Paint composition for concrete coating

Abstract

To provide a paint composition for concrete coating that enables formation of a coating film exhibiting superior film physical properties and superior crack-following performance on a concrete substrate.SOLUTION: A paint composition for concrete coating, comprising an epoxy resin (A) and polymer particles (B) having a core-shell structure including a core layer and a shell layer, in respective specific amounts, the composition containing no solvent or containing a specific amount of a solvent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a coating composition for coating concrete. [Background technology]

[0002] Compositions containing epoxy resins are used in a variety of applications, such as concrete deterioration inhibitors and concrete floor paints (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-211245 [Patent Document 2] Japanese Patent Application Publication No. 63-130676 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned conventional techniques are not sufficient from the viewpoint of achieving both coating film properties and crack followability, and there is room for further improvement.

[0005] One embodiment of the present invention has been made in consideration of the above-mentioned problems, and its object is to provide a novel coating composition for concrete coating that can provide a coating film that has excellent coating film properties and crack-following ability in the concrete substrate. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above problems and have completed the present invention.

[0007] That is, a coating composition for concrete coating according to one embodiment of the present invention comprises the following components.

[0008] [1] A polymer particle (B) having a core-shell structure including an epoxy resin (A) and a core layer and a shell layer, A coating composition for coating concrete, wherein the content of the polymer particles (B) is 1 part by mass to 100 parts by mass relative to 100 parts by mass of the epoxy resin (A), The coating composition for concrete does not contain a solvent, or contains more than 0% by mass and not more than 50% by mass of a solvent relative to 100% by mass of the coating composition for concrete.

[0009] [2] The coating composition for concrete coating according to [1], wherein the coating composition for concrete coating does not contain the solvent.

[0010] [3] The coating composition for concrete painting described in [1] or [2], wherein the solvent is contained in an amount of more than 0% by mass and not more than 40% by mass based on 100% by mass of the coating composition for concrete painting.

[0011] [4] The coating composition for concrete painting according to any one of [1] to [3], wherein the amount of the solvent emitted from the coating film formed by curing the coating composition for concrete painting is 50% by mass or less relative to 100% by mass of the coating composition for concrete painting.

[0012] [5] A coating film obtained by curing the coating composition for coating concrete according to any one of [1] to [4].

[0013] [6] The coating film according to [5], wherein the average thickness of the coating film is 0.1 mm or more.

[0014] [7] The coating film according to [5] or [6], wherein the coating film is a transparent coating film.

[0015] [8] A concrete structure having the coating film according to any one of [5] to [7] on a concrete substrate.

[0016] [9] The concrete structure according to [8], wherein the concrete structure is a flooring material.

[0017]

[10] The concrete structure according to [8], wherein the concrete structure is a bridge.

[0018]

[11] The coating composition for concrete coating according to any one of [1] to [5], wherein the epoxy resin (A) comprises at least one selected from the group consisting of bisphenol A epoxy resins, bisphenol F epoxy resins, and alicyclic epoxy resins.

[0019]

[12] The coating composition for coating concrete according to any one of [1] to

[11] , wherein the epoxy resin (A) has an average epoxy equivalent of 100 or more but less than 1,000.

[0020]

[13] The coating composition for concrete coating according to any one of [1] to

[12] , wherein the polymer particles (B) have a core layer made of one or more types of rubber selected from the group consisting of diene rubber, (meth)acrylate rubber, and organosiloxane rubber.

[0021]

[14] The coating composition for concrete further contains an epoxy curing agent (C), The coating composition for coating concrete according to any one of [1] to

[13] , wherein the content of the epoxy curing agent (C) is 1 to 200 parts by mass per 100 parts by mass of the epoxy resin (A).

[0022]

[15] The coating composition for concrete further contains an epoxy-based reactive diluent (D), The coating composition for coating concrete according to any one of [1] to

[14] , wherein the content of the epoxy-based reactive diluent (D) is 1.0 to 150.0 parts by mass per 100 parts by mass of the epoxy resin (A). [Effects of the Invention]

[0023] According to one embodiment of the present invention, it is possible to provide a novel coating composition for concrete coating, which can provide a coating film that is excellent in coating film properties and crack-following ability in a concrete substrate. DETAILED DESCRIPTION OF THE INVENTION

[0024] One embodiment of the present invention will be described below, but the present invention is not limited thereto. The present invention is not limited to the respective configurations described below, and various modifications are possible within the scope of the claims. Furthermore, embodiments or examples obtained by combining the technical means disclosed in different embodiments or examples are also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment. All academic literature and patent documents described in this specification are incorporated herein by reference. Furthermore, unless otherwise specified in this specification, the term "A to B" representing a numerical range means "greater than or equal to A (including and greater than A) and less than or equal to B (including and less than B)."

[0025] In this specification, the "epoxy resin (A)," "polymer particles (B)," "epoxy curing agent (C)," and "epoxy-based reactive diluent (D)" may also be referred to as "component (A)," "component (B)," "component (C)," and "component (D)," respectively.

[0026] [1. Paint composition for concrete coating] A coating composition for concrete according to one embodiment of the present invention contains an epoxy resin (A) and polymer particles (B) having a core-shell structure comprising a core layer and a shell layer, wherein the content of the polymer particles (B) is 1 to 100 parts by mass per 100 parts by mass of the epoxy resin (A), and the content of the solvent in 100% by mass of the coating composition for concrete is 0 to 50% by mass.

[0027] In this specification, the term "coating composition for concrete painting" may be referred to as "composition," and the term "coating composition for concrete painting according to one embodiment of the present invention" may be referred to as "the composition."

[0028] Because of the above-described configuration, the present composition has the advantage of being able to provide a coating film with excellent coating film properties and crack-following ability. Herein, coating film properties are evaluated by the coating film's "glass transition temperature (°C)." Herein, the coating film's crack-following ability is evaluated by the coating film's "tensile test elongation (%)" and "zero span tension test." Therefore, the coating film's "crack-following ability" can also be referred to as the coating film's "elongation property." The better the coating film's elongation property, the better the coating film's crack-following ability. Because of the above-described configuration, the present composition also has the advantage that the tensile modulus is maintained (does not decrease significantly) even when polymer particles are contained. Furthermore, because the present composition contains an epoxy resin (A), it can also be referred to as an epoxy paint composition. Therefore, the present composition also has the advantage of being able to provide a coating film with excellent barrier properties (e.g., barrier properties against salt, carbon dioxide, water, etc.). The methods for measuring the glass transition temperature (° C.) and tensile test elongation (%) of the coating film, as well as the method for testing the coating film in zero span tension, will be described in detail in the examples below.

[0029] Generally, coating films obtained by curing epoxy coating compositions containing epoxy resins as the primary component have a high glass transition temperature, resulting in a high modulus of elasticity at room temperature and excellent durability and barrier properties. Therefore, these compositions are suitable for use as concrete deterioration inhibitors and concrete floor coatings. However, coating films obtained by curing these compositions have low toughness and elongation properties, or in other words, poor crack tracking, leaving room for improvement. The technology disclosed in Patent Document 2 (JP 63-130676 A) increases the coating film's elongation properties and improves crack tracking, but tends to significantly lower the coating film's glass transition temperature, making it difficult to achieve both coating film properties (glass transition temperature) and crack tracking properties (elongation). Because of the above-described composition, this composition has the advantage of being able to provide coating films with significantly improved crack tracking properties while maintaining high coating film properties (glass transition temperature). In other words, it has the advantage of being able to provide a coating film that has an excellent balance between coating film properties (glass transition temperature) and crack followability (glass transition temperature).

[0030] <Ingredients> (Epoxy resin (A)) The present composition contains an epoxy resin as component (A). In this specification, "epoxy resin" means "a resin having at least one epoxy group in one molecule." The epoxy resin (A) preferably has two or more epoxy groups in one molecule. Various epoxy resins can be used as the epoxy resin.

[0031] Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD ​​type epoxy resins, bisphenol S type epoxy resins, glycidyl ester type epoxy resins, glycidylamine type epoxy resins, novolac type epoxy resins, glycidyl ether type epoxy resins of bisphenol A propylene oxide adducts, hydrogenated bisphenol A (or F) type epoxy resins, fluorinated epoxy resins, flame-retardant epoxy resins such as glycidyl ether of tetrabromobisphenol A, p-oxybenzoic acid glycidyl ether ester type epoxy resins, m-aminophenol Examples of epoxy resins include aryl-type epoxy resins, diaminodiphenylmethane-based epoxy resins, various alicyclic epoxy resins, N,N-diglycidylaniline, N,N-diglycidyl-o-toluidine, triglycidyl isocyanurate, divinylbenzene dioxide, resorcinol diglycidyl ether, chelate-modified epoxy resins, rubber-modified epoxy resins, urethane-modified epoxy resins, hydantoin-type epoxy resins, epoxidized products of unsaturated polymers such as petroleum resins, aminoglycidyl ether resins, and epoxy compounds obtained by addition reaction of the above-mentioned epoxy resins with bisphenol A (or F) or polybasic acids.

[0032] Examples of commercially available bisphenol A type epoxy resins include those sold under the trade name jER by Mitsubishi Chemical Corporation (e.g., jER828, jER825, jER827, jER828EL, jER828US, jER828XA, jER834, jER1001, jER1002, jER1004, jER1007, jER1009, jER1010), those sold under the trade name EPON by Momentive Specialty Chemicals, Inc. (e.g., EPON 1510, EPON 1310, EPON 828, EPON 872, EPON 1001, EPON 1004, EPON 2004), and those sold under the trade name DER by Olin Epoxy Co. (e.g., DER 331, DER 332, DER 336, and DER 439), those commercially available from ADEKA Corporation under the trade name ADEKA RESIN (e.g., EP-4100, EP-4300, EP-4400, EP-4530, EP-4504), and those commercially available from DIC Corporation under the trade name EPICLON (e.g., EPICLON 840, EPICLON 850).

[0033] Examples of commercially available bisphenol F epoxy resins include, but are not limited to, those sold by Mitsubishi Chemical Corporation under the trade name jER (e.g., jER806, jER806H, jER807, jER4005P, jER4007P, jER4010P), those sold by Olin Epoxy Co. under the trade name DER (e.g., DER 334), those sold by ADEKA Corporation under the trade name ADEKA RESIN (e.g., EP-4901, EP-4901E), and those sold by DIC Corporation under the trade name EPICLON (e.g., EPICLON 830).

[0034] Alicyclic epoxy resins are compounds containing (i) one or more saturated or unsaturated aliphatic hydrocarbon rings and (ii) one or more epoxy groups in the molecule, and also include epoxy resins containing cycloalkane rings. Examples of alicyclic epoxy resins include 3,4-epoxycyclohexylmethyl (3,4-epoxy) cyclohexane carboxylate, tetrahydroindene diepoxide, vinylcyclohexene oxide, dipentene dioxide, bis(3,4-epoxycyclohexylmethyl) adipate, dicyclopentadiene dioxide, bis(2,3-epoxycyclopentyl) ether, 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol, and epoxidized butanetetracarboxylic acid tetrakis. Examples include bis-(3-cyclohexenylmethyl)-modified epsilon-caprolactone, bi-7-oxabicyclo[4.1.0]heptane, dodecahydrobisphenol A diglycidyl ether, dodecahydrobisphenol F diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, hexahydrophthalic acid diglycidyl ester, hexahydroterephthalic acid diglycidyl ester, and diglycidyl ether of 2,2-bis(4-hydroxycyclohexyl)propane (generic name: hydrogenated bisphenol A liquid epoxy resin). The alicyclic epoxy resin preferably contains one or more selected from the group consisting of 3,4-epoxycyclohexylmethyl(3,4-epoxy)cyclohexanecarboxylate, 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol, epoxidized butanetetracarboxylic acid tetrakis-(3-cyclohexenylmethyl)-modified epsilon-caprolactone, and diglycidyl ether of 2,2-bis(4-hydroxycyclohexyl)propane, and more preferably consists of only one or more selected from this group. More preferably, the alicyclic epoxy resin contains 3,4-epoxycyclohexylmethyl(3,4-epoxy)cyclohexanecarboxylate, and even more preferably consists of only 3,4-epoxycyclohexylmethyl(3,4-epoxy)cyclohexanecarboxylate.This composition has the advantages of having a low viscosity and excellent processability, and also of providing a coating film obtained by curing the composition that has excellent strength, elastic modulus, and heat resistance (high Tg).

[0035] Examples of epoxy compounds obtained by subjecting an epoxy resin to an addition reaction with a polybasic acid or the like include an addition reaction product of a dimer of tall oil fatty acid (dimer acid) with a bisphenol A-type epoxy resin, as described in WO 2010-098950.

[0036] The epoxy resin is not limited to these, and any commonly used epoxy resin may be used. These epoxy resins may be used alone or in combination of two or more.

[0037] In this specification, polyalkylene glycol diglycidyl ethers, glycol diglycidyl ethers, diglycidyl esters of aliphatic polybasic acids, glycidyl ethers of dihydric or higher polyhydric aliphatic alcohols, and monoepoxides are not included in the term "epoxy resins." These polyalkylene glycol diglycidyl ethers, glycol diglycidyl ethers, diglycidyl esters of aliphatic polybasic acids, glycidyl ethers of dihydric or higher polyhydric aliphatic alcohols, and monoepoxides have relatively low viscosities (e.g., 500 mPa·s or less at 25°C) compared to the epoxy resins described above. In other words, in this specification, epoxy resins with a viscosity of 500 mPa·s or less at 25°C are not included in the term "component (A)."

[0038] As the chelate-modified epoxy resin, for example, the resins described in paragraphs

[0018] to

[0019] of WO2016-163491 can be used.

[0039] The rubber-modified epoxy resin is a reaction product obtained by reacting rubber with an epoxy group-containing compound, and has an average of 1.1 or more epoxy groups per molecule, preferably 2 or more. Examples of the rubber-modified epoxy resin include resins described in paragraphs

[0124] to

[0132] of WO2016-163491.

[0040] As the urethane-modified epoxy resin, for example, the resins described in paragraphs

[0133] to

[0135] of the pamphlet of WO2016-163491 can be used.

[0041] Among these epoxy resins, those having at least two epoxy groups in one molecule are preferred because they have high curability, provide a coating film with excellent flexibility, and are excellent in improving the elongation properties of the coating film when polymer particles are added, as described below. In particular, compounds having two epoxy groups in one molecule are preferred.

[0042] Among the above-mentioned epoxy resins, bisphenol A epoxy resins, bisphenol F epoxy resins, and alicyclic epoxy resins produce coating films with high elastic modulus, excellent heat resistance and adhesion, and are relatively inexpensive. Therefore, it is preferable that component (A) contains one or more resins selected from the group consisting of bisphenol A epoxy resins, bisphenol F epoxy resins, and alicyclic epoxy resins.

[0043] The total content of the bisphenol A epoxy resin, bisphenol F epoxy resin, and alicyclic epoxy resin per 100 parts by mass of component (A) is preferably 10 to 100 parts by mass, more preferably 30 to 100 parts by mass, more preferably 50 to 100 parts by mass, more preferably 70 to 100 parts by mass, more preferably 80 to 100 parts by mass, even more preferably 90 to 100 parts by mass, and particularly preferably 95 to 100 parts by mass. The upper limit of the total content of the bisphenol A epoxy resin, bisphenol F epoxy resin, and alicyclic epoxy resin per 100 parts by mass of component (A) may be less than 100 parts by mass. This configuration has the advantages of providing a composition with low viscosity and excellent processability, and of providing a coating film obtained by curing the composition with excellent strength, elastic modulus, and heat resistance (high Tg). The total content of bisphenol A epoxy resin, bisphenol F epoxy resin, and alicyclic epoxy resin may be 100 parts by mass per 100 parts by mass of component (A). In other words, component (A) may be composed solely of bisphenol A epoxy resin, solely of bisphenol F epoxy resin, solely of alicyclic epoxy resin, solely of bisphenol A epoxy resin and alicyclic epoxy resin, solely of bisphenol F epoxy resin and alicyclic epoxy resin, solely of bisphenol A epoxy resin and bisphenol F epoxy resin, or solely of bisphenol A epoxy resin, bisphenol F epoxy resin, and alicyclic epoxy resin.

[0044] Furthermore, since a coating composition for concrete painting that can provide a coating film with excellent heat resistance can be obtained at a low cost, it is more preferable that component (A) contains a bisphenol A epoxy resin, and it is particularly preferable that component (A) is (consisting only of) a bisphenol A epoxy resin. Furthermore, since a coating composition for concrete painting that can provide a coating film with excellent weather resistance can be obtained at a relatively low cost, it is more preferable that component (A) contains a diglycidyl ether of 2,2-bis(4-hydroxycyclohexyl)propane (generic name: hydrogenated bisphenol A liquid epoxy resin), and it is particularly preferable that component (A) is (consisting only of) a diglycidyl ether of 2,2-bis(4-hydroxycyclohexyl)propane (generic name: hydrogenated bisphenol A liquid epoxy resin).

[0045] The average epoxy equivalent of the epoxy resin (A) is preferably 100 or more and less than 1,000, more preferably 120 or more and less than 500, even more preferably 140 or more and less than 250, and particularly preferably 160 or more and less than 220. This configuration has the advantage that the resulting composition has low viscosity and good workability.

[0046] In this specification, the term "average epoxy equivalent" refers to the molecular weight per epoxy group contained in a compound having an epoxy group (for example, an epoxy resin), and is specifically a value calculated based on the following formula: Average epoxy equivalent (g / eq) = mass average molecular weight (Mw) of a compound / average number of epoxy groups per molecule of a compound. The epoxy equivalent can also be measured in accordance with JIS K7236.

[0047] When the epoxy resin (A) is a mixture of multiple epoxy resins with different average epoxy equivalents, the "average epoxy equivalent of the epoxy resin (A)" refers to the sum of the values ​​obtained by multiplying the average epoxy equivalent (g / eq) of each epoxy resin by the content ratio of each epoxy resin in the epoxy resin (A). For example, when the epoxy resin (A) (100% by mass) is a mixture of epoxy resin A1 (30% by mass) and epoxy resin A2 (70% by mass) with different average epoxy equivalents, the average epoxy equivalent of the epoxy resin (A) is a value calculated based on the following formula: Average epoxy equivalent (g / eq) of epoxy resin (A) = {average epoxy equivalent (g / eq) of epoxy resin A1 × 0.3} + {average epoxy equivalent (g / eq) of epoxy resin A2 × 0.7}.

[0048] Bisphenol A epoxy resins having an epoxy equivalent of 100 or more but less than 1,000, bisphenol F epoxy resins having an epoxy equivalent of 100 or more but less than 1,000, and alicyclic epoxy resins having an epoxy equivalent of 100 or more but less than 1,000 are all liquids or low-melting solids at room temperature, providing excellent handleability. Therefore, from the standpoint of excellent handleability, it is particularly preferable that component (A) contains one or more selected from the group consisting of bisphenol A epoxy resins having an epoxy equivalent of 100 or more but less than 1,000, bisphenol F epoxy resins having an epoxy equivalent of 100 or more but less than 1,000, and alicyclic epoxy resins having an epoxy equivalent of 100 or more but less than 1,000. This configuration has the advantage that the coating film obtained by curing the composition has an even better elastic modulus.

[0049] The total content of the bisphenol A epoxy resin having an epoxy equivalent of 100 or more but less than 1000, the bisphenol F epoxy resin having an epoxy equivalent of 100 or more but less than 1000, and the alicyclic epoxy resin having an epoxy equivalent of 100 or more but less than 1000, in 100% by mass of component (A), is preferably 60% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. This configuration has the advantages of providing a coating film with a high elastic modulus and superior impact resistance, heat resistance, and adhesion. The total content of the bisphenol A epoxy resin having an epoxy equivalent of 100 or more but less than 1000, the bisphenol F epoxy resin having an epoxy equivalent of 100 or more but less than 1000, and the alicyclic epoxy resin having an epoxy equivalent of 100 or more but less than 1000, in 100% by mass of component (A), may be 100% by mass. In other words, component (A) may be (or may consist of) one or more selected from the group consisting of bisphenol A epoxy resins having an epoxy equivalent of 100 or more and less than 1,000, bisphenol F epoxy resins having an epoxy equivalent of 100 or more and less than 1,000, and alicyclic epoxy resins having an epoxy equivalent of 100 or more and less than 1,000.

[0050] From the viewpoint of the elongation properties of the coating film, the content of component (A) is preferably 60% by mass or more, based on 100% by mass of the total amount of components (A) to (D).

[0051] (Polymer particles (B)) Component (B) is a polymer particle having a core-shell structure comprising a core layer and a shell layer. In this specification, "polymer particle having a core-shell structure comprising a core layer and a shell layer" refers to a particle in which a core layer made of a core polymer and a shell layer made of a shell polymer form a layer structure. In this specification, "polymer particle having a core-shell structure comprising a core layer and a shell layer" may also be referred to as "core-shell polymer particle" or simply as "polymer particle."

[0052] Component (B) (polymer particles) can improve the balance between coating film properties (glass transition temperature) and crack-following ability. In other words, by including component (B), the present composition has the advantage of being able to provide a coating film that has an excellent balance between coating film properties (glass transition temperature) and crack-following ability. Furthermore, by including component (B), the present composition tends to provide a coating film with excellent toughness.

[0053] The polymer particles can be obtained by graft polymerizing a graft-copolymerizable monomer (a monomer for forming a shell layer) in the presence of a core layer to form a shell layer. More specifically, this polymerization operation can be carried out by adding a monomer for forming a shell layer (shell polymer) to a latex of a core polymer prepared in the form of an aqueous polymer latex, and polymerizing the resulting mixture. In the polymer particles, it is preferable that the core polymer and the shell polymer are substantially chemically bonded. Note that in the polymer particles, the core layer and the shell layer do not necessarily form a complete layer structure. The shell layer (shell polymer) need only cover at least a portion of the core layer (core polymer), and need not cover the entire core layer. Furthermore, a portion of the shell layer may penetrate into the core layer.

[0054] Each layer of the polymer particles (B) will be specifically described below.

[0055] <Core layer> The core layer is preferably an elastic core layer having rubber properties in order to improve the balance between the coating film properties (glass transition temperature) of the composition and crack followability.

[0056] The core layer preferably contains a diene rubber, more preferably a diene rubber (e.g., composed solely of a diene rubber), because it effectively improves the balance between the resulting coating film's physical properties (glass transition temperature) and crack followability, effectively improves the impact resistance of the resulting coating film, and is less likely to experience viscosity increases over time due to swelling of the core layer due to its low affinity with component (A). The core layer preferably contains a (meth)acrylate rubber because it allows for a wide range of polymer compositions to be designed by combining various monomers and improves the weather resistance of the coating film. Furthermore, the core layer preferably contains an organosiloxane rubber because it improves the impact resistance at low temperatures without reducing the heat resistance of the coating film and improves the weather resistance of the coating film. In other words, the core layer preferably contains one or more rubbers selected from the group consisting of diene rubbers, (meth)acrylate rubbers, and organosiloxane rubbers.

[0057] (Diene rubber) The diene rubber is preferably a polymer containing 50% by mass to 100% by mass of conjugated diene units and 0% by mass to 50% by mass of structural units derived from vinyl monomers other than conjugated diene monomers copolymerizable with the conjugated diene monomers.

[0058] Examples of the conjugated diene monomer from which the conjugated diene units are derived include 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), and 2-chloro-1,3-butadiene.

[0059] These conjugated diene monomers may be used alone or in combination of two or more.

[0060] The content of conjugated diene units in the core layer is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and even more preferably 90% by mass to 100% by mass, based on 100% by mass of all structural units constituting the core layer. When the content of conjugated diene units in the core layer is 50% by mass or more, the balance between the physical properties of the resulting coating film (glass transition temperature) and crack followability can be improved.

[0061] Examples of vinyl monomers other than conjugated diene monomers copolymerizable with conjugated diene monomers include vinyl arenes such as styrene, α-methylstyrene, monochlorostyrene, and dichlorostyrene; vinyl carboxylic acids such as acrylic acid and methacrylic acid; vinyl cyanides such as acrylonitrile and methacrylonitrile; vinyl halides such as vinyl chloride, vinyl bromide, and chloroprene; vinyl acetate; alkenes such as ethylene, propylene, butylene, and isobutylene; and polyfunctional monomers such as diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, and divinylbenzene.

[0062] These vinyl monomers may be used alone or in combination of two or more. As the vinyl monomer other than the conjugated diene monomer copolymerizable with the conjugated diene monomer, styrene is particularly preferred.

[0063] Among diene rubbers, the core layer preferably contains butadiene rubber, which is a homopolymer of 1,3-butadiene, and / or butadiene-styrene rubber, which is a copolymer of 1,3-butadiene and styrene, from the viewpoints of a more effective improvement in the balance between the physical properties (glass transition temperature) and crack followability of the resulting coating film, a more effective improvement in the impact resistance of the resulting coating film, and a lower affinity with component (A) that makes it less likely for the core layer to increase in viscosity over time due to swelling. More preferably, the core layer is butadiene rubber and / or butadiene-styrene rubber (e.g., composed solely of butadiene rubber and / or butadiene-styrene rubber), even more preferably, it contains butadiene rubber, and particularly preferably, it is butadiene rubber (e.g., composed solely of butadiene rubber). Butadiene-styrene rubber is also preferred because it can enhance the transparency of the resulting coating film by adjusting the refractive index.

[0064] ((Meth)acrylate rubber) The (meth)acrylate rubber is preferably a polymer obtained by polymerizing a monomer mixture containing 50% to 100% by mass of (meth)acrylate units and 0% to 50% by mass of structural units derived from vinyl monomers other than the (meth)acrylate monomers that are copolymerizable with the (meth)acrylate monomers. In this specification, "(meth)acrylate" means acrylate and / or methacrylate.

[0065] Examples of the (meth)acrylate monomer from which the (meth)acrylate unit is derived include: (i) alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate; (ii) aromatic ring-containing (meth)acrylates such as phenoxyethyl (meth)acrylate and benzyl (meth)acrylate; (iii) hydroxyalkanol (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate; (iv) glycidyl (meth)acrylates such as glycidyl (meth)acrylate and glycidyl alkyl (meth)acrylate; (v) alkoxyalkyl (meth)acrylates; (vi) allyl alkyl (meth)acrylates such as allyl (meth)acrylate and allyl alkyl (meth)acrylate; (vii) polyfunctional (meth)acrylates such as monoethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate.

[0066] Examples of hydroxyalkyl (meth)acrylates include hydroxy linear alkyl (meth)acrylates (particularly, hydroxy linear C1-6 alkyl (meth)acrylates) such as 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; caprolactone-modified hydroxy (meth)acrylates; hydroxy branched alkyl (meth)acrylates such as α-(hydroxymethyl)methyl acrylate and α-(hydroxymethyl)ethyl acrylate; and hydroxyl group-containing (meth)acrylates such as mono(meth)acrylates of polyester diols (particularly saturated polyester diols) obtained from divalent carboxylic acids (such as phthalic acid) and dihydric alcohols (such as propylene glycol).

[0067] These (meth)acrylate monomers may be used alone or in combination of two or more. The (meth)acrylate unit is preferably one or more selected from the group consisting of an ethyl (meth)acrylate unit, a butyl (meth)acrylate unit, and a 2-ethylhexyl (meth)acrylate unit.

[0068] Examples of vinyl monomers other than (meth)acrylate monomers copolymerizable with (meth)acrylate monomers include (i) vinyl arenes such as styrene, α-methylstyrene, monochlorostyrene, and dichlorostyrene; (ii) vinyl carboxylic acids such as acrylic acid and methacrylic acid; (iii) vinyl cyanides such as acrylonitrile and methacrylonitrile; (iv) vinyl halides such as vinyl chloride, vinyl bromide, and chloroprene; (v) vinyl acetate; (vi) alkenes such as ethylene, propylene, butylene, and isobutylene; and (vii) polyfunctional monomers such as diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, and divinylbenzene.

[0069] The vinyl monomer other than the (meth)acrylate monomer copolymerizable with the (meth)acrylate monomer may be used alone or in combination of two or more. Styrene is particularly preferred as the vinyl monomer other than the (meth)acrylate monomer copolymerizable with the (meth)acrylate monomer, since it can easily increase the refractive index.

[0070] (organosiloxane rubber) Examples of the organosiloxane rubber include: (i) polysiloxane polymers composed of alkyl or aryl di-substituted silyloxy units, such as dimethylsilyloxy, diethylsilyloxy, methylphenylsilyloxy, diphenylsilyloxy, and dimethylsilyloxy-diphenylsilyloxy; and (ii) polysiloxane polymers composed of alkyl or aryl mono-substituted silyloxy units, such as organohydrogensilyloxy in which some of the alkyl groups in the side chains are substituted with hydrogen atoms.

[0071] These polysiloxane polymers may be used singly or in combination of two or more. Among these, dimethylsilyloxy, methylphenylsilyloxy, and dimethylsilyloxy-diphenylsilyloxy are preferred because they can impart heat resistance to the coating film, and dimethylsilyloxy is most preferred because it is easily available.

[0072] From the viewpoints of achieving a low viscosity composition with excellent workability and preventing viscosity increase over time due to swelling of polymer particles caused by low-molecular-weight compounds in the composition, it is preferable that a crosslinked structure be introduced into the core layer. When the core layer has a multilayer structure, it is preferable that the core layer has at least one layer into which a crosslinked structure is introduced. A commonly used method can be used to introduce a crosslinked structure into the core layer, and examples thereof include the following methods. That is, in the production (polymerization) of the core layer, a method can be used in which a crosslinkable monomer such as a polyfunctional monomer and / or a mercapto group-containing compound is mixed with a monomer capable of constituting the core layer, and then polymerized.

[0073] Methods for introducing a crosslinked structure into a diene rubber include the following: (1) a method in which double bonds in the main chain or side chain formed by polymerization of a conjugated diene monomer are crosslinked by adding a crosslinking agent and a vulcanization accelerator; and (2) a method in which polymerization of a conjugated diene monomer is carried out using a radical initiator such as a peroxide, and radical crosslinking is carried out using the radical initiator between double bonds in the main chain or side chain formed by the polymerization, simultaneously with the polymerization.

[0074] Other methods for introducing a crosslinked structure into organosiloxane rubber include: (1) using a polyfunctional alkoxysilane compound in combination with other materials when polymerizing organosiloxane rubber; (2) introducing reactive groups (e.g., (i) mercapto groups and (ii) reactive vinyl groups) into organosiloxane rubber, and then adding (a) an organic peroxide or (b) a polymerizable vinyl monomer to the resulting reaction product to cause a radical reaction; and (3) mixing a crosslinkable monomer such as a polyfunctional monomer and / or a mercapto group-containing compound with other materials when polymerizing organosiloxane rubber, followed by polymerization.

[0075] A polyfunctional monomer can also be said to be a monomer having two or more radically polymerizable reactive groups in the same molecule. The radically polymerizable reactive group is preferably a carbon-carbon double bond. Examples of polyfunctional monomers include (meth)acrylates having an ethylenically unsaturated double bond, such as allyl alkyl (meth)acrylates and allyloxy alkyl (meth)acrylates, and do not include butadiene. Examples of monomers having two (meth)acrylic groups include ethylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, and polyethylene glycol di(meth)acrylates. Examples of the polyethylene glycol di(meth)acrylates include triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and polyethylene glycol (600) di(meth)acrylate. Examples of monomers having three (meth)acrylic groups include alkoxylated trimethylolpropane tri(meth)acrylates, glycerol propoxy tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and tris(2-hydroxyethyl) isocyanurate tri(meth)acrylate. Examples of the alkoxylated trimethylolpropane tri(meth)acrylates include trimethylolpropane tri(meth)acrylate and trimethylolpropane triethoxy tri(meth)acrylate. Further, examples of monomers having four (meth)acrylic groups include pentaerythritol tetra(meth)acrylate and ditrimethylolpropane tetra(meth)acrylate.Further, examples of monomers having five (meth)acrylic groups include dipentaerythritol penta(meth)acrylate.Further, examples of monomers having six (meth)acrylic groups include ditrimethylolpropane hexa(meth)acrylate.The polyfunctional monomers also include diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, divinylbenzene, and the like.

[0076] Examples of mercapto group-containing compounds include alkyl group-substituted mercaptans, allyl group-substituted mercaptans, aryl group-substituted mercaptans, hydroxy group-substituted mercaptans, alkoxy group-substituted mercaptans, cyano group-substituted mercaptans, amino group-substituted mercaptans, silyl group-substituted mercaptans, acid group-substituted mercaptans, halo group-substituted mercaptans, and acyl group-substituted mercaptans. The alkyl group-substituted mercaptans are preferably alkyl group-substituted mercaptans having 1 to 20 carbon atoms, and more preferably alkyl group-substituted mercaptans having 1 to 10 carbon atoms. The aryl group-substituted mercaptans are preferably phenyl group-substituted mercaptans. The alkoxy group-substituted mercaptans are preferably alkoxy group-substituted mercaptans having 1 to 20 carbon atoms, and more preferably alkoxy group-substituted mercaptans having 1 to 10 carbon atoms. The acid group-substituted mercaptan is preferably an alkyl group-substituted mercaptan having a carboxyl group and 1 to 10 carbon atoms, or an aryl group-substituted mercaptan having a carboxyl group and 1 to 12 carbon atoms.

[0077] When a crosslinkable monomer is used in the production (polymerization) of the core layer to introduce a crosslinked structure into the core layer, the resulting core layer may contain structural units derived from the crosslinkable monomer.

[0078] The glass transition temperature (hereinafter sometimes simply referred to as "Tg") of the core layer is not particularly limited. In order to improve the balance between the physical properties (glass transition temperature) and crack followability of the resulting coating film, the Tg of the core layer is preferably 0°C or lower, more preferably -20°C or lower, even more preferably -40°C or lower, and particularly preferably -60°C or lower. In order to improve the strength of the resulting coating film, the Tg of the core layer is preferably 20°C or higher, more preferably 40°C or higher, even more preferably 70°C or higher, and particularly preferably 100°C or higher.

[0079] When the core layer is a copolymer of two or more monomers and the monomers used in the production (polymerization) of the core layer are known, the glass transition temperature Tg of the core layer can be calculated using the FOX formula (Equation 1) shown below.

[0080] 1 / Tg=w1 / Tg1+w2 / Tg2+···+wn / Tgn (Equation 1) Here, Tg1, Tg2, ..., Tgn are the Tg(K) of the homopolymer of the components constituting the core layer (i.e., the monomers used in producing the core layer) 1, 2, ..., n, respectively, and w1, w2, ..., wn are the weight fractions of the components constituting the core layer (i.e., the monomers used in producing the core layer) 1, 2, ..., n, respectively. The Tg of the homopolymer can be determined, for example, from the Polymer Handbook, Fourth Edition (edited by J. Brandup et al., Jphn Wiley & Sons, Inc.). For novel polymers, the peak temperature of the loss tangent (tan δ) measured by viscoelasticity measurement (shear method, measurement frequency: 1 Hz) can be used as the Tg.

[0081] When the monomer used in the production (polymerization) of the core layer is unknown, the Tg of the core layer can also be determined by performing viscoelasticity measurements using a flat plate made of polymer particles (B). Specifically, Tg can be measured as follows: (1) Using a dynamic viscoelasticity measuring device (e.g., DVA-200, manufactured by IT Measurement & Control Co., Ltd.), dynamic viscoelasticity measurements are performed under tensile conditions on a flat plate made of polymer particles (B) to obtain a tan δ graph; (2) The peak temperature of tan δ in the obtained tan δ graph is taken as the glass transition temperature. Here, if multiple peaks are obtained in the tan δ graph, the lowest peak temperature is taken as the glass transition temperature of the core layer.

[0082] The volume average particle diameter of the core layer is not particularly limited, but is preferably 0.03 μm to 2.00 μm, more preferably 0.05 μm to 1.00 μm, more preferably 0.12 μm to 0.50 μm, more preferably 0.12 μm to 0.28 μm, and even more preferably 0.14 to 0.25 μm. When the volume average particle diameter of the core layer is within this range, the core layer can be produced stably. Furthermore, when the volume average particle diameter of the core layer is within this range, the viscosity of the composition can be reduced, resulting in excellent workability and good crack followability of the coating film. The method for measuring the volume average particle diameter of the core layer will be described in detail in the Examples below.

[0083] The core layer may have a single layer structure or a multilayer structure (e.g., a multilayer structure consisting of layers having rubber elasticity). When the core layer has a multilayer structure, the polymer compositions of the layers may be different from each other within the ranges disclosed above.

[0084] The composition of the constituent units of the core layer depends on the composition of the monomer mixture used to form the core layer (monomer mixture for forming the core layer). When the polymerization conversion rate is 100%, the resulting core layer contains constituent units derived from all of the monomers contained in the monomer mixture for forming the core layer.

[0085] In one embodiment of the present invention, an intermediate layer, for example, as described in paragraphs

[0046] to

[0049] of the pamphlet of WO2016-163491, can be provided between the core layer and the shell layer.

[0086] <Shell layer> The shell layer is a polymer obtained by polymerizing a monomer for forming the shell layer. The polymer (shell polymer) constituting the shell layer improves the compatibility between the polymer particles (B) and component (A) and enables the polymer particles (B) to be dispersed in the form of primary particles in the composition and / or a coating film of the composition.

[0087] The type and content ratio of the structural units contained in the shell layer are not particularly limited. From the viewpoint of compatibility and dispersibility of the polymer particles (B) in the composition, the shell layer preferably contains one or more structural units selected from the group consisting of aromatic vinyl units, vinylcyan units, and (meth)acrylate units, and more preferably contains (meth)acrylate units. In particular, the shell layer preferably contains methyl methacrylate units.

[0088] The composition of the structural units of the shell layer depends on the composition of the monomer for forming the shell layer. When the polymerization conversion rate is 100%, the resulting shell layer contains structural units derived from all of the monomers contained in the monomer for forming the shell layer.

[0089] The total content of one or more structural units selected from the group consisting of aromatic vinyl units, vinylcyan units, and (meth)acrylate units in the shell layer is preferably 10.0% by mass to 99.5% by mass, more preferably 50.0% by mass to 99.0% by mass, even more preferably 65.0% by mass to 98.0% by mass, particularly preferably 67.0% by mass to 80.0% by mass, and most preferably 67.0% by mass to 85.0% by mass, based on 100% by mass of the shell layer (shell polymer).

[0090] Specific examples of the aromatic vinyl monomer from which the aromatic vinyl unit is derived include vinylbenzenes such as styrene, α-methylstyrene, p-methylstyrene, and divinylbenzene.

[0091] Specific examples of the vinylcyanide monomer from which the vinylcyanide unit is derived include acrylonitrile and methacrylonitrile.

[0092] Specific examples of the (meth)acrylate monomers from which the (meth)acrylate units are derived are the same as those described in the section "Core Layer" above, and therefore, the description therein is incorporated by reference and will not be repeated here.

[0093] In order to maintain a good dispersion state of the polymer particles (B) in the coating film and composition without agglomeration, it is preferable to chemically bond the polymer particles (B) to the component (A). In order to chemically bond the polymer particles (B) to the component (A), it is preferable that the shell layer has a structural unit derived from a reactive group-containing monomer. In other words, it is preferable that the shell layer contains a reactive group.

[0094] The reactive group is preferably at least one selected from the group consisting of, for example, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an imide group, a carboxylic acid group, a carboxylic anhydride group, a cyclic ester, a cyclic amide, a benzoxazine group, and a cyanate ester group.

[0095] The reactive group is preferably an epoxy group. In other words, the shell layer preferably has a structural unit derived from a monomer having an epoxy group, that is, preferably has an epoxy group. When the shell layer of the polymer particles (B) has an epoxy group, the coating film obtained by curing the composition has the advantage of being excellent in toughness and strength.

[0096] Specific examples of the monomer having an epoxy group include glycidyl group-containing vinyl monomers such as glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and allyl glycidyl ether.

[0097] When the shell layer of the polymer particles (B) contains epoxy groups, the content of epoxy groups in the shell layer relative to the total mass of the shell layer of the polymer particles (B) is preferably from 0 to 5.0 mmol / g, more preferably from 0.1 to 5.0 mmol / g, more preferably from 0.2 to 5.0 mmol / g, more preferably from 0.2 to 4.0 mmol / g, more preferably from 0.2 to 3.0 mmol / g, even more preferably from 0.2 to 2.0 mmol / g, and particularly preferably from 0.3 to 1.5 mmol / g. This configuration suppresses aggregation of the polymer particles (B) and allows the polymer particles (B) to be dispersed in the coating film as primary particles, resulting in the advantageous effect that the coating film obtained by curing the composition has excellent toughness and elongation.

[0098] The monomer having an epoxy group is preferably used to form the shell layer, and more preferably used only to form the shell layer. In other words, it is preferable that the core layer and the intermediate layer do not have an epoxy group.

[0099] From the viewpoint of storage stability of the composition, it is preferable that the shell layer of the polymer particles (B) does not have an epoxy group.

[0100] Specific examples of the reactive group-containing monomer having a hydroxyl group include the above-mentioned hydroxyalkyl (meth)acrylates.

[0101] It is preferable that a crosslinked structure be introduced into the shell layer, since this prevents swelling of the polymer particles (B) in the composition and tends to reduce the viscosity of the composition, improving handleability. When the shell layer has a multilayer structure, it is preferable that the shell layer has at least one layer into which a crosslinked structure is introduced. The method for introducing a crosslinked structure into the shell layer is the same as the method for introducing a crosslinked structure into the core layer, and therefore the description in the section "Core Layer" is incorporated herein and will not be repeated here.

[0102] Examples of polyfunctional monomers that are preferably used to introduce a crosslinked structure into the shell layer include allyl methacrylate and triallyl isocyanurate.

[0103] When a crosslinkable monomer is used in the production (polymerization) of the shell layer to introduce a crosslinked structure into the shell layer, the resulting shell layer may contain constitutional units derived from the crosslinkable monomer.

[0104] The shell layer is preferably a polymer composed only of the following structural units: (a) aromatic vinyl units (particularly preferably styrene units) 0% by mass to 50% by mass (preferably 0% by mass to 35% by mass, more preferably 0% by mass to 20% by mass), (b) vinylcyan units (particularly preferably acrylonitrile units) 0% by mass to 50% by mass (preferably 0% by mass to 30% by mass, more preferably 0% by mass to 20% by mass), (c) (meth)acrylate units ((i) preferably one or more structural units selected from the group consisting of methyl acrylate units, butyl acrylate units, and methyl methacrylate units, (ii) particularly preferably methyl methacrylate units) 0% by mass to 100% by mass (preferably 5% by mass to 100% by mass, more preferably 70% by mass to 95% by mass), and (d) structural units derived from a monomer having an epoxy group (particularly glycidyl methacrylate units) 0% by mass to 50% by mass (preferably 1% by mass to 35% by mass, more preferably 3% by mass to 20% by mass). However, (i) the total of the aromatic vinyl units, vinylcyan units, (meth)acrylate units, and structural units derived from monomers having an epoxy group is 100% by mass, and (ii) 0% by mass means that the structural units may not be included.

[0105] The above-mentioned monomer components may be used alone or in combination of two or more. The shell layer may contain a structural unit derived from a monomer other than the above-mentioned monomers.

[0106] The shell layer may have a single layer structure or a multi-layer structure, and when the shell layer has a multi-layer structure, the polymer compositions of the layers may be different from each other within the ranges disclosed above.

[0107] The glass transition temperature (Tg) of the shell layer is not particularly limited. From the viewpoint of providing a composition with low viscosity and excellent workability, the Tg of the shell layer is preferably 80° C. or lower, more preferably 60° C. or lower, even more preferably 40° C. or lower, and particularly preferably 20° C. or lower. From the viewpoint of improving blocking resistance when handling the polymer particles (B) as a powder, the Tg of the shell layer is preferably 30° C. or higher, more preferably 50° C. or higher, even more preferably 70° C. or higher, and particularly preferably 90° C. or higher.

[0108] When the shell layer is a copolymer of two or more monomers and the monomers used in the production (polymerization) of the shell layer are known, the glass transition temperature Tg of the shell layer can be calculated using the FOX formula (Equation 1) shown below.

[0109] 1 / Tg=w1 / Tg1+w2 / Tg2+···+wn / Tgn (Equation 1) Here, Tg1, Tg2, ..., Tgn are the Tg(K) of the homopolymer of the components constituting the shell layer (i.e., the monomers used in the production of the shell layer) 1, 2, ..., n, respectively, and w1, w2, ..., wn are the weight fractions of the components constituting the shell layer (i.e., the monomers used in the production of the shell layer) 1, 2, ..., n, respectively. The Tg of the homopolymer can be determined, for example, from the Polymer Handbook, Fourth Edition (edited by J. Brandup et al., Jphn Wiley & Sons, Inc.). For novel polymers, the peak temperature of the loss tangent (tan δ) measured by viscoelasticity measurement (shear method, measurement frequency: 1 Hz) can be used as the Tg.

[0110] When the monomer used in the production (polymerization) of the shell layer is unknown, the Tg of the shell layer can also be determined by viscoelasticity measurements using a flat plate made of polymer particles (B). Specifically, the Tg can be measured as follows: (1) Dynamic viscoelasticity measurements are performed under tensile conditions on a flat plate made of polymer particles (B) using a dynamic viscoelasticity measuring device (e.g., DVA-200, manufactured by IT Measurement & Control Co., Ltd.) to obtain a tan δ graph; (2) The peak temperature of tan δ in the obtained tan δ graph is taken as the glass transition temperature. Here, if multiple peaks are obtained in the tan δ graph, the highest peak temperature is taken as the glass transition temperature of the shell layer.

[0111] <Volume average particle size (Mv) of polymer particles (B)> The volume average particle diameter (Mv) of the polymer particles (B) is not particularly limited. From the viewpoint of industrial productivity and workability of the coating composition for concrete coating, the volume average particle diameter (Mv) of the polymer particles (B) is preferably 0.01 μm or more and 2.00 μm or less, more preferably 0.03 μm or more and 0.60 μm or less, more preferably 0.05 μm or more and 0.40 μm or less, more preferably 0.10 μm or more and 0.30 μm or less, more preferably 0.15 μm or more and 0.30 μm or less, more preferably 0.16 μm or more and 0.28 μm or less, more preferably 0.17 μm or more and 0.27 μm or less, and even more preferably 0.18 μm or more and 0.25 μm or less. When the volume average particle diameter (Mv) of the polymer particles (B) is (a) 0.01 μm or more, the viscosity of the composition is low, resulting in good workability, and when it is (b) 2.00 μm or less, the polymerization time of the polymer particles (B) is short, resulting in high industrial productivity. The method for measuring the volume average particle diameter (Mv) of the polymer particles (B) will be described in detail in the Examples below.

[0112] In the present composition, the polymer particles (B) are preferably dispersed in the state of primary particles. In this specification, "the polymer particles (B) are dispersed in the state of primary particles" (hereinafter also referred to as "primary dispersion") means that the polymer particles (B) are dispersed substantially independently (without adhering (cohesion)). The dispersion state of the polymer particles (B) in the composition can be confirmed, for example, by dissolving a part of the composition in a solvent such as methyl ethyl ketone, subjecting the obtained solution to a particle size measurement device using laser light scattering, or the like, and measuring the particle size of the polymer particles (B) in the solution.

[0113] Furthermore, the "stable dispersion" of the polymer particles (B) means a state in which the polymer particles (B) are dispersed steadily under normal conditions for a long period of time without aggregation, separation, or precipitation in the continuous layer. It is also preferable that the distribution of the polymer particles (B) in the continuous layer does not change substantially, and that the "stable dispersion" can be maintained even when the composition is heated within a safe range to reduce the viscosity and stirred.

[0114] The polymer particles (B) may be used alone or in combination of two or more kinds.

[0115] <Method for producing polymer particles (B)> (Method of manufacturing the core layer) The core layer constituting the polymer particles (B) can be formed by, for example, emulsion polymerization, suspension polymerization, microsuspension polymerization, etc. As the emulsion polymerization, suspension polymerization, microsuspension polymerization, etc., the methods described in WO 2005 / 028546 and WO 2006 / 070664 can be appropriately used.

[0116] (Method of forming shell layer and intermediate layer) When the polymer particles (B) contain an intermediate layer, the intermediate layer can be formed by polymerizing a monomer for forming the intermediate layer by known radical polymerization. When the rubber elastic material constituting the core layer is obtained as an emulsion, the polymerization of the monomer for forming the intermediate layer is preferably carried out by emulsion polymerization.

[0117] The shell layer can be formed by polymerizing a monomer for forming the shell layer by known radical polymerization. When the precursor of the core layer or the polymer particles (B) configured by coating the core layer with an intermediate layer is obtained as an emulsion, the polymerization of the monomer for forming the shell layer is preferably carried out by emulsion polymerization. For example, the method described in WO 2005 / 028546 can be used as the emulsion polymerization method.

[0118] In emulsion polymerization, an emulsifier (dispersant) is used.

[0119] Examples of emulsifiers include (i) (i-1) various acids such as alkyl or aryl sulfonic acids typified by dioctylsulfosuccinic acid and dodecylbenzenesulfonic acid; alkyl or aryl ether sulfonic acids; alkyl or aryl sulfuric acids typified by dodecyl sulfate; alkyl or aryl ether sulfuric acids; alkyl or aryl substituted phosphoric acids; alkyl or aryl ether substituted phosphoric acids; N-alkyl or aryl sarcosinic acids typified by dodecyl sarcosinic acid; alkyl or aryl carboxylic acids typified by oleic acid and stearic acid; and alkyl or aryl ether carboxylic acids; as well as (i-2) anionic emulsifiers (dispersants) such as alkali metal salts or ammonium salts of these acids; (ii) nonionic emulsifiers (dispersants) such as alkyl or aryl substituted polyethylene glycol; and (iii) dispersants such as polyvinyl alcohol, alkyl substituted cellulose, polyvinylpyrrolidone, and polyacrylic acid derivatives.

[0120] These emulsifiers (dispersants) may be used alone or in combination of two or more.

[0121] It is preferable to use a small amount of emulsifier (dispersant) as long as it does not impair the dispersion stability of the aqueous latex of polymer particles (B). Furthermore, the higher the water solubility of the emulsifier (dispersant), the more preferable it is. High water solubility makes it easier to wash off the emulsifier (dispersant) with water, and can easily prevent adverse effects on the final coating film.

[0122] When emulsion polymerization is employed, peroxides (for example, organic peroxides), chain transfer agents, surfactants, and the like can be used as needed.

[0123] The polymerization conditions such as polymerization temperature, pressure, deoxidation, etc., may be within known ranges.

[0124] The content of component (B) in the composition is 1 to 100 parts by mass, preferably 3 to 90 parts by mass, more preferably 5 to 80 parts by mass, even more preferably 10 to 75 parts by mass, and particularly preferably 15 to 70 parts by mass, per 100 parts by mass of component (A). This configuration has the advantages of lowering the viscosity of the composition and providing excellent workability, as well as providing an excellent balance between the physical properties (glass transition temperature) and crack followability of the coating film obtained by curing the composition.

[0125] (solvent) The composition may or may not contain a solvent. Examples of the solvent include organic solvents such as volatile organic compounds (hereinafter, sometimes abbreviated as "VOCs," an acronym for Volatile Organic Compounds). More specific examples of the solvent include toluene, xylene, N-butanol, isopropyl alcohol, methyl isobutyl ketone, methyl ethyl ketone, acetone, cyclohexanone, turpene, and mineral spirits. Among these, turpene and / or mineral spirits are preferred as the solvent because of their minimal impact on the human body and the environment.

[0126] Volatile organic compounds (VOCs) can be released into the atmosphere. For example, a composition containing a volatile organic compound as a solvent can release the volatile organic compound (solvent) from a coating film formed by curing the composition during and after curing. Since this reduces the amount of VOCs released into the atmosphere, it is preferable that the composition does not contain a solvent (the solvent content is 0% by mass).

[0127] On the other hand, from the viewpoint of providing a composition with low viscosity and excellent workability, the composition preferably contains a solvent. When the coating composition for concrete contains a solvent, the content of the solvent is greater than 0% by mass and not more than 50% by mass, or may be greater than 0% by mass and not more than 40% by mass, or may be 0.1% by mass to 30% by mass, or may be 0.5% by mass to 20% by mass, based on 100% by mass of the coating composition for concrete. This configuration has the advantages of providing a composition with low viscosity and excellent workability, and having relatively little impact on the human body and / or the environment.

[0128] (Epoxy hardener (C)) The present composition preferably further comprises an epoxy curing agent as component (C). In this specification, the term "epoxy curing agent" refers to a compound capable of curing the epoxy resin (A). When the composition comprises component (C), i.e., an epoxy curing agent, there is an advantage that the composition can be cured to obtain a coating film in a relatively short time.

[0129] The epoxy curing agent (C) preferably has an active hydrogen group. In this specification, the term "active hydrogen group" refers to a functional group capable of reacting with an epoxy group. The number of active hydrogen groups per molecule of the epoxy curing agent is not particularly limited, but is preferably 2 or more, more preferably 3 or more, even more preferably 3.5 or more, and particularly preferably 4 or more. This configuration provides the coating composition for concrete coating with the advantage of excellent rapid curing properties.

[0130] As the epoxy curing agent (C), an amine-based curing agent is preferably used. The amine-based curing agent is at least one selected from the group consisting of aliphatic amines, alicyclic amines, amidoamines, amine-terminated polyethers, amine-terminated butadiene nitrile rubbers, modified aliphatic amines, modified alicyclic amines, modified amidoamines, modified amine-terminated polyethers, and modified amine-terminated butadiene nitrile rubbers. The epoxy curing agent (C) may be used alone or in combination of two or more. The use of the amine-based curing agent as the epoxy curing agent (C) has the advantage of providing a coating composition for concrete coating that has excellent adhesion and fast curing properties.

[0131] <Low-temperature epoxy curing agent> Furthermore, the epoxy curing agent (C) preferably has reactivity with epoxy groups at around room temperature (e.g., 5°C to 50°C or less). In other words, the epoxy curing agent (C) preferably has reactivity with epoxy groups at lower temperatures than epoxy curing agents for heat curing. In this specification, a "curing agent that has reactivity with epoxy groups at around room temperature (e.g., 5°C to 50°C or less), in other words, has reactivity with epoxy groups at lower temperatures than epoxy curing agents for heat curing" may be referred to as a "low-temperature epoxy curing agent." When the present composition contains a low-temperature epoxy curing agent as component (C), the epoxy curing agent (C), when used in combination with the polymer particles (B), has the advantage of achieving both excellent fast curing and good crack followability of the coating film without the need for heat treatment at high temperatures above 50°C.

[0132] From the viewpoint of the elongation properties of the resulting coating film, the epoxy curing agent (C) preferably contains one or more selected from the group consisting of amine-terminated polyethers and amine-terminated butadiene nitrile rubbers, among the above-mentioned amine-based curing agents. Furthermore, from the viewpoint of curability, it is more preferable that the epoxy curing agent (C) further contains amine-terminated butadiene nitrile rubbers. From the viewpoint of the strength and elastic modulus of the resulting coating film, the epoxy curing agent (C) preferably contains one or more selected from the group consisting of aliphatic amines, alicyclic amines, amidoamines, modified aliphatic amines, modified alicyclic amines, and modified amidoamines, among the above-mentioned amine-based curing agents. Furthermore, from the viewpoint of curability, it is preferable that the epoxy curing agent (C) contains one or more selected from the group consisting of aliphatic amines, amidoamines, modified aliphatic amines, and modified amidoamines. From the viewpoint of the heat resistance of the resulting coating film, it is even more preferable that the epoxy curing agent (C) is at least one selected from the group consisting of alicyclic amines and modified alicyclic amines.

[0133] In the present composition, the epoxy curing agent (C) preferably contains 5 wt% or more of amidoamine, more preferably 10 wt% or more, even more preferably 20 wt% or more, and particularly preferably 30 wt% or more, based on 100 wt% of the epoxy curing agent (C). This configuration has the advantage that the resulting coating film has excellent curability.

[0134] From the viewpoint of the physical properties (glass transition temperature) of the resulting coating film, the epoxy curing agent (C) preferably contains an aliphatic amine.

[0135] In this composition, the epoxy curing agent (C) preferably contains 2 wt% or more of the amine-terminated polyether, more preferably 5 wt% or more, even more preferably 10 wt% or more, and particularly preferably 15 wt% or more, based on 100 wt% of the epoxy curing agent (C). This configuration has the advantage of being able to obtain a second component of a coating composition for concrete that has excellent workability at low temperatures (low viscosity at low temperatures).

[0136] Examples of the aliphatic amine include chain aliphatic polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenediamine, diethylaminopropylamine, and hexamethylenediamine, and aliphatic aromatic amines such as metaxylenediamine.

[0137] Examples of the alicyclic amine include N-aminoethylpiperazine, bis(4-amino-3-methylcyclohexyl)methane, menthenediamine, isophoronediamine, 4,4'-methylenebis(cyclohexylamine), 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, which is a type of spiroacetal diamine, norbornanediamine, tricyclodecanediamine, and 1,3-bisaminomethylcyclohexane.

[0138] The amidoamine is a compound produced by condensation of a dimer (dimer acid) of tall oil fatty acid with a polyamine such as triethylenetetramine or tetraethylenepentamine, and examples of commercially available amidoamines include Vegichem Green V140 and Vegichem Green V115.

[0139] The amine-terminated polyether has a polyether backbone and preferably has 1 to 4 (preferably 1.5 to 3) amino and / or imino groups per molecule on average. Commercially available amine-terminated polyethers include Jeffamine D-230, Jeffamine D400, Jeffamine D2000, Jeffamine D4000, and Jeffamine T-5000 manufactured by Huntsman.

[0140] The amine-terminated butadiene nitrile rubber is a polybutadiene / acrylonitrile copolymer having an average of preferably 1 to 4 (more preferably 1.5 to 3) amino and / or imino groups per molecule, and an acrylonitrile monomer content in the main chain of 5 to 40% by mass (more preferably 10 to 35% by mass, and even more preferably 15 to 30% by mass). Commercially available amine-terminated rubbers include Hypro 1300X16 ATBN manufactured by Huntsman.

[0141] Examples of modified amine curing agents include (i) polyamine epoxy resin adducts, which are reaction products of various polyamines such as the above-mentioned aliphatic amines and alicyclic amines with less than an equivalent amount of epoxy resin, and (ii) ketimines, which are dehydration reaction products of polyamines with ketones such as methyl ethyl ketone and isobutyl methyl ketone.

[0142] More specific examples of the mercaptan curing agent include pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(2-(3-sulfanylbutanoyloxy)ethyl)-1,3,5-triazinane-2,4,6-trione, trimethylolpropane tris(3-mercaptobutyrate), thiol-terminated polyether, and thiol-terminated polysulfide.

[0143] From the viewpoint of the heat resistance and elongation properties of the resulting coating film, the ratio of the number of moles of epoxy groups in the epoxy resin (A) to the number of moles of active hydrogen groups in the epoxy curing agent (C) (number of moles of epoxy groups / number of moles of active hydrogen groups) is preferably from 0.5 to 1.6, more preferably from 1.1 to 1.6, even more preferably from 1.1 to 1.5, and particularly preferably from 1.2 to 1.4.

[0144] The content of the epoxy curing agent (C) relative to 100 parts by weight of the epoxy resin (A) is preferably 1 to 200 parts by weight, more preferably 50 to 200 parts by weight, even more preferably 75 to 180 parts by weight, and particularly preferably 100 to 160 parts by weight, from the viewpoints of the strength and fast curing properties of the resulting coating film. One type of component (C) may be used alone, or two or more types may be used in combination.

[0145] The present composition is preferably substantially free of aromatic amines, since the resulting coating film has excellent elongation properties when heated. "Substantially free of aromatic amines" means that the aromatic amine content per 100 parts by weight of the concrete coating composition is 1000 ppm or less. Examples of aromatic amines include metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

[0146] <Epoxy curing agent active at high temperatures> In this specification, a "curing agent reactive with epoxy groups at high temperatures" may be referred to as a "high-temperature epoxy curing agent." A high-temperature epoxy curing agent can also be considered an epoxy curing agent for heat curing. The present composition may contain, as component (C), (i) only a low-temperature epoxy curing agent, (ii) only a high-temperature epoxy curing agent, or (iii) a combination of a low-temperature epoxy curing agent and a high-temperature epoxy curing agent.

[0147] Examples of high-temperature epoxy curing agents include acid anhydride curing agents, boron trifluoride-amine complexes, dicyandiamide, and organic acid hydrazides, as described in International Publication No. 2022-188807. The present composition preferably does not contain a high-temperature epoxy curing agent.

[0148] When the present composition contains a high-temperature epoxy curing agent as component (C), the content of the high-temperature epoxy curing agent is preferably from 0.1 to 30 parts by weight, more preferably from 0.5 to 20 parts by weight, even more preferably from 1 to 15 parts by weight, and particularly preferably from 2 to 10 parts by weight, per 100 parts by weight of the total amount of epoxy curing agent (C).

[0149] (Epoxy-based reactive diluent (D)) The composition preferably further comprises an epoxy-based reactive diluent as component (D). In this specification, the term "epoxy-based reactive diluent" refers to a compound having at least one epoxy group per molecule and a viscosity of 500 mPa·s or less at 25°C. When the composition contains component (D), i.e., an epoxy-based reactive diluent, the coating film obtained by curing the composition at low temperatures has the advantage of having sufficient elongation properties.

[0150] Examples of the epoxy-based reactive diluent include polyalkylene glycol diglycidyl ether, glycol diglycidyl ether, diglycidyl ester of an aliphatic polybasic acid, glycidyl ether of a dihydric or higher polyhydric aliphatic alcohol, and monoepoxide.

[0151] More specific examples of the polyalkylene glycol diglycidyl ether include polyethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether. More specific examples of the glycol diglycidyl ether include neopentyl glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and cyclohexanedimethanol diglycidyl ether. More specific examples of the diglycidyl esters of aliphatic polybasic acids include dimer acid diglycidyl ester, adipic acid diglycidyl ester, sebacic acid diglycidyl ester, and maleic acid diglycidyl ester. More specific examples of the glycidyl ethers of dihydric or higher polyhydric aliphatic alcohols include trimethylolpropane triglycidyl ether, trimethylolethane triglycidyl ether, castor oil-modified polyglycidyl ether, propoxylated glycerin triglycidyl ether, and sorbitol polyglycidyl ether.

[0152] Examples of monoepoxides include aliphatic glycidyl ethers such as butyl glycidyl ether; aromatic glycidyl ethers such as phenyl glycidyl ether and cresyl glycidyl ether (o-cresyl glycidyl ether); ethers consisting of a glycidyl group and an alkyl group having 8 to 10 carbon atoms, such as 2-ethylhexyl glycidyl ether; ethers consisting of a glycidyl group and a phenyl group having 6 to 12 carbon atoms, which may be substituted with an alkyl group having 2 to 8 carbon atoms, such as p-tert-butylphenyl glycidyl ether; ethers consisting of a glycidyl group and an alkyl group having 12 to 14 carbon atoms, such as dodecyl glycidyl ether (alkyl C12-C14 glycidyl ether); aliphatic glycidyl esters such as glycidyl (meth)acrylate and glycidyl maleate; glycidyl esters of aliphatic carboxylic acids having 8 to 12 carbon atoms, such as versatic acid glycidyl ester, neodecanoic acid glycidyl ester, and lauric acid glycidyl ester; and pt-butylbenzoic acid glycidyl ester.

[0153] The epoxy-based reactive diluent preferably contains an epoxy-based reactive diluent having one epoxy group per molecule. This configuration has the advantages of providing a coating film with excellent adhesion and a composition with excellent storage stability. Examples of epoxy-based reactive diluents having one epoxy group per molecule include neodecanoic acid glycidyl ester, phenyl glycidyl ether, cresyl glycidyl ether, 4-tert-butylphenyl glycidyl ether, and 2-ethylhexyl glycidyl ether.

[0154] The component (D) in the present composition preferably contains, based on 100 mass% of the component (D), 70 mass% or more, more preferably 80 mass% or more, and particularly preferably 90 mass% or more of an epoxy-based reactive diluent having one epoxy group per molecule. The component (D) may contain, based on 100 mass% of the component (D), 100 mass% of an epoxy-based reactive diluent having one epoxy group per molecule; in other words, the component (D) may be composed solely of an epoxy-based reactive diluent having one epoxy group per molecule.

[0155] As the epoxy-based reactive diluent, commercially available products can also be used. Commercially available epoxy-based reactive diluents include YED216M (manufactured by Mitsubishi Chemical, 1,6-hexanediol diglycidyl ether), Cardura E10P (manufactured by Hexion, neodecanoic acid glycidyl ester), ERISYS GE-10 (manufactured by Huntsman, o-cresyl glycidyl ether), 4-tert-butylphenyl glycidyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.), ERISYS GE-6 (manufactured by Huntsman, 2-ethylhexyl glycidyl ether), ERISYS GE-8 (manufactured by Huntsman, alkyl C12-C14 glycidyl ether), ERISYS GE-20 (manufactured by Huntsman, neopentyl glycol diglycidyl ether), ERISYS GE-21 (manufactured by Huntsman, 1,4-butanediol diglycidyl ether), and ERISYS GE-24 (manufactured by Huntsman, polypropylene glycol diglycidyl ether). Each of Cardura E10P, ERISYS GE-10, 4-tert-butylphenyl glycidyl ether, ERISYS GE-6, and ERISYS GE-8 is an epoxy-based reactive diluent having one epoxy group per molecule.

[0156] In the present composition, the amount of component (D) per 100 parts by mass of component (A) is preferably 1.0 to 150.0 parts by mass, more preferably 5.0 to 140.0 parts by mass, more preferably 10.0 to 130.0 parts by mass, even more preferably 15.0 to 120.0 parts by mass, and particularly preferably 20.0 to 100.0 parts by mass. When the amount of component (D) per 100 parts by mass of component (A) is within the above-mentioned range, the coating film obtained by curing the present composition at low temperature has the advantage of having excellent elongation properties.

[0157] (Other ingredients) The composition may contain other components as needed, such as phenolic compounds, reinforcing agents, radical-curing resins, monoepoxides, photopolymerization initiators, expanding agents such as azo-type chemical foaming agents and thermally expandable microballoons, fiber pulp such as aramid pulp, colorants such as pigments and dyes, extender pigments, UV absorbers, antioxidants, stabilizers (antigelling agents), plasticizers, leveling agents, defoamers, silane coupling agents, antistatic agents, flame retardants, lubricants, viscosity reducers, shrinkage reducing agents, organic fillers, thermoplastic resins, desiccants, and dispersants.

[0158] The amount of solvent that evaporates from the coating film obtained by curing the composition is preferably 50% by mass or less, more preferably 0% by mass to 50% by mass, even more preferably 0% by mass to 40% by mass, even more preferably 0% by mass to 30% by mass, and particularly preferably 0% by mass to 20% by mass, relative to 100% by mass of the composition. This configuration has the advantage of having relatively little impact on the human body and / or the environment.

[0159] 2. Method for producing coating composition for concrete coating The present composition is a composition containing at least an epoxy resin (A) and polymer particles (B). The present composition is preferably a composition in which the polymer particles (B) are dispersed in the epoxy resin (A), and more preferably a composition in which the polymer particles (B) are dispersed in the epoxy resin (A) in the state of primary particles.

[0160] Any known method can be used to obtain a composition in which polymer particles (B) are dispersed in epoxy resin (A). For example, a composition in which polymer particles (B) are dispersed in epoxy resin (A) can be obtained by (i) contacting a latex (aqueous latex) containing polymer particles (B) with epoxy resin (A) and then removing unnecessary components such as water, or (ii) extracting the polymer particles (B) in the latex with an organic solvent, mixing the organic solvent dispersion containing polymer particles (B) with epoxy resin (A), and then removing the organic solvent from the resulting mixture. As for method (ii), it is preferable to use the method described in WO 2005 / 28546.

[0161] A method for producing a coating composition for concrete according to one embodiment of the present invention may be configured as follows: A method for producing a coating composition for concrete coating, comprising: a first step of mixing a latex containing polymer particles (B) having a core-shell structure including a core layer and a shell layer with an organic solvent that is partially soluble in water, and then contacting the resulting mixture with water to form aggregates of the polymer particles (B) containing the organic solvent in an aqueous phase; a second step of separating and recovering the aggregates from the aqueous phase and then mixing the aggregates with the organic solvent to obtain an organic solvent dispersion containing the polymer particles (B); and a third step of mixing the organic solvent dispersion with an epoxy resin (A) and then distilling off the organic solvent from the resulting mixture, The coating composition for coating concrete has a content of the polymer particles (B) of 1 part by mass to 100 parts by mass relative to 100 parts by mass of the epoxy resin (A), A method for producing a coating composition for concrete painting, wherein the coating composition for concrete painting does not contain a solvent or contains more than 0 mass % but not more than 50 mass % of a solvent per 100 mass % of the coating composition for concrete painting.

[0162] The "organic solvent partially soluble in water" can be any organic solvent or mixture of organic solvents that can be used without substantial coagulation or precipitation of the polymer particles (B) when the aqueous latex of the polymer particles (B) is mixed with the organic solvent. However, the organic solvent preferably has a solubility in water of 5% by weight or more and 40% by weight or less at 20°C, and more preferably 5% by weight or more and 30% by weight or less. When the solubility in water of the organic solvent partially soluble in water at 20°C is 40% by weight or less, the mixing operation in the first step can be carried out smoothly without coagulating the aqueous latex of the epoxy resin (A). Furthermore, when the solubility in water of the organic solvent partially soluble in water at 20°C is 5% by weight or more, the organic solvent can be sufficiently mixed with the aqueous latex of the epoxy resin (A), and the mixing operation in the first step can be carried out smoothly.

[0163] Specific examples of "organic solvents partially soluble in water" include one or more organic solvents or mixtures thereof selected from esters such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; ketones such as acetone, methyl ethyl ketone, diethyl ketone, and methyl isobutyl ketone; alcohols such as ethanol, (iso)propanol, and butanol; ethers such as tetrahydrofuran, tetrahydropyran, dioxane, and diethyl ether; aromatic hydrocarbons such as benzene, toluene, and xylene; and halogenated hydrocarbons such as methylene chloride and chloroform, and the like, which have a solubility in water at 20°C within the above-mentioned range. Among these, from the viewpoints of affinity with reactive polymerizable organic compounds and ease of availability, organic solvents (mixtures) containing 50% by weight or more of methyl ethyl ketone are more preferably used as organic solvents partially soluble in water, and organic solvents (mixtures) containing 75% by weight or more of methyl ethyl ketone are particularly preferably used.

[0164] A composition in which polymer particles (B) are dispersed in an epoxy resin (A) can also be produced by methods other than those including the above steps (Steps 1 to 3). For example, a method using powdered polymer particles (B) can be used. Specifically, an aqueous latex containing the polymer particles (B) is first used to coagulate the polymer particles (B) by a method such as salting out, and the resulting coagulate is then dried to obtain powdered polymer particles (B). A polymer microparticle composition can also be produced by redispersing the powdered polymer particles (B) in component (A) using a disperser with high mechanical shear force, such as a planetary mixer, a three-roll paint roll, a roll mill, or a kneader. In this case, component (B) can be efficiently dispersed in component (A) by applying mechanical shear force at high temperature to a mixture of components (A) and (B). The temperature during dispersion (the temperature at which shear force is applied) is preferably 50 to 200° C., more preferably 70 to 170° C., even more preferably 80 to 150° C., and particularly preferably 90 to 120° C. When the temperature during dispersion is (a) 50° C. or higher, component (B) can be sufficiently dispersed, and when (b) 200° C. or lower, there is no risk of thermal degradation of components (A) and (B).

[0165] The present composition can be obtained by further mixing component (A) and, if necessary, a solvent, component (C), component (D), and other components with the dispersion of polymer particles (B) in component (A), obtained through steps 1 to 3 above, preferably in the form of primary particles. Furthermore, this production method can obtain the present composition in which polymer particles (B) are dispersed in the form of primary particles. When the present composition contains polymer particles as component (B) and the polymer particles are dispersed in the composition in the form of primary particles, the resulting coating film has the advantage of being even more excellent in elongation properties.

[0166] [3. Coating] A coating film according to one embodiment of the present invention is a coating film obtained by curing the coating composition for concrete described in Section [1. Coating composition for concrete painting]. A coating film according to one embodiment of the present invention may also be a coating film obtained by curing a coating composition for concrete painting obtained by the manufacturing method described in Section [2. Manufacturing method of coating composition for concrete painting]. It can also be said that a coating film according to one embodiment of the present invention comprises the coating composition for concrete painting described in Section [1. Coating composition for concrete painting] or a coating composition for concrete painting obtained by the manufacturing method described in Section [2. Manufacturing method of coating composition for concrete painting].

[0167] In this specification, the "coating film according to one embodiment of the present invention" may be referred to as the "coating film of the present invention."

[0168] The present coating film has the above-mentioned constitution and therefore has the advantage of being excellent in coating film properties and crack followability.

[0169] <Physical properties> The physical properties of the coating film will be described below.

[0170] (Tensile test elongation) The coating film preferably has a tensile test elongation of 4% to 1000%, more preferably 5% to 200%, even more preferably 7% to 100%, and particularly preferably 10% to 50%. This configuration has the advantage of excellent crack followability. The method for measuring the tensile test elongation of the coating film will be explained in detail in the Examples below.

[0171] (tensile modulus) The coating film preferably has a tensile modulus of elasticity of 0.2 GPa to 10 GPa, more preferably 0.5 GPa to 5 GPa, even more preferably 1.0 GPa to 4 GPa, and particularly preferably 1.5 GPa to 3 GPa. This configuration has the advantage of providing excellent durability and barrier properties. The method for measuring the tensile modulus of elasticity of the coating film will be described in detail in the Examples below.

[0172] (Zero span tension test) In this specification, the zero span tension test is evaluated based on the elongation value at break of the coating film. It is intended that the greater the elongation value at break of the coating film, i.e., the better the zero span tension test performance, the better the crack followability.

[0173] (glass transition temperature) The present coating film preferably has a glass transition temperature of 20° C. to 200° C., more preferably 30° C. to 150° C., and even more preferably 40° C. to 100° C. This configuration has the advantage of excellent coating film physical properties.

[0174] (storage modulus) The coating film preferably has a storage modulus of 0.2 GPa to 10 GPa, more preferably 0.5 GPa to 5 GPa, and even more preferably 1.0 GPa to 4 GPa. This configuration has the advantage of providing excellent durability and barrier properties. The method for measuring the storage modulus of the coating film will be described in detail in the Examples below.

[0175] The average thickness of the coating film is preferably 0.1 to 3.0 mm, more preferably 0.2 to 2.0 mm, and even more preferably 0.3 to 1.0 mm. This configuration has the advantage of providing excellent crack-following and blocking properties for the coating film.

[0176] The coating film is preferably a transparent coating film, which has the advantage that the presence or absence of cracks in the concrete substrate can be visually confirmed.

[0177] (Total light transmittance) The transparency of the present coating film can be evaluated by measuring the total light transmittance in accordance with JIS K-7361 using a 3 mm thick cured product obtained by curing the present composition. As mentioned above, the thickness of the present coating film is preferably 3 mm or less, and the actual total light transmittance of the present coating film will be lower than the total light transmittance mentioned above. The present composition preferably has a total light transmittance of 30% to 100%, more preferably 50% to 99%, and even more preferably 70% to 98%. This configuration has the advantage of allowing the presence or absence of cracks in the concrete substrate to be visually confirmed. The method for measuring the total light transmittance of the coating film will be explained in detail in the Examples below.

[0178] [4. Concrete Structures] A concrete structure according to one embodiment of the present invention is a concrete structure having the coating film described in the section [3. Coating Film] on a concrete substrate.

[0179] In this specification, the "concrete structure according to one embodiment of the present invention" may be referred to as the "concrete structure".

[0180] Because of the above-described configuration, the present concrete structure has the advantage of excellent crack follow-up properties.

[0181] The concrete structure is preferably one or more selected from the group consisting of floor materials, bridges, building walls, tunnels, roads and dams. [Example]

[0182] Hereinafter, one embodiment of the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited thereto. One embodiment of the present invention can be carried out by appropriately modifying the following examples within the scope that can comply with the above-mentioned and below-mentioned aims. All embodiments carried out by appropriately modifying the following examples are included within the technical scope of the present invention. In the following examples, comparative examples, and tables, "parts" and "%" mean parts by mass and % by mass, respectively.

[0183] 〔material〕 First, the substances used in the examples and comparative examples are shown below.

[0184] <Epoxy resin (A)> A-1: Bisphenol A epoxy resin (liquid at room temperature) (Mitsubishi Chemical, "jER828", epoxy equivalent: 189g / eq) A-2: Dimer acid modified epoxy resin (Mitsubishi Chemical, "jER871", epoxy equivalent: 409g / eq) <Polymer particles (B)> As the polymer particles (B), polymer particles prepared by the following method were used. As described later, dispersions (M-1 to M-3) in which the prepared polymer particles (B) were dispersed in the epoxy resin (A-1) were prepared and used in the examples.

[0185] 1. Formation of the core layer Production Example 1-1: Preparation of polybutadiene rubber latex (R-1) A 100 L pressure-resistant polymerization reactor was charged with 200 parts by mass of deionized water, 0.03 parts by mass of tripotassium phosphate, 0.25 parts by mass of potassium dihydrogen phosphate, 0.002 parts by mass of disodium ethylenediaminetetraacetate (EDTA), 0.001 parts by mass of ferrous sulfate heptahydrate (FE), and 1.5 parts by mass of sodium dodecylbenzenesulfonate (SDS) as an emulsifier. Next, the charged raw materials were stirred while the gas inside the pressure-resistant polymerization reactor was replaced with nitrogen to thoroughly remove oxygen from the inside of the pressure-resistant polymerization reactor. Then, 100 parts by mass of butadiene (BD) was charged into the pressure-resistant polymerization reactor, and the temperature inside the pressure-resistant polymerization reactor was raised to 45°C. Next, 0.015 parts by mass of paramenthane hydroperoxide (PHP) was charged into the pressure-resistant polymerization reactor, followed by 0.04 parts by mass of sodium formaldehyde sulfoxylate (SFS), to initiate polymerization. Ten hours after the start of polymerization, the polymerization was terminated by removing the remaining monomers that were not used in the polymerization by volatilization under reduced pressure. During the polymerization, PHP, EDTA, and FE were each added to the pressure-resistant polymerization reactor in desired amounts and at desired times. This polymerization procedure yielded a latex (R-1) containing a core layer (polybutadiene rubber particles) primarily composed of polybutadiene rubber. The volume-average particle diameter of the polybutadiene rubber particles contained in the obtained latex was 0.10 μm.

[0186] Production Example 1-2: Preparation of polybutadiene rubber latex (R-2) 21 parts by mass of the polybutadiene rubber latex (R-1) obtained in Production Example 1-1 (containing 7 parts by mass of polybutadiene rubber particles), 200 parts by mass of deionized water, 0.03 parts by mass of tripotassium phosphate, 0.002 parts by mass of EDTA, and 0.001 parts by mass of FE were charged into a 100 L pressure-resistant polymerization reactor. Next, the gas inside the pressure-resistant polymerization reactor was replaced with nitrogen while stirring the charged raw materials, thereby thoroughly removing oxygen from inside the pressure-resistant polymerization reactor. 93 parts by mass of BD were then charged into the pressure-resistant polymerization reactor, and the temperature inside the pressure-resistant polymerization reactor was raised to 45°C. Next, 0.02 parts by mass of PHP was charged into the pressure-resistant polymerization reactor, followed by 0.10 parts by mass of SFS, to initiate polymerization. Thirty hours after the start of polymerization, the polymerization was terminated by devolatilization under reduced pressure to remove any remaining monomers not used in the polymerization. During the polymerization, PHP, EDTA, and FE were each added to the pressure-resistant polymerization reactor in desired amounts and at desired times. This polymerization procedure yielded a latex (R-2) containing a core layer (polybutadiene rubber particles) primarily composed of polybutadiene rubber. The volume-average particle diameter of the polybutadiene rubber particles contained in the resulting latex was 0.20 μm.

[0187] 2. Preparation of polymer particles (B) (formation of shell layer) Production Example 2-1: Preparation of aqueous latex (L-1) containing polymer particles (B) A glass reactor was charged with 262 parts by mass of the polybutadiene rubber latex (R-2) prepared in Production Example 1-2 (containing 87 parts by mass of polybutadiene rubber particles) and 57 parts by mass of deionized water. The glass reactor was equipped with a thermometer, a stirrer, a reflux condenser, a nitrogen inlet, and a monomer addition device. The gas in the glass reactor was replaced with nitrogen, and the charged raw materials were stirred at 60°C while the nitrogen replacement was being carried out. Next, 0.004 parts by mass of EDTA, 0.001 parts by mass of FE, and 0.2 parts by mass of SFS were added to the glass reactor. Subsequently, a mixture of shell layer-forming monomers (1 part by mass of methyl methacrylate (MMA), 6 parts by mass of styrene (ST), 2 parts by mass of acrylonitrile (AN), and 4 parts by mass of glycidyl methacrylate (GMA)) and 0.04 parts by mass of cumene hydroperoxide (CHP) was continuously added to the glass reactor over 120 minutes. After the addition was completed, 0.04 parts by mass of CHP was added to the glass reactor, and the mixture in the glass reactor was continuously stirred for an additional 2 hours to complete the polymerization. Through these operations, an aqueous latex (L-1) containing polymer particles (B) was obtained. The polymerization conversion rate of the monomer components was 99% or higher. The volume average particle diameter of the polymer particles (B) contained in the obtained aqueous latex (L-1) was 0.21 μm. The epoxy group content of the polymer particles (B) relative to the total amount of the shell layer was 2.2 mmol / g.

[0188] Production Example 2-2: Preparation of aqueous latex (L-2) containing polymer particles (B) An aqueous latex (L-2) containing polymer particles (B) was obtained in the same manner as in Production Example 2-1, except that 8 parts by mass of methyl acrylate (MA), 3.5 parts by mass of butyl acrylate (BA), and 1.5 parts by mass of GMA were used instead of 1 part by mass of MMA, 6 parts by mass of ST, 2 parts by mass of AN, and 4 parts by mass of GMA as the shell layer-forming monomers. The volume average particle diameter of the polymer particles (B) contained in the obtained aqueous latex (L-2) was 0.21 μm. The epoxy group content relative to the total mass of the shell layer of the polymer particles (B) was 0.8 mmol / g.

[0189] Production Example 2-3: Preparation of aqueous latex (L-3) containing polymer particles (B) A glass reactor was charged with 250 parts by mass of the polybutadiene rubber latex (R-1) prepared in Production Example 1-1 (containing 83 parts by mass of polybutadiene rubber particles) and 65 parts by mass of deionized water. The glass reactor was equipped with a thermometer, a stirrer, a reflux condenser, a nitrogen inlet, and a monomer addition device. The gas in the glass reactor was replaced with nitrogen, and the added raw materials were stirred at 60°C while the nitrogen replacement was being continued. Next, 0.004 parts by mass of EDTA, 0.001 parts by mass of FE, and 0.2 parts by mass of SFS were added to the glass reactor. Then, a mixture of shell layer-forming monomers (1 part by mass of MMA, 5 parts by mass of ST, 4 parts by mass of AN, and 7 parts by mass of GMA) and 0.08 parts by mass of CHP was continuously added to the glass reactor over 120 minutes. After the addition was completed, 0.12 parts by mass of CHP was added to the glass reactor, and the mixture in the glass reactor was stirred for an additional 2 hours to complete the polymerization. Through the above operations, an aqueous latex (L-3) containing polymer particles (B) was obtained. The polymerization conversion rate of the monomer components was 99% or more. The volume average particle diameter of the polymer particles (B) contained in the obtained aqueous latex (L-3) was 0.11 μm. The epoxy group content relative to the total amount of the shell layer of the polymer particles (B) was 2.9 mmol / g.

[0190] 3. Preparation of dispersion (M) in which polymer particles (B) are dispersed in epoxy resin (A) Production Example 3-1: Preparation of Dispersion (M-1) 132 g of methyl ethyl ketone (MEK) was introduced into a 1 L mixing tank at 25°C. Next, while stirring the MEK, 132 g of the aqueous latex (L-1) containing polymer particles (B) obtained in Production Example 2-1 (containing 40 g of polymer particles (B)) was added to the mixing tank. After the raw materials in the mixing tank were uniformly mixed, 200 g of water was added to the mixing tank at a feed rate of 80 g / min while stirring the raw materials in the mixing tank. After the water supply was completed, stirring was promptly stopped to obtain a slurry liquid consisting of aggregates containing polymer particles (B) and an aqueous phase containing a small amount of organic solvent. The aggregates were buoyant. Next, 360 g of the aqueous phase was discharged from the outlet at the bottom of the mixing tank, leaving a portion of the aggregates containing the aqueous phase in the mixing tank. 90 g of MEK was added to the obtained aggregates, and these were uniformly mixed to obtain a dispersion in which polymer particles (B) were uniformly dispersed in MEK. To the resulting dispersion, 60 g of the epoxy resin (A) A-1 (a bisphenol A-type epoxy resin that is liquid at room temperature) was added, and the mixture was mixed uniformly. MEK was removed from the resulting mixture using a rotary evaporator. In this way, a dispersion (M-1) in which polymer particles (B) were dispersed in epoxy resin (A) was obtained.

[0191] Production Example 3-2: Preparation of Dispersion (M-2) A dispersion (M-2) in which polymer particles (B) were dispersed in epoxy resin (A) was obtained in the same manner as in Production Example 3-1, except that (L-2) obtained in Production Example 2-2 was used instead of (L-1) as the aqueous latex containing polymer particles (B).

[0192] Production Example 3-3: Preparation of Dispersion (M-3) A dispersion (M-3) in which polymer particles (B) were dispersed in epoxy resin (A) was obtained in the same manner as in Production Example 3-1, except that (L-3) obtained in Production Example 2-3 was used instead of (L-1) as the aqueous latex containing polymer particles (B), and 80 g of epoxy resin (A-1) was used instead of 60 g of epoxy resin (A-1).

[0193] <Epoxy hardener (C)> C-1: Vegichem Green V140 (Tsukuno Foods, condensation product of dimer acid or fatty acid and polyamine, active hydrogen equivalent: 97g / eq) C-2: 4,4'-methylenebis(cyclohexylamine) (mixture of isomers) (Tokyo Chemical Industry Co., Ltd., active hydrogen equivalent: 52.6 g / eq) C-3: Hypro 1300X16 ATBN (manufactured by Huntsman, amine-terminated butadiene-acrylonitrile copolymer, molecular weight: approximately 3800, active hydrogen equivalent: 856 g / eq).

[0194] <Epoxy-based reactive diluent (D)> D-1: YED216M (Mitsubishi Chemical, 1,6-hexanediol diglycidyl ether) D-2: ERISYS GE-10 (Huntsman, o-cresyl glycidyl ether) D-3: Cardura E10P (Hexion, neodecanoic acid glycidyl ester) [Measurement and evaluation methods] The methods for measuring and evaluating the various physical properties measured in the examples and comparative examples are shown below.

[0195] [Volume average particle size measurement] The volume average particle diameter (Mv) of the polymer particles (B) dispersed in the aqueous latex was measured using a Microtrac UPA150 (manufactured by Nikkiso Co., Ltd.). The aqueous latex was diluted with deionized water and used as the measurement sample. The measurement was performed by inputting the refractive index of water and the refractive index of each polymer particle (B), adjusting the sample concentration so that the measurement time was 600 seconds, and the signal level was within the range of 0.6 to 0.8.

[0196] [Measurement of tensile properties (tensile test elongation and tensile modulus)] Each concrete coating composition obtained in the Examples and Comparative Examples was poured between two fluororesin-coated aluminum plates (25 cm × 25 cm × 0.5 cm) sandwiching a 3 mm-thick spacer. The compositions listed in Table 1 (Examples 1-2 and Comparative Examples 1-2) were cured at 23°C for 7 days, while the compositions listed in Table 2 (Examples 3-7 and Comparative Examples 3-4) were cured at 40°C for 66 hours to yield a 3 mm-thick plate-shaped coating film. The coating film was cut into a No. 1 dumbbell shape according to JIS K-7113 and subjected to a tensile test at 23°C at a pulling rate of 5 mm / min. The tensile test results were used to evaluate the tensile elongation (%) and tensile modulus (GPa) according to JIS K-7113. Since the coating films of the compositions of Comparative Examples 3 and 4 in Table 2 below were rubbery at room temperature, 3 mm thick plate-shaped coating films were cut into No. 1 dumbbell shapes in accordance with JIS K-6253, and tensile tests were performed at 23°C and a pulling speed of 500 mm / min in accordance with JIS K-6251. From the tensile test results, the tensile test elongation (%) and tensile modulus (GPa) were evaluated in accordance with JIS K-6251.

[0197] [Evaluation of crack tracking (zero span tension test)] In accordance with JSCE-K 532-2013, each concrete coating composition obtained in the Examples and Comparative Examples was applied to a thickness of 0.5 mm on the surface of a mortar substrate (40 x 120 x 8 mm) that had been cut in the center in advance. The coating was then cured at 23°C for 7 days. A zero-span tension test was conducted, with the coating pulled at a tensile speed of 5 mm / min. A coating elongation of 1 mm or more at break was rated "good," and one less than 1 mm was rated "unacceptable."

[0198] [Measurement of glass transition temperature and storage modulus by dynamic viscoelasticity measurement] Each concrete coating composition obtained in the Examples and Comparative Examples was cured under the same conditions as described above in "Measurement of Tensile Properties (Tensile Elongation and Tensile Modulus)" to obtain a 3 mm thick plate-shaped coating film. Each coating film was cut into a 40 mm long x 5 mm wide x 3 mm thick specimen. Dynamic viscoelasticity measurements were performed on the resulting specimens using an ITK DVA-200 dynamic viscoelasticity measuring device (manufactured by IT Measurement & Control Co., Ltd.). The specimens were heated at a rate of 8°C / min in tensile mode at a frequency of 1 Hz, and the temperature (°C) at which the loss tangent (tanδ) reached a maximum (glass transition temperature) and the storage modulus (GPa) at 23°C were measured.

[0199] [Measurement of total light transmittance] Each concrete coating composition obtained in the Examples and Comparative Examples was cured under the same conditions as described above in "Measurement of tensile properties (tensile test elongation and tensile modulus)" to obtain a 3 mm thick plate-shaped coating film. The total light transmittance (%) of the resulting cured plate was measured using a haze meter NDH4000 (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K-7361.

[0200] (Examples 1 to 7, Comparative Examples 1 to 4) Each component was weighed according to the formulation shown in Tables 1 and 2, and then thoroughly mixed to obtain a coating composition for concrete painting. The tensile properties (tensile test elongation and tensile modulus), crack followability (zero span tension test), glass transition temperature and storage modulus, and total light transmittance of the resulting coating composition for concrete painting were measured and evaluated according to the methods described above. The results are shown in Tables 1 and 2.

[0201] [Table 1]

[0202] [Table 2]

[0203] For Examples 1 to 7, it was found that a concrete coating composition containing an epoxy resin (A) and polymer particles (B) having a core-shell structure comprising a core layer and a shell layer, in which the content of polymer particles (B) is 1 to 100 parts by mass per 100 parts by mass of epoxy resin (A), and the content of solvent is 0 to 50% by mass per 100% by mass of the concrete coating composition, can suppress deterioration of coating film properties and has excellent crack followability.

[0204] In Comparative Examples 1 and 2, when the polymer particles (B) were not contained, there was still room for improvement in crack followability.

[0205] In Comparative Examples 3 and 4, when the polymer particles (B) were not contained and the main component was a dimer acid-modified epoxy resin described in JP-A-63-130676, the crack-following property was excellent, but the elastic modulus of the coating film was low, and there was room for improvement in the coating film properties. [Industrial Applicability]

[0206] According to one embodiment of the present invention, a coating composition for concrete coating can be provided that has excellent coating film properties and crack-following ability in concrete substrates. Therefore, one embodiment of the present invention can be used as a coating material for concrete coating and a filler for repairing cracks in concrete.

Claims

1. The composition contains an epoxy resin (A) and polymer particles (B) having a core-shell structure including a core layer and a shell layer, A coating composition for coating concrete, wherein the content of the polymer particles (B) is 1 part by mass to 100 parts by mass relative to 100 parts by mass of the epoxy resin (A), The coating composition for concrete does not contain a solvent, or contains more than 0 mass % but not more than 50 mass % of a solvent, based on 100 mass % of the coating composition for concrete.

2. The coating composition for coating concrete according to claim 1, wherein the coating composition for coating concrete does not contain the solvent.

3. 2. The coating composition for concrete coating according to claim 1, wherein the coating composition for concrete coating contains the solvent in an amount of more than 0 mass % and not more than 40 mass % based on 100 mass % of the coating composition for concrete coating.

4. 2. The coating composition for concrete coating according to claim 1, wherein the amount of the solvent emitted from the coating film formed by curing the coating composition for concrete coating is 50% by mass or less, based on 100% by mass of the coating composition for concrete coating.

5. A coating film obtained by curing the coating composition for concrete coating according to any one of claims 1 to 4.

6. The coating film according to claim 5, wherein the coating film has an average thickness of 0.1 mm or more.

7. 7. The coating of claim 5 or 6, wherein the coating is a clear coating.

8. A concrete structure having the coating film according to claim 5 on a concrete substrate.

9. The concrete structure according to claim 8, wherein the concrete structure is a flooring material.

10. The concrete structure according to claim 8, wherein the concrete structure is a bridge.

11. 2. The coating composition for concrete coating according to claim 1, wherein the epoxy resin (A) comprises at least one selected from the group consisting of bisphenol A epoxy resins, bisphenol F epoxy resins, and alicyclic epoxy resins.

12. 2. The coating composition for coating concrete according to claim 1, wherein the average epoxy equivalent of the epoxy resin (A) is 100 or more but less than 1,000.

13. 2. The coating composition for concrete coating according to claim 1, wherein the polymer particles (B) have a core layer made of one or more rubbers selected from the group consisting of diene-based rubbers, (meth)acrylate-based rubbers, and organosiloxane-based rubbers.

14. The coating composition for concrete further contains an epoxy curing agent (C), 2. The coating composition for coating concrete according to claim 1, wherein the content of the epoxy curing agent (C) is 1 part by mass to 200 parts by mass per 100 parts by mass of the epoxy resin (A).

15. The coating composition for concrete further contains an epoxy-based reactive diluent (D), 2. The coating composition for concrete coating according to claim 1, wherein the content of the epoxy-based reactive diluent (D) is 1.0 part by mass to 150.0 parts by mass relative to 100 parts by mass of the epoxy resin (A).

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