JP-7855402-B2 - Surface-treated silica particle dispersion

JP7855402B2JP 7855402 B2JP7855402 B2JP 7855402B2JP-7855402-B2

Inventors

西村仁希
木太純子

Assignees

株式会社日本触媒

Dates

Publication Date: 20260508
Application Date: 20220519

Claims (11)

Surface-treated silica particles having aryl groups Ar and alkyl groups R on their surface. A dispersion of surface-treated silica particles comprising a dispersion medium which is at least one selected from the group consisting of ether ester solvents, ester solvents, and aromatic hydrocarbon solvents, and an alcohol solvent, A surface-treated silica particle dispersion characterized in that the content of the alcohol-based solvent in 100% by mass of the surface-treated silica particle dispersion is 0.20 to 5% by mass.
The surface-treated silica particle dispersion according to claim 1, wherein the aryl group Ar is a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 1 to 4 carbon atoms, and the alkyl group R has 1 to 4 carbon atoms.
The surface-treated silica particle dispersion according to claim 1 or 2, wherein the aryl group Ar is derived from an arylalkoxysilane.
The surface-treated silica particle dispersion according to claim 1 or 2, wherein the alkyl group R is derived from a hexaalkyldisilazane.
The surface-treated silica particle dispersion according to claim 1 or 2, wherein the ratio of the aryl group Ar to the alkyl group R (aryl group/alkyl group) is 0.01 to 3.0.
The surface-treated silica particle dispersion according to claim 1 or 2, wherein, when the surface-treated silica particle dispersion is 100 parts by mass, the amount of Si present in the medium other than the surface-treated silica particles is 0.05 parts by mass or less.
The surface-treated silica particle dispersion according to claim 1 or 2, wherein, when the surface-treated silica particle dispersion is 100 parts by mass, the amount of Si present in the medium other than the surface-treated silica particles is greater than 0.05 parts by mass.
The surface-treated silica particle dispersion according to claim 1 or 2, wherein the content of surface-treated silica particles in 100% by mass of the surface-treated silica particle dispersion is 10 to 50% by mass.
The surface-treated silica particle dispersion according to claim 1 or 2, wherein the carbon concentration in 100% by mass of the surface-treated silica particles is 2 to 10% by mass.
The surface-treated silica particle dispersion according to claim 1 or 2, wherein the average primary particle diameter of the surface-treated silica particles is 10 to 100 nm.
A resin composition comprising a surface-treated silica particle dispersion according to claim 1 or 2, and a resin.

Description

This invention relates to a surface-treated silica particle dispersion. Silica particle dispersions, obtained by dispersing silica particles in a solvent, can improve properties such as strength, hardness, heat resistance, and insulation without impairing the moldability or transparency of resins when mixed with resins or resin raw materials. Therefore, they are useful in applications such as adhesives, dental materials, optical components, coating materials (for hard coatings and anti-glare coatings), and nanocomposite materials. Furthermore, silica particles with very small particle sizes are also used as abrasives due to their hardness. Because silica particles have a hydrophilic surface, techniques have been proposed to hydrophobize the surface to increase their affinity with highly hydrophobic dispersion media and resins. For example, Patent Document 1 describes a method in which silica particles are surface-treated with phenyltrimethoxysilane and hexamethyldisilazane, aggregated and precipitated in water and isopropanol, then hydrochloric acid is added to precipitate the silica particles, and the solid silica particles are obtained by filtration. This solid is then mixed with methyl ethyl ketone to obtain a dispersion sample of silica particles. Patent Document 2 describes a method in which phenyltrimethoxysilane and hexamethyldisilazane are added to a methanol-dispersed silica sol to obtain a surface-treated methanol-dispersed silica sol. This sol is then desolvated under reduced pressure and dried to obtain silica powder, which is then dispersed in methyl ethyl ketone. Japanese Patent Publication No. 2011-213514International Publication No. 2014/188934 The present invention relates to a surface-treated silica particle dispersion comprising surface-treated silica particles having an aryl group (Ar) and an alkyl group (R) on the particle surface, a dispersion medium selected from the group consisting of an ether ester solvent, an ester solvent, and an aromatic hydrocarbon solvent, and an alcohol solvent, wherein the content of the alcohol solvent in 100% by mass of the surface-treated silica particle dispersion is 0.20 to 5% by mass (hereinafter sometimes simply referred to as "dispersion"). 1. Surface-treated silica particles The surface-treated silica particles in this invention have an aryl group (Ar) and an alkyl group (R) on their surface, and the surface is hydrophobic. The aryl group is sterically bulky, and even if surface treatment is performed with an amount of aryl group that is theoretically sufficient to completely cover the silica particles, the reaction rate is poor, making it difficult to impart the desired hydrophobicity. However, by having the alkyl group (R) present on the silica particle surface together with the aryl group (Ar), the particle surface becomes highly hydrophobic. The aryl group Ar may be a phenyl group substituted with an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 1 to 4 carbon atoms. Preferably, it is a phenyl group substituted with an alkyl group having 1 to 2 carbon atoms or an alkenyl group having 1 to 2 carbon atoms (such as a phenyl group, tolyl group, dimethylphenyl group, ethylphenyl group, styryl group, etc.), and more preferably a phenyl group. The aryl group Ar on the silica particle surface is preferably an aryl group directly bonded to a silicon atom. To introduce the aryl group Ar onto the silica particle surface, a surface treatment agent containing the aryl group Ar can be used. A compound in which one silicon atom in a molecule is bonded to an aryl group-containing group and a hydrolyzable group or a hydroxyl group is preferred. The hydrolyzable group refers to a compound that can form a silanol group together with the silicon atom through hydrolysis. Examples of compounds in which one silicon atom is bonded to an aryl group-containing group and a hydrolyzable group include aryl group-containing alkoxysilanes, aryl group-containing chlorosilanes, and aryl group-containing acetoxysilanes. Examples of aryl group-containing alkoxysilanes include N-phenyl-3-aminopropyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane. Examples of aryl group-containing chlorosilanes include phenyltrichlorosilane, diphenyldichlorosilane, and methyldiphenylchlorosilane. Examples of aryl group-containing acetoxysilanes include phenyltriacetoxysilane and diphenyldiacetoxysilane. Examples of compounds in which an aryl group-containing group and a hydroxyl group are bonded to one silicon atom in a single molecule include diphenylsilanediols. Among these, aryl group-containing alkoxysilanes are preferred, arylalkoxysilanes in which an aryl group and an alkoxy group are directly bonded to one silicon atom are more preferred, aryltrialalkoxysilanes are even more preferred, and aryltrimethoxysilanes or aryltriethoxysilanes are particularly preferred. For example, if the aryl group Ar is a phen