阅读说明：本技术 树脂颗粒及其制备方法和含有该树脂颗粒的亲水性赋予剂 (Resin particle, method for producing same, and hydrophilicity-imparting agent containing same ) 是由 松本和明 于 2020-02-27 设计创作，主要内容包括：本发明提供一种可以在温和的条件下制备、对环境的负荷小的颗粒状的亲水性树脂。该树脂颗粒的特征在于,含有下述通式(1)所示的单体的至少一种与多官能乙烯性不饱和单体交联而成的交联结构,其中,R～(1)表示碳原子数1～4的烷基、氢原子、碱金属原子或季铵。(The present invention provides a granular hydrophilic resin which can be produced under mild conditions and has a small environmental load. The resin particles are characterized by containing a crosslinked structure obtained by crosslinking at least one monomer represented by the following general formula (1) with a polyfunctional ethylenically unsaturated monomer, wherein R is 1 Represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom, an alkali metal atom or a quaternary ammonium.)

1. A resin particle characterized by containing a crosslinked structure obtained by crosslinking at least one monomer represented by the following general formula (1) with a polyfunctional ethylenically unsaturated monomer,

[ chemical formula 1]

R¹Represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom, an alkali metal atom or a quaternary ammonium.

2. The resin particle according to claim 1, wherein the polyfunctional ethylenically unsaturated monomer is a non-hydrolyzable monomer.

3. The resin particle according to claim 1 or 2, wherein the polyfunctional ethylenically unsaturated monomer is a hydrocarbon-based crosslinking agent that may have an ether bond, and has 2 or more ethylenically unsaturated bonds.

4. The resin particle according to any one of claims 1 to 3, wherein the polyfunctional ethylenically unsaturated monomer is at least one of divinylbenzene and 1, 3-butadiene.

5. The resin particle according to any one of claims 1 to 4, wherein the total of monomer units derived from the general formula (1) is 30 to 99.99 mass%.

6. The resin particle according to any one of claims 1 to 5, wherein a moisture absorption rate of the resin particle is 2.5 mass% or more.

7. An aqueous dispersion comprising water and the resin particles according to any one of claims 1 to 6 dispersed in the water.

8. The aqueous dispersion according to claim 7, wherein the volume average particle diameter of the resin particles is 10nm to 10 μm.

9. A hydrophilicity-imparting agent comprising the resin particle according to any one of claims 1 to 6.

10. A method for producing a resin particle, comprising: an emulsion polymerization in which at least one of the monomers represented by the formula (2) and a polyfunctional ethylenically unsaturated monomer are dispersed in an aqueous solvent in the presence of an emulsifier to carry out a polymerization reaction,

[ chemical formula 2]

R²Represents an alkyl group having 1 to 4 carbon atoms.

Technical Field

The present invention relates to a resin particle, a method for producing the same, and a hydrophilicity-imparting agent containing the resin particle.

Background

It has been known that hydrophilicity can be imparted to a film formed from a resin composition or a coating film formed from a coating agent and the surface structure of the film or the coating film can be controlled by adding crosslinkable hydrophilic particles to the resin composition or the coating agent.

Examples of the method for producing the crosslinkable hydrophilic particles include: a method of polymerizing a hydrophilic monomer in a solvent-based solvent, and a method of hydrolyzing a polymer after polymerizing a hydrophobic monomer in an aqueous solvent. As a method for polymerizing a hydrophilic monomer in a solvent-based solvent, for example, patent document 1 discloses a method for producing hydrophilic microparticles by polymerizing acrylamide and derivatives thereof in a solvent containing a water-miscible organic solvent such as alcohol, and patent document 2 discloses hydrophilic crosslinked polymer microparticles prepared by adding a predetermined hydrophilic monomer, (meth) acrylamide-based monomer, crosslinkable unsaturated monomer, and the like to an organic solvent. Further, as a method of hydrolyzing a polymer after polymerizing a hydrophobic monomer in an aqueous solvent, for example, patent documents 3 and 4 disclose that an aqueous dispersion is obtained by polymerizing acrylonitrile and a monomer having a crosslinking property in an aqueous medium, and adding an alkali metal hydroxide such as sodium hydroxide to the obtained particles to hydrolyze the particles.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. Hei 4-132705

Patent document 2: japanese patent laid-open publication No. 8-3251

Patent document 3: japanese patent laid-open publication No. 55-27346

Patent document 4: japanese patent laid-open publication No. 2017-56404

Disclosure of Invention

Problems to be solved by the invention

However, as in patent documents 1 and 2, resin particles polymerized with a solvent-based solvent have a problem of being environmentally unfriendly in that a solvent-based solvent is used. On the other hand, when a film or a coating film is formed using a resin composition containing resin particles formed using a nitrogen atom-containing monomer as in the above-mentioned patent documents 3 and 4, there is a problem that the film or the coating film is colored. In addition, in patent documents 3 and 4, in order to obtain hydrophilic resin particles or aqueous dispersions, it is necessary to perform hydrolysis reaction using an aqueous sodium hydroxide solution (caustic soda) under severe conditions of 90 to 95 ℃.

On the other hand, when a hydrophilic monomer is polymerized in an aqueous solvent, the load on the environment is small and the severe hydrolysis conditions are not required, but the polymer is gelled in the aqueous solvent and a granular polymer cannot be obtained.

In addition, it is also conceivable to add crosslinked polyacrylic acid particles to a solvent to prepare an aqueous dispersion, but since the crosslinked polyacrylic acid particles have high hydrophilicity and the viscosity of the aqueous dispersion is also high, when used as various additives, there is a problem that the viscosity increases and mixing becomes difficult.

The present invention aims to provide a hydrophilic resin in the form of particles which does not cause an excessive increase in viscosity, can be produced under mild conditions, and has a small environmental load. It is another object of the present invention to provide a method for producing the above-mentioned particles without causing an excessive increase in viscosity even when used as various additives, and a hydrophilicity-imparting agent containing the above-mentioned particles.

Means for solving the problems

The present inventors have intensively studied to solve the above problems, and as a result, they have found that resin particles having a crosslinked structure obtained by crosslinking a specific methylolacrylic monomer as a hydrophilic monomer with a polyfunctional ethylenically unsaturated monomer can be polymerized into a granular form even when polymerized in an aqueous solvent, and do not require severe hydrolysis conditions. The resin particles thus obtained are environmentally friendly because they do not use a solvent-based solvent.

That is, the present invention includes the following inventions.

[1] A resin particle characterized by containing a crosslinked structure obtained by crosslinking at least one monomer represented by the following general formula (1) with a polyfunctional ethylenically unsaturated monomer.

[ chemical formula 1]

(R¹Represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom, an alkali metal atom or a quaternary ammonium group)

[2] The resin particle according to [1], wherein the polyfunctional ethylenically unsaturated monomer is a non-hydrolyzable monomer.

[3] The resin particle according to [1] or [2], wherein the polyfunctional ethylenically unsaturated monomer is a hydrocarbon-based crosslinking agent that may have an ether bond, and has 2 or more ethylenically unsaturated bonds.

[4] The resin particle according to any one of [1] to [3], wherein the polyfunctional ethylenically unsaturated monomer is at least one of divinylbenzene and 1, 3-butadiene.

[5] The resin particle according to any one of [1] to [4], wherein the total amount of monomer units derived from the general formula (1) is 30 to 99.99 mass%.

[6] The resin particle according to any one of [1] to [5], wherein a moisture absorption rate of the resin particle is 2.5 mass% or more.

[7] An aqueous dispersion comprising water and the resin particles according to any one of [1] to [6] dispersed in the water.

[8] The aqueous dispersion according to [7], wherein the volume average particle diameter of the resin particles is 10nm to 10 μm.

[9] A hydrophilicity-imparting agent comprising the resin particle according to any one of the above [1] to [6 ].

[10] A method for producing a resin particle, comprising: and (3) emulsion polymerization in which at least one of the monomers represented by the formula (2) and a polyfunctional ethylenically unsaturated monomer are dispersed in an aqueous solvent in the presence of an emulsifier to perform a polymerization reaction.

[ chemical formula 2]

(R²Represents an alkyl group having 1 to 4 carbon atoms. )

Effects of the invention

By copolymerizing the monomer represented by the above general formula (1) (a methylolacrylic monomer) with a crosslinkable monomer, the polymer can be granulated even when polymerized in an aqueous solvent, and hydrophilic resin particles can be produced without using a solvent. Further, by using a methylol acrylic monomer, it is possible to produce hydrophilic resin particles without hydrolysis under severe conditions.

In addition, when the resin particles of the present invention are used, the viscosity of the particle dispersion is extremely low as compared with a polyacrylic acid crosslinked product having a similar skeleton, and a blended composition can be easily obtained by adding the resin particles to various resin compositions or coating agents.

Detailed Description

1. Resin particle

The resin particles of the present invention contain a crosslinked structure obtained by crosslinking at least one monomer represented by the following general formula (1) (hereinafter referred to as a methylol acrylic monomer) with a polyfunctional ethylenically unsaturated monomer.

[ chemical formula 3]

(R¹Represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom, an alkali metal atom or a quaternary ammonium. Further, a hydrogen atom, an alkali metal atom or a quaternary ammonium may be used in the reaction of R¹Polymerizing a methylol acrylic monomer having an alkyl group of 1 to 4 carbon atoms to form resin particles, and then polymerizing R¹Introduced by hydrolysis. )

R¹The alkyl group having 1 to 4 carbon atoms is preferably an alkyl group having 1 to 2 carbon atoms, and more preferably an alkyl group (methyl group) having 1 carbon atom. The resin particles of the present invention have a monomer unit (also referred to as a structural unit) derived from a methylol acrylic monomer. Carbon double bond participates in the residue after polymerization. Hereinafter the same) may be any one of non-hydrolyzate, partial hydrolyzate, complete hydrolyzate, and hydrolysis-neutralized product. The unhydrolyzed product contains compounds derived from R¹A monomer unit of a methylol acrylic monomer having an alkyl group of 1 to 4 carbon atoms, which does not substantially contain a monomer unit derived from R¹A monomer unit of a methylolacrylic monomer which is a hydrogen atom, an alkali metal atom or a quaternary ammonium. The partial hydrolysate or the neutralized product thereof contains a residue derived from R¹A monomer unit of a methylol acrylic monomer having an alkyl group of 1 to 4 carbon atoms and a monomer unit derived from R¹Both of the monomer units of the methylol acrylic monomer which is a hydrogen atom, an alkali metal atom or a quaternary ammonium. The complete hydrolysate or the neutralized product thereof is substantially free of the product derived from R¹A monomer unit of a methylol acrylic monomer having an alkyl group of 1 to 4 carbon atoms and containing a monomer derived from R¹A monomer unit of a methylolacrylic monomer which is a hydrogen atom, an alkali metal atom or a quaternary ammonium.

The monomer unit (structural unit) derived from the methylol acrylic monomer in the resin particles is preferably 20% by mass or more, more preferably 30% by mass or more, further preferably 50% by mass or more, still more preferably 70% by mass or more, particularly preferably 80% by mass or more, most preferably 90% by mass or more, preferably 99.99% by mass or less, more preferably 99.9% by mass or less, further preferably 99% by mass or less, particularly preferably 97% by mass or less, most preferably 95% by mass or less. By setting the ratio of the monomer unit (structural unit) derived from the polyfunctional ethylenically unsaturated monomer to a predetermined amount, resin particles having high hydrophilicity can be obtained.

One or two or more species of polyfunctional ethylenically unsaturated monomers can be used, and the polyfunctional ethylenically unsaturated monomer is preferably a non-hydrolyzable monomer. As described later, the resin particles of the present invention contained in the aqueous dispersion can be hydrolyzed by adding an alkaline aqueous solution such as an aqueous sodium hydroxide solution, an aqueous ammonia solution, or an aqueous cyclohexylamine solution, and therefore the non-hydrolyzable monomer is more preferably alkali-resistant hydrolyzable. The non-hydrolyzable monomer is preferably a polyfunctional monomer (hydrocarbon) composed of only carbon atoms and hydrogen atoms, and may have an ether bond as required. In the present specification, the polyfunctional monomer which is a hydrocarbon compound having an ether bond is referred to as a hydrocarbon-based crosslinking agent having an ether bond. The hydrocarbon-based crosslinking agent which may have an ether bond preferably has 2 or more ethylenically unsaturated bonds, and more preferably has 2 ethylenically unsaturated bonds. Specifically, examples of the hydrocarbon-based crosslinking agent which may have an ether bond include: divinylbenzene; 1, 3-butadiene; trivinyl benzene; divinyl naphthalene; trivinylcyclohexane; a divinyl ether; diallyl ether; and poly (meth) acrylates. Examples of the diallyl ether include: dialkylene glycol diallyl ethers such as diethylene glycol diallyl ether, dipropylene glycol diallyl ether, and dibutylene glycol diallyl ether; polyalkylene glycol diallyl ethers such as polyethylene glycol diallyl ether, polypropylene glycol diallyl ether, and polybutylene glycol diallyl ether. Further, as the polyvalent methacrylate, there may be mentioned: ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1, 3-butanediol dimethacrylate, 1, 4-butanediol dimethacrylate, 1, 6-hexanediol dimethacrylate, 1, 9-nonanediol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol hexamethacrylate, methacrylic acid-modified polydimethylsiloxane, and the like.

The hydrocarbon-based crosslinking agent which may have an ether bond preferably has 2 or more ethylenically unsaturated bonds, and more preferably has 2 ethylenically unsaturated bonds. Specifically, examples of the hydrocarbon-based crosslinking agent which may have an ether bond include: divinylbenzene; 1, 3-butadiene; trivinyl benzene; divinyl naphthalene; trivinylcyclohexane; a divinyl ether; diallyl ether; a multi-component methacrylate; and the like, among which, at least one of divinylbenzene, 1, 3-butadiene, diallyl ether and polyvalent methacrylate is more preferable, at least one of divinylbenzene and 1, 3-butadiene is further preferable, and divinylbenzene is particularly preferable.

The proportion of the difunctional unsaturated monomer in the polyfunctional ethylenically unsaturated monomer is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 100% by mass (the polyfunctional ethylenically unsaturated monomer is composed only of the difunctional unsaturated monomer).

The monomer unit derived from the polyfunctional ethylenically unsaturated monomer in the resin particles is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, further preferably 0.5% by mass or more, particularly preferably 2% by mass or more, most preferably 5% by mass or more, preferably 70% by mass or less, more preferably 50% by mass or less, further preferably 30% by mass or less, particularly preferably 20% by mass or less, most preferably 10% by mass or less. By setting the ratio of the monomer unit derived from the polyfunctional ethylenically unsaturated monomer to a predetermined amount, resin particles having high hydrophilicity can be obtained.

The resin particles may contain monomer units derived from monomers other than the methylol acrylic monomer and the polyfunctional ethylenically unsaturated monomer, but the monomer units are preferably 75% by mass or less, more preferably 65% by mass or less, further preferably 50% by mass or less, preferably 30% by mass or less, more preferably 20% by mass or less, further preferably 10% by mass or less, particularly preferably 5% by mass or less, and most preferably 2% by mass or less.

The resin particles preferably do not contain a monomer unit derived from a monomer unit substantially containing a nitrogen atom by a covalent bond. When a film or the like is formed using a resin composition containing a nitrogen atom-containing monomer, the film or the like may be colored. Specifically, the content of nitrogen atoms in the resin particles is 1 mass% or less, preferably 0.5 mass% or less, and more preferably 0.1 mass% or less.

The resin particle of the present invention may be a core-shell particle comprising a core portion and a shell portion provided on the surface thereof. By forming the core-shell structure, the resin particles can be easily adjustedThe hydrophilicity of the surface is balanced with the hygroscopicity (water absorption) of the entire resin particle. In the case of the core-shell particles, the shell portion may have the above-mentioned structure containing a crosslinked structure in which at least one of the methylolacrylic monomers is crosslinked with the polyfunctional ethylenically unsaturated monomer. On the other hand, the core portion preferably contains a monomer unit derived from a monofunctional (meth) acrylic monomer. As the monofunctional (meth) acrylic monomer, C of (meth) acrylic acid is preferable_1-12Alkyl esters, more preferably C of (meth) acrylic acid_1-4An alkyl ester. Examples of the monofunctional (meth) acrylic monomer include: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and the like, and one or two or more of them may be used. The core portion preferably contains 50% by mass or more, more preferably 70% by mass or more, still more preferably 90% by mass or more, and particularly preferably 100% by mass of a monomer unit derived from a monofunctional (meth) acrylic monomer. The core portion may or may not contain a monomer unit derived from a methylolacrylic monomer and a polyfunctional ethylenically unsaturated monomer.

The monomer other than the monofunctional (meth) acrylic monomer may be contained, and examples of the monomer other than the monofunctional (meth) acrylic monomer include monofunctional styrene monomers. Examples of the styrene-based monomer include: alkylstyrenes such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α -methylstyrene, ethylvinylbenzene, and p-tert-butylstyrene; and styrene monofunctional monomers such as halogen group-containing styrenes such as o-chlorostyrene, m-chlorostyrene, and p-chlorostyrene. These monomers may be used alone or in combination of two or more.

The volume average particle diameter of the resin particles is preferably 10nm to 10 μm, more preferably 50nm to 5 μm, still more preferably 100nm to 1 μm, and particularly preferably 150 to 500 nm.

The resin particles preferably have a moisture absorption rate (water absorption rate) of 2.5% by mass or more, more preferably 3 to 25% by mass, and still more preferably 5 to 15% by mass at a temperature of 25 ℃ and a relative humidity of 60%. The moisture absorption rate was determined in more detail according to the procedure described in examples.

2. Polymerization process

The resin particles of the present invention are obtained by reacting R in a methylol acrylic monomer represented by the formula (1) in an aqueous solvent¹A monomer having an alkyl group having 1 to 4 carbon atoms (hereinafter referred to as a "methylolacrylate") and a polyfunctional ethylenically unsaturated monomer (hereinafter referred to as a "raw material monomer component" in some cases) and, if necessary, partially or completely hydrolyzed. When a methylolacrylate is used as the hydrophilic monomer, the product may be in the form of particles even if polymerized in an aqueous solvent. Further, since a cross-linked structure is introduced by using a polyfunctional ethylenically unsaturated monomer, even if hydrolysis is performed after polymerization, the hydrolysate can maintain a granular state. The aqueous dispersion containing water and the resin particles dispersed in the water is obtained by the above polymerization, and the aqueous dispersion will be described later.

Examples of the polymerization method include suspension polymerization, emulsion polymerization, and dispersion polymerization. Among these, emulsion polymerization in which the raw material monomer component is dispersed in a reaction solvent in the presence of an emulsifier to perform a (radical) polymerization reaction is preferable, and specifically, as a method for producing the resin particles of the present invention, a method comprising: and (3) emulsion polymerization in which at least one of the monomers represented by the formula (2) and a polyfunctional ethylenically unsaturated monomer are dispersed in an aqueous solvent in the presence of an emulsifier to perform a polymerization reaction. In addition, in the method of producing the resin particles of the present invention by the above emulsion polymerization, the amount of the monomer component used in the emulsion polymerization is adjusted to form the resin particles by the emulsion polymerization. In the case of the core-shell particles comprising a core portion and a shell portion provided on the surface thereof, the resin particles of the present invention are emulsion-polymerized so that the shell portion contains a crosslinked structure obtained by crosslinking at least one of methylolacrylic monomers and a polyfunctional ethylenically unsaturated monomer. The emulsion polymerization may be carried out in only 1 stage, or may be carried out in a plurality of stages.

[ chemical formula 4]

(R²Represents an alkyl group having 1 to 4 carbon atoms. )

The emulsifier may be one or two or more kinds, and may be a non-reactive surfactant or a reactive surfactant having a radical polymerizable group in its structure.

The non-reactive surfactant includes an anionic surfactant and a nonionic surfactant. Examples of the anionic surfactant include: fatty acid salts, alkyl (allyl) sulfonates, alkyl sulfate salts, polyoxyethylene alkyl (phenyl) ether sulfates, and the like, and examples of the nonionic surfactant include: polyoxyethylene alkyl (phenyl) ethers, polyoxyethylene sorbitol fatty acid esters, polyoxyethylene polyoxypropylene block polymers, and the like.

The reactive surfactant includes an anionic surfactant and a nonionic surfactant. Examples of the anionic reactive surfactant include, but are not limited to, an ether sulfate type reactive surfactant and a phosphate type reactive surfactant.

The ether sulfate type reactive surfactant contains a compound having a polyoxyalkylene alkyl ether sulfate or polyoxyalkylene phenyl ether sulfate as a basic skeleton and having a polymerizable alkenyl group (e.g., allyl group), a (meth) acryloyl group, or the like. Examples thereof include LATEMUL PD-104, PD-105 (manufactured by Kao corporation), ELEMINOL RS-30, NHS-20 (manufactured by Sanyo chemical Co., Ltd.), AQUALON KH-5, KH-10, KH-20 (manufactured by first Industrial pharmaceutical Co., Ltd.), ADEKA REASOAP SR-10, SR-20 and the like (manufactured by ADEKA Co., Ltd.).

The phosphate-based reactive surfactant contains a compound having an alkyl phosphate, polyoxyalkylene alkyl ether phosphate or polyoxyalkylene phenyl ether phosphate as a basic skeleton and having a polymerizable alkenyl group (e.g., allyl group), a (meth) acryloyl group, or the like. Examples thereof include SIPOMER PZ-100 (manufactured by Solvay Nighua Co., Ltd.), H-3330PL, NEW FRONTIER S-510 (manufactured by first Industrial pharmaceutical Co., Ltd.), Maximul 6106, 6112 (manufactured by Croda International PLC), and ADEKA REASOAP PP-70 (manufactured by ADEKA Co., Ltd.).

Other anionic surfactants include SIPOMER COPS1 (manufactured by Solvay Rihua Co., Ltd.), ELEMINOL JS-20 (manufactured by Sanyo chemical industries Co., Ltd.), Maximul 5010 and 5011 (manufactured by Croda International PLC).

On the other hand, the nonionic reactive surfactant contains a compound having a polyoxyalkylene alkyl ether as a basic skeleton and having a polymerizable alkenyl group (for example, allyl group), a (meth) acryloyl group, or the like. Examples thereof include ADEKAREASOAP NE-10, NE-20, NE-30, ER-10, ER-20, ER-30 (manufactured by ADEKA Co., Ltd.), LATEMUL PD-420, PD-430, PD-450 (manufactured by Kao corporation), AQUALON RN-10, RN-20, RN-30 and RN-50 (manufactured by first Industrial pharmaceutical Co., Ltd.).

The surfactant for emulsion polymerization of a methylolacrylate preferably contains a reactive surfactant, more preferably contains an anionic reactive surfactant, and further preferably contains an ether sulfate type reactive surfactant.

The emulsifier is preferably 0.05 part by mass or more, more preferably 0.1 part by mass or more, further preferably 0.3 part by mass or more, preferably 20 parts by mass or less, more preferably 10 parts by mass or less, further preferably 5 parts by mass or less, and particularly preferably 3 parts by mass or less, relative to 100 parts by mass of the total of the raw material monomer components.

Examples of the aqueous solvent include: water alone or a mixed solvent of water and a water-miscible organic solvent is preferably water alone. An aqueous solvent typically refers to a solvent having a water content of more than 50% by volume. As the water, ion-exchanged water (deionized water), distilled water, pure water, or the like can be used. As the water-miscible organic solvent, an organic solvent (lower alcohol, etc.) that can be uniformly mixed with water can be used. From the viewpoint of minimizing the organic solvent remaining in the resin particles, an aqueous solvent in which 80% by volume or more of the aqueous solvent is water is preferred, an aqueous solvent in which 90% by volume or more of the aqueous solvent is water is more preferred, an aqueous solvent in which 95% by volume or more of the aqueous solvent is water is more preferred, an aqueous solvent substantially composed of water (an aqueous solvent in which 99.5% by volume or more is water) is particularly preferred, and water alone is most preferred.

The aqueous solvent is, for example, 100 parts by mass or more, preferably 200 parts by mass or more, more preferably 400 parts by mass or more, further preferably 700 parts by mass or more, preferably 2000 parts by mass or less, more preferably 1500 parts by mass or less, and further preferably 1000 parts by mass or less, relative to 100 parts by mass of the monomer composition.

The method of adding the raw material monomer component to the reaction system is not particularly limited, and the following methods can be employed: a mode in which the whole amount is added to the reaction vessel at one time before the addition of the polymerization initiator; a mode in which after a part of the monomer composition is polymerized, the remaining part is added to the reaction system at once or in portions; a mode of continuously adding the monomer composition into the reaction system in a certain proportion; and so on. From the viewpoint of preventing the formation of a coarse polymer, a mode in which a part of the monomer composition is polymerized and then the remaining part is added (once or continuously) to the reaction system is preferable. In this case, it is preferable to add the remaining part of the monomer composition after the polymerization of a part of the monomer composition is started and before the polymerization is completed, while maintaining the polymerization temperature.

In polymerizing the raw material monomer component, for example, a polymerization initiator, irradiation with ultraviolet light or radiation, application of heat, or other means can be used, and a polymerization initiator (redox type polymerization initiator) in which an oxidizing agent and a reducing agent are combined is preferable from the viewpoint of dispersibility of the raw material monomer component.

As the oxidizing agent, one or two or more kinds may be used, and for example, there may be mentioned: hydrogen peroxide such as hydrogen peroxide, t-butyl hydroperoxide, cumene hydroperoxide, p-menthane hydroperoxide, diisopropylbenzene peroxide, 1,3, 3-tetramethylhydrogen peroxide, 2,4, 4-trimethylpentyl-2-hydroperoxide and the like; ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, and acetyl ketone peroxide; and persulfates such as potassium sulfate, ammonium persulfate, and sodium persulfate.

As the reducing agent, one or two or more kinds may be used, and for example, there may be mentioned: ascorbic acid salts such as ascorbic acid, sodium ascorbate, and potassium ascorbate; erythorbic acid, erythorbic acid sodium, erythorbic acid potassium, and other erythorbic acid salts; tartaric acid, sodium tartrate, potassium tartrate, etc.; phosphites such as phosphorous acid and sodium phosphite, potassium phosphite, and the like; hydrogen phosphites such as sodium hydrogen phosphite and potassium hydrogen phosphite; sulfites such as sodium sulfite and potassium sulfite; bisulfite salts such as sodium bisulfite and potassium bisulfite; thiosulfate salts such as sodium thiosulfate and potassium thiosulfate; thiosulfite salts such as sodium thiosulfite and potassium thiosulfite; pyrosulfite salts such as sodium pyrosulfite and potassium pyrosulfite; metabisulfites such as sodium metabisulfite and potassium metabisulfite; pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate; sodium hydroxymethanesulfonate (sodium formaldehyde sulfoxylate) and the like. In addition, according to need, sulfate or chloride salts of heavy metals such as iron, nickel, chromium, molybdenum, and cerium may be used in combination.

The redox type polymerization initiator is preferably a polymerization initiator in which at least one oxidizing agent selected from the group consisting of hydrogen peroxide and at least one reducing agent selected from the group consisting of ascorbic acid and ascorbate are combined, and more preferably a polymerization initiator in which hydrogen peroxide (oxidizing agent) and ascorbic acid (reducing agent) are combined.

The total amount of the reducing agent and the oxidizing agent is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, further preferably 1 part by mass or more, preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and further preferably 2 parts by mass or less, relative to 100 parts by mass of the total of the raw material monomer components.

The polymerization initiator may be added in its entire amount at the beginning (before the start of the reaction), or may be added in a portion at the beginning and the remainder may be added continuously, or may be added intermittently in a pulse form, or may be added by a combination of these methods.

The reaction temperature at which the polymerization reaction is carried out is, for example, preferably 30 ℃ or higher, more preferably 60 ℃ or higher, preferably 100 ℃ or lower, and more preferably 95 ℃ or lower. If the reaction temperature is within this range, the polymerization reaction can be easily controlled. The reaction time is usually preferably 10 minutes to 1200 minutes, more preferably 30 minutes to 360 minutes.

3. Aqueous dispersion

An aqueous dispersion containing the above water and the above resin particles dispersed in the water is also included in the scope of the present invention. In the aqueous dispersion of the present invention, the resin particles have ester groups and methylol groups, and are excellent in hydrophilicity. Further, the dispersion of the aqueous dispersion of the present invention is excellent in dispersibility in water and storage stability as a dispersion, and hydrolysis can be carried out more easily. In the case of hydrolysis and subsequent neutralization as needed, hydrolysis can be performed by adding an alkaline aqueous solution such as an aqueous sodium hydroxide solution, an aqueous ammonia solution, or an aqueous cyclohexylamine solution to the resin particles contained in the aqueous dispersion. Further, partial neutralization or complete neutralization can be carried out by adding an appropriate acid to the hydrolysate. By carrying out hydrolysis and neutralization, R corresponding to formula (1) can be made¹Becomes a hydrogen atom, an alkali metal atom or a quaternary ammonium. By adjusting the amounts of acid and base used in polymerization, hydrolysis and neutralization, or by adjusting R¹The ratio of the monomer unit which is a hydrogen atom can easily adjust the pH and the volume average particle diameter of the resin particles, and therefore the resin particles can be used for a wide range of applications.

The pH of the resin particles not subjected to the hydrolysis is preferably 1.5 or more and less than 7, more preferably 2 or more and 6 or less, further preferably 2.5 or more and 5.5 or less, and particularly preferably 2.7 or more and 5.0 or less. On the other hand, the pH of the resin particles subjected to the hydrolysis is preferably 5 or more and less than 14, more preferably 6 or more and 13.9 or less, further preferably 6.5 or more and 13.8 or less, and particularly preferably 7.5 or more and 13.7 or less.

The volume average particle diameter of the resin particles contained in the aqueous dispersion is preferably 10nm to 10 μm, more preferably 50nm to 5 μm, still more preferably 100nm to 1 μm, and particularly preferably 150 to 500 nm.

The present application claims the benefit of priority based on japanese patent application No. 2009-067834, filed on 29/3/2019. The entire contents of the specification of japanese patent application No. 2009-067834, filed on 29/3/2019, are incorporated herein by reference.

Examples

The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to the following examples, and can be carried out by appropriately changing the examples within the scope that can meet the gist described above and below, and all of them are included in the technical scope of the present invention.

< measurement of volume-average particle diameter of crosslinked Fine particles >

The resulting crosslinked fine Particle dispersion was diluted with ion-exchanged water and measured with a light scattering Particle size distribution analyzer ("Nicomp MODEL 380" manufactured by Particle Sizing Systems), and the volume average Particle diameter (nm) was determined and this value was defined as the volume average Particle diameter of the crosslinked fine particles.

< evaluation of hygroscopicity >

10 parts by mass of the crosslinked microparticle dispersion was weighed in a glass petri dish having an inner diameter of 4cm, and dried at 105 ℃ for 2 hours using a blast thermostat ("DNF 400" manufactured by Yamato scientific Co.). The obtained dry powder was ground with an agate mortar to obtain a dry powder. Subsequently, the dried powder was dried again at 105 ℃ for 60 minutes using a blast thermostat to obtain a powder for test.

A glass petri dish with a lid and an inner diameter of 4cm was prepared, and the mass of the petri dish was measured, and the measured mass was defined as X (g). Then, about 0.5 part by mass of the obtained test powder was put into a glass petri dish with a lid having an inner diameter of 4cm, and the lid was closed to measure the mass accurately, and the measured mass was defined as y (g). Subsequently, the plate with the test powder contained therein was placed in a constant temperature and humidity apparatus ("SH-241" manufactured by ESPEC corporation) with the cover removed, stored at a temperature of 25 ℃ and a relative humidity of 60% for 24 hours, and then the plate was taken out with the cover closed, and the mass after moisture absorption was measured, and the measured mass was defined as Z (g). The moisture absorption rate (water absorption) was calculated by the following calculation formula.

Moisture absorption rate (%) [ (Z-Y)/(Y-X) ] × 100

< preparation of coating film for evaluation (polyacrylate film) >

A coating material for evaluation was obtained by mixing a crosslinked fine particle dispersion in 5.0 parts by mass of an acrylic resin emulsion ("UW EF-015" manufactured by Nippon catalyst Co., Ltd.; polymer solid content: 50% by mass) so that the crosslinked fine particle content was 0.25 part by mass, and then sufficiently stirring the mixture with a stirring blade. The obtained coating material for evaluation was applied to a transparent polyacrylate film (manufactured by Japanese Testpanel Co., Ltd., longitudinal: 70mm, lateral: 150mm, and thickness: 2mm) with a coater so that the thickness of the coated film became 50 μm, and the film was dried at 100 ℃ for 10 minutes by using a blast thermostat ("DNF 400" manufactured by Yamato scientific Co., Ltd.) to prepare a polyacrylate film (A) in which a coating film was laminated.

< production of coating film for evaluation (polyethylene terephthalate film) >)

A coating material for evaluation was obtained by mixing a crosslinked fine particle dispersion in an amount of 0.25 part by mass to 5.0 parts by mass of an acrylic resin emulsion ("UW EF-015" manufactured by Nippon catalyst Co., Ltd., polymer solid content: 50% by mass) and sufficiently stirring the mixture with a mixer (mixer ARE-310, manufactured by thinKY CORPORATION). The obtained coating material for evaluation was applied to a transparent polyethylene terephthalate film (COSMOSHINE A4300 manufactured by Toyo Co., Ltd., longitudinal direction: 297mm, lateral direction: 210mm, thickness: 0.100mm) by a bar coater so that the thickness of the film after application was 50 μm, and dried at 100 ℃ for 10 minutes by using a blast thermostat ("DNF 400" manufactured by Yamato scientific Co., Ltd.) to prepare a polyethylene terephthalate film (B) having a coating film laminated thereon.

< production of coating film (aluminum plate) >

The coated surface of an aluminum test board (A1050P manufactured by Japan test Board, longitudinal: 150mm, lateral: 70mm, thickness: 0.800mm) was wiped with an eraser containing acetone until no black stain was present on the eraser. Next, an Ultra Sealer III (manufactured by Nippon paint Co., Ltd.) was applied to the acetone-washed aluminum test board by means of a bar coater so that the film thickness after application was 11.5. mu.m, and dried at 100 ℃ for 10 minutes by means of a blast thermostat ("DNF 400" manufactured by Yamato science Co., Ltd.) to prepare a surface-modified aluminum test board. To 5.0 parts by mass of a diluent (hereinafter referred to as "PVA (active ingredient 10.0 mass%)") obtained by diluting KURARAY POVAL 28-98 (manufactured by KURARAY corporation, degree of saponification: 98% or more, degree of polymerization: 1700) with ion-exchanged water to 10.0 mass% of an active ingredient, 5.0 parts by mass of a diluent (hereinafter referred to as "PEG (active ingredient 10.0 mass%)") obtained by diluting polyethylene glycol 3400 (manufactured by fuji film and Wako pure chemical industries, Ltd.) with ion-exchanged water to 10.0 mass% of an active ingredient was added, and the mixture was sufficiently stirred with a stirring blade to obtain a hydrophilic adhesive (active ingredient 10.0 mass%). Subsequently, a crosslinked microparticle dispersion was mixed with 10.0 parts by mass of a hydrophilic binder (active ingredient: 10.0 mass%) so that the crosslinked microparticle component became 0.20 part by mass, and then sufficiently stirred by a mixing device (mixer ARE-310, manufactured by THINKY CORPORATION) to obtain a coating material for evaluation. The obtained coating material for evaluation was applied to a surface-modified aluminum test board by a bar coater so that the film thickness after application was 11.5 μm, and dried at 200 ℃ for 1 minute by a blast thermostat ("DNF 400" manufactured by Yamato scientific corporation) to prepare an aluminum plate (C) on which a coating film was laminated.

< evaluation of hydrophilicity of coating film (polyacrylate film) >

The obtained polyacrylate film (a) on which the coating film was laminated was allowed to stand at 23 ℃ in an atmosphere having a relative humidity of 65% for one night, and then 2 μ L of pure water was dropped onto the coating film using a static contact angle measuring apparatus ("DM-500" manufactured by synechiae interface chemical corporation) to measure the contact angle after the water droplet was in contact with the surface of the coating film for 30 seconds. The contact angle of the polyacrylate film (a) without a coating film laminated thereon described as a reference example in table 1 was 84.9 °.

< evaluation of hydrophilicity of coating film (polyethylene terephthalate film, aluminum plate) >)

The contact angle was measured by the same method as described in "evaluation of hydrophilicity of coating film" (polyacrylate film) "except that the polyacrylate film (a) was replaced with the polyethylene terephthalate film (B) or the aluminum plate (C).

< determination of pH >

The value at 25 ℃ was measured using a pH meter ("F-72" manufactured by horiba Ltd.).

< example 1>

To a stainless-steel reactor equipped with a stirrer, a thermometer and a cooler, 0.96 parts by mass of a diluted solution (hereinafter referred to as "SR-20 (active ingredient 25.0 mass%)") obtained by diluting 832.0 parts by mass of deionized water and an anionic reactive surfactant adekraeasoap SR-20 (active ingredient 100 mass%, manufactured by ADEKA) containing an ether sulfate type ammonium salt as a main component with ion-exchanged water to 25.0 mass% of the active ingredient was added, and the internal temperature was raised to 75 ℃ and maintained at the temperature. On the other hand, 180.0 parts by mass of methyl 2-hydroxymethylacrylate (hereinafter referred to as "RHMA") and 20.0 parts by mass of divinylbenzene (having a divinylbenzene purity of 81%, hereinafter referred to as "DVB 810", manufactured by Nippon Tekken chemical Co., Ltd.) were mixed in a vessel different from the above-mentioned reaction vessel to prepare 200.0 parts by mass of a monomer composition. Then, the inside of the reaction vessel was replaced with nitrogen, and then 40.0 parts by mass of the monomer composition, 21.0 parts by mass of hydrogen peroxide water (hydrogen peroxide concentration: 1.28% by mass), and 21.0 parts by mass of an aqueous solution of L-ascorbic acid (L-ascorbic acid concentration: 1.90% by mass) were added to the reaction vessel to conduct initial polymerization. Subsequently, the remaining 160.0 parts by mass of the monomer composition, 479.0 parts by mass of hydrogen peroxide water (hydrogen peroxide concentration 0.22% by mass), and 486.04 parts by mass of a mixed composition of 479.0 parts by mass of an aqueous solution of L-ascorbic acid (L-ascorbic acid concentration 0.33% by mass) and 7.04 parts by mass of SR-20 (active ingredient 25.0% by mass) were uniformly dropped into the reactor over 4 hours from different inlets, respectively. After the completion of the dropwise addition, the internal temperature was raised to 85 ℃ and the reaction solution was kept at that temperature for 2 hours to age, and then the reaction solution was cooled to obtain a crosslinked microparticle dispersion (1a) in which crosslinked microparticles (1) were dispersed. Various physical properties measured using the crosslinked fine particle dispersion (1a) obtained are shown in table 1.

< example 2>

10.0 parts by mass of the crosslinked fine particle dispersion (1a) and 4.6 parts by mass of an aqueous ammonia solution (ammonia concentration: 2.8% by mass) were charged into a reaction vessel, and stirred at 25 ℃ for 30 minutes to obtain a crosslinked fine particle dispersion (2a) in which the crosslinked fine particles (2) were dispersed. The number of moles of methoxycarbonyl groups in RHMA added in the preparation of the crosslinked microparticle dispersion (1a) was the same as the number of moles of ammonia added to the crosslinked microparticle dispersion (1 a). The physical properties measured using the crosslinked fine particle dispersion (2a) thus obtained are shown in table 1.

< example 3>

1472.6 parts by mass of deionized water and 0.16 part by mass of SR-20 (active ingredient 25.0 mass%) were added to a stainless-steel reaction vessel equipped with a stirrer, a thermometer and a cooler, and the internal temperature was raised to 75 ℃ and maintained at that temperature. On the other hand, in a vessel different from the above-mentioned reaction vessel, 198.0 parts by mass of RHMA and 2.0 parts by mass of DVB810 were mixed to prepare 200.0 parts by mass of a monomer composition. Subsequently, the inside of the reaction vessel was replaced with nitrogen, and then 100.0 parts by mass of the monomer composition, 20.0 parts by mass of hydrogen peroxide water (hydrogen peroxide concentration: 2.68% by mass), and 20.0 parts by mass of an aqueous solution of L-ascorbic acid (L-ascorbic acid concentration: 4.00% by mass) were added to the reaction vessel to conduct initial polymerization. Subsequently, 168.2 parts by mass of a mixed composition of 100.0 parts by mass of the balance of the monomer composition, 160.0 parts by mass of an aqueous hydrogen peroxide solution (hydrogen peroxide concentration: 0.50% by mass), 160.0 parts by mass of an aqueous L-ascorbic acid solution (L-ascorbic acid concentration: 0.75% by mass), 7.84 parts by mass of SR-20 (active ingredient: 25.0% by mass), and 0.36 parts by mass of an aqueous ammonia solution (ammonia concentration: 28.0% by mass) were uniformly dropped into the reactor from different inlets over a period of 4 hours. After the completion of the dropwise addition, the internal temperature was raised to 85 ℃ and the reaction solution was kept at that temperature for 2 hours to age, and then the reaction solution was cooled to obtain a crosslinked microparticle dispersion (3a) in which crosslinked microparticles (3) were dispersed. Various physical properties measured using the crosslinked fine particle dispersion (3a) obtained are shown in table 1.

< example 4>

10.0 parts by mass of the crosslinked fine particle dispersion (3a) and 5.1 parts by mass of an aqueous ammonia solution (ammonia concentration: 2.8% by mass) were charged into a reaction vessel, and stirred at 25 ℃ for 30 minutes to obtain a crosslinked fine particle dispersion (4a) in which crosslinked fine particles (4) were dispersed. The number of moles of methoxycarbonyl groups in RHMA added in the preparation of the crosslinked microparticle dispersion (3a) was the same as the number of moles of ammonia added to the crosslinked microparticle dispersion (3 a). Various physical properties measured using the crosslinked fine particle dispersion (4a) obtained are shown in table 1. The crosslinked microparticles (4) are in the form of particles, but the particles contain water and swell, so that the scattering intensity is low and the accurate particle diameter cannot be measured.

< comparative example 1>

832.0 parts by mass of deionized water and 0.92 parts by mass of an aqueous solution of sodium dodecylbenzenesulfonate (active ingredient 6.5% by mass, hereinafter referred to as "DBSNa (active ingredient 6.5% by mass)") were charged into a stainless-steel reaction vessel equipped with a stirrer, a thermometer and a cooler, and the internal temperature was raised to 75 ℃ and maintained at that temperature. On the other hand, in a vessel different from the above-mentioned reaction vessel, 180.0 parts by mass of methyl methacrylate (hereinafter referred to as "MMA") and 20.0 parts by mass of DVB810 were mixed to prepare 200.0 parts by mass of a monomer composition. Then, the inside of the reaction vessel was replaced with nitrogen, and then 40.0 parts by mass of the monomer composition, 21.0 parts by mass of hydrogen peroxide water (hydrogen peroxide concentration: 1.28% by mass), and 21.0 parts by mass of an aqueous solution of L-ascorbic acid (L-ascorbic acid concentration: 1.90% by mass) were added to the reaction vessel to conduct initial polymerization. Next, the remaining 160.0 parts by mass of the monomer composition, 479.0 parts by mass of hydrogen peroxide water (hydrogen peroxide concentration 0.22% by mass), and 485.77 parts by mass of a mixed composition of 479.0 parts by mass of an aqueous L-ascorbic acid solution (L-ascorbic acid concentration 0.33% by mass) and 6.77 parts by mass of DBSNa (active ingredient 6.5% by mass) were uniformly dropped into the reactor from different inlets over 4 hours. After the completion of the dropwise addition, the internal temperature was raised to 85 ℃ and the reaction solution was kept at that temperature for 2 hours to age, and then the reaction solution was cooled to obtain a crosslinked fine particle dispersion (c1a) in which crosslinked fine particles (c1) were dispersed. Various physical properties measured using the crosslinked fine particle dispersion (c1a) thus obtained are shown in table 1.

< comparative example 2>

10.0 parts by mass of the crosslinked microparticle dispersion (c1a) and 0.5 parts by mass of an aqueous ammonia solution (ammonia concentration 28% by mass) were charged into a reaction vessel, and stirred at 25 ℃ for 30 minutes to obtain a crosslinked microparticle dispersion (c2a) in which crosslinked microparticles (c2) were dispersed. The number of moles of methoxycarbonyl groups in MMA added at the time of preparing the crosslinked fine particle dispersion (c1a) was the same as the number of moles of ammonia added to the crosslinked fine particle dispersion (c1 a). Various physical properties measured using the crosslinked fine particle dispersion (c2a) thus obtained are shown in table 1.

[ Table 1]

< examples 5-1 to 5-3>

Crosslinked fine particle dispersions (5-1a, 5-2a, 5-3a) were prepared in the same manner as in example 2, except that the amount of the aqueous ammonia solution (ammonia concentration 2.8 mass%) added was changed to the values shown in Table 2 (1.2 parts by mass (example 5-1), 2.3 parts by mass (example 5-2), and 9.2 parts by mass (example 5-3)). The pH and average particle diameter were measured using the resulting crosslinked fine particle dispersions (5-1a, 5-2a, 5-3a), and the results are shown in Table 2. The pH was also measured for the crosslinked microparticle dispersion (1a) (example 1) and the crosslinked microparticle dispersion (2a) (example 2), and the pH and the volume average particle diameter are shown in table 2, and "mol%" in table 2 shows the ratio of the amount of the aqueous ammonia solution added in each example based on the amount of the aqueous ammonia solution added in example 2 (100 mol%).

< examples 6-1 to 6-4>

Crosslinked fine particle dispersions (6-1a, 6-2a, 6-3a, 6-4a) were prepared in the same manner as in example 2 except that 1.2 parts by mass (example 6-1), 2.3 parts by mass (example 6-2), 4.6 parts by mass (example 6-3), and 9.2 parts by mass (example 6-4) of an aqueous sodium hydroxide solution (sodium hydroxide concentration: 6.6% by mass) were added instead of the aqueous ammonia solution. The pH and average particle diameter were measured using the resulting crosslinked fine particle dispersions (6-1a, 6-2a, 6-3a, 6-4a), and the results are shown in Table 2. In example 6-3, the number of moles of methoxycarbonyl groups in RHMA added at the time of preparing the crosslinked particulate dispersion (1a) was the same as the number of moles of sodium hydroxide added to the crosslinked particulate dispersion (1 a). "mol%" in table 2 shows the ratio of the amount of the sodium hydroxide aqueous solution added in each example based on the amount (100 mol%) of the sodium hydroxide aqueous solution added in 4.6 parts by mass.

< examples 7-1 to 7-3>

Crosslinked fine particle dispersions (7-1a, 7-2a, and 7-3a) were prepared in the same manner as in example 4, except that the amount of the aqueous ammonia solution (ammonia concentration 2.8 mass%) added was changed to the values shown in Table 2 (1.3 parts by mass (example 7-1), 2.5 parts by mass (example 7-2), and 10.2 parts by mass (example 7-3)). The pH and average particle diameter were measured using the resulting crosslinked fine particle dispersions (7-1a, 7-2a, and 7-3a), and the results are shown in Table 2. The pH was also measured for example 3 and example 4, and the pH is shown in table 2, and "mol%" in table 2 describes the ratio of the amount of the aqueous ammonia solution added in each example based on the amount of the aqueous ammonia solution added in example 4 (100 mol%). The crosslinked fine particles (7-1a, 7-2a, 7-3a) were in the form of granules, but the granules contained water and swelled, so that the scattering intensity was low and the accurate particle diameter could not be measured.

< examples 8-1 to 8-4>

Crosslinked fine particle dispersions (8-1a, 8-2a, 8-3a, 8-4a) were prepared in the same manner as in example 4 except that 1.3 parts by mass (example 8-1), 2.5 parts by mass (example 8-2), 5.1 parts by mass (example 8-3), and 10.2 parts by mass (example 8-4) of an aqueous sodium hydroxide solution (sodium hydroxide concentration: 6.6% by mass) were added instead of the aqueous ammonia solution. The pH was measured using the resulting crosslinked fine particle dispersions (8-1a, 8-2a, 8-3a, 8-4a), and the results are shown in Table 2. In example 8-3, the number of moles of methoxycarbonyl groups in RHMA added at the time of preparing the crosslinked particulate dispersion (3a) was the same as the number of moles of sodium hydroxide added to the crosslinked particulate dispersion (3 a). "mol%" in table 2 shows the ratio of the amount of the sodium hydroxide aqueous solution added in each example based on the amount (100 mol%) of the sodium hydroxide aqueous solution added in 5.1 parts by mass. The crosslinked fine particles (8-1a, 8-2a, 8-3a, 8-4a) were in the form of granules, but the granules contained water and swelled, so that the scattering intensity was low and the accurate particle diameter could not be measured.

[ Table 2]

< examples 9-1 to 9-2>

Crosslinked fine particle dispersions (9-1a, 9-2a) were prepared in the same manner as in example 2 except that 0.38 parts by mass (example 9-1) and 0.75 parts by mass (example 9-2) of cyclohexylamine (cyclohexylamine concentration: 100% by mass) were added instead of the aqueous ammonia solution. In example 9-2, the number of moles of methoxycarbonyl groups in RHMA added when preparing the crosslinked fine particle dispersion (1a) was the same as the number of moles of cyclohexylamine added to the crosslinked fine particle dispersion (1 a). "mol%" in table 3 shows the ratio of the addition amount of the cyclohexylamine aqueous solution in each example based on the addition amount (100 mol%) when 0.75 parts by mass of the cyclohexylamine aqueous solution is added.

< examples 10 to 14>

Crosslinked microparticle dispersions (10a to 14a) were prepared in the same manner as in example 2, except that the particle composition was changed to the particle composition shown in table 3, and an aqueous sodium hydroxide solution was added instead of the aqueous ammonia solution. The contact angles were measured using the crosslinked microparticle dispersions (10a to 14a), and the measurement results are shown in table 3. "mol%" in table 3 shows the ratio of the amount of the sodium hydroxide aqueous solution added in each example based on the amount (100 mol%) of the sodium hydroxide aqueous solution added in 4.6 parts by mass. In Table 3, "PEGDAE" is polyethylene glycol diallyl ether, and "4 EGDMA" is tetraethyleneglycol dimethacrylate, and UNIOX (registered trademark) AA-480R manufactured by Nichisu oil Co., Ltd. was used as polyethylene glycol diallyl ether, and LIGHT ESTER 4EG manufactured by Kyoeisha chemical Co., Ltd. was used as tetraethyleneglycol dimethacrylate.

< example 15>

Into a stainless steel-made 1 st reaction vessel equipped with a stirrer, a thermometer and a cooler, 1378.0 parts by mass of deionized water and 0.96 part by mass of a diluted solution (hereinafter referred to as "SR-20 (active ingredient 25 mass%)") obtained by diluting an anionic reactive emulsifier adekrasoap SR-20 (active ingredient 100 mass%, manufactured by ADEKA) containing an ether sulfate type ammonium salt as a main component with ion-exchanged water to 10 mass% of the active ingredient were added, and the internal temperature was raised to 75 ℃ and maintained at the temperature. On the other hand, 100 parts by mass of MMA was charged into a 2 nd reaction vessel different from the 1 st reaction vessel to prepare 100 parts by mass of the monomer composition A. Further, in a third reaction tank different from the first reaction tank and the second reaction tank, 90 parts by mass of RHMA and 10 parts by mass of DVB8100 were mixed to prepare 100 parts by mass of monomer composition B.

Then, the inside of the 1 st reaction vessel was replaced with nitrogen, and then 100 parts by mass of the monomer composition A, 20 parts by mass of hydrogen peroxide water (concentration: 3.35% by mass) and 20 parts by mass of an aqueous solution of L-ascorbic acid (concentration: 5.0% by mass) were added to the 1 st reaction vessel to carry out an initial polymerization reaction. Subsequently, 100 parts by mass of the monomer composition B, 100 parts by mass of hydrogen peroxide water (concentration: 0.83 mass%), and 100 parts by mass of an aqueous L-ascorbic acid solution (concentration: 1.25 mass%), and 100 parts by mass of a mixed composition (SR-20 (active ingredient: 10 mass%), 0.04 part by mass of an aqueous ammonia solution (concentration: 28 mass%), and 92.6 mass% of ion-exchanged water) were uniformly added dropwise to the first reaction vessel from different inlets over 3 hours. After completion of the dropwise addition, the internal temperature of the reaction vessel 1 was maintained at 75 ℃ for 2 hours to age the reaction mixture, and then the reaction mixture was cooled to obtain an aqueous polymer dispersion (15) in which a polymer (15) was dispersed.

10 parts by mass of the obtained aqueous polymer dispersion (15) and 0.76 part by mass of an aqueous sodium hydroxide solution (concentration 10.0% by mass) as an alkaline aqueous solution were added to the first reaction tank, and stirred overnight at 25 ℃ to thereby obtain an aqueous polymer dispersion (15) in which a partially hydrolyzed polymer was dispersed.

< example 16, example 17>

Crosslinked microparticle dispersions (16 to 17) were prepared in the same manner as in example 15, except that the particle composition was changed to the particle composition shown in table 3, and "BA" in table 3 was n-butyl acrylate.

< comparative example 3>

A crosslinked microparticle dispersion (c3a) was prepared in the same manner as in example 1, except that the particle composition was changed to the particle composition shown in table 3. The contact angle was measured using the crosslinked microparticle dispersion (c3a), and the measurement results are shown in table 3.

< comparative example 4>

A10-liter glass reactor equipped with a stirrer, a dropping device and a thermometer was charged with 4266.5g of methanol as an organic solvent and 333.0g of 28 wt% aqueous ammonia (water and catalyst) and the liquid temperature was adjusted to 20. + -. 0.5 ℃ while stirring. On the other hand, a solution of 333.0g of tetramethoxysilane (silicon compound) dissolved in 533.0g of methanol was charged into a dropping device. Then, the solution was dropwise added from the dropping device over 1 hour. After completion of the dropwise addition, the mixture was further stirred for 1 hour to hydrolyze and condense tetramethoxysilane, thereby obtaining a suspension of silica particles. The silica particles had an average particle diameter of 100 nm. The resulting suspension was dried using an instantaneous vacuum evaporator, and thereby silica particles in a powder form were taken out. As an instantaneous vacuum drying apparatus, Clax System 8B model (manufactured by Hosokawa Micron Co., Ltd.) was used. Further, as the drying conditions, a heating pipe temperature of 175 ℃ and a reduced pressure of 200torr were used. The above-mentioned instantaneous vacuum evaporation device is provided with: a stainless steel tube having an inner diameter of 8mm and a length of 9m, which is covered with a jacket for supplying heating steam; a supply unit that supplies the suspension to one end of the steel pipe; and a powder collecting chamber in a reduced pressure state connected to the other end of the steel pipe and provided with a bag filter for separating the powder from the vapor. The suspension supplied from the supply unit is heated and separated into powder and steam while passing through the steel pipe, the powder is collected by the bag filter, and the steam is condensed and discharged to the outside of the apparatus.

A crosslinked fine particle dispersion (c4a) was prepared in the same manner as in example 1, except that the above silica particles in powder form were used as the particles. The contact angle was measured using the resulting crosslinked fine particle dispersion (c4a), and the measurement results are shown in table 3.

< comparative example 5>

1400 parts of deionized water and 6 parts of 65 wt% DBSDA were charged into a stainless-steel reactor equipped with a stirrer, a thermometer and a cooler, and the internal temperature was raised to 90 ℃ and maintained at that temperature.

On the other hand, 100 parts of melamine, 193 parts of 37 wt% formaldehyde and 3 parts of 25 wt% aqueous ammonia were charged into a reaction vessel having the same equipment as described above, which was different from the above-mentioned reaction vessel, and the temperature was raised to 70 ℃ and the vessel was kept at the same temperature for 40 minutes, and then the vessel was charged into the 65 wt% aqueous DBSNa solution kept at 90 ℃. Then, 50 parts of a10 wt% aqueous DBS solution was added and kept at 90 ℃ for 5 hours for aging to obtain a dispersion containing amino resin particles. To 1752 parts of the dispersion containing the amino resin particles, 30 parts of a10 wt% aluminum sulfate aqueous solution was added and stirred for 30 minutes. Then, the dispersion was subjected to solid-liquid separation by a centrifugal separator, and the obtained cake was dried in a hot air dryer maintained at 190 ℃ for 5 hours under a nitrogen atmosphere, and after drying, pulverized and air-classified by a jet pulverizer (pulverization pressure: 0.7MPa) to obtain melamine resin particles. The melamine particles had an average particle size of 200 nm.

A crosslinked microparticle dispersion (c5a) was prepared in the same manner as in example 1, except that the melamine particles were used as the particles. The contact angle was measured using the resulting crosslinked fine particle dispersion (c5a), and the measurement results are shown in table 3.

< comparative example 6>

A crosslinked microparticle dispersion (c6a) was prepared in the same manner as in example 1, except that crosslinked polyacrylic acid (100 CLPAH manufactured by fuji photo film co., ltd.) was used as the particles. However, in comparative example 6 using the crosslinked polyacrylic acid, the viscosity was too high to be blended.

< viscosity of aqueous Dispersion >

The crosslinked microparticle dispersion (6-3a) was dried with a spray dryer (GA-32 manufactured by Yamato scientific Co., Ltd.) to obtain a crosslinked microparticle powder (6-3 b). 9.0 parts by mass of ion-exchanged water was added to 1.0 part by mass of the crosslinked fine particle powder (6-3b), and the resulting mixture was thoroughly stirred with a stirring blade to prepare a 10% by mass aqueous dispersion. Then, 1 part by mass of the aqueous dispersion was added to a sample dish using a cone plate type viscometer (DV-II + Pro, Brookfield, spindle No. CPE-42, rotation speed 30rpm), and the viscosity of the aqueous particle dispersion at 25 ℃ was measured to be 5.62 mPas.

The viscosity of the 0.1 mass% aqueous dispersion of the crosslinked polyacrylic acid particles used in comparative example 6 was measured in the same manner, and as a result, the viscosity was 10.4mPa · s, and the viscosity was extremely high even though only 0.1 mass% of the crosslinked polyacrylic acid particles was contained.

Therefore, it can be said that the resin particles of the present invention have extremely high compatibility when used as various additives.

[ Table 3]

INDUSTRIAL APPLICABILITY

The resin particles of the present invention can be used as a hydrophilicity-imparting agent, a moisture-absorbing agent, a column filler, an antistatic agent, or as a stain-resistant coating material, a water-absorbing resin, a matting agent, a medical diagnostic agent, a coating agent, a water-retaining agent, a moisture-absorbing releasing agent, a refractive index adjusting agent, an anti-blocking agent, an antifogging agent, or the like.