JP2022053193A - Resin composition for paint - Google Patents

Abstract

[Problem] The objective of the present invention is to provide an aqueous resin composition for paints, which has good blend stability and gives a coating film with good water-whitening resistance and stain resistance. [Solution] The aqueous resin composition for paints contains polymer particles, the polymer particles containing a structural unit represented by the following general formula (1) and a structural unit derived from a polyfunctional ethylenically unsaturated monomer. TIFF2022053193000009.tif2449 (In general formula (1), R1 represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom, an alkali metal atom, or ammonium.) [Selected Figure] None

Description

The present invention relates to a resin composition for paints. More specifically, the present invention relates to an aqueous resin composition for paints, which has excellent compounding stability.

For example, when a building is exposed to the outdoors for a long period of time, the painted surface becomes dirty or the appearance deteriorates due to the influence of rain, dust, sunlight and the like. Therefore, there is a market need for a so-called low-contamination paint that improves stain resistance. As a means for this, a method of blending silica sol with a paint is known (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-177604

As described above, a low-contamination paint composition containing fine particle silica has been proposed, but when silica particles having a large particle size are contained, there are problems that the coating film becomes cloudy and the water whitening resistance deteriorates. there were. On the other hand, when silica particles having a small particle size are contained, the composition may be gelled and the compounding stability may not be sufficient, and there is a problem that a good coating film cannot be obtained.

Therefore, an object of the present invention is to provide an aqueous resin composition for paints, which has good compounding stability and good water whitening resistance and antifouling property of the obtained coating film.

The present inventor has made various studies in order to achieve the above object, and came up with the present invention.
That is, the resin composition for coating material of the present disclosure contains polymer particles, and the polymer particles have a structural unit represented by the following general formula (1) and a structure derived from a polyfunctional ethylenically unsaturated monomer. A water-based resin composition for paints, which comprises a unit.

(In the general formula (1), R ¹ represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom, an alkali metal atom, or ammonium.)

The aqueous resin composition for paints of the present disclosure has good compounding stability, and a coating film having good water whitening resistance and antifouling property can be obtained. Therefore, the aqueous resin composition for paints of the present disclosure can be suitably used for, for example, paints for building materials.

Hereinafter, the present invention will be described in detail.
It should be noted that a combination of two or more of the individual preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

[Polymer particles of the present disclosure]
The structural unit of the present disclosure includes a structural unit represented by the general formula (1) described later and a structural unit derived from a polyfunctional ethylenically unsaturated monomer, and may be added to other monomers as necessary. It has a structural unit of origin.

<Structural unit represented by the general formula (1)>
The polymer particles of the present disclosure include a structural unit represented by the following general formula (1).

(In the general formula (1), R ¹ represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom, an alkali metal atom, or ammonium.)
The alkyl group having 1 to 4 carbon atoms represented by R ¹ is preferably an alkyl group having 1 to 2 carbon atoms, and more preferably an alkyl group having 1 carbon atom (methyl group).

The structural unit represented by the general formula (1) may be formed by the monomer represented by the following general formula (2) passing through a polymerization reaction, or may be formed by another method. good. For example, in the general formula (2), R ¹ is an alkali metal structure in the above general formula ( ¹ ) by polymerizing and hydrolyzing a monomer having an alkyl group having 1 to 4 carbon atoms. Units and structural units of ammonium may be formed.

(In the general formula (2), R ¹ represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom, an alkali metal atom, or ammonium.)
In the above general formula (1), R ¹ may be one kind or two or more kinds. When R ¹ is two or more kinds, it may be formed by polymerizing two or more kinds of monomers represented by the above general formula (2), and R ¹ is an alkyl group having 1 to 4 carbon atoms. After polymerizing the monomer represented by the general formula (2), the ester group may be partially hydrolyzed or formed by hydrolysis with two or more basic substances.

The above R ¹ is defined to mean that ammonium is not limited to NH ⁴⁺ but includes organic ammonium. Examples of the organic ammonium include quaternary ammonium such as tetraalkylammonium such as tetramethylammonium and tetrabutylammonium; and ammonium (1st to tertiary ammonium) formed by protonating an amine. As ^R1 , ammonium formed by protonation of ammonia or amine is preferable. Examples of the amine include trialkylamines such as trimethylamine, triethylamine and tributylamine (preferably tri-C _1-10 alkylamines); hydroxyalkylamines such as diethanolamine and triethanolamine (preferably di or tri (hydroxy C _1-10 )). Alkyl) amines and the like) are mentioned, and hydroxyalkylamines are preferable.

The polymer particles of the present disclosure preferably contain the structural unit represented by the general formula (1) in an amount of 20% by mass or more, more preferably 30% by mass or more, and further preferably 50% by mass or more. , 70% by mass or more is more preferable, 80% by mass or more is particularly preferable, and 90% by mass or more is most preferable. On the other hand, the polymer particles of the present disclosure preferably contain the structural unit represented by the general formula (1) in an amount of 99.99% by mass or less, more preferably 99.9% by mass or less, and 99% by mass. It is more preferably contained below, particularly preferably 97% by mass or less, and most preferably 95% by mass or less. By including it in the above range, the compounding stability, water whitening resistance, and stain resistance of the aqueous resin composition for paints of the present disclosure tend to be improved.

The polymer particles of the present disclosure may have a multilayer structure, and may be, for example, core-shell particles composed of a core portion and a shell portion provided on the surface thereof. When the polymer particles of the present disclosure have a multilayer structure, the composition of the outermost shell layer is preferably in the above range.

<Structural unit derived from polyfunctional ethylenically unsaturated monomer>
In the present disclosure, the structural unit derived from the polyfunctional ethylenically unsaturated monomer is a structural unit in which at least one carbon-carbon double bond of the polyfunctional ethylenically unsaturated monomer is replaced with a carbon-carbon single bond. Represents. For example, if divinylbenzene, CH ₂ = CH-C ₆ H ₄ -CH = CH ₂ , then the structural unit derived from divinylbenzene is, for example, -CH ₂ -CH-C ₆ H ₄ -CH-CH _2- , Can be represented by. The structural unit derived from the polyfunctional ethylenically unsaturated monomer can be formed, for example, by radical polymerization of the polyfunctional ethylenically unsaturated monomer. The structural unit derived from the polyfunctional ethylenically unsaturated monomer may have the same structure as the structure in which the carbon-carbon double bond of the polyfunctional ethylenically unsaturated monomer is replaced with the carbon-carbon single bond. The structural unit is not limited to the structural unit formed by the polymerization of the functional ethylenically unsaturated monomer, and may be, for example, the structural unit formed by the post-reaction after the polymerization.
The polymer particles of the present disclosure may contain one or more structural units derived from the polyfunctional ethylenically unsaturated monomer.

In the present disclosure, the polyfunctional ethylenically unsaturated monomer is not particularly limited as long as it is a compound containing 2 or 3 or more ethylenic carbon-carbon double bonds, but is not particularly limited, for example, CH ₂ = CH-group, CH. ₂ = CH-O- group, CH ₂ = CH-CH ₂ -O- group, CH ₂ = C (CH ₃ ) -CH ₂ -O- group, CH ₂ = CH-CH ₂ -CH ₂ -O- group , CH ₂ = C (CH ₃ ) -CH ₂ -CH ₂ -O- group, CH ₂ = CH-CO-O- group, CH ₂ = C (CH ₃ ) -CO-O- group, CH ₂ = CH Examples are compounds containing 2 or 3 or more ethylenically carbon-carbon double bonds of one or more selected from the -CO-NH- group.

In the present disclosure, the polyfunctional ethylenically unsaturated monomer preferably has a molecular weight of 50 or more and 1000 or less, and more preferably 100 or more and 400 or less.

The polyfunctional ethylenically unsaturated monomer includes divinylbenzene; 1,3-butadiene; trivinylbenzene; divinylnaphthalene; trivinylcyclohexane; divinyl ether; diallyl ether; polyvalent methacrylic acid ester, N, N. '-Methylenebisacrylamide and the like are exemplified. From the viewpoint of hydrolysis resistance, divinylbenzene, diallyl ether, polyvalent methacrylic acid ester and the like are preferable, divinylbenzene and polyvalent methacrylic acid ester are more preferable, and divinylbenzene is still more preferable.

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; and polyalkylene glycols such as polyethylene glycol diallyl ether, polypropylene glycol diallyl ether and polybutylene glycol diallyl ether. Dialyl ether can be mentioned. Examples of the polyvalent methacrylic acid ester include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, and 1,4-butane. Didioldimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, trimethylolpropanetrimethacrylate, pentaerythritol trimethacrylate, Examples thereof include pentaerythritol tetramethacrylate, dipentaerythritol hexamethacrylate, and methacrylic-modified polydimethylsiloxane.

The polymer particles of the present disclosure preferably contain 0.01% by mass or more, more preferably 0.1% by mass or more, of structural units derived from the polyfunctional ethylenically unsaturated monomer. It is more preferably contained in an amount of 5% by mass or more, further preferably contained in an amount of 2% by mass or more, and particularly preferably contained in an amount of 5% by mass or more. On the other hand, the polymer particles of the present disclosure preferably contain 70% by mass or less, more preferably 50% by mass or less, and 30% by mass or less of the structural unit derived from the polyfunctional ethylenically unsaturated monomer. It is more preferably contained, more preferably 20% by mass or less, and most preferably 10% by mass or less. By including it in the above range, the compounding stability, water whitening resistance, and stain resistance of the aqueous resin composition for paints of the present disclosure tend to be improved.

The ratio of the structural unit derived from the bifunctional unsaturated monomer to 100% by mass of the structural unit derived from the polyfunctional ethylenically unsaturated monomer contained in the polymer particles of the present disclosure is 50% by mass or more. It is preferably 70% by mass or more, more preferably 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 100% by mass.

When the polymer particles of the present disclosure have a multilayer structure, the composition of the outermost shell layer is preferably in the above range.

<Structural unit derived from other monomers>
The polymer particles of the present disclosure are structural units derived from a monomer other than the structural unit represented by the above general formula (1) and the structural unit derived from the polyfunctional ethylenically unsaturated monomer (hereinafter, “others”). It may contain one kind or two or more kinds (also referred to as "structural unit derived from the monomer of the above"). That is, a structural unit derived from a monomer represented by the above general formula (2) or a monomer other than the polyfunctional ethylenically unsaturated monomer (hereinafter, also referred to as “other monomer”). It may contain one kind or two or more kinds.

Other monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2- (Meta) acrylic monomers such as ethylhexyl (meth) acrylate and lauryl (meth) acrylate; styrene monomers such as styrene, α-methylstyrene, p-methylstyrene, tert-butylstyrene, chlorostyrene, vinyltoluene; Monomer containing carboxyl groups such as (meth) acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, maleic anhydride; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (methoxyethoxy) silane, γ-( Meta) Amount containing silane groups such as acryloyloxypropyltrimethoxysilane, 2-styrylethyltrimethoxysilane, vinyltrichlorosilane, γ- (meth) acryloyloxypropylhydroxysilane, and γ- (meth) acryloyloxypropylmethylhydroxysilane Body: Containing hydroxyl groups such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc. Monomer; Nitrogen atom-containing monomer such as (meth) acrylamide, N, N-dimethyl (meth) acrylamide, dimethylaminoethyl (meth) acrylamide, N-vinylpyrrolidone, (meth) acrylonitrile; ethylene glycol methoxy (meth) ) Oxo group-containing monomers such as acrylates and diethylene glycol methoxy (meth) acrylates; Fluorine atom-containing monomers such as trifluoroethyl (meth) acrylates, tetrafluoropropyl (meth) acrylates and octafluoropentyl (meth) acrylates; Epoxy group-containing monomer such as glycidyl (meth) acrylate; light-stabilizing monomer such as 2,2,6,6-tetramethylpiperidine-4- (meth) acrylate; benzotriazole-based ultraviolet-absorbing monomer , UV-absorbing monomers such as benzophenone-based UV-absorbing monomers are exemplified.

The content of the structural unit derived from other monomers in the polymer particles of the present disclosure is preferably 75% by mass or less, more preferably 65% by mass or less, and more preferably 50% by mass or less. It is more 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 2% by mass. % Or less is most preferable.

Within the above range, the formulation stability, water whitening resistance, and stain resistance of the aqueous resin composition for paints of the present disclosure tend to be improved.

The polymer particles of the present disclosure may have a multilayer structure, and may be, for example, core-shell particles composed of a core portion and a shell portion provided on the surface thereof. When the polymer particles of the present disclosure have a multilayer structure, the composition of the outermost shell layer is preferably in the above range.

As described above, when the polymer particles of the present disclosure have a multilayer structure, the outermost layer is derived from the structural unit represented by the general formula (1) and the polyfunctional ethylenically unsaturated monomer. It is preferable to include the structural unit to be used indispensably.
On the other hand, at least one layer other than the outermost shell may contain at least one selected from a structural unit derived from a (meth) acrylic monomer and a structural unit derived from a styrene-based monomer. preferable. It is preferable that the structural units derived from the (meth) acrylic monomer and / or the structural units derived from the styrene-based monomer are contained in an amount of 50% by mass or more in total, and more preferably 70% by mass or more. It is more preferably contained in an amount of 90% by mass or more, and particularly preferably contained in an amount of 100% by mass.

<Characteristics of polymer particles of the present disclosure>
The polymer particles of the present disclosure preferably have a volume average particle diameter of 10 nm to 10 μm, more preferably 50 nm to 5 μm, further preferably 100 nm to 1 μm, and particularly preferably 150 to 500 nm. preferable.

The polymer particles of the present disclosure preferably have a glass transition temperature of 80 ° C. or higher, more preferably 100 ° C. or higher, and even more preferably 150 ° C. or higher.

[Method for producing polymer particles of the present disclosure]
The polymer particles of the present disclosure are not particularly limited, but among the hydroxymethylacrylic acid-based monomers represented by the formula (2), those in which R ¹ is an alkyl group having 1 to 4 carbon atoms (hereinafter, hydroxymethyl). Acrylic acid ester) and polyfunctional ethylenically unsaturated monomer (hereinafter, these may be collectively referred to as "raw material monomer component") are polymerized in an aqueous solvent, and if necessary, partially. It is preferably produced by hydrolysis or by complete hydrolysis.
Examples of the polymerization method include suspension polymerization, emulsion polymerization, dispersion polymerization and the like. Among them, emulsion polymerization in which the above-mentioned raw material monomer component is dispersed in a reaction solvent and a (radical) polymerization reaction is carried out in the presence of an emulsifier is preferable. Specifically, as a method for producing polymer particles of the present invention, an emulsifier is used. In the presence of, it is preferable to include emulsion polymerization in which at least one of the monomers represented by the formula (2) and the polyfunctional ethylenically unsaturated monomer are dispersed in an aqueous solvent to carry out a polymerization reaction. The emulsion polymerization may be carried out in only one step or in multiple steps.

As the emulsifier, one kind or two or more kinds can be used, and it may be a non-reactive surfactant or a reactive surfactant having a radically polymerizable group in its structure.

Non-reactive surfactants include anionic and nonionic surfactants. Examples of the anionic surfactant include fatty acid salts, alkyl (allyl) sulfonates, alkyl sulfate esters, polyoxyethylene alkyl (phenyl) ether sulfates and the like, and examples of the nonionic surfactant include polyoxyethylene. Examples thereof include alkyl (phenyl) ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty acid ester, and polyoxyethylene polyoxypropylene block polymer.

Reactive surfactants include anionic and nonionic surfactants. Examples of the anionic reactive surfactant include, but are not limited to, an ether sulfate type reactive surfactant and a phosphoric acid ester type reactive surfactant.

The emulsifier is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and further preferably 0.3 parts by mass or more with respect to 100 parts by mass of the total of the raw material monomer components. , 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.

In the present disclosure, the aqueous solvent includes water alone or a mixed solvent of water and a water-miscible organic solvent, but water alone is preferable. The 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 and the like can be used. As the water-miscible organic solvent, an organic solvent (lower alcohol or the like) that can be uniformly mixed with water can be used. From the viewpoint of preventing the organic solvent from remaining in the polymer particles as much as possible, an aqueous solvent in which 80% by volume or more of the aqueous solvent is water is preferable, and an aqueous solvent in which 90% by volume or more of the aqueous solvent is water is more preferable. An aqueous solvent in which 95% by volume or more of the aqueous solvent is water is more preferable, an aqueous solvent substantially composed of water (an aqueous solvent in which 99.5% by volume or more is water) is particularly preferable, and water alone is the most preferable. preferable.

When polymerizing the raw material monomer component, for example, a polymerization initiator, irradiation with ultraviolet rays or radiation, application of heat, or the like is used, and it is preferable to use a polymerization initiator, and the raw material monomer component is used. From the viewpoint of efficiently reacting and sufficiently reducing the remaining monomers, a polymerization initiator (redox type polymerization initiator) in which an oxidizing agent and a reducing agent are combined is preferable.

The hydrolysis of the polymer particles of the present disclosure can be carried out by adding, for example, a basic aqueous solution such as an aqueous solution of sodium hydroxide, an aqueous solution of ammonia, or an aqueous solution of cyclohexylamine. Further, partial neutralization or complete neutralization can be performed by appropriately adding an acid to the hydrolyzed solution. By hydrolysis and neutralization, the group corresponding to R ¹ of the formula (1) can be changed to a hydrogen atom, an alkali metal atom, or ammonium. By adjusting the amount of acid or base used during polymerization, hydrolysis, and neutralization, or by adjusting the ratio of the monomer unit in which R1 is a hydrogen atom, the pH of the polymer particles and the hydrophilicity of the particle surface are adjusted. Since the properties can be easily adjusted, the compounding stability, water whitening resistance, and stain resistance of the aqueous resin composition for coatings of the present disclosure can be improved.

[Aqueous resin composition for paint of the present disclosure]
The aqueous resin composition for paints of the present disclosure comprises the polymer particles of the present disclosure. The content of the polymer particles of the present disclosure in the aqueous resin composition for paint of the present disclosure is preferably 0.2% by mass or more, more preferably 0.5% by mass or more, and 1% by mass or more. Is more preferable. Further, the content of the polymer particles of the present disclosure in the aqueous resin composition for paint of the present disclosure is preferably 20% by mass or less, more preferably 10% by mass or less, and 5% by mass or less. Is even more preferable. By including it in the above range, the compounding stability, water whitening resistance, and stain resistance of the aqueous resin composition for paints of the present disclosure tend to be improved.

The aqueous resin composition for paints of the present disclosure preferably contains an aqueous solvent. The content of the aqueous solvent in the aqueous resin composition for paint of the present disclosure is preferably 30% by mass or more, more preferably 35% by mass or more, and more preferably 40% by mass or more, from the viewpoint of improving handleability. Is more preferable. Further, the content of the aqueous solvent in the aqueous resin composition for paint of the present disclosure is preferably 70% by mass or less, more preferably 65% by mass or less, from the viewpoint of improving the productivity at the time of coating. , 60% by mass or less is more preferable.

The aqueous resin composition for paint of the present disclosure preferably contains one or more kinds of resins selected from acrylic resin, urethane resin, silicon resin, fluororesin, rubber, and polyester resin. The content of the resin in the aqueous resin composition for paints of the present disclosure is preferably 30% by mass or more, more preferably 35% by mass or more, and more preferably 40% by mass, from the viewpoint of improving productivity at the time of coating. It is more preferably mass% or more. Further, the content of the above resin in the aqueous resin composition for paint of the present disclosure is preferably 70% by mass or less, more preferably 65% by mass or less, and more preferably 60% by mass from the viewpoint of improving handleability. % Or less is more preferable.

The aqueous resin composition for paints of the present disclosure may contain other additives such as wetting agents, thickeners, preservatives, stabilizers, desiccants, dispersants and the like.

The aqueous resin composition for paint of the present disclosure is not particularly limited, but is preferably produced by comprising a step of mixing the polymer particle aqueous dispersion of the present disclosure with the emulsion of the above resin. The aqueous resin composition for paint may be produced by including one or more steps such as a concentration step, a dilution step, and a filtration step in addition to the above-mentioned mixing step.

[Use of the aqueous resin composition for paints of the present disclosure]
The water-based resin composition for paint of the present disclosure can be preferably used as a top coat paint or an undercoat paint for exteriors of structures used outdoors such as building materials, buildings / buildings, cars, ships, etc. May be used as.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "part" means "part by mass" and "%" means "% by mass".

<Volume average particle size>
The fine particle dispersion diluted with ion-exchanged water is measured using a light scattering particle size distribution measuring machine (“Zetasizer Ultra” manufactured by Spectris), and the volume average particle diameter (nm) of the fine particles is determined by a dynamic light scattering method. I asked.

<Formulation stability test>
The state of the samples of Examples and Comparative Examples after compounding was visually evaluated.
(Evaluation criteria)
〇: Good dispersibility.
×: Gelation, deposits.
(Comprehensive evaluation criteria)
〇: All 10 types are 〇 in the compounding stability evaluation.
×: Those with even one × in the compounding stability evaluation.

<Water whitening resistance test>
(Creation of coating film)
The evaluation sample obtained above was applied to a black acrylic plate [manufactured by Nippon Test Panel Co., Ltd., length: 150 mm, width: 75 mm, thickness: 3 mm] with a 6 mil applicator, and in an atmosphere of 23 ° C for one day. A test plate was prepared by drying.
(evaluation)
The E value (E0) of the test plate obtained above was measured with a colorimeter [manufactured by Nippon Denshoku Kogyo Co., Ltd., trade name: spectroscopic colorimeter SE-2000], and the test plate was further heated to 50 ° C. After immersing it in the prepared warm water for 4 hours, it was pulled up from the warm water, the water was wiped off with a Kim towel [manufactured by Nippon Paper Crecia Co., Ltd.], and the E value (E1) was measured with the colorimeter within 1 minute.
Next, the change value of the E value was obtained based on the following formula (1), and the hot water whitening resistance was evaluated based on the following evaluation criteria.

<Carbon contamination test>
(Preparation of carbon dispersion)
Add 5 parts of glass beads (diameter: 1 mm) to 95 parts of ion-exchanged water, and add 5 parts of carbon black [manufactured by Mitsubishi Chemical Corporation, trade name: MA-100] while stirring at a rotation speed of 500 rpm with a homodisper. did. After the addition, the rotation speed was dispersed at 2500 rpm for 30 minutes. After dispersion, the glass beads were removed by filtration through a 60-mesh wire mesh, and then used as a carbon black dispersion.
(Creation of coating film)
Apply the evaluation sample obtained above to a white acrylic plate [manufactured by Nippon Test Panel Co., Ltd., length: 150 mm, width: 75 mm, thickness: 2 mm] with a 6 mil applicator, and apply it in an atmosphere of 23 ° C for one day. A test plate was prepared by drying.
(evaluation)
After drying the coating film, the initial E value (E0) of the test plate was measured with a colorimeter [manufactured by Nippon Denshoku Kogyo Co., Ltd., product number: ZE-6000], and the carbon dispersion was applied with a 20 mil applicator. It was dried for 24 hours. After drying, the carbon black dispersion was washed away with running water and a brush [pig hair, hair length 40 mm], and the E value (E1) was measured with respect to the test plate with the color difference meter.
Next, the change value of the E value was obtained based on the following formula (2), and the stain resistance was evaluated.

[Synthesis of polymer particles]
<Manufacturing example A1>
Anionic reactive emulsifier Adecaria Soap SR-20 containing 1378 parts by mass of deionized water and ether sulfate type ammonium salt as the main ingredients in a first stainless steel reaction kettle equipped with a stirrer, thermometer and cooler (1378 parts by mass of deionized water) 100% by mass of active ingredient, manufactured by ADEKA Corporation) diluted to 10% by mass of active ingredient with ion-exchanged water (hereinafter referred to as "SR-20 (10% by mass of active ingredient)") 0.96 parts by mass is added, and the internal temperature is added. Was raised to 75 ° C. and kept at the same temperature. On the other hand, in a second reaction kettle different from the first reaction kettle, 50 parts by mass of methyl methacrylate (hereinafter referred to as "MMA") and 50 parts by mass of normal butyl acrylate (hereinafter referred to as "BA") are charged and simply charged. 100 parts by mass of the weight composition A was prepared. Further, in a third reaction kettle different from the first reaction kettle and the second reaction kettle, 90 parts by mass of methyl 2-hydroxymethylacrylate (hereinafter referred to as "RHMA") and divinylbenzene (Nippon Steel & Sumikin Chemical Co., Ltd.) , Divinylbenzene with a purity of 81%, hereinafter referred to as "DVB810") was mixed with 10 parts by mass to prepare 100 parts by mass of the monomer composition B.

Next, after replacing the inside of the first reaction kettle with nitrogen gas, 100 parts by mass of the monomer composition A, 20 parts by mass of hydrogen peroxide solution (concentration 3.35% by mass), and an L-ascorbic acid aqueous solution ( 20 parts by mass (concentration: 5.0% by mass) was added to the first reaction vessel to carry out the initial polymerization reaction. Subsequently, 100 parts by mass of the monomer composition B, 100 parts by mass of hydrogen peroxide solution (concentration 0.83% by mass), and 100 parts by mass of L-ascorbic acid aqueous solution (concentration 1.25% by mass), SR-20. (10% by mass of active ingredient) 100 parts by mass of a mixed composition of 7.04 parts by mass, 0.36 parts by mass of an aqueous ammonia (concentration 28% by mass) and 92.6 parts by mass of ion-exchanged water, from different inlets. , The mixture was uniformly added dropwise to the first reaction vessel over 3 hours. After completion of the dropping, the internal temperature of the first reaction kettle was maintained at 75 ° C., the temperature was maintained at the same temperature for 2 hours for aging, and then the reaction solution was cooled to obtain a polymer aqueous dispersion in which the polymer was dispersed. rice field. Add 10 parts by mass of the aqueous dispersion of the polymer obtained above and 0.19 parts by mass of an aqueous ammonia solution (concentration 25.0% by mass) as a basic aqueous solution to the first reaction vessel, and stir at 25 ° C. overnight. To obtain a polymer particle aqueous dispersion (1a) in which the partially hydrolyzed polymer particles (1) were dispersed.

<Manufacturing example A2>
A polymer in which partially hydrolyzed polymer particles (2) are dispersed in the same manner as in Production Example A1 except that the monomer composition A is changed from 50 parts by mass of MMA and 50 parts by mass of BA to 100 parts by mass of BA. A particulate aqueous dispersion (2a) was obtained.

<Manufacturing example A3>
Adecaria Soap SR-20, an anionic reactive surfactant containing 832.0 parts by mass of deionized water and an ether sulfate type ammonium salt as main components, in a stainless steel reaction kettle equipped with a stirrer, a thermometer and a cooler. 100% by mass of active ingredient, manufactured by ADEKA Corporation) diluted to 25.0% by mass of active ingredient with ion-exchanged water (hereinafter referred to as "SR-20 (25.0% by mass of active ingredient)") is 0.96% by mass. In addition, the internal temperature was raised to 75 ° C. and kept at the same temperature. On the other hand, 180 parts by mass of RHMA and 20 parts by mass of DVB810 were mixed in a container different from the above reaction kettle to prepare 200 parts by mass of the monomer composition. Next, after replacing the inside of the reaction vessel with nitrogen gas, 40 parts by mass of the above-mentioned monomer composition, 21 parts by mass of hydrogen peroxide solution (hydrogen peroxide concentration 1.28% by mass), and an L-ascorbic acid aqueous solution. (L-ascorbic acid concentration 1.90% by mass) 21 parts by mass was added to the above reaction kettle to carry out an initial polymerization reaction. Subsequently, 160 parts by mass of the balance of the above-mentioned monomer composition, 479 parts by mass of hydrogen peroxide solution (hydrogen peroxide concentration 0.22% by mass), and L-ascorbic acid aqueous solution (L-ascorbic acid concentration 0.33% by mass). %) 486.04 parts by mass of a mixed composition of 479 parts by mass and SR-20 (25.0% by mass of the active ingredient) 7.04 parts by mass is uniformly added dropwise to the reaction vessel from different inlets over 4 hours. did. After completion of the dropping, the internal temperature was raised to 85 ° C., and the mixture was kept at the same temperature for 2 hours for aging, and then the reaction solution was cooled to obtain a polymer particle dispersion in which the polymer particles were dispersed. Add 10 parts by mass of the aqueous dispersion of the polymer obtained above and 0.38 parts by mass of an aqueous ammonia solution (concentration 25.0% by mass) as a basic aqueous solution to the first reaction vessel, and stir at 25 ° C. overnight. To obtain a polymer particle aqueous dispersion (3a) in which the partially hydrolyzed polymer particles (3) were dispersed.

<Manufacturing example A4>
A 10 L glass reactor equipped with a stirrer, a dropping device and a thermometer was charged with 4266.5 g of methyl alcohol as an organic solvent and 666.0 g of 28 wt% aqueous ammonia (water and catalyst) while stirring. The liquid temperature was adjusted to 20 ± 0.5 ° C. On the other hand, a solution prepared by dissolving 666.0 g of tetramethoxysilane as a silicon compound in 533.0 g of methyl alcohol was charged into the dropping device. Then, the solution was dropped from the dropping device over 1 hour. After completion of the dropping, the mixture was further stirred for 1 hour to hydrolyze and condense tetramethoxysilane to obtain a suspension of silica particles. The average particle size of the silica particles was 300 nm. The obtained suspension was dried using an instantaneous vacuum evaporator to take out powdery silica particles (4). As the instantaneous vacuum drying device, a Cracks System 8B type (manufactured by Hosokawa Micron Co., Ltd.) was used. Further, as the drying conditions, a heating tube temperature of 175 ° C. and a decompression degree of 200 torr were adopted. The above-mentioned instantaneous vacuum evaporator includes a stainless steel pipe having an inner diameter of 8 mm and a length of 9 m covered with a jacket to which heated steam is supplied, a supply unit for supplying a suspension to one end of the steel pipe, and the other end of the steel pipe. It was equipped with a powder collection chamber in a reduced pressure state, which was connected to a section and provided with a bag filter for separating powder and steam. Then, the suspension supplied from the supply unit is heated when passing through the steel pipe and separated into powder and steam, the powder is collected by the bag filter, the steam is condensed, and then the apparatus. It was configured to be discharged to the outside. By dispersing the powdery silica particles (4) in ion-exchanged water, an aqueous dispersion of silica particles (4a) having a particle concentration of 22 wt% was obtained.

[Synthesis of paint resin]
<Manufacturing example B1>
685 parts of deionized water was placed in a flask equipped with a dropping funnel, a stirrer, a nitrogen gas introduction tube, a thermometer and a reflux condenser. On the other hand, 300 parts of deionized water, 200 parts of emulsifier [manufactured by ADEKA Corporation, trade name: 25% aqueous solution of Adecaria Soap SR-10], 365 parts of 2-ethylhexyl acrylate, 625 parts of methyl methacrylate in the dropping funnel. And a pre-emulsion for dropping consisting of 10 parts of 2-hydroxyethyl methacrylate was prepared.
The temperature was raised to 80 ° C. while gently blowing nitrogen gas into the flask, 50 parts of a 5% ammonium persulfate aqueous solution was added into the flask, and the dropping preemulsion was added dropwise over 2 hours to obtain an acrylic emulsion.
After completion of the dropping, the contents of the flask were maintained at 80 ° C. for 60 minutes, 25% aqueous ammonia was added into the flask, the pH was adjusted to 9, and the polymerization was completed.
The obtained reaction solution was cooled to room temperature and then filtered through a wire mesh of 300 mesh (JIS mesh, the same applies hereinafter) to obtain a resin emulsion (B1) having a non-volatile content of 47% by mass.

[Preparation of paint composition]
<Example 1-1>
An aqueous resin composition was prepared by mixing 100 parts by mass of the resin emulsion obtained in Production Example B1 and 19.5 parts by mass of the polymer particle aqueous dispersion (1a) obtained in Production Example A1. At this time, the mass ratio (resin emulsion / polymer particles) of the non-volatile content of the resin emulsion and the non-volatile content of the polymer particle aqueous dispersion was 100/4.
To the aqueous resin composition, 8.4 parts by mass of 2,2,4-trimethyl-1,3-pentanediol isobutylate [manufactured by JNC Co., Ltd., product number: CS-12] was added as a film forming aid. After stirring with a homodisper at a rotation speed of 1000 rpm for 10 minutes, diluted water was added so that the non-volatile content was 47%. Further, by adding 2.4 parts by mass of a 5% aqueous solution of a thickener [manufactured by ADEKA Corporation, trade name: Adecanol UH-420] to the mixture, stirring in that state for 30 minutes, and filtering with a 300 mesh wire mesh. , Samples were prepared.

<Examples 2-1 and 3-1>
In Example 1, a sample was prepared in the same manner as in Example 1 except that the polymer particle aqueous dispersion (1a) was changed to (2a) and (3a).

<Comparative Example 1-1>
In Example 1, a sample was prepared in the same manner as in Example 1 except that the polymer particle aqueous dispersion (1a) was changed to the silica particle aqueous dispersion (4a) synthesized in Production Example A4.

<Comparative Example 2-1>
In Example 1, a sample was prepared in the same manner as in Example 1 except that the polymer particle aqueous dispersion (1a) was changed to silica sol (Snowtex N manufactured by Nissan Chemical Industries, Ltd.).

<Comparative Example 3-1>
In Example 1, a sample was prepared in the same manner as in Example 1 except that the polymer particle aqueous dispersion (1a) was changed to silica sol (Snowtex AK manufactured by Nissan Chemical Industries, Ltd.).

<Comparative Example 4-1>
In Example 1, a sample was prepared in the same manner as in Example 1 except that the polymer particle aqueous dispersion (1a) was changed to silica sol (Snowtex 30 manufactured by Nissan Chemical Industries, Ltd.).

<Comparative Example 5-1>
In Example 1, a sample was prepared in the same manner as in Example 1 except that the polymer particle aqueous dispersion (1a) was changed to silica sol (Snowtex O manufactured by Nissan Chemical Industries, Ltd.).

<Examples 1-2 to 3-10, Comparative Examples 1-2 to 5-10>
In Example 1-1, the resin emulsion / polymer particles were changed from 100/4 to 100/10, and the resin emulsion was changed from the resin emulsion obtained in Production Example B1 to the paint resin shown in Table 1. Samples were prepared in the same manner as in Example 1-1, except that the polymer particles were changed from the polymer particle aqueous dispersion (1a) obtained in Production Example A1 to the particles shown in Table 1.

From the results of Tables 1 and 2, it was clarified that the aqueous resin composition for paint of the present disclosure is excellent in compounding stability, water whitening resistance, and stain resistance.

Claims (5)

An aqueous resin composition for coating material containing polymer particles, wherein the polymer particles include a structural unit represented by the following general formula (1) and a structural unit derived from a polyfunctional ethylenically unsaturated monomer. Is.

(In the general formula (1), R1 represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom, an alkali metal atom, or ammonium.) The aqueous resin composition for paint according to claim 1, which comprises polymer particles having a glass transition temperature of 80 ° C. or higher. The aqueous resin composition for paint according to claim 1 or 2, wherein at least a part of R ¹ is an alkali metal atom or ammonium in the general formula (1). The aqueous resin composition for paint according to any one of claims 1 to 3, which contains polymer particles having 50% by mass or more of structural units represented by the general formula (1). The water-based resin composition for paint according to any one of claims 1 to 4, which comprises one or more resins selected from acrylic resin, urethane resin, rubber, and polyester resin.