JP7611451B1 - Resin water dispersion and its manufacturing method, as well as paint and adhesive - Google Patents

Abstract

The present invention provides an aqueous resin dispersion capable of imparting excellent water resistance to a resin film and improving the mechanical stability.
[Solution] The resin water dispersion according to the embodiment is obtained by emulsion polymerization of a monofunctional monomer (A) together with a reactive emulsifier (B) represented by formula (1), a polyfunctional monomer (C), and a silane coupling agent (D) having a polymerizable unsaturated group. In formula (1), A ¹ represents an alkanediyl group having 10 to 14 carbon atoms, A ² represents an alkanediyl group having 2 to 4 carbon atoms, n represents a number from 1 to 100, and X represents a hydrogen atom, a sulfate ester group, a phosphate ester group, a carboxymethyl group, or a salt thereof. The amount of the polyfunctional monomer (C) relative to the total amount of the reactive emulsifier (B) and the polyfunctional monomer (C) is 1 to 15% by mass. The amount of the silane coupling agent (D) relative to 100 parts by mass of the monofunctional monomer (A) is 0.01 to 0.70 parts by mass.
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Description

Embodiments of the present invention relate to a resin water dispersion, a method for producing the resin water dispersion, and a paint and adhesive containing the resin water dispersion.

Resin water dispersions, in which resins are dispersed in an aqueous dispersion medium, are used in a variety of applications, such as paints and adhesives. It is known that resin water dispersions are produced, for example, by emulsion polymerization of monomers in water. In emulsion polymerization, an emulsifier is generally used. There are reactive emulsifiers and non-reactive emulsifiers, and it is known that the use of a reactive emulsifier in emulsion polymerization tends to improve the water resistance of a resin film produced using the resin water dispersion.

For example, Patent Document 1 discloses a compound in which ethylene oxide is added to an α-olefin epoxide adduct of allyl alcohol as a reactive emulsifier that can improve the water resistance of a resin film.

On the other hand, it is known to blend a silane coupling agent into a resin aqueous dispersion obtained by emulsion polymerization. For example, Patent Document 2 describes that a (meth)acrylic emulsion that constitutes an aqueous resin composition for paint together with a water-soluble resin is obtained by emulsion polymerization using a vinyl polymerizable silane compound as a silane coupling agent together with an oxazoline group-containing monomer, a reactive group-containing monomer, and a reactive emulsifier, and that this improves the hot water whitening resistance of the coating film.

JP 2021-053585 A International Publication No. 2008/102816

Resin water dispersions used in paints, adhesives, etc. are required to produce resin films with excellent water resistance. At the same time, from the viewpoint of coatability when applying the resin water dispersion, it is considered desirable for the resin water dispersion to have excellent mechanical stability.

The object of the present invention is to provide a resin water dispersion that provides a resin film with excellent water resistance and improved mechanical stability.

The present invention includes the embodiments set forth below.
[1] A resin water dispersion obtained by emulsion polymerization of a monofunctional monomer (A) having one polymerizable unsaturated group in the molecule, together with a reactive emulsifier (B) represented by the following general formula (1), a polyfunctional monomer (C) having a plurality of polymerizable unsaturated groups in the molecule, and a silane coupling agent (D) having a polymerizable unsaturated group,
In formula (1), A ¹ represents an alkanediyl group having 10 to 14 carbon atoms, A ² represents an alkanediyl group having 2 to 4 carbon atoms, n represents the average number of moles of (A ² O) added and is a number from 1 to 100, X represents a hydrogen atom, a sulfate ester group or a salt thereof, a phosphate ester group or a salt thereof, or a carboxymethyl group or a salt thereof,
the amount of the polyfunctional monomer (C) is 1 to 15% by mass based on the total amount of the reactive emulsifier (B) and the polyfunctional monomer (C);
The amount of the silane coupling agent (D) is 0.01 to 0.70 parts by mass based on 100 parts by mass of the monofunctional monomer (A).

[2] The resin water dispersion according to [1], in which the total amount of the reactive emulsifier (B) and the polyfunctional monomer (C) is 0.3 to 7.0 parts by mass per 100 parts by mass of the monofunctional monomer (A).

[3] The resin water dispersion according to [1] or [2], wherein the polyfunctional monomer (C) includes at least one selected from the group consisting of ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,3-butylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, triallyl cyanurate, trimethallyl cyanurate, triallyl isocyanurate, trimethallyl isocyanurate, and octaallyl sucrose.

[4] The resin water dispersion according to any one of [1] to [3], wherein the silane coupling agent (D) includes at least one selected from the group consisting of a vinyl silane coupling agent, an acrylic silane coupling agent, and a methacryl silane coupling agent.

[5] A paint containing the resin water dispersion described in any one of [1] to [4].

[6] A pressure-sensitive adhesive comprising the resin water dispersion described in any one of [1] to [4].

[7] A method for producing a resin aqueous dispersion, comprising emulsion-polymerizing a monofunctional monomer (A) having one polymerizable unsaturated group in the molecule together with a reactive emulsifier (B) represented by the above general formula (1), a polyfunctional monomer (C) having a plurality of polymerizable unsaturated groups in the molecule, and a silane coupling agent (D) having a polymerizable unsaturated group in an aqueous dispersion medium, comprising:
the amount of the polyfunctional monomer (C) is 1 to 15% by mass based on the total amount of the reactive emulsifier (B) and the polyfunctional monomer (C);
The amount of the silane coupling agent (D) is 0.01 to 0.70 parts by mass relative to 100 parts by mass of the monofunctional monomer (A);
A method for producing a resin aqueous dispersion.

The resin water dispersion according to the embodiment of the present invention has excellent mechanical stability and excellent water resistance of the resin film. In addition, the resin water dispersion suppresses foaming, i.e., has excellent low foaming properties.

The resin water dispersion according to this embodiment is a resin water dispersion obtained by emulsion polymerization of a monofunctional monomer (A) together with a reactive emulsifier (B) represented by general formula (1), a polyfunctional monomer (C), and a silane coupling agent (D) having a polymerizable unsaturated group. More specifically, the resin water dispersion is a resin water dispersion in which a resin obtained by polymerizing a monofunctional monomer (A) is dispersed in an aqueous dispersion medium, and the resin contains a structure derived from the reactive emulsifier (B), a structure derived from the polyfunctional monomer (C), and a structure derived from the silane coupling agent (D) in addition to a structure derived from the monofunctional monomer (A).

[Monofunctional Monomer (A)]
The monofunctional monomer (A) is a compound having one polymerizable unsaturated group in the molecule (excluding reactive emulsifiers and silane coupling agents (D)). The monofunctional monomer (A) is a main constituent monomer of the resin as a dispersoid. The amount of the monofunctional monomer (A) in 100% by mass of all constituent monomers constituting the resin is not particularly limited, but is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.

In this specification, the term "polymerizable unsaturated group" refers to a carbon-carbon double bond that can undergo radical polymerization, and specific examples include an acryloyl group, a methacryloyl group, a vinyl group, a vinylidene group, an allyl group, and a methallyl group.

Examples of the monofunctional monomer (A) include α,β-unsaturated carboxylic acids, α,β-unsaturated carboxylic acid esters, α,β-unsaturated amides, unsaturated hydrocarbons, vinyl carboxylates, etc., and any of these may be used alone or in combination of two or more.

Examples of α,β-unsaturated carboxylic acids include (meth)acrylic acid, acrylic acid dimer, crotonic acid, itaconic acid, and maleic acid, and any one of these may be used alone or in combination of two or more.

Examples of α,β-unsaturated carboxylic acid esters include monoalkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and cyclohexyl (meth)acrylate; fluoroalkyl (meth)acrylates such as trifluoroethyl (meth)acrylate; hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-(2-hydroxyethoxy)ethyl (meth)acrylate, and hydroxypropyl (meth)acrylate; epoxy group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate and allyl glycidyl ether; amino group-containing (meth)acrylic acid esters such as dimethylaminoethyl (meth)acrylate; Examples include alkoxy group-containing (meth)acrylic acid esters such as 2-methoxyethyl (meth)acrylate and butoxyethyl (meth)acrylate; and carbonyl group-containing (meth)acrylic acid esters such as 2-(acetoacetoxy)ethyl (meth)acrylate. These may be used alone or in combination of two or more.

Examples of α,β-unsaturated amides include (meth)acrylamide, N-methylol acrylamide, and butoxy N-methylol acrylamide, and any one of these may be used alone or in combination of two or more.

Examples of unsaturated hydrocarbons include styrene-based compounds such as styrene, α-methylstyrene, vinyltoluene, dimethylstyrene, and tert-butylstyrene, and any one of these may be used alone or in combination of two or more.

Examples of vinyl carboxylates include aliphatic vinyl carboxylates such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, and vinyl cyclohexanecarboxylate; and aromatic vinyl carboxylates such as vinyl benzoate and vinyl butylbenzoate. Any of these may be used alone or in combination of two or more.

In this specification, "(meth)acrylic" means "acrylic", "methacrylic", or both, and "(meth)acrylate" means "acrylate", "methacrylate", or both.

In one embodiment, the monofunctional monomer (A) preferably contains at least one selected from the group consisting of (meth)acrylic acid esters, (meth)acrylic acid, styrene-based compounds, and vinyl carboxylates as a main component.

More preferably, the monofunctional monomer (A) contains at least one selected from the group consisting of (meth)acrylic acid esters and styrene-based compounds as a main component. Therefore, the resin as the dispersoid is preferably a (meth)acrylic resin or a styrene-based resin. Here, the (meth)acrylic resin is a resin in which the monofunctional monomer (A) contains a (meth)acrylic acid ester as a main component. The styrene-based resin is a resin in which the monofunctional monomer (A) contains a styrene-based compound as a main component.

In this specification, unless otherwise specified, "contains as a main component" means containing 50% by mass or more, more preferably containing 60% by mass or more, more preferably containing 70% by mass or more, more preferably containing 80% by mass or more, more preferably containing 90% by mass or more, and may contain 100% by mass.

[Reactive emulsifier (B)]
The reactive emulsifier (B) is a compound represented by the following general formula (1), and is an emulsifier having an allyl group, which is a polymerizable unsaturated group, in the molecule.

In formula (1), ^A1 represents an alkanediyl group having 10 to 14 carbon atoms. ^A2 represents an alkanediyl group having 2 to 4 carbon atoms. n is the average number of moles added of ( ^A2O ) and represents a number from 1 to 100. X represents a hydrogen atom, a sulfate ester group or a salt thereof, a phosphate ester group or a salt thereof, or a carboxymethyl group or a salt thereof.

As represented by formula (1), the reactive emulsifier (B) is a surfactant having an allyl group as a polymerizable site in the molecule, and having one oxyalkylene site (A ¹ O) having a long-chain alkanediyl group, and n oxyalkylene sites (A ² O) each having a short-chain alkanediyl group.

In formula (1), A ¹ is an alkanediyl group having 10 to 14 carbon atoms, but for example, as long as the carbon number is within this range, the reactive emulsifier (B) may contain multiple compounds having different carbon numbers in A ^1. When the reactive emulsifier (B) contains multiple compounds having different carbon numbers in A ¹ , the average value of the carbon numbers of A ¹ in the multiple compounds may be in the range of 10 to 14. ^{A 1} more preferably represents an alkanediyl group having 12 to 14 carbon atoms.

In formula (1), A ² is preferably an alkanediyl group having 2 to 3 carbon atoms, and more preferably an alkanediyl group having 2 carbon atoms (i.e., an ethylene group). In formula (1), A ² is an alkanediyl group having 2 to 4 carbon atoms, but as long as the carbon number is within this range, for example, the reactive emulsifier (B) may contain multiple compounds having different carbon numbers in A ^{2. When the reactive emulsifier (B) contains multiple compounds having different carbon numbers in A 2 ,} it is sufficient that the average value of the carbon numbers of A ² of the multiple compounds is in the range of 2 to 4.

In formula (1), n is preferably 2 to 80, more preferably 3 to 60, more preferably 4 to 50, and even more preferably 5 to 40.

In formula (1), X represents a hydrogen atom, a sulfate group or a salt thereof (-SO ₃ M), a phosphate group or a salt thereof (-PO _{3 M2} and/or -P(Z)O ₂ M), or a carboxymethyl group or a salt thereof (-CH ₂ -COOM). Here, M represents a hydrogen atom or a cation that forms a salt. Z represents a residue obtained by removing X from formula (1). X is preferably an anionic hydrophilic group, and more preferably a sulfate group or a salt thereof.

In the case of an anionic hydrophilic group, examples of the salt include alkali metal salts, alkaline earth metal salts, ammonium salts, and alkanolamine salts. Examples of alkali metal salts include sodium salts, potassium salts, and lithium salts. Examples of alkaline earth metal salts include calcium salts and magnesium salts. Examples of alkanolamine salts include monoethanolamine salts, diethanolamine salts, triethanolamine salts, and triisopropanolamine salts.

When X is a hydrogen atom, the compound represented by formula (1) is a nonionic emulsifier. When X is a sulfate ester group, a phosphate ester group, a carboxymethyl group, or a salt thereof, the compound represented by formula (1) is an anionic emulsifier. The reactive emulsifier (B) may be a nonionic emulsifier or an anionic emulsifier, or both may be used in combination. Preferably, the reactive emulsifier (B) contains an anionic emulsifier, and the ratio of the anionic emulsifier in 100% by mass of the reactive emulsifier (B) is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more, and may be 100% by mass.

When synthesizing the reactive emulsifier (B), a 2-mol adduct having two (A ¹ O)s may be generated together with a 1-mol adduct having one (A ¹ O) represented by formula (1). Therefore, in one embodiment, the constituent monomers of the resin as the dispersoid may contain a 2-mol adduct represented by the following formula (2) together with the reactive emulsifier (B) (1-mol adduct) represented by formula (1).
In the formula (2), A ¹ , A ² , n, and X are the same as those in the formula (1).

The amount of the 2-mol adduct of formula (2) is not particularly limited, and may be, for example, 0 to 15 parts by mass or 1 to 10 parts by mass per 100 parts by mass of reactive emulsifier (B) (1-mol adduct) of formula (1).

[Polyfunctional Monomer (C)]
The polyfunctional monomer (C) is a compound having a plurality of polymerizable unsaturated groups in the molecule (excluding reactive emulsifiers and silane coupling agents (D)). By using the polyfunctional monomer (C) in combination with the reactive emulsifier (B), the mechanical stability of the resin water dispersion can be improved, and the water resistance of the resin film can be improved.

Examples of the polyfunctional monomer (C) include (meth)allyl-based polyfunctional monomers having an allyl group (i.e., a 2-propenyl group) or a methallyl group (i.e., a 2-methyl-2-propenyl group), propenyl-based polyfunctional monomers having a 1-propenyl group, and (meth)acrylate-based polyfunctional monomers having a (meth)acryloyl group. Any one of these may be used, or two or more may be used in combination. Here, "(meth)acryloyl group" means "acryloyl group", "methacryloyl group", or both of these.

Specific examples of (meth)allyl-based polyfunctional monomers include triallyl isocyanurate, trimethallyl isocyanurate, triallyl cyanurate, trimethallyl cyanurate, diallylamine, triallyl amine, diallyl adipate, diallyl carbonate, diallyl dimethyl ammonium chloride, diallyl fumarate, diallyl isophthalate, diallyl malonate, diallyl oxalate, diallyl phthalate, diallyl propyl isocyanurate, diallyl sebacate, diallyl succinate, diallyl terephthalate, diallyl tartrate, diallyl benzene, dimethallyl benzene, 2,6-diallyl phenol, 2,6-diallyl phenol derivatives, 2,6-dimethallyl phenol, 2,6-methallyl phenol derivatives, octaallyl sucrose, etc. These may be used alone or in combination of two or more.

Specific examples of propenyl-based polyfunctional monomers include di-1-propenylbenzene, di-1-propenylphenol, and di-1-propenylphenol derivatives. These may be used alone or in combination of two or more.

Specific examples of (meth)acrylate-based polyfunctional monomers include bifunctional monomers such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, propylene glycol diacrylate, propylene glycol dimethacrylate, dipropylene glycol diacrylate, dipropylene glycol dimethacrylate, tripropylene glycol di ...acrylate, tripropylene glycol dimethacrylate, tripropylene glycol diacrylate, tripropylene glycol diacrylate, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, tripropylene glycol diacrylate, tripropylene glycol diacrylate, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, tripropylene glycol diacrylate, tripropylene glycol diacrylate, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, tripropylene glycol diacrylate, tripropylene glycol diacrylate, tripropylene glycol diacrylate, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, tripropylene glycol diacrylate, tripropylene glycol diacrylate, tripropylene glycol diacrylate Examples of the alkyl diacrylate include tripropylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, other alkylene diol diacrylates, alkylene diol dimethacrylates, etc. Other examples include diacrylates or dimethacrylates of diols derived from hydrocarbons or their alkylene oxide derivatives. Examples of trifunctional monomers include trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, tris(acryloxyethyl)isocyanurate, etc. Examples of monomers having 4 or more functional groups include pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, dipentaerythritol polyacrylate, and dipentaerythritol polymethacrylate. These may be used alone or in combination of two or more.

In the polyfunctional monomer (C), the number of polymerizable unsaturated groups contained in one molecule is preferably 2 to 8. More preferably, from the viewpoint of polymerization stability, the polyfunctional monomer (C) is a trifunctional monomer having three polymerizable unsaturated groups in the molecule. Furthermore, from the viewpoint of polymerization stability, the polyfunctional monomer (C) is preferably a (meth)acrylate-based polyfunctional monomer.

In one embodiment, as the polyfunctional monomer (C), at least one monomer (C1) selected from the group consisting of ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,3-butylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, triallyl cyanurate, trimethallyl cyanurate, triallyl isocyanurate, trimethallyl isocyanurate, and octaallyl sucrose is preferably used. In this case, the amount of the monomer (C1) in 100% by mass of the polyfunctional monomer (C) is not particularly limited, but is preferably 50% by mass or more, more preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and may be 100% by mass (i.e., only monomer (C1)).

[Silane coupling agent (D)]
Silane coupling agent (D) is a silane coupling agent having polymerizable unsaturated group.By using the silane coupling agent (D) having polymerizable unsaturated group together with the reactive emulsifier (B) and the polyfunctional monomer (C), the adhesion to inorganic substrate such as metal or glass can be improved, and the foaming of the resin water dispersion can be suppressed, and the water resistance of the resin film can be improved.

As the silane coupling agent (D), at least one coupling agent (D1) selected from the group consisting of vinyl silane coupling agents, acrylic silane coupling agents, and methacrylic silane coupling agents is preferably used. In this case, the amount of the above coupling agent (D1) in 100% by mass of the silane coupling agent (D) is not particularly limited, but is preferably 70% by mass or more, more preferably 90% by mass or more, and may be 100% by mass (i.e., only the coupling agent (D1)).

Specific examples of vinyl silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, vinyldimethoxyethoxysilane, vinyldimethoxybutoxysilane, vinyldiethoxybutoxysilane, allyltrimethoxysilane, allyltriethoxysilane, vinyltriacetoxysilane, 7-octenyltrimethoxysilane, 7-octenyltriethoxysilane, p-styryltrimethoxysilane, and the like. Any one of these may be used, or two or more may be used in combination.

Specific examples of acrylic silane coupling agents include 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, and 3-methacryloxypropylmethyldimethoxysilane. Any one of these may be used, or two or more may be used in combination.

Specific examples of methacrylsilane coupling agents include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 8-methacryloxyoctyltrimethoxysilane. Any one of these may be used alone or two or more may be used in combination.

[Aqueous dispersion medium]
The aqueous dispersion medium is a dispersion medium containing water, for example, water or a mixed medium of water and a hydrophilic organic solvent. From the viewpoint of dispersion stability of the resin water dispersion, the aqueous dispersion medium is preferably water, and an organic solvent may be contained, but it is preferable that the organic solvent is contained in a small amount. In one embodiment, the aqueous dispersion medium preferably contains 70% by mass or more of water, more preferably contains 80% by mass or more of water, more preferably contains 90% by mass or more of water, and may be 100% by mass of water.

As the hydrophilic organic solvent, various organic solvents that dissolve in water are used, for example, lower monohydric alcohols such as methanol, ethanol, and propanol, polyhydric alcohols such as ethylene glycol and glycerin, and aprotic polar solvents such as N-methylpyrrolidone, dimethyl sulfoxide, dimethylformamide, and acetonitrile.

[Resin water dispersion]
The resin water dispersion according to the embodiment is obtained by emulsion polymerization of a monofunctional monomer (A) as a main monomer together with a reactive emulsifier (B), a polyfunctional monomer (C), and a silane coupling agent (D). That is, in the method for producing the resin water dispersion according to the embodiment, the monofunctional monomer (A) is emulsion-polymerized in an aqueous dispersion medium together with the reactive emulsifier (B), the polyfunctional monomer (C), and the silane coupling agent (D).

The reactive emulsifier (B), polyfunctional monomer (C) and silane coupling agent (D) all have polymerizable unsaturated groups, and are therefore incorporated into the polymer consisting of monofunctional monomer (A) during emulsion polymerization. Therefore, the resin (i.e., polymer) obtained by emulsion polymerization contains, in addition to the structure derived from the monofunctional monomer (A), a structure derived from the reactive emulsifier (B), a structure derived from the polyfunctional monomer (C) and a structure derived from the silane coupling agent (D).

During emulsion polymerization, the amounts of monomers used to make up the polymer are set as follows:

The amount of polyfunctional monomer (C) is 1 to 15% by mass relative to the total amount of reactive emulsifier (B) and polyfunctional monomer (C). By setting the amount of polyfunctional monomer (C) used in combination with reactive emulsifier (B) in this manner, foaming of the resin water dispersion can be suppressed, mechanical stability can be improved, and the water resistance of the resulting resin film can be improved. The amount of polyfunctional monomer (C) relative to the total amount of reactive emulsifier (B) and polyfunctional monomer (C) is preferably 3 to 13% by mass, more preferably 5 to 11% by mass.

The amount of the silane coupling agent (D) is 0.01 to 0.70 parts by mass per 100 parts by mass of the monofunctional monomer (A). By setting the amount of the silane coupling agent (D) having a polymerizable unsaturated group within this range, adhesion to inorganic substrates such as metals and glass can be improved, and the water resistance of the resin film can be improved. The amount of the silane coupling agent (D) is preferably 0.05 to 0.65 parts by mass, more preferably 0.10 to 0.60 parts by mass, more preferably 0.12 to 0.50 parts by mass, and even more preferably 0.15 to 0.40 parts by mass.

In order to enhance the effect of this embodiment, it is preferable that the total amount of the reactive emulsifier (B) and the polyfunctional monomer (C) is 0.3 to 7.0 parts by mass per 100 parts by mass of the monofunctional monomer (A). The total amount of the reactive emulsifier (B) and the polyfunctional monomer (C) is more preferably 0.5 to 5.0 parts by mass, more preferably 0.8 to 4.0 parts by mass, and even more preferably 1.0 to 3.0 parts by mass.

The amount of reactive emulsifier (B) per 100 parts by mass of monofunctional monomer (A) is not particularly limited, but is preferably 0.28 to 6.8 parts by mass, more preferably 0.45 to 4.5 parts by mass, and even more preferably 0.7 to 3.8 parts by mass.

The amount of polyfunctional monomer (C) per 100 parts by mass of monofunctional monomer (A) is not particularly limited, but is preferably 0.02 to 0.35 parts by mass, more preferably 0.05 to 0.30 parts by mass, and even more preferably 0.10 to 0.25 parts by mass.

It is preferable that the monomers constituting the resin obtained by emulsion polymerization consist essentially of only the above components (A) to (D), but other monomers may be included as long as the effect is not impaired.

The emulsion polymerization method is not particularly limited, and known emulsion polymerization methods can be widely used. For example, the emulsion polymerization method includes a method in which a polymerizable compound containing a monofunctional monomer (A), a polyfunctional monomer (C), and a silane coupling agent (D) is added in the presence of an emulsifier containing a reactive emulsifier (B) in water. In this case, the polymerizable compound may be added in its entirety at once, or may be added in several portions, or may be added dropwise.

Another emulsion polymerization method is to mix a pre-emulsion in which a polymerizable compound containing a monofunctional monomer (A), a polyfunctional monomer (C) and a silane coupling agent (D) is emulsified in water with an emulsifier containing a reactive emulsifier (B) with an aqueous solution containing a polymerization initiator. When mixing the pre-emulsion with an aqueous solution containing a polymerization initiator, the entire amount of the aqueous solution may be mixed at once, or at least one of the aqueous solutions may be mixed in multiple batches, or at least one of the aqueous solutions may be added dropwise. The method for preparing the pre-emulsion is not particularly limited, and examples include a method in which an emulsifier is dissolved in water, a polymerizable compound is added thereto and the mixture is stirred. In addition, a hydrophilic organic solvent such as methanol may be used in combination in the preparation of the pre-emulsion.

In emulsion polymerization, the reaction temperature is not particularly limited and can be, for example, 50 to 100°C, and is preferably 60 to 95°C. The reaction temperature may be kept constant from the start of the reaction or may be changed during the reaction. The reaction time in emulsion polymerization is not particularly limited and can be adjusted as appropriate depending on the progress of the reaction, and is usually about 2 to 9 hours.

In emulsion polymerization, for example, a polymerization initiator, a protective colloid agent, a chain transfer agent, and a crosslinking agent may be used. There are no particular limitations on the types of these agents, and they may be agents that have been conventionally used in emulsion polymerization.

Examples of polymerization initiators include persulfates such as ammonium persulfate and potassium persulfate, peroxides such as hydrogen peroxide and benzoyl peroxide, and redox polymerization initiators that combine persulfates with reducing agents such as alkali metal sulfites and bisulfites.

In emulsion polymerization, other reactive emulsifiers may be used in combination with the reactive emulsifier (B) represented by the above formula (1) as long as the effect is not impaired. When other reactive emulsifiers are used in combination, the resin (polymer) obtained by emulsion polymerization contains a structure derived from the other reactive emulsifier. In that case, the other reactive emulsifier may be an anionic reactive emulsifier or a nonionic reactive emulsifier. In addition, as the other reactive emulsifier, for example, a two-molar adduct represented by the above formula (2) may be used. On the other hand, since the nonreactive emulsifier does not have a polymerizable unsaturated group, it is not a monomer that constitutes the resin obtained by emulsion polymerization, but is included in the resin water dispersion as a surfactant that covers the resin particles. The nonreactive emulsifier may be an anionic nonreactive emulsifier or a nonionic nonreactive emulsifier.

In the resin water dispersion, the content of the resin obtained by emulsion polymerization is not particularly limited, and may be, for example, 30 to 65% by mass, 40 to 60% by mass, or 45 to 55% by mass relative to the total mass of the resin water dispersion.

The size of the resin particles in the resin water dispersion is not particularly limited, and may be, for example, an average particle diameter of 50 to 300 nm, or 100 to 150 nm. Here, the average particle diameter is the 50% cumulative particle diameter (d50) measured using a "Microtrac UPA-UZ152" manufactured by Nikkiso Co., Ltd.

The resin aqueous dispersion may contain other components as long as the effect of the resin aqueous dispersion is not impaired. Examples of such other components include polymerization initiators, emulsifiers, protective colloids, chain transfer agents, crosslinking agents, and the like, which are agents that can be used in emulsion polymerization.

[Uses of resin aqueous dispersion]
The resin water dispersion obtained as described above has excellent mechanical stability and low foaming properties, and therefore has excellent coating properties. In addition, the resin film formed by the resin water dispersion has excellent water resistance. Moreover, by including a structure derived from the silane coupling agent (D), adhesion to inorganic substrates such as metals and glass is improved. Therefore, the resin water dispersion is suitably used in the fields of various coating materials such as paints, pressure sensitive adhesives, adhesives, binders for paper processing, and the like. Among them, the resin water dispersion is particularly suitable as a paint (e.g., water-based paint) or pressure sensitive adhesive, and has excellent coating properties and excellent water resistance of the coating film, which is the resin film, and the adhesive resin layer formed.

The paint according to the embodiment contains the resin water dispersion and may contain, together with the resin water dispersion, various additives that are generally blended into paints, such as pigments, fillers, UV absorbers, light stabilizers, surface conditioners, preservatives, rust inhibitors, antioxidants, defoamers, viscosity modifiers, antistatic agents, and association-type thickeners. In the case of paint applications, the resin as the dispersoid contained in the resin water dispersion is not particularly limited, but it is preferable that the glass transition temperature (Tg) is higher than room temperature, for example, 18°C or higher, and more preferably 20 to 120°C.

The adhesive according to the embodiment contains the resin water dispersion and may contain, together with the resin water dispersion, various additives that are generally blended into adhesives, such as tackifiers, surface conditioners, preservatives, rust inhibitors, antioxidants, defoamers, viscosity modifiers, antistatic agents, and association-type thickeners. In the case of adhesive applications, the resin as the dispersoid contained in the resin water dispersion is not particularly limited, but it is preferable that the glass transition temperature (Tg) is lower than room temperature, for example, 10°C or lower, and more preferably -50 to 5°C.

Here, the glass transition temperature Tg (°C) of the resin as the dispersoid can be calculated by the following formula using the following literature values for the glass transition temperatures Tgn (°C) of the homopolymers of each monomer:

Formula: 1/(Tg+273)=Σ[Wn/(Tgn+273)]

(In the formula, Tg (° C.) represents the glass transition temperature of the resin, Wn (-) represents the mass fraction of each monofunctional monomer (A) relative to 100% by mass of all monofunctional monomers (A), Tgn (° C.) represents the glass transition temperature of a homopolymer formed by each monofunctional monomer (A), and n represents the type of each monofunctional monomer (A).)
Styrene: 100°C
2-Ethylhexyl acrylate: -70°C
Methyl methacrylate: 105°C
Hydroxyethyl methacrylate: 55°C
Vinyl acetate: 30°C
Butyl acrylate: -55°C
Ethyl acrylate: -24°C
Methyl acrylate: 8°C
Acrylic acid: 106°C
Methacrylic acid: 185°C

The glass transition temperature of the resin can be adjusted by the composition of the monofunctional monomer (A), which is the main constituent monomer of the resin. Therefore, the composition of the monofunctional monomer (A) can be set according to the application of the paint or adhesive.

The following provides a more detailed explanation based on examples and comparative examples, but the present invention is not limited to these.

Details of the emulsifiers and silane coupling agents used in the examples are as follows:

[emulsifier]
Reactive emulsifier 1: An anionic reactive emulsifier obtained by Synthesis Example 1 below, which is a mixture of a 1-mol adduct represented by formula (1) and a 2-mol adduct represented by formula (2). In formulas (1) and (2), A ¹ is an alkanediyl group having an average carbon number of 13, A ² is an ethylene group, n is 5, and X is -SO ₃ NH _4. 1-mol adduct/2-mol adduct=95/5 (mass ratio).

(Synthesis Example 1)
In a reaction vessel equipped with a thermometer, a reflux tube, and a nitrogen inlet tube, 76 g (1.3 mol) of allyl alcohol and 8.4 g (0.15 mol) of potassium hydroxide were charged, and the temperature was raised to 80° C. under nitrogen. Then, 212 g (1.0 mol) of α-olefin epoxide (a mixture of carbon numbers 12 and 14) was added dropwise, and the reaction was carried out for 5 hours. The pressure was reduced to distill off the remaining allyl alcohol, and then the product was washed with water and dried. The resulting dried product was transferred to an autoclave, and reacted with 220 g (5 mol) of ethylene oxide in the presence of potassium hydroxide catalyst under conditions of a pressure of 1.5 kg/cm ³ and a temperature of 130° C. Then, the resulting reactant was transferred to a reaction vessel equipped with a stirrer, a thermometer, and a nitrogen inlet tube, and reacted with 97 g (1 mol) of sulfamic acid under conditions of a nitrogen atmosphere and a temperature of 120° C. Thereafter, monoethanolamine was added to adjust the pH of a 1% by mass aqueous solution to 7.5, and the solution was filtered to obtain a reactive emulsifier 1.

Reactive emulsifier 2: An anionic reactive emulsifier obtained by Synthesis Example 2 below, which is a mixture of a 1-mol adduct represented by formula (1) and a 2-mol adduct represented by formula (2). In formulas (1) and (2), A ¹ is an alkanediyl group having an average carbon number of 13, A ² is an ethylene group, n is 10, and X is -SO ₃ NH _4. 1-mol adduct/2-mol adduct=95/5 (mass ratio).

(Synthesis Example 2)
Reactive emulsifier 2 was obtained by carrying out the same operation as in the case of reactive emulsifier 1 (Synthesis Example 1), except that the amount of ethylene oxide was changed from 220 g (5 mol) to 440 g (10 mol).

Reactive emulsifier 3: An anionic reactive emulsifier obtained by Synthesis Example 3 below, which is a mixture of a 1-mol adduct represented by formula (1) and a 2-mol adduct represented by formula (2). In formulas (1) and (2), A ¹ is an alkanediyl group having an average carbon number of 13, A ² is an ethylene group, n is 20, and X is -SO ₃ NH _4. 1-mol adduct/2-mol adduct=95/5 (mass ratio).

(Synthesis Example 3)
Reactive emulsifier 3 was obtained in the same manner as in the case of reactive emulsifier 1 (Synthesis Example 1), except that the amount of ethylene oxide was changed from 220 g (5 mol) to 880 g (20 mol).

Reactive emulsifier 4: A nonionic reactive emulsifier obtained by Synthesis Example 4 below, which is a mixture of a 1-mol adduct represented by formula (1) and a 2-mol adduct represented by formula (2). In formulas (1) and (2), ^A1 is an alkanediyl group having an average carbon number of 13, ^A2 is an ethylene group, n is 20, and X is a hydrogen atom. 1-mol adduct/2-mol adduct=95/5 (mass ratio).

(Synthesis Example 4)
In a reaction vessel equipped with a thermometer, a reflux tube, and a nitrogen inlet tube, 76 g (1.3 mol) of allyl alcohol and 8.4 g (0.15 mol) of potassium hydroxide were charged, and the temperature was raised to 80°C under nitrogen. Then, 212 g (1.0 mol) of α-olefin epoxide (a mixture of carbon numbers 12 and 14) was added dropwise, and the reaction was carried out for 5 hours. The pressure was reduced to distill off the remaining allyl alcohol, and the product was washed with water and dried. The resulting dried product was transferred to an autoclave, and reacted with 880 g (20 mol) of ethylene oxide in the presence of potassium hydroxide catalyst under conditions of a pressure of 1.5 kg/cm ³ and a temperature of 130°C.

Reactive emulsifier 5: Allyloxymethylalkoxyethyl polyoxyethylene sulfate, "ADEKA REASOAP SR-10" manufactured by ADEKA Corporation

Non-reactive emulsifier 1: Polyoxyethylene alkyl ether sulfate, "Hitenol LA-12" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

Non-reactive emulsifier 2: Polyoxyalkylene alkyl ether, "Noigen XL-400D" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

[Silane coupling agent]
Silane coupling agent 1: 3-methacryloxypropyltrimethoxysilane, "KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd.

Silane coupling agent 2: 3-methacryloxypropyltriethoxysilane, "KBE-503" manufactured by Shin-Etsu Chemical Co., Ltd.

Silane coupling agent 3: Vinyltriethoxysilane, "KBM-1003" manufactured by Shin-Etsu Chemical Co., Ltd.

Silane coupling agent 4: N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, "KBM-603" manufactured by Shin-Etsu Chemical Co., Ltd.

The resin water dispersion was evaluated as follows:

[Water resistance (whitening)]
The resin water dispersion was applied to a glass plate so that the film thickness after drying would be 122 μm, and the plate was dried at 60° C. for 1 hour to obtain a resin film. The obtained film was immersed in water at 25° C., and the degree of whitening was evaluated. The glass plate on which the resin film was formed was placed on 10-point characters, and the water resistance (resistance to whitening) was evaluated according to the following criteria based on the distinguishability of the characters as viewed through the resin film.
(Judgment criteria)
A: The letters are visible even after immersion for 10 days.
B: The letters are visible after 7 days of immersion, but are not visible after 10 days of immersion.
C: The letters were visible after immersion for 3 days, but were not visible after immersion for 7 days.
D: The characters are visible after immersion for one day, but are not visible after immersion for three days.
E: After immersion for 1 day, the letters are not visible or the resin film peels off.

[Water resistance (water absorption)]
A resin water dispersion was applied to a glass plate so that the film thickness after drying would be 122 μm, and a resin film was obtained by drying for 1 hour at 60° C. The obtained resin film was immersed in water at 25° C. for 7 days, and the water absorption rate of the film was calculated using the following formula, and the water resistance (resistance to water absorption) was evaluated according to the following criteria.
Water absorption rate (mass%)={(mass of resin film after immersion−initial mass of resin film)/initial mass of resin film}×100
(Judgment criteria)
A: Water absorption rate is less than 2% by mass.
B: Water absorption rate is 2% by mass or more and less than 5% by mass.
C: Water absorption rate is 5% by mass or more and less than 8% by mass.
D: Water absorption rate is 8% by mass or more and less than 11% by mass.
E: Water absorption rate is 11 mass % or more, or the resin film peels off.

[Mechanical stability]
50 g of the resin water dispersion was weighed out and treated in a Marlon testing machine at a load of 10 kg and a rotation speed of 1000 rpm for 5 minutes, and the resulting aggregates were filtered through a 150-mesh wire screen, and the residue was washed with water and then dried at 105° C. for 2 hours. The mass was calculated as the mass % relative to the solid content of the resin water dispersion and evaluated according to the following criteria. A smaller amount of aggregates means higher stability of the resin water dispersion under high shear conditions.
(Judgment criteria)
A: The amount of aggregates is less than 3.0% by mass.
B: The amount of aggregates is 3.0% by mass or more and less than 5.0% by mass.
C: The amount of aggregates is 5.0% by mass or more and less than 7.0% by mass.
D: The amount of aggregates is 7.0% by mass or more and less than 9.0% by mass.
E: The amount of aggregates is 9.0% by mass or more.

[Low foaming]
20 mL of the resin water dispersion and 10 mL of water were placed in a 100 mL Nessler tube, and foamed by shaking by hand (30 inversions, once per second). The foam height (ml) was read after leaving it to stand for 1 minute, and the low foaming property (difficulty in foaming) was evaluated according to the following criteria.
(Judgment criteria)
A: Less than 30ml of foam.
B: Foaming is 30ml or more but less than 40ml.
C: Foaming is 40ml or more but less than 50ml.
D: Foaming is 50ml or more but less than 60ml.
E: Foam is 60ml or more.

[Adhesion]
The resin water dispersion was applied to a stainless steel (SUS) plate so that the film thickness after drying would be 10 μm, and then dried for 30 minutes at 105° C. to obtain a test piece. Using this test piece, a cross-cut test was carried out in accordance with JIS K 5400-8.5, and the adhesion was evaluated based on the rate of peeling according to the following criteria.
(Judgment criteria)
+: Peeling rate is less than 10%. -: Peeling rate is 10% or more.

[Example 1]
42 parts by mass of styrene, 33 parts by mass of 2-ethylhexyl acrylate, 23 parts by mass of methyl methacrylate, 2 parts by mass of hydroxyethyl methacrylate, 1.9 parts by mass of reactive emulsifier 1, 0.1 parts by mass of trimethylolpropane triacrylate, 0.2 parts by mass of silane coupling agent 1, and 55 parts by mass of ion-exchanged water were blended and mixed with a homomixer to prepare a mixed monomer emulsion. Separately from this, 43 parts by mass of ion-exchanged water was placed in a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen inlet tube, and a dropping funnel, and 5 parts by mass of the mixed monomer emulsion was added thereto, heated to 80 ° C., and stirred for 15 minutes. Subsequently, a mixture (aqueous solution) of 0.3 parts by mass of ammonium persulfate and 5 parts by mass of ion-exchanged water was added and mixed for 15 minutes, and the remaining mixed monomer emulsion was dropped over 3 hours. Further, after mixing for 2 hours, it was cooled and adjusted to pH 8 using ammonia water to obtain a resin water dispersion of Example 1. The glass transition temperature of the resin in the resulting resin water dispersion was 19°C.

[Examples 2 to 27 and Comparative Examples 1 to 7]
The types and amounts (parts by mass) of the emulsifier, polyfunctional monomer, and silane coupling agent were changed as shown in Tables 1 to 4 below, and the rest was the same as in Example 1 to obtain resin water dispersions of Examples 2 to 27 and Comparative Examples 1 to 7. The amounts of reactive emulsifiers 1 to 4 in Tables 1 to 4 are amounts (parts by mass) as a mixture of 1-mol adduct and 2-mol adduct.

The resin water dispersions of Examples 1 to 27 and Comparative Examples 1 to 7 were evaluated for water resistance (whitening), water resistance (water absorption), mechanical stability, low foaming, and adhesion.

In addition, in Tables 1 to 4, "(C/(B+C)) x 100" is the mass % of polyfunctional monomer (C) relative to the total amount of reactive emulsifier (B) and polyfunctional monomer (C). "((B+C)/A) x 100" is the total parts by mass of reactive emulsifier (B) and polyfunctional monomer (C) relative to 100 parts by mass of polyfunctional monomer (A). Here, the amount of reactive emulsifier (B) is the amount of 1 mole adduct of reactive emulsifiers 1 to 4. The same applies to Table 5 described later.

The results are shown in Tables 1 to 4. In Comparative Example 1, the silane coupling agent (D) was not used, and the adhesion was poor. In Comparative Example 2, the polyfunctional monomer (C) was not used, and the water resistance, low foaming property, and mechanical stability were poor. In Comparative Example 3, the amount of polyfunctional monomer (C) was too much, and the water resistance and mechanical stability were poor. In Comparative Example 4, the amount of silane coupling agent (D) was too much, and the water resistance and low foaming property were poor. In Comparative Example 5, a non-standard reactive emulsifier was used instead of the reactive emulsifier (B), and the water resistance and mechanical stability were poor. In Comparative Example 6, a non-reactive emulsifier was used instead of the reactive emulsifier (B), and the water resistance and low foaming property were poor. In Comparative Example 7, a silane coupling agent without a polymerizable unsaturated group was used instead of the silane coupling agent (D), and the adhesion was poor. In contrast, in Examples 1 to 27 according to this embodiment, the resin water dispersions obtained had excellent water resistance, mechanical stability, and low foaming properties, and also had excellent adhesion.

[Examples 28 to 31]
The type and amount (parts by mass) of the monofunctional monomer (A) were changed as shown in Table 5 below, and the other conditions were the same as in Example 1 to obtain resin water dispersions of Examples 28 to 31. In Table 5, the amount of reactive emulsifier 1 is the amount (parts by mass) of a mixture of a 1-mol adduct and a 2-mol adduct.

The glass transition temperatures of the resins in the resulting resin water dispersions were 21°C in Example 28, -0.7°C in Example 29, -26°C in Example 30, and 104°C in Example 31.

The resin water dispersions of Examples 28 to 31 were evaluated for water resistance (whitening), water resistance (water absorption), mechanical stability, low foaming properties, and adhesion.

The results are shown in Table 5. In Examples 28 to 31, in which the formulation of monofunctional monomer (A) was changed, the resin water dispersion obtained by using the specified amounts of the above-mentioned (B) to (D) components according to this embodiment was excellent in water resistance, mechanical stability, and low foaming properties, and also had excellent adhesion.

The various numerical ranges described in the specification can be arbitrarily combined with their upper and lower limits, and all such combinations are considered to be preferred numerical ranges described in this specification. In addition, a numerical range described as "X to Y" means greater than or equal to X and less than or equal to Y.

Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their omissions, substitutions, modifications, etc. are included in the scope and gist of the invention as well as the invention and its equivalents described in the claims.

Claims (6)

A resin water dispersion obtained by emulsion polymerization of a monofunctional monomer (A) having one polymerizable unsaturated group in the molecule, together with a reactive emulsifier (B) represented by the following general formula (1), a polyfunctional monomer (C) having a plurality of polymerizable unsaturated groups in the molecule, and a silane coupling agent (D) having a polymerizable unsaturated group:
In formula (1), ^A1 represents an alkanediyl group having 10 to 14 carbon atoms, ^A2 represents an alkanediyl group having 2 to 3 carbon atoms, n represents the average number of moles of ( ^A2O ) added and is a number from 1 to 100, X represents a hydrogen atom, a sulfate ester group or a salt thereof, a phosphate ester group or a salt thereof, or a carboxymethyl group or a salt thereof,
the amount of the monofunctional monomer (A) is 80% by mass or more based on 100% by mass of all constituent monomers constituting the resin as the dispersoid of the resin water dispersion,
the total amount of the reactive emulsifier (B) and the polyfunctional monomer (C) is 0.3 to 7.0 parts by mass relative to 100 parts by mass of the monofunctional monomer (A);
the amount of the polyfunctional monomer (C) is 1 to 15% by mass based on the total amount of the reactive emulsifier (B) and the polyfunctional monomer (C);
The amount of the silane coupling agent (D) is 0.01 to 0.70 parts by mass relative to 100 parts by mass of the monofunctional monomer (A);
Resin water dispersion. The resin water dispersion according to claim 1, wherein the polyfunctional monomer (C) includes at least one selected from the group consisting of ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,3-butylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, triallyl cyanurate, trimethallyl cyanurate, triallyl isocyanurate, trimethallyl isocyanurate, and octaallyl sucrose. The resin water dispersion according to claim 1, wherein the silane coupling agent (D) includes at least one selected from the group consisting of a vinyl silane coupling agent, an acrylic silane coupling agent, and a methacryl silane coupling agent. A paint comprising the resin water dispersion according to any one of claims 1 to 3 . A pressure-sensitive adhesive comprising the resin water dispersion according to any one of claims 1 to 3 . A method for producing a resin aqueous dispersion, comprising emulsion-polymerizing a monofunctional monomer (A) having one polymerizable unsaturated group in the molecule together with a reactive emulsifier (B) represented by the following general formula (1), a polyfunctional monomer (C) having a plurality of polymerizable unsaturated groups in the molecule, and a silane coupling agent (D) having a polymerizable unsaturated group in an aqueous dispersion medium,
In formula (1), ^A1 represents an alkanediyl group having 10 to 14 carbon atoms, ^A2 represents an alkanediyl group having 2 to 3 carbon atoms, n represents the average number of moles of ( ^A2O ) added and is a number from 1 to 100, X represents a hydrogen atom, a sulfate ester group or a salt thereof, a phosphate ester group or a salt thereof, or a carboxymethyl group or a salt thereof,
the amount of the monofunctional monomer (A) is 80% by mass or more based on 100% by mass of all constituent monomers constituting the resin as the dispersoid of the resin water dispersion,
the total amount of the reactive emulsifier (B) and the polyfunctional monomer (C) is 0.3 to 7.0 parts by mass relative to 100 parts by mass of the monofunctional monomer (A);
the amount of the polyfunctional monomer (C) is 1 to 15% by mass based on the total amount of the reactive emulsifier (B) and the polyfunctional monomer (C);
The amount of the silane coupling agent (D) is 0.01 to 0.70 parts by mass relative to 100 parts by mass of the monofunctional monomer (A);
A method for producing a resin aqueous dispersion.