Novel emulsion and paint composition using this emulsion

Abstract

To provide a novel emulsion and a composition containing the emulsion.SOLUTION: An emulsion of a (meth) acrylic polymer includes, as polymerization components, at least a reactive emulsifier (A) having a plurality of aromatic groups and a silane coupling agent (B) having a polymerizable unsaturated bond group.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to novel emulsions and the like.

Background Art

[0002] Interior and exterior paints (top coats, overcoats) for buildings are shifting from solvent-based paints to water-based paints from the perspective of environmental consideration.

[0003] As such water-based paints, for example, Patent Document 1 discloses a resin emulsion for overcoats of an acrylic resin using a styrene monomer and a silane group-containing monomer as raw materials.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a novel emulsion and a composition containing this emulsion (particularly, a composition for paints).

[0006] Another object of the present invention is to provide an emulsion capable of efficiently forming a paint film excellent in water resistance and a composition containing this emulsion.

[0007] Another object of the present invention is to provide an emulsion excellent in thickening responsiveness and a composition containing this emulsion.

Means for Solving the Problems

[0008] As described in Patent Document 1, water-based paints using emulsions are known. However, according to the study by the present inventor, some of such water-based paints have insufficient water resistance, and in some cases, when it rains during painting or when painting is carried out under high humidity such as during the rainy season, problems such as peeling of the paint film may occur due to a decrease in the strength of the paint film.

[0009] Also, the viscosity of the paint can be adjusted by adding a thickener. However, according to the study by the present inventor, depending on the type of emulsion (or the polymer constituting the emulsion), the thickener may not be able to sufficiently impart viscosity (that is, the thickening responsiveness is not sufficient), and a large amount of thickener may be required. And it has been found that using such a large amount of thickener may have an adverse effect on film formation (for example, reducing the water resistance of the paint film, increasing the viscosity over time during storage).

[0010] Under such circumstances, as a result of further intensive research to solve the above problems, the present inventor has found that by forming a polymerization component of an emulsion (or a polymer constituting the emulsion) from a polymerization component containing at least a reactive emulsifier (A) having a plurality of aromatic groups and a silane coupling agent (B) having a polymerizable unsaturated bonding group, it is possible to form a paint film excellent in water resistance and to improve or enhance the thickening responsiveness.

[0011] In addition to the above, the present inventor has obtained various new findings and has completed the present invention through further intensive studies.

[0012] That is, the present invention relates to the following inventions and the like. [1] An emulsion of a (meth)acrylic polymer having at least a reactive emulsifier (A) having a plurality of aromatic groups and a silane coupling agent (B) having a polymerizable unsaturated bonding group as a polymerization component. [2] The emulsion according to [1], wherein the reactive emulsifier (A) contains a reactive emulsifier represented by the following formula (1).

Chemical formula

[10] A paint comprising an emulsion described in any of [1] to [7] or a composition described in any of [8] to [9].

[11] A coating film formed with the paint described in

[10] .

[12]

[11] A building having the coating described above.

[13]

[11] Building material having the coating described above. [Effects of the Invention]

[0013] The present invention provides novel emulsions and compositions containing these emulsions. Such emulsions and compositions are useful for applications such as paints.

[0014] In another aspect of the present invention, emulsions and compositions capable of efficiently forming a coating film with excellent water resistance can be provided.

[0015] In another aspect of the present invention, an emulsion with excellent viscosity-enhancing responsiveness (capable of improving or enhancing viscosity-enhancing responsiveness) and a composition containing this emulsion can be provided. In such emulsions, sufficient viscosity can be obtained even with a small amount of thickener. Therefore, a coating film can be efficiently formed with a small amount of thickener, and in particular, a coating film with excellent water resistance, as described above, can be formed. In addition, since a large amount of thickener does not need to be used, the adverse effects of using thickeners in coating film formation (for example, the increase in viscosity over time during storage) can be reduced. [Modes for carrying out the invention]

[0016] <Emulsion> The emulsion of the present invention is an emulsion of a (meth)acrylic polymer (hereinafter sometimes referred to as (meth)acrylic polymer (a)) having at least a reactive emulsifier (A) having multiple aromatic groups and a silane coupling agent (B) having polymerizable unsaturated bonding groups as polymeric components (or monomer components). In the present invention, the polymerization component of the (meth)acrylic polymer (a) contains a reactive emulsifier (A) (particularly in combination with a silane coupling agent (B)), thereby efficiently improving or enhancing the water resistance of the coating film. Furthermore, by using such a specific reactive emulsifier (A), emulsions with excellent viscosity-enhancing responsiveness can be efficiently obtained. In particular, this viscosity-enhancing responsiveness appears to be further improved or enhanced when combined with a silane coupling agent (B).

[0017] The emulsion of the present invention is typically a dispersion in a solvent of (meth)acrylic polymers (or polymer particles) that are in an emulsion state.

[0018] (Reactive emulsifier (A)) Reactive emulsifiers (or reactive surfactants) (A) typically have a reactive group (or polymerizable group). As the reactive group, polymerizable unsaturated bonding groups (especially carbon-carbon double bonds) are preferred.

[0019] In the reactive emulsifier (A), the aromatic group is not particularly limited, and for example, C such as a phenyl group or a naphthyl group. 6-20 Examples include aromatic hydrocarbon groups. Furthermore, the number of aromatic groups only needs to be two or more; for example, it may be 2 to 10, 2 to 8, 2 to 6, 2 to 4, etc.

[0020] The reactive emulsifier (A) may be, for example, an anionic emulsifier, a nonionic emulsifier, a cationic emulsifier, or an amphoteric emulsifier, and among these, an anionic emulsifier is preferred from the viewpoint of dispersibility of emulsion particles.

[0021] Examples of anionic emulsifiers include sulfonate compounds and sulfate compounds.

[0022] As the reactive emulsifier (A), a reactive emulsifier represented by the following formula (1) is preferred. [ka] (In the formula, D represents the following formula (D-1) or (D-2), A represents an alkylene group having 2 to 4 carbon atoms, T represents a hydrogen atom or -SO3M (where M is a hydrogen atom, alkali metal atom, alkaline earth metal atom, or NH4), l represents 1 to 2, m represents 1 to 3, and n represents 1 to 1000.)

[0023] [ka]

[0024] [ka] (In the formula, R 1 (This represents a hydrogen atom or a methyl group.)

[0025] In particular, a reactive emulsifier represented by the following formula (2) is preferred.

[0026] [ka] (In the formula, M represents a hydrogen atom, alkali metal atom, alkaline earth metal atom, or NH4; m represents 1 to 3; and n represents 1 to 1000.)

[0027] In formulas (1) and (2) above, the alkali metal atom M is preferably sodium, potassium, or the like. Furthermore, as alkaline earth metal atoms, magnesium, calcium, and the like are preferred.

[0028] As the reactive emulsifier (A), commercially available products may be used, for example, Aqualon AR-10, Aqualon AR-1025, Aqualon AR-20, and Aqualon AR-2020, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

[0029] The reactive emulsifier (A) may be used alone or in combination of two or more types.

[0030] In the polymerization component, the proportion of the reactive emulsifier (A) depends on the type of other monomers, but from the viewpoint of improving the water resistance of the coating film, it may be, for example, 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more, and particularly preferably 1.3% by mass or more (for example, 1.5% by mass or more, 2% by mass or more, etc.) of the total polymerization component (or total monomer component). In the polymerization component, the proportion of the reactive emulsifier (A) may be, for example, 20% by mass or less of the total polymerization component, preferably 15% by mass or less, and more preferably 10% by mass or less.

[0031] Furthermore, these upper and lower limits may be combined as appropriate to set a suitable range (for example, 1 to 10 mass%, 1.5 to 10 mass%, etc.) (the same applies to others).

[0032] In the polymerization component, the proportion of the reactive emulsifier (A) depends on the type of other monomers, but from the viewpoint of improving the water resistance of the coating film, it may be, for example, 0.01 mol% or more of the total polymerization component, preferably 0.05 mol% or more, more preferably 0.1 mol% or more, and particularly preferably 0.13 mol% or more (for example, 0.15 mol% or more, 0.2 mol% or more, etc.). In the polymerization component, the proportion of the reactive emulsifier (A) may be, for example, 20 mol% or less of the total polymerization component, preferably 15 mol% or less, and more preferably 10 mol% or less.

[0033] Furthermore, these upper and lower limits may be combined as appropriate to set a suitable range (for example, 0.1 to 10 mol%, 0.15 to 10 mol%, etc.) (the same applies to others).

[0034] (Silane coupling agent (B)) Silane coupling agents (B) typically have polymerizable unsaturated bonding groups. Examples of polymerizable unsaturated bonding groups include vinyl groups, allyl groups, and (meth)acroyl groups. The number of polymerizable unsaturated bond groups is not particularly limited and may be one or more.

[0035] Silane coupling agents (B) include, for example, those having a silyl group to which a hydrolyzable (condensable) group (e.g., an alkoxy group, a halogen atom, etc.) is bonded. In the silane coupling agent (B), the number of silicon atoms may be 1 or more, or 2 or more (for example, oligomer or polymer-type silane coupling agents).

[0036] The silane coupling agent (B) may be, for example, a silane coupling agent (compound) represented by the following formula (3). (R2) n1 -Si-(R3) 4-n1 (3) (In the formula, R2 represents a group having a polymerizable unsaturated bond, either identical or different. R3 represents a hydrogen atom, a hydrolyzable condensable group, a hydrocarbon group, or an epoxy group (epoxy group-containing group), either identical or different. n1 represents an integer from 1 to 3.)

[0037] Examples of polymerizable unsaturated bonding groups in R2 include vinyl groups, allyl groups, and (meth)acroyl groups.

[0038] In R3, examples of hydrocarbon groups include alkyl groups and aryl groups (such as phenyl groups). Examples of alkyl groups include methyl groups and ethyl groups. 1-4 Examples include alkyl groups.

[0039] Examples of hydrolyzable condensable groups in R3 include hydroxyl groups, halogen atoms (such as chlorine atoms), alkoxy groups, acyloxy groups, aryloxy groups (such as phenoxy groups), and mercapto groups. In R3, the alkoxy group can be, for example, a methoxy group, an ethoxy group, etc. 1-4 Examples include alkoxy groups.

[0040] In R3, the acyloxy group can be, for example, an acetyloxy group, a propionyloxy group, etc. 2-4 Examples include acyloxy groups.

[0041] Among R3, from the viewpoint that polymers are crosslinked by condensation bonds between hydrolyzable condensable groups or by condensation bonds between hydrolyzable condensable groups and other polymers (for example, hydroxyl groups capable of bonding in other polymers), hydrolyzable condensable groups are preferred. As the hydrolyzable condensable group, for example, a hydroxyl group, a halogen atom (such as a chlorine atom), an alkoxy group, an acyloxy group, an aryloxy group (such as a phenoxy group), a mercapto group, etc. are preferred, and an alkoxy group and an acyloxy group are more preferred.

[0042] Specific examples of the silane coupling agent (B) include vinyl group-containing silanes {for example, halosilanes having a vinyl group (for example, vinyl mono- to trihalosilanes such as vinyltrichlorosilane), alkoxysilanes having a vinyl group [for example, vinylalkoxysilanes (for example, vinyl mono- to trialkoxysilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, preferably vinyl mono- to triC 1-4 alkoxysilanes), vinylalkoxyalkoxysilanes (for example, vinyltri(methoxyethoxy)silane, vinyltris(β-methoxyethoxy)silane, etc. vinyl mono- to tri(C 1-4 alkoxyC 1-4 alkoxy)silanes), styryl group-containing silanes (for example, styryl mono- to trialkoxysilanes such as p-styryltrimethoxysilane, preferably styryl mono- to triC 1-4 alkoxysilanes), etc.}, (meth)acryloyl group-containing silanes {for example, alkoxysilanes having a (meth)acryloyl group [for example, (meth)acryloxyalkyl mono- to trialkoxysilanes such as 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, preferably (meth)acryloxyC[[ID=I8]] 2-4 alkyl mono- to triC 1-4Alkoxysilanes], hydroxysilanes having a (meth)acryloyl group [for example, (meth)acryloxyalkylhydroxysilanes such as 3-(meth)acryloxypropylhydroxysilane and 3-(meth)acryloxypropylmethylhydroxysilane, preferably (meth)acryloxy C 2-4 Examples include alkylhydroxysilanes.

[0043] In particular, from the viewpoint of improving the water resistance of the coating film, alkoxysilanes having a (meth)acryloyl group are preferred, (meth)acryloxyalkyl mono to trialkoxysilanes are more preferred, and (meth)acryloxy C 2-4 Alkyl mono or tri-C 1-4 Alkoxysilanes [for example, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, etc.] are particularly preferred.

[0044] The silane coupling agent (B) may be used alone or in combination of two or more types.

[0045] In the polymerization component, the proportion of the silane coupling agent (B) depends on the type of other monomers, but from the viewpoint of improving the water resistance of the coating film, for example, it may be 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and particularly preferably 0.15% by mass or more of the total polymerization component. In the polymerization component, the proportion of the silane coupling agent (B) may be, for example, 15% by mass or less of the total polymerization component, preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less.

[0046] Furthermore, these upper and lower limits may be combined as appropriate to set a suitable range (for example, 0.05 to 10% by mass) (the same applies to the others).

[0047] In the polymerization component, the proportion of the silane coupling agent (B) depends on the type of other monomers, but from the viewpoint of improving the water resistance of the coating film, for example, it may be 0.01 mol% or more of the total polymerization component, preferably 0.05 mol% or more, more preferably 0.1 mol% or more, and particularly preferably 0.15 mol% or more. In the polymerization component, the proportion of the silane coupling agent (B) may be, for example, 15 mol% or less of the total polymerization component, preferably 10 mol% or less, more preferably 5 mol% or less, and particularly preferably 3 mol% or less.

[0048] Furthermore, these upper and lower limits may be combined as appropriate to set a suitable range (for example, 0.05 to 10 mol%) (the same applies to the others).

[0049] Furthermore, the silane coupling agent (B), which is a constituent unit of the polymerization component (polymer), has a silane functional group (silyl group) in its constituent unit, and can crosslink polymers (a) with these silyl groups. However, the manner of such crosslinking is not particularly limited and may be intramolecular crosslinking, intermolecular crosslinking, or both. The crosslinking may be, for example, a bond between silyl groups in polymer (a) (intramolecular crosslinking), or a crosslinking between a silyl group in polymer (a) and a functional group other than a silyl group in polymer (a) (for example, a hydroxyl group in a constituent unit derived from a hydroxyl group-containing (meth)acrylate, such as 2-hydroxyethyl (meth)acrylate described later) (intermolecular crosslinking).

[0050] Thus, the silane coupling agent (B) can crosslink polymer (a), but the polymerization components of the (meth)acrylic polymer (a) may also contain other crosslinkable monomers other than the silane coupling agent (B).

[0051] (Cross-linkable monomer) In crosslinkable monomers, crosslinking may occur, for example, by polymerization, or by chemical reactions (e.g., reaction with isocyanate, reaction with epoxy, hydrolysis silylation, reaction with hydrazine, reaction with aziridine, etc.).

[0052] Crosslinkable monomers may be used alone or in combination of two or more types.

[0053] The crosslinkable monomer can crosslink polymer (a), but the mode of such crosslinking is not particularly limited and can be appropriately selected depending on the type of crosslinkable monomer, and may be intramolecular crosslinking, intermolecular crosslinking, or both modes of crosslinking.

[0054] Examples of crosslinkable monomers, such as those that become crosslinkable through polymerization, include compounds having two or more polymerizable double bonds.

[0055] Examples of compounds having two or more polymerizable double bonds include di(meth)acrylates of diols {e.g., alkanediol di(meth)acrylates [e.g., ethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, etc. C 2-10[e.g., alkanediol di(meth)acrylates], polyalkylene glycol di(meth)acrylates [e.g., diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, etc.], alkylene oxide-modified alkylene glycol di(meth)acrylates [e.g., ethylene oxide-modified 1,6-hexanediol di(meth)acrylate, propylene oxide-modified neopentyl glycol di(meth)acrylate], di(meth)acrylates of aromatic diols or their alkylene oxide adducts [e.g., bisphenol A di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate], etc.], poly(meth)acrylates of polyols having 3 or more hydroxyl groups {e.g., pentaerythritol di(meth)acrylate to tetra(meth)acrylate [e.g., pentaerythritol monohydroxytri(meth)acrylate] C [e.g., pentaerythritol tetra(meth)acrylate, etc.], dipentaerythritol di or hexa(meth)acrylate [e.g., dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol (monohydroxy)penta(meth)acrylate, etc.], trimethylolpropane di or tri(meth)acrylate [e.g., trimethylolpropane tri(meth)acrylate, trimethylolpropane triethoxytri(meth)acrylate, ethylene oxide modified trimethylolpropane tri(meth)acrylate, etc.], ditrimethylolpropane di or tetra(meth)acrylate [e.g., ditrimethylolpropane tetra(meth)acrylate, etc.], glycerin di or tri(meth)acrylate [e.g., ethoxylated glycerin tri(meth)acrylate, propylene oxide modified glycerol tri(meth)acrylate, etc.] 3-10 Polymethacrylates such as poly(meth)acrylates of polyols; unsaturated hydrocarbons [e.g., alkadienes (e.g., butadiene, isoprene, chloroprene, etc.)] 4-10Examples include: alkadienes, etc.; aromatic hydrocarbons (e.g., divinylbenzene, etc.); and compounds having multiple allyl groups, such as diallyl dicarboxylates (e.g., diallyl phthalate, etc.) and triallyl isocyanurate.

[0056] Examples of crosslinkable monomers, including those that become crosslinkable through chemical reactions, include epoxy group-containing monomers, carbonyl group-containing monomers, aziridinyl group-containing monomers, and isocyanate group-containing monomers.

[0057] Examples of epoxy group-containing monomers include epoxy group-containing (meth)acrylates [e.g., glycidyl (meth)acrylate, α-methylglycidyl (meth)acrylate, glycidyloxyalkyl (meth)acrylate (e.g., 2-glycidyloxyethyl (meth)acrylate, etc.]. 2-4 Examples include alkyl (meth)acrylates, allyl glycidyl ethers, etc., but the present invention is not limited to these examples. These epoxy group-containing monomers may be used individually or in combination of two or more types.

[0058] Examples of carbonyl group-containing monomers include aldehydes having polymerizable double bonds (e.g., acrolein, formyl styrene, (meth)acryloxyl alkyl propenal, etc.), ketones having polymerizable double bonds (e.g., vinyl ethyl ketone, etc.), and carbonyl group-containing (meth)acrylates [e.g., acetonyl (meth)acrylate, diacetone (meth)acrylate, 2-hydroxypropyl (meth)acrylate acetyl acetate, butanediol-1,4-acrylate acetyl acetate, 2-(acetoacetoxy)ethyl (meth)acrylate, etc.], but the present invention is not limited to these examples. These carbonyl group-containing monomers may be used individually or in combination of two or more types.

[0059] Examples of monomers containing an aziridinyl group include (meth)acryloylaziridine and aziridinyl group-containing (meth)acrylates (e.g., 2-aziridinylethyl (meth)acrylate), but the present invention is not limited to these examples. These aziridinyl group-containing monomers may be used individually or in combination of two or more types.

[0060] Examples of isocyanate group-containing monomers include isocyanate group-containing (meth)acrylates. Examples of isocyanate group-containing (meth)acrylates include 2-acryloyloxyethyl isocyanate (trade name: "Kalenz AOI®" manufactured by Showa Denko K.K., etc.), 2-methacryloyloxyethyl isocyanate (trade name: "Kalenz MOI®" manufactured by Showa Denko K.K., etc.), 1,1-bis(acryloyloxymethyl)ethyl isocyanate (trade name: "Kalenz BEI®" manufactured by Showa Denko K.K., etc.), and 5-methacroyloxy-3-oxypentyl isocyanate (trade name: "Kalenz MOI-EG®" manufactured by Showa Denko K.K., etc.), but the present invention is not limited to these examples. These isocyanate group-containing monomers may be used individually or in combination of two or more types.

[0061] Crosslinkable monomers may be used alone or in combination of two or more types.

[0062] If the polymerization component contains a crosslinkable monomer, the proportion of the crosslinkable monomer in the total polymerization component may be, for example, 0.01 to 15% by mass, preferably 0.05 to 10% by mass, and more preferably about 0.1 to 5% by mass.

[0063] (Other monomers) The polymerization components of the (meth)acrylic polymer may include monomers other than the reactive emulsifier (A) and the silane coupling agent (B) (and also crosslinkable monomers). Other representative monomers include aliphatic (meth)acrylates.

[0064] Examples of aliphatic (meth)acrylates include alkyl (meth)acrylates [e.g., methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, sec-butyl (meth)acrylate, amyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, n-lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, etc.]. 1-20 Alkyl (meth)acrylate], alkoxyalkyl (meth)acrylate [e.g., alkoxyalkyl (meth)acrylate (e.g., C of 2-methoxyethyl (meth)acrylate] 1-12 Alkoxy C 1-12 Examples include alkyl methacrylates, etc.

[0065] Aliphatic (meth)acrylates may be used alone or in combination of two or more types.

[0066] Among these aliphatic (meth)acrylates, C13 1-12 Alkyl (meth)acrylate (for example, C 1-8 Alkyl (meth)acrylates are preferred, and in particular, 2-ethylhexyl (meth)acrylate is preferred.

[0067] In the polymerization component, the proportion of aliphatic (meth)acrylate depends on the types of other monomers, but the proportion of aliphatic (meth)acrylate in the total polymerization component may be, for example, 10 to 90% by mass, preferably 20 to 90% by mass, more preferably 25 to 80% by mass, and particularly preferably about 30 to 80% by mass.

[0068] In particular, when the polymerization component contains 2-ethylhexyl (meth)acrylate, the proportion of 2-ethylhexyl (meth)acrylate in the total polymerization component may be, depending on the types of other monomers, for example, 10% by mass or more (e.g., 10-90% by mass), preferably 20% by mass or more (e.g., 20-90% by mass), more preferably 25% by mass or more (e.g., 25-80% by mass), and especially preferably 30% by mass or more (e.g., 30-80% by mass).

[0069] Other monomers besides aliphatic (meth)acrylates include, for example, alicyclic monomers (monomers containing alicyclic groups), hydroxyl group-containing (meth)acrylates, aromatic monomers (monomers containing aromatic groups), acid group-containing monomers (or anionic group-containing monomers), fluorine atom-containing monomers, nitrogen atom-containing monomers, UV-absorbing monomers, and hindered amine monomers (UV-stable monomers).

[0070] (Alipid monomers) As alicyclic monomers, alicyclic structures (for example, C 4-20 Cycloalkyl groups, preferably C 4-10 Examples include monomers having a cycloalkyl group. Specific examples of alicyclic monomers include alicyclic (meth)acrylates [e.g., cycloalkyl (meth)acrylates (e.g., cyclohexyl (meth)acrylates, etc.] 4-20 Cycloalkyl (meth)acrylate, preferably C 4-10Cycloalkyl (meth)acrylates), cycloalkylalkyl (meth)acrylates (e.g., cyclohexylmethyl (meth)acrylate, cyclohexylethyl (meth)acrylate, cyclohexylpropyl (meth)acrylate, 4-methylcyclohexylmethyl (meth)acrylate, etc.) 4-10 Cycloalkyl C 1-4 Examples include alkyl (meth)acrylates and cross-linked cyclic (meth)acrylates (e.g., isobornyl (meth)acrylate, adamantyl (meth)acrylate, etc.).

[0071] Among alicyclic monomers, C 4-20 Cycloalkyl (meth)acrylates are preferred, C 4-10 Cycloalkyl (meth)acrylates are more preferred, and isobornyl (meth)acrylates and cyclohexyl (meth)acrylates are even more preferred.

[0072] Alicyclic monomers may be used individually or in combination of two or more types.

[0073] When the polymerization component contains alicyclic monomers, the proportion of alicyclic monomers in the total polymerization component may be, for example, 5 to 80% by mass, preferably 10 to 70% by mass, more preferably 15 to 65% by mass, and particularly preferably about 20 to 60% by mass.

[0074] Furthermore, if the polymerization components contain aliphatic (meth)acrylates and alicyclic monomers, the proportion of these may be approximately 95 / 5 to 5 / 95 (for example, 90 / 10 to 10 / 90), preferably 80 / 20 to 20 / 80, and even more preferably 80 / 20 to 40 / 60.

[0075] (Hydroxyl group-containing (meth)acrylate) Examples of hydroxyl group-containing (meth)acrylates include hydroxyalkyl (meth)acrylates [e.g., 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc.]. 2-10 Alkyl (meth)acrylate, preferably hydroxy C 2-6 Alkyl (meth)acrylate, more preferably hydroxy C 2-4 [Alkyl (meth)acrylates, etc.], (meth)acrylates of polyols having 3 or more hydroxyl groups [e.g., tri or hexahydroxy C such as glycerin mono(meth)acrylate] 3-10 Examples include polyol (meth)acrylates.

[0076] Hydroxyl group-containing (meth)acrylates may be used alone or in combination of two or more types.

[0077] Among hydroxyl group-containing (meth)acrylates, 2-hydroxyethyl (meth)acrylate and glycerin mono(meth)acrylate are preferred, with 2-hydroxyethyl (meth)acrylate being more preferred.

[0078] When the polymerization component contains hydroxyl group-containing (meth)acrylate, the proportion of hydroxyl group-containing (meth)acrylate in the total polymerization component may be, for example, 0.1 to 20% by mass, preferably 0.3 to 10% by mass, more preferably 0.5 to 8% by mass, and particularly preferably about 1 to 5% by mass.

[0079] Furthermore, if the polymerization component contains aliphatic (meth)acrylate and / or alicyclic monomers, and hydroxyl group-containing (meth)acrylate, the proportion of hydroxyl group-containing (meth)acrylate may be, for example, 0.1 to 20 parts by mass, preferably 0.3 to 15 parts by mass, more preferably 0.5 to 10 parts by mass, and particularly preferably 1 to 8 parts by mass, per 100 parts by mass of aliphatic (meth)acrylate and / or alicyclic monomers.

[0080] (Aromatic monomers) Examples of aromatic monomers include styrene monomers [e.g., styrene, α-alkylstyrene (e.g., α-methylstyrene, etc.)]. 1-4 Alkylstyrene), alkylstyrene (for example, vinyltoluene, etc.) 1-4 Alkylstyrene, halostyrene (e.g., chlorostyrene), aromatic (meth)acrylates (e.g., aryl (meth)acrylates (e.g., phenyl (meth)acrylate)), C 6-10 Aryl (meth)acrylates), aralkyl (meth)acrylates (for example, benzyl (meth)acrylate, phenethyl (meth)acrylate, etc.) 6-10 Aryl C 1-4 Alkyl (meth)acrylates), aryloxyalkyl methacrylates (e.g., C phenoxyethyl methacrylate) 6-10 Aryloxy C 1-4 Examples include alkyl methacrylates, etc.

[0081] Among aromatic monomers, styrene monomers are preferred.

[0082] Aromatic monomers may be used individually or in combination of two or more types.

[0083] When the polymerization component contains aromatic monomers, the proportion of aromatic monomers in the total polymerization component may be, for example, 0.1 to 50% by mass, preferably 0.5 to 40% by mass, and more preferably 1 to 35% by mass (for example, 10 to 35% by mass).

[0084] (Acid group-containing monomer) Examples of acid group-containing monomers (anionic group-containing monomers) include carboxylic acid group-containing monomers [for example, unsaturated monocarboxylic acids (e.g., aliphatic unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid), unsaturated dicarboxylic acids (e.g., aliphatic unsaturated monocarboxylic acids such as maleic acid and fumaric acid)], and sulfonic acid group-containing monomers [for example, styrene monomers (e.g., styrene sulfonic acid)]. Furthermore, the acid group-containing monomer may be anionized (or form a salt).

[0085] Acid group-containing monomers may be used individually or in combination of two or more types.

[0086] When the polymerization component contains an acid group-containing monomer, the proportion of the acid group-containing monomer in the total polymerization component may be, for example, 0.01 to 10% by mass, preferably 0.02 to 5% by mass, and more preferably 0.05 to 3% by mass.

[0087] (Fluorine atom-containing monomer) Examples of fluorine atom-containing monomers include fluorine atom-containing acrylic monomers [e.g., fluoroalkyl (meth)acrylates (e.g., trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, etc., fluoro-C]. 1-10 Alkyl (meth)acrylate, preferably fluoroC 2-6 Examples include alkyl (meth)acrylates, etc.

[0088] Fluorine atom-containing monomers may be used alone or in combination of two or more types.

[0089] When the polymerization component contains a fluorine atom-containing monomer, the proportion of the fluorine atom-containing monomer in the total polymerization component may be, for example, 0.01 to 10% by mass, preferably 0.02 to 5% by mass, and more preferably 0.03 to 3% by mass.

[0090] (Nitrogen atom-containing monomer) Examples of nitrogen atom-containing monomers include (meth)acrylamide compounds {e.g., (meth)acrylamide, N-substituted (meth)acrylamide [e.g., N-alkyl(meth)acrylamide (e.g., N,N-dimethyl(meth)acrylamide, etc., N,N-diC 1-4 Alkyl (meth)acrylamide; N,N-dimethylaminopropyl (meth)acrylamide, etc.), etc., nitrogen atom-containing (meth)acrylate compounds {e.g., N-substituted aminoalkyl (meth)acrylate [e.g., dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, etc., N,N-diC 1-4 Alkylamino C 2-4 Examples include alkyl (meth)acrylates, etc.

[0091] Nitrogen atom-containing monomers may be used individually or in combination of two or more types.

[0092] When the polymerization component contains nitrogen atom-containing monomers, the proportion of nitrogen atom-containing monomers in the total polymerization component may be, for example, 0.01 to 10% by mass, preferably 0.02 to 5% by mass, and more preferably 0.03 to 3% by mass.

[0093] (UV-absorbing monomer) Examples of ultraviolet-absorbing monomers (monomers having ultraviolet-absorbing groups) include benzotriazole-based ultraviolet-absorbing monomers and benzophenone-based ultraviolet-absorbing monomers.

[0094] Benzotriazole-based UV-absorbing monomers include benzotriazole-based UV absorbers having polymerizable groups (e.g., (meth)acryloyl groups), such as 2-[2'-hydroxy-5'-(meth)acryloyloxymethylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxyethylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxymethylphenyl]-5-tert-butyl-2H-benzotriazole, and 2-[2'-hydroxy C-5'-(meth)acryloylaminomethyl-5'-tert-octylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxypropylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxyhexylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-3'-tert-butyl-5'-(meth)acryloyloxyethylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-3'-tert-butyl-5'-(meth)acryloyloxyethylphenyl]-5-chloro-2H-benzotriazole, 2-[2'-hydroxy-5'-ter Examples include t-butyl-3'-(meth)acryloyloxyethylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxyethylphenyl]-5-chloro-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxyethylphenyl]-5-cyano-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxyethylphenyl]-5-tert-butyl-2H-benzotriazole, and 2-[2'-hydroxy-5'-(β-(meth)acryloyloxyethoxy)-3'-tert-butylphenyl]-4-tert-butyl-2H-benzotriazole.

[0095] Examples of benzophenone-based UV-absorbing monomers include benzophenone-based UV absorbers having polymerizable groups (e.g., (meth)acryloyl groups), such as 2-hydroxy-4-(meth)acryloyloxybenzophenone, 2-hydroxy-4-[2-hydroxy-3-(meth)acryloyloxy]propoxybenzophenone, 2-hydroxy-4-[2-(meth)acryloyloxy]ethoxybenzophenone, 2-hydroxy-4-[3-(meth)acryloyloxy-2-hydroxypropoxy]benzophenone, and 2-hydroxy-3-tert-butyl-4-[2-(meth)acryloyloxy]butoxybenzophenone.

[0096] UV-absorbing monomers may be used alone or in combination of two or more types.

[0097] When the polymerization component contains an ultraviolet-absorbing monomer, the proportion of the ultraviolet-absorbing monomer in the total polymerization component may be, for example, 0.01 to 10% by mass, preferably 0.02 to 5% by mass, and more preferably 0.03 to 3% by mass.

[0098] (Hindered amine monomers) Examples of hindered amine monomers (UV-stable monomers, light stabilizers with polymerizable groups, light-stable monomers) include 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4-(meth)acryloyl-1-methoxy-2,2,6,6-tetramethylpiperidine, 4-cyano-4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, and 1-(meth)acryloyl-4-(meth)acrylo Examples include ylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoylamino-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 1-(meth)acryloyl-4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, and 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine.

[0099] Hindered amine monomers may be used alone or in combination of two or more.

[0100] When the polymerization component contains a hindered amine monomer, the proportion of the hindered amine monomer in the total polymerization component may be, for example, 0.01 to 20% by mass, preferably 0.05 to 10% by mass, and more preferably about 0.1 to 5% by mass.

[0101] Among the other monomers mentioned above, alicyclic monomers [for example, C 4-20 Cycloalkyl (meth)acrylate (preferably, C 4-10Cycloalkyl (meth)acrylates, more preferably isobornyl (meth)acrylates, cyclohexyl (meth)acrylates, etc.) and aromatic monomers {e.g., styrene monomers [e.g., styrene, α-alkylstyrene (e.g., α-C 1-4 Alkylstyrene (for example, C 1-4 It is preferable to include one or more selected from alkylstyrene, halostyrene (e.g., chlorostyrene), etc., and in particular, it is preferable to include one or more selected from cyclohexyl methacrylate and styrene.

[0102] The other monomers exemplified above may be used individually or in combination of two or more types.

[0103] As will be described later, emulsions can usually be prepared by a reaction in the presence of an emulsifier. The emulsifier may be a reactive emulsifier (A), or it may contain a reactive emulsifier (A) in addition to other emulsifiers (surfactants) that do not belong to the category of reactive emulsifier (A).

[0104] Other emulsifiers may include any emulsifier that does not fall under the category of reactive emulsifier (A), such as anionic emulsifiers, nonionic emulsifiers, cationic emulsifiers (e.g., alkylammonium salts such as decylammonium chloride), and amphoteric emulsifiers (e.g., betaine ester type emulsifiers).

[0105] Examples of anionic emulsifiers include alkyl sulfate salts such as ammonium dodecyl sulfate and sodium dodecyl sulfate; alkyl sulfonate salts such as ammonium dodecyl sulfonate and sodium dodecyl sulfonate; alkylaryl sulfonate salts such as ammonium dodecylbenzene sulfonate and sodium dodecylnaphthalene sulfonate; polyoxyethylene alkyl sulfate salts; polyoxyethylene alkylaryl sulfate salts; polyoxyethylene alkyl ether sulfates; dialkyl sulfosuccinates; aryl sulfonic acid-formaldehyde condensates; and fatty acid salts such as ammonium laurylate and sodium stearate.

[0106] Examples of nonionic emulsifiers include polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers, condensates of polyethylene glycol and polypropylene glycol, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, fatty acid monoglycerides, and condensates of ethylene oxide and aliphatic amines.

[0107] Other emulsifiers include polymer emulsifiers. Examples of polymer emulsifiers include anionic emulsifiers (poly(meth)acrylates such as sodium polyacrylate), nonionic emulsifiers (polyhydroxyalkyl(meth)acrylates such as polyvinyl alcohol, polyvinylpyrrolidone, and polyhydroxyethyl acrylate), and polymers that use one or more monomers from among the monomers that make up these polymers as copolymer components.

[0108] Furthermore, other emulsifiers may be those having a reactive group (or polymerizable group) (reactive emulsifier) ​​from the viewpoint of coating film properties, etc. If the emulsion contains other reactive emulsifiers, these other reactive emulsifiers may be polymerization components of the (meth)acrylic polymer (a) together with the reactive emulsifier (A).

[0109] Other reactive emulsifiers include, for example, anionic emulsifiers [e.g., propenyl-alkyl sulfosuccinate salts, (meth)acrylate polyoxyethylene sulfonate salts, (meth)acrylate polyoxyethylene phosphate salts (e.g., Sanyo Chemical Industries, Ltd., trade name: Eleminol RS-30, etc.)], polyoxyethylene alkylpropenylphenyl ether sulfonate salts (e.g., Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon HS-10, etc.)], allyloxymethylalkyloxypolyoxyethylene sulfonate salts (e.g., Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon KH-10, etc.)], propenylnonylphenyloxypolyoxyethylene sulfonate salts (e.g., Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10, etc.)], allyloxymethylnonylphenoxyethyl hydroxypolyoxyethylene sulfonate salts (e.g., ADEKA Corporation, Examples include: product name: Adekarya Soap SE-10, allyloxymethyl alkoxyethyl hydroxypolyoxyethylene sulfate salt [for example, manufactured by ADEKA Corporation, product names: Adekarya Soap SR-10, SR-30, etc.], bis(polyoxyethylene polycyclic phenyl ether) methacrylate sulfonate salt [for example, manufactured by Nippon Emulsifier Co., Ltd., product name: Antox MS-60, etc.], nonionic emulsifiers [for example, allyloxymethyl alkoxyethyl hydroxypolyoxyethylene [for example, manufactured by ADEKA Corporation, product name: Adekarya Soap ER-20, etc.], polyoxyethylene alkylpropenylphenyl ether [for example, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon RN-20, etc.], allyloxymethyl nonylphenoxyethyl hydroxypolyoxyethylene [for example, manufactured by ADEKA Corporation, product name: Adekarya Soap NE-10, etc.], etc.].

[0110] Other emulsifiers may be used alone or in combination of two or more types.

[0111] Among these other emulsifiers, anionic emulsifiers, particularly anionic reactive emulsifiers, may be preferably used.

[0112] If the emulsion contains other emulsifiers, the proportion of other emulsifiers in the total polymerization components may be, for example, 30% by mass or less (e.g., 0.01 to 30% by mass), preferably 20% by mass or less (e.g., 0.01 to 20% by mass), more preferably 10% by mass or less (e.g., 0.01 to 10% by mass), and particularly preferably 5% by mass or less (e.g., 0.01 to 5% by mass).

[0113] The proportion of reactive emulsifier (A) in the total emulsifier may be, for example, 10% by mass or more (e.g., 10-100% by mass, 10-90% by mass), preferably 40% by mass or more (e.g., 40-100% by mass, 40-90% by mass), more preferably 70% by mass or more (e.g., 70-100% by mass, 70-90% by mass), particularly preferably 90% by mass or more (e.g., 90-100% by mass), and most preferably 100% by mass.

[0114] The emulsion may have a single-layer structure (consisting of only one layer) or a multi-layer structure (or core-shell structure) (consisting of an inner layer, or an outer layer (outermost layer) and an inner layer).

[0115] If the emulsion has a multilayer structure, the number of layers may be two or more, for example, 2 to 6, preferably 2 to 5, more preferably 2 to 4 (for example, 2 to 3), and especially 3.

[0116] If the emulsion has a multilayer structure, at least one of the outer layer (shell) and inner layer (core) must be composed of (meth)acrylic polymer (a) (emulsion), and the inner layer and outer layer may be composed of different polymers (resins). The (meth)acrylic polymer (a) (emulsion) may constitute either an outer layer or an inner layer, but it is preferable that it constitutes at least an outer layer. Furthermore, if either the outer or inner layer is composed of a polymer (emulsion) other than (meth)acrylic polymer (a), the polymerization component of such polymer can be selected from the monomers exemplified above (for example, other monomers exemplified above).

[0117] Furthermore, the multilayer structure may be composed of a hard layer and a soft layer (relatively composed). In such cases, either the outer layer or the inner layer may be the hard layer; that is, the outer layer may be the hard layer and the inner layer may be the soft layer, or the outer layer may be the soft layer and the inner layer may be the hard layer. Furthermore, if the inner layer is composed of multiple layers, hard and soft layers may be formed between the multiple inner layers.

[0118] The mass ratio of the polymer constituting the inner layer to the polymer constituting the outer layer may be, from the viewpoint of improving the water resistance of the coating film, for example, 95:5 to 5:95 (for example, 90:10 to 10:90), preferably 88:12 to 12:88 (for example, 85:15 to 15:85), or 95:5 to 20:80 (for example, 90:10 to 30:70, preferably 88:12 to 40:60).

[0119] In particular, if the emulsion has a three-layer structure, the proportion of the first layer may be approximately 20-70% by mass (e.g., 30-60% by mass) of the entire emulsion, the proportion of the second layer may be approximately 20-70% by mass (e.g., 30-60% by mass), and the proportion of the third layer may be approximately 20-70% by mass (e.g., 30-60% by mass).

[0120] The glass transition temperature of the (meth)acrylic polymer (a) constituting the emulsion may be, for example, -40°C or higher (e.g., -40 to 80°C, -40 to 40°C, etc.), preferably -30°C or higher (e.g., -30 to 80°C, -30 to 40°C, etc.), and more preferably -25°C or higher (e.g., -25 to 80°C, -25 to 40°C, etc.). Furthermore, in the case of a multilayer emulsion, the glass transition temperature of the entire polymer constituting the multilayer emulsion may be within the range of the above examples.

[0121] Furthermore, the glass transition temperature is determined using the glass transition temperature of the monomer homopolymer used in the monomer components that make up the polymer. Formula (I): 1 / Tg=Σ(Wm / Tgm) / 100 (I) [In the formula, Wm represents the content (mass%) of monomer m in the monomer components constituting the polymer, and Tgm represents the glass transition temperature (absolute temperature: K) of the monomer m homopolymer.] The temperature may also be determined based on Fox's formula, which is expressed as follows:

[0122] Furthermore, if the emulsion has a multilayer structure, the glass transition temperature of the entire polymer constituting the multilayer emulsion is the glass transition temperature determined from the mass fraction of each monomer in all monomer components used in multi-stage emulsion polymerization and the corresponding glass transition temperatures of the monomer homopolymers.

[0123] The glass transition temperatures of homopolymers are, for example, -70°C for 2-ethylhexyl acrylate, 83°C for cyclohexyl methacrylate, 100°C for styrene, 70°C for γ-methacryloxypropyltrimethoxysilane, 55°C for 2-hydroxyethyl methacrylate, 105°C for methyl methacrylate, 130°C for methacrylic acid, 107°C for tert-butyl methacrylate, approximately 130°C for 1,2,2,6,6-pentamethylpiperidyl methacrylate, 77°C for diacetone acrylamide, 55°C for glycerin monomethacrylate, 20°C for n-butyl methacrylate, and -56°C for n-butyl acrylate.

[0124] Furthermore, for monomers whose glass transition temperature is unknown, such as special monomers and polyfunctional monomers, if the total amount of monomers with unknown glass transition temperatures in the monomer component is 10% by mass or less, the glass transition temperature may be determined using only monomers whose glass transition temperatures are known.

[0125] If the total amount of monomers whose glass transition temperature is unknown exceeds 10% by mass fraction, the glass transition temperature of the polymer may be determined by differential scanning calorimetry (DSC), differential calorimetry (DTA), thermomechanical analysis (TMA), etc.

[0126] The weight-average molecular weight of the (meth)acrylic polymer (a) constituting the emulsion may be, for example, 100,000 or more, preferably 300,000 or more, more preferably 550,000 or more, and particularly preferably 600,000 or more, from the viewpoint of improving the water resistance of the coating film.

[0127] Furthermore, while there is no particular upper limit to the weight-average molecular weight of the (meth)acrylic polymer (a), it is preferable that it be 5 million or less, for example, from the viewpoint of improving film-forming properties.

[0128] The weight-average molecular weight may be measured (in polystyrene equivalent) using, for example, gel permeation chromatography [e.g., Tosoh Corporation, catalog number: HLC-8120GPC, using TSKgel G-5000HXL and TSKgel GMHXL-L columns in series].

[0129] The average particle size of the emulsion particles is not particularly limited, but may be, for example, 50 nm or more, preferably 100 nm or more, or, from the viewpoint of coating film properties, may be, for example, 300 nm or less, preferably 250 nm or less. The average particle size of the emulsion particles is typically 50 to 300 nm (for example, 60 to 250 nm), preferably around 100 to 250 nm.

[0130] Furthermore, the average particle size of the emulsion particles may be the volume-average particle size measured using a particle size distribution analyzer (Particle Sizing Systems, product name: NICOMP Model 380) that employs the dynamic light scattering method.

[0131] The amount of solid content (non-volatile content) of particles (or solids) in the emulsion is preferably 30% by mass or more, more preferably 40% by mass or more, from the viewpoint of productivity, and may be preferably 70% by mass or less, more preferably 60% by mass or less, from the viewpoint of improving handlingability.

[0132] Furthermore, the non-volatile content of particles in an emulsion is determined, for example, by weighing 1 g of emulsion, drying it in a hot air dryer at 110°C for 1 hour, and considering the resulting residue as the non-volatile content. Formula: [Non-volatile content in emulsion (mass %)] = ([Mass of residue] ÷ [1g of emulsion]) × 100 It can be determined based on this.

[0133] The minimum film-forming temperature of the emulsion may be, for example, 60°C or lower, preferably 50°C or lower, and more preferably 40°C or lower, from the viewpoint of improving film-forming properties. The minimum film-forming temperature of an emulsion can be adjusted, for example, by controlling the glass transition temperature of the entire emulsion particles or the glass transition temperature of the outermost layer.

[0134] In this specification, the minimum film-forming temperature of the emulsion can be determined, for example, by applying the resin emulsion to a glass plate placed on a thermal gradient tester with an applicator to a thickness of 0.2 mm, and determining the temperature at which cracks occur.

[0135] The polymer content in the emulsion (the content of (meth)acrylic polymer (a), or in the case of a multilayer structure, the total content of polymers constituting the inner and outer layers) may be, for example, 20% by mass or more (e.g., 25 to 100% by mass), preferably 30% by mass or more (e.g., 35 to 90% by mass), and more preferably 40% by mass or more (e.g., 45 to 85% by mass), from the viewpoint of coating film properties and other factors.

[0136] (Method for manufacturing emulsion) Emulsions can be obtained by emulsion polymerization of polymerization components (monomer components) in a solvent.

[0137] Examples of solvents include water, water-containing solvents [water and alcohol (methanol, ethanol, etc.)] 1-4 Examples of aqueous solvents include mixed solvents with alcohols, etc. The solvent may be used individually or in combination of two or more types.

[0138] Methods for emulsion polymerization of monomer components include, for example, a method of polymerization by mixing (dropping, etc.) monomer components into a solvent (solution) containing an emulsifier, or a method of polymerization by mixing (dropping, etc.) pre-emulsified monomer components into a solvent; however, the present invention is not limited to such methods.

[0139] The amount of solvent (medium) should be set appropriately, taking into consideration the amount of non-volatile components contained in the resulting emulsion.

[0140] Polymerization may be carried out in the presence of a polymerization initiator. Examples of polymerization initiators include azo compounds such as azobisisobutyronitrile, 2,2-azobis(2-methylbutyronitrile), 2,2-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-diaminopropane)hydrochloride, 4,4-azobis(4-cyanovaleric acid), and 2,2-azobis(2-methylpropionamidine); persulfates such as potassium persulfate; and peroxides such as hydrogen peroxide, benzoyl peroxide, parachlorobenzoyl peroxide, lauroyl peroxide, and ammonium peroxide. Polymerization initiators may be used individually or in combination of two or more.

[0141] When a polymerization initiator is used, the amount of polymerization initiator per 100 parts by mass of polymerization component is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, from the viewpoint of increasing the polymerization rate and reducing the amount of unreacted monomer components remaining, and preferably 1 part by mass or less, more preferably 0.5 parts by mass or less, from the viewpoint of coating film properties, etc.

[0142] The method of adding the polymerization initiator is not particularly limited, but examples include batch addition, divided addition, and continuous dropwise addition. Furthermore, from the viewpoint of accelerating the completion of the polymerization reaction, a portion of the polymerization initiator may be added to the reaction vessel before or after the completion of the addition of polymerization components to the reaction system.

[0143] Furthermore, in order to promote the decomposition of the polymerization initiator, appropriate amounts of a decomposing agent for the polymerization initiator, such as a reducing agent like sodium bisulfite or a transition metal salt like ferrous sulfate, may be added to the reaction system.

[0144] Furthermore, additives such as chain transfer agents (e.g., tert-dodecyl mercaptan), pH buffers, chelating agents, and film-forming aids may be present in the reaction system as needed.

[0145] The atmosphere during polymerization is not particularly limited, but from the viewpoint of polymerization efficiency, an inert gas such as nitrogen gas may be used.

[0146] The polymerization temperature is not particularly limited, but may be, for example, 50 to 100°C, preferably 60 to 95°C. The polymerization temperature may be constant or may be changed during the polymerization reaction.

[0147] The polymerization time is not particularly limited and can be set appropriately according to the progress of the polymerization reaction, but it may be, for example, 1 hour or more (e.g., 1 to 24 hours), preferably 2 to 12 hours (e.g., 2 to 9 hours).

[0148] Furthermore, multilayer emulsions can be obtained by carrying out the emulsion polymerization described above in multiple steps.

[0149] <Composition> The present invention also includes compositions comprising an emulsion of a (meth)acrylic polymer having at least one reactive emulsifier (A) having multiple aromatic groups as a polymerization component, and a urethane-associated thickener. The compositions of the present invention can be used, in particular, for paints. In such a composition, the reactive emulsifier (A) described above can be used as the reactive emulsifier (A).

[0150] Furthermore, the composition may contain the monomers exemplified above (for example, silane coupling agent (B), crosslinkable monomer, other monomers, etc.) as polymerization components of the (meth)acrylic polymer.

[0151] Furthermore, the (meth)acrylic polymer in the composition may be the (meth)acrylic polymer (a) described above, and the emulsion in the composition may be the emulsion described above.

[0152] As a urethane-associated thickener, for example, a urethane-based resin can be suitably used. The urethane-based resin is preferably water-soluble.

[0153] It is preferable that urethane resins have both hydrophobic parts (hydrophobic groups) and hydrophilic parts (hydrophilic groups).

[0154] The bonding site of the hydrophobic group in the urethane resin is not particularly limited. The hydrophobic group may be located at one end of the urethane resin, or at both ends, and it is preferable that it be located at both ends. Furthermore, hydrophobic groups can act as aggregation sites. For example, in a solvent (water, or an aqueous solvent containing water), the (meth)acrylic polymer (a) emulsion can be thickened by the association (physical bonding) of hydrophobic groups (especially terminal hydrophobic groups) with the surface of the emulsion particles of the (meth)acrylic polymer (a), and / or by the association of hydrophobic groups with each other.

[0155] Examples of hydrophobic groups include hydrocarbon groups (e.g., C 1-30 Aliphatic hydrocarbon group, C 3-30 Examples include aliphatic hydrocarbon groups, etc.

[0156] The bonding site of the hydrophilic group in the urethane resin is not particularly limited, and the hydrophilic group may be present in the main chain of the urethane polymer or in the side chains.

[0157] The hydrophilic parts (hydrophilic groups) are not particularly limited, but examples include parts having ether bonds (e.g., oxyalkylene units such as polyoxyethylene). The parts having ether bonds may be, for example, units derived from polyols, which are structural units of urethane resins.

[0158] The urethane-associated thickener may be one that is readily available commercially.

[0159] Examples of urethane-associated thickeners include Adekanol UH-420, Adekanol UH-438, and Adekanol UH-450VF (all manufactured by ADEKA Corporation, trade names), but the present invention is not limited to these examples. Among these, Adekanol UH-420 is preferred. Urethane-associated thickeners may be used individually or in combination of two or more types.

[0160] In the composition, the mass ratio of (meth)acrylic polymer to urethane-associated thickener may be, for example, 100:0.01 to 100:1, preferably 100:0.1 to 100:0.8, and more preferably 100:0.15 to 100:0.5. In the present invention, by using the above-mentioned reactive emulsifier (A), paint can be efficiently formed even if the ratio of the thickener to the (meth)acrylic polymer (active ingredient) is relatively small.

[0161] The composition may contain other thickeners besides urethane-associated thickeners. Other thickeners may include, for example, acrylic resins that dissolve in water (area-soluble) upon the addition of a base [for example, acrylic resins containing at least units derived from (meth)acrylic acid and alkyl (meth)acrylate (for example, methyl (meth)acrylate)]. Such acrylic resins can thicken a solution by dissolving in an alkaline solution. Such acrylic resins may also have association sites (for example, hydrophobic groups in the urethane resins described above).

[0162] Other thickeners may be commercially readily available. Other examples of thickening agents include Acryset WR-507 and Acryset WR-650 (both manufactured by Nippon Shokubai Co., Ltd., trade names), but the present invention is not limited to these examples. Other thickening agents may be used individually or in combination of two or more.

[0163] If the composition contains other thickeners, the mass ratio of the urethane-associated thickener to the other thickener may be, for example, 100:1 to 100:100, preferably 100:5 to 100:90, and more preferably 100:10 to 100:80.

[0164] The viscosity of the composition may be, for example, 1,000 to 20,000 mPa·s, preferably 1,500 to 10,000 mPa·s, and more preferably 2,000 to 8,000 mPa·s, as measured by a BH-type viscometer at a rotation speed of 20 rpm and 25°C.

[0165] The composition may contain a solvent, or it may be a composition in which the emulsion and the thickener are dispersed (or dissolved) in the solvent.

[0166] As the solvent, the solvents described above can be used, preferably aqueous solvents such as water or water-containing solvents [for example, a mixed solvent containing water and alcohol (lower alcohols such as methanol and ethanol)]. In particular, the composition may be an aqueous composition in which an emulsion and a thickening agent are dispersed (or dissolved) in an aqueous solvent.

[0167] In a composition containing a solvent, the total proportion of the emulsion and the thickener can be appropriately selected depending on the application, but for example, it may be 0.1 to 95% by mass, preferably 1 to 90% by mass, and more preferably about 3 to 80% by mass.

[0168] The composition may contain other components besides the aforementioned components (e.g., emulsion and thickener). Other components include, for example, pigments (such as those described later), pigment dispersants, preservatives, UV absorbers, light stabilizers, film-forming aids, thickeners, surface modifiers, preservatives and antifungal agents, leveling agents, antifreeze agents, wetting agents, pH adjusters, and defoaming agents. These ingredients may be used individually or in combination of two or more.

[0169] The method for producing the composition is not particularly limited, and for example, it can be produced by mixing an emulsion with a thickener (and, if necessary, a solvent or other components).

[0170] (Uses of emulsions and compositions) The emulsions and compositions of the present invention are particularly suitable for use as paints (coatings). Such emulsions and compositions may be used, for example, for surface finishing of substrates made of various materials (e.g., metal, glass, porcelain, concrete, siding boards, resins, etc.).

[0171] The emulsions and compositions of the present invention are particularly suitable for use as topcoats (or top coatings, such as topcoats for interior materials (building materials) and exterior materials).

[0172] Examples of exterior materials include various building materials (e.g., inorganic building materials such as flexible boards, calcium silicate boards, gypsum slag perlite boards, wood chip cement boards, precast concrete boards, ALC boards, and gypsum boards; and ceramic building materials such as roof tiles and exterior wall materials). Ceramic building materials can be obtained, for example, by adding inorganic fillers and fibrous materials to a hydraulic adhesive that serves as a raw material for an inorganic hardened body, molding the resulting mixture, curing the resulting molded body, and allowing it to harden.

[0173] The surface of such exterior materials (building materials) is usually coated with a topcoat (water-based paint) to impart a desired design. More specifically, the topcoat or topcoat (water-based paint) is used as a paint (architectural / exterior paint) to protect the building from external environmental factors such as sunlight and wind and rain, and to enhance the aesthetic appearance and design of the building. The composition of the present invention can be suitably used as such a topcoat or topcoat (water-based paint).

[0174] In particular, it can be used as an exterior paint that is applied directly to the exterior walls (exterior materials) of buildings and dried and hardened in the natural environment (room temperature drying). The paint formed from the emulsion or composition of the present invention exhibits excellent water resistance in the resulting coating film, and therefore can achieve sufficient coating film strength even when used as an exterior coating.

[0175] The surface coating formed using the aforementioned exterior paint can take on various forms, from transparent to tinted translucent to tinted opaque. However, tinted opaque coatings are particularly common, often used to conceal the underlying coating layer or the old topcoat coating layer formed on the exterior material (for renovation purposes). Therefore, the paint composition (paint) may contain a pigment.

[0176] The pigment is not particularly limited, and any known pigment can be used. The pigment may be a coloring agent or an extender (bulking agent). Typical pigments include, for example, inorganic pigments (e.g., inorganic coloring pigments such as titanium dioxide, iron oxide, aluminum, and pearl pigments), organic pigments (e.g., organic coloring pigments such as quinacridone, anthraquinone, perylene, diketopyrrolopyrrole, benzimidazolone, isoindolinone, anthrapyrimidine, phthalocyanine, surene, dioxazine, and carbon black), and extender pigments (e.g., calcium carbonate, barium sulfate, kaolin, mica, and talc). Pigments may be used individually or in combination of two or more types.

[0177] In particular, it is preferable to use at least titanium dioxide to improve color opacity and achieve a high gloss on the coating surface. The amount of pigment may be, for example, 5 to 70 parts by mass, preferably 7 to 65 parts by mass, and more preferably 10 to 60 parts by mass, per 100 parts by weight of the solid content of the polymer component (or emulsion) in the coating film after drying.

[0178] When the composition of the present invention is used as a paint (coating), it may be applied as a single layer or as two or more layers. When applied as two or more layers, only some of the layers may be formed with the composition of the present invention, or all of the layers may be formed with the composition of the present invention. Examples of layering include applying a first layer (e.g., an undercoat layer) of paint to a substrate that has been treated with a primer or sealer, drying it, and then applying a second layer (e.g., a topcoat layer) of paint and drying it, but the present invention is not limited to such methods. When applying the paint, for example, a spray, roller, brush, trowel, etc. can be used. [Examples]

[0179] The present invention will now be described in more detail based on examples, but the present invention is not limited to these examples. In the following examples, "parts" means "parts by mass".

[0180] (Example 1) 475 parts of deionized water were placed in a flask equipped with a dropping funnel, stirrer, nitrogen inlet tube, thermometer, and reflux condenser. A dropper pre-emulsion was prepared in a dropping funnel consisting of 465 parts deionized water, 120 parts 25% aqueous solution of emulsifier (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon AR-10), 333 parts 2-ethylhexyl acrylate (2EHA), 460 parts methyl methacrylate (MMA), 200 parts styrene (St), 5 parts 2-hydroxyethyl methacrylate (HEMA), and 2 parts silyl group-containing monomer (product name: KBM-503). 100 parts of this pre-emulsion was added to a flask, and the temperature was raised to 80°C while slowly blowing in nitrogen gas. Polymerization was then initiated by adding 60 parts 5% aqueous solution of potassium persulfate to the flask.

[0181] Next, the remaining pre-emulsion for dropwise addition was uniformly added to the flask dropwise over a period of 180 minutes. After the addition was complete, the contents of the flask were maintained at 80°C for 60 minutes, and 25% aqueous ammonia was added to the flask to bring the pH to 8-10, thereby ending the polymerization reaction.

[0182] After cooling the resulting reaction solution to room temperature, a resin emulsion was obtained by filtering it through a 300-mesh (JIS mesh, the same applies hereafter) wire mesh.

[0183] (Examples 2-6) A resin emulsion was obtained in the same manner as in Example 1, except that the types and proportions of monomers were as shown in Table 1. In Table 1, BA represents butyl acrylate and AA represents acrylic acid. Furthermore, the emulsifier SR-10 used in Example 3 is manufactured by ADEKA Corporation, and its product name is Adekaria Soap SR-10 (allyloxymethyl alkoxyethyl polyoxyethylene sulfate). Furthermore, the emulsifier NF-08 used in Example 4 is manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and its product name is Hythenol NF-08 (polyoxyethylene alkyl ether sulfate).

[0184] (Example 7) 461 parts of deionized water were placed in a flask equipped with a dropping funnel, stirrer, nitrogen inlet tube, thermometer, and reflux condenser. A dropper pre-emulsion was prepared in a dropping funnel consisting of 59 parts deionized water, 80 parts 25% aqueous solution of emulsifier (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon AR-10), and 200 parts styrene. 40 parts of this pre-emulsion was added to a flask, and the temperature was raised to 80°C while slowly blowing in nitrogen gas. Polymerization was then initiated by adding 60 parts 5% aqueous solution of potassium persulfate to the flask. Next, the remaining pre-emulsion for dropping was uniformly added to the flask dropwise over a period of 60 minutes. After the dropping was complete, the contents of the flask were maintained at 80°C for 60 minutes.

[0185] Subsequently, a second-stage pre-emulsion, consisting of 382 parts deionized water, 80 parts 25% aqueous solution of emulsifier (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon AR-10), 240 parts 2-ethylhexyl acrylate, 553 parts methyl methacrylate, 5 parts 2-hydroxyethyl methacrylate, and 2 parts silyl group-containing monomer (product name: KBM-503), was uniformly added dropwise to the flask over 60 minutes. After the addition was complete, the contents of the flask were maintained at 80°C for 60 minutes.

[0186] Finally, 25% aqueous ammonia was added to the flask to bring the pH to 8-10, and the polymerization reaction was terminated. After the resulting reaction solution was cooled to room temperature, the resin emulsion was obtained by filtering it through a 300-mesh (JIS mesh, the same applies hereafter) wire mesh.

[0187] (Example 8) 435 parts of deionized water were placed in a flask equipped with a dropping funnel, stirrer, nitrogen inlet tube, thermometer, and reflux condenser. A dropper pre-emulsion was prepared in a dropping funnel consisting of 59 parts deionized water, 80 parts 25% aqueous solution of emulsifier (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon AR-10), and 200 parts styrene. 40 parts of this pre-emulsion was added to a flask, and the temperature was raised to 80°C while slowly blowing in nitrogen gas. Polymerization was then initiated by adding 60 parts 5% aqueous solution of potassium persulfate to the flask. Next, the remaining pre-emulsion for dropping was uniformly added to the flask dropwise over a period of 60 minutes. After the dropping was complete, the contents of the flask were maintained at 80°C for 60 minutes.

[0188] Subsequently, a second-stage pre-emulsion, consisting of 166 parts deionized water, 80 parts 25% aqueous solution of emulsifier (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon AR-10), 212 parts 2-ethylhexyl acrylate, 180 parts methyl methacrylate, 5 parts 2-hydroxyethyl methacrylate, and 3 parts silyl group-containing monomer (product name: KBM-503), was uniformly added dropwise to the flask over 60 minutes. After the addition was complete, the contents of the flask were maintained at 80°C for 60 minutes.

[0189] Next, a third-stage pre-emulsion, consisting of 166 parts deionized water, 80 parts 25% aqueous solution of emulsifier (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon AR-10), 167 parts 2-ethylhexyl acrylate, 220 parts methyl methacrylate, 10 parts acrylic acid, and 3 parts silyl group-containing monomer (product name: KBM-503), was uniformly added dropwise to the flask over 60 minutes. After the addition was complete, the contents of the flask were maintained at 80°C for 60 minutes.

[0190] Finally, 25% aqueous ammonia was added to the flask to bring the pH to 8-10, and the polymerization reaction was terminated. After the resulting reaction solution was cooled to room temperature, the resin emulsion was obtained by filtering it through a 300-mesh (JIS mesh, the same applies hereafter) wire mesh.

[0191] (Example 9) A resin emulsion was obtained in the same manner as in Example 8, except that the types and proportions of monomers were as shown in Table 1.

[0192] (Example 10) A resin emulsion was obtained in the same manner as in Example 1, except that the types and proportions of monomers were as shown in Table 1.

[0193] (Comparative Example 1) A resin emulsion was obtained using the method described in Example 1 of Patent Document 1.

[0194] (Reference example 1) A resin emulsion was obtained in the same manner as in Example 1, except that Adecaria Soap SR-10 (allyloxymethyl alkoxyethyl polyoxyethylene sulfate salt), manufactured by ADEKA Corporation, was used as an emulsifier instead of Aqualon AR-10.

[0195] (Reference examples 2~3) A resin emulsion was obtained in the same manner as in Example 1, except that Adecalia Soap SR-10 was used as the emulsifier instead of Aqualon AR-10, and the types and proportions of monomers were as shown in Table 2.

[0196] (Reference example 4) A resin emulsion was obtained in the same manner as in Example 1, except that Aqualon BC-10 (sulfonate salt of propenylnonylphenyloxypolyoxyethylene), manufactured by Daiichi Kogyo Seiyaku Co., Ltd., was used as an emulsifier instead of Aqualon AR-10.

[0197] (Reference example 5) A resin emulsion was obtained in the same manner as in Example 1, except that Aqualon KH-10 (sulfonate salt of allyloxymethylalkyloxypolyoxyethylene), manufactured by Daiichi Kogyo Seiyaku Co., Ltd., was used as an emulsifier instead of Aqualon AR-10.

[0198] (Reference example 6) A resin emulsion was obtained in the same manner as in Example 1, except that instead of Aqualon AR-10 was used as an emulsifier, Hightenol NF-08 (polyoxyethylene alkyl ether sulfate), manufactured by Daiichi Kogyo Seiyaku Co., Ltd., was used.

[0199] The physical properties of the obtained resin emulsion were measured as follows. [Glass transition temperature (Tg)] The glass transition temperature is determined using the glass transition temperature of the monomer homopolymer used in the monomer components that make up the polymer. Formula (I): 1 / Tg=Σ(Wm / Tgm) / 100 (I) [In the formula, Wm represents the content (mass%) of monomer m in the monomer components constituting the polymer, and Tgm represents the glass transition temperature (absolute temperature: K) of the monomer m homopolymer.] The temperature was calculated based on Fox's formula, which is expressed as follows:

[0200] Furthermore, in cases where the emulsion has a multilayer structure, the glass transition temperature of the entire polymer constituting the multilayer emulsion was calculated from the mass fraction of each monomer in all monomer components used during multi-stage emulsion polymerization and the glass transition temperature of the corresponding monomer homopolymer.

[0201] [Solid content (NV)] The non-volatile content (solid content) of an emulsion is determined by weighing 1 g of the emulsion, drying it in a hot air dryer at 110°C for 1 hour, and considering the resulting residue as the non-volatile content. Formula: [Non-volatile content in emulsion (mass %)] = ([Mass of residue] ÷ [1g of emulsion]) × 100 It was determined based on this.

[0202] [viscosity] The viscosity at 25°C and a rotation speed of 20 rpm was determined using a BH-type viscometer (manufactured by Tokyo Keiki Co., Ltd.).

[0203] [TI] The thixotropic coefficient (TI) was defined as the viscosity at a rotational speed of 2 rpm divided by the viscosity at 20 rpm using a BH-type viscometer. TI=viscosity(2rpm) / viscosity(20rpm)

[0204] [Volume-average particle diameter] The average particle size (volume-average particle size) of the emulsion particles was measured using a dynamic light scattering particle size distribution analyzer [Particle Sizing Systems, product name: NICOMP Model 380].

[0205] [Minimum film forming temperature (MFT)] A resin emulsion was applied to a glass plate placed on a thermal gradient tester (manufactured by Tester Industries Co., Ltd.) to a thickness of 0.2 mm using an applicator. The temperature at which cracks occurred was defined as the minimum film-forming temperature.

[0206] Next, the obtained resin emulsion was evaluated by the following method.

[0207] [Method for evaluating the gloss of enamel coatings] (1) Preparation of pigment paste A pigment paste was prepared by stirring 210 parts by mass of deionized water, 60 parts by mass of dispersant [Kao Corporation, product name: Demol EP, 25% by mass aqueous solution of dispersant (solids)], 50 parts by mass of dispersant [Daiichi Kogyo Seiyaku Co., Ltd., product name: Discoat N-14, 30% by mass aqueous solution of dispersant (solids)], 10 parts by mass of humectant [Kao Corporation, product name: Emulgen LS-106, 100% by mass of humectant (solids)], 60 parts by mass of propylene glycol, 1000 parts by mass of titanium dioxide [Ishihara Sangyo Co., Ltd., product number: CR-95], and 200 parts by mass of glass beads (diameter: 1 mm) in a homodisper at a rotation speed of 3000 rpm for 60 minutes. After that, the mixture was filtered through a 60-mesh wire mesh to remove the glass beads and obtain a pigment paste.

[0208] (2) Preparation of enamel paints and viscosity response To 100 parts by mass of the above aqueous resin dispersion, 7 parts by mass of 2,2,4-trimethyl-1,3-pentanediol isobutyrate [manufactured by JNC Corporation, product number: CS-12] was added as a film-forming aid, and the mixture was stirred in a homodisperser at a rotation speed of 1500 rpm for 10 minutes. While continuing to stir, 42 parts by mass of the above pigment paste was added. The amount of pigment paste added was adjusted so that the amount of pigment was 14 volume% (40 mass%) relative to the total amount of nonvolatile matter. Furthermore, an appropriate amount of diluting water was added so that the nonvolatile matter was 50 mass%, and 0.3 mass% of a silicone-based defoaming agent [manufactured by Sunopco Corporation, product name: SN Deformer 777] relative to the total amount of paint was added to the mixture. A 5% by mass aqueous solution of a thickening agent (manufactured by ADEKA Corporation, product name: Adekanol UH-420) was added to the mixture so that the viscosity at 25°C and a rotation speed of 20 rpm was 4500 mPa·s, using a BH-type viscometer (manufactured by Tokyo Keiki Co., Ltd.). The mixture was then stirred at 1500 rpm for 30 minutes to determine the required amount of thickening agent (in grams).

[0209] [Coat strength after submersion] A clear coating was used prepared by adding 7 parts by mass of 2,2,4-trimethyl-1,3-pentanediol isobutyrate [manufactured by JNC Corporation, product code: CS-12] as a film-forming aid to 100 parts by mass of the above-mentioned aqueous resin dispersion. A clear paint was applied to a glass plate (length: 150 mm, width: 70 mm, thickness: 2 mm) using a 10-mil applicator and dried in the atmosphere at 23°C for one week to obtain a clear coating film. The obtained coating film was immersed in water adjusted to 25°C (immersed in water) and scratched with a fingernail to evaluate the coating film strength according to the following criteria. ◎: Slightly scratched but no lifting or peeling is observed. ○: Slightly scratched but lifting or peeling occurs partially. ×: Lifting or peeling occurs.

[0210] The evaluation results of the examples are shown in Table 1, and the evaluation results of the comparative examples and reference examples are shown in Table 2.

[0211]

Table 1

[0212]

Table 2

[0213] As is clear from the results in Table 1 above, according to the emulsions of Examples 1 to 9, the coating films showed excellent water resistance and the coating film strength after immersion in water was also excellent. Also, according to the emulsions of the examples, the addition amount of the thickener in the paint could be reduced.

Industrial Applicability

[0214] The present invention can provide emulsions and compositions useful as paint and the like.

Claims

1. An emulsion of a (meth)acrylic polymer comprising at least a reactive emulsifier (A) having multiple aromatic groups and a silane coupling agent (B) having polymerizable unsaturated bonding groups as polymerization components, wherein the glass transition temperature of the (meth)acrylic polymer is -40 to 80°C, the proportion of the reactive emulsifier (A) in the total emulsifier is 90% by mass or more, and the emulsion satisfies at least one selected from (1), (2), and (3) below. (1) The polymerization component does not contain radical-reactive monomers having epoxy groups. (2) The polymerization component further comprises an aliphatic (meth)acrylate (3) The emulsion has a multilayer structure.

2. An emulsion of a (meth)acrylic polymer comprising at least a reactive emulsifier (A) having multiple aromatic groups and a silane coupling agent (B) having polymerizable unsaturated bonding groups as polymerization components, wherein the glass transition temperature of the (meth)acrylic polymer is -40 to 80°C, and the proportion of the reactive emulsifier (A) in the total emulsifier is 90% by mass or more, for use in paints.

3. The emulsion according to claim 1 or 2, wherein the reactive emulsifier (A) comprises a reactive emulsifier represented by the following formula (1). 【Chemistry 1】 (In the formulas, D represents the following formula (D-1) or (D-2), A represents an alkylene group having 2 to 4 carbon atoms, and T represents a hydrogen atom or -SO ３ M (where M is a hydrogen atom, alkali metal atom, alkaline earth metal atom, or NH ４ ) indicates that l represents 1 to 2, m represents 1 to 3, and n represents 1 to 1000. 【Chemistry 2】 【Transformation 3】 (In the formula, R １ (This represents a hydrogen atom or a methyl group.)

4. The emulsion according to any one of claims 1 to 3, wherein the polymerization component further comprises one or more monomers selected from monomers having alicyclic groups and monomers having aromatic groups.

5. The emulsion according to any one of claims 1 to 4, wherein the proportion of the reactive emulsifier (A) is 0.1 to 10% by mass relative to the total polymerized components.

6. The emulsion according to any one of claims 1 to 5, wherein the proportion of the silane coupling agent (B) is 0.05 to 10% by mass relative to the total polymerized components.

7. The emulsion according to any one of claims 1 to 6, wherein the proportion of emulsifiers other than the reactive emulsifier (A) is 5% by mass or less with respect to the total polymerized components.

8. The emulsion according to any one of claims 1 to 7, wherein the polymerization component further comprises an aliphatic (meth)acrylate in a proportion of 10 to 90% by mass relative to the total polymerization component.

9. A paint composition comprising a reactive emulsifier (A) having multiple aromatic groups, a silane coupling agent (B) having polymerizable unsaturated bonding groups, and an emulsion of a (meth)acrylic polymer having at least 2-ethylhexyl (meth)acrylate as a polymerization component, and a urethane association type thickener, wherein the glass transition temperature of the (meth)acrylic polymer is -40 to 80°C.

10. The composition according to claim 9, wherein the emulsion is the emulsion described in any one of claims 1 to 8.

11. A paint comprising the emulsion according to any one of claims 1 to 8 or the composition according to any one of claims 9 to 10.

12. A coating film formed with the paint described in claim 11.

13. A building having the coating film described in claim 12.

14. A building material having the coating film described in claim 12.

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