Method for manufacturing silicone acrylic graft copolymer resin

Abstract

The present invention provides a method for producing a silicone acrylic graft copolymer resin that yields a coating film with excellent resistance to repeated temperature changes. [Solution] The method for producing a silicone acrylic graft copolymer resin according to the present disclosure includes: step 1, synthesizing a water-dispersible acrylic resin by solvent polymerization in the presence of a polysiloxane to obtain a composite resin (i); step 2, adding 0.8 to 4 equivalents of water to 1 equivalent of the composite resin (i) to disperse the composite resin (i) in water; and step 3, synthesizing a hydrophobic acrylic resin by emulsion polymerization in the presence of the water-dispersed composite resin (i) to obtain a composite resin (ii).

Description

[Technical Field]

[0001] This invention relates to a method for producing silicone acrylic graft copolymer resin. [Background technology]

[0002] Conventionally, coating agents have been used to protect and enhance the aesthetic appeal of structures such as buildings, civil engineering structures, and vehicles. Furthermore, among the compositions that make up coating agents, there is a demand for water-based coating compositions (water-based coating compositions) that can be stably dispersed or dissolved (water-based) in an aqueous medium, from the viewpoint of environmental compatibility.

[0003] Among water-based coating compositions, those containing polysiloxane resins, such as those described in Patent Documents 1 to 3, are gaining popularity in the market due to their excellent weather resistance and minimal adverse effects on the human body and the environment, and are in high demand for various applications. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 07-196975 [Patent Document 2] Japanese Patent Publication No. 2002-97368 [Patent Document 3] Japanese Patent Publication No. 2005-187765 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, conventional polysiloxane resins provided by existing technologies had room for improvement in terms of the temperature resistance of coating films formed using aqueous coating compositions containing such polysiloxane resins. One aspect of the present invention aims to provide a method for producing a silicone acrylic graft copolymer resin that can obtain a coating film with excellent temperature resistance. [Means for solving the problem]

[0006] To solve the above problems, a method for producing a silicone acrylic graft copolymer resin according to one aspect of the present invention is: Step 1: A step to synthesize a water-dispersible acrylic resin by solvent polymerization in the presence of polysiloxane to obtain a composite resin (i); Step 2: Adding 0.8 to 4 equivalents of water to 1 equivalent of the composite resin (i) to disperse the composite resin (i) in water; and Step 3: A step to synthesize a hydrophobic acrylic resin by emulsion polymerization in the presence of the water-dispersed composite resin (i) to obtain composite resin (ii). Includes. [Effects of the Invention]

[0007] According to one aspect of the present invention, a method for producing a silicone acrylic graft copolymer resin that yields a coating film with excellent resistance to repeated temperature changes can be provided. [Modes for carrying out the invention]

[0008] One embodiment of the present invention will be described in detail below. Unless otherwise specified in this specification, "A to B" representing a numerical range means "greater than or equal to A and less than or equal to B".

[0009] [1. Method for producing silicone acrylic graft copolymer resin] A method for producing a silicone acrylic graft copolymer resin according to one embodiment of the present invention is: Step 1: A step to synthesize a water-dispersible acrylic resin by solvent polymerization in the presence of polysiloxane to obtain a composite resin (i); Step 2: adding 0.8 to 4 equivalents of water to 1 equivalent of the composite resin (i) and dispersing the composite resin (i) in water; and Step 3: synthesizing a hydrophobic acrylic resin by emulsion polymerization in the presence of the water-dispersed composite resin (i) to obtain a composite resin (ii) which includes.

[0010] Since the silicone acrylic graft copolymer resin has a siloxane bond with high bond energy in the main chain, high weather resistance can be expected when it is used as a resin for paints. Also, the silicone acrylic graft copolymer resin has an acrylic resin with organic properties grafted onto a polysiloxane with inorganic properties, so it exhibits a balanced property between the hardness due to polysiloxane and the softness due to the acrylic resin.

[0011] However, in the prior art, there was room for improvement from the perspective of the temperature cycle resistance of the coating film obtained from an aqueous coating composition containing a silicone acrylic graft copolymer resin. In this specification, the temperature cycle resistance means the durability of the coating film when temperature and cold stimuli are repeated, and includes, for example, frost resistance. The inventors have found that by first graft-polymerizing a water-dispersible acrylic resin onto a polysiloxane and then graft-polymerizing a hydrophobic acrylic resin, a silicone acrylic graft copolymer resin capable of obtaining a coating film with improved temperature cycle resistance can be provided.

[0012] In this specification, the acrylic resin means a resin having a structural unit derived from an acrylic monomer as a main component, and the acrylic resin preferably contains 50 to 100% by weight of the structural unit derived from the acrylic monomer, more preferably 70 to 100% by weight, and even more preferably 90 to 100% by weight. The acrylic resin may be a resin consisting only of the structural unit derived from the acrylic monomer.

[0013] The determination of whether an acrylic resin is water-dispersible or hydrophobic can be made based on the TOC (Total Organic Carbon) value, in accordance with the solubility test in water specified in the polymer flow scheme of the Act on Examination and Regulation of Manufacture, etc. of Chemical Substances (Chemical Substances Control Law). Specifically, in this specification, water-dispersible acrylic resin means an acrylic resin whose TOC value in water is 1 mg / L or more, and hydrophobic acrylic resin means an acrylic resin whose TOC value in water is less than 1 mg / L.

[0014] Composite resin (i) refers to a resin in which a water-dispersible acrylic resin is grafted onto polysiloxane. Composite resin (ii) refers to a resin in which a hydrophobic acrylic resin is further grafted onto composite resin (i), that is, a resin in which both a water-dispersible acrylic resin and a hydrophobic acrylic resin are grafted onto polysiloxane. Both composite resin (i) and composite resin (ii) are silicone acrylic graft copolymer resins, but it has been found that composite resin (ii) in particular can improve the temperature resistance of the coating film.

[0015] In silicone acrylic graft copolymer resins, structural units corresponding to polysiloxane are also called polysiloxane units, structural units corresponding to water-dispersible acrylic resin are also called water-dispersible acrylic resin units, and structural units corresponding to hydrophobic acrylic resin are also called hydrophobic acrylic resin units. Polysiloxane units are structural units derived from polysiloxane, water-dispersible acrylic resin units are structural units derived from solvent polymerization in step 1, and hydrophobic acrylic resin units are structural units derived from emulsion polymerization in step 3.

[0016] The silicone acrylic graft copolymer resin obtained by the above manufacturing method can be used in a dissolved or dispersed state in an aqueous medium that has minimal adverse effects on the human body and the environment. Therefore, it can contribute to achieving Sustainable Development Goals (SDGs), such as Goal 12, "Ensure sustainable consumption and production patterns."

[0017] <Process 1> Step 1 is a step of synthesizing a water-dispersible acrylic resin by solvent polymerization in the presence of a polysiloxane to obtain a composite resin (i). In other words, Step 1 is a step of obtaining a composite resin (i) containing polysiloxane units and water-dispersible acrylic resin units by subjecting an acrylic monomer to solvent polymerization in the presence of a polysiloxane. A polysiloxane is a polymer of a silane compound and is also referred to as a polyorganosiloxane. That is, a polysiloxane contains structural units derived from a silane compound.

[0018] As the silane compound, a silane compound (A) having a radically polymerizable unsaturated group and a hydrolyzable silyl group, and optionally, a silane compound (B) having a hydrolyzable silyl group and not having a radically polymerizable unsaturated group may be included. As the silane compound, one kind may be used alone or two or more kinds may be used in combination.

[0019] The silane compound (A) having a radically polymerizable unsaturated group and a hydrolyzable silyl group is preferably a silane compound represented by the following general formula (I): R 1 a R 2 b -Si-(OR 3 ) 4-a-b ···(I) In the formula, each R 1 is independently a substituted alkyl group having 1 to 10 carbon atoms, an alkenyl group, or an aryl group having a radically polymerizable unsaturated group and optionally having other substituents, each R 2 is independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group, each R 3 is independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, a is an integer of 1 to 3, b is an integer of 0 to 2, and a + b is an integer of 1 to 3.

[0020] Examples of the radically polymerizable unsaturated group include a (meth)acryloyl group, a (meth)acrylamide group, and the like. R 1Examples of silane compounds (A) in which is a substituted alkyl group having a radically polymerizable unsaturated group include (meth)acryloxymethyltrimethoxysilane, (meth)acryloxymethylmethyldimethoxysilane, (meth)acryloxymethyldimethylmethoxysilane, (meth)acryloxymethyltriethoxysilane, (meth)acryloxymethylmethyldiethoxysilane, (meth)acryloxymethyldimethylethoxysilane, 2-(meth)acryloxyethyltrimethoxysilane, 2-(meth)acryloxyethylmethyldimethoxysilane, 2-(meth)acryloxyethyldimethylmethoxysilane, 2-(meth)acryloxyethyltriethoxysilane, 2-(meth)acryloxyethylmethyldiethoxysilane, 2-(meth)acryloxyethyldimethylethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropylmethyldimethoxysilane, γ-(meth)acryloxypropyldimethylmethoxysilane, γ-(meth)acryloxypropyltriethoxysilane, γ-(meth)acryloxypropylmethyldiethoxysilane, γ -(meth)acryloxypropyldimethylethoxysilane, 4-(meth)acryloxybutyltrimethoxysilane, 4-(meth)acryloxybutylmethyldimethoxysilane, 4-(meth)acryloxybutyldimethylmethoxysilane, 4-(meth)acryloxybutyltriethoxysilane, 4-(meth)acryloxybutylmethyldiethoxysilane, 4-(meth)acryloxybutyldimethylethoxysilane, 5-(meth)acryloxypentyltrimethoxysilane, 5-(meth)acryloxypentylmethyldimethoxysilane, 5-( meth)acryloxypentyldimethylmethoxysilane, 5-(meth)acryloxypentyltriethoxysilane, 5-(meth)acryloxypentylmethyldiethoxysilane, 5-(meth)acryloxypentyldimethylethoxysilane, 6-(meth)acryloxyhexyltrimethoxysilane, 6-(meth)acryloxyhexylmethyldimethoxysilane, 6-(meth)acryloxyhexyldimethylmethoxysilane, 6-(meth)acryloxyhexyltriethoxysilane, 6-(meth)acryloxyhexylmethyldiethoxysilane,Examples include 6-(meth)acryloxyhexyldimethylethoxysilane.

[0021] R 1 Examples of silane compounds (A) in which the group is an alkenyl group include vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, and vinyldimethylethoxysilane.

[0022] R 1 Examples of silane compounds (A) in which the aryl group has a radically polymerizable unsaturated group and may optionally have other substituents include p-styryltrimethoxysilane, p-styrylmethyldimethoxysilane, p-styryldimethylmethoxysilane, p-styryltriethoxysilane, p-styrylmethyldiethoxysilane, and p-styryldimethylethoxysilane.

[0023] Among these, R is the most versatile. 1 As such, (meth)acryloyl group-substituted alkyl groups or alkenyl groups are preferred.

[0024] R 2 Examples of alkyl groups in this context include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, amyl group, isoamyl group, hexyl group, cyclohexyl group, cyclohexylmethyl group, cyclohexylethyl group, heptyl group, isoheptyl group, n-octyl group, isooctyl group, 2-ethylhexyl group, etc. 2 Examples of aryl groups in this context include phenyl, naphthyl, and benzyl groups. 2 When a is 1 and b is 1, it is preferable that it is a methyl group.

[0025] R 3Examples of alkyl groups in this context include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, pentyl group, hexyl group, amyl group, isoamyl group, hexyl group, cyclohexyl group, cyclohexylmethyl group, cyclohexylethyl group, heptyl group, isoheptyl group, octyl group, n-octyl group, isooctyl group, 2-ethylhexyl group, nonyl group, decyl group, and the like.

[0026] In general formula (I), R 3 The fact that it is a hydrogen atom means that a hydroxyl group exists on the silicon atom. The group formed by the bonding of a hydroxyl group to a silicon atom is also called a silanol group. 3 Being an alkyl group means that an alkoxy group is bonded to a silicon atom. A group formed by the bond of an alkoxy group to a silicon atom is also called an alkoxysilyl group. Alkoxy groups are hydrolyzable groups. When an alkoxysilyl group is hydrolyzed, it becomes a silanol group. For convenience, in this specification, these silanol groups and alkoxysilyl groups are collectively referred to as hydrolyzable silyl groups. Among the above hydrolyzable silyl groups, alkoxysilyl groups are preferred because the alcohol produced as a by-product by hydrolysis is easily removed.

[0027] From the viewpoint of easily condensing silane compound (A) with other silane compounds that do not have radical polymerizable unsaturated groups (silane compound (B)), the R in general formula (I) 2 and R 3 The number of carbon atoms in the alkyl group is preferably 1 to 3, and most preferably 1.

[0028] The silane compound (B) having a hydrolyzable silyl group and lacking a radically polymerizable unsaturated group is preferably a silane compound represented by the following general formula (II): R 4 n -Si-(OR 5 ) 4-n ...(II) In the formula, R 4Each of these is independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group, and R 5 Each of these is independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and n is an integer from 0 to 3.

[0029] R 4 Examples of alkyl groups in this context include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, amyl group, isoamyl group, hexyl group, cyclohexyl group, cyclohexylmethyl group, cyclohexylethyl group, heptyl group, isoheptyl group, n-octyl group, isooctyl group, 2-ethylhexyl group, etc. 4 Examples of aryl groups in this context include phenyl, naphthyl, and benzyl groups.

[0030] R 5 Examples of alkyl groups in this context include methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, nonyl, and decyl groups.

[0031] Specific compounds represented by general formula (II) include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltriisopropoxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltriisopropoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, hexyltriisopropoxysilane, octyltrimethoxysilane, octyltriethoxysilane, octyltriisopropoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriisopropoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane, diphenyldimethoxysilane, trimethylmonomethoxysilane, triphenylmonomethoxysilane, and the like.

[0032] As silane compound (B), a silane compound other than the compound represented by general formula (II) that has a hydrolyzable silyl group and does not have a radically polymerizable unsaturated group (silane compound (B1)) can also be used. Examples of such silane compound (B1) include compounds having a hydrolyzable silyl group and a mercapto group, such as γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropylmethyldimethoxysilane.

[0033] Compounds containing hydrolyzable silyl groups and mercapto groups (sometimes referred to as mercaptosilanes) have a chain transfer effect and can therefore function as graft sites during polymerization (graft polymerization) between polysiloxane units and water-dispersible acrylic resin units.

[0034] The silane compound is preferably a silane compound having three hydrolyzable groups. This increases the degree of condensation of the polysiloxane, and from this viewpoint as well, improves the resistance to repeated temperature changes.

[0035] Furthermore, because the polysiloxane contains structural units derived from silane compounds having three hydrolyzable groups, it is possible to easily make the polysiloxane water-based compared to cases where only silane compounds having two or fewer hydrolyzable groups are included. This action allows for a reduction in the proportion of hydrophilic components after coating film formation, thereby improving the water resistance of the coating film.

[0036] As for silane compounds having three hydrolyzable groups, in the above general formula (I), R 3 Each of these is an alkyl group having 1 to 10 carbon atoms, and 4-ab is 3, that is, a is 1 and b is 0, a silane compound (sometimes called silane compound (A')), and in the above general formula (II), R 5Examples include silane compounds (sometimes referred to as silane compounds (B')) in which each of the atoms is an alkyl group having 1 to 10 carbon atoms, and 4-n is 3, i.e., n is 1.

[0037] In step 1, a water-dispersible acrylic resin is synthesized in the presence of polysiloxane. This involves grafting the water-dispersible acrylic resin onto the polysiloxane. For the synthesis of the water-dispersible acrylic resin, an acrylic monomer (C) that does not have hydrolyzable silyl groups, which will serve as the structural unit of the water-dispersible acrylic resin, is used.

[0038] In this specification, an acrylic monomer is a monomer containing a radically polymerizable unsaturated group of acrylic, specifically a (meth)acryloyl group or a (meth)acrylamide group. Monomers having a hydrolyzable silyl group in addition to the above-mentioned radically polymerizable unsaturated group of acrylic are classified as silane compounds (A) and are therefore not considered acrylic monomers (C). Furthermore, in this specification, the (meth)acryloyl group encompasses both the acryloyl group and the methacryloyl group, and the (meth)acrylamide group encompasses both the acrylamide group and the methacrylamide group.

[0039] Examples of acrylic monomers (C) include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, tert-butyl (meth)acrylate, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, isobornyl (meth)acrylate, etc.; nitrile group-containing radical polymerizable monomers such as (meth)acrylonitrile; and glycerides. Examples include epoxy group-containing radical polymerizable monomers such as sidyl (meth)acrylate; hydroxyl group-containing radical polymerizable monomers such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate; monomers having two or more polymerizable unsaturated bonds such as ethylene glycol di(meth)acrylate and allyl (meth)acrylate; and fluorine-containing radical polymerizable monomers such as trifluoro(meth)acrylate, pentafluoro(meth)acrylate, perfluorocyclohexyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl methacrylate, and β-(perfluorooctyl)ethyl (meth)acrylate.

[0040] Furthermore, as the acrylic monomer (C), a monomer having a salt structure consisting of an acid and a base and an acrylic radical polymerizable unsaturated group, but without a hydrolyzable silyl group, soluble in water, and not forming micelles in water may be used. This monomer is also referred to as monomer (C1) in this specification.

[0041] In this specification, "salt structure" refers to the structure of a neutral salt obtained by neutralizing an acid and a base. Here, the acid used for neutralization may be a strong acid or a weak acid. Similarly, the base used for neutralization may be a strong base or a weak base.

[0042] Specific salt structures include, for example, the neutral salt structure of a strong acid and a strong base, such as sodium sulfonate, potassium sulfonate, calcium sulfonate, sodium nitrate, potassium nitrate, and calcium nitrate; the neutral salt structure of a strong acid and a weak base, such as ammonium sulfonate and ammonium nitrate; the neutral salt structure of a weak acid and a strong base, such as sodium acetate, potassium acetate, calcium acetate, sodium phosphate, potassium phosphate, and calcium phosphate; and the neutral salt structure of a weak acid and a weak base, such as ammonium acetate and ammonium phosphate. Preferably, the salt structure of the monomer (C1) is sodium sulfonate.

[0043] In this specification, "water soluble" means that when an aqueous solution is prepared by adding 1 g of the monomer to 10 g of water at 25°C, stirring it thoroughly, letting it stand for one week under conditions of 25°C, and observing its appearance visually, no precipitate, dispersion, or separation of layers is observed in the aqueous solution, and it is transparent.

[0044] In this specification, "micelle" refers to an aggregate formed by the association of amphiphilic molecules through hydrophobic interactions. Here, an amphiphilic molecule is defined as a molecule having both a hydrophobic group and a hydrophilic group within it. Therefore, a "structure capable of forming micelles in water" refers to a structure having both a hydrophobic group and a hydrophilic group within it.

[0045] To determine whether a monomer is capable of forming micelles in water, follow these steps: Add 1 g of the monomer to a two-layer solution containing 10 g of water and 2 g of butyl acetate. Stir thoroughly, then let stand for 12 hours. If a uniform turbidity is observed, the monomer is considered capable of forming micelles in water. If, after 12 hours, clear layers of water and butyl acetate separate, the monomer is considered not capable of forming micelles in water (i.e., micelle formation is impossible).

[0046] Examples of monomers (C1) include sodium sulfoethyl methacrylate, sodium 2-(methacryloyloxy)ethanesulfonate, sodium acrylamide-t butylsulfonate, potassium 2-(methacryloyloxy)ethanesulfonate, potassium acrylamide-t butylsulfonate, calcium 2-(methacryloyloxy)ethanesulfonate, calcium acrylamide-t butylsulfonate, ammonium sulfoethyl methacrylate, ammonium 2-(methacryloyloxy)ethanesulfonate, ammonium acrylamide-t butylsulfonate, sodium acrylate, potassium acrylate, calcium acrylate, ammonium acrylate, sodium methacrylate, potassium methacrylate, calcium methacrylate, and ammonium methacrylate.

[0047] Furthermore, monomers (C1) can be obtained commercially. Examples of such commercially available products include "Antox MS-2N-D" manufactured by Nippon Emulsifier Co., Ltd., "ATBS-Na" manufactured by Toagosei Co., Ltd., and "Sodium Acrylate" and "Potassium Acrylate" manufactured by Asada Chemical Industries, Ltd.

[0048] The monomer (C1) content in 100% by weight of the total acrylic monomer (C) added in step 1 is preferably 1% by weight or more, more preferably 2% by weight or more, and even more preferably 4% by weight or more. Having a monomer (C1) content within the above range improves the solubility or dispersibility of the composite resin (i) in water. Furthermore, the upper limit of the monomer (C1) content is not particularly limited, but may be, for example, 20% by weight or less, or 10% by weight or less.

[0049] Furthermore, as the acrylic monomer (C), a monomer having an acrylic radical polymerizable unsaturated group, lacking a hydrolyzable silyl group, and capable of forming micelles in water may be used. This monomer is also referred to as monomer (C2) in this specification. Monomer (C2) may be an amphiphilic molecule having an acrylic radical polymerizable unsaturated group and lacking a hydrolyzable silyl group.

[0050] The hydrophobic group within the monomer (C2) is not particularly limited, but examples include alkyl groups with 3 or more carbon atoms having acrylic radical polymerizable unsaturated groups, aryl groups, etc. The hydrophilic group within the monomer (C2) is not particularly limited, but examples include anionic hydrophilic groups such as sulfonates, carboxylates, and sulfate esters, cationic hydrophilic groups such as amine salts and quaternary ammonium salts, amphoteric hydrophilic groups such as betaine, and nonionic hydrophilic groups such as polyoxyalkylene.

[0051] From the viewpoint of versatility, the monomer (C2) preferably has a polyoxyalkylene structure. Examples of monomers (C2) having a polyoxyalkylene structure include polyoxyethylene and polyoxypropylene. The monomer (C2) preferably has a polyoxyalkylene structure having 1 to 100 repeating oxyalkylene units, more preferably has a polyoxyalkylene structure having 2 to 50 units, and even more preferably has a polyoxyalkylene structure having 5 to 20 units.

[0052] Examples of monomers (C2) include ADEKA Corporation's Adekaria Soap SR-05, SR-10, SR-20, SR-1025, SR-2025, SR-3025, SR-10S, NE-10, NE-20, NE-30, NE-40, SE-10, SE-20, ER-10, ER-20, ER-30, ER-40, Nippon Emulsifier Co., Ltd.'s Antox-MS-60, RMA-1120, RMA-564, RMA-568, RMA-506, MA-30, MA-50, MA-100, MA-150, RMA-1120, MPG130-MA, MPG-130MA, RMA-150M, RMA-300M, RMA-450M, RA-1020, RA-1820, Aqualon KH-05, KH-10, RN-20, RN-30, RN-50, RN-2025, HS-10, HS-20, HS-1025, BC05, BC10, BC0515, BC1025 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Eleminor JS-2, JS-20, RS-30 (manufactured by Sanyo Chemical Industries, Ltd.), Latemul S-180, S-180 (manufactured by Kao Corporation) A, PD-104, PD-420, PD-430, NOF Corporation Blenmar PE-90, PE-200, PE-350, AE-90, AE-200, AE-350, PP-500, PP-800, PP-1000, AP-400, AP-550, A P-800, 700PEP-350B, 10PEP-550B, 55PET-400, 30PET-800, 55PET-800, 30PPT-800, 50PPT-800, 70PPT-800, PME-100, PME-200, PME-40 Examples include 0, PME-1000, PME-4000, AME-400, 50POEP-800B, 50AOEP-800B, AEP, AET, APT, PLE, ALE, PSE, ASE, PKE, AKE, PNE, ANE, PNP, ANP, PNEP-600, Light Ester 130MA, 041MA, MTG, Light Acrylate EC-A, MTG-A, 130A, DPM-A, P-200A, NP-4EA, NP-8EA, EHDG-A (manufactured by Kyoeisha Chemical Co., Ltd.), and NK-ESTER M-20G, M-40G, M-90G, M-230G, AMP-10G, AMP-20G, AMP-60G, AM-90G, and LA (manufactured by Shin Nakamura Chemical Industry Co., Ltd.). From the viewpoint of versatility and micelle stability, Adekarya Soap SR-10 is preferred.

[0053] The monomer (C2) content in the total amount of acrylic monomer (C) added in step 1 is preferably 1% by weight or more, more preferably 3% by weight or more, and even more preferably 5% by weight or more. Having the monomer (C2) content within the above range facilitates viscosity adjustment when the composite resin (i) is aqueous-based. Furthermore, there is no particular upper limit to the monomer (C2) content; for example, it may be 20% by weight or less, or 10% by weight or less.

[0054] In step 1, it is preferable to adjust the composition of the acrylic monomer (C) used so that the synthesized structural units satisfy the definition of a water-dispersible acrylic resin described above. Specifically, it is preferable that the content of monomers having hydroxyl groups, as well as monomer (C1) and monomer (C2), among the acrylic monomer (C) of acrylic monomer (C) is 40% by weight or more out of 100% by weight of the total amount of acrylic monomer (C).

[0055] The solvent polymerization described above is a radical polymerization, and is preferably carried out in the presence of an initiator and a water-soluble organic solvent. By using a water-soluble organic solvent, the radical polymerization of polysiloxane and monomer (C) can be suitably carried out.

[0056] The initiator is a radical polymerization initiator. The initiator is not particularly limited as long as it is a substance capable of initiating a radical polymerization reaction between the radically polymerizable unsaturated group derived from the silane compound (A) and the monomer (C).

[0057] Examples of initiators include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), tert-butyl peroxypivalate, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, di-tert-butyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, and diisopropyl peroxycarbonate.

[0058] The amount of initiator is preferably 0.01 to 10% by weight, more preferably 0.05 to 7% by weight, and even more preferably 0.1 to 5% by weight, based on 100% by weight of the total amount of composite resin (i). When the amount of initiator is 0.01% by weight or more, polymerization proceeds smoothly. Also, when the amount of initiator is 10% by weight or less, it is easier to obtain a polymer with an appropriate molecular weight.

[0059] Examples of water-soluble organic solvents include methanol, ethanol, 2-propanol, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, polyethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, diethylene glycol monoisobutyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, and ethylene glycol diethyl ether. Among these, alcohol-based solvents such as methanol, ethanol, and 2-propanol are particularly preferred, considering the possibility of volatilization during film formation.

[0060] (Physical properties of composite resin (i)) • Structural unit ratio The structural unit ratio in the composite resin (i), i.e., the weight ratio of polysiloxane units to water-dispersible acrylic resin units, is preferably 5:95 to 70:30, more preferably 20:80 to 60:40, and even more preferably 30:70 to 60:40. When the structural unit ratio is within the above range, advantages include improved dispersion stability when the composite resin (i) is aqueous-based, and the provision of a coating film with excellent water resistance. The structural unit ratio can be calculated based on the amount of each monomer charged, minus the weight of the generated volatile components and the weight of the unreacted monomers.

[0061] • Glass transition temperature (Tg) of water-dispersible acrylic resin units The Tg of the water-dispersible acrylic resin units in the composite resin (i) is not particularly limited, but is preferably 40°C or lower, more preferably 30°C or lower, and even more preferably 20°C or lower, as this allows for the provision of a coating film with superior resistance to repeated temperature changes. The lower limit of the Tg of the water-dispersible acrylic resin units is not particularly limited, but is, for example, -10°C or higher, may be -7°C or higher, or -5°C or higher. In this specification, the Tg of the water-dispersible acrylic resin units refers to the value obtained by Fox's formula (TG Fox, Bull. Am. Phys. Soc. 1, 123 (1956)).

[0062] <Process 1-1> The above-mentioned manufacturing method may include step 1-1, which involves synthesizing the polysiloxane by polymerization of a silane compound, prior to step 1. For example, the polysiloxane can be obtained by condensing the above-mentioned silane compound in the presence of water and a condensation catalyst.

[0063] The weight ratio of the vinyl-group-containing silane compound to the total amount of the silane compound is preferably 0.02 to 0.08, and more preferably 0.03 to 0.08. If the weight ratio of the vinyl-group-containing silane compound is within the above range, the water-dispersible acrylic resin can be sufficiently grafted onto the polysiloxane in step 1, and as a result, a composite resin (i) that can be stably dispersed or dissolved (water-based) in an aqueous medium can be obtained. Furthermore, the water resistance and temperature resistance of the resulting coating film can be further improved.

[0064] The weight ratio of the silane compound having three hydrolyzable groups to the total amount of the silane compound is preferably 0.70 or higher, preferably 0.80 or higher, and preferably 0.90 or higher. If the weight ratio of the silane compound having three hydrolyzable groups is within the above range, the water resistance and temperature resistance of the resulting coating film can be further improved. The weight ratio of the silane compound having three hydrolyzable groups may be 1.00 or lower, 0.98 or lower, or 0.95 or lower. Most preferably, the weight ratio of the silane compound having three hydrolyzable groups is 1.00, that is, only the silane compound having three hydrolyzable groups is used as the silane compound.

[0065] Examples of condensation catalysts include acidic catalysts, basic catalysts, and neutral catalysts. From the viewpoint of ease of use, acidic or neutral catalysts are preferred. One type of condensation catalyst may be used alone, or two or more types may be used in combination.

[0066] As an acidic catalyst, organic acids are preferred due to their compatibility with silane compounds, and phosphate esters or carboxylic acids can be suitably used. Examples of organic acids include ethyl acid phosphate, butyl acid phosphate, dibutyl pyrophosphate, butoxyethyl acid phosphate, 2-ethylhexyl acid phosphate, isotridecyl acid phosphate, dibutyl phosphate, bis(2-ethylhexyl) phosphate, formic acid, acetic acid, butyric acid, isobutyric acid, and the like.

[0067] As a basic catalyst, organic bases are preferred due to their compatibility with silane compounds and diluent solvents, and amine compounds can be suitably used. Examples of organic bases include triethylamine, diazabicycloundecene, and 1,4-diazabicyclo[2.2.2]octane.

[0068] Examples of neutral catalysts include neutral salts. By using a neutral salt as a catalyst, a polysiloxane with an appropriate degree of condensation can be obtained, resulting in an aqueous coating composition with excellent storage stability.

[0069] In this specification, "neutral salt" means a normal salt consisting of an acid and a base. While there are no particular limitations on neutral salts, salts consisting of a cation selected from the group consisting of Group 1 element ions, Group 2 element ions, tetraalkylammonium ions, and guanidium (guanidinium) ions, and an anion selected from the group consisting of Group 17 element ions (excluding fluoride ions), sulfate ions, nitrate ions, and perchlorate ions are preferred.

[0070] Considering availability and safety during handling, lithium chloride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, magnesium chloride, calcium chloride, strontium chloride, lithium bromide, sodium bromide, potassium bromide, rubidium bromide, cesium bromide, magnesium bromide, calcium bromide, strontium bromide, lithium iodide, sodium iodide, potassium iodide, rubidium iodide, cesium iodide, magnesium iodide, calcium iodide, strontium iodide, tetrabutylammonium chloride, tetrabutylammonium bromide, and tetrabutylammonium iodide are particularly preferred as neutral salts.

[0071] The amount of condensation catalyst is preferably 0.1 ppm to 50,000 ppm, more preferably 1 ppm to 10,000 ppm, even more preferably 5 ppm to 1,000 ppm, and particularly preferably 10 ppm to 500 ppm, relative to the total amount of silane compounds. When the amount of condensation catalyst is 0.1 ppm or more, it acts appropriately as a catalyst. Furthermore, when the amount of condensation catalyst is 50,000 ppm or less, it has effects such as suppressing the rapid progress of the reaction and the associated heat generation, and suppressing the decrease in water resistance due to residual salt.

[0072] In step 1-1, water is further used. This water is also called "condensation water." The amount of condensation water in step 1-1 may be 0.9 equivalents or more, 1.0 equivalent or more, or 1.1 equivalents or more, relative to the total number of hydroxyl groups and / or hydrolyzable groups bonded to the silicon atoms in the silane compound. Furthermore, the amount of condensation water in step 1-1 is preferably 3.0 equivalents or less, more preferably 2.5 equivalents or less, even more preferably 2.0 equivalents or less, and particularly preferably 1.5 equivalents or less, relative to the total number of hydroxyl groups and / or hydrolyzable groups bonded to the silicon atoms in the silane compound.

[0073] If the amount of condensation water is 0.9 equivalents or more, the hydrolysis and dehydration condensation of the silane compound can proceed, increasing the degree of condensation and improving resistance to repeated temperature changes and water resistance. If the amount of condensation water is 3.0 equivalents or less, it is possible to prevent the degree of condensation from becoming excessively high and to suppress the progression of gelation during synthesis.

[0074] In step 1-1, organic solvents are generated as a result of dehydration condensation and hydrolysis. Examples of organic solvents generated in step 1-1 include methanol, ethanol, and 2-propanol.

[0075] <Process 2> Step 2 is a step in which 0.8 to 4 equivalents of water are added to 1 equivalent of the composite resin (i) to disperse the composite resin (i) in water. The medium after the completion of Step 1 may contain the organic solvent generated in Step 1-1 and the organic solvent added in Step 1. In Step 2, this medium is converted into a medium mainly composed of water (diluted with water), thereby atomizing the composite resin (i). That is, an emulsion containing the composite resin (i) is obtained.

[0076] As described above, the amount of water added in step 2 is 0.8 to 4 equivalents per equivalent of composite resin (i), preferably 1 to 3 equivalents, and more preferably 1 to 2 equivalents. If the amount of water is 0.8 equivalents or more, uniformly dispersed particles are easily obtained. If the amount of water is 4 equivalents or less, the concentration of the emulsion containing the composite resin (i) does not become too low, and the reaction in step 3 can be carried out suitably. In addition, the time required to remove water when manufacturing paint can be shortened.

[0077] Furthermore, before carrying out emulsion polymerization in the following step 3, solvents other than water (organic solvents such as alcohol generated in step 1-1, and / or other organic solvents contained therein) may be removed by vacuum defloration. Preferably, 80% or more of these solvents other than water are removed, more preferably 90% or more by weight, and particularly preferably 95% or more by weight. Emulsion polymerization proceeds more easily when the content of solvents other than water is low. If there are too many solvents other than water, emulsion polymerization may not proceed, or the dispersion stability of the composite resin (i) dispersed in the resulting water may be disrupted, causing the particles to aggregate.

[0078] <Process 3> Step 3 is a step of synthesizing a hydrophobic acrylic resin by emulsion polymerization in the presence of the water-dispersed composite resin (i) to obtain a composite resin (ii). In other words, Step 3 is a step of obtaining a composite resin (ii) containing polysiloxane units, water-dispersible acrylic resin units, and hydrophobic acrylic resin units by emulsion polymerization of an acrylic monomer (and optionally a monomer other than an acrylic monomer) in the presence of the water-dispersed composite resin (i).

[0079] The acrylic monomers that form the structural units of the hydrophobic acrylic resin may include the acrylic monomers newly added in step 3 and the acrylic monomers remaining unreacted in steps 1 and 2. Other monomers besides acrylic monomers may include the silane compound (A), silane compound (B), and / or other copolymerizable monomers described later.

[0080] The content of monomer (C) in 100% by weight of the total monomers constituting the hydrophobic acrylic resin is not particularly limited, but is preferably 50% by weight or more, more preferably 70% by weight or more, even more preferably 80% by weight or more, particularly preferably 90% by weight or more, and most preferably 95% by weight or more. By including monomer (C) within the above range, emulsion polymerization can be carried out stably, and hydrophobic acrylic resin can be stably provided. Furthermore, the upper limit of the monomer (C) content is not particularly limited, but may be, for example, 10% by weight or less, or 5% by weight or less.

[0081] The monomer (C2) can be used as a reactive emulsifier in emulsion polymerization because it provides a site for polymerization reactions and pre-emulsifies monomer components. In particular, hydrophobic acrylic resins polymerized in the presence of the reactive emulsifier monomer (C2) may have better water resistance compared to those polymerized in the presence of a non-reactive emulsifier.

[0082] When monomer (C2) is used, the content of monomer (C2) in 100% by weight of the total amount of monomers constituting the hydrophobic acrylic resin is preferably 1% by weight or more, and more preferably 1.5% by weight or more. By including monomer (C2) within the above range, it is possible to stably obtain a hydrophobic acrylic resin with excellent water resistance by emulsion polymerization. Furthermore, there is no particular upper limit to the monomer (C2) content, but for example, it may be 10% by weight or less, or 5% by weight or less.

[0083] When using silane compound (A), the content of silane compound (A) in 100% by weight of the total amount of monomers constituting the hydrophobic acrylic resin is preferably 0.5 to 20% by weight, more preferably 1 to 15% by weight, even more preferably 1.5 to 10% by weight, and particularly preferably 2 to 8% by weight. Including silane compound (A) within the above range has the advantage of providing a coating film that is both water-resistant and flexible, and has superior resistance to repeated temperature changes.

[0084] When using silane compound (B), the content of silane compound (B) in 100% by weight of the total amount of monomers constituting the hydrophobic acrylic resin is preferably 0.1 to 5% by weight, more preferably 0.1 to 3% by weight, and even more preferably 0.2 to 1% by weight. In particular, the inclusion of structural units derived from mercaptosilane within the above range can further improve the temperature resistance of the coating film.

[0085] Other copolymerizable monomers include, for example, aromatic hydrocarbon vinyl monomers such as styrene, α-methylstyrene, chlorostyrene, 4-hydroxystyrene, and vinyltoluene; vinyl esters or allyl compounds such as vinyl acetate, vinyl propionate, vinyl versatate, and diallyl phthalate; nitrile group-containing vinyl monomers such as (meth)acrylonitrile; vinyl methyl ether; propylene; and butadiene. Among these, styrene is preferred because it can provide a coating film with high gloss and excellent appearance.

[0086] When using other copolymerizable monomers, the content of the other copolymerizable monomers in 100% by weight of the total amount of monomers constituting the hydrophobic acrylic resin is preferably 0.5 to 20% by weight, more preferably 1 to 15% by weight, even more preferably 1.5 to 10% by weight, and particularly preferably 2 to 8% by weight. By including the other monomers within the above range, the effects of incorporating the other monomers (in the case of styrene, improved appearance) can be suitably exhibited.

[0087] In step 3, it is preferable to adjust the composition of the monomers used so that the synthesized structural units satisfy the definition of hydrophobic acrylic resin described above. Specifically, it is preferable that the content of monomers having hydroxyl groups among the acrylic monomer (C) is 10% by weight or less, and the content of monomer (C1) and monomer (C2) is less than 5% by weight, out of 100% by weight of the total amount of monomers constituting the hydrophobic acrylic resin.

[0088] In the emulsion polymerization described above, it is preferable to use a polymerization catalyst. As the polymerization catalyst, the initiators listed in Step 1 can be used. Furthermore, when using oxidizing agents such as tert-butyl peroxypivalate, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, di-tert-butyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, and diisopropyl peroxycarbonate from among the initiators listed in Step 1, a reducing agent may also be used in addition to these oxidizing agents. Examples of reducing agents include sodium sulfite, sodium thiosulfite, sodium hydroxymethanesulfinate, ascorbic acid, sodium ascorbate, Longalit, Bruggolite® FF-6, and thiourea dioxide.

[0089] (Physical properties of composite resin (ii)) • Structural unit ratio The structural unit ratio in composite resin (ii), i.e., the weight ratio of composite resin (i) units to hydrophobic acrylic resin units, is preferably 50:50 to 85:15, and more preferably 50:50 to 80:20. The composite resin (i) units refer to the sum of the aforementioned siloxane units and water-dispersible acrylic resin units. When the structural unit ratio is within the above range, there are advantages such as improved dispersion stability when composite resin (ii) is aqueous-based and the provision of a coating film with excellent water resistance. The structural unit ratio can be calculated based on the amount of each monomer charged, minus the weight of the generated volatile components and the weight of the unreacted monomers.

[0090] ·Weight average molecular weight The weight-average molecular weight of composite resin (ii) is not particularly limited, but is preferably 30,000 to 300,000, as this allows for the provision of a coating film with superior temperature and cold resistance. It may also be 40,000 to 300,000, 50,000 to 300,000, 70,000 to 270,000, or 100,000 to 250,000. In this specification, the weight-average molecular weight of composite resin (ii) can be calculated in polystyrene equivalent by measuring it using, for example, a high-speed GPC instrument HLC-8320GPC manufactured by Tosoh Corporation, with columns of TSKgel superH5000, TSKgel superH4000, TSKgel superH3000, or TSKgel guardcolumn SuperH-L, mobile phase of THF (tetrahydrofuran), measurement temperature of 40°C, and flow rate of 0.6 mL / min.

[0091] [2. Applications of silicone acrylic graft copolymer resin] The silicone acrylic graft copolymer resin, i.e., composite resin (ii), obtained by the above manufacturing method can be used as an aqueous coating composition. The aqueous coating composition comprises at least the composite resin (ii) and water. In this specification, an aqueous coating composition means a coating composition that uses water as a medium. A coating composition that uses water as a medium means a coating composition that contains 5% by weight or more of water in 100% by weight of the coating composition.

[0092] The water content in an aqueous coating composition is not particularly limited as long as it is 5% by weight or more of the aqueous coating composition by 100% by weight. However, it is preferable that the water content be 10% by weight or more, more preferably 20% by weight or more, and particularly preferable that it be 50% by weight or more, as this can further improve the workability of the aqueous coating composition. Furthermore, there is no particular upper limit to the water content in an aqueous coating composition; for example, it may be 90% by weight or less, or 80% by weight or less.

[0093] Furthermore, in this specification, "coating composition" means a composition that can form a coating film when applied to the surface of an object to be coated, and that the coating film can provide protection from scratches and dirt, as well as impart an aesthetic appearance.

[0094] The water-based coating composition may contain additives commonly used in the art (particularly in the field of paints) to the extent that it achieves the effects of the present invention. Examples of such additives include pigments, fillers, plasticizers, film-forming aids, wetting agents, dispersants, thickeners, defoaming agents, preservatives, antioxidants, anti-settling agents, leveling agents, UV absorbers, antistatic agents, antifreeze agents, antibacterial agents, antifungal and anti-algal agents, tackifiers, rust inhibitors, hydrophilic agents, and the like. The composition may contain only one type of additive, or two or more types. Furthermore, the amount of these additives can be appropriately determined by those skilled in the art depending on the intended use.

[0095] A water-based coating composition can be applied to any substrate and cured to provide a coating film with excellent resistance to repeated temperature changes. In other words, in one embodiment of the present invention, a coating film obtained by curing a water-based coating composition, and a laminate comprising the coating film obtained by curing a water-based coating composition and a substrate are provided.

[0096] The method for applying the water-based coating composition to the substrate is not particularly limited. For example, it may be applied using brushes, rollers, air sprays, airless sprays, etc., commonly used in general painting. It can also be applied using methods such as reverse coating, gravure coating, bar coating, die coating, spray coating, kiss coating, wire bar coating, and curtain coating. Any known method can be used to cure the water-based coating composition applied to the substrate.

[0097] Water-based coating compositions are suitably used, for example, as water-based coating compositions for building interiors and exteriors, for automotive applications such as metallic bases or clear coatings on metallic bases, for direct coating of metals such as aluminum, stainless steel, and silver, for direct coating of ceramic materials such as slate, concrete, tiles, mortar, gypsum board, asbestos slate, asbestos board, precast concrete, lightweight aerated concrete, calcium silicate board, tiles, and bricks, for glass, and for stone materials such as natural marble and granite.

[0098] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0099] One embodiment of the present invention may include the following configuration: <1> Step 1: A step to synthesize a water-dispersible acrylic resin by solvent polymerization in the presence of polysiloxane to obtain a composite resin (i); Step 2: Adding 0.8 to 4 equivalents of water to 1 equivalent of the composite resin (i) to disperse the composite resin (i) in water; and Step 3: A step to synthesize a hydrophobic acrylic resin by emulsion polymerization in the presence of the water-dispersed composite resin (i) to obtain composite resin (ii). A method for producing a silicone acrylic graft copolymer resin, including [the specified element]. <2> The process includes step 1-1, in which the polysiloxane is synthesized by polymerization of a silane compound, wherein the weight ratio of the vinyl group-containing silane compound to the total amount of the silane compound is 0.02 to 0.08. <1> The manufacturing method described above. <3> The silane compound is a silane compound having three hydrolyzable groups. <2> The manufacturing method described above. <4> In the composite resin (i), the weight ratio of polysiloxane units to water-dispersible acrylic resin units is 30:70 to 60:40. <1> ~ <3> A manufacturing method described in any one of the following. <5> In the composite resin (ii), the weight ratio of composite resin (i) units to hydrophobic acrylic resin units is 50:50 to 85:15. <1> ~ <4> A manufacturing method described in any one of the following. [Examples]

[0100] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0101] 〔material〕 <Composite resin (i)> (Polysiloxane units) • Silane compound (A) Vinyltrimethoxysilane (abbreviated as "Vi-TMS"): "A-171" manufactured by Momentive Performance Materials Japan LLC. • Silane compound (B) Methyltrimethoxysilane (abbreviated as "M-TMS"): "OFS-6070" manufactured by Dow Toray Ltd. Phenyltrimethoxysilane (abbreviated as "Ph-TMS"): "Z-6124" manufactured by Dow Toray Industries, Inc. • Condensed water pure water • Condensation catalyst Dibutyl phosphate (abbreviated as "DBP"): "DBP" manufactured by Johoku Chemical Industry Co., Ltd. (Water-dispersible acrylic resin units) • Monomer (C) Methyl methacrylate (abbreviated as "MMA"): Manufactured by Mitsubishi Gas Chemical Company, Inc. Butyl acrylate (abbreviated as "BA"): Manufactured by Nippon Shokubai Co., Ltd. 2-Hydroxyethyl methacrylate (abbreviated as "HEMA"): Manufactured by Nippon Shokubai Co., Ltd. • Monomer (C1) Acrylamide-t-butylsulfonate sodium (abbreviated as "ATBS"): "ATBS-Na" manufactured by Toagosei Co., Ltd. • Monomer (C2) Ether sulfate type ammonium salt (abbreviated as "SR-10"): "Adekaria Soap SR-10" manufactured by ADEKA Corporation, commercially classified as "reactive anionic emulsifier", compound represented by the following formula (A):

[0102] [ka]

[0103] • Radical polymerization initiator 2,2'-Azobis(2,4-dimethylvaleronitrile) (abbreviated as "V65"): "V-65" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. (Hydrophobic acrylic resin units) • Monomer γ-Methacryloxypropyltrimethoxysilane (3-(trimethoxysilyl)propyl methacrylate, abbreviated as "TSMA"): "A-174" manufactured by Momentive Performance Materials Japan LLC. Methyl methacrylate (abbreviated as "MMA"): Manufactured by Mitsubishi Chemical Corporation. Butyl acrylate (abbreviated as "BA"): Manufactured by Nippon Shokubai Co., Ltd. Cyclohexyl methacrylate (abbreviated as "CHMA"): Manufactured by Mitsubishi Gas Chemical Company, Inc. • Polymerization catalyst Bruggolite® FF-6 (abbreviated as "FF-6") manufactured by Bruggemann Chemical. t-butyl hydroperoxide (abbreviated as "P-4") manufactured by NOF Corporation. Furthermore, unreacted monomers from step 1 can also be incorporated into hydrophobic acrylic resin units.

[0104] <Acrylic resin emulsion> (Resin components) • Monomer (C) Butyl acrylate (abbreviated as "BA"): Manufactured by Nippon Shokubai Co., Ltd. Methyl methacrylate (abbreviated as "MMA"): Manufactured by Mitsubishi Chemical Corporation. Butyl methacrylate (abbreviated as "BMA"): Manufactured by Mitsubishi Chemical Corporation Glycidyl methacrylate (abbreviated as "GMA"): Manufactured by Fujifilm Wako Pure Chemical Corporation 2-Hydroxyethyl methacrylate (abbreviated as "HEMA"): Manufactured by Nippon Shokubai Co., Ltd. Polyethylene glycol monomethacrylate: Bremmer PE-200 manufactured by NOF Corporation • Monomer (C2) (reactive emulsifier) ER-20 (75%): A diluted solution containing 75% by weight of monomer components of "Adeka Soap ER-20" manufactured by ADEKA Corporation. Ether sulfate type ammonium salt (abbreviated as "SR-1025 (25%)"): A diluted solution containing 25% by weight of ether sulfate type ammonium salt (monomer component) from "ADEKA Soap SR-1025" manufactured by ADEKA Corporation. • Silane compound (A) γ-Methacryloxypropylmethyldimethoxysilane (abbreviated as "Z6033"): "Z-6033" manufactured by Dow Toray Industries, Inc. γ-Methacryloxypropyltriethoxysilane (abbreviated as "Y9936"): "Y-9936" manufactured by Momentive Performance Materials Japan LLC. Other monomers Styrene (abbreviated as "St"): Manufactured by Kishida Chemical Co., Ltd. <Other ingredients> (water) pure water (Antifreezing agent) Propylene glycol: Manufactured by Fujifilm Wako Pure Chemical Corporation (Humectant) "Dispex Ultra FA 4437" manufactured by BASF Japan Ltd. (Dispersant) Cray Valley's "SMA1440H Solution" "Disperbyk-2090" manufactured by Big Chemie Japan Co., Ltd. (Pigment) "PFC105" manufactured by Ishihara Sangyo Co., Ltd. (Preservative) "Slout 99N" manufactured by Nippon Enviro-Chemicals Co., Ltd. (Antifoaming agent) Acrylic defoaming agent: "Agitan295" manufactured by MUNZING CHEMIE. (Film-forming aid) 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate: "CS-12" manufactured by JNC Corporation (Thickening agent) "SN Thickener 612NC" manufactured by Sunopco Co., Ltd. (Anti-mold and anti-algal agent) "Monicide AZ" manufactured by Nippon Enviro-Chemicals Co., Ltd. [Measurement and evaluation methods] Measurements and evaluations in the examples and comparative examples were performed using the following methods.

[0105] (Tg of water-dispersible acrylic resin units) The Tg of the water-dispersible acrylic resin unit was calculated using Fox's formula.

[0106] (Water resistance test) The aqueous coating compositions prepared in Examples 1-6 and Comparative Examples 1-3 were applied to the float glass substrate using a 6 mil applicator, and then cured for one week in a constant temperature room at 23°C and 50% relative humidity. 0.5 mL of pure water was dropped onto the resulting laminate consisting of the substrate and coating film, and the appearance of the coating film was visually observed after 24 hours. The water resistance of the coating film was evaluated based on the following criteria. A: No change in appearance. B: The area where pure water was dropped has swollen, shrunk, and changed color.

[0107] In this specification, a water-based coating composition capable of providing a coating film that receives an A rating or higher in the above evaluation is evaluated as being capable of providing a coating film with excellent water resistance.

[0108] (Temperature resistance test) A water-based cationic sealer (manufactured by Nippon Paint Co., Ltd.) was applied as a primer to the slate board substrate, and then DAN Filler Epoxy (manufactured by Nippon Paint Co., Ltd.) was applied as an intermediate coat using a textured roller. Finally, a water-based coating composition was spray-applied and cured for one week in a constant temperature room at 23°C and 50% relative humidity. The resulting laminate consisting of the substrate and coating film was immersed in water set at 23°C for 18 hours, then left to stand in air set at -20°C for 4 hours, and then left to stand in air set at 50°C for 2 hours. This 24-hour operation constituted one cycle, and the appearance of the coating film was observed visually to evaluate the temperature resistance of the coating film based on the following criteria. A: After 5 cycles, there is no peeling or detachment of the coating, nor any abnormalities such as cracking. B: After 3 cycles, there are no abnormalities in the coating, and after 5 cycles, there is no peeling or detachment of the coating, but there are a few small cracks of about 1 cm in size. C: After 1 cycle, there were no abnormalities in the coating, and after 3 cycles, there was no peeling or detachment of the coating, but small cracks of about 1 cm were scattered across the entire surface of the coating, and the cracks were not connected. D: After 1 cycle, there were no abnormalities in the coating, but after 3 cycles, peeling or detachment of the coating occurred in some areas, cracks were present across the entire coating, and each crack was connected. E: After one cycle, peeling or detachment of the coating occurs, cracks are present across the entire coating, and each crack is connected.

[0109] In this specification, a water-based coating composition capable of providing a coating film that receives a rating of C or higher in the above evaluation is evaluated as being capable of providing a coating film with excellent resistance to repeated temperature changes.

[0110] [Synthesis Example 1] <Preparation of composite resin (i)> (Step 1-1: Synthesis of polysiloxane units) In a reactor equipped with a stirrer, thermometer, and reflux condenser, 39.9 parts by weight of the monomers M-TMS, 33.8 parts by weight of Ph-TMS, 4.8 parts by weight of Vi-TMS, 24.1 parts by weight of pure water, and 0.023 parts by weight of the condensation catalyst DBP were charged. The reaction was carried out at a reaction temperature of 68°C for 3 hours with stirring to obtain polyorganosiloxane, which is a polysiloxane unit. The amounts of monomers (M-TMS, Ph-TMS, Vi-TMS) in Table 1 represent the amount of each monomer charged in the synthesis of the polysiloxane unit. The amount of polysiloxane unit was calculated based on the amount of each monomer charged minus the weight of volatile components generated by the hydrolysis reaction.

[0111] (Step 1: Polymerization of water-dispersible acrylic resin units and Step 2: Water dispersion) To the reactor containing the aforementioned polysiloxane units, a mixed solution of 8.1 parts by weight of monomer MMA, 23.5 parts by weight of BA, 2.4 parts by weight of ATBS, 6.0 parts by weight of SR-10, and 0.20 parts by weight of the radical polymerization initiator V-65 was added dropwise from a dropping funnel at a constant rate over 3 hours. Next, a mixed solution of 0.14 parts by weight of the radical polymerization initiator V-65 and 8.3 parts by weight of methanol was added dropwise at a constant rate over 0.5 hours. After the dropwise addition, the mixture was stirred at 75°C for 2 hours, and then diluted with water to obtain a composition containing composite resin (i) and water. The ratio of polysiloxane units to water-dispersible acrylic resin units (structural unit ratio), solids content (SC), ATBS residual rate, etc. in the obtained composite resin (i) are shown in Table 1.

[0112] [Synthesis Examples 2 to 5] A composition containing composite resin (i) and water was obtained using the same method as in Synthesis Example 1, except that the types and amounts of each component were changed as shown in Table 1. The ratio of polysiloxane units to water-dispersible acrylic resin units in the obtained composite resin (i), as well as the solids content, ATBS residual rate, etc., are shown in Table 1.

[0113] [Table 1]

[0114] In Table 1, "Vi-TMS ratio" refers to the Vi-TMS content (by weight) in the total amount of silane compound. "Equivalent number" of condensed water refers to the number of equivalents relative to the total number of hydrolyzable groups in the silane compound in step 1-1. "%" refers to "weight percent". ATBS residual rate refers to the ratio of the amount of ATBS remaining unpolymerized at the end of step 1 (before dilution with water) to the amount of ATBS charged. ATBS amount (g) refers to the amount of ATBS remaining unpolymerized at the end of step 1 (before dilution with water). ATBS content refers to the proportion of ATBS contained in the total amount of the composition including the obtained composite resin (i). "Multiple" in media conversion refers to the number of equivalents of water added per equivalent of composite resin (i) in step 2. Structural unit ratio was calculated based on the amount of polysiloxane units calculated as described above. Other values ​​in Table 1 where units or definitions are not shown refer to parts by weight. The same applies to the following tables.

[0115] [Synthesis example A] 262.2 parts by weight of the composition obtained in Synthesis Example 1 was charged into a reactor equipped with a stirrer, thermometer, and reflux condenser. In the monomer tank, a mixture of 0.28 parts by weight of TSMA, 16.73 parts by weight of MMA, and 39.7 parts by weight of BA was prepared. The contents of the monomer tank were gradually added to the reactor using a pump over 3 hours. Simultaneously with the start of the pump, 8.45 parts by weight of FF-6 adjusted to a 2% aqueous solution and 0.28 parts by weight of P-4 adjusted to a 7% aqueous solution were added. After another 30 minutes, 0.28 parts by weight of P-4 adjusted to a 7% aqueous solution was added, and after another 30 minutes, 0.28 parts by weight of P-4 adjusted to a 7% aqueous solution was added, and after another 30 minutes, 1.98 parts by weight of FF-6 adjusted to a 2% aqueous solution was added, and the mixture was stirred for a further 30 minutes. This yielded a composition containing a composite resin (ii) obtained by emulsion polymerization of a hydrophobic acrylic resin in the presence of a composite resin (i), and water.

[0116] [Synthesis examples B to F] A composition containing a composite resin (ii) and water was obtained by emulsion polymerization of a hydrophobic acrylic resin in the presence of composite resin (i) using the same method as in Synthesis Example A, except that the types and amounts of each component were changed as shown in Table 2.

[0117] [Table 2]

[0118] In Table 2, the ATBS retention rate refers to the ratio of the amount of ATBS remaining unpolymerized at the end of Step 3 to the amount of ATBS charged in Step 1. The ATBS retention amount (g) refers to the amount of ATBS remaining unpolymerized at the end of Step 3. The ATBS content refers to the proportion of ATBS contained in the total amount of the composition containing the obtained composite resin (ii). The structural unit ratio refers to the ratio of polysiloxane units, water-dispersible acrylic resin units, and hydrophobic acrylic resin units in the composite resin (ii).

[0119] [Synthesis example G] <Synthesis of acrylic resin emulsion> (Synthesis of core components) In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen gas inlet tube, and dropping funnel, 39 parts by weight of deionized water, 0.16 parts by weight of Adekarya soap SR-1025, and 0.25 parts by weight of 5% sodium bicarbonate aqueous solution were charged, and the temperature was raised to 50°C while introducing nitrogen gas. After raising the temperature, 0.5 parts by weight of P-4 prepared as a 7% aqueous solution, 0.35 parts by weight of FF-6 prepared as a 10% aqueous solution, and 0.7 parts by weight of a mixed aqueous solution of ferrous sulfate heptahydrate (0.10%) / ethylenediaminetetraacetate disodium (0.40%) were added. Next, the first monomer emulsion was added to the above reaction system at a constant rate over 120 minutes. The first monomer emulsion was obtained by emulsifying a mixture of 18.2 parts by weight of BA, 1.2 parts by weight of Z-6033, and 5.2 parts by weight of St as the core formulation, with 0.7 parts by weight of ER-20, 0.9 parts by weight of SR-1025, and 9 parts by weight of deionized water. During the addition of the first monomer emulsion, 0.25 parts by weight of P-4, prepared as a 7% aqueous solution, and 0.4 parts by weight of FF-6, prepared as a 2.5% aqueous solution, were added in two separate additions. After the addition of the first monomer emulsion was completed, the polymerization reaction was carried out for 1 hour. During the polymerization reaction, 0.1 parts by weight of P-4, prepared as a 7% aqueous solution, and 0.15 parts by weight of FF-6, prepared as a 2.5% aqueous solution, were added to the reaction system. The core component of the acrylic resin emulsion was obtained by this procedure.

[0120] (Synthesis of shell components) To the reaction system containing the above core components, 0.25 parts by weight of P-4, prepared as a 7% aqueous solution, and 0.5 parts by weight of FF-6, prepared as a 2.5% aqueous solution, were added. Next, the second monomer emulsion was added to the above reaction system at a constant rate over 300 minutes. The second monomer emulsion was obtained by emulsifying a mixture of 5.4 parts by weight of MMA, 59.0 parts by weight of BMA, 1.6 parts by weight of GMA, 1.6 parts by weight of HEMA, 1.8 parts by weight of PE-200, 1.2 parts by weight of Y-9936, and 2.0 parts by weight of St as a shell formulation, by adding 1.1 parts by weight of ER-20, 5.3 parts by weight of SR-1025, and 24.05 parts by weight of deionized water. During the addition of the second monomer emulsion, 1.0 part by weight of P-4, prepared as a 7% aqueous solution, and 1.4 parts by weight of FF-6, prepared as a 2.5% aqueous solution, were added in six separate additions. After the addition of the second monomer emulsion was completed, the polymerization reaction was carried out for 1.5 hours. During the polymerization reaction, 0.10 parts by weight of P-4, which had been prepared as a 7% aqueous solution, and 0.15 parts by weight of FF-6, which had been prepared as a 2.5% aqueous solution, were added to the reaction system. This procedure yielded the shell component of the acrylic resin emulsion. To the emulsion containing the synthetic resin consisting of the obtained core component and shell component, 3.5 parts by weight of a 5% sodium bicarbonate aqueous solution was added, and then the solid content was adjusted to 50% with deionized water to obtain an acrylic resin emulsion.

[0121] [Table 3]

[0122] In Table 3, "Content of monomers having hydrolyzable silyl groups" refers to the ratio of structural units derived from silane compound (A) in 100% by weight of the resin components of the obtained acrylic resin emulsion.

[0123] [Example 1] A mill base was prepared by blending the types and amounts of each component shown in the "Mill Base" column of Table 4. A water-based coating composition was then prepared by mixing the obtained mill base with the types and amounts of various synthesized resins and other components shown in the "Cutback" column of Table 4. The water resistance and temperature / collapse resistance of the obtained water-based coating composition were evaluated. The results are shown in Table 4. In Table 4, the unit for each component amount is "parts by weight," and the resins used in the blending were devolved under reduced pressure to adjust the solid content to 50% before blending.

[0124] [Examples 2-6, Comparative Examples 1-3] A water-based coating composition was prepared using the same method as in Example 1, except that the types and amounts of each component were changed as shown in Table 4 or 5. The water resistance and temperature resistance of the obtained water-based coating composition were evaluated. The results are shown in Table 4 or 5.

[0125] [Table 4]

[0126] [Table 5]

[0127] In Tables 4 and 5, the structural unit ratios refer to the ratio of polysiloxane units to water-dispersible acrylic resin units and hydrophobic acrylic resin units in composite resin (ii), except in Comparative Example 3, where it refers to the ratio of polysiloxane units to water-dispersible acrylic resin units and acrylic resin emulsion in composite resin (ii). The residual ATBS amount (g) refers to the amount of ATBS remaining in the aqueous coating composition without polymerization.

[0128] As shown in Tables 4 and 5, Examples 1 to 6, which used an aqueous coating composition containing a composite resin (ii) comprising polysiloxane units, water-dispersible acrylic resin units, and hydrophobic acrylic resin units, exhibited superior temperature and cold cycle resistance compared to Comparative Examples 1 to 3, which used an aqueous coating composition containing a composite resin (i) that lacked hydrophobic acrylic resin units. Although an acrylic resin emulsion was added to Comparative Example 3, its temperature and cold cycle resistance was still inferior to that of Examples 1 to 6. Regarding water resistance, Examples 1 to 6 were equivalent to those of Comparative Examples 1 to 3. [Industrial applicability]

[0129] One aspect of the present invention can be used in various fields such as water-based paints and coatings.

Claims

1. Step 1: A step of synthesizing a water-dispersible acrylic resin by solvent polymerization in the presence of polysiloxane to obtain a composite resin (i); Step 2: Adding 0.8 to 4 equivalents of water to 1 equivalent of the composite resin (i) to disperse the composite resin (i) in water; and Step 3: A step to synthesize a hydrophobic acrylic resin by emulsion polymerization in the presence of the water-dispersed composite resin (i) to obtain composite resin (ii). A method for producing a silicone acrylic graft copolymer resin, including [the specified element].

2. Prior to step 1, step 1-1 is performed to synthesize the polysiloxane by polymerization of a silane compound. The manufacturing method according to claim 1, wherein the weight ratio of the vinyl group-containing silane compound to the total amount of the silane compound is 0.02 to 0.

08.

3. The method for producing the product according to claim 2, wherein the silane compound is a silane compound having three hydrolyzable groups.

4. The manufacturing method according to any one of claims 1 to 3, wherein the weight ratio of polysiloxane units to water-dispersible acrylic resin units in the composite resin (i) is 30:70 to 60:

40.

5. The manufacturing method according to any one of claims 1 to 3, wherein the weight ratio of composite resin (i) units to hydrophobic acrylic resin units in the composite resin (ii) is 50:50 to 85:15.

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