JP6917764B2 - Polymer particle aqueous dispersion and coating film - Google Patents

Description

The present invention relates to an aqueous dispersion of polymer particles and a coating film.

In recent years, people's awareness of the environment has increased due to the global warming phenomenon, and new energy systems that do not generate greenhouse gases such as carbon dioxide are attracting attention. Among them, solar cells are attracting attention because of their excellent safety and ease of handling. In many solar cells, a base material having an uneven structure on the surface, for example, a textured glass base material, is used as a protective cover from the viewpoint of antiglare property, light transmission, and the like.

A method of forming a coating film on the surface of the solar cell cover glass is known in order to increase the output of the solar cell or maintain it for a long period of time.

For example, Patent Document 1 discloses a coating film having antireflection and antifouling properties, which is formed by applying a coating material composed of an aqueous dispersion of polymer particles and silica particles.

International Publication No. 2010/10146 Pamphlet

However, the coating film described in Patent Document 1 in which the paint is applied to the surface of a base material having an uneven structure on the surface has a film thickness after drying due to the accumulation of the paint liquid in the concave portion of the surface. However, the concave portion of the base material is thick and the convex portion of the base material is thin, resulting in uneven film thickness.
As one of the methods for reducing the film thickness unevenness, there is a method of increasing the amount of volatile solvent in the paint to increase the drying rate. However, many polymer particle aqueous dispersions are unstable to volatile solvents, and there is a problem that the optical properties of the coating film are deteriorated.

Therefore, an object of the present invention is to provide a polymer particle aqueous dispersion capable of exhibiting excellent optical properties when forming a coating film.

As a result of diligent studies on the problems of the prior art, the present inventions are polymer particle aqueous dispersions containing 50 to 95% by mass of a water-soluble solvent having a boiling point of less than 100 ° C., and the polymer particle aqueous dispersion. The volume average particle size of the solid content particles contained in the aqueous dispersion of polymer particles when the water-soluble solvent concentration in the body is diluted with water to 10% by mass or less is larger than the volume average particle size before water dilution. We have found that an aqueous dispersion of polymer particles having a content of 50 to 200% can exhibit excellent optical properties when forming a coating film, and have completed the present invention.

That is, various aspects of the present invention are as follows.
[1]
A polymer particle aqueous dispersion containing 50 to 95% by mass of a water-soluble solvent having a boiling point of less than 100 ° C., diluted with water until the concentration of the water-soluble solvent in the polymer particle aqueous dispersion becomes 10% by mass or less. A polymer particle aqueous dispersion in which the volume average particle diameter of the solid content particles contained in the polymer particle aqueous dispersion is 50 to 200% of the volume average particle diameter before water dilution.

[2]
The coating film of the aqueous dispersion of polymer particles according to the above [1], which is formed on the surface of a base material.
[3]
The coating film according to the above [2], which is formed on the surface of a cover glass for a solar cell.

According to the present invention, a polymer particle aqueous dispersion capable of forming a coating film having excellent optical properties can be obtained.

Hereinafter, embodiments for carrying out the present invention (hereinafter, abbreviated as “embodiments”) will be described in detail.
The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be appropriately modified and implemented within the scope of the gist thereof.
In addition, in this specification, "(meth) acrylate" means both acrylate and the corresponding methacrylate. Further, "(meth) acrylic acid" means both acrylic acid and the corresponding methacrylic acid.

<Polymer particle aqueous dispersion>
The polymer particle aqueous dispersion of the present invention is a polymer particle aqueous dispersion containing 50 to 95% by mass of a water-soluble solvent having a boiling point (under atmospheric pressure) of less than 100 ° C. The volume average particle size of the solid content particles contained in the aqueous dispersion of polymer particles when the concentration of the water-soluble solvent in the solvent is diluted with water to 10% by mass or less is larger than the volume average particle size before water dilution. It is 50 to 200%.
Preferably, the volume average particle size of the solid content particles contained in the aqueous dispersion of the polymer particles when the concentration of the water-soluble solvent in the aqueous dispersion of the polymer particles is diluted with water to 10% by mass or less is diluted with water. It may be 60 to 180%, more preferably 60 to 150% of the previous volume average particle size.
When the rate of change in the volume average particle size due to water dilution of the polymer particle aqueous dispersion is within the above range, a coating film having excellent optical properties can be formed. One of the indicators of "excellent optical properties" here is typically haze, for example, haze measured by the method specified in JIS K7361-1 is 5% or less, preferably 4% or less. It means that it is more preferably 3% or less, further preferably 2% or less, and most preferably 1% or less.

Examples of the water-soluble solvent having a boiling point of less than 100 ° C. include, but are not limited to, alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol and t-butyl alcohol, acetone, tetrahydrofuran, acetonitrile and the like. Can be mentioned.

The water-soluble solvent in the aqueous dispersion of the polymer particles is 50 to 95% by mass, preferably 60 to 95% by mass, and more preferably 70 to 95% by mass. By applying a polymer particle aqueous dispersion containing a water-soluble solvent in the above range to a substrate, a coating film with reduced film thickness unevenness can be obtained.

The polymer particle aqueous dispersion has a volume average particle diameter of solid content particles contained in the polymer particle aqueous dispersion when the concentration of the water-soluble solvent is diluted with water from 50 to 95% by mass to 10% by weight. It is 50 to 200%, preferably 60 to 150%, and more preferably 80 to 130% with respect to the volume average particle size before dilution with water. By applying a polymer particle aqueous dispersion showing a change in volume average particle size in the above range to a substrate, a coating film having a low coating film haze and good optical characteristics can be obtained. A polymer particle aqueous dispersion having a volume average particle size change in the above range due to water dilution can be obtained by suppressing the bleeding component of the polymer by a water-soluble solvent depending on the monomer type and ratio of the polymer and the degree of cross-linking. ..
In the present specification, the aqueous dilution of the polymer particle aqueous dispersion can be usually carried out by adding distilled water to the polymer particle aqueous dispersion stirred with a stirrer to adjust the concentration. Further, in the present specification, the measurement of the volume average particle size can usually be performed by using a dynamic light scattering method.

The polymer constituting the polymer particle aqueous dispersion is not limited to the following, and is, for example, a polyurethane-based, polyester-based, poly (meth) acrylate-based, poly (meth) acrylate-silicone-based copolymer, and the like. Examples thereof include polyvinyl acetate-based, polybutadiene-based, polyvinyl chloride-based, chlorinated polypropylene-based, polyethylene-based, polystyrene-based, and polystyrene- (meth) acrylate-based copolymers.
The volume average particle size of the polymer constituting the polymer particle aqueous dispersion is not particularly limited, but is usually 10 nm to 500 nm, and more typically 20 nm to 100 nm.

In one embodiment, the aqueous dispersion of polymer particles is preferably obtained by polymerizing a hydrolyzable silicon compound and a vinyl compound from the viewpoint of the optical properties of the coating film.

The hydrolyzable silicon compound is not particularly limited, and examples thereof include a compound represented by the following formula, a condensation product thereof, and a silane coupling agent.
Formula: SiW _{x Ry}
Here, in the formula, W is an alkoxy group having 1 to 20 carbon atoms, a hydroxyl group, an acetoxy group having 1 to 20 carbon atoms, a halogen atom, a hydrogen atom, an oxime group having 1 to 20 carbon atoms, an enoxy group, an aminoxic group and an amide. Represents at least one group selected from the group consisting of groups. R is a linear or branched alkyl group having 1 to 30 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, and an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms or 1 carbon group. Represents at least one hydrocarbon group selected from the group consisting of ~ 20 alkoxy groups or aryl groups having 6 to 20 carbon atoms substituted with halogen atoms. x is an integer of 1 or more and 4 or less, and y is an integer of 0 or more and 3 or less. Further, x + y = 4.

The silane coupling agent means a silane derivative in which a functional group reactive with an organic substance such as a vinyl polymerizable group, an epoxy group, an amino group, a methacryl group, a mercapto group and an isocyanate group is present in the molecule.

The hydrolyzable silicon compound constituting the aqueous dispersion of polymer particles is not limited to the following, and is, for example, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, and tetra. Tetraalkoxysilanes such as -n-butoxysilane; methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane , Isopropyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, n-pentyltrimethoxysilane, n-hexyltrimethoxysilane, n-heptiltiltrimethoxysilane, n-octyltrimethoxysilane, vinyltri Methoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3 , 3,3-Trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-hydroxyethyltrimethoxysilane, 2, -Hydroxyethyltriethoxysilane, 2-hydroxypropyltrimethoxysilane, 2-hydroxypropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-hydroxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercapto Propyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-) Epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3- (meth) acrylicoxypropyltrimethoxysilane, 3- (meth) acrylicoxypropyltriethoxysilane, 3-( Meta) acryloyloxypropyltri n-propoxysilane, 3- (meth) acryloyloxypropyltriisopropoxysi Trialkoxysilanes such as orchids, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane; dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, di-n-propyldimethoxysilane, Di-n-propyldiethoxysilane, diisopropyldimethoxysilane, diisopropyldiethoxysilane, di-n-butyldimethoxysilane, di-n-butyldiethoxysilane, di-n-pentyldimethoxysilane, di-n-pentyldiethoxy Silane, di-n-hexyldimethoxysilane, di-n-hexyldiethoxysilane, di-n-heptyldimethoxysilane, di-n-heptyldiethoxysilane, di-n-octyldimethoxysilane, di-n-octyldi Dialkoxysilanes such as ethoxysilane, di-n-cyclohexyldimethoxysilane, di-n-cyclohexyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, 3- (meth) acryloyloxypropylmethyldimethoxysilane; trimethylmethoxysilane , Monoalkoxysilanes such as trimethylethoxysilane.

As the above-mentioned hydrolyzable silicon compound, only one kind may be used alone, or two or more kinds may be mixed and used.

The hydrolyzable silicon compound may include a silane coupling agent having a thiol group or a hydrolyzable silicon compound having a vinyl polymerizable group.

The silane coupling agent having a thiol group is not particularly limited, and examples thereof include 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane.

The hydrolyzable silicon compound having a vinyl polymerizable group is not particularly limited, and for example, 3- (meth) acrylicoxypropyltrimethoxysilane, 3- (meth) acrylicoxypropyltriethoxysilane, 3- (meth) acryloyl. Oxypropylmethyldimethoxysilane, 3- (meth) acryloyloxypropyltri n-propoxysilane, 3- (meth) acryloyloxypropyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, 2- Examples thereof include a silane coupling agent having a vinyl polymerizable group such as trimethoxysilylethyl vinyl ether.

These silane coupling agents can form a chemical bond by copolymerization with a vinyl monomer described later or a chain transfer reaction. Therefore, when a silane coupling agent having a vinyl polymerizable group or a thiol group is mixed or compounded with the above-mentioned hydrolyzable silicon compound, the polymerization product of the hydrolyzable silicon compound and the vinyl compound described later are used. The polymerization product can be compounded by a chemical bond.

Examples of the "vinyl polymerizable group" in the hydrolyzable silicon compound having a vinyl polymerizable group include a vinyl group and an allyl group. Non-limiting specific examples include 3- (meth) acrylic oxypropyl groups.

The hydrolyzable silicon compound may contain a cyclic siloxane oligomer. Examples of the cyclic siloxane oligomer include compounds represented by the following formulas.
Formula: (R _{'2 SiO) m}
Here, in the formula, R'is a hydrogen atom, a linear or branched alkyl group having 1 to 30 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, and an unsubstituted or branched alkyl group having 5 to 20 carbon atoms. At least one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms substituted with a halogen atom is shown. m is an integer and 2 ≦ m ≦ 20.
Of these, cyclic dimethylsiloxane oligomers such as octamethylcyclotetrasiloxane are preferable from the viewpoint of reactivity and the like.

The mass ratio of the hydrolyzed condensate of the hydrolyzable silicon compound (for example, the hydrolyzed condensate of tetraalkoxysilanes) containing 4 or more hydrolyzable functional groups contained in the polymer particle aqueous dispersion is heavy. It is preferably 20% or more and 50% or less, and more preferably 25% or more and 40% or less, based on the solid content of the entire aqueous dispersion of the coalesced particles.
Further, it is more preferable that the hydrolyzable silicon compound containing four or more hydrolyzable functional groups such as a hydrolyzable condensate of the tetraalkoxysilanes is present in the outermost layer of the polymer particles. The presence of the hydrolyzed condensate in the outermost layer tends to improve the stability of the polymer particles to the water-soluble solvent.

The vinyl compound (excluding the above-mentioned hydrolyzable silicon compound having a vinyl polymerizable group) for polymerizing with the hydrolyzable silicon compound is not limited to the following, but for example, (meth) acrylamide, ( Meta) Acrylic acid esters, aromatic vinyl compounds, vinyl cyanide compounds; compounds containing functional groups such as carboxyl group-containing vinyl compounds, hydroxyl group-containing vinyl compounds, epoxy group-containing vinyl compounds, and carbonyl group-containing vinyl compounds can be mentioned. .. Among them, a vinyl compound having a secondary amide group and / or a tertiary amide group is preferable because the hydrogen bond property with a metal oxide such as silica used in the coating composition tends to be strengthened.

Examples of the carboxyl group-containing vinyl compound are not particularly limited, but various unsaturated carboxylic acids such as (meth) acrylic acid, 2-carboxyethyl (meth) acrylate, crotonic acid, itaconic acid, maleic acid or fumaric acid. With unsaturated dicarboxylic acids such as monomethyl itaconate, mono-n-butyl itaconate, monomethyl maleate, mono-n-butyl maleate, monomethyl fumarate, mono-n-butyl fumarate and saturated monovalent alcohols. Monoesters (half esters); monovinyl esters of various saturated dicarboxylic acids such as monovinyl adipate or monovinyl succinate; various monovinyl esters such as succinic anhydride, glutaric anhydride, phthalic anhydride or trimellitic anhydride. Addition reaction product of the above-mentioned unsaturated polycarboxylic acid anhydrides and the above-mentioned various hydroxyl group-containing vinyl-based monomers; obtained by the addition reaction of the above-mentioned various carboxyl group-containing monomers and lactones. Examples thereof include monomers.

Examples of the hydroxyl group-containing vinyl compound are not particularly limited, but various hydroxyalkyl (meth) such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate or 4-hydroxybutyl (meth) acrylate. Acrylates; Various hydroxyl group-containing vinyl ethers such as 2-hydroxyethyl vinyl ether or 4-hydroxybutyl vinyl ether; Various hydroxyl group-containing allyl ethers such as 2-hydroxyethyl allyl ether; Various polys represented by polyethylene glycol. Monoesters of polyoxyalkylene glycols obtained from ether polyols and various unsaturated carboxylic acids typified by (meth) acrylic acid; the various hydroxyl group-containing monomers described above and ε-caprolactone typified. Additives with various lactones; Additives with various epoxy group-containing unsaturated monomers represented by glycidyl (meth) acrylate and various acids represented by acetic acid; represented by (meth) acrylic acid Examples thereof include additions of various unsaturated carboxylic acids and various monoepoxide compounds other than epoxide of α-olefin represented by “Cardura E” (trade name manufactured by Shell Co., Ltd. of the Netherlands).

As the above-mentioned vinyl compound, only one kind may be used alone, or two or more kinds may be mixed and used.

The above formula: formula: of the vinyl compound (b1) and the hydrolyzable silicon compound in the polymer particle aqueous dispersion when the hydrolyzable condensate (b2) of the hydrolyzable silicon compound represented by _{SiW x} R _{y is used.} The mass ratio (b1) / (b2) of the hydrolyzed condensate (b2) is preferably 1/100 to 1/1, more preferably 1/50 to 1/2, and even more preferably 1/20 to 1/4. .. Within the above range, the stability of the polymer particles with respect to a water-soluble solvent tends to improve.

An emulsifier may be used together with water in the synthesis of the polymer particles.
The emulsifier includes, but is not limited to, alkylbenzene sulfonic acid, alkyl sulfonic acid, alkyl sulfosuccinic acid, polyoxyethylene alkyl sulfate, polyoxyethylene alkyl aryl sulfate, polyoxyethylene distyrylphenyl ether sulfonic acid, and the like. Acid emulsifiers; alkali metal (Li, Na, K, etc.) salts of acidic emulsifiers, ammonium salts of acidic emulsifiers, anionic surfactants such as fatty acid soaps; alkyltrimethylammonium bromide, alkylpyridinium bromide, imidazolinium laurate, etc. Tertiary ammonium salt, pyridinium salt, imidazolinium salt type cationic surfactant; polyoxyethylene alkylaryl ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene oxypropylene block copolymer, polyoxyethylene distyrylphenyl ether Examples thereof include nonionic surfactants such as, and reactive emulsifiers having a radically polymerizable double bond.

The above-mentioned emulsifier may be used alone or in combination of two or more.

The reactive emulsifier having a radically polymerizable double bond is not particularly limited, but is limited to a vinyl monomer having a sulfonic acid group or a sulfonate group, a vinyl monomer having a sulfate ester group, and an alkali metal salt thereof. Examples thereof include a vinyl monomer having a nonionic group such as an ammonium salt and polyoxyethylene, and a vinyl monomer having a quaternary ammonium salt.

The vinyl monomer having a sulfonic acid group or a sulfonate group is not particularly limited, but is, for example, a substituent having a radically polymerizable double bond and a substituent such as an ammonium salt, a sodium salt or a potassium salt of the sulfonic acid group. Consists of an alkyl group having 1 to 20 carbon atoms, an alkyl ether group having 2 to 4 carbon atoms, a polyalkyl ether group having 2 to 4 carbon atoms, a phenyl group, a naphthyl group, and a succinic acid group partially substituted with. Compounds having a substituent selected from the group; examples thereof include vinyl sulfonate compounds having a vinyl group to which a substituent such as an ammonium salt, a sodium salt or a potassium salt of a sulfonic acid group is bonded.

The vinyl monomer having a sulfate ester group is not particularly limited, but is partially limited by, for example, having a radically polymerizable double bond and partially due to a substituent such as an ammonium salt, a sodium salt or a potassium salt of the sulfate ester group. Substituent selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkyl ether group having 2 to 4 carbon atoms, a polyalkyl ether group having 2 to 4 carbon atoms, a phenyl group, and a naphthyl group substituted with Examples thereof include compounds having.

The compound having a succinic acid group partially substituted with a substituent such as an ammonium salt, a sodium salt or a potassium salt of a sulfonic acid group is not particularly limited, and examples thereof include allyl sulfosuccinate. More specifically, for example, Eleminor JS-2 (manufactured by Sanyo Chemical Industries, Ltd., trade name), Latemul S-120, S-180A or S-180 (manufactured by Kao Corporation, trade name) and the like can be mentioned.

As a compound having an alkyl ether group having 2 to 4 carbon atoms or a polyalkyl ether group having 2 to 4 carbon atoms, which is partially substituted with a substituent such as an ammonium salt, a sodium salt or a potassium salt of a sulfonic acid group. Although not particularly limited, for example, Aqualon HS-10 or KH-1025 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name), Adecaria Soap SE-1025N or SR-1025 (manufactured by Asahi Denka Kogyo Co., Ltd., trade name) and the like can be mentioned. Be done.

The vinyl monomer having a nonionic group is not particularly limited, and is, for example, α- [1-[(allyloxy) methyl] -2- (nonylphenoxy) ethyl] -ω-hydroxypolyoxyethylene (trade name: Adecaria). Thorpe NE-20, NE-30, NE-40, etc., manufactured by Asahi Denka Kogyo Co., Ltd.), Polyoxyethylene alkyl propenylphenyl ether (trade names: Aqualon RN-10, RN-20, RN-30, RN-50, etc.) (Made by Daiichi Pharmaceutical Co., Ltd.).

From the viewpoint of polymerization stability, the amount of the emulsifier used in the synthesis of polymer particles is preferably 10 parts by mass or less, more preferably 0.001 parts, based on 100 parts by mass of the total of the hydrolyzable silicon compound and the vinyl compound. ~ 5 parts by mass.

In the synthesis of the polymer particle aqueous dispersion, it is preferable to polymerize the hydrolyzable silicon compound and the vinyl compound in the presence of a polymerization catalyst.

The polymerization catalyst of the hydrolyzable silicon compound can be appropriately selected depending on the components used for the polymerization and the like. Such polymerization catalysts are not limited to the following, but are, for example, hydrogen halides such as hydrochloric acid and fluoric acid, and carboxylic acids such as acetic acid, trichloroacetic acid, trifluoroacetic acid and lactic acid; sulfuric acid, p-. Sulfonic acids such as toluene sulfonic acid; acidic emulsifiers such as alkylbenzene sulfonic acid, alkyl sulfonic acid, alkyl sulfosuccinic acid, polyoxyethylene alkyl sulfuric acid, polyoxyethylene alkylaryl sulfuric acid, polyoxyethylene distyrylphenyl ether sulfonic acid; acidic or Weakly acidic inorganic salts, acidic compounds such as phthalic acid, phosphoric acid and sulfuric acid; sodium hydroxide, potassium hydroxide, sodium methylate, sodium acetate, tetramethylammonium chloride, tetramethylammonium hydroxide, tributylamine, diah Basic compounds such as zabicycloundecene, ethylenediamine, diethylenetriamine, ethanolamines, γ-aminopropyltrimethoxysilane, γ- (2-aminoethyl) -aminopropyltrimethoxysilane; dibutyltin octylate, dibutyltin dilaurate Examples of tin compounds such as.
Among these, acidic emulsifiers are preferable, and alkylbenzene sulfonic acid having 5 to 30 carbon atoms is more preferable, from the viewpoint of having an action as an emulsifier as well as a polymerization catalyst.

As the polymerization catalyst of the vinyl compound, a radical polymerization catalyst that undergoes radical decomposition by heat or a reducing substance to cause addition polymerization of the vinyl compound is preferable.
Such polymerization catalysts are not limited to the following, and include, for example, potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, t-butylhydroperoxide, t-butylperoxybenzoate, 2 , 2-Azobisisobutyronitrile, 2,2-azobis (2-diaminopropane) hydrogen peroxide, 2,2-azobis (2,4-dimethylvaleronitrile).

The amount of the vinyl compound polymerization catalyst used is preferably 0.001 to 5 parts by mass with respect to 100 parts by mass of the total vinyl compound. If it is desired to accelerate the polymerization rate and polymerize at a low temperature of 70 ° C. or lower, it is advantageous to use a reducing agent such as sodium bisulfite, ferrous chloride, ascorbic acid salt, or longalite in combination with a radical polymerization catalyst. be.

The polymerization of the hydrolyzable silicon compound and the polymerization of the vinyl compound can be carried out separately, but it is preferable to carry out the polymerization at the same time because a micro-organic-inorganic composite by hydrogen bonds or the like can be achieved.

As a method for obtaining an aqueous dispersion of polymer particles, so-called emulsion polymerization in which a hydrolyzable silicon compound and a vinyl compound are polymerized in the presence of an amount of water sufficient for an emulsifier to form micelles is suitable. As a method of emulsion polymerization, for example, a hydrolyzable silicon compound and a vinyl compound, and if necessary, an emulsifier as it is or in an emulsified state are collectively or divided, or continuously added dropwise into a reaction vessel. Examples thereof include a method of polymerizing at a reaction temperature of about 30 to 150 ° C. in the presence of a polymerization catalyst, preferably under a pressure from atmospheric pressure to 10 MPa if necessary. However, if necessary, polymerization may be carried out at a pressure higher than this or under temperature conditions lower than this.

From the viewpoint of polymerization stability, the hydrolyzable silicon compound, vinyl compound and water are blended so that the total solid content mass is in the range of 0.1 to 70% by mass, preferably 1 to 55% by mass. , And preferably each component of the emulsifier. The total solid content mass (mass%) can be determined based on the following formula by determining the dry mass of the aqueous dispersion of polymer particles placed in an oven heated to 100 ° C. for 2 hours and dried.
Total solid content mass (mass%) = dry mass / mass of polymer particle aqueous dispersion × 100

When carrying out emulsion polymerization, it is preferable to use a seed polymerization method from the viewpoint of appropriately growing or controlling the particle size of the obtained polymer particles. The seed polymerization method is a method in which emulsion particles (seed particles) are present in the aqueous phase in advance and polymerized. The pH in the polymerization system when the seed polymerization method is carried out is preferably 1.0 to 10.0, more preferably 1.0 to 6.0. The pH can be adjusted with a pH buffer such as disodium phosphate, borax, sodium bicarbonate, ammonia and the like.

As a method for obtaining an aqueous dispersion of polymer particles, the hydrolyzable silicon compound and vinyl compound are polymerized in the presence of an emulsifying agent and water necessary for polymerizing the hydrolyzable silicon compound, and then in the presence of a solvent, if necessary. A method of adding water until the polymerization product becomes an emulsion can also be applied.

The polymer particle aqueous dispersion has a core / shell structure including a core layer and one or more shell layers covering the core layer from the viewpoint of improving the adhesion of the obtained coating film to the substrate. It is preferable to have. As a method for forming the core / shell structure, multi-stage emulsion polymerization in which emulsion polymerization is carried out in multiple stages is very useful. The core / shell structure can be observed by, for example, morphological observation with a transmission electron microscope or analysis by viscoelasticity measurement.

Specifically, in the multi-stage emulsion polymerization, specifically, for example, as a first step, a hydrolyzable silicon compound and a vinyl compound (or only a hydrolyzable silicon compound) are optionally polymerized in the presence of an emulsifier and water to obtain seed particles. It is formed, and as a second step, a polymerization stock solution containing a hydrolyzable silicon compound and a vinyl compound is added and polymerized in the presence of the seed particles (two-step polymerization method). When three or more stages of multi-stage emulsion polymerization are carried out, for example, as the third stage, a polymerization stock solution containing a hydrolyzable silicon compound and a vinyl compound can be further added for polymerization. Such a method is also suitable from the viewpoint of polymerization stability.

When the two-stage polymerization method is adopted, the mass ratio of the solid content mass (M1) in the polymerization stock solution used in the first step to the solid content mass (M2) in the polymerization stock solution added in the second step (M2). (M1) / (M2)) is preferably 9/1 to 1/9, more preferably 8/2 to 2/8, from the viewpoint of polymerization stability.

If necessary, any known chain transfer agent and / or dispersion stabilizer may be used as the polymerization stock solution for obtaining the polymer particle aqueous dispersion.
The chain transfer agent is not particularly limited, and is, for example, alkyl mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, and t-dodecyl mercaptan; aromatic mercaptans such as benzyl mercaptan and dodecyl benzyl mercaptan; thioalonic acid. Such as thiocarboxylic acids or salts thereof or alkyl esters thereof, or polythiols, diisopropylxanthogen disulfides, di (methylenetrimethylolpropane) xanthogen disulfides and thioglycols, allyl compounds such as dimers of α-methylstyrene and the like. Be done.
The dispersion stabilizer is not particularly limited, and for example, various water-soluble oligomers selected from the group consisting of polycarboxylic acids and sulfonates, polyvinyl alcohol, hydroxyethyl cellulose, starch, maleated polybutadiene, maleized alkyd resin, and the like. Examples thereof include synthetic or natural water-soluble or water-dispersible polymer substances such as polyacrylic acid (salt), polyacrylamide, water-soluble or water-dispersible acrylic resin, and the like.

Other components may be further added to the aqueous dispersion of polymer particles depending on the method of use and the like. Examples of such other components are not particularly limited, but are a curing agent, a metal oxide particle, a thickener, a leveling agent, a tinxing agent, a defoaming agent, a freeze stabilizer, a matting agent, and a cross-linking reaction catalyst. , Pigments, curing catalysts, cross-linking agents, fillers, anti-skinning agents, dispersants, wetting agents, light stabilizers, antioxidants, UV absorbers, leology control agents, antifoaming agents, film-forming aids, rust preventives Agents, dyes, plasticizers, lubricants, reducing agents, preservatives, fungicides, deodorants, anti-yellowing agents, anti-static agents or anti-static agents can be blended.
These optional components can usually be used in an amount of 10 parts by mass or less, 5 parts by mass or less, or 3 parts by mass or less in the aqueous dispersion of polymer particles.

The solid content of the aqueous polymer particle dispersion according to the present invention is not particularly limited as long as it contains 50 to 95% by mass of a water-soluble solvent having a boiling point of less than 100 ° C., but in one embodiment, it is typically 1 to 1. It may be 45% by weight, typically 3-40% by weight.
The polymer particle aqueous dispersion of the present invention described so far is referred to as a polymer particle aqueous dispersion according to the first embodiment.
The aqueous dispersion of polymer particles according to the first embodiment can be used as it is for forming a coating film, or can be mixed with other components as a raw material of a coating composition.

[Coating film]
The coating film of the polymer particle aqueous dispersion according to the present invention can be prepared by applying the polymer particle aqueous dispersion according to the first embodiment to a base material and drying it.

The method of applying the polymer particle aqueous dispersion to the substrate for forming a coating film is not particularly limited, but for example, a spray spraying method, a flow coating method, a roll coating method, a brush coating method, a dip coating method, or a spin. Examples include a coating method, a screen printing method, a casting method, a gravure printing method, and a flexographic printing method.

Further, in one embodiment, the coating film is preferably sintered at a temperature of 500 ° C. or higher.
The sintering temperature is more preferably 500 ° C. or higher and 800 ° C. or lower, and further preferably 600 ° C. or higher and 750 ° C. or lower. Further, it may be sintered by performing treatments such as ultraviolet irradiation of a high-pressure mercury lamp at the same time or in series.
By sintering at the above temperature, the organic matter of the polymer particles is decomposed, so that the water contact angle of the coating film tends to decrease, and the antifouling property tends to improve.
Further, by sintering at the above temperature, the organic matter of the polymer particles is decomposed, and as a result, pores are easily generated inside the film, and the antireflection performance tends to be further improved by lowering the refractive index.

In one embodiment, the coating film is not particularly limited, but from the viewpoint of stable coating film formation, the polymer particle aqueous dispersion according to the first embodiment is further hydrolyzed with the metal oxide particles (A). It is preferably prepared by applying it to a substrate as a coating composition containing the sex silicon compound (C) and drying (sintering) it. As the coating and sintering method in this case, the above-mentioned method can be adopted.
When used as a coating composition containing the metal oxide particles (A) and the hydrolyzable silicon compound (C) in addition to the polymer particle aqueous dispersion according to the first embodiment, this is applied to the second embodiment. It is referred to as such a polymer particle aqueous dispersion.

The metal oxide particles (A) are not particularly limited, and examples thereof include oxides such as silicon, aluminum, titanium, zirconium, zinc, tin, indium, gallium, germanium, antimony, and molybdenum. Silicon oxide is particularly preferable from the viewpoint of optical properties and durability.
In one embodiment, the number average particle size of the metal oxide particles (A) (which may be primary particles, secondary particles or a mixture thereof) may be, for example, 1 nm to 10000 nm. The form of the metal oxide particles (A) is not particularly limited, and examples thereof include powders, dispersions, and sol.
Usually, in the coating composition, the mass ratio of the metal oxide particles (A) and the total amount of solids contained in the aqueous dispersion of the polymer particles according to the first aspect mixed therein is 1/100 to 100. It may be 100/100, preferably 2/100 to 80/100.
Specific examples of the silicon oxide particles are not limited to the following, but for example, "Snowtex-OXS (registered trademark)" manufactured by Nissan Chemical Industries, Ltd., "Snowtex-O (registered trademark)" manufactured by Nissan Chemical Industries, Ltd., and the same company. Examples include "Snowtex-OL (registered trademark)" manufactured by the same company and "Snowtex-OYL (registered trademark)" manufactured by the same company.

In one embodiment, the aqueous dispersion of polymer particles according to the second aspect as a coating composition is a hydrolyzable silicon compound (C) in distinction from the hydrolyzable silicon compound used for polymerizing polymer particles. May be further included. As a result, the coating film of the present embodiment tends to have a higher mechanical strength.

Examples of the hydrolyzable silicon-containing compound used as the hydrolyzable silicon compound (C) include the hydrolyzable silicon-containing compound (c1) represented by the following formula (1) and the hydrolysis represented by the following formula (2). One or more selected from the group consisting of the sex silicon-containing compound (c2) and the hydrolyzable silicon compound (c3) represented by the following formula (3) can be used.
R ¹ _n SiX _4-n (1)
Here, in the formula (1), R ¹ may have a hydrogen atom, a halogen group, a hydroxy group, a mercapto group, an amino group, a (meth) acryloyl group or an epoxy group, and has 1 to 10 carbon atoms. Represents an alkyl group, an alkenyl group, an alkynyl group or an aryl group. X represents a hydrolyzable group, and n is an integer of 0 to 3. The hydrolyzable group is not particularly limited as long as it is a group in which a hydroxyl group is generated by hydrolysis, and examples thereof include a halogen atom, an alkoxy group, an acyloxy group, an amino group, a phenoxy group and an oxime group.
X ₃ Si-R ² _n- SiX ₃ (2)
Here, in the formula (2), X represents a hydrolyzable group, and R ² represents an alkylene group or a phenylene group having 1 to 6 carbon atoms. n is 0 or 1.
R ^3- (O-Si (OR ³ ) ₂ ) _n- OR ³ (3)
Here, in the formula (3), R ³ represents an alkyl group having 1 to 6 carbon atoms. n is an integer of 2-8.

The hydrolyzable silicon compounds (c1) and (c2) are not particularly limited, and are, for example, tetramethoxysilane, tetraethoxysilane, tetra (n-propoxy) silane, tetra (i-propoxy) silane, and tetra (n-butoxy). ) Silane, tetra (i-butoxy) silane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltri Ethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, isobutyltriethoxysilane, cyclohexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethoxysilane, diethoxysilane, methyldimethoxysilane, methyldiethoxysilane, dimethyl Dimethoxysilane, dimethyldiethoxysilane, bis (trimethoxysilyl) methane, bis (triethoxysilyl) methane, bis (triphenyloxysilyl) methane, bis (trimethoxysilyl) ethane, bis (triethoxysilyl) ethane, bis ( Triphenoxysilyl) ethane, 1,3-bis (trimethoxysilyl) propane, 1,3-bis (triethoxysilyl) propane, 1,3-bis (triphenyloxysilyl) propane, 1,4-bis (trimethoxy) Cyril) benzene, 1,4-bis (triethoxysilyl) benzene, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-hydroxypropyltriethoxysilane, 3- Mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxipropyltriethoxysilane Silane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, tetraacetoxysilane, tetrax (trichloroacetoxy) silane, tetrax (trifluoroacetoxy) silane, triacetoxysilane, tris (trichloroacetoxy) silane, Tris (trifluoroacetoxy) silane, methyltriacetoxysilane, methyltris (trichloroacetoxy) silane, tetraclo Losilane, tetrabromosilane, tetrafluorosilane, trichlorosilane, tribromosilane, trifluorosilane, methyltrichlorosilane, methyltribromosilane, methyltrifluorosilane, tetrakis (methylethylketoxim) silane, tris (methylethylketoxim) silane, methyltris (Methylethylketoxim) silane, phenyltris (methylethylketoxim) silane, bis (methylethylketoxim) silane, methylbis (methylethylketoxim) silane, hexamethyldisilazane, hexamethylcyclotrisilazane, bis (dimethylamino) dimethylsilane, bis (diethylamino) ) Dimethylsilane, bis (dimethylamino) methylsilane, bis (diethylamino) methylsilane and the like can be mentioned.

The hydrolyzable silicon compound (c3) is not particularly limited, but for example, a partially hydrolyzed condensate of tetramethoxysilane (for example, a trade name “M silicate 51” manufactured by Tama Chemical Industry Co., Ltd. MSI51 ”, product names“ MS51 ”manufactured by Mitsubishi Chemical Co., Ltd.,“ MS56 ”), partial hydrolysis condensate of tetraethoxysilane (trade name“ Silicate 35 ”, same“ Silicate 45 ”manufactured by Tama Chemical Industry Co., Ltd., Corcote Product name "ESI40", product name "ESI48"), co-hydrolyzed condensate of tetramethoxysilane and tetraethoxysilane (product name "FR-3" manufactured by Tama Chemical Industry Co., Ltd., product manufactured by Corcote Co., Ltd. The name "EMSi48") and the like can be mentioned.

Usually, in the polymer particle aqueous dispersion according to the second aspect as a coating composition, the total amount of solids contained in the polymer particle aqueous dispersion according to the first aspect and the hydrolyzability mixed therein. The mass ratio with the silicon compound (C) may be 100/50 to 100/1000, preferably 100/100 to 100/600.

The coating film of the polymer particle aqueous dispersion according to the present invention can be formed on any known substrate by using the polymer particle aqueous dispersion according to the first aspect or the second aspect. The base material is not particularly limited, and examples thereof include inorganic materials such as glass, and resin materials such as natural resins and synthetic resins. The coating film of the polymer particle aqueous dispersion according to the present invention is suitably applied to a glass substrate having irregularities on the surface such as a textured glass substrate which is a protective cover for a solar cell, particularly in the field of solar cells. ..

The thickness of the coating film of the aqueous dispersion of polymer particles according to the present invention can be appropriately adjusted depending on the application. The average thickness (for example, the average of five randomly selected values) is not particularly limited, but may be, for example, 1 nm to 1000 nm after drying / sintering / cooling, and typically 5 nm to 500 nm. You can do it.

The surface of the coating film of the aqueous dispersion of polymer particles according to the present invention may be water-repellent depending on the intended use. The method of water repellent treatment is not particularly limited, but for example, a silicone-based and / or fluorine-based water repellent can be applied to the surface of the coating film and dried.

The ten-point average roughness (RzJIS) of the surface of the coating film of the polymer particle aqueous dispersion according to the present invention can be appropriately adjusted depending on the application. The ten-point average roughness (RzJIS) is not particularly limited, but may be, for example, 0.01 to 50 μm, and typically 0.02 to 10 μm. By adjusting the ten-point average roughness (RzJIS) of the surface of the coating film, the transparency and antifouling property (surface hydrophilicity or surface water repellency after water repellent treatment) of the coating film can be improved. In order to make the ten-point average roughness (RzJIS) within the above range, the average particle size and amount of the metal oxide particles (A) and the volume average particle size and amount of the polymer particles may be adjusted.

In one embodiment, the coating film of the aqueous dispersion of polymer particles according to the present invention can be imparted with functions excellent in transparency, antireflection properties, and antifouling properties. Therefore, this coating film is particularly suitable as a coating film for a cover glass for a solar cell. That is, in one embodiment, the coating film is preferably formed on the surface of the cover glass for a solar cell.

Hereinafter, the present invention will be described in more detail with reference to specific examples and comparative examples, but the present invention is not limited to the following examples and comparative examples.
Various physical properties and evaluations in the synthetic examples, examples and comparative examples described later were measured and evaluated by the following methods.

(1) Measurement of volume average particle size Using a dynamic light scattering type particle size distribution measuring device UPA-UZ152 (manufactured by Microtrac Bell Co., Ltd.), the volume average particle size of the solid content particles contained in the polymer particle aqueous dispersion Was evaluated.

(2) Measurement of haze For the test plates obtained in Examples and Comparative Examples, haze was measured by the method specified in JIS K7361-1 using a turbidity meter NDH2000 manufactured by Nippon Denshoku Kogyo Co., Ltd., Japan. did.

[Synthesis example]
Hereinafter, examples of synthesizing the aqueous dispersion of polymer particles used in Examples and Comparative Examples described later will be described.

(Synthesis Example 1) Synthesis of Polymer Particle Water Dispersion (B-1) 1000 g of ion-exchanged water and 7 g of dodecylbenzene sulfonic acid were charged into a reactor having a reflux condenser, a dropping tank, a thermometer and a stirrer. Then, the mixture was heated to 80 ° C. with stirring to obtain a mixed solution (1).
The temperature in the reaction vessel of the mixed solution (2) obtained by mixing 250 g of dimethyldimethoxysilane and 200 g of phenyltrimethoxysilane as raw materials for the core layer with the obtained mixed solution (1) was maintained at 80 ° C. In this state, the mixture was added dropwise over about 2 hours to obtain a mixed solution (3).
Then, the mixture (3) was stirred for about 1 hour while the temperature in the reaction vessel was 80 ° C.
Next, the obtained mixed solution (3) was obtained by mixing 15 g of butyl acrylate, 50 g of tetraethoxysilane, 25 g of phenyltrimethoxysilane, and 3 g of 3-methacryloxypropyltrimethoxysilane as raw materials for the shell layer. Mixture (4), diethylacrylamide 30 g, acrylic acid 1 g, reactive emulsifier (trade name "Adecaria Soap SR-1025", manufactured by Asahi Denka Co., Ltd., solid content 25% by mass aqueous solution) 4 g, ammonium persulfate A mixture (5) obtained by mixing 4 g of a 2 mass% aqueous solution and 1000 g of ion-exchanged water is simultaneously added dropwise over about 2 hours while maintaining the temperature in the reaction vessel at 80 ° C. ( 6) was obtained.
Further, as a heat curing, the mixture (6) was stirred for about 2 hours while the temperature in the reaction vessel was 80 ° C. Then, 400 g of tetraethoxysilane was added dropwise to the mixture (6) over about 30 minutes while keeping the temperature in the reaction vessel at 80 ° C. to obtain a mixture (7).
Further, as heat curing, the mixture (7) was stirred for about 2 hours while the temperature in the reaction vessel was 80 ° C. Then, the mixture (7) is cooled to room temperature, filtered through a 100-mesh wire mesh, and the concentration is adjusted with purified water and ethanol to adjust the concentration of the polymer particle aqueous dispersion (B-1) (ethanol concentration 80% by mass, volume average). Particle size 80 nm) was obtained.

(Synthesis Example 2) Synthesis of Polymer Particle Water Dispersion (B-2) 1600 g of ion-exchanged water and 8 g of dodecylbenzene sulfonic acid were charged into a reactor having a reflux condenser, a dropping tank, a thermometer and a stirrer. Then, the mixture was heated to 80 ° C. with stirring to obtain a mixed solution (1).
The temperature in the reaction vessel of the mixed solution (2) obtained by mixing 185 g of dimethyldimethoxysilane and 72 g of phenyltrimethoxysilane as raw materials for the core layer with the obtained mixed solution (1) was maintained at 80 ° C. In this state, the mixture was added dropwise over about 2 hours to obtain a mixed solution (3).
Then, the mixture (3) was stirred for about 1 hour while the temperature in the reaction vessel was 80 ° C. Next, 150 g of butyl acrylate, 30 g of tetraethoxysilane, 92 g of phenyltrimethoxysilane, and 1.3 g of 3-methacryloxypropyltrimethoxysilane were mixed with the obtained mixed solution (3) as raw materials for the shell layer. The obtained mixture (4), diethylacrylamide 165 g, acrylic acid 3 g, reactive emulsifier (trade name "Adecaria Soap SR-1025", manufactured by Asahi Denka Co., Ltd., solid content 25 mass% aqueous solution) 13 g, excess. A mixture (5) obtained by mixing 40 g of a 2 mass% aqueous solution of ammonium sulfate and 1900 g of ion-exchanged water was simultaneously added dropwise over about 2 hours while maintaining the temperature in the reaction vessel at 80 ° C. The mixture (6) was obtained.
Further, as a heat curing, the mixture (6) was stirred for about 2 hours while the temperature in the reaction vessel was 80 ° C. Then, the mixture (6) is cooled to room temperature, filtered through a 100-mesh wire mesh, and the concentration is adjusted with purified water and ethanol to adjust the concentration of the polymer particle aqueous dispersion (B-2) (ethanol concentration 80% by mass, volume average). Particle size 90 nm) was obtained.

(Synthesis Example 3) Synthesis of Polymer Particle Water Dispersion (B-3) 1600 g of ion-exchanged water and 8 g of dodecylbenzene sulfonic acid were charged into a reactor having a reflux condenser, a dropping tank, a thermometer and a stirrer. Then, the mixture was heated to 80 ° C. with stirring to obtain a mixed solution (1).
The temperature in the reaction vessel of the mixed solution (2) obtained by mixing 185 g of dimethyldimethoxysilane and 72 g of phenyltrimethoxysilane as raw materials for the core layer with the obtained mixed solution (1) was maintained at 80 ° C. In this state, the mixture was added dropwise over about 2 hours to obtain a mixed solution (3).
Then, the mixture (3) was stirred for about 1 hour while the temperature in the reaction vessel was 80 ° C. Next, 150 g of butyl acrylate, 30 g of tetraethoxysilane, 92 g of phenyltrimethoxysilane, and 1.3 g of 3-methacryloxypropyltrimethoxysilane were mixed with the obtained mixed solution (3) as raw materials for the shell layer. The obtained mixture (4), diethylacrylamide 165 g, acrylic acid 3 g, reactive emulsifier (trade name "Adecaria Soap SR-1025", manufactured by Asahi Denka Co., Ltd., solid content 25 mass% aqueous solution) 13 g, excess. A mixture (5) obtained by mixing 40 g of a 2 mass% aqueous solution of ammonium sulfate and 1900 g of ion-exchanged water was simultaneously added dropwise over about 2 hours while maintaining the temperature in the reaction vessel at 80 ° C. The mixture (6) was obtained. Then, 400 g of tetraethoxysilane was added dropwise to the mixture (6) over about 30 minutes while keeping the temperature in the reaction vessel at 80 ° C. to obtain a mixture (7).
Further, as heat curing, the mixture (7) was stirred for about 2 hours while the temperature in the reaction vessel was 80 ° C. Then, the mixture (7) is cooled to room temperature, filtered through a 100-mesh wire mesh, and the concentration is adjusted with purified water and ethanol to adjust the concentration of the polymer particle aqueous dispersion (B-3) (ethanol concentration 80% by mass, volume average). Particle size 110 nm) was obtained.

(Synthesis Example 4) Synthesis of Polymer Particle Water Dispersion (B-4) 1000 g of ion-exchanged water and 7 g of dodecylbenzene sulfonic acid were charged into a reactor having a reflux condenser, a dropping tank, a thermometer and a stirrer. Then, the mixture was heated to 80 ° C. with stirring to obtain a mixed solution (1).
The temperature in the reaction vessel of the mixed solution (2) obtained by mixing 250 g of dimethyldimethoxysilane and 200 g of phenyltrimethoxysilane as raw materials for the core layer with the obtained mixed solution (1) was maintained at 80 ° C. In this state, the mixture was added dropwise over about 2 hours to obtain a mixed solution (3).
Then, the mixture (3) was stirred for about 1 hour while the temperature in the reaction vessel was 80 ° C.
Next, the obtained mixed solution (3) was obtained by mixing 15 g of butyl acrylate, 50 g of tetraethoxysilane, 25 g of phenyltrimethoxysilane, and 3 g of 3-methacryloxypropyltrimethoxysilane as raw materials for the shell layer. Mixture (4), diethylacrylamide 30 g, acrylic acid 1 g, reactive emulsifier (trade name "Adecaria Soap SR-1025", manufactured by Asahi Denka Co., Ltd., solid content 25% by mass aqueous solution) 4 g, ammonium persulfate A mixture (5) obtained by mixing 4 g of a 2 mass% aqueous solution and 1000 g of ion-exchanged water is simultaneously added dropwise over about 2 hours while maintaining the temperature in the reaction vessel at 80 ° C. ( 6) was obtained.
Further, as a heat curing, the mixture (6) was stirred for about 2 hours while the temperature in the reaction vessel was 80 ° C. Then, 200 g of tetraethoxysilane was added dropwise to the mixture (6) over about 30 minutes while keeping the temperature in the reaction vessel at 80 ° C. to obtain a mixture (7).
Further, as heat curing, the mixture (7) was stirred for about 2 hours while the temperature in the reaction vessel was 80 ° C. Then, the mixture (7) is cooled to room temperature, filtered through a 100-mesh wire mesh, and the concentration is adjusted with purified water and ethanol to adjust the concentration of the polymer particle aqueous dispersion (B-4) (ethanol concentration 80% by mass, volume average). Particle size 70 nm) was obtained.

[Example 1]
The aqueous dispersion of polymer particles (B-1) synthesized in (Synthesis Example 1) (ethanol concentration 80% by mass, volume average particle diameter 80 nm) is diluted with water until the ethanol concentration reaches 10%, and the particle size is measured. As a result, the volume average particle size was 100 nm, and the rate of change in the volume average particle size before and after dilution with water was 125%. The water dilution here was carried out by adding distilled water to the aqueous dispersion of polymer particles stirred with a stirrer to adjust the concentration.
Further, the polymer particle aqueous dispersion (B-1) was adjusted to a solid content concentration of 3% and an ethanol concentration of 80%, and the rotation speed was 1000 rpm using a spin coater on one side of the base material (white plate of 10 cm × 10 cm). After coating for 10 seconds at 100 ° C., the mixture was dried at 100 ° C. for 1 minute to obtain a test plate having a coating film (F-1). Further, the test plate having the coating film (F-1) is sintered in an electric furnace at 700 ° C. for 3 minutes, and then rapidly cooled to mean the average film thickness (the average of the values at 5 randomly selected points (the same applies hereinafter). ).) A test plate (G-1) having a coating film of 100 nm was obtained. The haze of the test plate (G-1) was 0.9%, showing very good optical characteristics.

[Example 2]
Water-dispersed colloidal silica having a number average particle diameter of 5 nm as metal oxide particles (A) on the polymer particle aqueous dispersion (B-1) (trade name "Snowtex OXS", manufactured by Nissan Chemical Industries, Ltd., solid content 10% by mass), tetraethoxysilane was added as the hydrolyzable silicon compound (C), and the ethanol concentration was adjusted to 80% to obtain a polymer particle aqueous dispersion (B-3) (volume average particle diameter 90 nm). At this time, the composition ratio (mass ratio of each component calculated in terms of solid content) in the polymer particle aqueous dispersion (B-3) is (A) / (B-1) / (C) = 20/100 /. It was 180. The aqueous dispersion of polymer particles (B-3) was diluted with water until the ethanol concentration reached 10%, and the particle size was measured. As a result, the volume average particle size was 110 nm, and the change in volume average particle size before and after water dilution. The rate was 122%.
Further, the polymer particle aqueous dispersion (B-3) was adjusted to a solid content concentration of 3% and an ethanol concentration of 80%, and a spin coater was used on one side of the base material (white plate of 10 cm × 10 cm) at a rotation speed of 1000 rpm for 10 sec. After coating, it was dried at 100 ° C. for 1 minute to obtain a test plate having a coating film (F-2). At this time, the composition ratio in the coating film (F-2) is (A) / (B) / (C) = 20 in the same manner as the mass ratio of each component calculated in terms of solid content of the polymer particle aqueous dispersion. It is considered to be / 100/180. Here, (A) is the mass ratio of the silica fine particles (A) obtained after the drying, and (B) is the mass ratio of the polymer particles (B) obtained after the drying, and (C). Is the mass ratio of the hydrolyzed condensate of the hydrolyzable silicon compound (C) obtained after drying. Further, the test plate having the coating film (F-2) was sintered in an electric furnace at 700 ° C. for 3 minutes, and then rapidly cooled to obtain a test plate (G-2) having a coating film having an average film thickness of 100 nm. The haze of the test plate (G-2) was 0.3%, showing very good optical characteristics.

[Example 3]
The aqueous dispersion of polymer particles (B-4) synthesized in (Synthesis Example 4) (ethanol concentration 80% by mass, volume average particle diameter 70 nm) is diluted with water until the ethanol concentration reaches 10%, and the particle size is measured. As a result, the volume average particle size was 133 nm, and the rate of change in the volume average particle size before and after dilution with water was 190%.
Further, the polymer particle aqueous dispersion (B-4) was adjusted to a solid content concentration of 3% and an ethanol concentration of 80%, and the rotation speed was 1000 rpm using a spin coater on one side of the base material (white plate of 10 cm × 10 cm). After coating for 10 seconds at 100 ° C., the mixture was dried at 100 ° C. for 1 minute to obtain a test plate having a coating film (F-3). Further, a test plate having a coating film (F-3) was sintered in an electric furnace at 700 ° C. for 3 minutes, and then rapidly cooled to obtain a test plate (G-3) having a coating film having an average film thickness of 100 nm. The haze of the test plate (G-3) was 3.0%, showing good optical characteristics.

[Comparative Example 1]
The aqueous dispersion of polymer particles (B-2) synthesized in (Synthesis Example 2) (ethanol concentration 80% by mass, volume average particle diameter 90 nm) is diluted with water until the ethanol concentration reaches 10%, and the particle size is measured. As a result, the volume average particle size was 250 nm, and the rate of change in the volume average particle size before and after dilution with water was 278%.
Further, the polymer particle aqueous dispersion (B-2) was adjusted to a solid content concentration of 3% and an ethanol concentration of 80%, and the rotation speed was 1000 rpm using a spin coater on one side of the base material (white plate of 10 cm × 10 cm). After coating for 10 seconds at 100 ° C., the mixture was dried at 100 ° C. for 1 minute to obtain a test plate having a coating film (F-4). Further, a test plate having a coating film (F-4) was sintered in an electric furnace at 700 ° C. for 3 minutes, and then rapidly cooled to obtain a test plate (G-4) having a coating film having an average film thickness of 100 nm. The haze of the test plate (G-4) was 20.5%, and the coating film was cloudy.

[Comparative Example 2]
The aqueous dispersion of polymer particles (B-3) synthesized in (Synthesis Example 3) (ethanol concentration 80% by mass, volume average particle diameter 110 nm) is diluted with water until the ethanol concentration reaches 10%, and the particle diameter is measured. As a result, the volume average particle size was 230 nm, and the rate of change in the volume average particle size before and after dilution with water was 209%.
Further, the polymer particle aqueous dispersion (B-3) was adjusted to a solid content concentration of 3% and an ethanol concentration of 80%, and the rotation speed was 1000 rpm using a spin coater on one side of the base material (white plate of 10 cm × 10 cm). After coating for 10 seconds at 100 ° C., the mixture was dried at 100 ° C. for 1 minute to obtain a test plate having a coating film (F-5). Further, a test plate having a coating film (F-5) was sintered in an electric furnace at 700 ° C. for 3 minutes, and then rapidly cooled to obtain a test plate (G-5) having a coating film having an average film thickness of 100 nm. The haze of the test plate (G-5) was 11.3%, and the coating film was cloudy.

Since the coating film of the present invention has excellent optical characteristics, it has industrial applicability as an antifouling film and an antireflection film for solar cells, mirrors for solar thermal power generation, and the like.

Claims (1)

A polymer particle aqueous dispersion containing 50 to 95% by mass of a water-soluble solvent having a boiling point of less than 100 ° C., diluted with water until the concentration of the water-soluble solvent in the polymer particle aqueous dispersion reaches 10% by mass. The volume average particle size of the solid content particles contained in the aqueous dispersion of the polymer particles was 50 to 200% of the volume average particle size before water dilution.
The polymer particle aqueous dispersion is a vinyl having at least one hydrolyzable silicon compound containing a hydrolyzable silicon compound containing four or more hydrolyzable functional groups and a secondary amide group and / or a tertiary amide group. A polymer particle aqueous dispersion obtained by polymerizing a monomer.