventions described in Patent Documents 1 and 2 disclose curable resin compositions that contain compounds having organic functional groups such as epoxy groups or isocyanate groups as adhesion-improving agents. 【0014】 However, it was difficult to apply the technology described in Patent Document 1 to water-based coating agents. Furthermore, the inventors have newly discovered that in the technologies described in Patent Documents 1 and 2, adding an adhesion promoter to the coating composition can sometimes lead to a problem where the weather resistance of the resulting coating layer deteriorates. 【0015】 Therefore, the inventors conducted diligent research to solve the aforementioned problems and, as a result, discovered for the first time that a water-based coating composition exhibits excellent adhesion and weather resistance by containing a water-based curable resin composition and an adhesion-improving agent composed of specific components. Specifically, they succeeded in obtaining the following findings: A water-based coating composition comprising a water-curable resin composition and an adhesion promoter, wherein the adhesion promoter contains a polysiloxane resin and water, and the polysiloxane resin has a polymer as a constituent unit that includes a constituent unit derived from a monomer having a radical polymerizable group, and the monomer includes (i) a monomer having a salt structure consisting of an acid and a base, which is soluble in water and does not form micelles in water, and (ii) a monomer that can form micelles in water, thereby obtaining a water-based coating composition with excellent adhesion and weather resistance. 【0016】 Thus, the fact that the adhesion and weather resistance of a water-based coating composition can be improved by including a curable resin composition having a specific composition and an adhesion-improving agent (especially an adhesion-improving agent) is something that could not have been predicted from conventional knowledge, and therefore the present invention is extremely excellent. 【0017】 Furthermore, the above configuration reduces water and soil pollution compared to conventional technologies by having a low or no organic solvent content. Therefore, it can contribute to achieving goals such as Goal 15 of the United Nations' Sustainable Development Goals (SDGs), "Protect and restore life on land." 【0018】 [2. Water-based coating compositions] This aqueous coating composition comprises a water-based curable resin composition and an adhesion promoter, wherein the adhesion promoter contains a polysiloxane resin and water, and the polysiloxane resin has a polymer as a constituent unit that includes a constituent unit derived from a monomer having a radical polymerizable group, and the monomer includes (i) a monomer having a salt structure consisting of an acid and a base, which is soluble in water and does not form micelles in water, and (ii) a monomer that can form micelles in water. 【0019】 This aqueous coating composition has the advantage of having excellent adhesion and weather resistance due to the aforementioned structure. 【0020】 In this specification, "water-based coating composition" refers to a coating composition that uses water as a medium. In this specification, "water-based coating composition" refers to a coating composition that contains 5% by weight or more of water in 100% by weight of the coating composition. The water content is preferably 10% by weight or more, more preferably 20% by weight or more, and particularly preferably 50% by weight or more, in 100% by weight of the coating composition. This configuration has the advantage that the resulting coating composition has good workability. 【0021】 Furthermore, in this specification, a coating composition refers to a composition that can protect against scratches and dirt, and provide an aesthetic appearance by forming a film on the surface of an object to be coated. 【0022】 (2-1. Water-based curable resin compositions) This aqueous coating composition includes a water-based curable resin composition. In this specification, "a water-based curable resin composition according to one embodiment of the present invention" may be referred to as "this curable resin composition." 【0023】 In this specification, "water-based curable resin composition" refers to a curable resin composition containing 5% by weight or more of water in 100% by weight of the curable resin composition. The water content is preferably 10% by weight or more, more preferably 20% by weight or more, and particularly preferably 50% by weight or more, in 100% by weight of the curable resin composition. This configuration has the advantage of having good workability. 【0024】 The curable resin composition preferably contains one or more selected from the group consisting of acrylic silicone resin emulsion, acrylic resin emulsion, styrene acrylic resin emulsion, acrylic urethane resin emulsion, vinyl acetate resin emulsion, and fluororesin emulsion such as polytetrafluoroethylene. Furthermore, from the viewpoint of weather resistance of the resulting water-based coating composition, the curable resin composition is more preferably an acrylic silicone resin emulsion. 【0025】 The curable resin composition preferably contains a constituent unit derived from a radically polymerizable unsaturated monomer (x) and a constituent unit derived from a radically polymerizable unsaturated monomer (y) having a hydrolyzable silyl group. This configuration has the advantage that the resulting cured film (coating layer) has high weather resistance. 【0026】 The radical polymerizable unsaturated monomer (x) is not particularly limited, but examples include acrylic monomers, specifically methyl (meth)acrylate, ethyl (meth)acrylate, iso-propyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, tert-butyl (meth)acrylate, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)methacrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, isobonyl (meth)acrylate, and the like. 【0027】 The radical polymerizable unsaturated monomer (y) having a hydrolyzable silyl group is not particularly limited, but for example, formula R 1 R 2 (3-n) SiX n (In the formula, R 1 R is a monovalent organic group having a polymerizable double bond. 2The organosilicon compound is represented by (where is an alkyl group having 1 to 4 carbon atoms, X is an alkoxyl group having 1 to 4 carbon atoms, and n is 1 to 3), and it is preferable that the compound has 2 or 3 alkoxyl groups and a reactive double bond. Specific examples include vinyltrimethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, vinyltriethoxysilane, γ-(meth)acryloxypropyltriethoxysilane, γ-(meth)acryloxypropyltripropoxysilane, γ-(meth)acryloxypropyltributoxysilane, vinylmethyldimethoxysilane, γ-(meth)acryloxypropylmethyldimethoxysilane, vinylmethyldiethoxysilane, γ-(meth)acryloxypropylmethyldiethoxysilane, γ-( Examples include meth)acryloxypropylmethyldipropoxysilane, γ-(meth)acryloxypropylmethyldibutoxysilane, vinyldimethylmethoxysilane, vinyldimethylethoxysilane, γ-(meth)acryloxypropyldimethylethoxysilane, γ-(meth)acryloxypropyldimethylmethoxysilane, γ-(meth)acryloxypropyldimethylpropoxysilane, and γ-(meth)acryloxypropyldimethylbutoxysilane, and these can be used individually or in combination of two or more. In particular, from the viewpoint of storage stability of the emulsion, X has 2 to 4 carbon atoms. 【0028】 In one embodiment of the present invention, the content of constituent units derived from the radically polymerizable unsaturated monomer (y) is preferably 0.1 to 20% by weight, more preferably 0.5 to 15% by weight, and even more preferably 1.0 to 10% by weight, based on 100% by weight of the curable resin composition. This configuration has the advantage that the resulting aqueous coating composition has excellent weather resistance and is suitable for storage. 【0029】 Furthermore, this curable resin composition may contain other components besides the constituent units described above. For other components and methods for producing this curable resin composition, please refer to the provisions of Japanese Patent No. 7075731. 【0030】 (2-2. Adhesion-enhancing agents) In one embodiment of the present invention, the adhesion promoter contains a polysiloxane-based resin and water, and has a polymer containing a structural unit derived from a monomer having a radically polymerizable group as a structural unit of the polysiloxane-based resin. The monomer includes (i) a monomer having a salt structure composed of an acid and a base, being soluble in water and not forming micelles in water, and (ii) a monomer capable of forming micelles in water. In the present specification, the "adhesion promoter according to one embodiment of the present invention" may be referred to as the "present adhesion promoter". 【0031】 <Polysiloxane-based resin> In one embodiment of the present invention, the polysiloxane-based resin has a polymer containing a structural unit derived from a monomer having a radically polymerizable group as a structural unit. The monomer includes (i) a monomer having a salt structure composed of an acid and a base, being soluble in water and not forming micelles in water, and (ii) a monomer capable of forming micelles in water. In the present specification, the "polysiloxane-based resin according to one embodiment of the present invention" may be referred to as the "present polysiloxane-based resin". 【0032】 By having the above-described configuration, the present polysiloxane-based resin can be stably dispersed or dissolved (aqueous phase formation) in an aqueous medium, and when in aqueous phase formation, the viscosity can be easily adjusted, and it can be suitably used as an adhesion promoter. 【0033】 In the present specification, the "polysiloxane-based resin" means a resin containing a polysiloxane structure as a main component. The polysiloxane-based resin is not particularly limited as long as it satisfies the above definition. For example, resins mainly composed of a polysiloxane structure obtained by dehydration condensation of a single compound represented by the following general formula (IV) or co-condensation of a plurality of compounds represented by the following general formula (IV) can be mentioned: R 1 a R 2 b -Si-(OR 3 ) 4-a-b ···(IV) (In the formula, R 1R is a substituted alkyl group having 1 to 10 carbon atoms having a polymerizable unsaturated group, an alkenyl group, or an aryl group having a polymerizable unsaturated group and optionally having other substituents. 2 Each of these is independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group, and R 3 Each of these is independently either a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, where a is an integer from 1 to 3, b is an integer from 0 to 2, and a+b is an integer from 1 to 3. Furthermore, in one embodiment of the present invention, the polysiloxane resin may be a resin mainly composed of a polysiloxane structure, obtained by co-condensing a single compound or a plurality of compounds represented by the above general formula (IV) with a single compound or a plurality of compounds represented by the following general formula (III): R 4 n -Si-(OR 5 ) 4-n ...(III) (In the formula, R 4 Each of these is independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group, and R 4 If there are multiple, they may be the same or different, R 5 Each of these is independently either a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and n is an integer from 0 to 3. 【0034】 In this specification, the polysiloxane structure, which is the main component of a polysiloxane resin, that is, the structural unit formed by condensing monomers having hydrolyzable silyl groups, may be referred to as the "main chain," and the structural unit consisting of monomers having radically polymerizable groups that are bonded to the main chain by radical polymerization may be referred to as the "side chain." 【0035】 The side chains of this polysiloxane resin consist of a polymer containing constituent units derived from monomers having radical polymerizable groups. The monomers constituting the side chains of this polysiloxane resin are not particularly limited as long as they include (i) monomers having a salt structure consisting of an acid and a base, being soluble in water and not forming micelles in water, and (ii) monomers capable of forming micelles in water. The side chains of this polysiloxane resin may consist only of the monomers described in (i) and (ii), or may contain other monomers. In the monomers constituting the side chains of one embodiment of the present invention, monomers other than those described in (i) and (ii) are preferably monomers that do not have hydrolyzable silyl groups, and optionally may include monomers that have hydrolyzable silyl groups. Therefore, the polysiloxane resin can also be expressed as a preferred example as follows: a polysiloxane resin having a side chain made of a polymer containing a constituent unit derived from a monomer having a radical polymerizable group, wherein the constituent units of the side chain include a constituent unit (b) derived from a monomer (B) that (does not have a polyoxyalkylene structure) has a salt structure consisting of an acid and a base and a radical polymerizable group, and does not have a hydrolyzable silyl group, is soluble in water, and does not form micelles in water, and a constituent unit (c) derived from a monomer (C) that (has a polyoxyalkylene structure) has a structure that can form micelles in water and a radical polymerizable group, and does not have a hydrolyzable silyl group. 【0036】 In one embodiment of the present invention, the polysiloxane resin preferably comprises a constituent unit (a) derived from a silane compound (A) having a radically polymerizable unsaturated group and a hydrolyzable silyl group; a constituent unit (b) derived from a monomer (B) having a salt structure consisting of an acid and a base and a radically polymerizable group, but lacking a hydrolyzable silyl group, being soluble in water, and not forming micelles in water; and a constituent unit (c) derived from a monomer (C) having a polyoxyalkylene structure and a radically polymerizable group, lacking a hydrolyzable silyl group, and capable of forming micelles in water. In one embodiment of the present invention, it is preferable that the polysiloxane resin has constituent unit (a) forming the main chain and constituent units (b) and (c) forming the side chains. 【0037】 Furthermore, in one embodiment of the present invention, the polysiloxane resin, in addition to (A) to (C) above, optionally includes the following general formula (III) as a main chain constituent unit: R 4 n -Si-(OR 5 ) 4-n ...(III) (In the formula, R 4 Each of these is independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group, and R 4 If there are multiple, they may be the same or different, R 5 Each of these is independently either a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and n is an integer from 0 to 3. It is more preferable to further include a constituent unit (d) derived from the silane compound (D) shown in the diagram. 【0038】 In the following, "constituent unit (a) derived from a silane compound (A) having a radically polymerizable unsaturated group and a hydrolyzable silyl group" will be simply referred to as "constituent unit (a)," and "constituent unit (b) derived from a monomer (B) having a salt structure consisting of an acid and a base and a radically polymerizable group, but lacking a hydrolyzable silyl group, being soluble in water, and not forming micelles in water" will be simply referred to as "constituent unit (b)," and "polyoxyalkylene structure and radical heavy A constituent unit (c) derived from a monomer (C) having a polymeric group and lacking a hydrolyzable silyl group, and capable of forming micelles in water, is simply referred to as "constituent unit (c)," a constituent unit (d) derived from a silane compound (D) represented by general formula (III) is simply referred to as "constituent unit (d)," and a constituent unit (e) derived from a monomer (E) having a radical polymerizable group other than (A), (B), and (C) is simply referred to as "constituent unit (e)." Furthermore, in the following, "silane compound (A) having a radically polymerizable unsaturated group and a hydrolyzable silyl group" will be simply referred to as "silane compound (A)" or "monomer (A)", "monomer (B) having a salt structure consisting of an acid and a base and a radically polymerizable group, but lacking a hydrolyzable silyl group, being soluble in water, and not forming micelles in water" will be simply referred to as "monomer (B)", "monomer (C) having a polyoxyalkylene structure and a radically polymerizable group, but lacking a hydrolyzable silyl group, and capable of forming micelles in water" will be simply referred to as "monomer (C)", "silane compound (D) represented by general formula (III)" will be simply referred to as "silane compound (D)" or "monomer (D)", and "monomer (E) having a radically polymerizable group other than (A), (B), and (C)" will be simply referred to as "monomer (E)". 【0039】 (Constituent unit (a)) The constituent unit (a) is derived from a silane compound (A) having a radically polymerizable unsaturated group and a hydrolyzable silyl group. 【0040】 Silane compound (A) having a radically polymerizable unsaturated group and a hydrolyzable silyl group is given by the following general formula (IV): R 1 a R2 b -Si-(OR 3 ) 4-a-b ...(IV) (In the formula, R 1 R is a substituted alkyl group having 1 to 10 carbon atoms having a polymerizable unsaturated group, an alkenyl group, or an aryl group having a polymerizable unsaturated group and optionally having other substituents. 2 Each of these is independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group, and R 3 Each of these is independently either a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, where a is an integer from 1 to 3, b is an integer from 0 to 2, and a+b is an integer from 1 to 3. It is a silane compound having a hydrolyzable silyl group, represented by [formula]. 【0041】 R in general formula (IV) 1 These are substituted alkyl groups, alkenyl groups, or unsubstituted or substituted aryl groups having radically polymerizable unsaturated groups, all having 1 to 10 carbon atoms. Examples of radically polymerizable unsaturated groups include (meth)acryloyl groups. 【0042】 R 1Examples of silane compounds (A) in which is an alkyl group having a radically polymerizable unsaturated group include (meth)acryloxymethyltrimethoxysilane, (meth)acryloxymethylmethyldimethoxysilane, (meth)acryloxymethyldimethylmethoxysilane, (meth)acryloxymethyltriethoxysilane, (meth)acryloxymethylmethyldiethoxysilane, (meth)acryloxymethyldimethylethoxysilane, 2-(meth)acryloxyethyltrimethoxysilane, 2-(meth)acryloxyethylmethyldimethoxysilane, 2- (meth)acryloxyethyldimethylmethoxysilane, 2-(meth)acryloxyethyltriethoxysilane, 2-(meth)acryloxyethylmethyldiethoxysilane, 2-(meth)acryloxyethyldimethylethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropylmethyldimethoxysilane, γ-(meth)acryloxypropyldimethylmethoxysilane, γ-(meth)acryloxypropyltriethoxysilane, γ-(meth)acryloxypropylmethyldiethoxysilane, γ- (meth)acryloxypropyldimethylethoxysilane, 4-(meth)acryloxybutyltrimethoxysilane, 4-(meth)acryloxybutylmethyldimethoxysilane, 4-(meth)acryloxybutyldimethylmethoxysilane, 4-(meth)acryloxybutyltriethoxysilane, 4-(meth)acryloxybutylmethyldiethoxysilane, 4-(meth)acryloxybutyldimethylethoxysilane, 5-(meth)acryloxypentyltrimethoxysilane, 5-(meth)acryloxypentylmethyldimethoxysilane, 5-(meth) (T) Acryloxypentyl dimethyl methoxysilane, 5-(meth)acryloxypentyl triethoxysilane, 5-(meth)acryloxypentyl methyl diethoxysilane, 5-(meth)acryloxypentyl dimethyl ethoxysilane, 6-(meth)acryloxyhexyl trimethoxysilane, 6-(meth)acryloxyhexyl methyl dimethoxysilane, 6-(meth)acryloxyhexyl dimethyl methoxysilane, 6-(meth)acryloxyhexyl triethoxysilane, 6-(meth)acryloxyhexyl methyl diethoxysilane,Examples include 6-(meth)acryloxyhexyldimethylethoxysilane. 【0043】 R 1 Examples of silane compounds (A) in which the group is an alkenyl group include vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, and vinyldimethylethoxysilane. 【0044】 R 1 Examples of silane compounds (A) in which the aryl group has a polymerizable unsaturated group and may optionally have other substituents include p-styryltrimethoxysilane, p-styrylmethyldimethoxysilane, p-styryldimethylmethoxysilane, p-styryltriethoxysilane, p-styrylmethyldiethoxysilane, and p-styryldimethylethoxysilane. 【0045】 Among these, in terms of radical polymerization reactivity, R 1 (Meth)acryloyl group-substituted alkyl groups are preferred. 【0046】 R in general formula (IV) 2 Each of these is independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group. 【0047】 R in general formula (IV) 2 Specific examples of alkyl groups in this context include, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, amyl group, isoamyl group, hexyl group, cyclohexyl group, cyclohexylmethyl group, cyclohexylethyl group, heptyl group, isoheptyl group, n-octyl group, isooctyl group, and 2-ethylhexyl group. 【0048】 R in general formula (IV) 2 Specific examples of aryl groups in this context include, for example, phenyl, naphthyl, and benzyl groups. 【0049】 R in general formula (IV) 2 When a is 1 and b is 1, it is preferable that it is a methyl group. 【0050】 R in general formula (IV) 3 The group is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and examples include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, pentyl group, hexyl group, amyl group, isoamyl group, hexyl group, cyclohexyl group, cyclohexylmethyl group, cyclohexylethyl group, heptyl group, isoheptyl group, octyl group, n-octyl group, isooctyl group, 2-ethylhexyl group, nonyl group, decyl group, etc. 【0051】 From the viewpoint of easily condensing silane compound (A) with other silane compounds that do not have radical polymerizable unsaturated groups (silane compound (D)), the R in general formula (IV) 2 and R 3 The alkyl group preferably has 1 to 3 carbon atoms, and most preferably 1 carbon atom. 【0052】 In one embodiment of the present invention, the content of constituent unit (a) is, for example, 1% by weight or more, preferably 2% by weight or more, based on 100% by weight of the total amount of the polysiloxane resin. When the content of constituent unit (a) is within the above range, graft polymerization can be sufficiently performed directly or indirectly with constituent unit (b) and / or constituent unit (c), and as a result, a polysiloxane resin that can be stably dispersed or dissolved (water-based) in an aqueous medium can be obtained. Furthermore, the upper limit of the content of constituent unit (a) is not particularly limited as long as the effects of the present invention are achieved, but for example, it is 10% by weight or less, preferably 8% by weight or less, and more preferably 5% by weight or less. 【0053】 (Constituent unit (b)) The constituent unit (b) is derived from monomer (B), which has a salt structure consisting of an acid and a base, a radical polymerizable group, does not have a hydrolyzable silyl group, is soluble in water, and does not form micelles in water. 【0054】 In this specification, "salt structure" refers to the structure of a neutral salt obtained by neutralizing an acid and a base. Here, the acid used for neutralization may be a strong acid or a weak acid. Similarly, the base used for neutralization may be a strong base or a weak base. 【0055】 In one embodiment of the present invention, the salt structure may be, for example, the structure of a neutral salt of a strong acid and a strong base, the structure of a neutral salt of a strong acid and a weak base, the structure of a neutral salt of a weak acid and a strong base, or the structure of a neutral salt of a weak acid and a weak base. More specific salt structures include, for example, sodium sulfonate, potassium sulfonate, calcium sulfonate, sodium nitrate, potassium nitrate, calcium nitrate, etc. (structure of a neutral salt of a strong acid and a strong base), ammonium sulfonate, ammonium nitrate, etc. (structure of a neutral salt of a strong acid and a weak base), sodium acetate, potassium acetate, calcium acetate, sodium phosphate, potassium phosphate, calcium phosphate, etc. (structure of a neutral salt of a weak acid and a strong base), ammonium acetate, ammonium phosphate, etc. (structure of a neutral salt of a weak acid and a weak base), etc. In one embodiment of the present invention, the salt structure is preferably sodium sulfonate. 【0056】 In this specification, "water soluble" means that when an aqueous solution is prepared by adding 1 g of the monomer to 10 g of water at 25°C, stirring it thoroughly, letting it stand for one week under conditions of 25°C, and observing its appearance visually, no precipitate, dispersion, or separation of layers is observed in the aqueous solution, and it is transparent. 【0057】 In one embodiment of the present invention, the content of constituent unit (b) is, for example, 1% by weight or more, preferably 2% by weight or more, and more preferably 4% by weight or more, based on 100% by weight of the total amount of the polysiloxane resin. When the content of constituent unit (b) is within the above range, it has the effect of being uniformly dispersed or soluble in water. Furthermore, the upper limit of the content of constituent unit (b) is not particularly limited as long as the effects of the present invention are achieved, but for example, it is 20% by weight or less, preferably 15% by weight or less, and more preferably 10% by weight or less. 【0058】 In this specification, "stable dispersion or dissolution in an aqueous medium" means that no "precipitate" is formed when a solution containing polysiloxane resin is evaluated by the following method: An aqueous solution of polysiloxane resin prepared by the method described in the examples is left to stand for one week at 25°C, and its appearance is evaluated by visual observation. 【0059】 In other words, "stable dispersion or dissolution in an aqueous medium" means that when a solution containing polysiloxane resin is evaluated using the method described above, the solution containing polysiloxane resin is evaluated as uniformly "colorless and transparent," "bluish-white and transparent," or "white dispersion." If "precipitates" are observed, it does not qualify as "stable dispersion or dissolution in an aqueous medium." 【0060】 Monomer (B) is a monomer that has a salt structure composed of an acid and a base and radical polymerizable groups, does not have hydrolyzable silyl groups, is soluble in water, and does not form micelles in water. The radical polymerizable groups in monomer (B) undergo radical polymerization with the radical polymerizable groups in monomer (A), forming graft chains derived from monomer (B) on the polysiloxane main chain. Because monomer (B) has a salt structure composed of an acid and a base and is soluble in water, this polysiloxane-based resin can be stably dispersed or dissolved in an aqueous medium. 【0061】 The radical polymerizable unsaturated group in monomer (B) is not particularly limited as long as it can contribute to radical polymerization with monomer (A). Examples of radical polymerizable unsaturated groups in monomer (B) include (meth)acryloyl groups, (meth)acrylamide groups, and vinyl groups. From the viewpoint of high reactivity and versatility, (meth)acryloyl groups or (meth)acrylamide groups are preferred. 【0062】 The monomer (B) is not particularly limited as long as it has a salt structure consisting of an acid and a base and a radical polymerizable group, but examples include sodium sulfoethyl methacrylate, sodium acrylamide-t butylsulfonate, sodium 2-(methacryloyloxy)ethanesulfonate, sodium acrylamide-t butylsulfonate, potassium 2-(methacryloyloxy)ethanesulfonate, potassium acrylamide-t butylsulfonate, calcium 2-(methacryloyloxy)ethanesulfonate, calcium acrylamide-t butylsulfonate, ammonium sulfoethyl methacrylate, ammonium acrylamide-t butylsulfonate, ammonium 2-(methacryloyloxy)ethanesulfonate, ammonium acrylamide-t butylsulfonate, sodium acrylate, potassium acrylate, calcium acrylate, ammonium acrylate, sodium methacrylate, potassium methacrylate, calcium methacrylate, and ammonium methacrylate. 【0063】 Furthermore, monomer (B) can be obtained as a commercial product. Examples of such commercial products include "Antox MS-2N-D" manufactured by Nippon Emulsifier Co., Ltd., "ATBS-Na" manufactured by Toagosei Co., Ltd., and "Sodium Acrylate" and "Potassium Acrylate" manufactured by Asada Chemical Industries, Ltd. 【0064】 Furthermore, whether or not a monomer is "capable of forming micelles in water" is measured by the method described in the section on (constituent unit (c)). 【0065】 (Constituent unit (c)) The constituent unit (c) is derived from monomer (C), which has radical polymerizable groups but lacks hydrolyzable silyl groups and is capable of forming micelles in water. The radical polymerizable groups in monomer (C) undergo radical polymerization directly or indirectly with the radical polymerizable groups in monomer (A), forming graft chains derived from monomer (C) on the polysiloxane main chain. Because this polysiloxane resin has constituent unit (c), viscosity adjustment is easily made when the polysiloxane resin is converted to an aqueous solution by forming micelles, making it suitable for use as an adhesion promoter. 【0066】 In this specification, "micelle" refers to an aggregate formed by the association of amphiphilic molecules through hydrophobic interactions. Here, an amphiphilic molecule is defined as a molecule having both a hydrophobic group and a hydrophilic group within it. Therefore, a "structure capable of forming micelles in water" refers to a structure having both a hydrophobic group and a hydrophilic group within it. 【0067】 In one embodiment of the present invention, monomer (C) may be an amphiphilic molecule that does not have a hydrolyzable silyl group. 【0068】 The determination of whether or not "micelle formation is possible in water" is made by the following method: Add 1 g of the monomer in question to a two-layer solution containing 10 g of water and 2 g of butyl acetate, stir thoroughly, and after standing for 12 hours, if a uniform turbidity is observed, the monomer in question is judged to be capable of forming micelles in water. If, after standing for 12 hours, a clear layer of water and butyl acetate separates, the monomer in question is judged not to form micelles in water (micelle formation is impossible). 【0069】 The monomer (C) is not particularly limited as long as it has radical polymerizable groups, a structure that forms micelles in water (i.e., a structure having both hydrophobic and hydrophilic groups within the molecule), and does not have hydrolyzable silyl groups. 【0070】 The hydrophobic group within the monomer (C) is not particularly limited, but examples include alkyl groups having 3 or more carbon atoms and having radical polymerizable groups, aryl groups, etc. 【0071】 The hydrophilic groups within the monomer (C) are not particularly limited, but examples include anionic hydrophilic groups such as sulfonates, carboxylates, and sulfate esters; cationic hydrophilic groups such as amine salts and quaternary ammonium salts; amphoteric hydrophilic groups such as betaine; and nonionic hydrophilic groups such as polyoxyalkylenes. 【0072】 In one embodiment of the present invention, monomer (C) preferably has a polyoxyalkylene structure from the viewpoint of versatility. Examples of such monomers include polyoxyethylene and polyoxypropylene. Monomer (C) preferably has a polyoxyalkylene structure having 1 to 100 repeating oxyalkylene units, more preferably has a polyoxyalkylene structure having 2 to 50 units, and even more preferably has a polyoxyalkylene structure having 5 to 20 units. 【0073】 The monomer (C) is not particularly limited as long as it is included in the above definition, but for example, Adekaria Soap SR-05, SR-10, SR-20, SR-1025, SR-2025, SR-3025, SR-10S, NE-10, NE-20, NE-30, NE-40, SE-10, SE-20, ER-10, ER-20, ER-30, ER-40 manufactured by ADEKA Corporation, and Antox-MS-60, RMA-1120, RMA-564, RMA-568, RMA-506, MA-30, MA- 50, MA-100, MA-150, RMA-1120, MPG130-MA, MPG-130MA, RMA-150M, RMA-300M, RMA-450M, RA-1020, RA-1820, Aqualon KH-05, KH-10, RN-20, RN-30, RN-50, RN-2025, HS-10, HS-20, HS-1025, BC05, BC10, BC0515, BC1025 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Eleminor JS-2, JS-20, RS-30 (manufactured by Sanyo Chemical Industries, Ltd.), Latemul (manufactured by Kao Corporation) S-180, S-180A, PD-104, PD-420, PD-430, Blenmar PE-90, PE-200, PE-350, AE-90, AE-200, AE-350, PP-500, PP-800, PP-1000, AP-40 manufactured by NOF Corporation 0, AP-550, AP-800, 700PEP-350B, 10PEP-550B, 55PET-400, 30PET-800, 55PET-800, 30PPT-800, 50PPT-800, 70PPT-800, PME-100, PME-200, Examples include PME-400, PME-1000, PME-4000, AME-400, 50POEP-800B, 50AOEP-800B, AEP, AET, APT, PLE, ALE, PSE, ASE, PKE, AKE, PNE, ANE, PNP, ANP, PNEP-600, Light Ester 130MA, 041MA, MTG, Light Acrylate EC-A, MTG-A, 130A, DPM-A, P-200A, NP-4EA, NP-8EA, EHDG-A from Kyoeisha Chemical Co., Ltd., and NK-ESTER M-20G, M-40G, M-90G, M-230G, AMP-10G, AMP-20G, AMP-60G, AM-90G, and LA from Shin Nakamura Chemical Industry Co., Ltd.From the viewpoint of versatility and micelle stability, Adekarya Soap SR-10 is preferred. 【0074】 In one embodiment of the present invention, monomer (C) may have a salt structure consisting of an acid and a base. The salt structure may be, for example, a neutral salt structure of a strong acid and a strong base, a neutral salt structure of a strong acid and a weak base, a neutral salt structure of a weak acid and a strong base, or a neutral salt structure of a weak acid and a weak base. More specific salt structures include, for example, sodium sulfonate, potassium sulfonate, calcium sulfonate, sodium nitrate, potassium nitrate, calcium nitrate, etc. (neutral salt structure of a strong acid and a strong base), ammonium sulfonate, ammonium nitrate, etc. (neutral salt structure of a strong acid and a weak base), sodium acetate, potassium acetate, calcium acetate, sodium phosphate, potassium phosphate, calcium phosphate, etc. (neutral salt structure of a weak acid and a strong base), ammonium acetate, ammonium phosphate, etc. (neutral salt structure of a weak acid and a weak base), etc. In one embodiment of the present invention, the salt structure is preferably sodium sulfonate or ammonium sulfonate. 【0075】 In one embodiment of the present invention, the content of constituent unit (c) is, for example, 0.5% by weight or more, preferably 1% by weight or more, and more preferably 2% by weight or more, based on 100% by weight of the total amount of the polysiloxane resin. When the content of constituent unit (c) is within the above range, viscosity adjustment becomes easier when the polysiloxane resin is dissolved in an aqueous medium, and it can be suitably used as an adhesion promoter. Furthermore, the upper limit of the content of constituent unit (c) is, for example, 15% by weight or less, preferably 10% by weight or less, and more preferably 8% by weight or less. When the content of constituent unit (c) is within the above range, the water resistance of the resulting adhesion promoter is good. 【0076】 (Constituent unit (d)) The constituent unit (d) is given by the following general formula (III): R 4 n -Si-(OR 5 ) 4-n ...(III) It is a constituent unit derived from the silane compound (D) shown below. The silane compound (D) is represented by the following general formula (III): R 4 n -Si-(OR 5 ) 4-n ...(III) (In the formula, R 4 Each of these is independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group, and R 4 If there are multiple, they may be the same or different, R 5 Each of these is independently either a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and n is an integer from 0 to 3. This is a silane compound having a hydrolyzable silyl group represented by . Silane compound (D) undergoes dehydration condensation with silane compound (A) and / or (D) to form a polysiloxane. Silane compound (D) can also be described as a silane compound that does not have a radically polymerizable unsaturated group and has a hydrolyzable silyl group. In this specification, silane compound (D) may be referred to as monomer (D). The constituent unit (d) may consist of only one type of silane compound (D) represented by general formula (III), or it may consist of a combination of two or more types of silane compounds (D). 【0077】 R in general formula (III) 4 Specific examples of alkyl groups in this context include, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, amyl group, isoamyl group, hexyl group, cyclohexyl group, cyclohexylmethyl group, cyclohexylethyl group, heptyl group, isoheptyl group, n-octyl group, isooctyl group, and 2-ethylhexyl group. 【0078】 R in general formula (III) 4 Specific examples of aryl groups in this context include, for example, phenyl, naphthyl, and benzyl groups. 【0079】 R in general formula (III) 5The group is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, such as a methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, nonyl group, decyl group, etc. 【0080】 Specific compounds represented by general formula (III) include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltriisopropoxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltriisopropoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, hexyltriisopropoxysilane, octyltrimethoxysilane, octyltriethoxysilane, octyltriisopropoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriisopropoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane, diphenyldimethoxysilane, trimethylmonomethoxysilane, triphenylmonomethoxysilane, and the like. 【0081】 (Constituent unit (e)) The constituent unit (e) is derived from monomer (E) having a radically polymerizable unsaturated group, other than (A), (B), and (C) above. Monomer (E) from which constituent unit (e) is derived is directly or indirectly bonded to monomer (A) and / or (B) and / or (C) by radical polymerization, and is bonded to constituent units (a) and / or (b) and / or (c). 【0082】 The monomer (E) from which the constituent unit (e) is derived is not particularly limited as long as it is a monomer having a radically polymerizable unsaturated group other than (A), (B), and (C) above, but examples include alkyl (meth)acrylates and monomers other than alkyl (meth)acrylates as shown below. 【0083】 ≪(meth)acrylate alkyl ester≫ In one embodiment of the present invention, the alkyl (meth)acrylate is a (meth)acrylate ester having an alkyl group having 1 to 18 carbon atoms, and may be a (meth)alkyl monomer that does not contain functional groups such as hydroxyl groups or epoxy groups. In one embodiment of the present invention, the alkyl group in the alkyl (meth)acrylate may be linear or branched, or it may be a cyclic cycloalkyl group. Specific examples include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, tert-butyl (meth)acrylate, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)methacrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, isobonyl (meth)acrylate, and the like. 【0084】 <<Monomers other than alkyl methacrylates>> Examples of monomers other than alkyl (meth)acrylates include nitrile group-containing radical polymerizable monomers such as (meth)acrylonitrile; hydroxyl group-containing radical polymerizable monomers such as glycidyl (meth)acrylate; 2-hydroxypropyl (meth)acrylate; 2-hydroxypropyl (meth)acrylate; monomers having two or more polymerizable unsaturated bonds such as ethylene glycol di(meth)acrylate and allyl (meth)acrylate; fluorine-containing radical polymerizable monomers such as trifluoro(meth)acrylate, pentafluoro(meth)acrylate, perfluorocyclohexyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl methacrylate, and β-(perfluorooctyl)ethyl (meth)acrylate; and the like. 【0085】 In one embodiment of the present invention, the weight-average molecular weight of the polysiloxane resin is not particularly limited, but is, for example, 5,000 to 500,000, preferably 8,000 to 100,000, and more preferably 10,000 to 80,000. The weight-average molecular weight of the polysiloxane resin is measured using a high-speed GPC instrument HLC-8320GPC manufactured by Tosoh Corporation. 【0086】 The aqueous coating composition preferably contains 5 to 100% by weight of polysiloxane resin, more preferably 8 to 100% by weight, more preferably 20 to 100% by weight, even more preferably 40 to 100% by weight, and particularly preferably 60 to 100% by weight, based on 100% by weight of resin solids in the curable resin composition. This configuration has the advantage of providing an aqueous coating composition with excellent adhesion and weather resistance. In this specification, the resin solids in the curable resin composition refer to the resin composition excluding the solvent. 【0087】 <Water> This adhesion-improving agent contains water. The water content in this adhesion-improving agent is not particularly limited, but it may be included in a proportion of, for example, 30% to 90% by weight, preferably 35% to 80% by weight, and more preferably 40% to 70% by weight, relative to the polysiloxane resin. This configuration has the advantage of being easy to use as an adhesion-improving agent. 【0088】 <Other ingredients> This adhesion-imparting agent may contain a non-aqueous solvent, within the limits of achieving the effects of the present invention. In this specification, "non-aqueous solvent" means all solvents other than water. In this specification, "non-aqueous solvent" may be a mixed solvent containing water, and includes solvents containing water in an amount of less than 50% by weight. Non-aqueous solvents are not particularly limited as long as they satisfy the above definition, but examples include hydrocarbons such as toluene, xylene, n-hexane, and cyclohexane; acetic acid esters such as ethyl acetate and butyl acetate; cellosolves such as ethyl cellosolve and butyl cellosolve; ether esters such as cellosolve acetate; ketones such as methyl ethyl ketone, acetate acetate, acetylacetone, methyl isobutyl ketone, and acetone; alcohols such as methanol, 2-propanol, n-butanol, isobutanol, hexanol, and octanol; and film-forming aids for aqueous coatings such as 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, dipropylene glycol-n-butyl ether, and dipropylene glycol dimethyl ether. 【0089】 The adhesion-improving agent may contain additives commonly used in the art (particularly in the field of coatings) to the extent that it achieves the effects of the present invention. Examples of such additives include pigments, fillers, plasticizers, film-forming aids, wetting agents, dispersants, thickeners, defoamers, preservatives, antioxidants, anti-settling agents, leveling agents, UV absorbers, antistatic agents, antifreeze agents, antibacterial agents, antifungal and anti-algal agents, tackifiers, rust inhibitors, and hydrophilic agents. The additive may contain only one type or two or more types. The amount of these additives can be appropriately determined by those skilled in the art depending on the intended use. 【0090】 In one embodiment of the present invention, the method for producing the adhesion agent may be the method described in the example. 【0091】 (2-3. Method for producing aqueous coating compositions) A method for producing an aqueous coating composition according to one embodiment of the present invention may be a method of adding the adhesion promoter to a curable resin composition using water as a medium and mixing by mechanical stirring. 【0092】 [3. Method for manufacturing the coating layer] This manufacturing method is a method for producing a coating layer, comprising the step of applying an aqueous coating composition, which comprises a water-curable resin composition and an adhesion promoter, to a substrate, wherein the adhesion promoter contains a polysiloxane resin (A) and water, and the polysiloxane resin (A) has a polymer containing constituent units derived from monomers having radical polymerizable groups, and the monomers include (i) monomers having a salt structure consisting of an acid and a base, being soluble in water and not forming micelles in water, and (ii) monomers capable of forming micelles in water. 【0093】 This manufacturing method, having the above configuration, can provide a coating layer made of a water-based coating composition that has excellent adhesion and weather resistance. The coating layer according to one embodiment of the present invention may be referred to as "this coating layer." 【0094】 This manufacturing method includes a method of application using this aqueous coating composition. 【0095】 In this manufacturing method, from the viewpoint of versatility, (ii) the monomer capable of forming micelles in water is preferably a monomer having a polyoxyalkylene structure. 【0096】 In this manufacturing method, the curable resin composition preferably contains one or more selected from the group consisting of acrylic silicone resin emulsion, acrylic resin emulsion, styrene acrylic resin emulsion, acrylic urethane resin emulsion, vinyl acetate resin emulsion, and fluororesin emulsion. This configuration has the advantage of having good workability. 【0097】 In this manufacturing method, the curable resin composition is preferably an acrylic silicone resin emulsion from the viewpoint of weather resistance and other factors. 【0098】 In this manufacturing method, the curable resin composition preferably contains constituent units derived from a radically polymerizable unsaturated monomer (x) and constituent units derived from a radically polymerizable unsaturated monomer (y) having a hydrolyzable silyl group. This configuration has the advantage that the resulting aqueous coating composition has high weather resistance. In this manufacturing method, the content of constituent units derived from the radically polymerizable unsaturated monomer (y) in the curable resin composition is preferably 0.1 to 20% by weight based on 100% by weight of the curable resin composition. This configuration has the advantage that the resulting aqueous coating composition has excellent weather resistance and is suitable for storage. 【0099】 In this manufacturing method, the aqueous coating composition preferably contains 5 to 100% by weight of the polysiloxane resin relative to 100% by weight of the resin solids content in the curable resin composition. This configuration has the advantage of providing an aqueous coating composition with excellent adhesion and weather resistance. 【0100】 In this manufacturing method, the polysiloxane resin comprises a constituent unit (a) derived from a silane compound (A) having a radically polymerizable unsaturated group and a hydrolyzable silyl group; a constituent unit (b) derived from a monomer (B) having a salt structure consisting of an acid and a base and a radically polymerizable group, but lacking a hydrolyzable silyl group, being soluble in water, and not forming micelles in water; a constituent unit (c) derived from a monomer (C) having a polyoxyalkylene structure and a radically polymerizable group, lacking a hydrolyzable silyl group, and capable of forming micelles in water; and optionally, a monomer other than (A), (B), and (C) of the following general formula (III): R 4 n -Si-(OR 5 ) 4-n ...(III) (In the formula, R 4Each of these is independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group, and R 4 If there are multiple, they may be the same or different, R 5 Each of these is independently either a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and n is an integer from 0 to 3. It is preferable to include a constituent unit (d) derived from a silane compound (D) represented by . This configuration has the advantage of providing a water-based coating composition with excellent adhesion to the substrate and weather resistance. 【0101】 In this manufacturing method, it is preferable that the polysiloxane resin contained in the aqueous coating composition further contains constituent units (e) derived from a monomer (E) having a radical polymerizable group, other than (A), (B), and (C) above. With this configuration, the polysiloxane resin can be made elastic. 【0102】 In this manufacturing method, the polysiloxane resin contained in the aqueous coating composition preferably contains 1 to 20% by weight of the constituent unit (b) and 1 to 10% by weight of the constituent unit (c) based on 100% by weight of the total amount of the polysiloxane resin. This configuration has the advantage of easily achieving both the compatibility of the polysiloxane resin with water and the water resistance of the adhesion imparter. 【0103】 In the aforementioned manufacturing method, it is preferable that the polysiloxane resin contained in the aqueous coating composition contains at least 10% by weight of the constituent units (a) and (d) in total, relative to 100% by weight of the total amount of the polysiloxane resin. This configuration has the advantage of easily achieving both the viscosity of the polysiloxane resin and the water resistance of the adhesion imparter. 【0104】 This manufacturing method includes a step of applying the aqueous coating composition described in section [2. Aqueous Coating Composition] to a substrate described later. Alternatively, this manufacturing method can also be said to include a step of applying the aqueous coating composition obtained by the manufacturing method described in section (2-3. Method for Manufacturing Aqueous Coating Composition) to a substrate described later. 【0105】 In one embodiment of the present invention, the substrate is not particularly limited and may be either an organic or inorganic substrate, and may be coated. Specifically, the substrate can be metal (e.g., aluminum, stainless steel), glass, porcelain, tile, stone, wood, resin molded product, mortar, slate, ABS, acrylic, PVC-coated steel sheet, polycarbonate, galvalume steel sheet (registered trademark), electrodeposited coated sheet, cold-rolled steel sheet, calcium silicate board, etc. The coating applied to the substrate may be acrylic paint, acrylic urethane paint, acrylic silicone paint, fluoropolymer paint, etc. 【0106】 In one embodiment of the present invention, the method for forming the coating layer is not particularly limited, but for example, it is a method of applying and curing the aqueous coating composition. The method will be described in detail below. 【0107】 The method of applying this aqueous coating composition is not particularly limited. For example, it may be applied using brushes, rollers, air sprays, airless sprays, etc., commonly used in general painting. It can also be applied using methods such as reverse coating, gravure coating, bar coating, die coating, spray coating, kiss coating, wire bar coating, and curtain coating. 【0108】 As described above, this coating layer can also be described as a coating layer obtained by applying and curing this aqueous coating composition. 【0109】 Any known method can be used to cure this coating layer. 【0110】 In other words, one aspect of the present invention includes the following: [1] A water-based coating composition comprising a water-based curable resin composition and an adhesion promoter, The adhesion agent contains a polysiloxane resin and water. The polysiloxane-based resin has a polymer containing constituent units derived from monomers having radical polymerizable groups, The monomer is (i) A monomer having a salt structure consisting of an acid and a base, soluble in water, and not forming micelles in water, (ii) A water-based coating composition comprising monomers capable of forming micelles in water. [2] The aqueous coating composition according to [1], wherein the monomer capable of forming micelles in water is a monomer having a polyoxyalkylene structure. [3] The aqueous coating composition according to [1] or [2], wherein the curable resin composition comprises one or more selected from the group consisting of acrylic silicone resin emulsion, acrylic resin emulsion, styrene acrylic resin emulsion, acrylic urethane resin emulsion, vinyl acetate resin emulsion, and fluororesin emulsion. [4] The water-based coating composition according to any one of [1] to [3], wherein the curable resin composition is an acrylic silicone resin emulsion. [5] The curable resin composition comprises constituent units derived from a radical polymerizable unsaturated monomer (x), and It contains constituent units derived from a radical polymerizable unsaturated monomer (y) having a hydrolyzable silyl group, The aqueous coating composition according to any one of [1] to [4], wherein the content of the constituent units derived from the radical polymerizable unsaturated monomer (y) is 0.1 to 20% by weight based on 100% by weight of the curable resin composition. [6] The aqueous coating composition is With respect to 100% by weight of the resin solids content in the curable resin composition, A water-based coating composition according to any one of [1] to [5], comprising 5 to 100% by weight of the polysiloxane resin. [7] The polysiloxane resin comprises a constituent unit (a) derived from a silane compound (A) having a radically polymerizable unsaturated group and a hydrolyzable silyl group, A constituent unit (b) derived from monomer (B) having a salt structure consisting of an acid and a base and a radical polymerizable group, but lacking a hydrolyzable silyl group, being soluble in water, and not forming micelles in water, A constituent unit (c) derived from a monomer (C) having a polyoxyalkylene structure and radical polymerizable groups, but lacking hydrolyzable silyl groups, and capable of forming micelles in water, Optionally, the following general formula (III), other than (A), (B), and (C): R 4 n -Si-(OR 5 ) 4-n ...(III) (In the formula, R 4 Each of these is independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group, and R 4 If there are multiple, they may be the same or different, R 5 Each of these is independently either a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and n is an integer from 0 to 3. A constituent unit (d) derived from the silane compound (D) shown, A water-based coating composition according to any one of [1] to [6], comprising: [8] The aqueous coating composition according to [7], further comprising a constituent unit (e) derived from a monomer (E) having a radical polymerizable group, other than (A), (B), and (C). [9] The aqueous coating composition according to [7] or [8], comprising 1 to 20% by weight of the constituent unit (b) and 1 to 10% by weight of the constituent unit (c) based on 100% by weight of the total amount of the polysiloxane resin.

[10] The aqueous coating composition according to any one of [7] to [9], comprising 10% by weight or more of the constituent units (a) and (d) in total, based on 100% by weight of the total amount of the polysiloxane resin.

[11] A method for producing a coating layer, comprising the step of applying an aqueous coating composition, which contains a water-curable resin composition and an adhesion promoter, to a substrate, The aforementioned adhesion-improving agent is It contains a polysiloxane resin (A) and water. The polysiloxane resin (A) has a polymer containing constituent units derived from monomers having radical polymerizable groups, The monomer is (i) a monomer having a salt structure consisting of an acid and a base, soluble in water, and not forming micelles in water, and (ii) A method for producing a coating layer comprising monomers capable of forming micelles in water. [Examples] 【0111】 The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. 【0112】 〔material〕 <Adhesion-enhancing agent> (Monomer (A)) γ-(meth)acryloxypropyltrimethoxysilane (abbreviated as "TSMA"): "A-174" manufactured by Momentive Performance Materials Japan LLC. (Monomer (B)) Acrylamide-t-butylsulfonate sodium (abbreviated as "ATBS-Na"): "ATBS-Na" manufactured by Toagosei Co., Ltd. (Monomer (C)) Ether sulfate type ammonium salt (abbreviated as "SR-10"): "Adekaria Soap SR-10" manufactured by ADEKA Corporation, commercially classified as "reactive anionic emulsifier", compound represented by the following formula (A): 【0113】 [ka] 【0114】 (Monomer (D)) Methyltrimethoxysilane (abbreviated as "M-TMS"): "Z-6033" manufactured by Dow Toray Industries, Inc. Phenyltrimethoxysilane (abbreviated as "Ph-TMS"): "Z-6124" manufactured by Dow Toray Industries, Inc. (Monomer (E)) Methyl methacrylate (abbreviated as "MMA"): Manufactured by Mitsubishi Gas Chemical Company, Inc. Butyl acrylate (abbreviated as "BA"): Manufactured by Nippon Shokubai Co., Ltd. (others) pure water Lithium chloride: "LiCl" manufactured by Tokyo Chemical Industry Co., Ltd. 2-Propanol: Manufactured by Nacalai Tesque Co., Ltd. Radical polymerization initiator: 2,2'-Azobis(2,4-dimethylvaleronitrile): Manufactured by Tokyo Chemical Industry Co., Ltd. (Antifoaming agent) Acrylic defoaming agent: "Agitan295" manufactured by MUNZING CHEMIE. (Film-forming aid) 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate: "CS-12" manufactured by JNC Corporation (Thickening agent) Sunopco's "SN Thickener 612NC" <Curable resin composition> The materials used will be described later in [Synthesis Example 4] to [Synthesis Example 6]. 【0115】 <Base material> ABS manufactured by TP Giken Co., Ltd. Acrylic manufactured by TP Giken Co., Ltd. Aluminum (anodized) manufactured by TP Giken Co., Ltd. Glass manufactured by TP Giken Co., Ltd. PVC-coated steel sheets manufactured by Taisuke Kikai Co., Ltd. Polycarbonate manufactured by TP Giken Co., Ltd. Galvalume steel sheet (registered trademark) manufactured by TP Giken Co., Ltd. SUS(304) manufactured by TP Giken Co., Ltd. Cold-rolled steel sheet manufactured by TP Giken Co., Ltd. Calcium silicate board manufactured by TP Giken Co., Ltd. [Measurement and evaluation methods] Measurements and evaluations in the examples and comparative examples were performed using the following methods. 【0116】 (Adhesion test) Apply 100g / m² to the substrate. 2 After applying the aqueous coating composition, it was cured for one week in a constant temperature room at 23°C and 50% relative humidity. On the surface of the resulting coating layer, six straight lines were drawn vertically and horizontally at 1 mm intervals using a utility knife, creating a grid of 25 squares. The cuts were made to a depth that reached the substrate. Then, cellophane tape (registered trademark, manufactured by Nichiban Co., Ltd.) was firmly pressed onto the grid area, and the end of the cellophane tape (registered trademark) was peeled off in one swift motion at a 45-degree angle to evaluate the condition of the grid. In Table 4, the total number of squares (25) is shown in the denominator, and the number of squares that remained without the coating layer peeling off is shown in the numerator. 【0117】 In this embodiment, if the adhesion test results obtained by the method described above are 20 / 25 or higher, the water-based coating composition can be considered to have excellent adhesion to the relevant substrate. Therefore, in the adhesion test results obtained by the method described above, if three or more of the ten substrates shown in Table 4 show a result of 20 / 25 or higher, it was determined that "the water-based coating composition has excellent adhesion." In this embodiment, the adhesion test results obtained by the method described above are preferably 20 / 25 or higher, more preferably 22 / 25 or higher, and even more preferably 25 / 25. Furthermore, in this embodiment, the number of substrates showing a result of 20 / 25 or higher in the adhesion test results obtained by the method described above is preferably three or more, more preferably four or more, more preferably five or more, more preferably six or more, even more preferably seven or more, and particularly preferably eight or more, out of the ten substrates shown in Table 4. 【0118】 (Weather resistance test) Weather resistance was evaluated by referring to International Publication No. 2016 / 052636 and Japanese Patent Publication No. 5555449. 【0119】 In short, accelerated weathering tests were conducted on coating layers on test specimens prepared using the method described below, employing a metal halide lamp type testing machine [Daipla Wintes Co., Ltd., model KU-R5CI-A]. The 60° gloss value of the coating layer was measured approximately 400 hours into the accelerated weathering test, and the gloss retention rate was calculated. A higher gloss retention rate indicates better weather resistance. The test conditions for the accelerated weathering test were as follows: Illuminance: 85mW / cm 2 Irradiation: 63℃ 50% 6 hours Condensation: 30℃ 98% 2 hours Shower: 30 seconds before and after condensation. 【0120】 In this embodiment, if the result of the weather resistance test of the coating layer performed by the method described above was a gloss retention rate of 65% or more, it was determined that "the water-based coating composition has excellent weather resistance." In this embodiment, the gloss retention rate of the coating layer is preferably 65% ​​or more, more preferably 67% or more, even more preferably 70% or more, and particularly preferably 75% or more. 【0121】 [Synthesis Example 1] (Preparation of the co-condensate (main chain, silane monomer)) In a reactor equipped with a stirrer, thermometer, and reflux condenser, 3.0 parts by weight of TSMA, 46.4 parts by weight of M-TMS, 16.2 parts by weight of Ph-TMS, 16.4 parts by weight of pure water, and 0.018 parts by weight of LiCl were charged and reacted at a reaction temperature of 105°C for 3 hours with stirring to obtain a cocondensate. 【0122】 (Preparation of graft cocondensates (polymerization of side chains (graft monomers))) In a reactor equipped with a stirrer, thermometer, reflux condenser, nitrogen gas inlet tube, and dropping funnel, 10 parts by weight of pure water and 15 parts by weight of 2-propanol were charged. After raising the temperature to 75°C while introducing nitrogen gas, a mixed solution of the aforementioned cocondensate, 2.5 parts by weight of ATBS-Na, 5 parts by weight of SR-10, 26.25 parts by weight of MMA, 26.25 parts by weight of BA, 1.2 parts by weight of 2,2-azobis(2,4-dimethylvaleronitrile), 10 parts by weight of pure water, and 10 parts by weight of 2-propanol was added dropwise from the dropping funnel at a constant rate over 5 hours. Next, a mixed solution of 0.12 parts by weight of 2,2-azobis(2,4-dimethylvaleronitrile) and 5 parts by weight of 2-propanol was added dropwise at a constant rate over 1 hour. Subsequently, the mixture was stirred at 75°C for 2 hours, and then degassed using a rotary evaporator until the non-volatile components amounted to 90% or more. Next, the mixture was diluted with water until the non-volatile components amounted to 50%. After cooling to room temperature, a composition containing polysiloxane resin and water was obtained. Table 1 shows the amount of each monomer used in the obtained composition. In Table 1, the unit for each component amount is "parts by weight". Table 2 shows the content of each constituent unit in the polysiloxane resin (the amount used shown in Table 1 minus the weight of the generated volatile components). In Table 2, the unit for each component amount is also "parts by weight". 【0123】 [Synthesis Example 2] A composition containing a polysiloxane resin and water was obtained by the same method as in Synthesis Example 1, except that the amount of each monomer used was changed to the amount shown in Table 1. 【0124】 [Synthesis Example 3] A composition containing polysiloxane resin and water was obtained by the same method as in Synthesis Example 1, except that the amount of each monomer used was changed to the amount shown in Table 1, and the amount of pure water used in (preparation of the co-condensate (main chain, silane monomer)) was 20.5 parts by weight and LiCl was 0.023 parts by weight. 【0125】 [Table 1] 【0126】 [Table 2] 【0127】 [Synthesis Example 4] In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen gas inlet tube, and dropping funnel, 160 parts by weight of deionized water, 1.4 parts by weight of Newcol-707SF (manufactured by Nippon Emulsifier Co., Ltd.), and 1.0 part by weight of a 5% sodium bicarbonate aqueous solution were charged, and the temperature was raised to 50°C while introducing nitrogen gas. After heating, 2.0 parts by weight of a 7% t-butyl hydroperoxide aqueous solution, 1.1 parts by weight of a 20% Bruggolite FF-6 aqueous solution, and 1.4 parts of a mixed aqueous solution of ferrous sulfate heptahydrate (0.10 ethylenediaminetetraacetate disodium (0.40%)) were added. Next, 200 parts by weight of a monomer mixture containing 54.2 parts by weight of 2-ethylhexyl acrylate, 142.0 parts by weight of isobutyl methacrylate, and 3.8 parts by weight of γ-methacryloxypropyl methyldimethoxysilane were added to 12 parts by weight of Adekarya Soap SR-105 (manufactured by ADEKA Corporation: active ingredient 25%), 1.9 parts by weight of Adekarya Soap ER-2 (manufactured by ADEKA Corporation: active ingredient 75%), and 71 parts by weight of deionized water to emulsify the monomer emulsion, which was added at a constant rate over 200 minutes. During this time, 2.2 parts by weight of a 7% t-butyl hydroperoxide aqueous solution and 2.5% Bruggolite 1.8 parts by weight of FF aqueous solution was added in three separate additions. Polymerization was carried out 1 hour after the addition of the monomer emulsion was complete. Furthermore, 0.6 parts by weight of 7% t-butyl hydroperoxide aqueous solution, 2.2 parts by weight of 2.Bruggolite FF aqueous solution, and 1.4 parts of a mixed aqueous solution of ferrous sulfate heptahydrate (0.0%) / ethylenediaminetetraacetate disodium (0.40%) were added. Subsequently, 200 parts by weight of a monomer mixture containing 20.0 parts by weight of butyl methacrylate, 165.0 parts by weight of butyl methacrylate, 2.0 parts by weight of γ-methacryloxypropyltriethoxysilane, 12.0 parts by weight of methacrylate 100 (hydrophilic vinyl monomer containing polyoxyethylene chain (10 repeating units) (manufactured by Nippon Emulsifier Co., Ltd.)), and 1.0 part by weight of n-dodecyl mercaptan was added, along with 12 parts by weight of Adekarya soap SR-1025 and Adekarya soap ER-20. A monomer emulsion, prepared by adding 1.9 parts by weight and 71 parts by weight of deionized water, was added at a constant rate over 200 minutes. During this time, 2.4 parts by weight of a 7% t-butyl hydroperoxide aqueous solution and 3.4 parts by weight of a 2.5% Brgolite FF-6 aqueous solution were added in four separate additions.Polymerization was carried out 1.5 hours after the addition of the monomer emulsion was completed. 22 parts of a 5% sodium bicarbonate aqueous solution were added to the resulting synthetic resin emulsion, and then the solid content was adjusted to 50% with deionized water. Since the parts by weight of the radically polymerizable monomer and the parts by weight of the constituent units were almost the same, the amount of monomer used and the content of the constituent units were considered to be the same. 【0128】 [Synthesis Example 5] In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen gas inlet tube, and dropping funnel, 360 parts by weight of deionized water, 259.2 parts by weight of active ingredient in Adekarya Soap SR-1025 (manufactured by ADEKA Corporation), and 1.0 part by weight of 5% sodium bicarbonate aqueous solution were charged, and the temperature was raised to 50°C while introducing nitrogen gas. After raising the temperature, 20 parts by weight of a monomer mixture containing 7.4 parts by weight of 2-ethylhexyl acrylate, 10.6 parts by weight of butyl methacrylate, and 2.0 parts by weight of γ-methacryloxypropylmethyldimethoxysilane, 2.0 parts by weight of 7% t-butyl hydroperoxide aqueous solution, 2 parts of ferrous sulfate heptahydrate (0.10%) / ethylenediaminetetraacetate disodium (0.40%) mixed aqueous solution, and 1.4 parts by weight of 10% Bruggolite FF-6 aqueous solution were added, and polymerization was carried out for 30 minutes. 【0129】 Furthermore, 1.0 part by weight of a 7% t-butyl hydroperoxide aqueous solution and 2.8 parts by weight of a 2.5% Brgolite FF- aqueous solution were added. Subsequently, 380 parts by weight of a monomer mixture containing 80.9 parts by weight of methyl methacrylate, 228.4 parts by weight of butyl methacrylate, 4.1 parts by weight of isobutyl methacrylate, 33.7 parts by weight of 2-ethylhexyl acrylate, 11.4 parts by weight of γ-methacryloxypropyltriethoxysilane, 20.0 parts by weight of Bremmer PE-200 (a hydrophilic vinyl monomer containing polyoxyethylene chains (4.5 repeating units) (manufactured by NOF Corporation)), and 1.6 parts by weight of γ-mercaptopropyltriethoxysilane was added at a constant rate over 380 minutes. This monomer emulsion was then emulsified by adding 34.2 parts by weight of Adekarya soap SR-1025, 11.4 parts by weight of Adekarya soap ER-20, and 151 parts by weight of deionized water to the monomer mixture. During this time, 3.1 parts by weight of a 7% t-butyl hydroperoxide aqueous solution and 5.4 parts by weight of a 2.5% Bruggolite FF-6 aqueous solution were added in five separate additions. Polymerization was carried out 1.5 hours after the addition of the monomer emulsion was completed. After adding 28 parts of a 5% sodium bicarbonate aqueous solution to the obtained synthetic resin emulsion, the solid content was adjusted to 40% with deionized water. Since the parts by weight of the radically polymerizable monomer and the parts by weight of the constituent units are almost the same, the amount of monomer used and the content of the constituent units were considered to be the same. 【0130】 [Synthesis Example 6] In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen gas inlet tube, and dropping funnel, 152 parts by weight of deionized water, 0.4 parts by weight of Adekarya Soap SR-1025 (manufactured by ADEKA Corporation: 25% active ingredient), and 1.0 part by weight of 5% sodium bicarbonate aqueous solution were charged, and the temperature was raised to 50°C while introducing nitrogen gas. After raising the temperature, 2.0 parts by weight of 7% t-butyl hydroperoxide aqueous solution, 2.8 parts of ferrous sulfate heptahydrate (0.10%) / ethylenediaminetetraacetate disodium (0.40%) mixed aqueous solution, and 1.4 parts by weight of 10% Bruggolite FF-6 aqueous solution were added. Next, to a monomer mixture containing 68.0 parts by weight of butyl methacrylate, 40.0 parts by weight of butyl acrylate, 49.0 parts by weight of styrene, and 3.0 parts by weight of γ-methacryloxypropylmethyldimethoxysilane, 9.0 parts by weight of Adekarya Soap SR-1025 (manufactured by ADEKA Corporation: 25% active ingredient), 1.6 parts by weight of Adekarya Soap ER-20 (manufactured by ADEKA Corporation: 75% active ingredient), and 57 parts by weight of deionized water were added to obtain a monomer emulsion, which was then added at a constant rate over 160 minutes. During this time, 1.2 parts by weight of a 7% t-butyl hydroperoxide aqueous solution and 2.4 parts by weight of a 2.5% Brulite FF-6 aqueous solution were added in two separate additions. Polymerization was carried out 2 hours after the completion of the monomer emulsion addition. During this time, 1.2 parts by weight of a 7% t-butyl hydroperoxide aqueous solution and 1.8 parts by weight of a 2.5% Bruggolite FF-6 aqueous solution were added in three separate additions. 【0131】 Furthermore, 1.2 parts by weight of a 7% t-butyl hydroperoxide aqueous solution and 3.2 parts by weight of a 2.5% Brgolite FF-6 aqueous solution were added. Subsequently, a monomer mixture and chain transfer agent mixture containing 56.0 parts by weight of methyl methacrylate, 146.0 parts by weight of butyl methacrylate, 8.0 parts by weight of butyl acrylate, 4.0 parts by weight of γ-methacryloxypropyltriethoxysilane, 6.4 parts by weight of 2-hydroxyethyl methacrylate, 6.4 parts by weight of glycidyl methacrylate, Bremmer PE-350 (a hydrophilic vinyl monomer containing polyoxyethylene chains (8 repeating units) (manufactured by NOF Corporation)), and 1.2 parts by weight of n-dodecyl mercaptan was emulsified by adding 14 parts by weight of Adekarya Soap SR-1025 (manufactured by ADA Corporation: 25% active ingredient), 2.4 parts by weight of Adekarya Soap ER-20 (manufactured by ADE Corporation: 75% active ingredient), and 86 parts by weight of deionized water, and this monomer emulsion was added at a constant rate over 240 minutes. During this time, 2.0 parts by weight of a 7% t-butyl hydroperoxide aqueous solution and 3.2 parts by weight of a 2.5% Bruggolite FF-6 aqueous solution were added in two separate additions. Polymerization was carried out 1.5 hours after the additions were completed. During this time, 0.8 parts by weight of a 7% t-butyl hydroperoxide aqueous solution and 1.2 parts by weight of a 2.5% Bruggolite FF-6 aqueous solution were added in two separate additions. After adding 24 parts of a 5% sodium bicarbonate aqueous solution to the resulting emulsion, the solid content was adjusted to 50% with deionized water. Since the parts by weight of the radically polymerizable monomer and the parts by weight of the constituent units are almost the same, the amount of monomer used and the content of the constituent units were considered to be the same. 【0132】 [Formulation examples 1-3] Adhesion-improving agents were prepared by combining the components of the compositions obtained in Synthesis Examples 1-3 according to the formulations shown in Table 3. In Table 3, the unit of each component amount is "parts by weight". 【0133】 [Formulation examples 4-6] Using the compositions obtained in Synthesis Examples 4-6, curable resin compositions were prepared by blending each component according to the formulations shown in Table 3. In Table 3, the unit of each component amount is "parts by weight". 【0134】 [Table 3] 【0135】 [Examples 1-9, Comparative Examples 1-3] (Preparation of aqueous coating compositions) Using the adhesion-improving agents obtained in formulation examples 1-3 and the curable resin compositions obtained in formulation examples 4-6, water-based coating compositions were prepared by blending each component according to the formulations shown in Table 4. In Table 4, the unit of each component amount is "parts by weight". 【0136】 (Fabrication of the coating layer) On each substrate shown in Table 4, the coating amount is 100 g / m². 2 To achieve this result, the water-based coating composition was applied and then cured for one week in a constant temperature room at 23°C and 50% relative humidity. 【0137】 [Table 4] 【0138】 Table 4 shows that the adhesion to the substrate is improved by including adhesion promoters (Formulation Examples 1-3) in the water-based coating compositions (Formulation Examples 4-5). Furthermore, it was shown that the adhesion to the substrate improves as the content of adhesion promoters in the water-based coating composition increases. 【0139】 As shown in Table 1, the composition obtained in Synthesis Example 3 has a higher content of inorganic component constituent units (constituent units derived from the -Si-O-Si- structure) compared to the compositions obtained in Synthesis Examples 1 and 2. Furthermore, the results in Table 4 show that the adhesion promoter obtained in Synthesis Example 3, which has a higher content of inorganic component constituent units, exhibits superior adhesion to the substrate. From this, it can be inferred that the amount of inorganic component constituent units in a water-based coating composition contributes to its adhesion to the substrate. [Industrial applicability] 【0140】 This water-based coating composition is suitably used, for example, as a coating composition for interior and exterior building applications, automotive applications such as metallic bases or clear coatings on metallic bases, direct coating of metals such as aluminum, stainless steel, and silver, direct coating of ceramic materials such as slate, concrete, roof tiles, mortar, gypsum board, asbestos slate, asbestos board, precast concrete, lightweight aerated concrete, calcium silicate board, tiles, and bricks, as well as for glass and stone materials such as natural marble and granite.

Claims

[Claim 1] A water-based coating composition comprising a water-based curable resin composition and an adhesion promoter, The adhesion agent contains a polysiloxane resin and water. The aforementioned polysiloxane-based resin is A constituent unit (a) derived from a silane compound (A) having a radically polymerizable unsaturated group and a hydrolyzable silyl group, A constituent unit (b) derived from monomer (B) having a salt structure consisting of an acid and a base and a radical polymerizable group, but lacking a hydrolyzable silyl group, being soluble in water, and not forming micelles in water, A constituent unit (c) derived from a monomer (C) having a polyoxyalkylene structure and radical polymerizable groups, but lacking hydrolyzable silyl groups, and capable of forming micelles in water, Other than (A), (B), and (C) above, the following general formula (III): R 4 n -Si- (OR 5 ) 4-n...(III) (In the formula, each R4 is independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group, and if there are multiple R4s, they may be the same or different; each R5 is independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; and n is an integer from 0 to 3.) A constituent unit (d) derived from the silane compound (D) shown, Includes, A water-based coating composition in which, in the polysiloxane resin, the constituent unit (a) and the constituent unit (d) form a main chain, and the constituent unit (b) and the constituent unit (c) form a side chain. [Claim 2] The aqueous coating composition according to claim 1, wherein the curable resin composition comprises one or more selected from the group consisting of acrylic silicone resin emulsion, acrylic resin emulsion, styrene acrylic resin emulsion, acrylic urethane resin emulsion, vinyl acetate resin emulsion, and fluororesin emulsion. [Claim 3] The aqueous coating composition according to claim 1, wherein the curable resin composition is an acrylic silicone resin emulsion. [Claim 4] The curable resin composition comprises a constituent unit derived from a radically polymerizable unsaturated monomer (x), and It contains constituent units derived from a radical polymerizable unsaturated monomer (y) having a hydrolyzable silyl group, The aqueous coating composition according to claim 1, wherein the content of the constituent units derived from the radical polymerizable unsaturated monomer (y) is 0.1 to 20% by weight with respect to 100% by weight of the curable resin composition. [Claim 5] The aqueous coating composition, With respect to 100% by weight of the resin solids content in the curable resin composition, The aqueous coating composition according to claim 1, comprising 5 to 100% by weight of the polysiloxane resin. [Claim 6] The aqueous coating composition according to claim 1, further comprising a constituent unit (e) derived from a monomer (E) having a radical polymerizable group, other than (A), (B), and (C) mentioned above. [Claim 7] The aqueous coating composition according to claim 1, comprising 1 to 20% by weight of the constituent unit (b) and 1 to 10% by weight of the constituent unit (c) based on 100% by weight of the total amount of the polysiloxane resin. [Claim 8] The aqueous coating composition according to claim 1, comprising 10% by weight or more of the constituent units (a) and (d) in total, based on 100% by weight of the total amount of the polysiloxane resin. [Claim 9] A method for producing a coating layer, comprising the step of applying an aqueous coating composition, which contains a water-curable resin composition and an adhesion promoter, to a substrate, The aforementioned adhesion-improving agent is It contains a polysiloxane-based resin (A) and water. The aforementioned polysiloxane-based resin is A constituent unit (a) derived from a silane compound (A) having a radically polymerizable unsaturated group and a hydrolyzable silyl group, A constituent unit (b) derived from monomer (B) having a salt structure consisting of an acid and a base and a radical polymerizable group, but lacking a hydrolyzable silyl group, being soluble in water, and not forming micelles in water, A constituent unit (c) derived from a monomer (C) having a polyoxyalkylene structure and radical polymerizable groups, but lacking hydrolyzable silyl groups, and capable of forming micelles in water, Other than (A), (B), and (C) above, the following general formula (III): R 4 n -Si- (OR 5 ) 4-n...(III) (In the formula, each R4 is independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group, and if there are multiple R4s, they may be the same or different; each R5 is independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; and n is an integer from 0 to 3.) A constituent unit (d) derived from the silane compound (D) shown, Includes, A method for manufacturing a coating layer, wherein in the polysiloxane resin, the constituent unit (a) and the constituent unit (d) form a main chain, and the constituent unit (b) and the constituent unit (c) form a side chain.

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