Paint composition, paint film, and method for repairing or reinforcing concrete structures and method for preventing peeling

Abstract

To provide a coating composition excellent in curability at low temperatures, and capable of forming a coated film excellent in performance such as visibility, fire retardancy, crack followability, peeling prevention, and adhesion.SOLUTION: A coating composition according to the present invention comprises a curable resin (A) and a silane coupling agent (B). The curable resin (A) includes a hydrolyzable alkoxysilyl group represented by the following general formula (1): -X-CH2-SiR1Y (OR2)3-Y (1) (where, X represents a binding functional group in which a heteroatom having a lone electron pair binds to a methylene group binding to a silicon atom contained in the hydrolyzable silyl group, R1 and R2 each independently represent a C1 to C10 hydrocarbon group, Y represents 0, 1 or 2), and the silane coupling agent (B) contains an amino-silane compound.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a coating composition. The present invention also relates to a coating film formed from the coating composition. Furthermore, the present invention also relates to a method for repairing or reinforcing a concrete structure using the coating composition, and a method for preventing spalling of a concrete structure. [Background technology]

[0002] Traditionally, concrete structures have been subject to deterioration due to various factors, resulting in cracks and spalling of concrete pieces. Therefore, a simple method to prevent spalling of concrete, which has a significant impact on third parties, is needed. One simple method for preventing spalling of concrete is to apply a coating to the surface of the concrete structure. This anti-spadding coating must be flexible enough to conform to cracks in the concrete, tough enough to prevent the concrete pieces from falling, and adhere well to the concrete. Furthermore, highly transparent coatings are required, as they allow the deterioration of the concrete substrate to be visually observed, simplifying inspection and maintenance. Furthermore, depending on the area in which the coating is used (such as airtight areas like tunnels), flame retardancy may be required for safety reasons.

[0003] In order to solve these conventional problems, Patent Document 1 proposes the use of a clear coating composition characterized by containing at least one epoxy resin (A) selected from the group consisting of alicyclic epoxy resins (a1), bisphenol A epoxy resins (a2), bisphenol F epoxy resins (a3), and novolac epoxy resins (a4), a bifunctional or higher epoxy resin (B) excluding the epoxy resin (A), a terminally reactive butadiene-acrylonitrile copolymer (C), a polyamidoamine (D), organic fibers (E), and glass flakes (F). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-006868 Summary of the Invention [Problem to be solved by the invention]

[0005] However, since the coating composition containing the epoxy resin described in Patent Document 1 has poor curing properties at low temperatures, further improvement in curing properties at low temperatures is required. Also, further improvement in visibility is required to more easily check the state of deterioration in environments with poor visibility such as inside tunnels.

[0006] The present invention has been made in view of the above-mentioned background art and problems, and an object of the present invention is to provide a coating composition that has excellent low-temperature curing properties and is capable of forming a coating film that has excellent performance in terms of visibility, flame retardancy, crack followability, peeling resistance, adhesion, etc. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above problems and have found that the above problems can be solved by using a curable resin (A) having a specific hydrolyzable alkoxysilyl group in combination with a specific silane coupling agent (B) in a coating composition. The present invention was completed based on this finding.

[0008] That is, according to the present invention, the following inventions are provided. [1] A coating composition comprising a curable resin (A) and a silane coupling agent (B), The curable resin (A) is represented by the following general formula (1): -X-CH2-SiR 1 Y (OR 2 ) 3-Y ···(1) (In formula (1), X represents a bonding functional group in which a heteroatom having an unshared electron pair is bonded to a methylene group bonded to a silicon atom contained in a hydrolyzable silyl group, R 1 and R 2 each independently represents a hydrocarbon group having 1 to 10 carbon atoms, Y represents 0, 1 or 2. and having a hydrolyzable alkoxysilyl group represented by A coating composition, wherein the silane coupling agent (B) comprises an aminosilane compound. [2] The coating composition according to [1], wherein the silane coupling agent (B) further contains a polymerizable unsaturated silane compound as a silane compound other than the aminosilane compound. [3] The coating composition according to [2], wherein the polymerizable unsaturated silane compound is a vinyl silane compound. [4] The coating composition according to [2] or [3], wherein the mass ratio of the aminosilane compound to the polymerizable unsaturated silane compound in the coating composition is 0.1 or more and 10 or less. [5] The coating composition according to any one of [1] to [4], further comprising inorganic particles (C). [6] The coating composition according to any one of [1] to [5], further comprising an ultraviolet absorber (D). [7] The coating composition according to any one of [1] to [6], further comprising a light stabilizer (E). [8] The coating composition according to any one of [1] to [7], which is used for concrete structures. [9] A coating film formed from the coating composition according to any one of claims 1 to 8.

[10] A method for repairing or reinforcing a concrete structure, comprising: A method comprising a step of coating the surface of a concrete structure with the coating composition according to any one of [1] to [8].

[11] A method for preventing spalling of a concrete structure, comprising: A method comprising a step of coating the surface of a concrete structure with the coating composition according to any one of [1] to [8]. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a coating composition that has excellent low-temperature curing properties and is capable of forming a coating film that is excellent in performance such as visibility, flame retardancy, crack tracking ability, spalling resistance, and adhesion. Furthermore, according to the present invention, it is possible to provide a coating composition that has excellent long-term storage stability. Furthermore, according to the present invention, it is possible to provide a coating film formed from such a coating composition. Furthermore, according to the present invention, it is also possible to provide a method for repairing or reinforcing a concrete structure using such a coating composition, and a method for preventing spalling of a concrete structure. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will now be described in more detail. In this specification, the term "solid content" refers to the content remaining after excluding volatile components such as organic solvents from the coating composition, and refers to the components that constitute the coating film when cured.

[0011] <Paint composition> The coating composition of the present invention contains a curable resin (A) and a specific silane coupling agent (B). The coating composition of the present invention may further contain inorganic particles (C), an ultraviolet absorber (D), a light stabilizer (E), and other components. In the present invention, by using a curable resin (A) having a specific hydrolyzable alkoxysilyl group in combination with a specific silane coupling agent (B), a moisture-curable, one-component coating composition can be obtained that reacts with moisture in the air to cure even at low temperatures. The term "one-component" refers to the fact that the coating composition can be applied directly to a desired location without being mixed with other curing agents. The coating film formed from such a coating composition exhibits excellent visibility, flame retardancy, crack-following ability, peeling resistance, and adhesion. The components constituting the coating composition are described in detail below.

[0012] (Curable resin (A)) The curable resin (A) has a hydrolyzable alkoxysilyl group represented by the following general formula (1): The curable resin has a hydrolyzable alkoxysilyl group represented by the following general formula (1) at its terminal, preferably at both terminals, and may also have a hydrolyzable alkoxysilyl group on a side chain. -X-CH2-SiR 1 Y (OR 2 ) 3-Y ···(1) In formula (1), X represents a bonding functional group in which a heteroatom having an unshared electron pair is bonded to a methylene group bonded to a silicon atom contained in a hydrolyzable silyl group. 1 and R 2 each independently represents a hydrocarbon group having 1 to 20 carbon atoms. Y represents 0, 1 or 2.

[0013] The above-mentioned linking functional group is a functional group having a structure connecting the hydrolyzable silyl group and the main chain. Such a linking functional group is preferably a functional group having at least one of a (thio)urethane bond, a (thio)urea bond, a (thio)substituted urea bond, a (thio)ester bond, a (thio)ether bond, etc. The linking functional group is not limited to the above-mentioned groups, as long as a heteroatom having an unshared electron pair is bonded to a methylene group bonded to a silicon atom contained in the hydrolyzable silicon group. The heteroatom refers to an atom other than carbon and hydrogen, and in this embodiment, for example, N, O, F, Si, P, S, Cl, Br, I, etc. can be used.

[0014] The main chain skeleton of the curable resin is not particularly limited, but may be a main chain skeleton commonly used in silicone resins and modified silicone resins. Examples of main chain skeletons include polyoxyalkylene, vinyl polymer, saturated hydrocarbon polymer, unsaturated hydrocarbon polymer, polyether, polyester, polycarbonate, polyamide, polysiloxane, etc. Among these, polyoxyalkylene and polyether are preferred. When two or more curable resins are used in combination, they may each have the same main chain skeleton selected from these, or they may have different main chain skeletons.

[0015] The curable resin can be produced by a conventionally known method. For example, a conventionally known method includes a method of reacting a polyol compound with an isocyanate methylalkoxysilane compound. Another conventionally known method includes a method of synthesizing a urethane prepolymer by reacting a polyol compound with a polyisocyanate compound, and then reacting the urethane prepolymer with a compound having a heteroatom bonded to an active hydrogen group at the α-position, such as an aminomethylalkoxysilane compound.

[0016] As shown in the above formula (1), the silicon atom can be bonded to an alkoxy group (OR 2 ) are bonded to the remaining bond of the silicon atom, and a hydrocarbon group (R 1 ) are bonded to 2 to 0. R 1 and R 2 are each preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms. For example, an alkoxy group (OR 2 Examples of the alkyl group (R) bonded to the remaining bond of the silicon atom include a methoxy group, an ethoxy group, and a propoxy group, and preferably a methoxy group or an ethoxy group. 1 ) includes a methyl group, an ethyl group, a propyl group, etc., and is preferably a methyl group or an ethyl group.

[0017] In the present invention, the resin of the moisture-curing one-component coating composition is a curable resin having a hydrolyzable alkoxysilyl group represented by the general formula (1) above, rather than a conventional epoxy resin. This allows for sufficient curing even under low-temperature conditions, making application possible even under low-temperature conditions such as winter. Furthermore, transparency is increased compared to epoxy resins, improving visibility. Furthermore, flame retardancy is improved compared to epoxy resins. Furthermore, in the present invention, the use of a curable resin (α-type structure) having a hydrolyzable alkoxysilyl group with a methylene group in the general formula (1) above provides higher reactivity than a curable resin (γ-type structure) having a hydrolyzable alkoxysilyl group in which the methylene group in the general formula (1) is replaced with an n-propylene group, thereby allowing for sufficient curing even under low-temperature conditions, making application possible. Furthermore, the use of a curable resin with an α-type structure provides various properties, such as improved storage stability and reduced risk of problems such as tackiness.

[0018] From the viewpoints of room temperature and low temperature curing properties and storage stability, the content of the curable resin is preferably 40% by mass or more and 98% by mass or less, more preferably 50% by mass or more and 95% by mass or less, and even more preferably 55% by mass or more and 90% by mass or less, based on 100% by mass of the solid content of the coating composition.

[0019] (Silane coupling agent (B)) As the silane coupling agent (B), at least an aminosilane compound is used. The aminosilane compound is a compound having an amino group and a hydrolyzable silyl group. Examples of the aminosilane compound include 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(6-aminohexyl)aminomethyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, 4-amino-3-dimethylbutyltrimethoxysilane, 4-amino-3-dimethylbutylmethyldimethoxysilane, and 4-amino-3-dimethylbutyltriethoxysilane. , 4-amino-3-dimethylbutylmethyldiethoxysilane, bis(3-trimethoxypropyl)amine, bis(3-methyldimethoxypropyl)amine, N-phenylaminopropyltrimethoxysilane, N-phenylaminopropylmethyldimethoxysilane, N-ethylaminoisobutyltrimethoxysilane, N-ethylaminoisobutylmethyldimethoxysilane, N-butylaminopropyltrimethoxysilane, N-butylaminopropylmethyldimethoxysilane, diethylenetriaminopropyltrimethoxysilane, N-(2-propenyl)aminopropyltrimethoxysilane, hydrochloride salt of N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane, and condensation reaction products derived therefrom. These may be used alone or in combination of two or more.

[0020] As the silane coupling agent (B), it is preferable to use a silane compound other than the aminosilane compound in combination. As the other silane compound, a compound having a polymerizable unsaturated group such as a vinyl group or a (meth)acryloyl group and a hydrolyzable silyl group (polymerizable unsaturated silane compound) can be used. Examples of the polymerizable unsaturated silane compound include vinyl silane compounds such as vinyl trimethoxysilane, vinyl triethoxysilane, vinyl triacetoxysilane, vinyl tris(ethyl methyl ketoxime)silane, p-trimethoxysilylstyrene, p-triethoxysilylstyrene, p-trimethoxysilyl-α-methylstyrene, and p-triethoxysilyl-α-methylstyrene; γ-(meth)acryloxypropyl trimethoxysilane, γ-(meth)acryloxypropyl triethoxysilane, γ-(meth)acryloxypropyl methyldimethoxysilane, γ-(meth)acryloxypropyl methyldiethoxysilane, γ-(meth)acryloxypropyl methoxyethoxysilane; Examples of (meth)acryloylsilane compounds include (3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, and tris-(trimethoxysilylpropyl)isocyanurate. Among these, vinylsilane compounds are preferred. These compounds may be used alone or in combination of two or more.

[0021] From the viewpoints of room temperature and low temperature curing properties and storage stability, the content of the silane coupling agent (B) is preferably 0.1 mass % or more and 50 mass % or less, more preferably 0.5 mass % or more and 20 mass % or less, and even more preferably 1 mass % or more and 10 mass % or less, based on 100 mass % of the solid content of the coating composition.

[0022] The mass ratio of the aminosilane compound to the polymerizable unsaturated silane compound in the coating composition is preferably from 0.1 to 10, more preferably from 0.5 to 5.0, even more preferably from 1.0 to 4.5, still more preferably from 1.3 to 4.0, and most preferably from 1.5 to 3.5. When the mass ratio of the aminosilane compound to the polymerizable unsaturated silane compound in the coating composition is within the above numerical range, it is possible to obtain a coating composition that can form a coating film that is excellent in visibility, flame retardancy, crack followability, peeling resistance, and adhesion, while further improving the room temperature and low temperature curing properties and storage stability of the coating composition.

[0023] (Inorganic particles (C)) Examples of inorganic particles (C) include silica, calcium carbonate, potassium feldspar, kaolin, clay, talc, barium sulfate, magnesium carbonate, and glass flakes. Among these, silica is preferred. These may be used alone or in combination of two or more.

[0024] From the viewpoint of preventing sagging during application, the content of inorganic particles is preferably 0.1% by mass or more and 20% by mass or less, more preferably 0.5% by mass or more and 15% by mass or less, and even more preferably 1% by mass or more and 10% by mass or less, based on 100% by mass of the solid content of the coating composition.

[0025] (Ultraviolet absorber (D)) The ultraviolet absorber (D) is not particularly limited, and conventionally known ultraviolet absorbers can be used. Examples of ultraviolet absorbers include benzotriazole-based ultraviolet absorbers, hydroxyphenyltriazine-based ultraviolet absorbers, and benzophenone-based ultraviolet absorbers. These ultraviolet absorbers may be used alone or in combination of two or more.

[0026] Examples of benzotriazole-based ultraviolet absorbers include 2-[2'-hydroxy-5'-(methacryloyloxymethyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxypropyl)phenyl]-2H-benzotriazole, and 2-[2'-hydroxy-5'-(methacryloyloxyhexyl)phenyl]-2H-benzotriazole. Triazole, 2-[2'-hydroxy-3'-tert-butyl-5'-(methacryloyloxyethyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-tert-butyl-3'-(methacryloyloxyethyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-5-chloro-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-5-chloro-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-5-methoxy-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-5-cyano-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-5-tert-butyl-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-5-nitro-2H-benzotriazole, 2-(2-hydroxy-5-t-butylphenyl)- Examples include 2H-benzotriazole, benzenepropanoic acid-3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy-, C7-9-branched linear alkyl ester, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, and 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol.

[0027] Examples of the hydroxyphenyltriazine ultraviolet absorber include 2-[4-[(2-hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl]4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[4-(2-hydroxy-3-tridecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[4-[(2-hydroxy-3 -(2-ethyl)hexyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2,4-bis(2-hydroxy-4-butyloxyphenyl)-6-(2,4-bis-butyloxyphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-[1-octyloxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine, and the like.

[0028] Examples of benzophenone-based ultraviolet absorbers include 2,2',4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-acetoxyethoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, and 2,2'-dihydroxy-4,4'-dimethoxy-5,5'-disulfobenzophenone disodium salt.

[0029] From the viewpoint of weather resistance, the content of the ultraviolet absorber is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.3% by mass or more and 7% by mass or less, and even more preferably 0.5% by mass or more and 5% by mass or less, based on 100% by mass of the solid content of the coating composition.

[0030] (Light stabilizer (E)) The light stabilizer (E) is not particularly limited, and any conventionally known light stabilizer can be used, and it is preferable to use a hindered amine-based light stabilizer. Examples of light stabilizers include bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, 1-[2-[3-(3,5-t-butyl-4-hydroxyphenyl)propionyloxy]ethyl]-4-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4,5]decane-2,4-dione, and bis-(1,2,2,6,6-pentamethyl-4-piperidyl)-2-(3,5-di-t -butyl-4-hydroxybenzyl)-2-n-butylmalonate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, (Mixed 1,2,2,6,6-pentamethyl-4-piperidyl / tridecyl)-1,2,3,4-butanetetracarboxylate, Mixed{1,2,2,6,6-pentamethyl-4-piperidyl / β,β,β',β'-tetramethyl-3,9-[2,4,8,10-tetraoxaspiro(5,5)undecane]diethyl}-1,2,3,4-butanetetracarboxylate, (Mixed 2,2,6,6-Tetramethyl-4-piperidyl / tridecyl)-1,2,3,4-butanetetracarboxylate, Mixed{2,2,6,6-tetramethyl-4-piperidyl / β,β,β',β'-tetramethyl-3,9-[2,4,8,10-tetraoxaspiro(5,5)undecane]diethyl}-1,2,3,4-butanetetracarboxylate, 2,2,6,6-tetramethyl-4-piperidyl methacrylate, 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, poly[(6-(1,1,3,3-tetramethylbutyl)imino-1,3,5-triazine-2,4-diyl)][(2,2,6,6-Tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)iminol], polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, N,N',N'',N'''-tetrakis-(4,6-bis-(butyl-(N-methyl-2,2,6,6-tetramethylpiperidin-4-yl)amino)-triazine- 2-yl)-4,7-diazadecane-1,10-diamine, polycondensate of dibutylamine-1,3,5-triazine-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethylpiperidyl)butylamine, decanedioic acid bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl)ester, etc.

[0031] From the viewpoint of weather resistance, the content of the light stabilizer is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.2% by mass or more and 7% by mass or less, and even more preferably 0.3% by mass or more and 5% by mass or less, based on 100% by mass of the solid content of the coating composition.

[0032] (Other ingredients) The coating composition of the present invention may contain other components in addition to the above components (A) to (E) as long as the object of the present invention is not impaired. Such other components may include leveling agents, antistatic agents, antioxidants, non-reactive diluents, antifoaming agents, anti-sagging agents, dispersants, heat stabilizers, adhesion improvers, plasticizers, etc., as needed.

[0033] <Method for preparing coating composition> The coating composition of the present invention can be obtained by mixing and stirring the above-mentioned components using a conventionally known device such as a mixer, disperser, stirrer, etc. Examples of such devices include a mixing and dispersion mill, a homodisper, a mortar mixer, a roll, a paint shaker, a homogenizer, etc.

[0034] In the present invention, the coating composition can be diluted with a solvent as needed, for example, to adjust the viscosity to a coating composition suitable for use as a coating composition. The solvent is not particularly limited as long as it dissolves the resin component of the resin composition. Specific examples include aromatic hydrocarbons (e.g., toluene, xylene, and ethylbenzene), esters or ether esters (e.g., ethyl acetate, butyl acetate, and methoxybutyl acetate), ethers (e.g., diethyl ether, tetrahydrofuran, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, and diethylene glycol monoethyl ether), ketones (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, di-n-butyl ketone, and cyclohexanone), alcohols (e.g., methanol, ethanol, n- or i-propanol, n-, i-, sec-, or t-butanol, 2-ethylhexyl alcohol, and benzyl alcohol), amides (e.g., dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc.), sulfoxides (e.g., dimethyl sulfoxide), and mixed solvents of two or more of these.

[0035] <Coating film> The coating film according to the present invention is formed from the above-described coating composition. There are no particular limitations on the thickness of the coating film, but it is generally 100 to 3,000 μm, preferably 300 to 2,000 μm, and more preferably 500 to 1,000 μm. The coating thickness in the present invention refers to the thickness of the coating film when the cross section of the coating film is observed using an optical microscope, a scanning electron microscope (SEM), or the like. When forming a coating of such a thickness, the desired thickness may be formed by a single coating, or by multiple coatings.

[0036] <Coated substrate> The coated substrate of the present invention is formed by covering a substrate with the coating film. Examples of the substrate include those made of concrete, cement, mortar, fiber-reinforced cement (calcium silicate, slate), gypsum, stone, etc.

[0037] The method for producing the substrate with a coating film according to the present invention is not particularly limited, but it can be produced, for example, by a production method including the following steps [1] and [2]. [1] A step of applying the coating composition to a substrate to form a coating film. [2] A process of drying the obtained coating film to form a dry coating film.

[0038] The method for applying the coating composition of the present invention is not particularly limited, and conventionally known methods can be used without limitation. Examples include airless spray coating, air spray coating, roller coating, and brush coating. The viscosity of the coating composition can be adjusted appropriately by adding the above-mentioned solvent depending on the coating method. For example, when applying by roller, it is preferable to adjust the viscosity of the coating composition to 100 dPa·s. Note that, to ensure good adhesion between the coating film formed from the coating composition and the substrate, it is preferable to clean and remove surface deposits such as rust, grease, dust, and salt.

[0039] The method for drying the applied coating composition (coating film) is not particularly limited, and although it can be dried by heating to about 5 to 60°C to shorten the drying and curing times, it is usually dried by leaving it at room temperature in the atmosphere for about 1 to 14 days.

[0040] <Applications of coating compositions> The coating composition of the present invention can be applied to the surface of a substrate by simple means such as a roller or brush to form a coating film that is visible to the substrate. The coating film has excellent adhesion, flexibility that allows it to conform to cracks in the substrate, and toughness that prevents the substrate from peeling off. Furthermore, the coating film has high transparency, allowing for easy inspection and maintenance.

[0041] The coating composition having the above-mentioned properties is preferably applied to concrete structures constructed using concrete. Examples of such concrete structures include large structures such as viaducts, tunnels, port facilities, and dams. The coating film of the present invention is suitable for application to viaducts and tunnels because of its excellent adhesion, crack-following ability, and peeling resistance. Furthermore, other application targets include structures constructed using iron, such as bridges, plants, ships, etc. Because the coating film of the present invention has excellent adhesion and visibility, it can also be used as an anticorrosion paint that allows the condition of the substrate to be confirmed.

[0042] A coating composition having the above-described effects can be used for reinforcing or repairing concrete structures, and is particularly useful as a coating composition for preventing concrete fragments from peeling off. That is, the present invention can provide a method for repairing or reinforcing a concrete structure by coating the surface of the concrete structure with the above-described coating film. Furthermore, the present invention can provide a method for preventing concrete fragments from peeling off by coating the surface of the concrete structure with the above-described coating film.

[0043] Furthermore, when the surface of a concrete structure is coated with the above-mentioned coating film, the coating film has the property that the deterioration state of the concrete structure underneath can be visually inspected from above the coating film, i.e., the coating film has high visibility relative to the substrate. Therefore, the present invention can provide a method for inspecting a concrete structure in which the surface of a concrete structure is coated with a coating film and the deterioration state of the concrete structure can be visually inspected from above the coating film. [Example]

[0044] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0045] The following materials were used to prepare the coating compositions: α-type silane-modified polypropylene glycol (manufactured by Wacker Asahi Kasei Silicone Co., Ltd., product name: GENIOSIL XT50) γ-type silane-modified polypropylene glycol (manufactured by Wacker Asahi Kasei Silicone Co., Ltd., product name: GENIOSIL STP-E35) Polypropylene glycol (plasticizer, manufactured by Sanyo Chemical Industries, Ltd., product name: Sannix PP-400) Epoxy resin (ADEKA Corporation, product name: ADEKA Resin EP-4080E) Glycidyl ether (Huntsman, product name: Erisys GE-35) Polyamidoamine 1 (manufactured by Evonik Japan Co., Ltd., product name: ANCAMIDE910) Rubber-modified amine (Hypro ATBN 1300X16, manufactured by Huntsman) Aminosilane compound (3-aminopropyltrimethoxysilane, manufactured by Wacker Asahi Kasei Silicones Co., Ltd., product name: GENIOSIL GF96) Vinylsilane compound (vinyltrimethoxysilane, manufactured by Wacker Asahi Kasei Silicone Co., Ltd., product name: GENIOSIL XL10) γ-Glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBM-403 Fumed silica (manufactured by Nippon Aerosil Co., Ltd., product name: AEROSIL RY 300) Glass flakes (manufactured by Nippon Sheet Glass Co., Ltd., product name: Glass Flake RCF-015) UVA (ultraviolet absorber, manufactured by BASF Japan Ltd., product name: TINUVIN 1130) HALS (light stabilizer, manufactured by BASF Japan Ltd., product name: TINUVIN 292) Defoaming agent (BYK Japan Co., Ltd., product name: BYK-1790) Anti-sagging agent (BYK Japan Co., Ltd., product name: BYK-410) Vinylon fiber (manufactured by Kuraray Co., Ltd., product name: VF1203-2)

[0046] [Examples 1 to 9, Comparative Examples 1 to 4] [Preparation of coating composition] A coating composition was prepared by stirring and mixing each component according to the formulation shown in Table 1.

[0047] [Evaluation of coating composition] The coating compositions prepared above were evaluated for the following properties, and the evaluation results are shown in Table 2.

[0048] (1-1) Curability (at room temperature) The coating composition prepared above was applied to a substrate (glass plate) at room temperature (23°C) to form a coating film 650 μm thick. The condition of the coating film after 12 hours and 24 hours was evaluated according to the following criteria. [Evaluation criteria] ⊚: The coating had hardened after 12 hours. ◯: The coating had hardened after 24 hours. ×: The coating film was not cured after 24 hours.

[0049] (1-2) Curability (low temperature) The coating composition prepared above was applied to a substrate (glass plate) at a low temperature (0°C) to form a coating film 650 μm thick. The condition of the coating film after 12 hours and 24 hours was evaluated according to the following criteria. [Evaluation criteria] ⊚: The coating had hardened after 12 hours. ◯: The coating had hardened after 24 hours. ×: Not cured after 24 hours.

[0050] (2) Visibility A straight line was drawn in the center of a 300mm x 300mm x 60mm concrete pavement board (substrate) specified in JIS A5371 using a 1mm thick black oil-based marker. The coating composition prepared above was applied to the substrate with a trowel to a dry coating thickness of 600-700μm, and then dried for 7 days under conditions of a temperature of 23°C and a relative humidity of 50%. The ability to visually observe the straight line on the dried coating was evaluated according to the following criteria. [Evaluation criteria] ○: A clear straight line was visible to the naked eye. △: A straight line was visible to the naked eye, but was unclear. ×: A straight line could not be visually recognized.

[0051] (3) Flame retardancy The coating composition prepared above was applied to a substrate (a B5-size slate board) and then dried for 7 days at 23°C. The flame retardancy of the dried coated substrate was measured in accordance with the "Railway Vehicle Material Flammability Test" and evaluated according to the following criteria. Specifically, the test plate was held at a 45° incline, and placed on a stand made of a material with low thermal conductivity such as cork so that the center of the bottom of the fuel container was 25.4 mm (1 inch) vertically below the center of the underside (burning surface) of the test material. 0.5 cc of pure ethyl alcohol was poured into the container and ignited, and the container was left to burn out, and the condition of the coating after the test was evaluated. [Evaluation criteria] ○: No carbonization of the coating film was observed. △: Slight carbonization observed in the coating film. ×: The coating film is carbonized.

[0052] (4) Crack followability The crack followability of the coating composition prepared above was evaluated in accordance with Section 6, Crack Followability Test Method, of the Quality Test Methods for Concrete Coating Materials in the "Handbook of Steel Highway Bridges." Specifically, the crack tracking test was conducted in accordance with Section 6) Crack Tracking Test Method of the Quality Test Methods for Concrete Coating Materials in the "Steel Highway Bridge Corrosion Prevention Handbook." The coating composition prepared above was applied to a polypropylene resin plate with a trowel to a dry coating thickness of 600-700 μm. After curing at 23°C for 120 hours, the plate was heated at 80°C for 60 minutes and allowed to cool. The resulting coating film was then peeled off from the polypropylene resin plate to obtain a free coating film. After confirming that the free coating film was free of deformation and pinholes, a punching machine was used to obtain test specimens. Using a materials testing machine capable of maintaining a constant crosshead separation speed (Shimadzu Corporation, Shimadzu Compact Tabletop Tester, Model "EZ-L"), the test specimens were tensioned at a crosshead separation speed of 5 mm / min, a gauge length of 40 mm, and a test temperature of 23°C. During the tensile test, a tensile load-displacement curve was recorded, with the tensile load on the vertical axis and the displacement on the horizontal axis. From the tensile load-displacement curve obtained in the test, the elongation at yield or the elongation at the moment of break (displacement length) of the test piece was divided by the gauge length (40 mm) and multiplied by 100 to calculate the elongation percentage (%), which was used to evaluate crack followability. A higher elongation percentage indicates better crack followability.

[0053] (5) Peeling resistance 1 (Push-out test 1) The peeling prevention properties of the coating compositions prepared above were evaluated in accordance with the Japan Society of Civil Engineers standard JSCE-K533-2010 "Push-out test method for surface coating materials applied to prevent peeling of concrete pieces." Specifically, the test was carried out using a type 300 (400mm x 600mm x 60mm) of cover-type U-shaped gutter cover (hereinafter referred to as "cover") specified in JIS A5372. A circular core with a diameter of 100mm was drilled from the center of the cover using a concrete core drill. The core was drilled from the back surface (the surface opposite to the surface to which the clear coating composition is applied (hereinafter referred to as the "application surface")) toward the application surface, to a depth of 55mm from the back surface. Next, the surface of the workpiece was treated using a diamond cup, and the lid was then immersed in water maintained at 23°C for 24 hours with the workpiece surface facing up. Next, the top of the lid was lifted out of the water, and with the lower 30 mm of the lid still submerged, water droplets on the workpiece surface were removed with a rag. Within 5 minutes of lifting the top of the lid out of the water, the coating composition prepared above was applied with a trowel to a central area of 400 mm x 400 mm of the workpiece surface to a dry coating thickness of 600 to 700 μm. The application was performed with the lower 30 mm of the lid still submerged. The lid was then cured for 28 days at 23°C with the lower 30 mm of the lid still submerged, to obtain a test specimen.

[0054] The specimen material testing machine (manufactured by A&D Co., Ltd., model "RTC-1350A") obtained above was used to conduct the test according to the following test method. The specimen was placed on a fulcrum with a span of 450 mm, with the coated surface facing downward, and it was confirmed that the fulcrum was not in contact with the coating. A spherical seat was placed between the core so that the load was applied evenly and vertically to the center of the core. During the loading process, a load-displacement curve was recorded, with the load on the vertical axis and the displacement on the horizontal axis. Loading was first performed at a rate of 1 mm / min until the concrete in the core was destroyed. After the initial load peak was confirmed, loading was continued at 5 mm / min, and the maximum load that appeared thereafter was measured. After measuring the maximum load, loading was terminated when the load had decreased to approximately 50% of the maximum load. Three specimens prepared under the same conditions were tested as a set. In the above test, the load was temporarily stopped at each displacement of 10mm, 20mm, and 30mm, and the peeling area was marked on the specimen and photographed. The test was terminated when the final load-bearing capacity was confirmed. A load-displacement curve was drawn from the load and displacement stroke data obtained in the test, and the maximum load at a displacement of 10mm or more was determined. The maximum load was determined for three specimens, and the average value P was calculated, and this value was used as the punching strength. The average value P was rounded to one decimal place. The evaluation criteria are shown below. [Evaluation criteria] ○: The punching strength was 0.5 kN or more. ×: The punching strength was less than 0.5 kN.

[0055] (6) Anti-peeling property 2 (Push-out test 2) In order to apply the coating composition to a location where peeling resistance is particularly required, the punching strength was measured in the same manner as in the above-mentioned peeling resistance 1, except that the coating composition prepared above was applied twice and a mesh such as a vinylon mesh or glass cloth was used in combination. The evaluation criteria are as follows: [Evaluation criteria] ○: The punching strength was 1.5 kN or more. ×: The punching strength was less than 1.5 kN.

[0056] (7)Adhesion The peeling prevention properties of the coating compositions prepared above were evaluated in accordance with the Japan Society of Civil Engineers standard JSCE-K531-2010 "Test method for adhesion strength of surface coating materials." Specifically, mortar with a water-cement ratio of 50% and a sand-cement ratio of 3 was molded using a metal formwork with internal dimensions of 70 mm × 70 mm × 20 mm, cured for 24 hours at a temperature of 20°C and a relative humidity of 80%, and then demolded to obtain a test substrate. Next, the test substrate was cured in water for 6 days at a temperature of 20°C. After the underwater curing was completed, the test substrate was further cured for 7 days at a temperature of 23°C and a relative humidity of 50%, and then the underside of the molded substrate was thoroughly polished using No. 150 abrasive paper specified in JIS R 6252. The coating composition prepared above was applied to the obtained test substrate with a trowel so that the dry coating thickness was 600 to 700 μm, and the substrate was aged for 28 days at a temperature of 23° C. and a relative humidity of 50%. The following tests were carried out using the obtained test substrate with the coating film as a test specimen.

[0057] The test specimen was placed horizontally in an atmosphere of 23°C and 50% relative humidity, adhesive was applied to a portion of the coating side, a 40mm square steel jig for upper tension was gently placed on top and lightly rubbed to adhere, a 1kg weight was placed on top of it, any adhesive that had spilled out around the periphery was wiped off, and the test specimen was left to stand for 24 hours.The weight was then removed, and a square cut was made in the test specimen along the periphery of the steel jig for upper tension that had been adhered to the specimen, reaching a depth of 1mm from the substrate surface. The lower tensile steel jig and steel backing plate were attached to the upper tensile steel jig of the incised test specimen, and a materials testing machine (manufactured by A&D Co., Ltd., model "RTC-1350A") was used to apply a tensile force perpendicular to the coating film on the surface of the test specimen at a loading rate of 1500 N / min until fracture, determining the maximum tensile load T (N). The above test was performed twice, and the adhesion was evaluated using the average of the bond strengths according to the following criteria. The bond strength was calculated using the following formula. The evaluation results are shown in Table 2. Adhesion strength (N / mm 2 )=T / 1600 [Evaluation criteria] ○: Adhesion strength is 1.5N / mm 2 End ×: Adhesion strength is 1.5N / mm 2 less than

[0058] (8) Storage stability The coating composition prepared above was stored in a plastic container at a temperature of 60°C and a relative humidity of 90% for 30 days, and the state of the coating composition was checked and evaluated according to the following evaluation criteria. [Evaluation criteria] ◎: No abnormalities. ○: A thin film is formed on the surface of the paint, but the inside of the paint remains liquid. ×: Hardening has progressed to the interior of the paint and it has solidified.

[0059] (9) Crack detection A test substrate was prepared in the same manner as in the adhesion test, and a mortar measuring 70 mm x 70 mm x 20 mm with a water-cement ratio of 50% and a sand-cement ratio of 3 was obtained. The coating composition prepared above was applied to the obtained test substrate with a trowel so that the dry coating thickness was 600 to 700 μm, and the coating was aged for 28 days at a temperature of 23° C. and a relative humidity of 50%. Next, the back side of the obtained test specimen was struck with a mallet or the like to generate a crack in the test specimen, and an evaluation was made based on whether the crack could be visually detected. [Evaluation criteria] ○: Cracks can be clearly detected. △: Very slight cracks can be detected. ×: No cracks were detected.

[0060] [Table 1]

[0061] [Table 2]

Claims

1. A coating composition comprising a curable resin (A) and a silane coupling agent (B), The curable resin (A) is represented by the following general formula (1): -X-CH ２ -SiR １ Ｙ (OR ２ ) ３－Ｙ ・・・(1) (In formula (1), X represents a bonding functional group in which a heteroatom having an unshared electron pair is bonded to a methylene group bonded to a silicon atom contained in a hydrolyzable silyl group, R １ and R ２ each independently represents a hydrocarbon group having 1 to 10 carbon atoms, Y represents 0, 1 or 2. and having a hydrolyzable alkoxysilyl group represented by The content of the curable resin (A) is 50% by mass or more and 90% by mass or less, based on 100% by mass of the solid content of the coating composition; The content of the silane coupling agent (B) is 5% by mass or more and 20% by mass or less based on 100% by mass of the solid content of the coating composition, the silane coupling agent (B) is an aminosilane compound and the other silane compound is a vinylsilane compound; A coating composition, wherein the mass ratio of the aminosilane compound to the vinylsilane compound in the coating composition is 1.5 or more and 10 or less.

2. A paint composition as described in claim 1, wherein the content of the curable resin (A) is 55 mass% or more and 90 mass% or less, based on 100 mass% of the solid content of the paint composition.

3. A coating composition according to claim 1 or 2, wherein the content of the silane coupling agent (B) is 5% by mass or more and 13% by mass or less, based on 100% by mass of the solid content of the coating composition.

4. 4. The coating composition according to claim 1, wherein the mass ratio of the aminosilane compound to the vinylsilane compound in the coating composition is 1.5 or more and 5.0 or less.

5. A paint composition described in any one of claims 1 to 4, wherein the content of the aminosilane compound is 3 mass% or more and 10 mass% or less.

6. The coating composition according to any one of claims 1 to 5, further comprising inorganic particles (C).

7. The coating composition according to any one of claims 1 to 6, further comprising an ultraviolet absorber (D).

8. The coating composition according to any one of claims 1 to 7, further comprising a light stabilizer (E).

9. The coating composition according to any one of claims 1 to 8, which is used on a concrete structure.

10. A coating film formed from the coating composition according to any one of claims 1 to 9.

11. A method for repairing or reinforcing a concrete structure, comprising: A method comprising the step of coating a surface of a concrete structure with the coating composition according to any one of claims 1 to 9.

12. A method for preventing spalling of a concrete structure, comprising: A method comprising the step of coating a surface of a concrete structure with the coating composition according to any one of claims 1 to 9.

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