Water-based resin composition

Abstract

To provide an aqueous resin composition enabling formation of a coated film which is homogeneous when coated, and finally has a hydrophobic surface.SOLUTION: An aqueous resin composition is provided which includes a composite resin (A) and an aqueous medium (B), and in which the composite resin (A) includes a vinyl polymer (A1) and an urethane resin (A2), and a difference (Tg(A2)-Tg(A1)) between a glass transition temperature Tg(A2) of the urethane resin (A2) and a glass transition temperature Tg(A1) of the vinyl polymer (A1) is -40°C or higher and 140°C or lower.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an aqueous resin composition.

Background Art

[0002] Aqueous resin compositions are used in a variety of applications such as paper coating / impregnation, fibers / non-woven fabrics, carpets, civil engineering building materials, mortar cement, automotive parts, tire cords, paints, pastes, rust preventive coatings, adhesives, plastic modification, cosmetic puffs, electronic materials, adhesives (general, for rubber), coating / impregnation (non-woven fabric / paper), fiber impregnation / reinforcing fiber processing (carpets, etc.), moisture-proof / water-resistant coatings, cement / mortar, building material processing / wood adhesion, synthetic leather, artificial leather, gloves, contraceptives, ink acceptors, ink dispersants, etc.

[0003] For the aqueous resin composition, various characteristics are required depending on the application, and aqueous resin compositions combining different resins have been proposed. For example, Patent Document 1 describes an aqueous resin containing a block copolymer composed of a vinyl polymer segment and a polyurethane segment having an acid group neutralized with an acid group and / or a basic compound. Further, Patent Document 2 describes a composition containing a latex obtained by seed-polymerizing a diene-based unsaturated monomer in the presence of seed latex and an aqueous polyurethane. Patent Document 3 describes a resin composition containing a hydrogenated derivative of a hydroxyl group-containing conjugated diene polymer and another aqueous resin in the same micelle.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the case of the above composite resin, during coating, although the coatability and penetrability to a (hydrophilic) substrate are good, in the end, the surface of the coating film may be required to be hydrophobic. However, conventionally known composite resins mainly aim to homogeneously mix different resins at the molecular level and form a coating film in such a homogeneous mixed state, and means for forming the above coating film are not known. The present invention has been made in view of the above problems, and an object thereof is to provide an aqueous resin composition capable of forming a coating film that is homogeneous during coating but finally has a hydrophobic surface.

Means for Solving the Problems

[0006] The present inventors have found that in an aqueous resin composition containing a composite resin, by setting the type and glass transition temperature of the resin used in the composite resin within a specific range, it is possible to form an initially homogeneous coating film while segregating the resin by heating and finally form a coating film having a hydrophobic surface.

[0007] That is, the aqueous resin composition of the present invention contains a composite resin (A) and an aqueous medium (B), and the composite resin (A) contains a vinyl polymer (A1) and a urethane resin (A2), and the difference (Tg(A2) - Tg(A1)) between the glass transition temperature Tg(A2) of the urethane resin (A2) and the glass transition temperature Tg(A1) of the vinyl polymer (A1) is -40°C or higher and 120°C or lower.

Advantages of the Invention

[0008] By using the aqueous resin composition of the present invention, it is possible to form a coating film that is initially homogeneous but finally has a hydrophobic surface.

Modes for Carrying Out the Invention

[0009] The aqueous resin composition of the present invention contains a composite resin (A) and an aqueous medium (B). The composite resin includes a vinyl polymer (A1) and a urethane resin (A2).

[0010] The vinyl polymer (A1) represents a polymer having units derived from a vinyl monomer (a). The vinyl monomer (a) represents a compound having at least one polymerizable vinyl bond in one molecule. As the vinyl monomer (a), one kind or two or more kinds can be used, and examples include conjugated diene compounds (a1) and other vinyl compounds (a2).

[0011] As the diene compound (a1), one kind or two or more kinds can be used, and examples include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 1,3-heptadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, 3-methyl-1,3-pentadiene, 2-chloro-1,3-butadiene, and the like.

[0012] The content of the conjugated diene compound (a1) is preferably 1% by mass or more, more preferably 10% by mass or more, still more preferably 30% by mass or more in the total amount of the vinyl monomer (a), and the upper limit is 100% by mass.

[0013] As the other vinyl compound (a2), one or more thereof can be used. For example, alkyl (meth)acrylates having 4 to 22 carbon atoms such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, 3-methylbutyl (meth)acrylate, neopentyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, hexadecyl (meth)acrylate; Cycloalkyl (meth)acrylates having 6 to 20 carbon atoms such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate; Allyl (meth)acrylates such as phenyl (meth)acrylate; Aralkyl (meth)acrylates having 10 to 20 carbon atoms such as benzyl (meth)acrylate, phenethyl (meth)acrylate; Allyloxyalkyl (meth)acrylates such as phenoxyethyl (meth)acrylate; Alkyl crotonates such as methyl crotonate, ethyl crotonate; Unsaturated dicarboxylic acid alkyl esters such as dimethyl maleate, dibutyl maleate, dimethyl fumarate, dibutyl fumarate, dimethyl itaconate, dibutyl itaconate; Aromatic vinyl monomers such as styrene, p-tert-butylstyrene, α-methylstyrene, vinyltoluene, vinylpyridine, chlorostyrene, chloromethylstyrene; (Meth)acrylonitrile, crotononitrile, (meth)acrylamide, N-methyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methoxyethyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl(meth)acrylamide, N,N-diethylaminoethyl (meth)acrylate, N,N-diethylaminopropyl (meth)acrylate, N-(meth)acryloylmorpholine, N-(meth)acryloylpyrrolidine, N-vinylformamide, N-vinylpyrrolidone, N-vinylimidazole, N-vinylcarbazole, N-vinylquinoline, N-vinylpiperidine and other nitrogen atom-containing monomers (preferably monosubstituted or disubstituted (meth)acrylamides (including those in which the substituents are bonded to form a ring)) and methyl chloride salts of the nitrogen atom-containing monomers; Vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, vinyl chloride, vinylidene chloride and other halogenated olefins; ethylene, propylene, isobutylene, 1-butene and other α-olefins; Vinyl acetate, vinyl propionate, vinyl pivalate, vinyl versatate, vinyl benzoate, vinyl neodecanoate and other vinyl carboxylates; Methyl vinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether and other alkyl vinyl ethers; cyclohexyl vinyl ether and other cycloalkyl vinyl ethers; Acrolein, methyl vinyl ketone and other carbonyl group-containing monomers; Polyoxyethylene group-containing (meth)acrylic monomers such as polyethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, polyethylene glycol polypropylene glycol copolymer (meth)acrylate, methoxypolyethylene glycol polypropylene glycol copolymer (meth)acrylate, polyethylene glycol polytetramethylene glycol copolymer (meth)acrylate, methoxypolyethylene glycol polytetramethylene glycol copolymer (meth)acrylate; Fluoroalkyl group-containing monomers such as perfluorocyclohexyl (meth)acrylate, di-perfluorocyclohexyl fumarate, N-isopropyl fluoro octane sulfonic acid amide ethyl (meth)acrylate; Unsaturated dicarboxylic acid anhydrides such as maleic anhydride, citraconic anhydride, mesaconic anhydride, itaconic anhydride, tetrahydrophthalic anhydride; Cyclic ether-containing monomers such as glycidyl (meth)acrylate, allyl glycidyl ether, tetrahydrofurfuryl (meth)acrylate; Silyl group-containing monomers such as vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-(meth)acryloxypropyltrimethoxysilane; Hydroxy group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, 2-hydroxyethyl allyl ether; Vinyl group-containing sulfonic acid compounds such as vinyl sulfonic acid, 3-acryloxypropane-1-sulfonic acid, 3-acryloxyoctyloxybenzenesulfonic acid, 3-acryloxybenzenediazosulfonic acid, 3-acryloxyazobenzene-4'-sulfonic acid, 2-acryloylamino-2-methylpropane-1-sulfonic acid, 2-acryloylamide-2-methylpropanesulfonic acid, acrylonitrile-tert-butylsulfonic acid and their salts, etc. can be mentioned.

[0014] The content rate of the other vinyl compound (a2) is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, preferably 80% by mass or less, more preferably 60% by mass or less, and still more preferably 50% by mass or less in the total amount of the vinyl monomer (a).

[0015] The total content rate of the conjugated diene compound (a1) and the other vinyl compound (a2) is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and preferably 100% by mass or less in the total amount of the vinyl monomer (a).

[0016] The glass transition temperature of the vinyl polymer (A1) is preferably -100 °C or higher, more preferably -80 °C or higher, preferably 120 °C or lower, more preferably 100 °C or lower, still more preferably 50 °C or lower, and even more preferably 25 °C or lower.

[0017] The glass transition temperature Tg(A1) of the vinyl polymer (A1) represents a value obtained by converting the glass transition temperature Tga at absolute temperature obtained by the following formula (FOX formula) into Celsius temperature. 1 / Tga = Σ(Wi / Tgi) ···

[0018] In the above formula, Tga represents the glass transition temperature (unit: absolute temperature) of a polymer composed only of each vinyl monomer (a) used for the synthesis of the vinyl polymer (A1). Wi represents the mass ratio of each vinyl monomer (a) in the raw material of the vinyl polymer (A1). Tgi represents the glass transition temperature (unit: absolute temperature) of a homopolymer formed only of each vinyl monomer (a).

[0019] The details of the FOX method are described in Bulletin of the American Physical Society, Series 2, Volume 1, Number 3, page 123 (1956). Also, for the glass transition temperatures (Tgi) of various homopolymers of monomers for calculation by the FOX method, the values described in, for example, Painting and Coatings (Coating Publishing Co., 10 (No. 358), 1982) can be adopted.

[0020] The content of the vinyl polymer (A1) is preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 10% by mass or more, even more preferably 20% by mass or more, particularly preferably 30% by mass or more in the composite resin (A), and preferably 90% by mass or less, more preferably 70% by mass or less, still more preferably 60% by mass or less, even more preferably 50% by mass or less.

[0021] The urethane resin (A2) is a resin having a urethane bond in the molecule, and is preferably a reaction product of a polyol (b1), a polyisocyanate (b2), and, if necessary, a chain extender (b3). When using the chain extender (b3), the urethane resin (A2) can be obtained as a reaction product of a reaction product of a polyol (b1) and a polyisocyanate (b2) and the chain extender (b3).

[0022] As the polyol (b1), one or more kinds can be used. For example, polyether polyol, polyester polyol, polycarbonate polyol, polyolefin polyol, etc. can be mentioned, and it is preferable to contain polymer polyols (number average molecular weight of 500 or more, preferably 3,000 or less) such as polyester polyol and polycarbonate polyol, and if necessary, a polyol having a hydrophilic group and a low molecular weight polyol (number average molecular weight of less than 500, preferably 50 or more) may be contained.

[0023] Examples of the polyether polyol include those obtained by addition polymerization (ring-opening polymerization) of an alkylene oxide using one or more compounds having two or more active hydrogen atoms as an initiator.

[0024] Examples of the initiator include linear diols such as ethylene glycol, diethylene glycol, triethylene glycol, trimethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol; branched diols such as neopentyl glycol; triols such as glycerin, trimethylolethane, trimethylolpropane, pyrogallol; polyols such as sorbitol, sucrose, aconitic sugar; tricarboxylic acids such as aconitic acid, trimellitic acid, hemimellitic acid; phosphoric acid; polyamines such as ethylenediamine, diethylenetriamine; triisopropanolamine; phenolic acids such as dihydroxybenzoic acid, hydroxyphthalic acid; 1,2,3-propanetrithiol, and the like.

[0025] Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and the like.

[0026] As the polyether polyol, it is preferable to use polyoxytetramethylene glycol obtained by addition polymerization (ring-opening polymerization) of tetrahydrofuran to the initiator.

[0027] Examples of the polyester polyol include polyester polyols obtained by an esterification reaction of a low molecular weight polyol (for example, a polyol having a molecular weight of 50 or more and 300 or less) and a polycarboxylic acid; polyester polyols obtained by a ring-opening polymerization reaction of a cyclic ester compound such as ε-caprolactone; and copolymer polyester polyols thereof.

[0028] As the low molecular weight polyol, a polyol having a molecular weight of 50 or more and 300 or less can be used. For example, aliphatic polyols having 2 to 6 carbon atoms such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol; alicyclic structure-containing polyols such as 1,4-cyclohexanediol and cyclohexanedimethanol; aromatic structure-containing polyols such as bisphenol compounds such as bisphenol A and bisphenol F and their alkylene oxide adducts, etc. can be mentioned.

[0029] As the polycarboxylic acid, aliphatic polycarboxylic acids such as succinic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid; aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid; and anhydrides or ester-forming derivatives of the aliphatic polycarboxylic acids and aromatic polycarboxylic acids, etc. can be mentioned.

[0030] As the polycarbonate polyol, for example, reaction products of carbonic esters and polyols; reaction products of phosgene and bisphenol A, etc. can be mentioned.

[0031] As the carbonic ester, for example, methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclo carbonate, diphenyl carbonate, etc. can be mentioned.

[0032] As the polyol capable of reacting with the carbonic ester, for example, the polyols exemplified as the above low molecular weight polyol; high molecular weight polyols (for example, weight average molecular weight of 500 or more and 5,000 or less) such as polyether polyols (polyethylene glycol, polypropylene glycol, etc.), polyester polyols (polyhexamethylene adipate, etc.) can be mentioned.

[0033] Examples of the polyolefin polyol include polyisobutene polyol, hydrogenated polybutadiene polyol, hydrogenated polyisoprene polyol, and the like.

[0034] The total content of the polymer polyol (preferably polyether polyol, polyester polyol, polycarbonate polyol, and polyolefin polyol) contained in the polyol (b2) is preferably 30% by mass or more, more preferably 40% by mass or more, and preferably 100% by mass or less in the polyol (b2).

[0035] Examples of the hydrophilic group in the polyol having a hydrophilic group include an anionic group, a cationic group, a nonionic group, etc. By using a polyol having a hydrophilic group, the water dispersibility of the composite resin (A) can be improved. As the polyol having a hydrophilic group, for example, a polyol other than the above polyether polyol, polyester polyol, polycarbonate polyol, and polyolefin polyol can be used. Specifically, a polyol having an anionic group, a polyol having a cationic group, and a polyol having a nonionic group can be used. Among these, it is preferable to use a polyol having an anionic group or a polyol having a cationic group.

[0036] Examples of the polyol having an anionic group include a polyol having a carboxy group and a polyol having a sulfonic acid group.

[0037] Examples of the polyol having a carboxy group include hydroxy acids such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid; and reaction products of the polyol having a carboxy group and the polycarboxylic acid. As the hydroxy acid, 2,2-dimethylolpropionic acid is preferable.

[0038] Examples of the polyol having a sulfonic acid group include dicarboxylic acids having a sulfonic acid group such as 5-sulfoisophthalic acid, sulfoterephthalic acid, 4-sulfophthalic acid, 5-(4-sulfophenoxy)isophthalic acid; and polyester polyols obtained by reacting a salt of the dicarboxylic acid with the aromatic structure-containing polyol.

[0039] Examples of the polyol having a cationic group include N-methyl-diethanolamine; polyols having a tertiary amino group such as polyols obtained by reacting a compound having two epoxies in one molecule with a secondary amine.

[0040] Examples of the polyol having a nonionic group include polyols having a polyoxyethylene structure.

[0041] When the polyol (b2) contains a polyol having a hydrophilic group, its content is preferably 0.3 parts by mass or more, more preferably 1 part by mass or more, still more preferably 2% by mass or more, particularly preferably 5% by mass or more, and preferably 30 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 10 parts by mass or less, based on 100 parts by mass in total of the polyol (b2).

[0042] Examples of the low molecular weight polyol include alkanediols such as ethylene glycol, diethylene glycol, 1,2-propylene glycol, dipropylene glycol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanediol, 1,6-hexanediol; cycloalkanedialkanols such as cyclohexanedimethanol; and polyols having a polymerizable unsaturated group.

[0043] Examples of the polyol having a polymerizable unsaturated group include the compound represented by the following formula (1) and the compound represented by formula (2).

[0044] [Chemical formula] [In formula (1), R 1 represents a linear alkylene group having a side chain with an atomic group containing a polymerizable unsaturated group.]

[0045] [Chemical formula] [In formula (2), R 1 and R 3 each independently represent an optionally having a side chain with an atomic group containing a polymerizable unsaturated group, and the total number of atomic groups containing the polymerizable unsaturated group contained in R 1 and R 3 is one or more. R 2 represents an alkylene group having 1 to 20 carbon atoms.]

[0046] Examples of the atomic group containing the polymerizable unsaturated group include a vinyl group, a vinyloxy group, a (meth)acryloyl group, etc. R 1 , R 3 may have a side chain with a hydroxyl group in addition to a side chain with an atomic group containing a polymerizable unsaturated group.

[0047] Examples of the linear alkylene group represented by the above R 1 , R 3 include a methylene group, an ethylene group, a propylene group, a butanediyl group, a pentanediyl group, a hexanediyl group, a heptanediyl group, an octanediyl group, a nonanediyl group, etc. The number of carbon atoms of the linear alkylene group is 1 or more, preferably 2 or more, for example 50 or less, preferably 20 or less, more preferably 6 or less, more preferably 5 or less, and particularly preferably 2.

[0048] In the compound represented by the above formula (1) and the compound represented by formula (2), the number of side chains with an atomic group containing a polymerizable unsaturated group is 1 or more, preferably 2 or more per molecule, for example 10 or less, preferably 5 or less.

[0049] Examples of the compound represented by the formula (1) include pentaerythritol (meth)acrylate, pentaerythritol di(meth)acrylate [dimethylolpropane di(meth)acrylate], trimethylolmethane (meth)acrylate, dimethylolmethane di(meth)acrylate, triethylolmethane (meth)acrylate, diethylolmethane di(meth)acrylate, triethylolpropane (meth)acrylate, diethylolpropane di(meth)acrylate, tripropanolmethane (meth)acrylate, dipropanolmethane di(meth)acrylate, tripropanolpropane (meth)acrylate, dipropanolpropane di(meth)acrylate, tributanolmethane (meth)acrylate, dibutanolmethane di(meth)acrylate, tributanolpropane (meth)acrylate, dibutanolpropane di(meth)acrylate, and the like.

[0050] Examples of the compound represented by the formula (2) include bis(3-acryloyloxy-2-hydroxypropoxy)methane, 1,2-bis(3-acryloyloxy-2-hydroxypropoxy)ethane, 1,3-bis(3-acryloyloxy-2-hydroxypropoxy)propane, 1,4-bis(3-acryloyloxy-2-hydroxypropoxy)butane, 1,5-bis(3-acryloyloxy-2-hydroxypropoxy)pentane, and the like.

[0051] As the polyisocyanate (b2), one or more than one kind can be used. For example, aromatic polyisocyanates such as 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, crude diphenylmethane diisocyanate, phenylene diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate, lysine diisocyanate; alicyclic structure-containing polyisocyanates such as cyclohexane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, etc. can be mentioned.

[0052] The molar ratio (NCO / OH) of -NCO contained in the polyisocyanate (b2) to -OH contained in the polyol (b1) is preferably 0.3 or more, more preferably 0.5 or more, still more preferably 0.8 or more, and preferably 5.0 or less, more preferably 3.0 or less, still more preferably 2.0 or less.

[0053] As the chain extender (b3), one or more thereof can be used. For example, diamines such as ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, 1,4-cyclohexanediamine; N-hydroxymethylaminoethylamine, N-hydroxyethylaminoethylamine, N-hydroxypropylaminopropylamine, N-ethylaminoethylamine, N-methylaminopropylamine; polyamines such as diethylenetriamine, dipropylenetriamine, triethylenetetramine; hydrazine, N,N'-dimethylhydrazine, 1,6-hexamethylenebishydrazine; succinic dihydrazide, adipic dihydrazide, glutaric dihydrazide, sebacic dihydrazide, isophthalic dihydrazide; hydrazine compounds such as β-semicarbazidepropionic acid hydrazide; cyclic polyamines such as piperazine, 2,5-dimethylpiperazine; glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, saccharose, methylene glycol, glycerin, sorbitol; phenols such as bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, hydrogenated bisphenol A, hydroquinone, and water, etc. can be mentioned.

[0054] The urethane resin (A2) may be a reaction product of the polyol (b1), the polyisocyanate (b2), the chain extender (b3) used as necessary, and an alcohol compound (b4) having a polymerizable unsaturated group.

[0055] The number of polymerizable unsaturated groups contained in the alcohol compound (b4) having a polymerizable unsaturated group is 1 or more, for example, 20 or less, preferably 15 or less, more preferably 10 or less.

[0056] Examples of the alcohol compound (b4) having a polymerizable unsaturated group include monoalcohol compounds, such as hydroxyalkyl (meth)acrylates (the number of carbon atoms in the hydroxyalkyl group is, for example, 2 to 10, preferably 2 to 5) such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate; di(meth)acrylate compounds of triols such as trimethylolpropane di(meth)acrylate and glycerol di(meth)acrylate; tri(meth)acrylate compounds of tetraols such as pentaerythritol tri(meth)acrylate and ditrimethylolpropane tri(meth)acrylate; polyalkoxy (preferably, polyethoxy, polypropoxy, etc.) compounds such as the di(meth)acrylate compounds of the triols and the tri(meth)acrylate compounds of the tetraols; block copolymer equivalents such as the di(meth)acrylate compounds of the triols and the tri(meth)acrylate compounds of the tetraols, and the like.

[0057] When the urethane resin (A2) has an anionic group, the aqueous resin composition may contain a basic compound. Examples of the basic compound include organic amines such as ammonia, triethylamine, morpholine, monoethanolamine, and diethylethanolamine; metal hydroxides containing sodium hydroxide, potassium hydroxide, lithium hydroxide, and the like. From the viewpoint of improving the water dispersion stability of the aqueous resin composition, the molar ratio (basic group / anionic group) of the basic compound to the anionic group is preferably 0.5 or more and 3.0 or less, more preferably 0.8 or more and 2.0 or less.

[0058] When the urethane resin (A2) has an anionic group, the acid value of the urethane resin (A2) is preferably 0.1 mgKOH / g or more, more preferably 5 mgKOH / g or more, still more preferably 10 mgKOH / g or more, and preferably 100 mgKOH / g or less, more preferably 70 mgKOH / g or less, still more preferably 50 mgKOH / g or less. The acid value referred to in this specification is a theoretical value calculated by calculating the amount of anionic groups contained in the urethane resin (A2) based on the raw material composition, and based on this, calculating the number of milligrams of potassium hydroxide required to neutralize 1 g of the urethane resin (A2).

[0059] When the urethane resin (A2) has a cationic group, the aqueous resin composition may contain carboxylic acids such as formic acid, acetic acid, propionic acid, succinic acid, glutaric acid, adipic acid; hydroxy acids such as tartaric acid; acidic compounds such as phosphoric acid. A part or all of the tertiary amino group as the cationic group may be quaternized by a quaternizing agent such as dimethyl sulfate, diethyl sulfate, methyl chloride, ethyl chloride, etc.

[0060] When the urethane resin (A2) has a cationic group, the amine value of the urethane resin (A2) is preferably 2 mgKOH / g or more and 50 mgKOH / g or less, more preferably 5 mgKOH / g or more and 30 mgKOH / g or less. The amine value referred to in this specification is a theoretical value calculated by calculating the amount of cationic groups contained in the urethane resin (A2) based on the raw material composition, and based on this, calculating the product of the number of moles (mmol) of hydrogen chloride required to neutralize 1 g of the urethane resin (A2) and the formula weight of potassium hydroxide (56.1 g / mol).

[0061] In the urethane resin (A2), the amount of urea bond groups is, for example, 1.0 mol / g or less, preferably 0.1 mol / g or less, more preferably 0.01 mol / g or less, and the lower limit is 0 mol / g. The amount of urea bond groups can be calculated as a theoretical value based on the raw materials used in the synthesis of the urethane resin (A2).

[0062] The weight average molecular weight of the urethane resin (A2) is preferably 3,000 or more, more preferably 5,000 or more, still more preferably 10,000 or more, even more preferably 30,000 or more, and preferably 1,000,000 or less, more preferably 500,000 or less, still more preferably 300,000 or less.

[0063] In this specification, unless otherwise specified, the weight-average molecular weight and the number-average molecular weight can be measured by gel permeation chromatography (GPC) using polystyrene as a standard sample.

[0064] The glass transition temperature of the urethane resin (A2) is preferably -80°C or higher, more preferably -50°C or higher, still more preferably -20°C or higher, and preferably 120°C or lower, more preferably 100°C or lower, still more preferably 80°C or lower. When the glass transition temperature of the urethane resin (A2) is within the above range, the mobility of the urethane resin (A2) is good, and it is easy to exhibit the effects of the present invention. The glass transition temperature of the urethane resin (A2) can be measured by a method in accordance with JIS K7121 using a differential scanning calorimeter.

[0065] The difference (Tg(A2) - Tg(A1)) between the glass transition temperature Tg(A2) of the urethane resin (A2) and the glass transition temperature Tg(A1) of the vinyl polymer (A1) is -40°C or higher, preferably -30°C or higher, more preferably -20°C or higher, still more preferably 0°C or higher, and 140°C or lower, preferably 130°C or lower, still more preferably 120°C or lower, even more preferably 100°C or lower, still even more preferably 90°C or lower, and particularly preferably 80°C or lower. When the difference in the glass transition temperature is within the above range (Tg(A2) - Tg(A1)), the balance of the mobilities of the urethane resin (A2) and the vinyl polymer (A1) is good, and it is possible to form a coating film having a hydrophobic surface by heating.

[0066] The glass transition temperature of the urethane resin (A2) can be measured by a differential scanning calorimeter (DSC).

[0067] The content of the urethane resin (A2) is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, still more preferably 1 part by mass or more, relative to 1 part by mass of the vinyl polymer (A1), and is preferably 100 parts by mass or less, more preferably 10 parts by mass or less, still more preferably 3 parts by mass or less.

[0068] The total content ratio of the vinyl polymer (A1) and the urethane resin (A2) is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more in the composite resin (A), and the upper limit is 100% by mass.

[0069] The gel fraction of the composite resin (A) is preferably 0.01% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass or more, even more preferably 10% by mass or more, and the upper limit is 100% by mass. For example, it is also acceptable that it is 90% by mass or less, and further 80% by mass or less.

[0070] The gel fraction of the composite resin (A) can be measured, for example, by the following method. First, the aqueous resin composition of the present invention is coated on a glass plate so that the film thickness after drying becomes 0.5 mm, dried at 80 ° C for 2 hours, then peeled off from the glass plate, and further dried at 140 ° C for 5 minutes, and then cut into a circle with a diameter of 29 mm to obtain a sample. Measure the weight of the sample before solvent immersion and designate it as G1. Next, after immersing the sample in toluene at room temperature for 24 hours, separate the solvent-insoluble portion of the sample by filtering through an 80-mesh wire mesh, dry it at 110 ° C for 1 hour, and then weigh it and designate it as G2. The value obtained based on the following formula is defined as the gel fraction. Gel fraction (% by mass) = (G2 / G1) × 100

[0071] In the composite resin (A), it is preferable that at least a part of the surface of the vinyl polymer (A1) is coated with the urethane resin (A2), and it is preferable that a layer of the urethane resin (A2) is formed on the surface of the vinyl polymer (A1). The vinyl polymer (A1) generally has high hydrophobicity and is difficult to disperse in water as it is. However, since the urethane resin (A2) coats at least a part of the surface of the vinyl polymer (A1), the dispersibility in an aqueous medium becomes good. The vinyl polymer (A1) and the urethane resin (A2) may or may not be chemically bonded.

[0072] The composite resin can be produced by polymerizing a vinyl monomer (a) in an aqueous medium (B) described later in the presence of the urethane resin (A2). Since the vinyl monomer (a) is hydrophobic, by coexisting with the urethane resin (A2) in the aqueous medium (B), at least a part of the vinyl monomer (a) is incorporated into the urethane resin (B2), and by performing a polymerization reaction in this state, the composite resin (A) of the present invention can be produced.

[0073] More specifically, the urethane resin (A2) is preferably used for the polymerization of the vinyl monomer (a) in a state of being dispersed in the aqueous medium (B) (pre-dispersion liquid). The pre-dispersion liquid in which the urethane resin (A2) is dispersed in the aqueous medium (B) can be produced, for example, by reacting the polyol (b1) and the polyisocyanate (b2) in the absence of a solvent or in the presence of an organic solvent, and if necessary, further reacting a chain extender (b3). From the viewpoints of safety and reduction of the environmental load, a part or all of the organic solvent may be removed by distillation under reduced pressure during or after the production of the urethane resin (A2).

[0074] During the polymerization reaction, if necessary, an additive (C) described later may coexist, or the additive (C) may be added after the polymerization reaction.

[0075] When polymerizing the vinyl monomer (a), it is preferable to coexist a radical polymerization initiator. As the polymerization initiator, a photopolymerization initiator or a thermal polymerization initiator can be used. Examples of the photopolymerization initiator include benzophenone, benzyl, Michler's ketone, thioxanthone, anthraquinone, benzoin, dialkoxyacetophenone, acyloxime ester, benzyl ketal, hydroxyalkylphenone, halogeno ketone, etc. The photopolymerization initiator may be used in combination with a tertiary amine such as methylamine, diethanolamine, N-methyldiethanolamine, tributylamine, etc. as necessary. Examples of the thermal polymerization initiator include azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2-methylpropionamidine) dihydrochloride, 4,4'-azobis(4-cyano)valeric acid, 2,2'-azobis(2-amidinopropane) dihydrochloride; organic peroxides such as benzoyl peroxide, tert-butyl hydroperoxide, tert-butyl peroxy pivalate, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, di-tert-butyl peroxide, di-tert-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide, lauroyl peroxide, decanoyl peroxide, tert-butyl cumyl peroxide, dicumyl peroxide, tert-butyl peroxy laurate, tert-butyl peroxybenzoate, cumene hydroperoxide, paramethane hydroperoxide, etc.; and thermal polymerization initiators such as inorganic peroxides such as hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, etc. can be used.

[0076] The amount of the radical polymerization initiator is preferably 0.01 part by mass or more, more preferably 0.1 part by mass or more, still more preferably 0.5 part by mass or more, and preferably 20 parts by mass or less, more preferably 10 parts by mass or less, still more preferably 5 parts by mass or less, based on 100 parts by mass in total of the vinyl compounds.

[0077] The composite resin (A) is preferably dispersed in the aqueous medium (B). The dispersion state of the composite resin (A) can be confirmed, for example, by the presence or absence of precipitates in the aqueous resin composition.

[0078] The content of the composite resin (A) in the aqueous resin composition is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, and preferably 70% by mass or less, more preferably 60% by mass or less, still more preferably 50% by mass or less.

[0079] Examples of the aqueous medium (B) include water, an organic solvent miscible with water, and a mixture thereof. As the organic solvent miscible with water, one or more kinds can be used. For example, alcohol solvents such as methanol, ethanol, n-propanol, isopropyl alcohol, 1,2-propylene glycol, and 1,3-butylene glycol; ketone solvents such as acetone and methyl ethyl ketone; glycol ether solvents such as ethylene glycol-n-butyl ether, diethylene glycol-n-butyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol dimethyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether, dipropylene glycol dimethyl ether, dipropylene glycol-n-butyl ether, and tripropylene glycol methyl ether; lactam solvents such as N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone; amide solvents such as N,N-dimethylformamide, etc. are mentioned, and alcohol solvents are preferred.

[0080] In consideration of safety and reduction of the environmental load, the aqueous medium (B) is preferably only water or a mixture of water and an organic solvent miscible with water, and more preferably only water. The water content is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more in 100% by mass of the aqueous medium (B).

[0081] The content ratio of the aqueous medium (B) is preferably 30% by mass or more and 80% by mass or less, more preferably 50% by mass or more and 70% by mass or less, based on 100% by mass of the total amount of the aqueous resin composition.

[0082] The aqueous resin composition of the present invention may further contain various additives (C) such as a crosslinking agent, a surfactant, a plasticizer, an antistatic agent, a wax, a light stabilizer, a flow regulator, a dye, a leveling agent, a rheology control agent, an ultraviolet absorber, an antioxidant, a photocatalytic compound, an inorganic pigment, an organic pigment, an extender pigment, a curing agent, a curing catalyst, an emulsifier, a dispersion stabilizer, etc. The content of the additive (C) is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and still more preferably 1 part by mass or less, based on 100 parts by mass of the composite resin (A).

[0083] The aqueous resin composition of the present invention can initially be homogeneous and finally form a coating film with a hydrophobic surface, and is suitable for paper coating / impregnation processing, fibers / non-woven fabrics, carpets, civil engineering building materials, mortar cement, automobile parts, tire cords, paints, pastes, rust preventive coatings, adhesives, plastic modification, cosmetic puffs, electronic materials, adhesives (general), coating / impregnation (non-woven fabrics / paper), fiber impregnation / reinforcing fiber processing (carpets, etc.), moisture-proof / water-resistant coatings, cement / mortar, building material processing / wood adhesion, synthetic leather, artificial leather, gloves, contraception, ink acceptance agents, ink dispersing agents, etc.

Examples

[0084] Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, and it is of course possible to appropriately modify and implement within the scope that can conform to the gist of the foregoing and following descriptions, and all of them are included in the technical scope of the present invention.

[0085] (Synthesis Example 1: Synthesis of polyester polyol (1)) While introducing nitrogen gas in a reaction vessel equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 35.4 parts of isophthalic acid, 17.8 parts of sebacic acid, 7.8 parts of adipic acid, 6.2 parts of ethylene glycol, 22.9 parts of neopentyl glycol, 11.7 parts of 1,6 - hexanediol, and 0.03 part of dibutyltin oxide were charged, and a polycondensation reaction was carried out at 230 °C for 24 hours until the acid value reached 1 or less at 180 - 230 °C to obtain polyester polyol (1) [acid value 0.6 mg KOH / g, hydroxyl value 42.5 mg KOH / g].

[0086] (Synthesis Example 2: Synthesis of Polyester Polyol (2)) While introducing nitrogen gas in a reaction vessel equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 27.6 parts by mass of isophthalic acid, 27.6 parts by mass of terephthalic acid, 11.7 parts by mass of ethylene glycol, 19.9 parts by mass of diethylene glycol, and 0.03 part by mass of dibutyltin oxide were charged, and a polycondensation reaction was carried out at 230 °C for 24 hours until the acid value reached 1 or less at 180 - 230 °C to obtain polyester polyol (2) [acid value 0.6 mg KOH / g, hydroxyl value 48.0 mg KOH / g].

[0087] (Production Example 1: Synthesis of Urethane Resin (1)) 69.0 parts by mass of the polyester polyol (1) of Synthesis Example 1 was dehydrated in a reaction vessel at 100 °C under reduced pressure, and then cooled to 80 °C. Thereafter, 93.30 parts by mass of methyl ethyl ketone was added and stirred to mix uniformly. Next, 3.0 parts by mass of 1,4-butanediol and 6.1 parts by mass of 2,2'-dimethylolpropionic acid were added, and then 19.4 parts by mass of tolylene diisocyanate was added, and the mixture was reacted at 80 °C for 12 hours to carry out a urethanization step. It was confirmed that the isocyanate value became 0.1% or less, 0.3 part by mass of n-butanol was added, and after further reacting for 2 hours, the mixture was cooled to 50 °C to obtain a hydrophilic group-containing polyurethane resin (I) with a non-volatile content of 51.0%. Next, 4.6 parts by mass of triethylamine was added to the hydrophilic group-containing polyurethane resin (I), and 548 parts by mass of ion-exchanged water was slowly added to carry out water solubilization. Then, methyl ethyl ketone was removed at 30 to 50 °C under reduced pressure to prepare a urethane resin (1) with a non-volatile content of 23.0%. The acid value was 26.2 mgKOH / g. The contact angles were 75 degrees for water, 35 degrees for diiodomethane, and 53 degrees for ethylene glycol.

[0088] (Production Example 2: Synthesis of urethane resin (2)) 75.7 parts by mass of the polyester polyol (2) of Synthesis Example 2 was dehydrated in a reaction vessel at 100 °C under reduced pressure, and then cooled to 80 °C. Thereafter, 67.89 parts by mass of methyl ethyl ketone was added and stirred to mix uniformly. Next, 6.1 parts by mass of 2,2-dimethylolpropionic acid was added, and then 20.3 parts by mass of isophorone diisocyanate was added, and the mixture was reacted at 80 °C for 12 hours to carry out a urethanization step. It was confirmed that the isocyanate value became 0.1% or less, 0.3 part by mass of n-butanol was added, and after further reacting for 2 hours, the mixture was cooled to 50 °C to obtain an organic solvent solution of a urethane prepolymer. Furthermore, 320 parts by mass of water was added and sufficiently stirred to obtain an aqueous dispersion of a urethane resin. Then, by aging and desolventizing, a urethane resin (2) with a non-volatile content of 20% by mass was obtained. The acid value was 12.6 mgKOH / g. The contact angles were 75 degrees for water, 43 degrees for diiodomethane, and 50 degrees for ethylene glycol.

[0089] (Production Example 3: Synthesis of Urethane Resin (3)) In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 267 parts by mass of a polycarbonate polyol (number average molecular weight 2000) obtained by reacting 1,6-hexanediol and diethyl carbonate, 73 parts by mass of isophorone diisocyanate, 15 parts by mass of 2,2-dimethylolpropionic acid, and 148 parts by mass of a mixed solvent of methyl ethyl ketone were reacted to obtain an organic solvent solution of a urethane prepolymer having isocyanate groups at the molecular terminals. Next, 14 parts by mass of triethylamine was added to neutralize some or all of the carboxyl groups of the urethane prepolymer, and further 800 parts by mass of water and 4.7 parts by mass of an 80% aqueous hydrazine solution were added and stirred well to obtain an aqueous dispersion of the urethane resin. Then, by aging and desolventizing, a urethane resin (3) with a nonvolatile content of 35% by mass was obtained. The acid value was 21.2 mgKOH / g. The contact angles were 80 degrees for water, 37 degrees for diiodomethane, and 55 degrees for ethylene glycol.

[0090] (Example 1: Synthesis of Latex Composite Urethane Resin (1)) 126 parts by mass of ion-exchanged water was added to 321 parts by mass of the urethane resin (1) obtained in Production Example 1, and 31.7 parts of butadiene was reacted under the conditions of monomer batch emulsion polymerization (reaction temperature 70 °C) with 0.5 part of ammonium persulfate (APS). Next, the unreacted monomer was removed by concentration, and after adjusting the water content, a latex composite urethane resin (1) with a solid content of 25% was obtained.

[0091] (Example 2: Synthesis of Latex Composite Urethane Resin (2)) 196 parts by mass of ion-exchanged water was added to 229 parts by mass of the urethane resin (1) obtained in Production Example 1, and 52.8 parts of butadiene was reacted under the conditions of monomer batch emulsion polymerization (reaction temperature 70 °C) with 0.5 part of ammonium persulfate (APS). Next, the unreacted monomer was removed by concentration, and after adjusting the water content, a latex composite urethane resin (2) with a solid content of 25% was obtained.

[0092] (Example 3: Synthesis of Latex Composite Urethane Resin (3)) To 229 parts by mass of the urethane resin (1) obtained in Production Example 1, 196 parts by mass of ion-exchanged water was added, and 36.9 parts of butadiene and 15.8 parts of styrene were reacted under the conditions of batch emulsion polymerization of monomers (reaction temperature: 70°C) with 0.5 part of ammonium persulfate (APS). Next, concentration for removing unreacted monomers was carried out, and after adjusting the water content, a latex composite urethane resin (3) with a solid content of 25% was obtained.

[0093] (Example 4: Synthesis of Latex Composite Urethane Resin (4)) To 229 parts by mass of the urethane resin (1) obtained in Production Example 1, 196 parts by mass of ion-exchanged water was added, and 15.8 parts of butadiene and 36.9 parts of styrene were reacted under the conditions of batch emulsion polymerization of monomers (reaction temperature: 70°C) with 0.5 part of ammonium persulfate (APS). Next, concentration for removing unreacted monomers was carried out, and after adjusting the water content, a latex composite urethane resin (4) with a solid content of 25% was obtained.

[0094] (Example 5: Synthesis of Latex Composite Urethane Resin (5)) To 321 parts by mass of the urethane resin (1) obtained in Production Example 1, 126 parts by mass of ion-exchanged water was added, and 15.8 parts of butadiene and 15.8 parts of isostearyl acrylate were reacted under the conditions of batch emulsion polymerization of monomers (reaction temperature: 70°C) with 0.5 part of ammonium persulfate (APS). Next, concentration for removing unreacted monomers was carried out, and after adjusting the water content, a latex composite urethane resin (5) with a solid content of 25% was obtained.

[0095] (Example 6: Synthesis of Latex Composite Urethane Resin (6)) To 321 parts by mass of the urethane resin (2) obtained in Production Example 2, 127 parts by mass of ion-exchanged water was added, and 30.9 parts of butadiene was reacted under the conditions of batch emulsion polymerization of monomers (reaction temperature: 60°C) with 0.5 part of ammonium persulfate (APS). Next, concentration for removing unreacted monomers was carried out, and after adjusting the water content, a latex composite urethane resin (6) with a solid content of 23% was obtained.

[0096] (Example 7: Synthesis of Latex Composite Urethane Resin (7)) 206 parts by mass of the urethane resin (3) obtained in Production Example 3 was added with 200 parts by mass of ion-exchanged water, and 71.9 parts of butadiene was reacted under the conditions of batch emulsion polymerization of monomers (reaction temperature: 60°C) with 0.5 part of ammonium persulfate (APS). Next, concentration for removing unreacted monomers was carried out, and after adjusting the water content, a latex composite urethane resin (7) with a solid content of 38% was obtained.

[0097] (Comparative Example 1: Synthesis of latex composite urethane resin (8)) 196 parts by mass of ion-exchanged water was added to 229 parts by mass of the urethane resin (1) obtained in Production Example 1, and 52.8 parts of styrene was reacted under the conditions of batch emulsion polymerization of monomers (reaction temperature: 70°C) with 0.5 part of ammonium persulfate (APS). Next, concentration for removing unreacted monomers was carried out, and after adjusting the water content, a latex composite urethane resin (8) with a solid content of 25% was obtained.

[0098] (Comparative Example 2: Synthesis of latex composite urethane resin (9)) 126 parts by mass of ion-exchanged water was added to 321 parts by mass of the urethane resin (1) obtained in Production Example 1, and 4.8 parts of butadiene and 26.9 parts of methyl methacrylate were reacted under the conditions of batch emulsion polymerization of monomers (reaction temperature: 70°C) with 0.5 part of ammonium persulfate (APS). Next, concentration for removing unreacted monomers was carried out, and after adjusting the water content, a latex composite urethane resin (9) with a solid content of 25% was obtained.

[0099] (Comparative Example 3: Synthesis of latex composite urethane resin (10)) 115 parts by mass of ion-exchanged water was added to 317 parts by mass of the urethane resin (3) obtained in Production Example 3, and 13.3 parts of butadiene and 34.3 parts of methyl methacrylate were reacted under the conditions of batch emulsion polymerization of monomers (reaction temperature: 60°C) with 0.5 part of ammonium persulfate (APS). Next, concentration for removing unreacted monomers was carried out, and after adjusting the water content, a latex composite urethane resin (10) with a solid content of 38% was obtained.

[0100] For the obtained urethane resins (1) to (3) and latex composite urethane resins (1) to (10), the contact angles of water, diiodomethane or ethylene glycol were measured by the following method. [Method for Measuring Contact Angle] Urethane resins (1) to (3) and latex composite urethane resins (1) to (10) were applied to a glass substrate and dried at 140 °C for 3 minutes. Then, 1 μL of water, diiodomethane, or ethylene glycol was dropped as a solvent, and the wetting spread angle after 30 seconds was measured at room temperature (25 °C) and atmospheric pressure (1013 hPa). For each solvent, the difference between the contact angle of the urethane resin used in the production of the latex composite urethane resin and the contact angle of the latex composite urethane resin (contact angle of latex composite urethane resin - contact angle of urethane resin. Hereinafter, it may be referred to as "Δθ") was calculated, and the total value of Δθ for water, diiodomethane, and ethylene glycol (δθ(water) + Δθ(diiodomethane) + Δθ(ethylene glycol). Hereinafter, it may be referred to as "Σ(Δθ)") was calculated, and the surface hydrophobicity was evaluated according to the following evaluation criteria. 〇: Σ(Δθ) is 30° or more △: Σ(Δθ) is 20° or more and less than 30° ×: Σ(Δθ) is less than 20°

[0101] [Measurement of Glass Transition Temperature of Urethane Resin (A2)] The glass transition temperature of urethane resin (A2) was measured by a method conforming to JIS K7121 using a differential scanning calorimeter "DSC Q-100" (manufactured by TA Instrument). Specifically, the heat change of a sample from which the solvent was completely removed by vacuum suction was measured in the range of -100 °C to +200 °C at a heating rate of 20 °C / min, and the point where a straight line equidistant from the extended straight line of each baseline in the vertical axis direction intersects the curve of the stepwise change part of the glass transition was taken as the glass transition temperature.

[0102]

Table 1

[0103] Examples 1 to 7 are examples of the present invention, and it was possible to provide an aqueous resin composition that is homogeneous during coating and can form a coating film having a hydrophobic surface after heating. In Comparative Examples 1 to 3, the difference between the glass transition temperature of the urethane resin (A2) and the glass transition temperature of the vinyl polymer (A1) was less than -40°C, and the hydrophobicity after heating was not sufficiently satisfactory.

Claims

1. Aqueous resin composition comprising a composite resin (A) and an aqueous medium (B), wherein the composite resin (A) comprises a vinyl polymer (A1) and a urethane resin (A2), the vinyl polymer (A1) is a polymer having units derived from a vinyl monomer (a) containing a conjugated diene compound (a1) and another vinyl compound (a2) other than the conjugated diene compound (a1), the content of the conjugated diene compound (a1) is 30% by mass or more based on the total amount of the vinyl monomer (a), the total content of the conjugated diene compound (a1) and the other vinyl compound (a2) in the total amount of the vinyl monomer (a) is 100% by mass, and the difference (Tg(A2) - Tg(A1)) between the glass transition temperature Tg(A2) of the urethane resin (A2) and the glass transition temperature Tg(A1) of the vinyl polymer (A1) is 49°C or more and 140°C or less.

2. The aqueous resin composition according to claim 1, wherein the glass transition temperature Tg(A2) of the urethane resin (A2) is 120°C or less.

3. The aqueous resin composition according to claim 1 or 2, wherein the content of the urethane resin (A2) is 0.1 part by mass or more and 100 parts by mass or less with respect to 1 part by mass of the vinyl polymer (A1).

4. The aqueous resin composition according to any one of claims 1 to 3, wherein the weight average molecular weight of the urethane resin (A2) is 5,000 or more and 500,000 or less.

5. The aqueous resin composition according to any one of claims 1 to 4, wherein the difference Δθ in contact angle by the following test method is 30° or more. [Test method] A water dispersion containing 20% by mass of the urethane resin (A2) was applied to a glass substrate, dried at 140°C for 3 minutes, and then 1 μL of solvent X was dropped thereon, and the contact angle when held at room temperature (25°C) and atmospheric pressure (1013 hPa) for 30 seconds was θ 0 For (solvent X), the water-based resin composition was applied to a glass substrate, dried at 140°C for 3 minutes, and then 1 μL of solvent X was dropped thereon, and the contact angle when held at room temperature (25°C) and atmospheric pressure (1013 hPa) for 30 seconds was θ 1 When (solvent X) is used, Δθ is calculated by the following formula. Δθ = {θ 1 (water) + θ 1 (iodomethane) + θ 1 (ethylene glycol)} - {θ 0 (water) + θ 0 (iodomethane) + θ 0 (ethylene glycol)}

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