JP7379209B2 - Method for producing organic-inorganic composite particles - Google Patents

Description

The present invention relates to a method for producing organic-inorganic composite particles. More specifically, the present invention relates to a method for producing organic-inorganic composite particles that does not use an organic solvent in the surface treatment step and polymerization step of the inorganic particles.

Traditionally, silica particles and glass have been used to improve mechanical strength, optical properties, thermal properties, etc. in cosmetics, paint compositions, heat-insulating resin compositions, light-diffusing resin compositions, light-diffusing films, etc. Inorganic fine particles such as particles, titanium oxide, aluminum oxide, and calcium carbonate are used as additives. This additive takes advantage of the properties of inorganic materials. Furthermore, organic-inorganic composite particles have been proposed that utilize not only the characteristics of the inorganic material but also the characteristics of the organic material by combining an inorganic material and an organic material.
Organic-inorganic composite particles are, for example, disclosed in Japanese Patent No. 3437881 (Patent Document 1), Japanese Patent Application Publication No. 5-209027 (Patent Document 2), Japanese Patent Application Publication No. 7-17820 (Patent Document 3), and Japanese Patent No. 6301639 (Patent Document 3). This is proposed in Reference 4).
In Patent Documents 1 to 3, inorganic particles such as colloidal silica treated with a silicon-based compound and a polymerizable monomer are dispersed in a solvent, and after the solvent is distilled off, the polymerizable monomer is polymerized. Thus, a method for producing organic-inorganic composite particles is described.
Patent Document 4 describes a method for producing organic-inorganic composite particles by polymerizing a silica-dispersed monomer in which silica particles are dispersed in a monomer to which an organic solvent, isopropyl alcohol, is added.
Here, since colloidal silica and silica particles are dispersed in an organic solvent such as isopropyl alcohol, the solvent during polymerization also contains this organic solvent.

Patent No. 3437881 Japanese Patent Application Publication No. 5-209027 Japanese Unexamined Patent Publication No. 7-17820 Patent No. 6301639

In Patent Documents 1 to 3, an organic solvent is used for dispersing colloidal silica, and in Patent Document 4, since an organic solvent is added to the monomer, it was necessary to distill off the organic solvent. Distillation complicates the manufacturing process of organic-inorganic composite particles and increases manufacturing costs, which is industrially disadvantageous. Furthermore, it is desirable to avoid using organic solvents as much as possible from the viewpoint of the impact on the manufacturer during production and the negative impact on the environment.
Therefore, it has been desired to provide a method for producing organic-inorganic composite particles that does not use organic solvents.

The inventors of the present invention have discovered that by treating the surface of inorganic particles with a silicon compound and an organic acid in a polymerizable monomer, they can be dispersed in a polymerizable monomer without using an organic solvent. The present invention was achieved by unexpectedly discovering that stability can be ensured.
Thus, according to the present invention, a surface treatment step of treating the surface of an inorganic particle with a silicon-based compound and an organic acid in a polymerizable monomer in the absence of an organic solvent; A polymerizable monomer composition containing a polymerizable monomer and a polymerizable monomer is suspended in an aqueous dispersion medium containing a suspension stabilizer, and the polymerizable monomer is polymerized to obtain organic-inorganic composite particles. Provided is a method for producing organic-inorganic composite particles, the method comprising:

According to the present invention, since no organic solvent is used in the production of organic-inorganic composite particles, distillation of the organic solvent is not necessary, and a method for producing organic-inorganic composite particles that is friendly to manufacturers and the environment can be provided.
Moreover, in any of the following cases, a more suitable method for producing organic-inorganic composite particles can be provided.
(1) The organic acid is selected from phosphoric acid compounds, carboxylic acid compounds, and sulfonic acid compounds.
(2) The organic acid has the following general formula (I):

(In the formula, R ¹ is an alkyl group, vinyl group, allyl group, or (meth)acryloyl group having 1 to 20 carbon atoms, R ² is a divalent group derived from an alkane having 1 to 4 carbon atoms, and R ³ is a divalent group having 1 to 4 carbon atoms. -8 divalent group derived from an alkane, m is 0-30, n is 0-5, a is 1-3, b is greater than 0 and less than or equal to 2, and a+b is 3) It is.
(3) The organic acid is used in an amount of 0.01 to 5 parts by weight per 100 parts by weight of the polymerizable monomer composition.
(4) The inorganic particles are hydrophilic silica particles having a primary average particle diameter of 1 to 100 nm, and the organic-inorganic composite particles have a volume average particle diameter of 1 to 100 μm.
(5) 15 to 200 parts by weight of inorganic particles are used per 100 parts by weight of the polymerizable monomer.
(6) The silicon-based compound is used in an amount of 0.1 to 30 parts by weight per 100 parts by weight of the inorganic particles.
(7) The suspension stabilizer is a poorly water-soluble inorganic compound, and is used in an amount of 0.1 to 30 parts by weight per 100 parts by weight of the polymerizable monomer composition.

The method for producing organic-inorganic composite particles of the present invention includes a surface treatment step of treating the surface of the inorganic particle with a silicon-based compound and an organic acid in a polymerizable monomer in the absence of an organic solvent; A polymerizable monomer composition containing treated inorganic particles and a polymerizable monomer is suspended in an aqueous dispersion medium containing a suspension stabilizer, and the polymerizable monomer is polymerized to form organic-inorganic composite particles. a polymerization step to obtain. Since the organic-inorganic composite particles can be produced by the above two steps in the absence of an organic solvent, the production method of the present invention does not require distillation of the organic solvent, and is friendly to the manufacturer and the environment.

(1) Surface treatment step (1-1) Organic solvent The organic solvent refers to an organic solvent that does not cause any reaction during the production of organic-inorganic composite particles. The property that no reaction occurs can be expressed as "non-reactive", "inert", "non-polymerizable", etc.
Examples of organic solvents that are not present in the surface treatment process include alcohols such as methanol, ethanol, propanol, and isopropanol, butane, pentane, hexane, cyclohexane, heptane, decane, hexadecane, toluene, xylene, ethyl acetate, and acetic acid. Examples include butyl, methyl ethyl ketone, methyl isobutyl ketone, 1,4-dioxane, methyl chloride, methylene chloride, chloroform, carbon tetrachloride and the like.

(1-2) Polymerizable monomer The polymerizable monomer is not particularly limited as long as it can be suspended polymerized, and various commonly used vinyl monomers can be used. Can be used. Examples of the monomer include monofunctional monomers having one or more vinyl groups, crosslinkable monomers having two or more vinyl groups, and the like.
Examples of monofunctional monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, dimethylstyrene, ethylstyrene, propylstyrene, pt-butylstyrene, p-methylstyrene, - Styrenic monomers such as methoxystyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, bromostyrene; methyl acrylate, ethyl acrylate, propyl acrylate, n- acrylate Butyl, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, tetrahydrofurfuryl acrylate, stearyl acrylate, cetyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylic acid (Meth)acrylic acid esters such as propyl, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, tetrahydrofurfuryl methacrylate, stearyl methacrylate, cetyl methacrylate, etc. Monomers: acrylic acid, methacrylic acid, vinyl chloride, vinyl acetate, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, N-vinylpyrrolidone, dimethyl maleate, dimethyl fumarate, diethyl fumarate, ethyl fumarate, anhydrous Examples include maleic acid and N-vinylcarbazole. Monofunctional monomers can be used alone or in combination of two or more.

The crosslinkable monomer can impart solvent resistance to the organic-inorganic composite particles when the organic-inorganic composite particles contain a component derived therefrom.
Examples of the crosslinkable monomer include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, Polyethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, allyl(meth)acrylate, t-butylaminoethyl(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,3-butanediol di( Diethylenically unsaturated carboxylic acid esters such as meth)acrylate, N,N-divinylaniline, divinyl ether, divinyl sulfide, divinylsulfone, N,N'-methylenebis(meth)acrylamide, N,N'-ethylenebis(meth) Examples include acrylamide. The crosslinkable monomers can be used alone or in combination of two or more.
The crosslinking monomer is preferably used in an amount of 100 parts by weight or less based on 100 parts by weight of the monofunctional monomer. If the amount is more than 100 parts by weight, a hard and brittle polymer will be obtained, which is not preferred in practice. The amount used is more preferably 50 parts by weight or less, and even more preferably 30 parts by weight or less.

(1-3) Inorganic particles The inorganic particles preferably have a primary average particle diameter. It is preferable that the inorganic particles have a primary average particle diameter as small as possible. "As small as possible" means as small as possible. Specifically, the primary average particle diameter is preferably 100 nm or less. If the primary average particle diameter is larger than 100 nm, the specific surface area becomes small, resulting in a decrease in the adhesive interface with the resin, and sufficient mechanical properties may not be obtained. The primary average particle diameter is preferably 1 to 100 nm. The primary average particle diameter is more preferably 1 to 50 nm.
Examples of inorganic particles include silica particles mainly composed of SiO ₂ . Silica particles can be obtained, for example, by gelling a silica precursor. Examples of the silica precursor include silicon alkoxides having one or more silicon atoms and an alkoxy group (eg, 1 to 4 carbon atoms) in the same molecule. Specific examples include tetraethoxysilane (TEOS), tetramethoxysilane, and tetrapropoxysilane. Further, oligomers such as methyl silicate oligomer, which is a partially hydrolyzed oligomer of tetramethoxysilane, ethyl silicate oligomer, which is partially hydrolyzed oligomer of tetraethoxysilane, and siloxane oligomer, may be mentioned.
Preferably, the inorganic particles are hydrophilic silica particles. Examples of hydrophilic silica particles include hydrophilic fumed silica AEROSIL (trade name) series commercially available from EVONIK (for example, OX-50, 50, 90G, 130, 150, 200, 255, 300, 380, TT600, 200F, 380F, 200Pharma, 300Pharma, etc.), and hydrophilic grades of highly dispersed silica WACKER HDK (trade name) commercially available from Asahi Kasei Corporation (for example, HDKN20, HDKT30, HDKT40, HDKV15, etc.). These hydrophilic silica particles can be used alone or in combination. Note that hydrophilicity can be defined by the hydrophobicity index measured by the method described in the Examples section. That is, a higher hydrophobic index means lower hydrophilicity, and a lower hydrophobic index means higher hydrophilicity. The hydrophobic index is preferably in the range of 20 or less, more preferably in the range of 0 to 20.

The inorganic particles are preferably used in an amount of 15 to 200 parts by weight based on 100 parts by weight of the polymerizable monomer. If the amount used is less than 15 parts by weight, the strength of the organic-inorganic composite particles may become insufficient. If the amount used is more than 200 parts by weight, depending on the specific surface area of the inorganic particles, the fluidity of the composition containing the polymerizable monomer and inorganic particles becomes too low, making it impossible to perform emulsification treatment before suspension polymerization. It may disappear. The amount used is more preferably 20 to 150 parts by weight, and even more preferably 25 to 100 parts by weight.

(1-4) Silicon-based compounds Examples of silicon-based compounds include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, Alkoxysilanes such as n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, 1,6-bis(trimethoxysilyl)hexane, trifluoropropyltrimethoxysilane, , silazane such as hexamethyldisilazane, chlorosilane such as trimethylsilylchloride, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxy Silane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3 -Methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyl Dimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl -butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-ureidopropyltrialkoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane Examples include silane coupling agents such as methoxysilane, bis(triethoxysilylpropyl)tetrasulfide, and 3-isocyanatepropyltriethoxysilane. The silicon-based compounds can be used alone or in combination of two or more.
The silicon-based compound is preferably used in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the inorganic particles. If the amount used is less than 0.1 part by weight, the surface treatment of the inorganic particles will be insufficient and the inorganic particles may flow out into the aqueous medium during the suspension polymerization process, which is not preferable. If the amount used is more than 30 parts by weight, the effect will not improve much even if the amount added is increased, which is not preferable. The amount used is more preferably 3 to 25 parts by weight, and even more preferably 5 to 20 parts by weight.

(1-5) Organic acid Organic acids are used to perform hydrolysis and/or condensation reactions of silicon compounds. Examples of organic acids include phosphoric acid compounds, carboxylic acid compounds, and sulfonic acid compounds. Organic acids can be used alone or in combination of two or more.
Examples of the phosphoric acid compound include phosphorous acid monoester, phosphorous acid diester, phosphoric acid monoester, and phosphoric acid diester.
The phosphoric acid compound has the following general formula (I):

(In the formula, R ¹ is an alkyl group, vinyl group, allyl group, or (meth)acryloyl group having 1 to 20 carbon atoms, R ² is a divalent group derived from an alkane having 1 to 4 carbon atoms, and R ³ is a divalent group having 1 to 4 carbon atoms. -8 divalent group derived from an alkane, m is 0-30, n is 0-5, a is 1-3, b is greater than 0 and less than or equal to 2, and a+b is 3) It is preferable that
The acidic phosphoric acid ester represented by the above general formula (I) includes various compounds depending on the selection of R ¹ to R ³ , m, n, a and b. The organic acid may be a mixture of multiple compounds. In the case of a plurality of mixtures, m, n, a and b can take on values other than integers.
Examples of the alkyl group for R ¹ include methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, hexadecyl, octadecyl, and the like. These alkyl groups may include structural isomers, if possible.
Examples of R ² include methylene, ethylene, trimethylene, tetramethylene, and the like. R ² may include structural isomers where possible.
Examples of R ³ include methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, and the like. R ³ may include structural isomers where possible.

More specific acidic phosphoric acid esters include lauryl phosphoric acid, polyoxyethylene (1) lauryl ether phosphoric acid, dipolyoxyethylene (2) alkyl ether phosphoric acid, dipolyoxyethylene (4) alkyl ether phosphoric acid, Dipolyoxyethylene (6) alkyl ether phosphoric acid, dipolyoxyethylene (8) alkyl ether phosphoric acid, dipolyoxyethylene (4) nonylphenyl ether phosphoric acid, caprolactone EO modified phosphoric acid dimethacrylate, 2-methacryloyloxyethyl Examples include acid phosphate. (Number) means the number of repetitions of oxyethylene. EO means ethylene oxide.
Examples of carboxylic acid compounds include formic acid, glacial acetic acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, oxalic acid, benzoic acid, propionic acid, butyric acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, Examples include nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, heptadecanoic acid, stearic acid, glycolic acid, perfluorobutyric acid, and the like. In addition, acrylic acid, methacrylic acid, maleic acid, itaconic acid, maleic acid monomethyl ester, citraconic acid monomethyl ester, 2-carboxyethyl acrylate, 2-carboxyethyl methacrylate, mono(2-acryloyloxyethyl) succinate, succinate Acid mono(2-methacryloyloxyethyl) may be used alone or in combination of two or more.
Examples of sulfonic acid compounds include sulfuric acid, fluorosulfonic acid, methanesulfonic acid, ethanesulfonic acid, alkylsulfonic acid compounds such as 1-propanesulfonic acid, benzenesulfonic acid, dodecylbenzenesulfonic acid, and p-toluenesulfonic acid. , 4-ethylbenzenesulfonic acid, p-chlorobenzenesulfonic acid, m-xylene-4-sulfonic acid, 3-pyridinesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, 1-pyrenesulfonic acid, and other arylsulfonic acids. Examples include such compounds. Other examples include styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid. It will be done.

The organic acid is preferably used in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the polymerizable monomer composition. When the amount used is less than 0.01 part by weight, the rate of the silane coupling reaction may become slow and the reaction may take some time. If the amount used is more than 5 parts by weight, it is not preferable because the effect commensurate with the amount used cannot be obtained and it is uneconomical in terms of cost. The amount used is more preferably 0.05 to 1 part by weight, and even more preferably 0.1 to 0.2 part by weight.
The organic acid may be used in combination with, for example, a hydrohalic acid such as hydrochloric acid, hydrofluoric acid, or hydrobromic acid, or an inorganic acid such as sulfuric acid, nitric acid, or phosphoric acid.

(1-6) Surface treatment conditions The surface treatment conditions are not particularly limited, and the surface of the inorganic particles is treated with a silicon-based compound and an organic acid by stirring under conditions in which the polymerizable monomer does not polymerize. Can be processed. For example, in the surface treatment step, inorganic particles, silicon-based compounds (excluding silica particles), and organic acids are mixed in a polymerizable monomer without the presence of the organic solvent listed in (1-1) above. and mixed for a predetermined time at a predetermined temperature range. The predetermined temperature is preferably 10°C or more and 100°C or less. By such mixing, the surfaces of the inorganic particles are treated with the silicon-based compound and the organic acid. A polymerizable monomer composition is obtained by such mixing. The polymerizable monomer composition is a composition containing at least surface-treated inorganic particles and a polymerizable monomer.

In the surface treatment step, an aluminum compound (aluminum coupling agent) may be added to the solution of the heavy monomer in addition to the silicon compound and the organic acid. Examples of the aluminum compound include acetoalkoxyaluminum diisopropylate, aluminum diisopropoxymonoethyl acetoacetate, aluminum trisethyl acetoacetate, aluminum trisacetylacetonate, and the like.

(2) Polymerization process In the polymerization process, a polymerizable monomer composition containing surface-treated inorganic particles and a polymerizable monomer is suspended in an aqueous dispersion medium containing a suspension stabilizer. This is a process of obtaining organic-inorganic composite particles by polymerizing the particles. The aqueous dispersion medium is a medium containing an aqueous medium and a suspension stabilizer. In the polymerization step, the polymerizable monomer composition formed in the surface treatment step (1) is dispersed in an aqueous dispersion medium to form an emulsion, and the emulsion is diffused under predetermined temperature conditions. Polymerize the polymerizable monomer. The predetermined temperature conditions may include a temperature profile.
(2-1) Aqueous medium Water is preferred as the aqueous medium. The aqueous medium is preferably used in an amount of 100 parts by weight or more based on 100 parts by weight of the polymerizable monomer composition.
(2-2) Suspension stabilizer Suspension stabilizers contained in the aqueous dispersion medium include, for example, phosphates such as calcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium pyrophosphate, magnesium pyrophosphate, Pyrophosphates such as aluminum pyrophosphate and zinc pyrophosphate, poorly water-soluble inorganic compounds such as calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, and colloidal silica. can be mentioned. Suspension stabilizers can be used alone or in combination of two or more. Among these, it is preferable to use inorganic compounds that can be easily dissolved and removed by adjusting the pH of the system after the completion of polymerization. Examples of such inorganic compounds include tribasic calcium phosphate, magnesium pyrophosphate produced by a secondary decomposition method, calcium pyrophosphate, and colloidal silica. With these, the desired resin particles can be obtained more stably.
The suspension stabilizer is preferably used in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the polymerizable monomer composition. If the amount used is less than 0.1 part by weight, sufficient dispersion may not be possible. If the amount used is more than 30 parts by weight, it is not preferable because the effect commensurate with the amount used cannot be obtained and it is uneconomical in terms of cost. The amount used is preferably 0.5 to 20 parts by weight, and even more preferably 1 to 15 parts by weight.

(2-3) Other components (2-3-1) Surfactant The aqueous medium contains surfactants such as anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. An agent may be added.
Examples of anionic surfactants include fatty acid oils such as sodium oleate and potassium castor oil, alkyl sulfate ester salts such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkyl sulfonic acids. salts, alkylnaphthalene sulfonates, alkanesulfonates, dialkyl sulfosuccinates, alkyl phosphate ester salts, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkylphenyl ether sulfate ester salts, polyoxyethylene alkyl sulfate ester salts, etc. Can be mentioned.
Examples of nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkyl amine, glycerin fatty acid ester, Examples include ethylene-oxypropylene block polymer.
Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride.
Examples of the zwitterionic surfactant include lauryl dimethylamine oxide and phosphate or phosphite surfactants.
The above surfactants can be used alone or in combination of two or more.
The surfactant is preferably used in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the polymerizable monomer composition. If the amount used is less than 0.01 parts by weight, a sufficient dispersion effect may not be obtained. If the amount used is more than 5 parts by weight, it is not preferable because the effect commensurate with the amount used cannot be obtained and it is uneconomical in terms of cost. The amount used is more preferably 0.05 to 3 parts by weight.

(2-3-2) Polymerization initiator The polymerizable monomer composition may contain a polymerization initiator. A polymerization initiator may be added to the polymerizable monomer composition in the surface treatment step. A polymerization initiator may be added to the solution after the surface treatment step. A polymerization initiator may be added to the emulsion during the polymerization step.
The polymerization initiator is not particularly limited, and includes, for example, persulfates such as ammonium persulfate, potassium persulfate, and sodium persulfate, cumene hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, and benzoyl peroxide. , lauroyl peroxide, dimethylbis(t-butylperoxy)hexane, dimethylbis(t-butylperoxy)hexyne-3, bis(t-butylperoxyisopropyl)benzene, bis(t-butylperoxy)trimethylcyclohexane , organic peroxides such as butyl-bis(t-butylperoxy)valerate, t-butyl 2-ethylhexane peroxyate, dibenzoyl peroxide, paramenthane hydroperoxide, t-butyl peroxybenzoate, 2, 2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] disulfate dihydrate, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] hydrate, 2,2'-azobis{2 -[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane} dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2' -Azobis(1-imino-1-pyrrolidino-2-ethylpropane) dihydrochloride, 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propion amide}, 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], 4,4'-azobis(4-cyanopentanoic acid), 2,2'-azobisisobutyro Nitrile, 2,2'-azobis(2-methyl-butyronitrile), 2,2'-azobis(2-isopropylbutyronitrile), 2,2'-azobis(2,3-dimethylbutyronitrile), 2, 2'-azobis(2,4-dimethylbutyronitrile), 2,2'-azobis(2-methylcapronitrile), 2,2'-azobis(2,3,3-trimethylbutyronitrile), 2 , 2'-azobis(2,4,4-trimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-ethoxyvaleronitrile) nitrile), 2,2'-azobis(2,4-dimethyl-4-n-butoxyvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'- Azobis[N-(2-propenyl)-2-methylpropionamide], 2,2'-azobis(N-butyl-2-methylpropionamide), 2,2'-azobis(N-cyclohexyl-2-methylpropion) amide), 1,1'-azobis(1-acetoxy-1-phenylethane), 1,1'-azobis(cyclohexane-1-carbonitrile), dimethyl-2,2'-azobis(2-methylpropinate) , dimethyl-2,2'-azobisisobutyrate, dimethyl-2,2'-azobis(2-methylpropionate), 2-(carbamoylazo)isobutyronitrile, 4,4'-azobis(4 Examples include radical polymerization initiators such as azo compounds such as -cyanovaleric acid).
Polymerization initiators can be used alone or in combination of two or more. The polymerization initiator is preferably used in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the polymerizable monomer composition. If the amount used is less than 0.01 parts by weight, polymerization may not proceed sufficiently. If the amount used is more than 10 parts by weight, it is not preferable because the effect commensurate with the amount used cannot be obtained and it is uneconomical in terms of cost. The amount used is more preferably 0.1 to 5 parts by weight.

(2-3-3) Polymerization inhibitor Suspension polymerization of polymerizable monomers in an aqueous medium is carried out in the presence of a water-soluble polymerization inhibitor in order to suppress the generation of emulsion polymerization products in an aqueous system. You may go. Here, water-soluble means that 1 g or more is dissolved in 100 g of water at 25°C.
Examples of water-soluble polymerization inhibitors include nitrites, sulfites, hydroquinones, ascorbic acids, water-soluble B vitamins, citric acid, and polyphenols. The amount of the polymerization inhibitor added is preferably within the range of 0.02 to 0.2 parts by weight based on 100 parts by weight of the polymerizable monomer composition.

(3) Other steps After the polymerization step, a step of decomposing the suspension stabilizer, a step of centrifugation, a step of washing with water, a step of drying, etc. may be performed as necessary.
In the step of decomposing the suspension stabilizer, for example, inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, etc. can be used for decomposition.

(4) Organic-inorganic composite particles (4-1) Shape The shape of the organic-inorganic composite particles is not particularly limited, but is preferably spherical.
The organic-inorganic composite particles preferably have an average particle diameter of 1 to 100 μm. When the average particle diameter is less than 1 μm, it may be difficult to exhibit the physical properties derived from the organic-inorganic composite particles. If it is larger than 100 μm, the appearance of the member using the organic-inorganic composite particles may be adversely affected. The average particle diameter is preferably 3 to 80 μm.
(4-2) Content of inorganic components The organic-inorganic composite particles preferably contain 5 to 80% by weight of inorganic components derived from inorganic particles. If the content is less than 5% by weight, the effect of improving mechanical properties may not be sufficiently achieved. When it is more than 80% by weight, the proportion of the polymerizable monomer serving as a dispersion medium decreases, and the inorganic particles may not be sufficiently dispersed. The content ratio is more preferably 7 to 50% by weight, and even more preferably 10 to 40% by weight. Note that the content ratio means the ratio of the amount of residue after removing the organic component by firing the organic-inorganic composite particles to the organic-inorganic composite particles.

(4-3) Applications Organic-inorganic composite particles can be used in cosmetics, paint compositions, heat-insulating resin compositions, light-diffusing resin compositions, light-diffusing films, and the like.
(4-3-1) Cosmetic The cosmetic preferably contains organic-inorganic composite particles in a range of 1 to 40% by weight.
Cosmetics include soaps, body shampoos, facial cleansing creams, cleaning cosmetics such as facial scrubs, lotions, creams, milky lotions, packs, powders, foundations, lipsticks, lip balms, blushers, eyebrow cosmetics, manicure cosmetics, Hair washing cosmetics, hair dyes, hair styling products, aromatic cosmetics, toothpaste, bath additives, antiperspirants, sunscreen products, suntan products, body powders, baby powders and other body cosmetics, shaving creams, pre-shave lotions, Examples include lotions such as aftershave lotion and body lotion.

In addition, ingredients commonly used in cosmetics can be added depending on the purpose, as long as the effects of the present invention are not impaired. Such ingredients include, for example, water, lower alcohols, oils and waxes, hydrocarbons, higher fatty acids, higher alcohols, sterols, fatty acid esters, metal soaps, humectants, surfactants, polymer compounds, color material raw materials, Examples include fragrances, preservatives/sterilizers, antioxidants, ultraviolet absorbers, and specially formulated ingredients.
Fats and waxes include avocado oil, almond oil, olive oil, cacao butter, beef tallow, sesame oil, wheat germ oil, safflower oil, shea butter, turtle oil, camellia oil, persic oil, castor oil, grape oil, macadamia nut oil, and mink oil. Oil, egg yolk oil, Japanese wax, coconut oil, rosehip oil, hydrogenated oil, silicone oil, orange roughy oil, carnauba wax, candelilla wax, spermaceti wax, jojoba oil, montan wax, beeswax, lanolin and the like.
Examples of hydrocarbons include liquid paraffin, vaseline, paraffin, ceresin, microcrystalline wax, squalane, and the like.
Examples of higher fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, behenic acid, undecylenic acid, oxystearic acid, linoleic acid, lanolin fatty acid, and synthetic fatty acids.

Higher alcohols include lauryl alcohol, cetyl alcohol, cetostearyl alcohol, stearyl alcohol, oleyl alcohol, behenyl alcohol, lanolin alcohol, hydrogenated lanolin alcohol, hexyldecanol, octyldecanol, isostearyl alcohol, jojoba alcohol, decyltetradeca Examples include Knoll and the like.
Examples of sterols include cholesterol, dihydrocholesterol, and phytocholesterol.
Fatty acid esters include ethyl linoleate, isopropyl myristate, isopropyl lanolin fatty acid, hexyl laurate, myristyl myristate, cetyl myristate, octyldodecyl myristate, decyl oleate, octyldodecyl oleate, hexadecyl dimethyloctanoate, isooctanoic acid. Cetyl, decyl palmitate, glyceryl trimyristate, tri(caprylic/capric) glycerin, propylene glycol dioleate, glyceryl triisostearate, glyceryl triisooctoate, cetyl lactate, myristyl lactate, diisostearyl malate and cholesteryl isostearate. , cyclic alcohol fatty acid esters such as cholesteryl 12-hydroxystearate.

Examples of the metal soap include zinc laurate, zinc myristate, magnesium myristate, zinc palmitate, zinc stearate, aluminum stearate, calcium stearate, magnesium stearate, zinc undecylenate, and the like.
Examples of humectants include glycerin, propylene glycol, 1,3-butylene glycol, polyethylene glycol, sodium dl-pyrrolidonecarboxylate, sodium lactate, sorbitol, sodium hyaluronate, polyglycerin, xylit, maltitol, and the like.
Examples of surfactants include higher fatty acid soaps, higher alcohol sulfates, N-acyl glutamates, anionic surfactants such as phosphate ester salts, cationic surfactants such as amine salts and quaternary ammonium salts, and betaine. type, amino acid type, imidazoline type, amphoteric surfactants such as lecithin, nonionic surfactants such as fatty acid monoglycerides, propylene glycol fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, polyglycerin fatty acid esters, and ethylene oxide condensates. Can be mentioned.

Examples of polymer compounds include natural polymer compounds such as gum arabic, gum tragacanth, guar gum, locust bean gum, gum karaya, iris moss, quince seed, gelatin, shellac, rosin, casein, sodium carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, Semi-synthetic polymer compounds such as sodium alginate, ester gum, nitrocellulose, hydroxypropylcellulose, crystalline cellulose, polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate, carboxyvinyl polymer, polyvinyl methyl ether, polyamide resin, silicone oil, nylon particles , synthetic polymer compounds such as resin particles such as polymethyl methacrylate particles, crosslinked polystyrene particles, silicone particles, urethane particles, and polyethylene particles.

Color material raw materials include iron oxide, ultramarine, konjou, chromium oxide, chromium hydroxide, carbon black, manganese violet, titanium oxide, zinc oxide, talc, kaolin, mica, calcium carbonate, magnesium carbonate, mica, aluminum silicate, Inorganic pigments such as barium silicate, calcium silicate, magnesium silicate, silica, zeolite, barium sulfate, calcined calcium sulfate (calcined gypsum), calcium phosphate, hydroxyapatite, ceramic powder, azo type, nitro type, nitroso type, xanthene type , quinoline-based, anthraquinoline-based, indigo-based, triphenylmethane-based, phthalocyanine-based, and pyrene-based tar pigments.

Here, the powder raw materials such as the above-mentioned polymer compounds and color material raw materials may be subjected to surface treatment in advance. As the surface treatment method, conventionally known surface treatment techniques can be used. For example, oil treatment with hydrocarbon oil, ester oil, lanolin, etc., silicone treatment with dimethylpolysiloxane, methylhydrogenpolysiloxane, methylphenylpolysiloxane, etc., perfluoroalkyl group-containing ester, perfluoroalkylsilane, perfluoropolyether , fluorine compound treatment with a polymer having a perfluoroalkyl group, silane coupling agent treatment with 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, etc., isopropyl triisostearoyl titanate, isopropyl tris ( Titanium coupling agent treatment with dioctyl pyrophosphate) titanate, etc., metal soap treatment, amino acid treatment with acylglutamic acid, etc., lecithin treatment with hydrogenated egg yolk lecithin, etc., collagen treatment, polyethylene treatment, moisture retention treatment, inorganic compound treatment, mechanochemical treatment Examples of processing methods include:

Examples of fragrances include natural fragrances such as lavender oil, peppermint oil, and lime oil, and synthetic fragrances such as ethyl phenylacetate, geraniol, and pt-butylcyclohexyl acetate.
Examples of preservatives and disinfectants include methylparaben, ethylparaben, propylparaben, benzalkonium, and benzethonium.
Examples of the antioxidant include dibutylhydroxytoluene, butylhydroxyanisole, propyl gallate, tocopherol, and the like.
Examples of ultraviolet absorbers include inorganic absorbers such as fine titanium oxide, fine zinc oxide, fine cerium oxide, fine iron oxide, and fine zirconium oxide, benzoic acid, para-aminobenzoic acid, anthranilic acid, salicylic acid, and cinnamic acid. Organic absorbents include benzophenone, dibenzoylmethane, and other organic absorbents.

Specially formulated ingredients include hormones such as estradiol, estrone, ethinyl estradiol, cortisone, hydrocortisone, and prednisone, vitamins such as vitamin A, vitamin B, vitamin C, and vitamin E, citric acid, tartaric acid, lactic acid, aluminum chloride, and sulfuric acid. Skin astringents such as aluminum/potassium, allantoin chlorhydroxyaluminum, zinc paraphenolsulfonate, zinc sulfate, cantharis tincture, capsicum tincture, ginger tincture, Japanese cabbage extract, garlic extract, hinokitiol, carpronium chloride, pentadecanoic acid glyceride, vitamins Examples include hair growth promoters such as E, estrogen, photosensitizer, and whitening agents such as magnesium phosphate-L-ascorbate and kojic acid.

(4-3-2) Paint, heat-insulating and light-diffusing composition, heat-insulating composition, and light-diffusing composition Paint, heat-insulating and light-diffusing composition, heat-insulating composition, and The light-diffusing composition includes a binder resin, a UV curable resin, a solvent, and the like, as necessary. As the binder resin, an organic solvent or water-soluble resin, or an emulsion-type aqueous resin that can be dispersed in water can be used.
The amounts of the binder resin or UV curable resin and organic-inorganic composite particles added also vary depending on the thickness of the coating film to be formed, the average particle diameter of the organic-inorganic composite particles, and the coating method. The amount of the organic-inorganic composite particles added is preferably 5 to 50% by weight based on the total of the binder resin (solid content when an emulsion type aqueous resin is used) and the organic-inorganic composite particles. A more preferable content is 10 to 50% by weight, and an even more preferable content is 20 to 40% by weight.
Examples of binder resins include acrylic resins, alkyd resins, polyester resins, polyurethane resins, chlorinated polyolefin resins, and amorphous polyolefin resins, and examples of UV-curable resins include polyhydric alcohol polyfunctional (meth)acrylates and the like. Functional (meth)acrylate resins; examples include polyfunctional urethane acrylate resins synthesized from diisocyanates, polyhydric alcohols, (meth)acrylic esters having hydroxyl groups, and the like.

As the UV curable resin, a polyfunctional (meth)acrylate resin is preferred, and a polyhydric alcohol polyfunctional (meth)acrylate resin having three or more (meth)acryloyl groups in one molecule is more preferred. Specifically, the polyhydric alcohol polyfunctional (meth)acrylate resin having three or more (meth)acryloyl groups in one molecule includes trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate , 1,2,4-cyclohexane tetra(meth)acrylate, pentaglycerol triacrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol Examples include tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol triacrylate, tripentaerythritol hexaacrylate, and the like, and they may be used alone or in combination of two or more.

When using a UV curable resin, a photopolymerization initiator is usually used together. The photopolymerization initiator is not particularly limited.
Examples of photopolymerization initiators include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, α-hydroxyalkylphenones, α-aminoalkylphenones, anthraquinones, thioxanthones, azo compounds, and peroxides. (described in JP-A No. 2001-139663, etc.), 2,3-dialkyldione compounds, disulfide compounds, fluoroamine compounds, aromatic sulfoniums, onium salts, borate salts, active halogen compounds, α-acyloxy Examples include muester and the like.
These binder resins or UV curable resins can be appropriately selected depending on the adhesion of the coating material to the substrate to be coated, the environment in which it is used, and the like.

The solvent is not particularly limited, but it is preferable to use a solvent that can dissolve or disperse the binder resin or UV curable resin. For example, for oil-based paints, hydrocarbon solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl acetate and butyl acetate; dioxane, ethylene glycol diethyl ether, and ethylene glycol. Examples include ether solvents such as monobutyl ether. If it is a water-based paint, water, alcohol, etc. can be used. These solvents may be used alone or in combination of two or more. The solvent content in the coating material is usually about 20 to 60% by weight based on the total amount of the composition.

The composition may contain known paint surface conditioners, fluidity conditioners, ultraviolet absorbers, light stabilizers, curing catalysts, extender pigments, coloring pigments, metal pigments, mica powder pigments, dyes, etc., as necessary. It may be
The method for forming a coating film using the composition is not particularly limited, and any known method can be used. For example, spray coating method, roll coating method, brush coating method, etc., and coating reverse roll coating method, gravure coating method, die coating method, comma coating method, spray coating method to coat a base material such as a film as a thin layer. can be mentioned. The composition may be diluted to adjust the viscosity as necessary. Diluents include hydrocarbon solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl acetate and butyl acetate; ether solvents such as dioxane and ethylene glycol diethyl ether; water. ; Examples include alcohol solvents. These diluents may be used alone or in combination of two or more.
A coating film can be formed by coating on an arbitrary coating surface such as a base material, drying this coating film, and then curing the coating film as necessary. The coating film using the coating composition can be used by coating various substrates, including metals, wood, glass, plastics, etc., but is not particularly limited. Moreover, it can also be used by coating a transparent substrate such as polyethylene terephthalate (hereinafter abbreviated as PET), polyethylene carbonate (hereinafter abbreviated as PC), or acrylic.

(4-3-3) Light diffusion film Light diffusion film is used for glass, polycarbonate, acrylic resin, PET, plastic sheets such as triacetyl cellulose (TAC), plastic films, plastic lenses, base materials such as plastic panels, and cathode ray tubes. , a light-diffusing layer made of the light-diffusing composition described above is formed on the surface of a base material such as a fluorescent display tube or a liquid crystal display board. Depending on the application, the coating may be used alone or on the base material as a protective film, hard coat film, flattening film, high refractive index film, insulating film, conductive resin film, conductive metal fine particle film, or conductive metal oxide fine particle. The film is formed in combination with a primer film, etc., which is used as necessary. Note that when used in combination, the light diffusion layer does not necessarily need to be formed on the outermost surface.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto. First, the measurement method in Examples will be explained.
(Hydrophobicity index of silica particles)
50 ml of ion-exchanged water was poured into a 100 ml glass beaker with a stirring bar placed at the bottom, and after 0.2 g of silica particles were floated on the water surface, the stirring bar was gently rotated. Thereafter, the tip of the burette was submerged in water near the center of the beaker, midway between the water surface and the bottom of the beaker, and while slowly rotating the stirrer, 5 minutes after the addition of the silica particles, 1 ml/ml of methanol was added from the burette. It was gradually introduced into the water at a rate of 1 minute. Methanol was introduced 1 ml at a time, and stirring was performed for 5 minutes each time 1 ml was introduced. Continue introducing methanol until the entire amount of silica particles on the water surface sinks into the water (until there are virtually no silica particles floating on the water surface), and calculate the amount of methanol introduced (ml) until the entire amount of particles sinks into the water. It was measured.
Then, the hydrophobicity index was determined based on the following formula from the amount of ion-exchanged water X (=50 (ml)) and the amount of methanol introduced Y (ml).
Hydrophobic index (%) = 100 x Y (ml) / (Y (ml) + X (ml))
Note that if the silica particles floating on the water surface completely sank into the water before methanol was introduced into the water from the buret, the hydrophobicity index was determined to be 0.

(Average particle size)
The average particle diameter (volume average particle diameter) of the particles was measured using Coulter Multisizer ^TM 3 (measurement device manufactured by Beckman Coulter). Measurements were performed using an aperture calibrated according to the Multisizer ^™ 3 User's Manual published by Beckman Coulter. In addition, when selecting the aperture used for measurement, if the assumed volume average particle diameter of the particles to be measured is 1 μm or more and 10 μm or less, select an aperture with a size of 50 μm; If the particle's expected volume average particle diameter is greater than 30 μm and 90 μm or less, select an aperture with a size of 100 μm; When the particle diameter was greater than 90 μm and less than 150 μm, an aperture having a size of 400 μm was selected, etc. as appropriate. If the volume average particle diameter after measurement was different from the expected volume average particle diameter, the aperture was changed to an appropriate size and the measurement was performed again.

Also, if you select an aperture with a size of 50 μm, Current (aperture current) is set to -800 and Gain (gain) is set to 4, and if you select an aperture with a size of 100 μm, Current (aperture current) is set to -800. 1600, Gain was set to 2, and when apertures having sizes of 280 μm and 400 μm were selected, Current (aperture current) was set to −3200, and Gain was set to 1.
As a sample for measurement, 0.1 g of particles was placed in 10 ml of a 0.1% by weight nonionic surfactant aqueous solution using a touch mixer ("TOUCHMIXER MT-31" manufactured by Yamato Kagaku Co., Ltd.) and an ultrasonic cleaner (Vervo Crea Co., Ltd.). A dispersion liquid was used. During the measurement, the inside of the beaker was gently stirred to prevent air bubbles from entering, and the measurement was terminated when 100,000 particles were measured. The volume average particle diameter of the particles was the arithmetic mean of the volume-based particle size distribution of 100,000 particles.

(Amount of inorganic components derived from inorganic particles in organic-inorganic composite particles)
After weighing 1.0 g of organic-inorganic composite particles, the weighed particles were evaporated in an electric furnace at 750° C. for 30 minutes, and the weight (g) of the remaining residue was measured. Then, the weight (g) of the measured residue is divided by the weight (g) of the particles before measurement, and the ignition residue (wt%) obtained by converting it into a percentage is the amount of ignition residue (% by weight) derived from the inorganic particles in the organic-inorganic composite particles. It was defined as the amount of inorganic components.

(Example 1)
254.1 g of methyl methacrylate (MMA) as a monofunctional monomer, 13.4 g of ethylene glycol dimethacrylate (EGDMA) as a crosslinking monomer, and hydrophilic fumed silica OX-50 (EVONIK) as an inorganic particle. , specific surface area 50 m ² /g by BET method, primary average particle diameter 40 nm, hydrophobicity index 0) 120 g, 3-methacryloxypropyltrimethoxysilane as a silicon-based compound (manufactured by Shin-Etsu Chemical Co., Ltd.; product name KBM-503) and 0.56 g of 2-methacryloyloxyethyl caproate acid phosphate (manufactured by Nippon Kayaku Co., Ltd.; product name PM-21) as an organic acid (acidic phosphate ester) were mixed, and the mixture was stirred at 30°C for 12 hours. . Thereafter, 1.40 g of 2,2'-azobis(2,4-dimethylvaleronitrile) (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.; product name V-65) as a polymerization initiator was mixed to form a polymerizable monomer. A polymeric composition was prepared.
On the other hand, 36.8 g of magnesium pyrophosphate was added as a suspension stabilizer to 1200 g of ion-exchanged water (aqueous medium) as an aqueous phase to obtain an aqueous dispersion medium.
The above polymerizable monomer composition was placed in an aqueous dispersion medium, and emulsified and dispersed for 5 minutes at a rotation speed of 7500 rpm using a homogenizer (manufactured by Central Kagaku Boeki Co., Ltd.; product name: Polytron Homogenizer PT10-35). and obtained an emulsion. The obtained emulsion was put into a 2 L pressure vessel equipped with a stirring blade, and polymerization was carried out at 50° C. for 4 hours while stirring with the stirring blade at 200 rpm. Furthermore, the temperature was raised to 105°C, and polymerization was continued for 1 hour.
Next, the mixture was cooled to room temperature, and hydrochloric acid was added to dissolve magnesium pyrophosphate. Next, after repeating solid-liquid separation and water washing, the particles were dried in a hot air dryer at 80° C. for 24 hours to obtain organic-inorganic composite particles. The volume average particle diameter of the obtained particles was 28.32 μm.
The amount of inorganic components (ignition residue) in the organic-inorganic composite particles was 31.3% by weight.

(Example 2)
Organic-inorganic composite particles were produced in the same manner as in Example 1, except that 0.56 g of lauryl phosphoric acid (manufactured by Nikko Chemicals, product name: Hosten HLP) was used instead of PM-21 as the organic acid. The volume average particle diameter of the obtained particles was 27.68 μm. The amount of inorganic components (ignition residue) in the organic-inorganic composite particles was 33.9% by weight.

(Example 3)
Same as Example 1 except that 0.56 g of polyoxyethylene alkyl (C8) ether phosphate ester (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.; product name Plysurf A208F) was used as the organic acid instead of PM-21. Organic-inorganic composite particles were prepared. The volume average particle diameter of the obtained particles was 43.0 μm. The amount of inorganic components (ignition residue) in the organic-inorganic composite particles was 33.0% by weight.

(Example 4)
Example 1, except that 0.56 g of polyoxyethylene alkyl (C12, C13) ether phosphate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; product name: Plysurf A208N) was used instead of PM-21 as the organic acid. Organic-inorganic composite particles were prepared in the same manner as above. The volume average particle diameter of the obtained particles was 17.21 μm. The amount of inorganic components (ignition residue) in the organic-inorganic composite particles was 32.9% by weight.

(Example 5)
Organic acid was prepared in the same manner as in Example 1, except that 0.56 g of polyoxyethylene lauryl ether phosphate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; product name: Plysurf A208B) was used instead of PM-21 as the organic acid. Inorganic composite particles were produced. The volume average particle diameter of the obtained particles was 16.82 μm. The amount of inorganic components (ignition residue) in the organic-inorganic composite particles was 34.1% by weight.

(Example 6)
Organic acid was prepared in the same manner as in Example 1, except that 0.56 g of polyoxyethylene lauryl ether phosphate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; product name: Plysurf A210D) was used instead of PM-21 as the organic acid. Inorganic composite particles were produced. The volume average particle diameter of the obtained particles was 26.18 μm. The amount of inorganic components (ignition residue) in the organic-inorganic composite particles was 32.9% by weight.

(Example 7)
An organic acid was prepared in the same manner as in Example 1, except that 0.56 g of polyoxyethylene lauryl ether phosphate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; product name Plysurf A219B) was used as the organic acid instead of PM-21. Inorganic composite particles were produced. The volume average particle diameter of the obtained particles was 27.5 μm. The amount of inorganic components (ignition residue) in the organic-inorganic composite particles was 33.1% by weight.

(Example 8)
Organic-inorganic composite particles were produced in the same manner as in Example 1, except that 19.6 parts by weight of PM-21 was used as the organic acid based on 100 parts by weight of the polymerizable monomer composition. The volume average particle diameter of the obtained particles was 20.07 μm. The amount of inorganic components (ignition residue) in the organic-inorganic composite particles was 37.7% by weight.

(Example 9)
Organic-inorganic composite particles were produced in the same manner as in Example 1, except that 36 parts by weight of KBM-503 as a silicon compound was used for 100 parts by weight of inorganic particles. The volume average particle diameter of the obtained particles was 24.8 μm. The amount of inorganic components (ignition residue) in the organic-inorganic composite particles was 34.3% by weight.

(Example 10)
An organic and inorganic compound was prepared in the same manner as in Example 1, except that KBM-503 was not used as the silicon compound and 12 g of hexyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.; product name KBM-3063) was used instead of KBM-503. Composite particles were produced. The volume average particle diameter of the obtained particles was 25.08 μm. The amount of inorganic components (ignition residue) in the organic-inorganic composite particles was 33.0% by weight.

(Example 11)
Organic-inorganic composite particles were produced in the same manner as in Example 1, except that EGDMA was not used as the crosslinking monomer and the amount of MMA, which was a monofunctional monomer, was 267.5 g. The volume average particle diameter of the obtained particles was 16.82 μm. The amount of inorganic components (ignition residue) in the organic-inorganic composite particles was 32.1% by weight.

(Example 12)
Organic-inorganic composite particles were produced in the same manner as in Example 2, except that EGDMA was not used as the crosslinking monomer and the amount of MMA, which was a monofunctional monomer, was 267.5 g. The volume average particle diameter of the obtained particles was 17.21 μm. The amount of inorganic components (ignition residue) in the organic-inorganic composite particles was 31.7% by weight.

(Comparative example 1)
A polymerizable monomer composition was obtained by carrying out the same composition and operation as in Example 1 except that the silicon-based compound of the polymerizable monomer composition of Example 1 was not added. In the obtained polymerizable monomer composition, the inorganic particles could not be appropriately dispersed, and the composition lost fluidity and could not be polymerized, so that organic-inorganic composite particles could not be obtained.

(Comparative example 2)
A polymerizable monomer composition was obtained by performing the same composition and operation as in Example 1 except that no organic acid was added. The obtained polymerizable monomer composition was unable to obtain organic-inorganic composite particles because the surface treatment of the inorganic particles with the silicon-based compound became slow and lost fluidity, making it impossible to perform polymerization. .

(Comparative example 3)
The same composition and operation as in Example 1 were carried out except that magnesium pyrophosphate was not used as a suspension stabilizer, but the polymerizable monomer composition could not be dispersed in the aqueous dispersion medium and the polymerization operation was impossible. Therefore, organic-inorganic composite particles could not be obtained.

A summary of Examples 1 to 12 and Comparative Examples 1 to 3 is shown in Table 1.

Claims (8)

a surface treatment step of treating the surface of the inorganic particles with a silicon-based compound and an organic acid in a polymerizable monomer in the absence of an organic solvent;
A polymerizable monomer composition containing surface-treated inorganic particles and a polymerizable monomer is suspended in an aqueous dispersion medium containing a suspension stabilizer, and the polymerizable monomer is polymerized to form organic and inorganic particles. a polymerization step to obtain composite particles ;
The polymerizable monomer is a vinyl monomer,
The inorganic particles are silica particles,
The silicon-based compound is a silane coupling agent,
Method for producing organic-inorganic composite particles. The method for producing organic-inorganic composite particles according to claim 1, wherein the organic acid is selected from phosphoric acid compounds, carboxylic acid compounds, and sulfonic acid compounds. The organic acid has the following general formula (I):
(In the formula, R ¹ is an alkyl group, vinyl group, allyl group, or (meth)acryloyl group having 1 to 20 carbon atoms, R ² is a divalent group derived from an alkane having 1 to 4 carbon atoms, and R ³ is a divalent group having 1 to 4 carbon atoms. -8 divalent group derived from an alkane, m is 0-30, n is 0-5, a is 1-3, b is greater than 0 and less than or equal to 2, and a+b is 3) The method for producing organic-inorganic composite particles according to claim 1 or 2. The method for producing organic-inorganic composite particles according to any one of claims 1 to 3, wherein the organic acid is used in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the polymerizable monomer composition. . According to any one of claims 1 to 4, wherein the inorganic particles are hydrophilic silica particles having a primary average particle size of 1 to 100 nm, and the organic-inorganic composite particles have a volume average particle size of 1 to 100 μm. The method for producing the organic-inorganic composite particles described above. The method for producing organic-inorganic composite particles according to any one of claims 1 to 5, wherein the inorganic particles are used in an amount of 15 to 200 parts by weight based on 100 parts by weight of the polymerizable monomer. The method for producing organic-inorganic composite particles according to any one of claims 1 to 6, wherein the silicon-based compound is used in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the inorganic particles. Any one of claims 1 to 7, wherein the suspension stabilizer is a poorly water-soluble inorganic compound, and is used in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the polymerizable monomer composition. The method for producing organic-inorganic composite particles described in .