JP7231915B1 - Fluorine-containing aqueous resin particle dispersion and method for producing the same - Google Patents

Abstract

An object of the present invention is to provide a fluorine-containing aqueous resin particle dispersion which is excellent in long-term storage stability.
[Solution]
A fluorine-containing aqueous resin particle dispersion containing an amphiphilic polymer and resin particles comprises an amphiphilic polymer comprising a copolymer of a hydrophobic monomer and a hydrophilic monomer, and the amphiphilic polymer. and resin particles containing at least a fluorine-containing (meth)acrylic monomer as a structural unit, which are covered with a protective layer formed of molecules. The average particle size of the fluorine-containing aqueous resin particle dispersion is 20 to 100 nm. Here, the average particle size of the fluorine-containing aqueous resin particle dispersion is measured using a dynamic light scattering method.

[Selection figure] None

Description

TECHNICAL FIELD The present invention relates to a fluorine-containing aqueous resin particle dispersion and a method for producing the same.

Resin emulsions containing fluorine-containing (meth)acrylic monomers as structural units are known as water-based paints with excellent antifouling properties for wallpaper materials and the like. Also, fluorine is known to be very hydrophobic. Therefore, when the introduction ratio of the fluorine-containing (meth)acrylic monomer in the aqueous dispersion medium is relatively high, it is very difficult to obtain a resin emulsion by emulsion polymerization.

Therefore, in Patent Document 1, a fluorine-containing acrylic resin composition obtained by solution polymerization is neutralized, and water is added for phase inversion to obtain a (meth)acrylic monomer in an aqueous emulsion. A fluorine-containing acrylic resin emulsion is obtained by polymerizing. In Patent Documents 2 to 5, microemulsification of oil droplets of a monomer component containing a fluorine-containing (meth)acrylic monomer is performed by forced emulsification using a high-pressure homogenizer or an ultrasonic disperser, and mini-emulsion polymerization is performed. A fluorine-containing acrylic resin emulsion is obtained by performing. Furthermore, Patent Documents 6 and 7 disclose a method in which a microemulsion is synthesized in the presence of an emulsifier and a fluorine-containing solvent, and a fluorine-based monomer that is gaseous at room temperature is polymerized while introducing under pressure, with a particle size of about 30 nm or less. of ultrafine particles are synthesized.

JP-A-03-269184 JP-A-11-172190 Japanese Patent Application Laid-Open No. 2000-110069 Japanese Patent Publication No. 2011-515503 JP 2013-224418 A Japanese Patent Publication No. 10-512303 Japanese translation of PCT publication No. 2013-540869

However, the particle size of the resin particles of each resin emulsion obtained by using the methods of Patent Documents 1 to 5 is large, for example, 100 to 200 nm or more. Moreover, the specific gravity of the resin particles obtained by copolymerizing a fluorine-containing (meth)acrylic monomer having a large specific gravity is increased. In other words, in Patent Documents 1 to 5, since resin particles having a large specific gravity settle in an aqueous emulsion, there is a problem that the long-term storage stability of the resin emulsion is not sufficient. Moreover, in Patent Documents 6 and 7, there is a problem that a resin emulsion cannot be synthesized using a fluoromonomer that is liquid at room temperature.

Accordingly, an object of the present invention is to provide a fluorine-containing aqueous resin particle dispersion that is excellent in long-term storage stability.

In order to achieve the object of the present invention, the present invention provides a fluorine-containing aqueous resin particle dispersion containing resin particles, which is an amphiphilic polymer comprising a copolymer of a hydrophobic monomer and a hydrophilic monomer. The average particle diameter of the fluorine-containing aqueous resin particle dispersion is 20 to 60 nm, wherein the average particle size of the fluorine-containing aqueous resin particle dispersion is measured using a dynamic light scattering method, and the amphiphilic polymer is the total mass of the amphiphilic polymer. In contrast, a structural unit derived from a carboxy group-containing polymerizable monomer having a carboxy group as the hydrophilic monomer is contained in an amount of 5% by mass or more and 20% by mass or less, and the hydrophobic monomer is methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, styrene, 2-(perfluorohexyl ) ethyl acrylate (C6SFA) , and the hydrophilic monomer includes 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (meth) ) contains at least one of acrylic acid, (meth)acrylonitrile, (meth)acrylamide, and diacetoneacrylamide, and the fluorine-containing aqueous resin particle dispersion does not contain an emulsifier, a surfactant, or a dispersant.

According to the present invention, a fluorine-containing aqueous resin particle dispersion excellent in long-term storage stability can be provided.

Embodiments will be described in detail below. It should be noted that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more of the features described in the embodiments may be combined arbitrarily.

<Fluorine-Containing Aqueous Resin Particle Dispersion>
The fluorine-containing aqueous resin particle dispersion of the present invention comprises an amphiphilic polymer comprising a copolymer of a hydrophobic monomer and a hydrophilic monomer, and a protective layer formed of the amphiphilic polymer. and a resin particle containing at least a fluorine-containing (meth)acrylic monomer as a structural unit to be covered.

In conventional water-based resin emulsions, regardless of whether the shape of the resin particles is a so-called single type or a core-shell type, around the resin particles, about several mass% to tens of mass% The presence of the emulsifier or dispersant layer keeps the resin particles in a stable dispersed state.

On the other hand, the water-based resin emulsion (fluorine-containing water-based resin particle dispersion) of the present invention is prepared by polymerizing resin particles in which a monomer component containing a fluorine-containing (meth)acrylic monomer is polymerized without using an emulsifier or the like. By covering with a protective layer of a medium polymer, it is possible to maintain a stable dispersed state of the resin particles.

The aqueous resin emulsion (fluorine-containing aqueous resin particle dispersion) of the present invention is obtained by the following steps. First, before polymerization of a monomer component containing a fluorine-containing (meth)acrylic monomer, the amphipathic polymer surrounds the monomer component for forming resin particles. Then, in a state in which the amphiphilic polymer surrounds the monomer component, the monomer component is polymerized to form a resin particle covered with a protective layer of the amphiphilic polymer. As a result, an aqueous resin emulsion (fluorine-containing aqueous resin particle dispersion) containing resin particles uniformly dispersed in an aqueous dispersion medium is obtained.

The amphiphilic polymer contains structural units derived from a carboxy group-containing polymerizable monomer having a carboxy group in an amount of 5% by mass or more and 20% by mass or less with respect to the total mass of the amphiphilic polymer. Therefore, the protective layer (that is, the amphipathic polymer layer) has a function of dispersing the resin particles in the aqueous resin emulsion like an emulsifier or dispersant. As a result, even if the water-based resin emulsion does not contain an emulsifier or dispersant for dispersing the resin particles, it is possible to keep the resin particles in a stable dispersed state by covering the resin particles with the protective layer. .

(Average particle size)
The average particle size of the fluorine-containing aqueous resin particle dispersion is 20 to 100 nm, preferably 20 to 80 nm, more preferably 20 to 60 nm, from the viewpoint of suppressing sedimentation of the resin particles in the aqueous dispersion medium. . Here, when the average particle diameter of the fluorine-containing aqueous resin particle dispersion is 100 nm or more, the fluorine-containing aqueous resin particles tend to settle in the aqueous dispersion medium, so that the storage stability of the fluorine-containing aqueous resin particle dispersion is improved. may decrease.

The average particle size of the fluorine-containing aqueous resin particle dispersion in the present specification is the volume average particle size of the fine particles measured by the dynamic light scattering method, and is 50% of the cumulative distribution of the particle size distribution. Particle size (d50: median diameter). The 50% particle size is measured using, for example, a particle size distribution measuring device (manufactured by Otsuka Electronics Co., Ltd., trade name “Concentrated Particle Size Analyzer FPAR-1000”).

The fluorine-containing aqueous resin particle dispersion contains the amphipathic polymer in an amount of 30% by mass or more and 300% by mass or less with respect to the total mass of the resin particles. Here, when the fluorine-containing aqueous resin particle dispersion contains less than 30% by mass of the amphipathic polymer with respect to the total mass of the resin particles, the resin particles cannot be kept in a stable dispersed state. On the other hand, when the fluorine-containing aqueous resin particle dispersion contains 300% by mass or more of the amphipathic polymer with respect to the total mass of the resin particles, aggregates are generated, which lowers production stability. There is

<Amphiphilic polymer>
An amphiphilic polymer is a polymer composed of a copolymer of a hydrophobic monomer and a hydrophilic monomer, and exhibits affinity for both organic solvents and water. Further, the amphipathic polymer can easily take the emulsified state of O/W type emulsion or W/O type emulsion by arbitrarily changing the ratio of the organic solvent and water.

The most suitable amphiphilic polymer in the present invention has both the property of being soluble in organic solvents and the property of dispersing in water. When amphiphilic macromolecules dissolve in organic solvents, clear liquids are obtained. On the other hand, when the amphiphilic polymer is dispersed in water, a dispersion of the amphiphilic polymer is obtained. Here, regardless of whether the appearance of the solution is transparent or opaque, the particle size of the amphiphilic polymer can be measured by observing the scattered light in the particle size measurement using the dynamic light scattering method. It refers to an aqueous liquid.

The types and blending ratios of the hydrophobic monomer and the hydrophilic monomer determine the above two properties of the amphiphilic polymer (the property of being soluble in organic solvents and the property of dispersing in water). Any combination that satisfies the conditions is acceptable, and is not particularly limited.

(Hydrophobic monomer)
The hydrophobic monomer is not particularly limited as long as it is a monomer whose homopolymer solubility parameter (SP value) is less than 11.0. Hydrophobic monomers are preferably (meth)acrylic monomers. Here, the SP value is a physical property value defined by the square root of the cohesive energy density calculated from the following formula (1).
δ (SP value) = (ΣEcoh/ΣV) ^1/2 (1)

The SP value is calculated by the Fedors estimation method from the molecular structure of the hydrophobic monomer, and is calculated based on the cohesive energy density and molar molecular volume. ΣEcoh represents the sum of the cohesive energy densities of each functional group of a substance. ΣV represents the sum of molar molecular volumes. The unit of cohesive energy is generally J/mol, but the SP value (cal/mol) obtained by dividing the SP value (unit: J/mol) by a factor of 4.19 is used herein. As the cohesive energy inherent to atomic groups and groups and the molar molecular volume constant, the numerical values described in "RF Fedors, Polym. Eng. Sci., 14[2], 147-154 (1974)" can be used.

Hydrophobic monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, styrene including. The hydrophobic monomer may contain one of the above alone or two or more.

(Hydrophilic monomer)
The hydrophilic monomer is not particularly limited as long as it is a monomer whose homopolymer SP value is 11.0 or more. Since the amphipathic polymer is obtained by solution polymerization using an organic solvent, it is desirable that the hydrophilic monomer is soluble in the organic solvent.

The amphipathic polymer contains a structural unit derived from a carboxy group-containing polymerizable monomer having a carboxy group. The amphiphilic polymer contains a structural unit derived from a monomer having cross-linking reactivity other than the structural unit derived from the carboxy group-containing polymerizable monomer. Here, the monomer having cross-linking reactivity includes diacetone acrylamide.

As used herein, the term "structural unit" means a unit of a monomer that forms an amphipathic polymer. "Structural unit derived (from a monomer)" means, for example, a structural unit in which a polymerizable double bond (C=C) in a monomer is cleaved to become a single bond (-C-C-), etc. is mentioned. In addition, in this specification, homopolymerization and copolymerization may be simply referred to as "polymerization" without any particular distinction.

From the viewpoint of maintaining the resin particles in a stable dispersed state, the amphiphilic polymer has 5 structural units derived from a carboxy group-containing polymerizable monomer having a carboxy group with respect to the total mass of the amphiphilic polymer. It is contained in an amount of not less than 20% by mass. In an aqueous solution of an amphiphilic polymer (preferably a neutralized aqueous solution of an amphiphilic polymer) containing 5% by mass or more and 20% by mass or less of a structural unit derived from a carboxy group-containing polymerizable monomer By polymerizing the monomer component that forms the resin particles in (1), it is possible to obtain a protective layer that can cover the resin particles and maintain the resin particles in a stable dispersed state in the aqueous dispersion medium.

In addition, since the amphiphilic polymer contains the carboxyl group-containing monomer in the amount specified above, the amphiphilic polymer partially dissolves in the aqueous liquid, and the hydrophilicity of the amphiphilic polymer increases. increase. This makes it easier for the amphiphilic polymer to surround the monomer component forming the resin particles, so that part or all of the carboxy groups in the structural units derived from the carboxy group-containing polymerizable monomer are neutralized. preferably.

The structural unit derived from the reactive group-containing polymerizable monomer in the amphiphilic polymer may be composed only of structural units derived from the carboxy group-containing polymerizable monomer. Alternatively, the structural unit derived from the reactive group-containing polymerizable monomer in the amphiphilic polymer includes a structural unit derived from the carboxy group-containing polymerizable monomer and other reactive group-containing polymerizable monomers. It may be composed of a structural unit derived from the body.

Hydrophilic monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (meth)acrylic acid, (meth)acrylonitrile, (meth)acrylamide, Contains diacetone acrylamide. The hydrophilic monomer may contain one type of the above alone or two or more types.

(Organic solvent)
The organic solvent is not particularly limited as long as it has the property of dissolving the hydrophobic monomer, hydrophilic monomer and amphipathic polymer. The organic solvent is preferably a lower fatty acid ester-based organic solvent from the viewpoint of solubility of the hydrophobic monomer, hydrophilic monomer, and amphipathic polymer.

Lower fatty acid esters include ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate and the like. The organic solvent may contain one type of the above alone or two or more types.

<Resin particles>
From the viewpoint of enhancing the water resistance of the film formed from the dispersion of fluorine-containing aqueous resin particles, the resin particles contain a fluorine-containing (meth)acrylic monomer as a structural unit in an amount of 40% by mass with respect to the total mass of the resin particles. Above, it contains in 100 mass % or less.

In this specification and the like, "resin particles" are resin particles in which a monomer component containing at least a (meth)acrylic acid ester as a polymerizable monomer is polymerized, and at least a structure derived from the (meth)acrylic acid ester. have units. In this specification and the like, the term “(meth)acryl” means that both terms “acryl” and “methacryl” are included. Similarly, the term "(meth)acrylate" is meant to include both the terms "acrylate" and "methacrylate." The resin particles may be homopolymer particles obtained by polymerizing one kind of polymerizable monomer ((meth)acrylic acid ester), or two or more kinds of polymerizable monomers containing (meth)acrylic acid ester. may be copolymer particles obtained by copolymerization.

(Meth)acrylic acid esters include, for example, (meth)acrylic acid alkyl esters, fluorine-containing (meth)acrylic monomers, (meth)acrylic acid hydroxyalkyl esters, (meth)acrylic acid alkoxyalkyl esters, (meth) It includes aralkyl acrylates, aryl (meth)acrylates, and other (meth)acrylates. The (meth)acrylic acid ester may contain one of the above or two or more of them. The (meth)acrylic acid ester preferably contains at least a fluorine-containing (meth)acrylic monomer as a monomer component forming the resin particles.

(Meth)acrylic acid alkyl esters, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate , tert-butyl (meth)acrylate, sec-butyl (meth)acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate ) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-undecyl (meth) acrylate, n-dodecyl Linear or branched alkyl such as (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate (meth)acrylic acid alkyl esters having groups; and cyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and dicyclopentenyl (meth)acrylate. ) including alicyclic (meth)acrylic acid alkyl esters such as acrylates. The (meth)acrylic acid alkyl ester may contain one of the above alone or two or more of them. The (meth)acrylic acid alkyl ester is a (meth)acrylic acid alkyl ester having a linear or branched alkyl group having 1 to 18 carbon atoms (more preferably 1 to 12 carbon atoms) among the above. Preferably.

Fluorine-containing (meth)acrylic monomers include, for example, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3,3-pentafluoropropyl (meth)acrylate, 2-(per fluorobutyl)ethyl (meth)acrylate, 2-(perfluorohexyl)ethyl (meth)acrylate, 2-(perfluorooctyl)ethyl (meth)acrylate, 2-(perfluorodecyl)ethyl (meth)acrylate, 1H, 1H,3H-tetrafluoropropyl (meth)acrylate, 1H,1H,5H-octafluoropentyl (meth)acrylate, 1H,1H,7H-dodecafluoroheptyl (meth)acrylate, 1H-1-(trifluoromethyl)tri Including fluorinated alkyl (meth)acrylates such as fluoroethyl (meth)acrylate and 1H,1H,3H-hexafluorobutyl (meth)acrylate. The fluorine-containing (meth)acrylic monomer may contain one of the above alone or two or more of them.

(Meth)acrylic acid hydroxyalkyl esters are, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3- including hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate, etc. . The (meth)acrylic acid hydroxyalkyl ester may contain one type of the above alone or two or more types.

(Meth)acrylic acid alkoxyalkyl esters are, for example, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, ethoxyethoxyethyl (meth)acrylate, and 2- Including phenoxyethyl (meth)acrylate and the like. The (meth)acrylic acid alkoxyalkyl ester may contain one type of the above alone or two or more types.

(Meth)acrylic acid aralkyl esters include, for example, benzyl (meth)acrylate, 2-phenylethyl (meth)acrylate, methylbenzyl (meth)acrylate, naphthylmethyl (meth)acrylate, and the like. The (meth)acrylic acid aralkyl ester may contain one type of the above alone or two or more types.

(Meth)acrylic acid aryl esters include, for example, phenyl (meth)acrylate, 4-hydroxyphenyl (meth)acrylate, tolyl (meth)acrylate, naphthyl (meth)acrylate, and the like. The (meth)acrylic acid aryl ester may contain one type of the above alone or two or more types.

Other (meth)acrylic acid esters are, for example, polyalkylene glycol (meth)acrylates such as polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and methoxypolyethylene glycol mono(meth)acrylate; 2- (Meth)acrylic acid alkyl esters having a halogen atom such as chloroethyl (meth)acrylate, trifluoroethyl (meth)acrylate, 2-(perfluorobutyl)ethyl (meth)acrylate, and perfluorooctylethyl (meth)acrylate; 2-(dimethylamino)ethyl (meth)acrylate, 2-(diethylamino)ethyl (meth)acrylate, and (meth)acrylate having an amino group such as 3-(dimethylamino)propyl (meth)acrylate; carboxyethyl (meth) acrylates and (meth) acrylic acid esters having a carboxy group such as carboxypentyl (meth) acrylate; glycidyl (meth) acrylate, glycerin mono (meth) acrylate, 2-methylglycidyl (meth) acrylate, and 3, (Meth) acrylic acid esters having an epoxy group such as 4-epoxycyclohexylmethyl (meth) acrylate and derivatives thereof; 2-sulfoethyl (meth) acrylate and 3-sulfopropyl (meth) acrylate having a sulfonic acid group meth)acrylate; 2-(phosphonooxy)ethyl (meth)acrylate having a phosphoric acid group; (meth)acrylate having an isocyanate group such as 2-isocyanatoethyl (meth)acrylate; tetrahydrofurfuryl (Meth) acrylates having a heterocyclic ring such as acrylates; include. Other (meth)acrylic acid esters may include one of the above alone or two or more.

The resin particles may be resin particles in which a monomer component containing the above-mentioned (meth)acrylic acid ester and other polymerizable monomer copolymerizable with the (meth)acrylic acid ester is polymerized. In this case, the resin particles can have a structural unit derived from the (meth)acrylic acid ester and a structural unit derived from another polymerizable monomer copolymerizable with the (meth)acrylic acid ester.

The other polymerizable monomer is preferably an unsaturated carboxylic acid-based monomer, and the resin particles preferably contain a structural unit derived from the unsaturated carboxylic acid-based monomer. In this specification and the like, unsaturated carboxylic acid-based monomers include unsaturated carboxylic acids and their anhydrides and monoesters.

Unsaturated carboxylic acid-based monomers include, for example, unsaturated carboxylic acids such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and citraconic acid; Anhydrides of unsaturated carboxylic acids; including monoesters of unsaturated carboxylic acids such as monomethyl maleate, monobutyl maleate, monomethyl itaconate, and monobutyl itaconate. The unsaturated carboxylic acid-based monomer may contain one of the above or two or more of them. Of the above unsaturated carboxylic acid-based monomers, (meth)acrylic acid is more preferable.

Polymerizable monomers other than unsaturated carboxylic acid-based monomers include unsaturated monomers having a nitrogen atom, styrene-based monomers, and the like. Polymerizable monomers other than unsaturated carboxylic acid monomers are preferably styrene monomers. The (meth)acrylic resin particles preferably contain a structural unit derived from a styrene monomer.

Unsaturated monomers having a nitrogen atom include, for example, unsaturated monomers having a cyano group such as acrylonitrile and methacrylonitrile; (meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide , N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-methylol (meth)acrylamide, N-butoxymethyl (meth)acrylamide, N-[2 -Dimethylaminoethyl](meth)acrylamide, N-[3-dimethylaminopropyl](meth)acrylamide, diacetoneacrylamide, 4-acryloylmorpholine, and acrylamide-based monomers such as 4-methacryloylmorpholine; N-vinylacetamide , and acetamide-based monomers having a vinyl group such as N-vinyl-N-methylacetamide; N-vinyl-2-pyrrolidone, 4-vinylpyridine, 1-vinylimidazole, 2-vinyl-2-oxazoline, and 2 -Nitrogen-containing heterocyclic compounds having a vinyl group such as isopropenyl-2-oxazoline. The unsaturated monomer having a nitrogen atom may contain one type of the above alone or two or more types.

Styrenic monomers include, for example, styrene, α-methylstyrene, o-, m-, p-methylstyrene, o-, m-, p-ethylstyrene, 4-tert-butylstyrene, o-, m- , p-hydroxystyrene, o-, m-, p-methoxystyrene, o-, m-, p-ethoxystyrene, o-, m-, p-chlorostyrene, o-, m-, p-bromostyrene, o-, m-, p-fluorostyrene, o-, m-, p-chloromethylstyrene, and the like. The styrenic monomer may contain one of the above alone or two or more of them. The styrenic monomer is preferably styrene.

Other polymerizable monomers include, in addition to the above-mentioned unsaturated carboxylic acid monomers, unsaturated monomers having a nitrogen atom, and styrene monomers, for example, vinyl monomers, unsaturated alcohols , vinyl ether-based monomers, vinyl ester-based monomers, unsaturated monomers having epoxy groups, and unsaturated monomers having sulfonic acid groups.

Vinyl-based monomers include, for example, vinyl chloride and vinyl fluoride.

Unsaturated alcohols include, for example, vinyl alcohol, allyl alcohol, and the like.

Vinyl ether monomers include, for example, methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, phenyl vinyl ether, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, and the like.

Vinyl ester monomers include, for example, vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caprylate, vinyl laurate, vinyl stearate, and vinyl versatate.

Unsaturated monomers having an epoxy group include allyl glycidyl ether and the like.

Unsaturated monomers having a sulfonic acid group include, for example, vinylsulfonic acid, styrenesulfonic acid, allylsulfonic acid, methallylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, and the like. Other polymerizable monomers may include one of the above alone or two or more of them.

Furthermore, the monomer component forming the resin particles can contain a monomer (crosslinkable monomer) that can function as a crosslinker as a polymerizable monomer. Crosslinkable monomers include monomers having two or more polymerizable unsaturated bonds. Crosslinkable monomers include, for example, 2-hydroxy-3-acryloyloxypropyl (meth)acrylate, ethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4- butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene Glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate , and difunctional (meth)acrylates such as glycerin di(meth)acrylate; polyfunctional ( meth)acrylate; allyl (meth)acrylate; divinylbenzene; and diallyl phthalate, and the like. The crosslinkable monomer may contain one of the above alone or two or more of them.

The crosslinkable monomers are 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-acryloxypropyl Contains silane coupling agents such as trimethoxysilane. The crosslinkable monomer may contain one of the above alone or two or more of them.

(Method for Producing Fluorine-Containing Aqueous Resin Particle Dispersion)
A fluorine-containing aqueous resin particle dispersion (hereinafter referred to as a dispersion) is prepared by adding a monomer component containing a fluorine-containing (meth)acrylic monomer to an aqueous solution of an amphiphilic polymer. It is produced by performing emulsion polymerization. The dispersion contains resin particles containing a fluorine-containing (meth)acrylic monomer as a structural unit, covered with a protective layer made of an amphipathic polymer.

As used herein, "soap-free" means not using emulsifiers, surfactants, and dispersants. Moreover, "microemulsion polymerization" means a polymerization method in which a polymerization reaction is performed after preparing a microemulsion using a monomer as an oil phase component. "Microemulsion" means an emulsion in which resin particles having an average particle size of 100 nm or less are easily dispersed without strong stirring. The method for producing the fluorine-containing aqueous resin particle dispersion (manufacturing steps 1 to 3) will be described below.

(Manufacturing Step 1: Preparation of Aqueous Liquid of Amphiphilic Polymer)
An aqueous solution of an amphipathic polymer is obtained by carrying out the production step 1. That is, in the production process 1, after synthesizing an amphiphilic polymer by solution polymerization of a hydrophobic monomer and a hydrophilic monomer in a solvent, the polymer is reversely emulsified in an aqueous phase after neutralization with an alkaline substance, It includes the step of preparing an aqueous solution of the medium polymer.

The solvent is preferably a non-reactive solvent. Solvents include, for example, aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as hexane, cyclohexane, heptane, and octane; capryl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, isostearyl Higher alcohols having 8 or more carbon atoms (more preferably 8 to 22 carbon atoms) such as alcohol, oleyl alcohol, and behenyl alcohol; ester solvents such as ethyl acetate, propyl acetate, and butyl acetate; methyl isobutyl ketone, methyl butyl ketone, etc. including ketone-based solvents, etc. The solvent may contain one of the above alone or two or more. In order to obtain an aqueous amphiphilic polymer solution after removing the solvent in the above step, the solvent is preferably a solvent having a boiling point of less than 100° C. or a solvent capable of azeotroping with water.

The amount of the solvent used is 0 to 300 parts by mass with respect to 100 parts by mass of the monomer component, which is the sum of the hydrophobic monomer and the hydrophilic monomer used to synthesize the amphipathic polymer. preferably 30 to 200 parts by mass, even more preferably 50 to 150 parts by mass.

When polymerizing the monomer components of a hydrophobic monomer and a hydrophilic monomer in a solvent, the polymerization can be carried out in the presence of an oil-soluble polymerization initiator. The oil-soluble polymerization initiator can contain an oil-soluble organic peroxide, an oil-soluble azo compound, and the like, which will be described later. The amount of the oil-soluble polymerization initiator used when synthesizing the amphiphilic polymer is the sum of the hydrophobic monomers and hydrophilic monomers used to synthesize the amphiphilic polymer. It is preferably 0.01 to 3.0 parts by mass, more preferably 0.03 to 2.0 parts by mass, and 0.1 to 1.0 parts by mass with respect to 100 parts by mass. is more preferred.

Alkaline substances used for neutralization after synthesis of the crosslinkable polymer include, for example, ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethanolamine, diethanolamine, triethanolamine, dimethylaminoethanol, and the like. amines; and alkali metal hydroxides such as potassium hydroxide and sodium hydroxide; The alkaline substance may contain one of the above alone or two or more of them. The amount of the alkaline substance used is such that the pH of the aqueous solution of the amphipathic polymer is 5.0 to 9.0, more preferably 5.5 to 8.5, and still more preferably 6.0 to 8.0. can be changed as appropriate.

A chain transfer agent may be used in polymerizing the monomer components of the hydrophobic monomer and the hydrophilic monomer in the solvent. Chain transfer agents include, for example, octyl thioglycolate, methoxybutyl thioglycolate, octyl mercaptopropionate, methoxybutyl mercaptopropionate, mercaptans such as stearyl mercaptan and lauryl mercaptan, α-methylstyrene dimer, and the like. The chain transfer agent may contain one of the above alone or two or more.

The polymerization temperature for obtaining the amphiphilic polymer is preferably 40 to 100°C, more preferably 50 to 90°C, depending on the type of polymerization initiator. The polymerization time is preferably 1 to 24 hours, more preferably 3 to 12 hours.

The aqueous phase used for inversion emulsification may be a liquid medium similar to the aqueous dispersion medium described later, and is preferably at least deionized water. By inversion emulsification, an aqueous liquid of the amphipathic polymer is obtained. The aqueous liquid of the amphiphilic polymer may be an aqueous dispersion in which the crosslinkable polymer is dispersed, or an aqueous solution in which the crosslinkable polymer is dissolved. may be dispersed and the other part may be dissolved.

Manufacturing step 1 preferably includes removing the solvent after the inversion emulsification described above. The solvent can be removed by subjecting the liquid containing the amphiphilic polymer, solvent, and water to, for example, reduced pressure, heating, or both. The temperature at which the solvent is removed is preferably 40 to 90°C, more preferably 40 to 80°C, even more preferably 50 to 70°C. The reduced pressure condition is preferably -0.45 to 0.75 MPa.

(Manufacturing step 2: Preparation of mixed solution containing fluorine-containing (meth)acrylic monomer)
A mixture of fluorine-containing (meth)acrylic monomers is obtained by carrying out production step 2. That is, the production step 2 includes a step of mixing a monomer component containing at least a fluorine-containing (meth)acrylic monomer and a polymerization initiator in an aqueous dispersion medium to prepare a mixture of monomer components.

The mixture of fluorine-containing (meth)acrylic monomers contains an aqueous dispersion medium, which is a liquid medium containing at least water. The aqueous dispersion medium may be water alone or a combination of organic solvents that are miscible with water. The water is preferably deionized water (ion-exchanged water). Examples of organic solvents include, but are not limited to, methanol, ethanol, isopropanol, ethylcarbitol, N-methylpyrrolidone, and the like.

(Manufacturing step 3: Polymerization of fluorine-containing (meth)acrylic monomer)
A fluorine-containing aqueous resin particle dispersion is obtained by carrying out the production step 3. That is, the production step 3 includes a step of adding and mixing the liquid mixture to the aqueous solution of the amphipathic polymer, and then polymerizing the monomer components.

The fluorine-containing aqueous resin particle dispersion contains 30% by mass or more and 300% by mass or less of the amphiphilic polymer based on the total mass of the resin particles from the viewpoint of keeping the resin particles in a stable dispersed state.

In conducting soap-free microemulsion polymerization, polymerization initiators such as water-soluble polymerization initiators and oil-soluble polymerization initiators may be used. In this production method, from the viewpoint of polymerization stability, the soap-free microemulsion polymerization is preferably carried out in the presence of an oil-soluble polymerization initiator. As a result, radicals are generated from the oil-soluble polymerization initiator dissolved in the monomer droplets (oil-phase droplets of the monomer component containing the fluorine-containing (meth)acrylic monomer) dispersed in the aqueous solution of the amphipathic polymer. can be made The radicals can promote the polymerization of the monomer component, and a kind of suspension polymerization is carried out by generating radicals in the oil phase.

(Oil-soluble polymerization initiator)
Oil-soluble polymerization initiators include, for example, 4-dichlorobenzoyl peroxide, t-butyl peroxypivalate, benzoyl peroxide, o-methylbenzoyl peroxide, bis-3,5,5-trimethylhexanoyl peroxide, octa noyl peroxide, t-butylperoxy-2-ethylhexanoate, cyclohexanone peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, lauroyl peroxide, diisopropylbenzene hydroperoxide, t-butyl hydroperoxide, and t- Oil-soluble organic peroxides such as butyl peroxide, such as 2,2′-azobisisobutyronitrile, 2,2′-azobis(2,4-dimethylvaleronitrile), 2,2′-(2, 4-dimethyl-4-methoxyvaleronitrile) and other oil-soluble azo compounds. The oil-soluble polymerization initiator is preferably an oil-soluble azo compound. The oil-soluble polymerization initiator may contain one of the above alone or two or more of them.

The amount of the oil-soluble polymerization initiator to be used is preferably 0.01 to 3.0 parts by mass, preferably 0.03 to 2.0 parts by mass, based on 100 parts by mass of the monomer component used for synthesizing the resin particles. It is more preferably 0.1 to 1.0 parts by mass.

The method of adding the monomer components and the polymerization initiator to the aqueous liquid of the amphiphilic polymer is not particularly limited, and may be, for example, a batch addition method, a continuous addition method, or a multistage addition method. These addition methods may be used in combination as appropriate.

The polymerization temperature during soap-free microemulsion polymerization is preferably 40 to 100°C, more preferably 50 to 90°C, and further preferably 55 to 85°C, depending on the type of polymerization initiator. preferable. The polymerization time during soap-free microemulsion polymerization is preferably 1 to 24 hours, more preferably 3 to 12 hours, and even more preferably 5 to 10 hours.

(crosslinking agent)
The fluorine-containing aqueous resin particle dispersion of the present invention can further contain a cross-linking agent having two or more groups capable of reacting with the reactive groups of the protective layer made of an amphipathic polymer. By adding a cross-linking agent to the fluorine-containing aqueous resin particle dispersion, the protective layer of the amphipathic polymer can be cross-linked to form a three-dimensional network structure. As a result, the protective layer of the amphiphilic polymer can be cured, and a film formed from the fluorine-containing aqueous resin particle dispersion with improved mechanical properties and durability can be formed.

The cross-linking agent can be appropriately selected according to the type of reactive group of the protective layer of the amphipathic polymer. For example, when the reactive group is a carbonyl group, it is preferable to use a polyfunctional hydrazide compound or the like as a cross-linking agent. When the reactive group is a carboxy group, it is preferable to use polyfunctional epoxy compounds, polyfunctional carbodiimide compounds, melamine-based crosslinking agents such as methylolmelamine, polyfunctional oxazoline compounds, polyvalent metals, etc. as crosslinking agents. When the reactive group is a phosphate group or a phosphate ester group, it is preferable to use a compound having many hydroxyl groups as a cross-linking agent. When the reactive group is a hydroxyl group, it is preferable to use a polyfunctional isocyanate compound, its blocked isocyanate, an acid anhydride, etc. as a cross-linking agent. When the reactive group is a glycidyl group, it is preferable to use polyfunctional carboxy group-containing compounds, polyamines, acid anhydrides, etc. as cross-linking agents. When the reactive group is an isocyanate group or a blocked isocyanate group, it is preferable to use a polyol, polyamine, polycarboxylic acid compound or the like as a cross-linking agent. When the reactive group is an alkoxysilyl group, it is preferable to use a polyalkoxysilyl group compound or the like as a cross-linking agent. When the reactive group is a (meth)acryloyl group, it is preferable to use a polyunsaturated compound or the like as a cross-linking agent.

<Application of fluorine-containing aqueous resin particle dispersion>
The fluorine-containing aqueous resin particle dispersion of the present invention is used for waterproof coating of substrates. Since the fluorine-containing aqueous resin particle dispersion can form a film having excellent water resistance, it can be suitably used for film-forming materials such as paints, inks, adhesives, adhesives, and coating agents. When forming a coating using the fluorine-containing aqueous resin particle dispersion, the coating can be formed by applying the fluorine-containing aqueous resin particle dispersion to the base material on which the coating is to be formed and drying. Examples of coating methods include roll coating, bar coating, screen coating, die coating, spin coating, knife coating, blade coating, gravure coating, and spray coating. Substrates include, but are not limited to, various types of plastics, wood, glass, metal, paper, and the like.

<Production of Fluorine-Containing Aqueous Resin Particle Dispersion, etc.>
Table 1 shows raw material formulations for the production of the amphiphilic polymer aqueous solution. Table 2 shows raw material formulations and test results for producing fluorine-containing aqueous resin particle dispersions of Examples 1 to 6. Table 3 shows raw material formulations and test results for the production of fluorine-containing acrylic resin compositions of Comparative Examples 1-3.

(Production Example A-1 Production of Aqueous Liquid (A) of Amphiphilic Polymer)
Based on the raw material composition of Production Example A-1 in Table 1, 100.6 parts by mass of butyl acetate, butyl acrylate ( BA) 36.5 parts by mass, methyl methacrylate (MMA) 47.5 parts by mass, acrylic acid (AAc) 10 parts by mass, 2-hydroxyethyl acrylate (HEA) 1 part by mass, diacetone acrylamide (DAAM) 5 parts by mass, and 1 part by mass of N-dodecylmercaptan (L-SH) were charged, and the temperature was raised to 50° C. while stirring in a nitrogen atmosphere.

0.4 parts by mass of azobisisobutyronitrile (AIBN) was added into the separable flask and immediately heated to 85°C. After polymerization for 3 hours while maintaining the temperature in the separable flask at 85° C., a solution of 12 parts by mass of 25% aqueous ammonia and 40 parts by mass of deionized water (DIW) was added over 30 minutes. After stirring for 30 minutes, 240 parts by mass of deionized water (DIW) was added over 1 hour to reverse the continuous phase to the aqueous phase.

Next, butyl acetate is distilled off together with water under a reduced pressure of −0.45 to 0.75 MPa at an internal temperature of 50 to 70° C. in the separable flask to obtain an aqueous amphiphilic polymer solution (A-1). Obtained. The amphipathic polymer aqueous liquid (A-1) was a translucent liquid with a solid content of 30.0%. The average particle size of the amphipathic polymer was 18 nm.

(Production Example A-2 Production of Aqueous Liquid (A) of Amphiphilic Polymer)
Based on the raw material composition of Production Example A-2 in Table 1 and the production process similar to that of Production Example A-1, an aqueous amphiphilic polymer solution of Production Example A-2 was produced. The C6SFA monomer represents 2-(perfluorohexyl)ethyl acrylate.

(Example 1 Production of fluorine-containing aqueous resin particle dispersion)
Based on the raw material formulation of Example 1 in Table 2, 333.3 of amphiphilic polymer (A-1) was added to a four-necked separable flask equipped with a stirrer, thermometer, reflux condenser, and dropping funnel. Parts by weight (100.0 parts by weight of active ingredient) and 366.3 parts by weight of deionized water were charged. 80.0 parts by weight of 2-(perfluorohexyl)ethyl acrylate (C6SFA monomer), 20.0 parts by weight of methyl methacrylate (MMA), and 0.0 parts by weight of azobisisobutyronitrile (AIBN) were added while stirring under a nitrogen atmosphere. A monomer mixture of 4 parts by mass was added to the amphiphilic polymer (A-1) mixture over 30 minutes.

Subsequently, the internal temperature of the separable flask was raised to 70° C., and the polymerization reaction was carried out over 8 hours, and then cooled to room temperature to obtain a fluorine-containing aqueous resin particle dispersion. The solid content of the fluorine-containing aqueous resin particle dispersion was 25.0%. The average particle size of the fluorine-containing aqueous resin particle dispersion was 21 nm.

(Examples 2 to 6 Production of fluorine-containing aqueous resin particle dispersion)
Fluorine-containing aqueous resin particle dispersions of Examples 2 to 6 were produced based on the raw material formulations of Examples 2 to 6 in Table 2 and the same production process as in Example 1. Viscoat 3F represents 2,2,2-trifluoroethyl (meth)acrylate.

(Comparative Example 1 Production of fluorine-containing acrylic resin composition)
Based on the raw material formulation of Comparative Example 1 in Table 3, 229.4 parts by mass of deionized water and a reactive anionic emulsifier were added to a four-necked separable flask equipped with a stirrer, thermometer, reflux condenser, and dropping funnel. 0.4 parts by mass of a sulfonate salt of allyloxymethylalkyloxypolyoxyethylene (trade name "Aquaron KH-10", manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was charged as a solution, and the internal temperature was raised to 80 ° C. while stirring. let me

On the other hand, separately from the separable flask, 2-(perfluorohexyl) ethyl acrylate (C6SFA monomer) 40.0 parts by weight, methyl methacrylate (MMA) 33.0 parts by weight, butyl acrylate (BA) 25.0 parts by weight , and a monomer component of 2.0 parts by mass of acrylic acid (AAc), and a sulfonate salt of allyloxymethylalkyloxypolyoxyethylene as a reactive anionic emulsifier (trade name "Aquaron KH-10", Daiichi Kogyo Seiyaku ( 7.6 parts by mass (manufactured by Co., Ltd.) and 49.2 parts by mass of deionized water were emulsified with a homodisper to prepare a monomer emulsion.

Next, while maintaining the internal temperature in the separable flask at 80 ° C., 1 part of 10% by mass ammonium persulfate was added to the deionized water in the separable flask, and immediately the prepared monomer emulsification was performed. The liquid was uniformly dropped from the dropping funnel over 3 hours, and at the same time, 20 parts by mass of 1% by mass ammonium persulfate aqueous solution was uniformly dropped over 3 hours. After completion of dropping, the mixture was maintained at 80° C. for 3 hours, cooled to room temperature, and neutralized with 1.7 parts by mass of 25% aqueous ammonia to obtain a fluorine-containing acrylic resin composition. The solid content of the resulting fluorine-containing acrylic resin composition was 21.5%, lower than the theoretical value (25.0%), and a large amount of aggregates were formed during polymerization. The average particle size of the fluorine-containing acrylic resin composition was 151 nm.

(Comparative Example 2 Production of fluorine-containing acrylic resin composition)
Based on the raw material formulation of Comparative Example 2 in Table 3, the monomer components used in Comparative Example 1 were 20.0 parts by mass of 2-(perfluorohexyl)ethyl acrylate (C6SFA monomer), 38 parts by mass of methyl methacrylate (MMA). 0 parts by mass, 40.0 parts by mass of butyl acrylate (BA), and 2.0 parts by mass of acrylic acid (AAc) to obtain a fluorine-containing acrylic resin composition under the same conditions as in Comparative Example 1. . The solid content of the fluorine-containing acrylic resin composition was 24.0%, lower than the theoretical value, and aggregates were formed during polymerization. The average particle size of the fluorine-containing acrylic resin composition was 110 nm.

(Comparative Example 3 Production of fluorine-containing acrylic resin composition)
Based on the raw material formulation of Comparative Example 3 in Table 3, 229.4 parts by mass of deionized water and a reactive anionic emulsifier were added to a four-necked separable flask equipped with a stirrer, thermometer, reflux condenser, and dropping funnel. As a sulfonate salt of allyloxymethylalkyloxypolyoxyethylene (trade name "Aquaron KH-10", manufactured by Daiichi Kogyo Seiyaku Co., Ltd.; the same applies to the following reactive anionic emulsifiers.) 0.4 parts by mass, The liquid temperature was raised to 80° C. while stirring.

On the other hand, separately from the flask, a monomer component (total of 50.0 parts by mass ), 3.6 parts by mass of a reactive anionic emulsifier, and 24.7 parts by mass of deionized water were emulsified with a homodisper to prepare a first-stage monomer emulsion.

Next, while maintaining the liquid temperature in the flask at 80 ° C., 1.0 parts by mass of a 10% by mass ammonium persulfate aqueous solution was added to the flask, and immediately, the prepared first-stage monomer emulsion was added. was uniformly dropped from the dropping funnel over 1 hour, and at the same time, 10.0 parts by mass of a 1% by mass ammonium persulfate aqueous solution was uniformly dropped over 1 hour. After further polymerization for 1 hour, a first-stage emulsion polymerization liquid was obtained.

Subsequently, the previously prepared second-stage monomer emulsion and 10 parts by mass of a 1% by mass ammonium persulfate aqueous solution were simultaneously added dropwise to the first-stage emulsion polymerization liquid over a period of 1 hour. The second-stage monomer emulsion contains 20.0 parts by weight of methyl methacrylate (MMA), 25.0 parts by weight of butyl acrylate (BA), 2.0 parts by weight of acrylic acid (AAc), and 2-hydroxyethyl acrylate. (HEA) 0.5 parts by mass and diacetone acrylamide (DAAM) 2.5 parts by mass (total 50.0 parts by mass), reactive anionic emulsifier 4 parts by mass, and deionized water 24. A monomer emulsion containing 5 parts by mass was used. After the completion of dropping, the polymer solution was maintained at 80° C. for 3 hours, then cooled to room temperature (about 25° C.), and neutralized by adding 1.7 parts by mass of 25% by mass aqueous ammonia to the polymer solution. A fluorine-containing acrylic resin composition No. 3 was obtained. The solid content of the fluorine-containing acrylic resin composition was 23.8%, lower than the theoretical value (25.0%), and a large amount of aggregates were formed during polymerization. The average particle size of the fluorine-containing acrylic resin composition was 144 nm.

<Test method>
Using the fluorine-containing aqueous resin particle dispersions of Examples 1 to 6 and the fluorine-containing acrylic resin compositions of Comparative Examples 1 to 3, performance evaluation was performed by performing the tests of Test Examples 1 to 4 below. .

(Test Example 1 Measurement of average particle size)
The average particle size (d50) of the fluorine-containing aqueous resin particle dispersion and the average particle size (d50) of the fluorine-containing acrylic resin composition were measured using a particle size distribution analyzer (manufactured by Otsuka Electronics Co., Ltd., trade name "Concentrated particle size It was measured using an analyzer FPAR-1000").

(Test Example 2 Evaluation of manufacturing stability)
After the production of the fluorine-containing aqueous resin particle dispersion and the fluorine-containing acrylic resin composition, the formation of aggregates was visually observed. Based on the following evaluation criteria, production stability during production of the fluorine-containing aqueous resin particle dispersion and the fluorine-containing acrylic resin composition was evaluated.
(Evaluation criteria)
◯: Almost no aggregates are observed.
Δ: A small amount of aggregates are produced.
x: A large amount of aggregates are generated.

(Test Example 3 Evaluation of storage stability)
Each of the fluorine-containing aqueous resin particle dispersion and the fluorine-containing acrylic resin composition was placed in a glass vial, and allowed to stand at 40°C. After one week of standing, the state of the contents in the vial (that is, the presence or absence of sediment) was visually confirmed. Based on the following evaluation criteria, storage stability during production of the fluorine-containing aqueous resin particle dispersion and the fluorine-containing acrylic resin composition was evaluated.
(Evaluation criteria)
O: No sediment was observed.
x: A sediment is observed.

(Test Example 4 Measurement of water contact angle)
A mixture obtained by adding 1.25 g of a 5% aqueous dihydrazide adipic acid solution to 20 g of a fluorine-containing aqueous resin particle dispersion or a fluorine-containing acrylic resin composition was applied onto a glass plate using an applicator to a thickness of 100 μm, A test plate was obtained by drying at 60° C. for 20 minutes. A water droplet of 2 μL is dropped on the surface of the obtained test plate, and a fully automatic contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., device name: DMo-701) is used to measure the water contact angle by the liquid method. bottom.

<Test results>
The test results of Examples 1-6 and Comparative Examples 1-3 will be described with reference to Tables 2-3. First, Examples 1 to 6 had excellent performance in all evaluation items (average particle size, production stability, storage stability, water contact angle). On the other hand, Comparative Examples 1 to 3 satisfied only some of the evaluation items. A comparison between Example 1 and Comparative Examples 1 to 3 will be described below.

(Comparison between Example 1 and Comparative Example 1)
The production stability and storage stability of Example 1 were improved over those of Comparative Example 1 (when no amphipathic polymer was included). In Comparative Example 1, a monomer emulsion containing a reactive anionic emulsifier emulsified by homodisper is polymerized. Therefore, the average particle size (151 nm) of the fluorine-containing acrylic resin composition of Comparative Example 1 is larger than the average particle size (20 to 100 nm) specified in the present invention. Particles with a larger average particle size are more likely to settle in an aqueous dispersion medium, so the production stability and storage stability of Comparative Example 1 are degraded. On the other hand, in Example 1, polymerization (soap-free microemulsion polymerization in the present specification) was performed after adding and mixing a monomer mixture to an aqueous solution of an amphiphilic polymer as a substitute for an emulsifier or the like. Therefore, the average particle size of the fluorine-containing aqueous resin particle dispersion can be reduced. In addition, since the average particle size of the fluorine-containing aqueous resin particle dispersion of Example 1 is very small, sedimentation of the resin particles in the aqueous dispersion medium is suppressed. Therefore, the production stability and storage stability of Example 1 are excellent.

(Comparison between Example 1 and Comparative Example 2)
The production stability and storage stability of Example 1 were improved over those of Comparative Example 2 (when a small amount of fluorine-containing (meth)acrylic monomer was included). In Comparative Example 2, a fluorine-containing acrylic monomer containing a fluorine-containing (meth)acrylic monomer in a smaller amount than the amount specified in the present invention (40% by mass or more and 100% by mass or less with respect to the total mass of the resin particles) Although it is contained in the resin composition, the average particle size of the fluorine-containing acrylic resin composition cannot be reduced. Therefore, the manufacturing stability and storage stability of Comparative Example 2 are degraded. Since the description of the first embodiment is the same as the above, detailed description is omitted.

(Comparison between Example 1 and Comparative Example 3)
The production stability and storage stability of Example 1 were improved over those of Comparative Example 3 (when performing two-step polymerization). In Comparative Example 3, after polymerizing a monomer emulsion containing a highly hydrophobic fluorine-containing (meth)acrylic monomer in the presence of an emulsifier, a monomer emulsion containing other monomers as structural units was prepared. is added and mixed, and polymerized further. In Comparative Example 3, two-step polymerization was carried out in the same manner as in Example 1, but the average particle size of the fluorine-containing acrylic resin composition could not be reduced. Therefore, the production stability and storage stability of Comparative Example 3 are degraded. Since the description of the first embodiment is the same as the above, detailed description is omitted.

As described above, the fluorine-containing aqueous resin particle dispersion of the present invention has a remarkable effect of being excellent in long-term storage stability. Further, the refractive index of fluororesin is generally lower than that of acrylic resin. For this reason, when a composite material of fluororesin and acrylic resin is formed, the composite material may have reduced transparency. However, since the average particle size of the fluorine-containing aqueous resin particle dispersion of the present invention is very small, visible light can pass through the composite material (that is, the film formed from the fluorine-containing aqueous resin particle dispersion). Thus, the fluorine-containing aqueous resin particle dispersion of the present invention also has the effect of enhancing the transparency of the composite material (the above-described film).

The invention is not limited to the above embodiments, and various modifications and changes are possible within the scope of the invention.

Claims (7)

A fluorine-containing aqueous resin particle dispersion containing resin particles,
Containing at least a fluorine-containing (meth)acrylic monomer as a structural unit covered by a protective layer formed of an amphiphilic polymer comprising a copolymer of a hydrophobic monomer and a hydrophilic monomer containing resin particles,
The fluorine-containing aqueous resin particle dispersion has an average particle size of 20 to 60 nm,
Here, the average particle size of the fluorine-containing aqueous resin particle dispersion is measured using a dynamic light scattering method,
The amphiphilic polymer contains 5% by mass or more of structural units derived from a carboxy group-containing polymerizable monomer having a carboxy group as the hydrophilic monomer, relative to the total mass of the amphiphilic polymer. , containing at 20% by mass or less,
The hydrophobic monomer includes methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, containing at least one of styrene and 2-(perfluorohexyl)ethyl acrylate (C6SFA) ;
The hydrophilic monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (meth)acrylic acid, (meth)acrylonitrile, and (meth)acrylamide. , including at least one of diacetone acrylamide,
The fluorine-containing aqueous resin particle dispersion does not contain an emulsifier, a surfactant, or a dispersant.
Fluorine-containing aqueous resin particle dispersion. The resin particles contain the fluorine-containing (meth)acrylic monomer as a structural unit in an amount of 40% by mass or more and 100% by mass or less with respect to the total mass of the resin particles.
2. The fluorine-containing aqueous resin particle dispersion according to claim 1. The fluorine-containing aqueous resin particle dispersion contains the amphipathic polymer in an amount of 30% by mass or more and 300% by mass or less with respect to the total mass of the resin particles.
2. The fluorine-containing aqueous resin particle dispersion according to claim 1. The amphiphilic polymer comprises a structural unit derived from a monomer having cross-linking reactivity,
2. The fluorine-containing aqueous resin particle dispersion according to claim 1. The monomer having cross-linking reactivity includes diacetone acrylamide,
5. The fluorine-containing aqueous resin particle dispersion according to claim 4 . for water-resistant coatings,
The fluorine-containing aqueous resin particle dispersion according to any one of claims 1 to 5 . After synthesizing an amphiphilic polymer by solution polymerization of a hydrophobic monomer and a hydrophilic monomer in a solvent, after neutralization with an alkaline substance, inversion emulsification is carried out in an aqueous phase to obtain an aqueous solution of the amphiphilic polymer. a step of preparing a liquid;
A step of mixing a monomer component containing at least a fluorine-containing (meth)acrylic monomer and a polymerization initiator in an aqueous dispersion medium to prepare a mixture of the monomer components;
After adding and mixing the mixed liquid to the aqueous liquid of the amphiphilic polymer, the step of polymerizing the monomer component,
The amphiphilic polymer contains 5% by mass or more of structural units derived from a carboxy group-containing polymerizable monomer having a carboxy group as the hydrophilic monomer, relative to the total mass of the amphiphilic polymer. , containing at 20% by mass or less,
The hydrophobic monomer includes methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, containing at least one of styrene and 2-(perfluorohexyl)ethyl acrylate (C6SFA) ;
The hydrophilic monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (meth)acrylic acid, (meth)acrylonitrile, and (meth)acrylamide. , including at least one of diacetone acrylamide,
A method for producing a fluorine-containing aqueous resin particle dispersion.