WO2017038138A1

WO2017038138A1 - Composite particles, method for producing same, and use of same

Info

Publication number: WO2017038138A1
Application number: PCT/JP2016/060483
Authority: WO
Inventors: 俊貴竹中
Original assignee: 積水化成品工業株式会社
Priority date: 2015-08-31
Filing date: 2016-03-30
Publication date: 2017-03-09
Also published as: CN107949581A; JPWO2017038138A1; CN107949581B; JP6522135B2; KR102047656B1; KR20180048934A

Abstract

Provided are composite particles having affinity for water and, as a result, excellent dispersion stability in aqueous dispersion media such as aqueous binders, as well as excellent particle fluidity. The composite particles include polymer particles comprising a polymer of a vinyl monomer, and hydrophilic metal oxide particles adhered to the surface of the polymer particles, wherein the ratio of the calculated value (m²/g) of the specific surface area computed by the formula (calculated value of specific surface area) = 6/(ρ × Ｄ) from the volume-average particle diameter D (μm) and density ρ (g/cm³) of the composite particles, assuming the shape of the composite particles to be a true sphere, and the observed value (m²/g) of the specific surface area of the composite particles obtained by actual measurement (observed value of specific surface area)/(calculated value of specific surface area) is 1.20 or higher.

Description

COMPOSITE PARTICLE, PROCESS FOR PRODUCING THE SAME, AND USE THEREOF

The present invention relates to composite particles containing polymer particles and hydrophilic metal oxide particles attached to the surface of the polymer particles, a method for producing the same, and uses thereof (coating agent, optical film resin composition, molded product, And external preparations).

Polymer particles having an average particle size of 0.01 to 100 μm are, for example, additives for coating agents such as paints (matting agents, etc.), additives for inks (matting agents, etc.), and main components of adhesives. Or additives, additives for artificial marble (low shrinkage agents, etc.), paper treatment agents, packing materials for external agents such as cosmetics (fillers for improving slipperiness), column packing materials used for chromatography, static It is used in applications such as toner additives used for charge image development, anti-blocking agents for films, and light diffusing agents for light diffusers (such as light diffusing films).

By the way, in recent years, as one of methods for imparting new properties to polymer particles or improving the properties of polymer particles, composite polymer particles with hydrophilic metal oxide particles such as silica particles. Is considered. It is considered that the hydrophilicity of the particle surface can be improved by attaching hydrophilic metal oxide particles such as silica particles to the surface of the polymer particles. Since particles having hydrophilicity on the surface are easily dispersed in an aqueous medium, additives for water-based coating agents, for example, light diffusing agents used in water-based coating agents that form optical film coatings such as light diffusing films As, it can be used suitably.

Patent Document 1 discloses a method for producing composite particles including polymer particles and silica particles adhering to the polymer particles, in the presence of silica particles having water-soluble cellulose adsorbed on the surface. A method for producing composite particles is described which includes a polymerization step in which monomers are subjected to aqueous suspension polymerization to obtain composite particles.

In Comparative Example 4 of Patent Document 2, an emulsion obtained by absorbing a vinyl monomer containing a polymerization initiator in seed particles in an aqueous medium and colloidal silica are mixed, and the resulting mixture is obtained. A method for producing polymer particles in which the vinyl monomer is polymerized by heating is described.

International Publication No. 2015/071984 Japanese Patent No. 5281781

However, since the composite particles produced by the production method described in Patent Document 1 have relatively few surface irregularities derived from silica particles and the like, the surface irregularities derived from silica particles and the like significantly improve particle fluidity. As a result, there was room for improvement in particle fluidity (see Comparative Example 5 in the present specification). The improvement of the particle fluidity of the composite particles can be achieved by improving the handling properties of the composite particles when manufacturing products using the composite particles, such as optical films such as light diffusion films, and in aqueous dispersion media such as aqueous binders. This contributes to the suppression of the occurrence of buns (lumps formed by agglomeration of composite particles).

Further, according to the inventor of the present application, in the production method of Comparative Example 4 of Patent Document 2, silica particles contribute as a dispersant, but there is almost no adhesion to the surface of the polymer particles (the silica particles are not washed during washing). It was found that the polymer particles could not be given hydrophilicity and the fluidity of the polymer particles could not be improved (see Comparative Example 3 in the present specification).

The present invention has been made in view of such a situation, has hydrophilicity, and as a result, has excellent dispersion stability in an aqueous dispersion medium such as an aqueous binder, and also has excellent particle fluidity. It is an object of the present invention to provide composite particles, a production method thereof, and uses thereof.

The composite particle of the present invention is a composite particle comprising polymer particles composed of a polymer of a vinyl monomer, and hydrophilic metal oxide particles attached to the surface of the polymer particle, wherein the shape of the composite particle As a true sphere, the following formula (calculated value of specific surface area) = 6 / (ρ × D) from the volume average particle diameter D (μm) and density ρ (g / cm ³ ) of the composite particles
Ratio of the calculated specific surface area (m ² / g) calculated by the above and the actual measured specific surface area (m ² / g) of the composite particles obtained by actual measurement (measured specific surface area) / (Calculated value of specific surface area) is 1.20 or more.

The composite particles of the present invention have hydrophilicity due to the hydrophilicity of the hydrophilic metal oxide particles attached to the surface of the polymer particles, and as a result, are excellent in dispersion stability in an aqueous dispersion medium such as an aqueous binder. ing. The improvement of the dispersion stability in the aqueous dispersion medium contributes to, for example, suppression of defects generated in the coating (coating film) when the composite particles are mixed with an aqueous binder and used as a coating agent.

Also, the numerical value of (actual value of specific surface area) / (calculated value of specific surface area) represents how large the specific surface area is with respect to a true sphere, and thus represents the number of surface irregularities. The composite particles of the present invention have many surface irregularities because (actual value of specific surface area) / (calculated value of specific surface area) is 1.20 or more. Since the composite particles of the present invention have many surface irregularities, they are excellent in particle fluidity. The improvement of the particle fluidity of the composite particles can be achieved by improving the handling properties of the composite particles when manufacturing products using the composite particles, such as optical films such as light diffusion films, and in aqueous dispersion media such as aqueous binders. This contributes to the suppression of the generation of lumps (lumps formed by agglomeration of composite particles) and the formation of a good coating with a coating agent containing an aqueous binder.

The method for producing composite particles of the present invention is a method for producing composite particles comprising polymer particles composed of a polymer of a vinyl monomer, and hydrophilic metal oxide particles attached to the polymer particles, After the vinyl monomer is absorbed by the seed particles, the vinyl monomer is absorbed in an aqueous medium in the presence of hydrophilic metal oxide particles having water-soluble cellulose adsorbed on the surface and a reactive surfactant. It is characterized by including a polymerization step of obtaining composite particles by seed polymerization.

According to the above method, the vinyl monomer is polymerized in an aqueous medium in the presence of the hydrophilic metal oxide particles having water-soluble cellulose adsorbed on the surface, the water-soluble cellulose and the reactive surfactant. From the above, it is possible to improve the adhesion of the surface of the polymer particles during the polymerization by the action of the reactive surfactant, and to attach more hydrophilic metal oxide particles to the surface of the polymer particles, and to improve the hydrophilicity. The hydrophilic metal oxide particles can be firmly attached to the surface of the polymer particles by the action of the water-soluble celluloses adsorbed on the surface of the metal oxide particles. For this reason, the hydrophilic metal oxide particles attached to the surface of the polymer particles have hydrophilicity. As a result, they have excellent dispersion stability in an aqueous dispersion medium such as an aqueous binder, and hydrophilic metal oxide particles. Many surface irregularities derived from product particles, etc. (actual value of specific surface area) / (calculated value of specific surface area) are large (for example, 1.20 or more), so that particle fluidity is excellent, and from the surface of polymer particles Composite particles in which the hydrophilic metal oxide particles are difficult to fall off can be obtained.

Further, according to the above method, after the vinyl monomer is absorbed by the seed particles, the seed is obtained by polymerizing the vinyl monomer in an aqueous medium in a state in which the dispersion stability is improved by the reactive surfactant. Since composite particles are obtained by polymerization, composite particles having a smaller particle diameter variation coefficient (for example, 15% or less) and high particle diameter uniformity (monodispersity) can be obtained.

The coating agent of the present invention is characterized by containing the composite particles of the present invention.

Since the coating agent of the present invention contains the composite particles of the present invention, light diffusibility can be imparted to the coating (coating film) formed from the coating agent. In addition, when the coating agent contains an aqueous solvent, the coating agent may be spoiled due to the excellent particle fluidity of the composite particles and the hydrophilicity of the hydrophilic metal oxide particles attached to the surface of the polymer particles. Suppressed and good dispersibility of the composite particles can be obtained. Therefore, the coating agent can form a good coating.

The optical film of the present invention is an optical film including a base film and a coating formed thereon, and the coating includes the composite particles of the present invention.

Since the optical film of the present invention contains the composite particles of the present invention, it has light diffusibility.

According to the present invention, the composite particles have hydrophilicity, and as a result, are excellent in dispersion stability in an aqueous dispersion medium such as an aqueous binder, and are excellent in particle fluidity, a production method thereof, and the Applications can be provided.

2 is a scanning electron microscope (SEM) image showing the composite particles obtained in Example 1. FIG. 2 is a transmission electron microscope (TEM) image showing a cross section of the composite particles obtained in Example 1. FIG. 2 is a scanning electron microscope (SEM) image showing the composite particles obtained in Comparative Example 1. FIG. It is a figure which shows the infrared absorption spectrum of the extract of the composite particle obtained in Example 1 with the infrared absorption spectrum of hydroxypropyl methylcellulose.

Hereinafter, the present invention will be described in more detail.
[Composite particles]
The composite particle of the present invention is a composite particle comprising polymer particles composed of a polymer of a vinyl monomer, and hydrophilic metal oxide particles attached to the surface of the polymer particle, wherein the shape of the composite particle As a true sphere, the following formula (calculated value of specific surface area) = 6 / (ρ × D) from the volume average particle diameter D (μm) and density ρ (g / cm ³ ) of the composite particles
Ratio of the calculated specific surface area (m ² / g) calculated by the above and the actual measured specific surface area (m ² / g) of the composite particles obtained by actual measurement (measured specific surface area) / (Calculated value of specific surface area) is 1.20 or more.

The (actual value of specific surface area) / (calculated value of specific surface area) is more preferably 1.30 or more, further preferably 1.40 or more, and most preferably 1.50 or more. preferable. By these, the particle fluidity of the composite particles can be further improved. The (actual value of specific surface area) / (calculated value of specific surface area) is more preferably 50 or less, and further preferably 40 or less. Composite particles within these ranges are easy to manufacture.

In the composite particles of the present invention, the numerical value of the avalanche energy change AE (Avalanche Energy) before and after avalanche showing particle fluidity is preferably in the range of 10 to 50 kJ / kg. Thereby, composite particles with high particle fluidity can be realized.

The composite particle of the present invention has a particle diameter variation coefficient of 15% or less. Thereby, it is possible to realize composite particles having a highly uniform particle diameter.

The composite particles of the present invention preferably have a volume average particle diameter of 1 to 20 μm. Thereby, the composite particle suitable for uses, such as a coating agent, an optical film, a molded object, a resin composition, an external preparation, demonstrated in detail later, is realizable.

The composite particles of the present invention are preferably those in which at least a part of the polymer particles is coated with a layer composed of a plurality of silica particles.

(Vinyl monomer)
The polymer particles are a vinyl monomer polymer. The vinyl monomer is a compound having a group (ethylenically unsaturated group (broadly defined vinyl group)) containing a polymerizable carbon-carbon double bond (ethylenically unsaturated bond; broadly defined vinyl bond). .

The vinyl monomer may be a monofunctional vinyl monomer having an ethylenically unsaturated group (broadly defined vinyl group), and may have two or more ethylenically unsaturated groups (broadly defined vinyl group). It may be a vinyl monomer.

Examples of the monofunctional vinyl monomer include α-methylene aliphatic monocarboxylic acid ester; styrene; o-methyl styrene, m-methyl styrene, p-methyl styrene, p-ethyl styrene, 2,4-dimethyl. Styrene, pn-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene Derivatives of styrene such as p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene; vinyl carboxylates such as vinyl acetate, vinyl propionate, vinyl butyrate; acrylonitrile, acrylamide, etc. Acrylic acid derivatives other than acrylic esters; methacrylonitrile, methacrylate Methacrylic acid derivatives other than methacrylic acid esters such as Ruamido like.

Examples of the α-methylene aliphatic monocarboxylic acid ester include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, and 2-ethylhexyl acrylate. , Stearyl acrylate, lauryl acrylate, 2-chloroethyl acrylate, phenyl acrylate, 2- (dimethylamino) ethyl acrylate, 2- (diethylamino) ethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxy acrylate Acrylic esters such as propyl; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethyl methacrylate Methacrylic acid such as hexyl, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, 2- (dimethylamino) ethyl methacrylate, 2- (diethylamino) ethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate Esters: α-haloacrylic acid esters such as methyl α-chloroacrylate.

In some cases, α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid and the like can be used as a monofunctional vinyl monomer. Further, two or more of these may be used in combination. Also, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl compounds such as N-vinylpyrrolidone; vinyl naphthalene salts and the like can be used as a monofunctional vinyl monomer by combining one or more of them in a range not impeding the effects of the present invention.

In the present invention, the above monofunctional vinyl monomers may be used alone or in combination of two or more. Among the monofunctional vinyl monomers described above, styrene, methyl methacrylate, and the like are more preferable as the monofunctional vinyl monomers used in the present invention because they are inexpensive.

Examples of the polyfunctional vinyl monomer include divinylbenzene; ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate (repetition unit number: 2 to 10), propylene glycol di (meth) acrylate, polypropylene glycol di (Meth) acrylate (2-10 repeat units), 1,3-butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, alkoxylated neopentyl glycol di (meth) acrylate, propoxylated neopentyl Bifunctional alkylene glycol di (meth) acrylates such as glycol di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, dioxane glycol di (meth) acrylate; Range ol di (meth) acrylate, hexanediol di (meth) acrylate, alkoxylated hexanediol di (meth) acrylate, cyclohexanediol di (meth) acrylate, dodecanediol di (meth) acrylate, tricyclodecanediol di (meth) Bifunctional alkylene diol di (meth) acrylates such as acrylates; Bifunctional ethoxylated bisphenol A di (meth) acrylates such as ethoxylated (2-10 repeat units) bisphenol A di (meth) acrylates; Trifunctional trimethylo such as (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, triacryloyloxyethyl phosphate Propane tri (meth) acrylates; tetrafunctional tetra (meth) acrylates such as pentaerythritol tetra (meth) acrylate and ditrimethylolpropane tetra (meth) acrylate; hexafunctional dipentaerythritol hexa such as dipentaerythritol hexa (meth) acrylate (Meth) acrylates; octafunctional pentaerythritol (meth) acrylates such as poly (pentaerythritol) acrylate; trifunctional nitrogen atom-containing cyclic (meth) acrylates such as ethoxylated isocyanuric acid tri (meth) acrylate Can be mentioned. In this application document, “(meth) acrylate” means methacrylate or acrylate.

The vinyl monomer preferably includes both a monofunctional vinyl monomer and a polyfunctional vinyl monomer. Thereby, a favorable crosslinked structure can be formed in the polymer particles, and good solvent resistance can be imparted to the composite particles. The amount of the polyfunctional vinyl monomer used is preferably in the range of 0.5 to 50% by weight, preferably in the range of 1 to 40% by weight, based on the total amount of vinyl monomers used. More preferably. As a result, a better cross-linked structure can be formed in the polymer particles, and further excellent solvent resistance can be imparted to the composite particles.

(Hydrophilic metal oxide particles)
In the present application document, the term “hydrophilic metal oxide particles” means metal oxide particles that can be dispersed in water, and more specifically, takes hydrophilic behavior when introduced into water and stirred. By metal oxide particles, i.e. metal oxide particles dispersed in water whose surface is completely wetted by water and thus has a contact angle of less than 90 ° to water. Whether or not the metal oxide particles adhering to the surface of the polymer particles in the composite particles are hydrophilic is determined by whether or not the composite particles start to settle immediately as a result of the hydrophilicity test of the composite particles (see Examples). It can also be confirmed indirectly depending on whether or not. The hydrophilic metal oxide particle is not particularly limited as long as it is a metal oxide particle having hydrophilicity (having a number of hydroxyl groups to show hydrophilicity). Examples thereof include silica-coated metal oxide particles coated with metal oxide particles, composite oxide particles composed of at least one of tin oxide and zinc oxide doped with at least one of phosphorus and antimony, and the like.

As the silica particles, colloidal silica can be preferably used. Examples of the colloidal silica include powdered colloidal silica such as precipitated silica powder and gas phase method silica powder; colloidal silica sol stably dispersed to a primary particle level in a medium. Among these, colloidal silica sols stably dispersed to the primary particle level in a medium are more suitable for use in the production method of the present invention.

As the colloidal silica sol, an aqueous silica sol, an organosilica sol or the like can be preferably used. In particular, in the production method of the present invention, since the vinyl monomer is polymerized in an aqueous medium, it is most preferable to use aqueous colloidal silica from the viewpoint of dispersion stability of the colloidal silica sol. The silica concentration (solid content concentration) in the colloidal silica sol is preferably 5 to 50% by weight because it is generally commercially available and can be easily obtained.

Examples of commercially available colloidal silica include Snowtex (registered trademark) series manufactured by Nissan Chemical Industries, Ltd., for example, general-purpose type Snowtex (registered trademark) (alkaline, which is spherical particles having an average primary particle size of 5 to 100 nm). : "ST-XS", "ST-30", "ST-50", "ST-30L", "ST-ZL", acidic: "ST-OXS", "ST-O", "ST-O-" 40 ”,“ ST-OL ”,“ ST-OZL35 ”), large-sized SNOWTEX® (alkaline:“ ST-MP-2040 ”,“ Spherical particles having an average primary particle diameter of 70 to 480 nm ”,“ ST-MP-4540M "), a chain-type Snowtex (registered trademark) having an average primary particle diameter of 40 to 100 nm (alkaline:" ST-UP ", acidic: ST-OUP "), Snowtex (registered trademark) of a pearl necklace type in which spherical particles having an average primary particle diameter of 10 to 25 nm are connected (alkalinity:" ST-PS-S "," ST-PS-M ", Acidity: “ST-PS-SO”, “ST-PS-MO”) and the like.

When silica-coated metal oxide particles are used as the hydrophilic metal oxide particles, especially when the metal oxide other than silica is a metal oxide having high photocatalytic activity such as titanium oxide or zinc oxide. Silica coating the metal oxide particles other than silica inactivates the photocatalytic activity of the metal oxide other than silica, so that the metal oxide other than silica and other components deteriorate due to photocatalytic reaction by ultraviolet rays (for example, yellow Can be effectively suppressed. As a result, the weather resistance of the composite particles and products using the same can be effectively improved.

The silica content in the silica-coated metal oxide particles is preferably 10% by weight or more. When the silica content in the silica-coated metal oxide particles is less than 10% by weight, the effect of suppressing deterioration (for example, yellowing) of composite particles of silica and products using the silica by ultraviolet rays becomes small. The silica content in the silica-coated metal oxide particles is more preferably 10% by weight or more and 50% by weight or less. When the silica content in the silica-coated metal oxide particles is more than 50% by weight, the imparting of characteristics (for example, ultraviolet shielding characteristics) to the composite particles by the metal oxide other than silica is not remarkable.

Examples of the metal oxide other than silica constituting the silica-coated metal oxide particles include titanium oxide, zinc oxide, cerium oxide, iron oxide, zirconium oxide and the like, and at least one of titanium oxide and zinc oxide is preferable. When the metal oxide other than silica is at least one of titanium oxide and zinc oxide, excellent ultraviolet shielding properties can be imparted to the composite particles, and it can be suitably used for external preparations such as light diffusion plates and cosmetics. In addition, titanium oxide and zinc oxide have high photocatalytic activity. However, in the composite particles of the present invention, titanium oxide, zinc oxide, and other components are contained by inactivating the photocatalytic activity of titanium oxide and zinc oxide. Deterioration (for example, yellowing) due to a photocatalytic reaction by ultraviolet rays can be effectively suppressed. As a result, it is possible to improve the weather resistance of composite particles containing at least one of titanium oxide and zinc oxide as metal oxides other than silica and products using the same.

The silica-coated metal oxide particles are at least one of silica-coated titanium oxide particles in which titanium oxide particles are coated with silica and silica-coated zinc oxide particles in which zinc oxide particles are coated with silica. preferable. As the silica-coated titanium oxide particles, commercially available products of silica-coated titanium oxide particles or an aqueous dispersion thereof can be used. Examples of commercially available silica-coated titanium oxide particles or aqueous dispersions thereof include “Maxlite (registered trademark) TS-01”, “Maxlite (registered trademark) TS-04”, and “Maxlite (registered trademark)”. “TS-043”, “Maxlite (registered trademark) F-TS20” (manufactured by Showa Denko KK), “MT-100HP”, “MT-100WP”, “MT-500SA”, “WT-PF01” ( (Water dispersion with a solid content of 40 wt%) (above, manufactured by Teika Co., Ltd.), “STR-100A”, “STR-100W”, “GT-10W” (water dispersion with a solid content of 40 wt%) (above, 堺Chemical Industry Co., Ltd.), “ST-455WS” (Titanium Industry Co., Ltd.) and the like.

As the silica-coated zinc oxide particles, commercially available products of silica-coated zinc oxide particles can be used. Examples of commercially available silica-coated zinc oxide particles include “Maxlite (registered trademark) ZS-032”, “Maxlite (registered trademark) ZS-032-D” (above, Showa Denko KK), “ FINEX (registered trademark) -30W "," FINEX (registered trademark) -50W "(manufactured by Sakai Chemical Industry Co., Ltd.), and the like.

Examples of the composite oxide particles composed of at least one of tin oxide and zinc oxide doped with at least one of phosphorus and antimony include, for example, tin oxide (phosphorus-doped tin oxide) particles doped with phosphorus, and doped with antimony. And zinc oxide particles, and mixtures thereof. Since the substance containing antimony has a concern about environmental burden, the composite oxide particle may be composed of at least one of tin oxide doped with phosphorus and zinc oxide (for example, tin oxide doped with phosphorus). More preferred. Examples of commercially available tin oxide (phosphorus-doped tin oxide) particles doped with phosphorus include “Cellnax (registered trademark) CX-S301H” (aqueous dispersion, manufactured by Nissan Chemical Industries, Ltd.). Examples of the zinc oxide particles doped with antimony include “Selnax (registered trademark) CX-Z330H” (aqueous dispersion, manufactured by Nissan Chemical Industries, Ltd.).

The average primary particle diameter of the hydrophilic metal oxide particles is preferably in the range of 5 to 200 nm. If the average primary particle diameter is larger than 200 nm, the dispersion stability during the production of the composite particles is lowered, which is not preferable. The average primary particle size of the hydrophilic metal oxide particles is preferably as small as possible, more preferably in the range of 5 to 150 nm, and still more preferably in the range of 8 to 100 nm.

The density (specific gravity) of the hydrophilic metal oxide particles is preferably in the range of 1.5 to 10.0 g / cm ³ . When the density is higher than 10.0 g / cm ³ , the dispersion stability during production of the composite particles is lowered, which is not preferable.

Further, the content of the hydrophilic metal oxide particles in the composite particles of the present invention is not particularly limited, but is preferably in the range of 0.5 to 10% by weight. Thereby, the hydrophilicity of the composite particles can be further improved, and the particle fluidity can be further improved by further increasing (actual value of specific surface area) / (calculated value of specific surface area).

(Water-soluble celluloses)
The composite particles of the present invention preferably further contain water-soluble celluloses. In this case, since the hydrophilic metal oxide particles are firmly attached to the surface of the polymer particles due to the inclusion of the water-soluble celluloses, the hydrophilic metal oxide particles are difficult to fall off from the surface of the polymer particles.

In the composite particles further containing water-soluble celluloses, the hydrophilic metal oxide particles may be attached to the surface of the polymer particles via the water-soluble celluloses, or on the surface of the polymer particles. It may be attached directly. In other words, the water-soluble celluloses may be attached to both the hydrophilic metal oxide particles and the polymer particles, or only to one of the hydrophilic metal oxide particles and the polymer particles. You may do it.

The water-soluble cellulose is not particularly limited, and examples thereof include alkyl celluloses such as methyl cellulose; hydroxyalkyl celluloses such as hydroxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose; hydroxyalkylalkyl such as hydroxyethyl methyl cellulose and hydroxypropyl methyl cellulose. Compounds such as celluloses are listed. Among these compounds, hydroxyalkylcelluloses and hydroxyalkylalkylcelluloses are preferable, and hydroxypropylcellulose (HPC) and hydroxypropylmethylcellulose (HPMC) are more preferable. These compounds may be used alone or in combination of two or more.

Hydroxypropyl cellulose (HPC) is generally known to have a lower critical solution temperature (LCST) of 45 ° C., and commercially available products include, for example, NISSO (registered trademark) manufactured by Nippon Soda Co., Ltd. The HPC series (“SSL”, “SL”, “L”, “M”, “H”, etc.) can be mentioned.

Moreover, as a commercial item of hydroxypropyl methylcellulose (HPMC), Shin-Etsu Chemical Co., Ltd.'s Metroles (registered trademark) series, more specifically, Metrows (registered trademark) 60SH series having a cloud point of 60 ° C. (“ SH60-50 ”,“ 60SH-4000 ”,“ 60SH-10000 ”), and Metrows (registered trademark) 65SH series (“ 65SH-50 ”,“ 65SH-400 ”,“ 65SH-1500 ”) having a cloud point of 65 ° C. , “65SH-4000”), Metroles (registered trademark) 90SH series having a cloud point of 90 ° C. (“90SH-100”, “90SH-400”, “90SH-4000”, “90SH-15000”), etc. be able to.

[Production method of composite particles]
The method for producing composite particles of the present invention is a method for producing composite particles comprising polymer particles composed of a polymer of a vinyl monomer, and hydrophilic metal oxide particles attached to the polymer particles, After the vinyl monomer is absorbed by the seed particles, the vinyl monomer is absorbed in an aqueous medium in the presence of hydrophilic metal oxide particles having water-soluble cellulose adsorbed on the surface and a reactive surfactant. A polymerization step for obtaining composite particles by seed polymerization is included.

(Hydrophilic metal oxide particles with water-soluble cellulose adsorbed on the surface)
The amount of the water-soluble cellulose adsorbed on the hydrophilic metal oxide particles is not particularly limited and can be appropriately set according to the specific surface area of the hydrophilic metal oxide particles used in the present invention. The amount is preferably 0.05 g to 0.5 g per 1 g of the hydrophilic metal oxide particles.

The amount of water-soluble cellulose adsorbed on the hydrophilic metal oxide particles can be determined, for example, by the Journal of Polymer Science and Technology published by the Polymer Society of Japan (Japan Society of Polymer Science and Technology) Vol. 40, no. 10, pp. It can be measured using the method described in 697-702 (Oct, 1983). For example, it can be measured by [Method for measuring the amount of water-soluble cellulose adsorbed on hydrophilic metal oxide particles] described in the Examples section below.

In the production method of the present invention, before the polymerization step, the hydrophilic metal oxide particles are treated with the water-soluble celluloses to adsorb the water-soluble celluloses on the surfaces of the hydrophilic metal oxide particles. It is preferable to include an adsorption step.

A method for treating the hydrophilic metal oxide particles with the water-soluble celluloses for adsorbing the water-soluble celluloses on the surface of the hydrophilic metal oxide particles is not particularly limited, and a known method is applied. For example, a method in which hydrophilic metal oxide particles and water-soluble celluloses coexist in an aqueous medium, and water-soluble celluloses are physically adsorbed on the surface of the hydrophilic metal oxide particles (as a specific example) Is Rheological and Interface Properties of Silicone Oil Emulsions Prepared by Polymer Pre-adsorbed onto Silica Particles, Colloids Surfaces: Eng.Aspects, 328,2008,114-122 method described in. The literature) are preferred. The water-soluble celluloses adsorbed on the hydrophilic metal oxide particles by this treatment method are in a stable state with almost no desorption from the hydrophilic metal oxide particles in the polymerization step.

Further, under the temperature condition above (T-15) ° C. of the water-soluble cellulose (T means the lower critical solution temperature (° C.) or cloud point (° C.) of the water-soluble cellulose). Preferably, the hydrophilic metal oxide particles and the water-soluble cellulose are allowed to coexist under a temperature condition of (T-15) ° C. or higher and (T + 20) ° C. or lower, so that the hydrophilic metal is more effectively used. Water-soluble celluloses can be physically adsorbed on the surface of the oxide particles. In addition, the said water-soluble cellulose has only one of a lower critical solution temperature or a cloud point by the characteristic.

In the adsorption step, water-soluble celluloses that are not adsorbed on the hydrophilic metal oxide particles may be removed by centrifugation or the like before the polymerization step, or obtained in the polymerization step after the polymerization step. You may remove by washing | cleaning in the refinement | purification process which refine | purifies the obtained composite particle.

(Reactive surfactant)
Examples of the reactive surfactant include any of anionic reactive surfactants, cationic reactive surfactants, zwitterionic reactive surfactants, and nonionic reactive surfactants. Although it can be used, it is preferable to use a nonionic reactive surfactant. When an anionic reactive surfactant is used as the reactive surfactant, the reactive surfactant contains metal ions such as sodium ions, so that aggregation of hydrophilic metal oxide particles is likely to occur. As a result, the dispersion stability of the composite particles may decrease, and the uniformity of the particle diameter of the composite particles may decrease. When a nonionic type reactive surfactant is used as the reactive surfactant, the reactive surfactant does not contain metal ions, so that the aggregation of hydrophilic metal oxide particles hardly occurs. As a result, the dispersion stability of the composite particles can be improved, and the uniformity of the particle diameter of the composite particles can be improved.

Examples of the nonionic reactive surfactant include Adekaria Soap (registered trademark) ER-10 (100% pure) by Adeka Co., Ltd., Adekaria Soap (registered trademark) ER-20 (pure component). 75% by weight), Adekalia Soap (registered trademark) ER-30 (pure content 65% by weight, Adekalia Soap (registered trademark) ER-40 (pure content 60% by weight), Adekalia soap (registered trademark) NE-10 (100% by weight pure), Adekaria Soap (registered trademark) NE-20 (80% by weight pure), Adekaria Soap (registered trademark) NE-30 (80% by weight pure), and Adekaria Soap (registered) Trademark) NE-40 (pure content 40% by weight); Aqualon (registered trademark) RN-20 (pure content 10) which is polyoxyethylene nonylpropenyl phenyl ether manufactured by Daiichi Kogyo Seiyaku Co., Ltd. %), Aqualon (registered trademark) RN-2025 (25% pure), Aqualon (registered trademark) RN-30 (100% pure), and Aqualon (registered trademark) RN-50 (65% pure) %); LATEMUL (registered trademark) PD-420 (100% by weight pure), LATEMUL (registered trademark) PD-430 (100% by weight pure), (Registered trademark) PD-450 (pure content: 100% by weight), etc. The reactive surfactants may be used alone or in combination of two or more.

The type of the reactive surfactant is appropriately selected in consideration of the diameter of the obtained composite particles, the dispersion stability of the vinyl monomer at the time of polymerization, and the amount used is appropriately adjusted. The amount of the reactive surfactant used is preferably in the range of 0.01 to 5 parts by weight, preferably in the range of 0.1 to 2.0 parts by weight, with respect to 100 parts by weight of the vinyl monomer. More preferably, it is within. When the amount of the reactive surfactant used is less than the above range, the polymerization stability may be lowered. Moreover, when there are more usage-amounts of a reactive surfactant than the said range, the cost for a reactive surfactant will deteriorate.

(Non-reactive surfactant)
In the polymerization step of the production method of the present invention, the polymerization of the vinyl monomer in the aqueous medium may be performed in the presence of a non-reactive surfactant in order to further improve the dispersion stability. . Examples of the non-reactive surfactant include an anionic non-reactive surfactant, a cationic non-reactive surfactant, a zwitterionic non-reactive surfactant, and a nonionic non-reactive surfactant. Any non-reactive surfactant can be used as the non-reactive surfactant, particularly when a non-ionic reactive surfactant is used as the reactive surfactant. It is preferable to use it.

Examples of the anionic non-reactive surfactant-sensitive surfactant include sodium oleate; fatty acid soap such as castor oil potash soap; alkyl sulfate ester salt such as sodium lauryl sulfate and ammonium lauryl sulfate; sodium dodecylbenzenesulfonate Alkyl benzene sulfonates; alkyl naphthalene sulfonates; alkane sulfonates; dialkyl sulfosuccinates such as sodium dioctyl sulfosuccinate; alkyl phosphate ester salts; naphthalene sulfonic acid formalin condensates; polyoxyethylene alkyl phenyl ether sulfates Salt; polyoxyethylene alkyl sulfate salt and the like.

Nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin Examples include fatty acid esters and oxyethylene-oxypropylene block polymers.

Examples of the cationic non-reactive surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate; quaternary ammonium salts such as lauryltrimethylammonium chloride.

Examples of zwitterionic non-reactive surfactants include lauryl dimethylamine oxide, phosphate ester surfactants, phosphite ester surfactants, and the like. These non-reactive surfactants may be used alone or in combination of two or more.

The type of the non-reactive surfactant is appropriately selected in consideration of the diameter of the resulting composite particles, the dispersion stability of the vinyl monomer at the time of polymerization, and the amount used is appropriately adjusted. The amount of the non-reactive surfactant used is preferably in the range of 0.01 to 5 parts by weight with respect to 100 parts by weight of the vinyl monomer. When the amount of the non-reactive surfactant used is less than the above range, the polymerization stability may be lowered. Moreover, when the usage-amount of a non-reactive surfactant is more than the said range, the cost for a non-reactive surfactant will deteriorate.

(Aqueous medium)
Examples of the aqueous medium used in the polymerization step of the production method of the present invention include water or a mixed medium of water and a water-soluble medium (for example, alcohol such as methanol and ethanol). In order to stabilize the composite particles, the amount of the aqueous medium used is usually preferably 100 to 1000 parts by weight with respect to 100 parts by weight of the vinyl monomer used.

(Polymerization initiator)
In the polymerization step of the production method of the present invention, the polymerization of the vinyl monomer in the aqueous medium is preferably performed in the presence of a polymerization initiator.

As the polymerization initiator, an oil-soluble peroxide-based polymerization initiator or azo-based polymerization initiator usually used for polymerization in an aqueous medium can be suitably used.

Examples of the peroxide-based polymerization initiator include benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, cumene hydroperoxide. Cyclohexanone peroxide, t-butyl hydroperoxide, diisopropylbenzene hydroperoxide and the like.

Examples of the azo polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2,3- Dimethylbutyronitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2,3,3-trimethylbutyronitrile), 2,2′-azobis (2-isopropyl) Butyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), (2-carbamoylazo) isobutyronitrile 4,4′-azobis (4-cyanovaleric acid), dimethyl-2,2′-azobisisobutyrate and the like.

Among the above polymerization initiators, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), benzoyl peroxide, peroxide are used from the viewpoint of decomposition rate and the like. Lauroyl or the like is preferable as a polymerization initiator that can be used in the production method of the present invention.

The amount of the polymerization initiator used is preferably 0.01 to 10 parts by weight and preferably 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the vinyl monomer used. Is more preferable. When the amount of the polymerization initiator used is less than 0.01 parts by weight with respect to 100 parts by weight of the vinyl monomer used, it is difficult to sufficiently perform the polymerization initiation function, and 10 parts by weight. Exceeding this is not preferable because an effect commensurate with the amount of use cannot be obtained and the cost is uneconomical.

The polymerization initiator may be mixed with a vinyl monomer, and then the resulting mixture may be dispersed in an aqueous medium, or both the polymerization initiator and the vinyl monomer may be separately aqueous. You may mix what was disperse | distributed to the medium.

(Polymerization inhibitor)
In the polymerization step of the production method of the present invention, the polymerization of the vinyl monomer in the aqueous medium is water-soluble in order to suppress the generation of emulsified particles (polymer particles having a too small particle diameter) in the aqueous system. The polymerization may be carried out in the presence of a polymerization inhibitor.

Examples of the water-soluble polymerization inhibitor include nitrites, sulfites, hydroquinones, ascorbic acids, water-soluble vitamin Bs, citric acid, and polyphenols. The addition amount of the polymerization inhibitor is preferably in the range of 0.02 to 0.2 parts by weight with respect to 100 parts by weight of the vinyl monomer for seed polymerization.

(Other additives)
In the polymerization step of the production method of the present invention, other additives such as pigments, dyes, antioxidants, and the like, as long as the polymerization of the vinyl monomer in the aqueous medium does not interfere with the effects of the present invention. It may be carried out in the presence of an ultraviolet absorber or the like.

Examples of the pigment include inorganic pigments such as lead white, red lead, yellow lead, carbon black, ultramarine, zinc oxide, cobalt oxide, titanium dioxide, iron oxide, titanium yellow, and titanium black; Navels Yellow, Naphthol Yellow S , Yellow pigments such as Hansa Yellow 10G, Benzidine Yellow G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake; Orange Pigments such as Molybdenum Orange, Permanent Orange RK, Benzidine Orange G, Indanthrene Brilliant Orange GK Permanent red 4R, risor red, pyrazolone, red 4R, watching red calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake, briri Red pigments such as Toccarmin B; Purple pigments such as Fast Violet B, Methyl Violet Lake, Dioxane Violet; Alkaline Blue Lake, Victoria Blue Lake, Phthalocyanine Blue, Metal-free Phthalocyanine Blue, Phthalocyanine Blue Partial Chloride; Fast Sky Blue, Indance Blue pigments such as Ren Blue BC; Green pigments such as Pigment Green B, Malachite Green Lake, and Fanal Yellow Green G; Isoindolinone pigments, quinacridone pigments, perinone pigments, perylene pigments, insoluble azo pigments, soluble azo pigments, dye lakes Organic pigments such as pigments can be mentioned.

Examples of the dye include a nitroso dye, a nitro dye, an azo dye, a stilbene azo dye, a diphenylmethane dye, a triphenylmethane dye, a xanthene dye, an acridine dye, a quinoline dye, a methine dye, a polymethine dye, a thiazole dye, an indamine dye, and an Indian dye. A phenol dye, an azine dye, an oxazine dye, a thiazine dye, a sulfur dye, etc. can be mentioned.

Examples of the antioxidant include 2,6-di-t-butyl-4-methylphenol (BHT), n-octadecyl-3 ′-(3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) ) Propionate, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,3,5-tris (3,5-di-tert-butyl-4- Hydroxybenzyl) isocyanurate, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 3,9-bis [2- {3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane Distearyl pentaerythritol diphosphite, tris (2,4-di-t-butylphenyl) phosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, Tetrakis (2,4-di-t-butylphenyl) 4,4′-biphenylenediphosphonite, bis (2-t-butyl-4-methylphenyl) pentaerythritol diphosphite, 2,4,8,10 -Tetra-t-butyl-6- [3- (3-methyl-4-hydroxy-5-t-butylphenyl) propoxy] dibenzo [d, f] [1,3,2] dioxaphosphine Phosphorous antioxidants; phenyl-1-naphthylamine, octylated diphenylamine, 4,4-bis (α, α-dimethylbenzyl) diphenylami , Mention may be made of N, N'-di-2-naphthyl -p- amine antioxidants such as phenylenediamine.

Examples of the ultraviolet absorber include benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers (for example, “ADEKA STAB (registered trademark) LA-31” manufactured by ADEKA Corporation), hydroxyphenyltriazine ultraviolet absorbers, and the like. .

(Method of polymerization)
In seed polymerization, seed particles are added to an emulsion containing the vinyl monomer and an aqueous medium. The emulsion can be prepared by a known method. For example, a vinyl monomer and a reactive surfactant (and a non-reactive surfactant) are added to an aqueous medium and dispersed by a fine emulsifier such as a homogenizer, an ultrasonic processor, or a nanomizer (registered trademark). Thus, an emulsion can be obtained.

The seed particles may be added to the emulsion as it is, or may be added to the emulsion in a form dispersed in an aqueous medium. After the seed particles are added to the emulsion, the vinyl monomer is absorbed by the seed particles. This absorption can usually be performed by stirring the emulsion at room temperature (about 20 ° C.) for 1 to 12 hours. Further, the emulsion may be heated to about 30 to 50 ° C. in order to promote the absorption of the vinyl monomer into the seed particles.

The seed particles swell by absorbing the vinyl monomer. The mixing ratio of the vinyl monomer to the seed particles is preferably within the range of 5 to 300 parts by weight of the vinyl monomer for seed polymerization with respect to 1 part by weight of the seed particles. More preferably within the range of 250 parts by weight. When the mixing ratio of the vinyl monomer is smaller than the above range, the increase in particle diameter due to polymerization is small, and thus the production efficiency is lowered. On the other hand, if the mixing ratio of the vinyl monomer for seed polymerization to be absorbed is larger than the above range, the vinyl monomer for seed polymerization is not completely absorbed by the seed particles and is uniquely emulsion polymerized in an aqueous medium. As a result, polymer particles having an abnormally small particle size may be produced. The end of absorption of the vinyl monomer into the seed particles can be determined by confirming the expansion of the particle diameter by observation with an optical microscope.

If the particle size of the vinyl monomer droplets in the resulting emulsion is smaller than the particle size of the seed particles, the vinyl monomer is more efficiently absorbed by the seed particles. Therefore, it is preferable.

And the composite particle | grains which concern on this invention can be obtained by polymerizing the vinyl-type monomer absorbed by the seed particle.

The polymerization temperature of the seed polymerization can be appropriately determined according to the type of vinyl monomer and the type of polymerization initiator used as necessary. Specifically, the polymerization temperature of the seed polymerization is preferably 25 to 110 ° C., more preferably 50 to 100 ° C. The polymerization time for seed polymerization is preferably 1 to 12 hours. The polymerization reaction of the seed polymerization may be performed in an atmosphere of an inert gas (for example, nitrogen) that is inert to the polymerization. In addition, it is preferable that the polymerization reaction of seed polymerization is performed by raising the temperature after the vinyl monomer and the polymerization initiator used as necessary are completely absorbed by the seed particles.

In the seed polymerization, a polymer dispersion stabilizer may be added to the polymerization reaction system in order to improve the dispersion stability of the polymer particles. Examples of the polymer dispersion stabilizer include polyvinyl alcohol, polycarboxylic acid, celluloses (such as hydroxyethyl cellulose and carboxymethyl cellulose), and polyvinylpyrrolidone. Moreover, the polymer dispersion stabilizer and an inorganic water-soluble polymer compound such as sodium tripolyphosphate may be used in combination. Of these polymer dispersion stabilizers, polyvinyl alcohol and polyvinyl pyrrolidone are preferred. The addition amount of the polymer dispersion stabilizer is preferably in the range of 1 to 10 parts by weight with respect to 100 parts by weight of the vinyl monomer.

In this way, the composite particles obtained by polymerizing the vinyl monomer absorbed by the seed particles are removed from the aqueous medium by filtration, centrifugation, or the like as necessary after the polymerization is completed. After being washed with a solvent, it is dried and isolated. The drying method is not particularly limited. For example, a spray drying method typified by a spray dryer, a method of drying by adhering to a heated rotating drum typified by a drum dryer, a freeze drying method, etc. Is mentioned.

(Seed particles)
The seed particles are a polymer of a vinyl monomer for seed particles. The vinyl monomer for seed particles may be the same as or different from the vinyl monomer used for seed polymerization.

The polymerization method for polymerizing the vinyl monomer for seed particles to obtain seed particles is not particularly limited, but dispersion polymerization, emulsion polymerization, soap-free emulsion polymerization, seed polymerization, suspension polymerization. Etc. can be used. In order to obtain polymer particles having a substantially uniform particle size by seed polymerization, it is first necessary to use seed particles having a substantially uniform particle size and grow these seed particles substantially uniformly. Seed particles with a substantially uniform particle size as a raw material are produced by polymerizing vinyl monomers for seed particles using polymerization methods such as soap-free emulsion polymerization (emulsion polymerization without using a surfactant) and dispersion polymerization. can do. Therefore, as a polymerization method for obtaining seed particles, emulsion polymerization, soap-free emulsion polymerization, seed polymerization, and dispersion polymerization are preferable.

In the polymerization of the vinyl monomer for seed particles to obtain seed particles, a polymerization initiator is used as necessary. Examples of the polymerization initiator include persulfates such as potassium persulfate, ammonium persulfate, sodium persulfate, and potassium peroxodisulfate; benzoyl peroxide, lauroyl peroxide, o-chlorobenzoic peroxide, o-methoxyperoxide. Organic peroxides such as benzoyl, 3,5,5-trimethylhexanoyl peroxide, tert-butylperoxy-2-ethylhexanoate, di-tert-butyl peroxide; 2,2′-azobisisobuty And azo compounds such as rhonitrile, 1,1′-azobiscyclohexanecarbonitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), and the like. The polymerization initiator is preferably used in an amount of 0.1 to 3 parts by weight with respect to 100 parts by weight of the vinyl monomer for seed polymerization. The weight average molecular weight of the obtained seed particles can be adjusted by adjusting the amount of the polymerization initiator used.

In the polymerization for obtaining seed particles, a molecular weight modifier may be used in order to adjust the weight average molecular weight of the obtained seed particles. Examples of the molecular weight modifier include mercaptans such as n-octyl mercaptan and tert-dodecyl mercaptan; α-methylstyrene dimer; terpenes such as γ-terpinene and dipentene; halogenated hydrocarbons such as chloroform and carbon tetrachloride, etc. Can be used. The weight average molecular weight of the obtained seed particles can be adjusted by adjusting the amount of the molecular weight modifier used.

The seed particle is used as a primary seed particle, and after the vinyl monomer is absorbed by the primary seed particle, seed polymerization is performed once or a plurality of times to polymerize the vinyl monomer in an aqueous medium. It may be seed particles obtained by performing (secondary seed particles when obtained by performing seed polymerization once). This seed polymerization is the same as the seed polymerization for obtaining composite particles, except that hydrophilic metal oxide particles, water-soluble celluloses and a reactive surfactant are not required.

〔Coating agent〕
The composite particles of the present invention can be contained in a coating agent as a coating film (coating) softening agent, a matting agent for paint, a light diffusing agent, or the like. The coating agent of the present invention contains the composite particles of the present invention.

The coating agent contains a binder resin as necessary. As the binder resin, a resin soluble in an organic solvent or water, or an emulsion-type aqueous resin that can be dispersed in water can be used, and any known binder resin can be used. As the binder resin, for example, trade names “Dianar (registered trademark) LR-102” and “Dianar (registered trademark) BR-106” manufactured by Mitsubishi Rayon Co., Ltd., or products manufactured by Dainichi Seika Kogyo Co., Ltd. Acrylic resin such as “medium VM”; alkyd resin; polyester resin; polyurethane resin such as “E-5221P” manufactured by Daido Kasei Kogyo Co., Ltd .; chlorinated polyolefin resin; amorphous polyolefin resin; It is done. These binder resins can be appropriately selected depending on the adhesion of the coating agent to the substrate to be coated, the environment in which it is used, and the like.

The compounding amount of the composite particles is appropriately adjusted depending on the thickness of the coating (coating film) formed by the coating agent containing the binder resin, the average particle diameter of the composite particles, the coating method, the application to be used, etc. It is preferably in the range of 1 to 300 parts by weight, more preferably in the range of 5 to 100 parts by weight with respect to parts by weight. When the compounding amount of the composite particles is less than 1 part by weight with respect to 100 parts by weight of the binder resin, the matte effect may not be sufficiently obtained. In addition, when the compounding amount of the composite particles exceeds 300 parts by weight with respect to 100 parts by weight of the binder resin, the dispersion of the composite particles may occur because the viscosity of the coating agent becomes too large. Appearance defects on the surface of the coating (coating film), such as micro-cracks on the surface of the coating (coating film) obtained by coating the coating agent, or roughness on the surface of the resulting coating (coating film). May happen.

The coating agent contains a medium as necessary. As the medium, it is preferable to use a solvent (solvent) capable of dissolving the binder resin or a dispersion medium capable of dispersing the binder resin. As the dispersion medium or solvent, any of an aqueous medium and an oily medium can be used. Oil-based media include hydrocarbon solvents such as toluene, xylene and cyclohexane; 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 mono And ether solvents such as butyl ether. Examples of the aqueous medium include water and alcohols (for example, isopropanol). These media may use only 1 type and may mix and use 2 or more types. The content of the medium in the coating agent is usually in the range of 20 to 60% by weight with respect to the total amount of the coating agent.

Furthermore, coating agents include curing agents, colorants (external pigments, color pigments, metal pigments, mica powder pigments, dyes, etc.), antistatic agents, leveling agents, fluidity modifiers, ultraviolet absorbers, light stabilizers, etc. Other additives may be included.

The substrate to which the coating agent is applied is not particularly limited, and a substrate according to the application can be used.

For example, in an optical application, a glass substrate, a transparent substrate made of a transparent substrate resin, or the like is used as a substrate to be coated. By using a transparent substrate as the substrate to be coated and coating a transparent substrate with a coating agent (light diffusion coating agent) that does not contain a colorant, a light diffusion film or An optical film such as an antiglare film can be produced. In this case, the composite particles function as a light diffusing agent.

Also, matte paper can be produced by using paper as a substrate to be coated and applying a coating agent (paper coating agent) containing no colorant to form a transparent coating film.

Coating method of the coating agent is not particularly limited, and any known method can be used. Examples of the coating method include a comma direct method, a spin coating method, a spray coating method, a roll coating method, a dipping method, a knife coating method, a curtain flow method, and a laminating method. The coating agent may be diluted by adding a diluent in order 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 An alcohol solvent or the like. These diluents may be used alone or in combination of two or more. When manufacturing an optical film, it is preferable to use a method in which irregularities derived from composite particles are formed on the surface of the coating film as a coating method.

Since the coating agent of the present invention contains the composite particles of the present invention, light diffusibility can be imparted to the coating (coating film) formed from the coating agent. In the above coating agent, the hardness of the composite particles is ensured by the hydrophilic metal oxide particles attached to the surface of the polymer particles, so the scratch resistance of the coating (coating film) formed from the coating agent is improved. Can be expected. In addition, when the coating agent contains an aqueous solvent, the coating agent may be spoiled due to the excellent particle fluidity of the composite particles and the hydrophilicity of the hydrophilic metal oxide particles attached to the surface of the polymer particles. Suppressed and good dispersibility of the composite particles can be obtained. Therefore, the coating agent can form a good coating.

[Optical film]
The optical film of the present invention is an optical film including a base film and a coating formed thereon, and the coating includes the composite particles of the present invention. The optical film of the present invention can be produced by a method in which the coating agent of the present invention is applied onto a substrate film to form a coating (coating film). Specific examples of the optical film include a light diffusion film and an antiglare film.

Specific examples of the constituent material of the base film include glass and transparent resin. Examples of the transparent resin include acrylic resins such as polymethyl methacrylate, alkyl (meth) acrylate-styrene copolymers, polyesters such as polycarbonate and polyethylene terephthalate (hereinafter abbreviated as “PET”), polyethylene, polypropylene, and polystyrene. Etc. Among these transparent resins, acrylic resin, alkyl (meth) acrylate-styrene copolymer, polycarbonate, polyester, and polystyrene are preferred when excellent transparency is required for the transparent resin. These transparent resins can be used alone or in combination of two or more.

The thickness of the coating is preferably in the range of 5 to 100 μm.

(Resin composition)
The composite particles of the present invention can be used for a resin composition containing a base resin. The resin composition of the present invention contains the composite particles of the present invention and a base resin. Since the resin composition includes the composite particles of the present invention and is excellent in light diffusibility, a lighting cover (light emitting diode (LED) lighting lighting cover, fluorescent lamp lighting lighting cover, etc.), a light diffusion sheet, and a light diffusion It can be used as a raw material for light diffusers such as plates.

As the base resin, a thermoplastic resin different from the polymer components constituting the composite particles is usually used. Examples of the thermoplastic resin used as the base resin include (meth) acrylic resin, alkyl (meth) acrylate-styrene copolymer, polycarbonate, polyester, polyethylene, polypropylene, and polystyrene. Among these thermoplastic resins, acrylic resin, alkyl (meth) acrylate-styrene copolymer, polycarbonate, polyester, and polystyrene are preferable when excellent transparency is required for the base resin. These thermoplastic resins can be used alone or in combination of two or more.

The addition ratio of the composite particles to the base resin is preferably in the range of 0.1 to 70 parts by weight, preferably in the range of 1 to 50 parts by weight with respect to 100 parts by weight of the base resin. Is more preferable. When the addition ratio of the composite particles to the base resin is less than 0.1 parts by weight with respect to 100 parts by weight of the base resin, it may be difficult to impart light diffusibility to the light diffuser. When the addition ratio of the composite particles to the base resin is more than 70 parts by weight with respect to 100 parts by weight of the base resin, the light diffuser is given light diffusibility, but the light diffuser transmits light. May be low.

The method for producing the resin composition is not particularly limited, and can be produced by mixing the composite particles and the base resin by a conventionally known method such as a mechanical pulverization and mixing method. In the mechanical pulverization and mixing method, for example, the resin composition is obtained by mixing and stirring the composite particles and the base resin using an apparatus such as a Henschel mixer, a V-type mixer, a turbula mixer, a hybridizer, and a rocking mixer. Can be manufactured.

[Molded body]
The resin composition of the present invention can be molded into a molded body. The molded product of the present invention comprises the resin composition of the present invention. Specific examples of the molded body include light diffusers such as illumination covers (light emitting diode (LED) illumination illumination covers, fluorescent lamp illumination illumination covers, etc.), light diffusion sheets, and light diffusion plates.

For example, the composite particles and the base resin are mixed with a mixer and kneaded with a melt kneader such as an extruder to obtain a pellet made of a resin composition, and then the pellet is extruded or the pellet A molded body having an arbitrary shape can be obtained by injection molding after melting.

[External preparation]
The composite particles of the present invention are external preparations such as additives for improving the feeling of use such as slipperiness, additives for making skin defects such as pores, spots and wrinkles inconspicuous by the light diffusion effect, etc. Can be contained. The external preparation contains the composite particles of the present invention. When the external preparation is a liquid external preparation such as a lotion or the like, the redispersibility of the composite particles is extremely good, and the usability is excellent.

The content of the composite particles in the external preparation can be appropriately set according to the type of external preparation, but is preferably in the range of 1 to 80% by weight, and more preferably in the range of 3 to 70% by weight. preferable. When the content of the composite particles with respect to the total amount of the external preparation is less than 1% by weight, a clear effect due to the inclusion of the composite particles may not be recognized. On the other hand, if the content of the composite particles exceeds 80% by weight, a remarkable effect commensurate with the increase in content may not be recognized, which is not preferable in terms of production cost.

The external preparation can be used, for example, as an external medicine or cosmetic. The topical medicine is not particularly limited as long as it is applied to the skin, and specific examples include creams, ointments, emulsions and the like. Cosmetics include, for example, soaps, body shampoos, facial cleansing creams, scrub facial cleansers, toothpastes, and other cosmetics; funerals, face powders (loose powders, pressed powders, etc.), foundations (powder foundations, liquid foundations, emulsification types) Foundation), lipstick, lip balm, blusher, eyebrow cosmetics (eye shadow, eyeliner, mascara, etc.), nail polish and other makeup cosmetics; pre-shave lotion, body lotion and other lotions; body powder, baby powder and other bodies External preparations: skin care agents such as lotion, cream, milky lotion (skin lotion), antiperspirants (liquid antiperspirants, solid antiperspirants, cream antiperspirants, etc.), packs, hair washing cosmetics, dyes Hair, hairdressing, aromatic cosmetics, bath preparation, sun Only protection products, suntan products, include the shaving cream and the like.

The composite particles blended in the external preparation may be treated with a surface treatment agent such as an oil agent, a silicone compound and a fluorine compound, an organic powder, an inorganic powder or the like.

As the oil agent, any oil agent can be used as long as it is usually used for external preparations. For example, hydrocarbon oils such as liquid paraffin, squalane, petrolatum, paraffin wax; lauric acid, myristic acid, palmitic acid, stearic acid, olein Higher fatty acids such as acids, behenic acid, undecylenic acid, oxystearic acid, linoleic acid, lanolin fatty acid, synthetic fatty acids; ester oils such as glyceryl trioctanoate, propylene glycol dicaprate, cetyl 2-ethylhexanoate, isocetyl stearate; beeswax Waxes such as whale wax, lanolin, carnauba wax and candelilla wax; oils and fats such as linseed oil, cottonseed oil, castor oil, egg yolk oil, coconut oil; metal soaps such as zinc stearate and zinc laurate; cetyl alcohol, stearyl Alcohol, oleyl Higher alcohols such as alcohol and the like. Further, the method of treating the composite particles with the oil agent is not particularly limited. For example, a dry method in which an oil agent is added to the composite particles and the oil agent is coated by stirring with a mixer or the like, and the oil agent is ethanol, propanol, ethyl acetate. A wet method for coating an oil agent can be used by dissolving in a suitable solvent such as hexane by heating, adding composite particles thereto, mixing and stirring, and then removing the solvent under reduced pressure or removing by heating.

As the silicone compound, any silicone compound can be used as long as it is usually used in external preparations. For example, dimethylpolysiloxane, methylhydrogenpolysiloxane, methylphenylpolysiloxane, acrylic-silicone graft polymer, organic silicone resin partially crosslinked Type organopolysiloxane polymer. The method for treating the composite particles with the silicone compound is not particularly limited, and for example, the dry method or the wet method described above can be used. In addition, if necessary, a baking treatment may be performed, or in the case of a reactive silicone compound, a reaction catalyst or the like may be added as appropriate.

The fluorine compound may be any compound as long as it is usually blended with an external preparation, and examples thereof include perfluoroalkyl group-containing esters, perfluoroalkylsilanes, perfluoropolyethers, and polymers having a perfluoro group. A method for treating the composite particles with the fluorine compound is not particularly limited, and for example, the dry method or the wet method described above can be used. In addition, if necessary, a baking treatment may be performed, or in the case of a reactive fluorine compound, a reaction catalyst or the like may be added as appropriate.

Examples of the organic powder include natural polymer compounds such as gum arabic, tragacanth gum, guar gum, locust bean gum, karaya gum, iris moss, quince seed, gelatin, shellac, rosin, and casein; sodium carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, Semi-synthetic polymer compounds such as ethyl cellulose, sodium alginate, ester gum, nitrocellulose, hydroxypropyl cellulose, crystalline cellulose; polyvinyl alcohol, polyvinyl pyrrolidone, sodium polyacrylate, carboxyvinyl polymer, polyvinyl methyl ether, polyamide resin, silicone oil, Nylon particles, polymethyl methacrylate particles, crosslinked polystyrene particles, silicone particles, urethane particles, Ethylene particles include resin particles such as fluorine resin particles. Examples of the inorganic powder include iron oxide, ultramarine blue, salmon, chromium oxide, chromium hydroxide, carbon black, manganese violet, titanium oxide, zinc oxide, talc, kaolin, mica, calcium carbonate, magnesium carbonate, and silicic acid. Examples thereof include aluminum, barium silicate, calcium silicate, magnesium silicate, silica, zeolite, barium sulfate, calcined calcium sulfate (baked gypsum), calcium phosphate, hydroxyapatite, and ceramic powder. These organic powders and inorganic powders may be subjected to surface treatment in advance. As the surface treatment method, a known surface treatment technique as described above can be used.

Moreover, the main agent or additive generally used can be mix | blended with the said external preparation according to the objective in the range which does not impair the effect of this invention. Examples of such a main agent or additive include water, lower alcohol (alcohol having 5 or less carbon atoms), fats and oils, hydrocarbons, higher fatty acids, higher alcohols, sterols, fatty acid esters, metal soaps, moisturizers, Surfactant, polymer compound, coloring material raw material, fragrance, clay minerals, antiseptic / bactericidal agent, anti-inflammatory agent, antioxidant, ultraviolet absorber, organic-inorganic composite particle, pH adjuster (triethanolamine, etc.), Special blending additives, active pharmaceutical ingredients, etc. are mentioned.

Specific examples of the fats and oils include avocado oil, almond oil, olive oil, cacao fat, beef tallow, sesame fat, wheat germ oil, safflower oil, shea butter, turtle oil, straw oil, persic oil, castor oil, grape oil , Macadamia nut oil, mink oil, egg yolk oil, owl, palm oil, rosehip oil, hydrogenated oil, silicone oil, orange luffy oil, carnauba wax, candelilla wax, whale wax, jojoba oil, montan wax, beeswax, lanolin, etc. It is done.

Specific examples of the hydrocarbon include liquid paraffin, petrolatum, paraffin, ceresin, microcrystalline wax, squalane and the like.

Specific examples of the higher fatty acid include fatty acids having 11 or more carbon atoms such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, behenic acid, undecylenic acid, oxystearic acid, linoleic acid, lanolin fatty acid, and synthetic fatty acid. Is mentioned.

Specific examples of the higher alcohol include lauryl alcohol, cetyl alcohol, cetostearyl alcohol, stearyl alcohol, oleyl alcohol, behenyl alcohol, lanolin alcohol, hydrogenated lanolin alcohol, hexyldecanol, octyldecanol, isostearyl alcohol, jojoba alcohol And alcohols having 6 or more carbon atoms such as decyltetradecanol.

Specific examples of the sterol include cholesterol, dihydrocholesterol, phytocholesterol and the like.

Specific examples of the fatty acid esters include linoleic acid esters such as ethyl linoleate; lanolin fatty acid esters such as lanolin fatty acid isopropyl; lauric acid esters such as hexyl laurate; isopropyl myristate, myristyl myristate, cetyl myristate, myristic acid Myristic acid esters such as octyldecyl and octyldodecyl myristate; oleic acid esters such as decyl oleate and octyldodecyl oleate; dimethyloctanoic acid esters such as hexyldecyl dimethyloctanoate; cetyl isooctanoate (cetyl 2-ethylhexanoate) Isooctanoic acid ester such as decyl palmitate; glyceryl trimyristate, tri (caprylic / capric) glycerin, propylene dioleate Glycol, triisostearate glycerin, triisooctanoate glycerin, cetyl lactate, myristyl lactate, diisostearyl malate, cholesteryl isostearate, cyclic alcohol fatty acid esters such as 12 hydroxystearic acid cholesteryl, and the like.

Specific 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.

Specific examples of the humectant include glycerin, propylene glycol, 1,3-butylene glycol, polyethylene glycol, sodium dl-pyrrolidonecarboxylate, sodium lactate, sorbitol, sodium hyaluronate, polyglycerin, xylit, maltitol and the like. It is done.

Specific examples of the surfactant include anionic surfactants such as higher fatty acid soaps, higher alcohol sulfates, N-acyl glutamates and phosphates; cationic interfaces such as amine salts and quaternary ammonium salts. Active agents: amphoteric surfactants such as betaine type, amino acid type, imidazoline type, lecithin; fatty acid monoglyceride, polyethylene glycol, propylene glycol fatty acid ester, sorbitan fatty acid ester (for example, sorbitan isostearate), sucrose fatty acid ester, polyglycerin fatty acid Nonionic surfactants such as esters and ethylene oxide condensates are listed.

Specific examples of the polymer compound include natural polymer compounds such as gum arabic, gum tragacanth, guar gum, locust bean gum, karaya gum, iris moss, quince seed, gelatin, shellac, rosin, and casein; sodium carboxymethyl cellulose, hydroxyethyl cellulose, Semi-synthetic polymer compounds such as methyl cellulose, ethyl cellulose, sodium alginate, ester gum, nitrocellulose, hydroxypropyl cellulose, crystalline cellulose; polyvinyl alcohol, polyvinyl pyrrolidone, sodium polyacrylate, carboxyvinyl polymer, polyvinyl methyl ether, polyamide resin, silicone Oil, nylon particles, poly (meth) acrylate particles (for example, polymethyl methacrylate particles), Polystyrene particles, silicone particles, urethane particles, synthetic polymer compound of the resin particles such as polyethylene particles. In the present application documents, “(meth) acryl” means methacryl or acryl.

Specific examples of the color material raw material include iron oxide (red iron oxide, yellow iron oxide, black iron oxide, etc.), ultramarine blue, sweet potato, chromium oxide, chromium hydroxide, carbon black, manganese violet, titanium oxide, zinc oxide, Talc, kaolin, calcium carbonate, magnesium carbonate, mica, aluminum silicate, barium silicate, calcium silicate, magnesium silicate, silica, zeolite, barium sulfate, calcined calcium sulfate (baked gypsum), calcium phosphate, hydroxyapatite, ceramic powder And inorganic pigments such as azo, nitro, nitroso, xanthene, quinoline, anthraquinoline, indigo, triphenylmethane, phthalocyanine, and pyrene.

In addition, as the powder raw material such as the above-described polymer compound powder raw material and coloring material raw material, those subjected to surface treatment in advance can be used. As a surface treatment method, 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. Fluorine compound treatment with perfluoroalkyl group-containing ester, perfluoroalkylsilane, perfluoropolyether and polymer having perfluoroalkyl group, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, etc. Silane coupling agent treatment with isopropyl triisostearoyl titanate, titanium coupling agent treatment with isopropyl tris (dioctylpyrophosphate) titanate, metal soap treatment, acylglutami Amino treatment with acid, lecithin treatment with hydrogenated egg yolk lecithin, collagen treatment, polyethylene process, moisture retention treatment, an inorganic compound treatment, and processing methods such as mechanochemical treatment.

Specific examples of the clay minerals include components having several functions such as extender pigments and adsorbents, such as talc, mica, sericite, titanium sericite (sericite coated with titanium oxide), and white cloud. Mother, VEEGUM (registered trademark) manufactured by Vanderbilt, and the like.

Specific examples of the fragrance include anisaldehyde, benzyl acetate, geraniol and the like. Specific examples of the antiseptic / bactericidal agent include methyl paraben, ethyl paraben, propyl paraben, benzalkonium, benzethonium and the like. Specific examples of the antioxidant include dibutylhydroxytoluene, butylhydroxyanisole, propyl gallate, tocopherol and the like. Specific examples of the anti-inflammatory agent include ε-aminocaproic acid, glycyrrhizic acid, dipotassium glycyrrhizinate, β-glycyrrhetinic acid, lysozyme chloride, guaiazulene, hydrocortisone and the like. These can be used individually or in mixture of 2 or more types. Specific examples of the ultraviolet absorber include inorganic absorbents such as fine particle titanium oxide, fine particle zinc oxide, fine particle cerium oxide, fine particle iron oxide, fine particle zirconium oxide, benzoic acid-based, paraaminobenzoic acid-based, and anthranilic acid-based. And organic absorbents such as salicylic acid, cinnamic acid, benzophenone, and dibenzoylmethane.

Specific examples of the special combination additive include hormones such as estradiol, estrone, ethinyl estradiol, cortisone, hydrocortisone, prednisone, vitamins such as vitamin A, vitamin B, vitamin C, vitamin E, citric acid, tartaric acid, lactic acid Skin astringents such as aluminum chloride, aluminum sulfate / potassium sulfate, allantochlorohydroxyalumonium, zinc paraphenol sulfonate, zinc sulfate, cantalis tincture, pepper tincture, ginger tincture, assembly extract, garlic extract, hinokitiol, carpronium chloride And hair growth promoters such as pentadecanoic acid glyceride, vitamin E, estrogen, and photosensitizer, and whitening agents such as magnesium phosphate-L-ascorbate and kojic acid.

Since the external preparation contains the composite particles of the present invention having excellent particle fluidity, the external preparation has good slip properties. Moreover, when the said external preparation contains an aqueous solvent, the dispersibility of a composite particle is acquired with the hydrophilic property of the hydrophilic metal oxide particle adhering to the surface of a polymer particle.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. First, each measuring method in Examples and Comparative Examples and a method for detecting water-soluble cellulose will be described.

[Measurement method of average primary particle diameter of hydrophilic metal oxide particles]
The average primary particle size of the hydrophilic metal oxide particles (specifically, the Z average particle size calculated by the cumulant analysis method) is, for example, a particle size measuring device (“Zetasizer Nano ZS manufactured by Malvern) by a dynamic light scattering method. )).

As a measurement sample, a dispersion liquid in which hydrophilic metal oxide particles to be measured are dispersed in ion-exchanged water is used. When the assumed average primary particle size of the hydrophilic metal oxide particles is less than 100 nm, the dispersion is prepared so that the concentration of the hydrophilic metal oxide particles is 1% by weight. When the assumed average primary particle diameter of the particles is 100 nm or more, the dispersion is prepared so that the concentration of the hydrophilic metal oxide particles is 0.1% by weight. A polyethylene cell is set in the measurement part of the particle size measuring apparatus by the dynamic light scattering method (“Zetasizer Nano ZS” manufactured by Malvern), and the dispersion liquid is dispensed into the polyethylene cell. The Z average particle diameter of the metal oxide particles is measured.

The Z average particle diameter is a value obtained by analyzing measurement data of a dynamic light scattering method such as a particle dispersion using a cumulant analysis method.

In the cumulant analysis method, the average value of the particle diameter and the polydispersity index (PDI) are obtained, and the average value of the particle diameter is defined as the Z average particle diameter. Strictly speaking, the work of fitting a polynomial to the logarithm of the G1 correlation function obtained by measurement is called cumulant analysis, and the constant b in the following equation is called a second-order cumulant or Z-average diffusion coefficient.

LN (G1) = A + bt + ct ² + dt ³ + et ⁴ +...
A value obtained by converting the constant b into a particle diameter using the viscosity of the dispersion and several apparatus constants is the Z average particle diameter.

[Measurement method of volume average particle diameter of seed particles used for production of composite particles or polymer particles]
The volume average particle size of the seed particles used for the production of the composite particles or polymer particles is measured by a laser diffraction / scattering particle size distribution measuring device (“LS 13 320” manufactured by Beckman Coulter, Inc.) and a universal liquid sample module. Do.

Specifically, 0.1 g of the seed particle dispersion in 10 ml of a 0.1 wt% nonionic surfactant aqueous solution, touch mixer (manufactured by Yamato Kagaku Co., Ltd., “TOUCHMIXER MT-31”) and ultrasonic cleaner (stock) Dispersed using “ULTRASONIC CLEANER VS-150” manufactured by Vervo Crear, Inc., and used as a dispersion.

The measurement is performed in a state where the seed particles are dispersed by performing pump circulation in the universal liquid sample module, and in a state where the ultrasonic unit (ULM ULTRASONIC MODULE) is activated, and the volume average particle diameter of the seed particles ( Calculate the arithmetic mean diameter in the volume-based particle size distribution. The measurement conditions are shown below.

Medium = Water Refractive index of medium = 1.333
Refractive index of solid = refractive index of seed particles (when seed particles are polymethyl methacrylate particles, 1.495)
PIDS relative concentration: about 40-55%

[Measurement method of volume average particle diameter of composite particle or polymer particle and coefficient of variation of particle diameter]
The volume average particle diameter of the composite particles or polymer particles is measured by Coulter Multisizer III (measurement device manufactured by Beckman Coulter, Inc.). Measurement shall be performed using an aperture calibrated according to the Multisizer ™ 3 User's Manual issued by Beckman Coulter, Inc.

In addition, the aperture used for the measurement is appropriately selected according to the size of the particles to be measured (composite particles or polymer particles). When an aperture having a size of 50 μm was selected, the current (aperture current) was set to −800 and the gain (gain) was set to 4.

As a sample for measurement, 0.1 g of particles to be measured (composite particles or polymer particles) in 10 ml of a 0.1% by weight nonionic surfactant aqueous solution (TOUCMIXER MT-31, manufactured by Yamato Scientific Co., Ltd.). )) And an ultrasonic cleaner (“ULTRASONIC CLEANER VS-150” manufactured by VervoCrea Co., Ltd.) and used as a dispersion. During the measurement, the beaker is stirred gently to the extent that bubbles do not enter, and the measurement ends when 100,000 particles are measured. The volume average particle diameter of the particles is an arithmetic average in a volume-based particle size distribution of 100,000 particles.

The coefficient of variation (CV value) of the particle diameter of the composite particles or polymer particles is calculated by the following formula.
Coefficient of variation of particle diameter of composite particle or polymer particle = (standard deviation of particle size distribution based on volume of composite particle or polymer particle ÷ volume average particle diameter of composite particle or polymer particle) × 100

[Measurement method of specific surface area (actual value)]
The specific surface area of the particles (composite particles or polymer particles) was measured by the BET method (nitrogen adsorption method) described in ISO 9277 1st edition JIS Z 8830: 2001. For the particles to be measured (composite particles or polymer particles), the BET nitrogen adsorption isotherm was measured using an automatic specific surface area / pore distribution measuring device Tristar 3000 manufactured by Shimadzu Corporation. The specific surface area was calculated using the method. After performing the pretreatment by the heated gas purge, the measurement was performed using the constant volume method under the condition of the adsorbate cross section of 0.162 nm ² using nitrogen as the adsorbate. Specifically, the pretreatment is performed by performing a nitrogen purge for 20 minutes while heating the container containing the particles at 65 ° C., allowing to cool to room temperature, and then heating the container at 65 ° C. This was performed by performing vacuum deaeration until the pressure in the container was 0.05 mmHg or less.

[Calculation method of (actual value of specific surface area) / (calculated value of specific surface area)]
The volume average particle diameter of the particles (composite particles or polymer particles) is D (μm), the density of the particles is ρ (g / cm ³ ), the shape of the particles is assumed to be a true sphere, and all of the particles Assuming that has a particle diameter equal to the volume average particle diameter D, the calculated value (m ² / g) of the specific surface area of the particles is the following formula (calculated value of specific surface area) = 6 / ( ρ × D)
Is calculated by

Therefore, the ratio between the calculated value of the specific surface area (m ² / g) and the actual value of the specific surface area of the particles obtained by actual measurement (m ² / g) (actual value of the specific surface area) / (ratio Calculated surface area)
Is the following formula (actual value of specific surface area) / (calculated value of specific surface area)
= (Actual value of specific surface area) × ρ × D / 6
Is calculated by

[Density measurement method]
The density of the particles (composite particles or polymer particles) is measured by the method A described in “Pigment Test Method—Part 11: Density—Section 1: Pycnometer Method” of JIS K 5101-11-1: 2004. In accordance with the above, the following apparatus and reference liquid (substitution liquid with known density) were used, and the density of the particles (sample) was calculated by the following calculation formula.
Apparatus: Pycnometer with a volume of 50 ml Reference solution: 99.5% ethanol (density d ¹⁵ = 15.95 g / cm ³ at 15 ° C.)
(a formula)
ρ = m _s × ρ _w (m _a −m _b + m _s )
ρ: Sample density (g / cm ³ )
m _s : sample weight (g)
ρ _w : density of reference solution at 15 ° C. (g / cm ³ )
m _a : weight of the pycnometer filled with the reference solution (g)
m _b : weight of the pycnometer filled with the sample and the reference solution (g)

[Method for measuring content of hydrophilic metal oxide particles]
For the composite particles or polymer particles obtained in Examples and Comparative Examples described later, the ignition residue is almost equal to the content (% by weight) of the hydrophilic metal oxide particles. The ignition residue measured by the minute measurement method is defined as the content (% by weight) of the hydrophilic metal oxide particles.

(Measurement method of ignition residue)
After weighing 1.0 g of particles to be measured (composite particles or polymer particles), the weighed particles are burned off in an electric furnace at 550 ° C. for 30 minutes, and the weight (g) of the remaining residue is measured. And the weight (g) of the measured residue is remove | divided by the weight (1.0g) of the particle | grains before a measurement, and it converts into a percentage and obtains an ignition residue (weight%).

[Measurement method of evaluation value showing particle fluidity]
100 g of particles to be measured (composite particles or polymer particles) were weighed to make a measurement sample. Then, for the particles in the measurement sample, an avalanche energy change AE (kJ) before and after avalanche is used as an evaluation value indicating particle fluidity using a powder fluidity measuring device (“Powder Analyzer REVOLUTION” manufactured by Mercury Scientific). / Kg) was measured under the following measurement conditions. It shows that particle | grain fluidity is so high that the value of this AE is low.
<Measurement conditions>
Measure avalanche 150 times at 0.3 rpm

[Hydrophilicity test]
100 g of ion-exchanged water is added to a beaker, and 0.2 g of particles to be measured (composite particles or polymer particles) are placed on the liquid surface in a standing state. If the particles are dispersed in water after a lapse of less than 1 hour, it is judged that the particles have dispersibility in water (has hydrophilicity), and the particles do not settle from the liquid level even after 1 hour or more. It was judged that the particles have no dispersibility in water (no hydrophilicity).

[Method for measuring the amount of water-soluble cellulose adsorbed on hydrophilic metal oxide particles]
For some examples, using a dispersion medium containing hydrophilic metal oxide particles adsorbed with water-soluble cellulose obtained in the composite particle production process, water-soluble celluloses per gram of hydrophilic metal oxide particles The amount of adsorption (g) was measured by the following method.

After 0.25 g of a dispersion medium containing hydrophilic metal oxide particles adsorbed with water-soluble celluloses is diluted by adding 1 g of ion exchange water, a centrifuge (“Hitachi High-Speed Cooling Centrifuge manufactured by Hitachi High-Technologies Corporation) is used. Using HIMAC CR22GII ”), centrifuge at 25000 G for 30 minutes. 1 ml of 5% phenol aqueous solution is added to 1 ml of the obtained supernatant, 5 ml of concentrated sulfuric acid is added, and the mixture is allowed to stand for 10 minutes, and then left in an aqueous solution at 25 ° C. for 10 minutes to obtain a measurement sample. . For the measurement sample, the absorbance at 485 nm was measured with an ultraviolet-visible spectrophotometer (“UV-visible spectrophotometer UV-2450” manufactured by Shimadzu Corporation), and a calibration curve (relationship between the absorbance and the concentration of water-soluble celluloses). Is used to determine the concentration (g / l) of water-soluble celluloses in the supernatant.

The calibration curve is created by the following method. That is, three types of aqueous solutions with different concentrations are prepared by adding 0.01 g, 0.05 g, and 0.1 g of water-soluble cellulose used in preparing the dispersion medium to 100 g of ion-exchanged water. 0.25 g of each prepared aqueous solution is diluted with 0.75 g of ion-exchanged water, and the absorbance of each diluted aqueous solution is measured. Then, a calibration curve of a linear curve is created by plotting the weight and absorbance of water-soluble celluloses in the aqueous solution.

And the adsorption amount (g) of water-soluble cellulose per 1g of hydrophilic metal oxide particles is calculated | required with the following formula | equation.
D = (W _H −C × V) ÷ Ws
D: Adsorption amount of water-soluble celluloses per gram of hydrophilic metal oxide particles (g)
C: Concentration (g / l) of water-soluble celluloses in the supernatant
W _H : Weight of water-soluble cellulose used for production of composite particles (g)
Ws: Weight of hydrophilic metal oxide particles used for production of composite particles (g)
V: Volume of aqueous medium (l) used for the preparation of the dispersion medium in the production of composite particles

[Method for detecting water-soluble celluloses present on the surface of composite particles]
The cellulose present as a residue on the surface of the composite particle is detected by the following method. That is, first, 10 g of the composite particles are precisely weighed into a beaker having an internal volume of 300 ml. Next, after adding about 150 mL of distilled water to the contents of the beaker, a few drops of methanol are added while stirring until the composite particles are dispersed throughout the liquid without layer separation, and stirred for about 30 minutes. After stirring, the mixture was centrifuged at a rotational speed of 3000 rpm for 20 minutes. Filter through 5C filter paper. The obtained filtrate was collected in a beaker, concentrated to dryness to about 5 ml without being completely dried, then filtered through “GL Chromatodisc” (aqueous science company 13A, pore size 0.45 μm), and the filtrate. Was completely dried (solvent distilled off) to obtain a dried product (an extract with distilled water and methanol). Then, about the obtained dried solid, the peak derived from water-soluble cellulose is detected by infrared spectroscopy (single reflection type ATR (total reflection) method) with the following apparatus and conditions.

・ Measuring device: Fourier transform infrared spectrophotometer (product name: Nicolet
(Registered trademark) iS10 ", Thermo
SCIENTIFIC) and single reflection type horizontal ATR (product name “Smart iTR”,
(Thermo SCIENTIFIC)
ATR crystal: diamond and ZnSe lens, angle = 42 °
Measurement method: Single ATR method Measurement wave number range: 4000 cm ⁻¹ to 650 cm ⁻¹
-Wave depth dependence of measurement depth: No correction-Detector: Deglycated triglycine sulfate (DTGS) detector and KBr beam splitter-Resolution: 4 cm ^-1
・ Number of integration: 16 times (same for background measurement)

[Production Example 1 of Seed Particles]
(Manufacture of primary seed particles)
In 3000 g of pure water as an aqueous medium, 520 g of ethyl methacrylate as a vinyl monomer and 9.2 g of n-octyl mercaptan as a molecular weight modifier were charged into a 5 L autoclave and heated to 55 ° C. Thereafter, an aqueous solution prepared by dissolving 2.60 g of potassium peroxodisulfate as a polymerization initiator in 120 g of pure water was added to the contents of the autoclave and purged with nitrogen. Thereafter, polymerization was carried out at 55 ° C. for 12 hours, and primary seed particles having a volume average particle diameter of 0.75 μm could be obtained in a slurry state.

(Manufacture of secondary seed particles)
In 500 g of methyl methacrylate as a vinyl monomer, 5.3 g of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was dissolved to obtain a monomer mixture.

The obtained monomer mixture was mixed with 2000 g of ion-exchanged water as an aqueous medium containing 5.3 g of sodium dioctyl sulfosuccinate as a non-reactive surfactant in a container having an internal volume of 5 L, and a high-speed stirrer (Trade name “Homomixer MARK II 2.5 type”, manufactured by Primix Co., Ltd.) was processed at a rotational speed of 8000 rpm for 10 minutes to obtain an emulsion. To this emulsion, 32 g of the primary seed particle slurry was added and the mixture was stirred for 6 hours. It was confirmed with an optical microscope that the monomer mixture in the emulsion was completely absorbed by the primary seed particles.

Thereafter, this dispersion and 1000 g of an aqueous solution in which 19 g of polyvinylpyrrolidone (PVP K-90 manufactured by Nippon Shokubai Co., Ltd.) as a polymer dispersion stabilizer are dissolved are placed in an autoclave having an internal volume of 5 L, and stirred at 60 ° C. And secondary seed particles having a volume average particle diameter of 3.5 μm (hereinafter referred to as “3.5 μm secondary seed particles”) were obtained in a slurry state.

[Production Example 2 of Seed Particles]
(Manufacture of primary seed particles)
In an autoclave having an internal volume of 5 L, 520 g of ethyl methacrylate as a vinyl monomer and 5.6 g of n-octyl mercaptan as a molecular weight modifier are charged into 3000 g of pure water as an aqueous medium, and 70 ° C. The temperature was raised to. Thereafter, an aqueous solution prepared by dissolving 2.68 g of potassium peroxodisulfate as a polymerization initiator in 125 g of pure water was added to the contents of the autoclave and purged with nitrogen. Thereafter, polymerization was carried out at 70 ° C. for 12 hours, and primary seed particles having a volume average particle diameter of 0.45 μm could be obtained in a slurry state.

(Manufacture of secondary seed particles)
In an autoclave having an internal volume of 5 L, 360 g of methyl methacrylate as a vinyl monomer and 3.6 g of n-octyl mercaptan as a molecular weight modifier in 3200 g of pure water as an aqueous medium and the primary seed particles (volume average particles) 250 g of slurry having a diameter of 0.45 μm was added and the temperature was raised to 70 ° C. Thereafter, an aqueous solution in which 1.80 g of potassium peroxodisulfate as a polymerization initiator was dissolved in 125 g of pure water was added to the contents of the autoclave and purged with nitrogen. Thereafter, polymerization was performed at 70 ° C. for 12 hours, and secondary seed particles having a volume average particle diameter of 1.0 μm (hereinafter referred to as “1.0 μm secondary seed particles”) were obtained in a slurry state.

[Example 1: Production example of composite particles]
In a 5 L container having a stirrer, 1000 g of ion-exchanged water as an aqueous medium and 5.0 g of sodium dioctyl sulfosuccinate as a non-reactive surfactant were charged. The contents of this container were mixed with 900 g of methyl methacrylate (MMA) as a vinyl monomer and 100 g of ethylene glycol dimethacrylate (EGDMA), and 2,2′-azobis (2,4-dimethylvalero) as a polymerization initiator. Nitrile) (ADVN) 0.6 g and benzoyl peroxide (BPO) 0.6 g were added. The contents of the container were stirred for 10 minutes at a rotational speed of 8000 rpm with a high-speed stirrer (trade name “Homomixer MARK II 2.5 type”, manufactured by Primix Co., Ltd.) to obtain an emulsion. To the obtained emulsion, 80 g of the slurry of 3.5 μm secondary seed particles was added and stirred at 30 ° C. with the stirring device at a rotation speed of 100 rpm for 3 hours. The body (methyl methacrylate and ethylene glycol dimethacrylate) was absorbed.

In an autoclave having an internal volume of 5 L, 1800 g of ion-exchanged water and Snowtex (registered trademark) O-40 (abbreviated as “ST-O-40” as hydrophilic metal oxide particles, colloidal silica manufactured by Nissan Chemical Industries, Ltd., Average primary particle size 25 nm, solid content 40 wt%) 85 g (SiO ₂ pure amount 34 g), Metrolose (registered trademark) 65SH-50 (abbreviated as “HPMC (65SH-50)”) as a water-soluble cellulose, Shin-Etsu Chemical Co., Ltd. 6.8 g) (hydroxypropyl methylcellulose manufactured by Co., Ltd., cloud point 65 ° C.) was added and mixed at a temperature of 60 ° C. for 24 hours. When the amount of water-soluble cellulose adsorbed on hydrophilic metal oxide particles (silica particles) was measured using this dispersion medium, 5.02 mg / m ² of water-soluble cellulose was adsorbed on the hydrophilic metal oxide particles. It was. In the obtained mixture, the emulsion, 16 g of Aqualon (registered trademark) RN2025 (nonionic type, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., pure content 25% by weight) as a reactive surfactant, Sodium nitrate 0.6g was added and superposition | polymerization was performed at 60 degreeC for 5 hours. Thereafter, a solid was obtained by filtration, and after washing with 5 L of water, the solid content was taken out and dried in a vacuum dryer for 12 hours to obtain composite particles.

When the cross section of the obtained composite particle was confirmed by SEM (scanning electron microscope) and TEM (transmission electron microscope), as shown in FIG. 1 and FIG. 2, the composite particle was composed of polymer particles, Including the hydrophilic metal oxide particles adhering to the coalesced particles (black dot portion of the TEM image in FIG. 2), it was recognized that there were many convex portions on the surface derived from the hydrophilic metal oxide particles. Moreover, in this composite particle, it was recognized that the surface of the polymer particle was covered with a layer made of hydrophilic metal oxide particles. In addition, it is estimated that the convex part of the surface was formed by mixing hydrophilic metal oxide particles and small particles of vinyl monomer (so-called emulsion).

When the particle size distribution of the obtained composite particles was measured, the volume average particle size was 14.5 μm, the particle size variation coefficient (CV value) was 11.5%, and the particle size distribution was sharp. Further, the obtained composite particles have a density of 1.2 g / cm ³ , an actual measurement of specific surface area of 1.16 m ² / g, (actual measurement of specific surface area) / (calculated value of specific surface area) of 3.37, The content of the hydrophilic metal oxide particles (ignition residue) was 1.40% by weight, and the AE indicating particle fluidity was 30.8 kJ / kg.

In addition, as a result of carrying out the hydrophilicity test, since sedimentation starts immediately, the obtained composite particles have dispersibility in water, that is, have hydrophilicity (this is because the surface of the composite particles has a hydrophilic metal). It was confirmed that oxide particles were present).

Further, the obtained composite particles were subjected to infrared spectroscopic measurement of the extract by the method described in the section “Method for detecting water-soluble cellulose present on the composite particle surface”. In FIG. 1, the infrared absorption spectrum of the extract of the obtained composite particles is shown by a solid line, and the infrared absorption spectrum of hydroxypropylmethylcellulose is shown by a broken line. From the measurement results shown in FIG. 1, in the infrared absorption spectrum of the composite particle extract, an absorption peak due to C—O—C bond is observed in the vicinity of wave number 1110 to 1000 cm ⁻¹ , and CH ₃ bending vibration and − Absorption peaks due to O—H bending vibration were observed at wave numbers of 1500 to 1250 cm ⁻¹ . Since this is an infrared absorption spectrum similar to that of hydroxypropylcellulose, it can be inferred that hydroxypropylmethylcellulose is present in the composite particle extract.

[Example 2: Production example of composite particles]
Composite particles were obtained in the same manner as in Example 1 except that 70 g of 1.0 μm secondary seed particles were used instead of 80 g of the slurry of 3.5 μm secondary seed particles.

When the particle size distribution of the obtained composite particles was measured, the volume average particle size was 4.5 μm, the particle size variation coefficient (CV value) was 12.0%, and the particle size distribution was sharp. Further, the obtained composite particles have a density of 1.2 g / cm ³ , an actual measurement of specific surface area of 2.58 m ² / g, (actual measurement of specific surface area) / (calculated value of specific surface area) of 2.32. The content of the hydrophilic metal oxide particles (ignition residue) was 3.20% by weight, and the AE indicating particle fluidity was 42.0 kJ / kg.

Further, as a result of carrying out the hydrophilicity test, since sedimentation immediately started, it was confirmed that the obtained composite particles had dispersibility in water, that is, hydrophilicity.

[Example 3: Production example of composite particles]
As reactive surfactant, instead of 16 g of AQUALON (registered trademark) RN2025, 4 g of ADEKA rear soap (registered trademark) ER-10 (nonionic type, manufactured by ADEKA Corporation) was used in the same manner as in Example 1. Thus, composite particles were obtained.

When the particle size distribution of the obtained composite particles was measured, the volume average particle size was 14.5 μm, the particle size variation coefficient (CV value) was 11.4%, and the particle size distribution was sharp. Further, the obtained composite particles have a density of 1.2 g / cm ³ , an actual measurement of specific surface area of 1.15 m ² / g, (actual measurement of specific surface area) / (calculated value of specific surface area) of 3.34, The content of the hydrophilic metal oxide particles (ignition residue) was 1.40% by weight, and the AE indicating particle fluidity was 30.6 kJ / kg.

[Example 4: Production example of composite particles]
As the hydrophilic metal oxide particles, instead of 85 g of Snowtex (registered trademark) O-40 (SiO ₂ pure amount 34 g), Snowtex (registered trademark) O (abbreviated as “ST-O”, manufactured by Nissan Chemical Industries, Ltd.) A composite particle was obtained in the same manner as in Example 1 except that 85 g (a pure content of SiO ₂ 17 g) of colloidal silica, average primary particle diameter 13 nm, solid content 20 wt% was used.

When the particle size distribution of the obtained composite particles was measured, the volume average particle size was 14.3 μm, the particle size variation coefficient (CV value) was 11.7%, and the particle size distribution was sharp. The obtained composite particles had a density of 1.2 g / cm ³ , an actual measurement of specific surface area of 1.65 m ² / g, (actual measurement of specific surface area) / (calculated value of specific surface area) of 4.72. The content of the hydrophilic metal oxide particles (ignition residue) was 1.40% by weight, and the AE indicating particle fluidity was 30.5 kJ / kg.

[Example 5: Production example of composite particles]
As water-soluble celluloses, instead of Metros (registered trademark) 65SH-50 6.8 g, Metrows (registered trademark) 65SH-400 (abbreviation “HPMC (65SH-400)”, Shin-Etsu Chemical Co., Ltd. hydroxypropyl methylcellulose, Composite particles were obtained in the same manner as in Example 1 except that 6.8 g (cloud point 65 ° C.) was used.

When the particle size distribution of the obtained composite particles was measured, the volume average particle size was 14.4 μm, the particle size variation coefficient (CV value) was 11.5%, and the particle size distribution was sharp. Further, the obtained composite particles have a density of 1.2 g / cm ³ , an actual measurement of specific surface area of 1.17 m ² / g, (actual measurement of specific surface area) / (calculated value of specific surface area) of 3.37, The content of the hydrophilic metal oxide particles (ignition residue) was 1.40% by weight, and the AE indicating particle fluidity was 30.2 kJ / kg.

[Example 6: Production example of composite particles]
As water-soluble celluloses, instead of Metros (registered trademark) 65SH-50 6.8 g, NISSO HPC M (Nippon Soda Co., Ltd. hydroxypropylcellulose, lower critical solution temperature 45 ° C.) 6.8 g was used. In the same manner as in Example 1, composite particles were obtained.

When the particle size distribution of the obtained composite particles was measured, the volume average particle size was 14.5 μm, the particle size variation coefficient (CV value) was 11.6%, and the particle size distribution was sharp. Further, the obtained composite particles have a density of 1.2 g / cm ³ , an actual measurement of specific surface area of 1.16 m ² / g, (actual measurement of specific surface area) / (calculated value of specific surface area) of 3.36, The content of the hydrophilic metal oxide particles (ignition residue) was 1.40% by weight, and the AE indicating particle fluidity was 30.5 kJ / kg.

[Example 7: Production example of composite particles]
Instead of 900 g of methyl methacrylate (MMA) and 100 g of ethylene glycol dimethacrylate (EGDMA), 800 g of methyl methacrylate (MMA), 100 g of styrene, and 100 g of ethylene glycol dimethacrylate (EGDMA) were used as vinyl monomers. Except for the above, composite particles were obtained in the same manner as in Example 2.

When the particle size distribution of the obtained composite particles was measured, the volume average particle size was 4.2 μm, the particle size variation coefficient (CV value) was 12.1%, and the particle size distribution was sharp. Further, the obtained composite particles have a density of 1.2 g / cm ³ , an actual measurement of specific surface area of 2.62 m ² / g, (actual value of specific surface area) / (calculated value of specific surface area) of 2.20, The content of the hydrophilic metal oxide particles (ignition residue) was 3.20% by weight, and the AE indicating particle fluidity was 43.5 kJ / kg.

[Example 8: Production example of composite particles]
As vinyl monomers, instead of 900 g of methyl methacrylate (MMA) and 100 g of ethylene glycol dimethacrylate (EGDMA), 350 g of butyl acrylate (BA), 350 g of butyl methacrylate (BMA), and ethylene glycol dimethacrylate (EGDMA) ) 300 g, and 2,2′-azobis (2,4-dimethylvaleronitrile) (ADVN) 0.6 g and benzoyl peroxide (BPO) 0.6 g were used as polymerization initiators instead of 2,2′- Composite particles were obtained in the same manner as in Example 2 except that 6.0 g of azobis (2,4-dimethylvaleronitrile) (ADVN) and 6.0 g of benzoyl peroxide (BPO) were used.

When the particle size distribution of the obtained composite particles was measured, the volume average particle size was 4.5 μm, the particle size variation coefficient (CV value) was 11.1%, and the particle size distribution was sharp. The obtained composite particles had a density of 1.2 g / cm ³ , an actual measurement of specific surface area of 2.60 m ² / g, (actual measurement of specific surface area) / (calculated value of specific surface area) of 2.34, The content of the hydrophilic metal oxide particles (ignition residue) was 3.10% by weight, and the AE indicating particle fluidity was 42.1 kJ / kg.

[Example 9: Production example of composite particles]
As hydrophilic metal oxide particles, instead of 85 g of Snowtex (registered trademark) O-40 (SiO ₂ pure amount 34 g), an aqueous dispersion GT-10W of ultrafine silica-coated titanium oxide particles (manufactured by Sakai Chemical Industry Co., Ltd.) , Average primary particle size: 115 nm, solid content 40% by weight, silica coating amount (silica content in silica-coated metal oxide particles) 20% by weight) 85 g (pure amount of silica-coated titanium oxide particles 34 g) and polymerization As an initiator, instead of 0.6 g of 2,2′-azobis (2,4-dimethylvaleronitrile) (ADVN) and 0.6 g of benzoyl peroxide (BPO), 2,2′-azobis (2,4-dimethyl) Composite particles were obtained in the same manner as in Example 1 except that 6.0 g of valeronitrile) (ADVN) and 6.0 g of benzoyl peroxide (BPO) were used.

When the particle size distribution of the obtained composite particles was measured, the volume average particle size was 14.0 μm, the particle size variation coefficient (CV value) was 11.7%, and the particle size distribution was sharp. Further, the obtained composite particles have a density of 1.2 g / cm ³ , an actual value of measured specific surface area of 8.61 m ² / g, (measured value of specific surface area) / (calculated value of specific surface area) of 24.11, The content of the hydrophilic metal oxide particles (residue on ignition) was 2.45% by weight, and the AE indicating particle fluidity was 40.6 kJ / kg.

[Example 10: Production example of composite particles]
Composite particles were obtained in the same manner as in Example 9 except that 70 g of 1.0 μm secondary seed particles were used instead of 80 g of the slurry of 3.5 μm secondary seed particles.

When the particle size distribution of the obtained composite particles was measured, the volume average particle size was 4.7 μm, the particle size variation coefficient (CV value) was 12.1%, and the particle size distribution was sharp. The obtained composite particles had a density of 1.2 g / cm ³ , an actual measurement of specific surface area of 9.57 m ² / g, (actual measurement of specific surface area) / (calculated value of specific surface area) of 9.00, The content of the hydrophilic metal oxide particles (ignition residue) was 2.10% by weight, and the AE showing particle fluidity was 48.5 kJ / kg.

[Example 11: Production example of composite particles]
As hydrophilic metal oxide particles, instead of 85 g of ultrafine silica-coated titanium oxide aqueous dispersion GT-10W (pure amount of silica-coated titanium oxide particles 34 g), ultrafine silica-coated zinc oxide particles FINEX-30W (Sakai Chemical Industry) Composite particles were obtained in the same manner as in Example 9 except that 34 g of an average primary particle size manufactured by Co., Ltd., 137 nm, and a silica coating amount (silica content in silica-coated metal oxide particles) of 20% by weight) was used.

When the particle size distribution of the obtained composite particles was measured, the volume average particle size was 14.1 μm, the particle size variation coefficient (CV value) was 13.8%, and the particle size distribution was sharp. The obtained composite particles have a density of 1.2 g / cm ³ , an actual measurement of specific surface area of 6.63 m ² / g, (actual measurement of specific surface area) / (calculated value of specific surface area) of 18.70, The content of the hydrophilic metal oxide particles (ignition residue) was 2.35% by weight, and the AE indicating particle fluidity was 38.4 kJ / kg.

[Example 12: Production example of composite particles]
Instead of 85 g of ultrafine silica-coated titanium oxide aqueous dispersion GT-10W (pure 34 g of silica-coated titanium oxide particles) as hydrophilic metal oxide particles, an aqueous dispersion of zinc oxide particles doped with antimony “cell” Composite particles were obtained in the same manner as in Example 9, except that 170 g of “Nax (registered trademark) CX-Z330H” (manufactured by Nissan Chemical Industries, Ltd., average primary particle size: 20 nm, solid content 20 wt%) was used.

When the particle size distribution of the obtained composite particles was measured, the volume average particle size was 15.2 μm, the particle size variation coefficient (CV value) was 11.8%, and the particle size distribution was sharp. The obtained composite particles had a density of 1.2 g / cm ³ , an actual measurement of specific surface area of 3.03 m ² / g, (actual value of specific surface area) / (calculated value of specific surface area) of 9.21, The content of the hydrophilic metal oxide particles (ignition residue) was 2.10% by weight, and the AE indicating particle fluidity was 38.0 kJ / kg.

[Example 13: Production example of composite particles]
As hydrophilic metal oxide particles, instead of 85 g of ultrafine particle silica-coated titanium oxide aqueous dispersion GT-10W (pure amount of silica-coated titanium oxide particles 34 g), an aqueous dispersion of phosphorus-doped tin oxide particles “CELLAX (registered) A composite particle was obtained in the same manner as in Example 9 except that 113 g (trademark) CX-S301H (manufactured by Nissan Chemical Industries, Ltd., average primary particle size: 20 nm, solid content 30% by weight) was used.

When the particle size distribution of the obtained composite particles was measured, the volume average particle size was 15.2 μm, the particle size variation coefficient (CV value) was 12.1%, and the particle size distribution was sharp. The obtained composite particles had a density of 1.2 g / cm ³ , an actual measurement of specific surface area of 3.11 m ² / g, (actual value of specific surface area) / (calculated value of specific surface area) of 9.45, The content of the hydrophilic metal oxide particles (residue on ignition) was 2.12% by weight, and the AE indicating particle fluidity was 37.6 kJ / kg.

[Comparative Example 1: Comparative production example of composite particles]
Do not use SNOWTEX (registered trademark) O-40 as hydrophilic metal oxide particles and Metrolose (registered trademark) 65SH-400 as water-soluble celluloses, and aqualon as a reactive surfactant ( (Registered Trademark) Polymer particles were obtained in the same manner as in Example 1 except that 50 g of polyvinyl alcohol as a polymer dispersion stabilizer was used instead of 16 g of RN2025.

When the cross section of the obtained polymer particles was confirmed by SEM (scanning electron microscope), it was recognized that there was almost no surface unevenness as shown in FIG.

When the particle size distribution of the obtained polymer particles was measured, the volume average particle size was 14.5 μm and the coefficient of variation (CV value) of the particle size was 10.0%. The obtained composite particles had a density of 1.2 g / cm ³ , an actual measurement of specific surface area of 0.40 m ² / g, (actual measurement of specific surface area) / (calculated value of specific surface area) of 1.16, The AE showing particle fluidity was 84.6 kJ / kg.

Further, as a result of carrying out the hydrophilicity test, it was confirmed that there was no sedimentation even after 1 hour or more and that the obtained polymer particles were not dispersible in water, that is, were not hydrophilic.

[Comparative Example 2: Comparative production example of composite particles]
Do not use SNOWTEX (registered trademark) O-40 as hydrophilic metal oxide particles and Metrolose (registered trademark) 65SH-400 as water-soluble celluloses, and aqualon as a reactive surfactant ( (Registered Trademark) Polymer particles were obtained in the same manner as in Example 2 except that 50 g of polyvinyl alcohol as a polymer dispersion stabilizer was used instead of 16 g of RN2025.

When the particle size distribution of the obtained polymer particles was measured, the volume average particle size was 4.2 μm and the variation coefficient (CV value) of the particle size was 11.0%. Further, the obtained composite particles have a density of 1.2 g / cm ³ , an actual measurement of specific surface area of 1.00 m ² / g, (actual measurement of specific surface area) / (calculated value of specific surface area) of 0.84, The AE indicating the particle fluidity was 69.1 kJ / kg.

[Comparative Example 3: Comparative production example of composite particles]
The amount of SNOWTEX (registered trademark) O-40 used as hydrophilic metal oxide particles was changed from 85 g (SiO ₂ pure amount 34 g) to 480 g (SiO ₂ pure amount 192 g), and water-soluble celluloses Particles were obtained in the same manner as in Example 2 except that no Metroze (registered trademark) 65SH-400 and Aqualon (registered trademark) RN2025 as a reactive surfactant were used.

When the particle size distribution of the obtained particles was measured, the volume average particle diameter was 4.5 μm, and the coefficient of variation (CV value) of the particle diameter was 11.0%. The obtained particles had a density of 1.2 g / cm ³ , an actual measurement of specific surface area of 1.02 m ² / g, (actual value of specific surface area) / (calculated value of specific surface area) of 0.92, hydrophilic The content of the conductive metal oxide particles (ignition residue) was less than the lower limit of quantification, and the AE indicating particle fluidity was 61.2 kJ / kg. The obtained particles were found to contain almost no hydrophilic metal oxide particles because the ignition residue was less than the lower limit of quantification, and it was recognized that they were polymer particles rather than composite particles.

[Comparative Example 4: Comparative production example of composite particles]
The amount of SNOWTEX (registered trademark) O-40 used as hydrophilic metal oxide particles was changed from 85 g (SiO ₂ pure amount 34 g) to 210 g (SiO ₂ pure amount 84 g), and Metrows as water-soluble celluloses Example 1 except that 72 g of sodium chloride, an alkali metal salt, was used in place of 6.8 g of (registered trademark) 65SH-400, and that Aqualon (registered trademark) RN2025 as a reactive surfactant was not used. In the same manner as above, seed polymerization was attempted. However, the droplet stability of the monomer mixture in the dispersion medium was low, and composite particles could not be obtained.

[Comparative Example 5: Comparative production example of composite particles]
In a polymerization vessel having a stirrer, 150 g of water as an aqueous medium and SNOWTEX (registered trademark) O-40 (abbreviated as “ST-O-40” as hydrophilic metal oxide particles, colloidal manufactured by Nissan Chemical Industries, Ltd. 2.75 g of silica (average primary particle diameter 25 nm, solid content 40 wt%) (SiO ₂ pure amount 1.1 g) and Metrolose (registered trademark) 65SH-400 (abbreviated as “HPMC (65SH-400) as water-soluble celluloses” ), 0.22 g of hydroxypropyl methylcellulose manufactured by Shin-Etsu Chemical Co., Ltd., cloud point 65 ° C.), and mixed for 24 hours at a temperature of 60 ° C. Thus, the hydrophilic metal oxide adsorbed with water-soluble celluloses A dispersion medium containing particles (silica particles) was obtained.

Separately, 50 g of methyl methacrylate (MMA) as a vinyl monomer and 2.5 g of ethylene glycol dimethacrylate (EGDMA) and 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator ( ADVN) 0.5 g was uniformly mixed and dissolved to prepare a monomer mixture containing a polymerization initiator.

The monomer mixture containing the polymerization initiator is added to the dispersion medium in the polymerization vessel, and the mixture is stirred with a homomixer (High Flex Disperser HG-2 manufactured by SMT) at 9000 rpm for about 3 minutes. The monomer mixture was finely dispersed therein.

Thereafter, stirring was continued at a stirring speed of 70 rpm, and polymerization was performed for 6 hours after the temperature of the dispersion medium to which the monomer mixture was added reached 55 ° C.

Next, the reaction solution in the polymerization vessel was cooled to room temperature while stirring. Next, the reaction solution is suction filtered using a qualitative filter paper 101 (“Toyo Qualitative Filter Paper” manufactured by Advantech Toyo Co., Ltd.), washed with ion-exchanged water, subsequently drained, and then dried overnight in a 90 ° C. oven. As a result, composite particles were obtained.

When the particle size distribution of the obtained composite particles was measured, the volume average particle size was 7.9 μm, and the coefficient of variation (CV value) in particle size was 36.3%. The obtained composite particles have a density of 1.2 g / cm ³ , an actual measurement of specific surface area of 0.63 m ² / g, (actual value of specific surface area) / (calculated value of specific surface area) of 1.00, The content of the hydrophilic metal oxide particles (ignition residue) was 1.45% by weight, and the AE indicating particle fluidity was 56.8 kJ / kg.

For Examples 1 to 13 and Comparative Examples 1 to 5, the amount of various raw materials used in the production, the measurement result of the average primary particle diameter of the hydrophilic metal oxide particles used in the production, the particles obtained by the production (composite Particles or polymer particles) volume average particle diameter, coefficient of variation of particle diameter (CV value), actual measurement of specific surface area, (actual value of specific surface area) / (calculated value of specific surface area), hydrophilic metal oxide particles Table 1 and Table 2 show the AE measurement results indicating the content (ignition residue) and particle fluidity.

As described above, in the production methods of Comparative Examples 3 and 4 in which water-soluble cellulose is not used, composite particles including polymer particles and hydrophilic metal oxide particles attached to the surface of the polymer particles are obtained. In contrast, in the production methods of Examples 1 to 13 using water-soluble cellulose, composite particles containing polymer particles and hydrophilic metal oxide particles attached to the surface of the polymer particles Could get.

The polymer particles of Comparative Examples 1 to 3 do not contain hydrophilic metal oxide particles or hardly contain them, and thus have no hydrophilicity, whereas the composite particles of Examples 1 to 13 In addition to the polymer particles, it was found to have hydrophilicity because it contains hydrophilic metal oxide particles attached to the surface of the polymer particles.

Further, the polymer particles of Comparative Examples 1 to 3 and the composite particles of Comparative Example 5 have less surface irregularities, whereas (actual value of specific surface area) / (calculated value of specific surface area) is less than 1.20. The composite particles of Examples 1 to 13 were found to have many surface irregularities, and (actual value of specific surface area) / (calculated value of specific surface area) was 1.20 or more.

In addition, the polymer particles of Comparative Examples 1 to 3 and the composite particles of Comparative Example 5 have a particle fluidity of AE of more than 50 kJ / kg, and the particle fluidity is low, whereas the composite particles of Examples 1 to 13 It was confirmed that the particles had a high particle fluidity with an AE showing particle fluidity of 50 kJ / kg or less.

The composite particles of Comparative Example 5 have a particle size variation coefficient of more than 15% and the particle size uniformity is low, whereas the composite particles of Examples 1 to 13 have a particle size variation coefficient of 15 %, And it was confirmed that the uniformity of the particle diameter was high.

[Example 14: Production example of optical film]
1.5 g of water-based binder resin (manufactured by Daido Kasei Kogyo Co., Ltd., trade name “E-5221P”, solid content 20 wt%, urethane binder) as binder resin and 0.5 g of composite particles prepared in Example 1 The mixture was mixed to uniformly disperse the composite particles in the aqueous binder resin to prepare a coating agent (coating resin composition).

The coating agent was applied on a PET film having a thickness of 100 μm as a base film using a 100 μm applicator (width 8 cm) to form a wet coating film. The coating film on the PET film is dried by heating in a thermostat at 70 ° C. for 10 minutes, and the base film and a coating of 8 cm in length (applicator width) × 30 cm in width (dried state) A coating film) was obtained.

When the aqueous binder resin and the composite particles were mixed, the composite particles were immediately dispersed uniformly in the aqueous binder resin. Moreover, when the defect which generate | occur | produced in the coating (dry coating film) formed on the base film was confirmed by visual observation, there was no defect which occurred and the composite particles were uniformly dispersed.

[Comparative Example 6: Comparative production example of optical film]
A film was obtained in the same manner as in Example 8 except that the polymer particles prepared in Comparative Example 1 were used in place of the composite particles prepared in Example 1. When the aqueous binder resin and the composite particles were mixed, it was easy to fool. Moreover, when the defect which generate | occur | produced in the coating (dried coating film) formed on the base film was confirmed visually, there were 10 or more defects that occurred.

[Example 15: Production example of light diffusing plate]
5.0 parts by weight of the composite particles obtained in Example 10 and a methacrylic resin (trade name “Acripet (registered trademark) MF 001 G200”, manufactured by Mitsubishi Rayon Co., Ltd.), which is a transparent resin as a base resin, 100 After drying for a whole day and night in an oven set at 80 ° C. by weight, the mixture was melt-kneaded at 200 ° C. in an extruder and then pelletized to obtain pellets as a resin composition. The obtained pellets were molded by an injection molding machine under the condition of a cylinder temperature of 230 ° C. to prepare a light diffusion plate as a molded body having a thickness of 2 mm and 50 mm × 100 mm.

(Measurement of total light transmittance and haze of light diffusion plate)
The haze and total light transmittance of the light diffusion plate obtained in Example 15 were measured using a haze meter “NDH-4000” manufactured by Nippon Denshoku Industries Co., Ltd. The total light transmittance was measured according to JIS K 7361-1, and the haze was measured according to JIS K 7136. Table 3 shows the measurement results of the total light transmittance and haze of the obtained light diffusion plate.

In addition, the haze and total light transmittance shown in Table 3 are average values of measured values of three measurement samples (number of measurement samples n = 3). The haze value becomes higher as the diffusibility of the light (transmitted light) transmitted through the light diffusion plate is higher.

[Example 16: Production example of external preparation (lotion)]
0.5 parts by weight of the composite particles obtained in Example 9 were mixed with 65.0 parts by weight of ethanol, 33.0 parts by weight of purified water, and 0.1 parts by weight of a fragrance to prepare a lotion as an external preparation. . The prepared lotion had extremely good redispersibility of the composite particles and excellent usability.

The composite particles of the present invention are, for example, coating agents (coating compositions for paper), coating agents for information recording paper, or coating agents (coating compositions) used as coating agents for optical members such as optical films. A light diffusing agent blended in a light diffusing resin composition for producing a light diffuser (lighting cover, light diffusing plate, light diffusing film, etc.); An anti-blocking agent for films such as food packaging films; an external preparation such as an additive for external preparations such as cosmetics (additive for improving slipperiness or correcting skin defects such as spots and wrinkles) It can be used as a raw material.

The present invention can be implemented in various other forms without departing from the spirit or main features thereof. For this reason, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

This application also claims priority based on Japanese Patent Application No. 2015-171019 filed in Japan on August 31, 2015. By this reference, the entire contents thereof are incorporated into the present application.

Claims

A composite particle comprising polymer particles made of a vinyl monomer polymer and hydrophilic metal oxide particles attached to the surface of the polymer particles,
Assuming that the shape of the composite particle is a true sphere, from the volume average particle diameter D (μm) and density ρ (g / cm 3 ) of the composite particle, the following formula (calculated value of specific surface area) = 6 / (ρ × D)
The ratio of the calculated value of the specific surface area calculated by (m 2 / g) and the actual value of the specific surface area (m 2 / g) of the composite particles obtained by actual measurement (actual value of the specific surface area) / (Calculated value of specific surface area)
Is a composite particle characterized by being 1.20 or more.
The composite particle according to claim 1,
A composite particle further comprising water-soluble celluloses.
The composite particle according to claim 1 or 2,
A composite particle having a coefficient of variation in particle diameter of 15% or less.
The composite particle according to any one of claims 1 to 3,
A composite particle having a volume average particle diameter of 1 to 20 μm.
The composite particle according to any one of claims 1 to 4,
Composite particles, wherein the content of the hydrophilic metal oxide particles is in the range of 0.5 to 10% by weight.
The composite particle according to any one of claims 1 to 5,
An average primary particle diameter of the hydrophilic metal oxide particles is in the range of 5 to 200 nm.
The composite particle according to any one of claims 1 to 6,
A composite particle characterized by a numerical value of avalanche energy change AE before and after avalanche showing particle fluidity within a range of 10 to 50 kJ / kg.
A method for producing composite particles comprising polymer particles comprising a polymer of a vinyl monomer, and hydrophilic metal oxide particles attached to the polymer particles,
After the vinyl monomer is absorbed by the seed particles, the vinyl monomer is absorbed in an aqueous medium in the presence of hydrophilic metal oxide particles having water-soluble cellulose adsorbed on the surface and a reactive surfactant. A method for producing composite particles, comprising a polymerization step of obtaining composite particles by seed polymerization.
A method for producing composite particles according to claim 8,
Hydroxypropylcellulose and / or hydroxymethylpropylcellulose is used as the water-soluble celluloses.
A method for producing composite particles according to claim 8 or 9,
Before the polymerization step, the method includes an adsorption step of treating the hydrophilic metal oxide particles with the water-soluble celluloses to adsorb the water-soluble celluloses on the surface of the hydrophilic metal oxide particles. A method for producing composite particles.
A method for producing a composite particle according to any one of claims 8 to 10,
A method for producing composite particles, wherein a nonionic reactive surfactant is used as the reactive surfactant.
A coating agent comprising the composite particles according to any one of claims 1 to 7.
An optical film comprising a base film and a coating formed thereon,
An optical film, wherein the coating contains the composite particles according to any one of claims 1 to 7.
A resin composition comprising the polymer particles according to any one of claims 1 to 7 and a base resin.
A molded body comprising the resin composition according to claim 14.
An external preparation comprising the polymer particles according to any one of claims 1 to 7.