JPH0699136B2 - Hydrophobized inorganic particles - Google Patents

Description

TECHNICAL FIELD The present invention relates to hydrophobized inorganic particles having excellent hydrophobicity and coloring resistance. In particular, it is a hydrophobized inorganic particle capable of imparting extremely good coloring resistance to the obtained cured product when used as a filler by mixing with a polymerizable monomer.

[Prior Art] When forming a composite material with an organic polymer compound such as a conventional polymer, a hydrophobic treatment is performed to increase the affinity between the inorganic particles and the organic polymer compound and to increase the strength of the obtained composite material. Was generally done. For example, in order to improve the strength of a cured product obtained by filling a dental cavity filler containing a polymerizable monomer, inorganic particles and a polymerization initiator into a cavity of a tooth and curing the same, the surface of the inorganic particles is treated with silane. Treatment with a hydrophobizing agent such as a coupling agent has been performed.

[Problems to be Solved by the Invention] However, the inorganic particles treated with the above-mentioned hydrophobized particles have a coloring substance contacted with the coloring solution so that the surface of the inorganic particles is contacted with the coloring solution even when imparting sufficient hydrophobicity. The phenomenon of being adsorbed by In particular, when the inorganic particles are mixed with a polymerized monomer and used as the dental filler, a coloring substance derived from food ingested in the oral cavity is used as the inorganic particles of the cured body filled in the restoration part. Not only stick to the surface,
There has been a problem that the cured product is colored when it penetrates into the interface between the inorganic particles and the polymer forming the matrix of the cured product.

[Means for Solving Problems] In view of the above problems, the inventors of the present invention have conducted research to develop hydrophobic inorganic particles that are less colored by contact with a coloring solution, that is, have excellent coloring resistance. It was As a result, on the surface of the inorganic particles, a specific silane coupling agent having a polymerizable group as a hydrophobic group and having a long main chain, and a specific silane coupling agent having a short main chain as a hydrophobic group Hydrophobized inorganic particles in which are combined together have excellent hydrophobicity and resistance to discoloration, and are good even in a composite obtained by curing a composition composed of the polymerizable monomer. The present invention has been completed by discovering that it can provide excellent discoloration resistance.

That is, the present invention has the general formula _{A-B-Si- (X 1} ) 3 [wherein A represents a vinyl group or an isopropenyl group, B is a divalent bonded at least 2 atoms in a linear Functional group,
X ₁ represents an alkoxyl group or a halogen atom. Long-chain silane coupling agent of the general formula R-Si- (X _{2) 3} [wherein R is number of carbon atoms in the main chain 3 an alkyl group represented by], alkenyl or phenyl group, a cyclohexyl group, X ₂ represents an alkoxyl group or a halogen atom. ] A short-chain silane coupling agent represented by the following is a hydrophobic inorganic particle formed by bonding to the surface of the inorganic particle.

In the present invention, the inorganic particles are not particularly limited, but representative examples include silica, quartz, titania, alumina, zirconia, iron oxide, zinc oxide, inorganic oxides such as thorium oxide, Examples thereof include inorganic composite oxides such as silica-titania, silica-alumina, silica-zirconia and silica-yttria, and inorganic nitrides such as silicon nitride, titanium nitride, zirconium nitride, aluminum nitride and boron nitride. The shape and size of the above-mentioned inorganic particles are not particularly limited. For example, as a shape, a spherical shape, an amorphous shape, etc. are generally used. Further, the size may be appropriately determined according to the application. In particular,
In the case of the dental filler prepared by mixing the polymerizable monomer and the inorganic particles, those having a particle size of 0.1 to 50 μm are preferable.

In the present invention, the long-chain silane coupling agent has the general formula A
Represented by _{-B-Si- (X 1) 3} . In the above general formula, B, which is a divalent functional group in which at least two atoms are linearly bonded, may have at least two atoms linearly bonded, but is preferably A straight chain bond of 4 to 20 atoms is preferred. Further, the above-mentioned atom is generally a carbon atom, but may be an atom other than a carbon atom, for example, an oxygen atom, a sulfur atom, a nitrogen atom and the like. Atoms other than such carbon atoms are preferably present adjacent to each other between carbon atoms. Further, X ₁ in the above formula is an alkoxyl group or a halogen atom, of which an alkoxyl group is particularly preferable. The above alkoxyl group is -OR '(provided that R'
Represents an alkyl group), and R ′ has 1 to 4 carbon atoms.
Are preferred. Also, halogen atoms are Cl, Br, I
Etc. are common, and Cl is particularly preferable.

Examples of the long-chain silane coupling agent used in the present invention include the following compounds.

CH ₂ = CH (CH ₂ ) ₂ Si (OCH ₃ ) ₃ CH ₂ = CCH ₃ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ CH ₂ = CH (CH ₂ ) ₃ Si (OCH ₃ ) ₃ CH ₂ = CCH ₃ (CH ₂ ) ₃ Si (OCH ₃ ) ₃ CH ₂ = CH (CH ₂ ) ₄ Si (OCH ₃ ) ₃ CH ₂ = CCH ₃ (CH ₂ ) ₄ Si (OCH ₃ ) ₃ CH ₂ = CHCH ₂ (CH ₂ ) ₃ Si (OCH ₃ ) ₃ CH ₂ = CCH ₃ COO (CH ₂ ) ₄ Si (OCH ₃ ) ₃ CH ₂ = CHOCH ₂ CH ₂ OCH ₂ CH ₂ Si (OCH ₃ ) ₃ CH ₂ = CCH ₃ COO (CH ₂ ) ₅ Si (OCH ₃ ) ₃ CH ₂ = CCH ₃ COO (CH ₂ ) ₆ Si (OCH ₃ ) ₃ CH ₂ = CCH ₃ COO (CH ₂ ) ₇ Si (OCH ₃ ) ₃ CH ₂ = CCH ₃ COO (CH ₂ ) ₈ Si (OCH ₃ ) ₃ CH ₂ = CCH ₃ COO (CH ₂ ) ₉ Si (OCH ₃ ) ₃ CH ₂ = CCH ₃ COO (CH ₂ ) ₁₀ Si (OCH ₃ ) ₃ CH ₂ = CCH ₃ COOCH ₂ CHOHCH ₂ NCH ₃ (CH ₂ ) ₃ Si (OCH ₃ ) ₃ CH ₂ = CHS (CH ₂ ) ₂ OCH ₂ CHOHCH ₂ O (CH ₂ ) ₃ Si (OCH ₃ ) _{3 The} short-chain silane coupling agent used in the present invention is generally represented by the formula _{R-Si- (X 2) 3} . X ₂ in the above formula is
The same alkoxyl group or halogen atom as X ₁ is selected without particular limitation. Examples of typical short chain hydrophobizing agents include the following compounds.

CH ₃ Si (OCH ₃ ) ₃ CH ₃ CH ₂ Si (OCH ₃ ) ₃ CH ₃ CH ₂ CH ₂ Si (OCH ₃ ) ₃ CH ₂ = CHSi (OCH ₃ ) ₃ CH ₂ CHCH ₂ Si (OCH ₃ ) ₃ The above long-chain silane coupling agents and short-chain silane coupling agents may be used either individually or in combination of two or more. 0.31 × 10 ^-5 mol / m ² per ² ~
A range of 2.5 × 10 ^-5 mol / m ² is preferable, and 0.5 × 10 ^-5 mo
The range of l / m ^{2 to} 1.3 × 10 ⁻⁵ mol / m ² is more preferable. If the bonding amount is less than this range, the surface of the inorganic particles is not sufficiently covered, and if the bonding amount is more than this range, the mechanical strength of the composite material tends to decrease.

The amount of the short-chain silane coupling agent bound is preferably 5 to 50 mol%, and more preferably 10 to 40 mol% with respect to the amount of the long-chain silane coupling agent bound. The substantial treatment amount of the long-chain silane coupling agent is based on the amount corresponding to the above binding amount, and the amount lost during the treatment may be appropriately added. In this case, 0.3 × 10 ⁻⁵ mol / m ² to 3.0 × 10 ^-5 mol /
Good m ² range. Further, the treatment amount of the short-chain silane coupling agent is preferably in the range of 5 to 100 mol% with respect to the treatment amount of the long-chain silane coupling agent.

Furthermore, it is preferable that the difference in the number of atoms forming the main chain between the long-chain silane coupling agent and the short-chain silane coupling agent is 3 or more.

In the present invention, the method for producing the above-mentioned hydrophobized inorganic particles is not particularly limited. As a representative method, the following method for producing a hydrophobized inorganic material can be preferably applied.

That is, according to the present invention, the general formula _{A-B-Si- (X 1} ) 3 [where wherein A is a vinyl group or an isopropenyl group, B is attached are two atoms in a linear A divalent functional group, X ₁ represents an alkoxyl group or a halogen atom. ] And a long-chain silane coupling agent represented by the general formula R-Si- (X _{2) 3} [The number of carbon atoms of the formula R is the backbone of 3 or less alkyl group or an alkenyl group, a phenyl group or, A cyclohexyl group and X ₂ represent an alkoxyl group or a halogen atom. ] The surface of an inorganic substance is made hydrophobic by the short-chain silane coupling agent represented by these, and the manufacturing method of the hydrophobicized inorganic substance is provided.

The reaction between the silane coupling agent and the inorganic substance in the present invention is carried out by bringing them into contact with each other in the presence of an inert organic solvent. Such inert solvents are generally alcoholic solvents such as methanol, n-propanol, isopropanol, n-butanol and isobutanol, acetone having a carbonyl group such as methyl ethyl ketone, solvents having an ether group such as ethyl ether and dioxane. Solvents having ester groups such as methyl formate and ethyl acetate, solvents containing halogen elements such as methylene chloride, chloroform, carbon tetrachloride, pentane, aliphatic solvents such as n-hexane, cyclohexane and heptane, or benzene, xylene and the like. Aromatic solvents and the like,
In the present invention, one or more of these solvents may be appropriately selected and used. The amount of the solvent used is not particularly limited as long as the surface of the inorganic material can be sufficiently contacted with the inert solvent. Generally, when the inorganic substance is inorganic particles, it is preferable to use the inorganic particles in an amount of 200 to 2000 parts by weight based on 100 parts by weight of the inorganic particles from the viewpoint of dispersibility of the inorganic particles and easy removal of the solvent.

The contact conditions between the silane coupling agent and the inorganic particles,
Although it may be appropriately determined, a temperature from room temperature to the boiling point of the solvent or lower is generally used.

Further, better results are obtained by contacting the surface of the inorganic particles with a primary or secondary aliphatic amine before contacting the silane coupling agent with the inorganic particles. The contact with the aliphatic amine may be carried out directly or in the above-mentioned inert solvent, and the amount of the amine used is 0.1 to 10 times mol, preferably 0.5 to 5 times mol of the hydrophobizing agent. Is. Drying of the inorganic particles reacted with the hydrophobizing agent, if necessary, a filter, a centrifuge, an evaporator and the like to separate the inert solvent, 50 ~ 200 ℃, preferably 80 ~ 1
Drying under reduced pressure, air drying, atmospheric pressure drying or the like may be performed at a temperature of 50 ° C.

The above-described method for producing a hydrophobized inorganic material is applicable not only to inorganic particles but also to inorganic molded articles such as an inorganic plate and an inorganic rod.

When the hydrophobized inorganic particles of the present invention are mixed with a polymerizable monomer to form a curable composition, the curable composition can be cured to effectively improve the coloring resistance of the cured product.
Such polymerizable monomer is not particularly limited,
Those which can be polymerized by heat or light can be used without limitation. The specific examples of the polymerizable monomer are as follows.

A) Monofunctional monomers Methyl methacrylate; Ethyl methacrylate; Hydroxyethyl methacrylate; Tetrahydrofurfuryl methacrylate; Glycidyl methacrylate; and their acrylates or acrylic acid, methacrylic acid, p
-Methacryloxybenzoic acid, N-2-hydroxy-3-
Methacryloxypropyl-N-phenylglycine, 4-
Methacryloxyethyl trimellitic acid and its anhydride,
6-methacryloxyhexamethylenemalonic acid, 10-methacryloxydecamethylenemalonic acid, 2-methacryloxyethylhydrogen phosphate, 10-methacryloxydecamethylenedihydrogenphosphate, 2-hydroxyethylhydrogenphenylphosphate.

(B) Bifunctional monomer (1) Aromatic compound-based 2,2-bis (methacryloxyphenyl) propane; 2,2-
Bis [4- (3-methacryloxy) -2-hydroxypropoxyphenyl] propane; 2,2-bis (4-methacryloxyethoxyphenyl) propane; 2,2-bis (4-methoxydiethoxyphenyl) propane; 2, 2-bis (4-
Methacryloxytetraethoxyphenyl) propane; 2,2
-Bis (4-methacryloxypentaethoxyphenyl)
Propane; 2,2-bis (4-methacryloxydipropoxyphenyl) propane; 2 (4-methacryloxyethoxyphenyl) -2 (4-methacryloxydiethoxyphenyl) propane; 2 (4-methacryloxydiethoxyphenyl) -2 (4-methacryloxyethoxyphenyl) propane; 2 (4-methacryloxypropoxyphenyl) -2
-(4-methacryloxytriethoxyphenyl) propane; 2,2-bis (4-methacryloxypropoxyphenyl) propane; 2,2-bis (4-methacryloxyisopropoxyphenyl) propane and acrylates thereof; 2
-Hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, or vinyl monomers having an -OH group such as acrylates thereof, and diisocyanate methylbenzene, 4,4'-diphenylmethane diisocyanate, etc. Obtained from addition with a diisocyanate compound having an aromatic group (2) Aliphatic compound type ethylene glycol dimethacrylate; diethylene glycol dimethacrylate; triethylene glycol dimethacrylate; butylene glycol dimethacrylate;
Neopentyl glycol dimethacrylate; propylene glycol dimethacrylate; 1,3-butanediol dimethacrylate; 1,6-hexanediol dimethacrylate and their acrylates; 2-hydroxyethyl methacrylate; 2-hydroxypropyl methacrylate,
A vinyl monomer having an —OH group such as 3-chloro-2-hydroxypropyl methacrylate or these acrylates and a diisocyanate compound such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diisocyanate methylcyclohexane, and methylenebis (4-cyclohexyl isocyanate). Diacduct obtained from the addition of; acrylic acid anhydride, methacrylic acid anhydride; 1,2-bis (3-methacryloxy-2-hydroxypropoxy) ethyl, di (2-methacryloxyethyl) phosphate, di (3-methacryloxypropyl) ) Phosphate (c) Trifunctional monomer Trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, pentaerythritol trimethacrylate , Trimethylolmethane trimethacrylate (d) tetrafunctional monomer pentaerythritol tetramethacrylate, pentaerythritol tetraacrylate and diisocyanate methylbenzene, diisocyanate methylcyclohexane, isophorone diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, methylenebis (4- Cyclohexylisocyanate), 4,4-diphenylmethane diisocyanate, dilenide obtained from addition of diisocyanate compound such as tolylene-2,4-diisocyanate and glycidol dimethacrylate In addition to the above vinyl monomers, those generally known for industrial use can be used. . Examples of typical ones that are generally suitably used include vinyl acetates such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether and isobutyl vinyl ether; styrene, vinyltoluene, α-methylstyrene, Alkenylbenzenes such as chloromethylstyrene and stilbenzene are preferably used.

When using a plurality of types of polymerizable monomers, when the polymerizable monomer has an extremely high viscosity at room temperature or is a solid, it is preferable to use it in combination with a low-viscosity polymerizable monomer. preferable. This combination is not limited to two types and may be three or more types.

When a monofunctional monomer is used among the above polymerizable monomers, it is preferably used together with a polyfunctional monomer.

The polymerization initiator used in the present invention is not particularly limited, and known ones can be adopted without limitation. A known addition range is adopted as the addition amount.

Generally, the polymerization initiator varies depending on the means of polymerizing the polymerizable monomer. This polymerization means includes light energy such as ultraviolet rays and visible light, heating, and reaction between a peroxide and a polymerization accelerator. The polymerization means can be selected as necessary. For example, in the case of a reaction by light energy (hereinafter referred to as photopolymerization), camphorquinone, benzyl, α-naphthyl, a polymerization initiator,
Acetobutenequinone, P, P'-dimethoxybenzyl, 4
-Nitrobenzyl, hexadione, cyclohexadione, P, P'-dichlorobenzyl, biacetyl, pentanedione, 1,2-phenanthrenequinone, 3,4-phenanthrenequinone, 9,8-phenanthrenequinone β-naphthoquinone α- Known as diketone compounds, α-diketone compounds and tertiary amines, α-diketone compounds and tertiary amines, and carboxylic acids having an oxy group at the α-position, α-diketone compounds and α-diketones of phosphite compounds. The combination with the reducing agent is preferable. In this case, the weight ratio of α-diketone / reducing agent is preferably 10/90 to 60/40. The blending amount of the above-mentioned polymerization initiator is selected without any particular limitation. Generally, 0.01 to 5% by weight with respect to the polymerizable monomer
Used in proportion.

In the case of thermal polymerization, as a polymerization initiator, for example,
Organic peroxides such as benzoyl peroxide, di-p-chlorobenzoyl peroxide and dilauroyl peroxide, 2,2′-azobisisobutyronitrile, 4,4 ′
Known polymerization initiators such as azo compounds such as -azobis (4-cyanovaleric acid) and 2,2'-azobis (2,4-dimethylvaleronitrile) can be used. The compounding amount of the above-mentioned polymerization initiator is selected without any particular limitation, which is usually adopted. Generally, it is used in a proportion of 0.01 to 5% by weight with respect to the polymerizable monomer.

[Effect of the present invention] The hydrophobized inorganic particles of the present invention and the hydrophobized inorganic molded article obtained by the method of the present invention are very excellent in hydrophobicity,
Moreover, the active sites are completely covered and are chemically safe, so that they have excellent coloring resistance.

In particular, when the hydrophobicized inorganic particles are mixed with a polymerizable monomer and used as a curable composition, the hydrophobicized inorganic particles exhibit an effect of significantly improving the discoloration resistance of the cured product.

[Examples] In order to describe the present invention more specifically, examples will be described below, but the present invention is not limited to these examples. The water repellency and discoloration resistance of the surface-treated particles shown in Examples and Comparative Examples, or the amount of the hydrophobizing agent bound was determined by the method described below.

(1) Water repellency The strength of water repellency can be determined from the height of the contact angle with water.

1.0 g of the surface-treated particles were molded into a disk shape by a tablet molding machine, 50 μl of distilled water was added dropwise thereto, and the value after 3 minutes was measured using a contact angle measuring device.

(2) Coloring resistance test The coloring resistance of the surface-treated particles was evaluated by immersing the particles in a 7.4% coffee solution at 37 ° C for 24 hours and evaluating the degree of coloring according to the following criteria.

◯: Little coloring Δ: Many coloring ×: Significant coloring Further, the coloring resistance test of the cured product was performed according to the following method.

Inorganic particles 70 parts by weight bis-GMA 18 〃 TEGDMA 12 〃 AIBN 0.15 〃 The paste prepared with the above composition ratio was heat-polymerized under an atmosphere of 4 atm N ₂ and the resulting cured product was added to a 7.4% coffee solution.
It was immersed at 24 ° C. for 24 hours, and the amount of discoloration before and after immersion was measured using a color difference meter manufactured by Nippon Denshoku Co., Ltd.

Incidentally, bis-GMA, TEGDMA, and AIBN are 2,2-bis (4- (3-methacryloxy) propoxyphenyl) propane triethylene glycol diacrylate and 2,2-bis, respectively.
Abbreviation for azobisisobutyronitrile.

(3) Method for measuring the amount of silane coupling agent bound The surface-treated particles were dispersed in a methanol solution adjusted to pH 12 with an aqueous potassium hydroxide solution, and refluxed for 48 hours. Next, this solution was filtered to separate the inorganic particles and the solvent. After washing with methanol several times, the recovered solvent was neutralized with hydrochloric acid and concentrated, and then the hydrophobic group of the hydrophobizing agent in the solution was identified and quantified by H-NMR.

Examples 1 to 3 Tetraethyl silicate (Nippon Colcoat) 1600 g
Dissolve 54 g of 0.05% sulfuric acid in 2.0 l of isobutanol
After stirring for a period of time to partially hydrolyze, 650 g of tetrabutyl zirconate and 77 g of sodium methylate were added, and the mixture was stirred for 1 hour and then 0.3 l of water was added for further hydrolysis to obtain a gel. Next, the gel was taken out and dried by heating at 100 ° C. to remove the solvent, and a dried gel was obtained. The dried gel was ground with a ball mill. The pulverized product was calcined at 900 ° C. for 2 hours to obtain a white powder. This white powder was an indeterminate inorganic powder composed of a composite oxide of zirconia, silica, and sodium oxide, which partially contained tetragonal zirconia crystals from X-ray diffraction and fluorescent X-ray diffraction.

Obtained inorganic powder, particle size 0.5 to 50 μm, average particle size 5 μm BET
The specific surface area by the method was 3 m ² . 10 g of this complex oxide powder was added to 100 ml of isopropyl alcohol and dispersed by a stirrer, 0.1 ml of n-propylamine was added, and the mixture was further stirred for 30 minutes. As a long-chain hydrophobizing agent, γ-
Methacryloxypropyltrimethoxysilane and methylmethoxysilane as a short chain hydrophobizing agent were added. After stirring for 1 hour and removing the solvent with an evaporator,
Surface-modified inorganic oxide powder was obtained by drying under reduced pressure for an hour. The treatment amount of the hydrophobizing agent per 1 m ^{2 of} surface area of the inorganic particles is shown in Table 1.

Comparative Examples 1 to 3 In Comparative Examples 1 and 2, each of γ-methacryloxypropyltrimethoxysilane and methylmethoxysilane was treated alone, and in Comparative Example 3, γ-methacryloxypropyltrimethoxysilane was compared to Comparative Example 1. It was treated with a 3-fold molar amount. The surface treatment method was the same as in Example 1. Examples 1-3
The results of Comparative Examples 1 to 3 are shown in Table 1.

As shown in Examples 1 to 3 in Table 1, the system in which the short-chain hydrophobizing agent is bound to the long-chain hydrophobizing agent in the range of 10 to 40 mol% is a long-chain hydrophobizing agent and a short-chain hydrophobizing agent. The discoloration resistance was remarkably improved as compared with the system using the agent alone (Comparative Examples 1 and 2) and the system using the long-chain hydrophobizing agent in excess (Comparative Example 3).

Examples 4 to 6 5.0 g of 0.04% hydrochloric acid and 142.0 g of tetraethyl silicate (manufactured by Nippon Corcoat) were dissolved in 0.44 l of methanol, and this solution was hydrolyzed at 30 ° C. for about 1 hour with stirring. After that, add tetrabutyl titanate (Nippon Soda Co., Ltd.) 3
A solution prepared by dissolving 7.7 g in a mixed solution of 0.25 l of methanol and 0.39 l of isopropanol was added with stirring to prepare a mixed solution with tetrabutyl titanate. Next, 0.75 liters of methanol and 1.13 liters of isobutyl alcohol were introduced into a glass reaction vessel with an internal volume of 3 liters equipped with a stirrer, and an aqueous ammonia solution of 0.41 (concentration 25 wt%) was added to this to prepare an ammoniacal alcohol solution. Tetraethyl silicate as an organosilicon compound solution for making silica seeds
A solution prepared by dissolving 3.0 g in 30 ml of methanol was added, and 10 minutes after the addition was completed, when the reaction liquid became slightly milky, the above mixed solution was continuously added over about 5 hours.
Next, 108.0 g of tetraethyl silicate and 3.3 g of sodium methylate were dissolved in 0.75 l of methanol, and this solution was added over about 3 hours to precipitate a reaction product. The temperature of the reaction vessel was kept at 20 ° C during the reaction. After completion of the reaction, stirring was continued for another 30 minutes, then the solvent was removed from the milky white reaction solution by an evaporator, and further dried under reduced pressure at 80 ° C. to obtain a milky white powder. Next, this powder is 900 ℃, 1
Firing was carried out for a time to obtain a spherical composite oxide powder composed of silica, titania and sodium oxide.

The obtained powder had an average particle diameter of 0.23 μm and a BET specific surface area of 16 m ² / g.

10 g of this complex oxide powder was added to 100 ml of ethyl alcohol and dispersed with a stirrer, then n-propylamine 0.2 m
l was added and stirred for another 30 minutes. To this solution, γ-methacryloxypropyltrimethoxysilane as a long-chain hydrophobizing agent and methyltrimethoxysilane as a short-chain hydrophobizing agent were added in the amounts shown in Table 2. After further stirring for 1 hour, the solvent was removed by an evaporator, and dried under reduced pressure at 80 ° C for 15 hours.

The obtained surface-treated powder was examined for hydrophobicity and discoloration resistance in the same manner as in Examples 1 to 4.

The results are shown in Table 2. Similar to Examples 1 to 3, the surface of the silica-titania-based composite oxide particles was completely covered, and the discoloration resistance and water repellency were good.

Example 7 A long-chain silane coupling agent, ε-methacryloxypentyltrimethoxysilane, was added to 1 g of the inorganic particles used in Example 3 at 8.5 × 10 ⁻⁵ mol / g (5.3 × 10 ⁻⁶ mol / m ² ). , Short-chain silane coupling agent, phenyltrimethoxysilane 2.0 × 1
An amount of 0 ⁻⁵ mol / g (1.6 × 10 ⁻⁶ mol / m ² ) was applied. The surface treatment method was the same as in Example 4.

Example 8 To 1 g of the inorganic particles used in Example 3, a long-chain silane coupling agent ε-methacryloxypentyltrimethoxysilane was added at 8.5 × 10 ⁻⁵ mol / g (5.3 × 10 ⁻⁶ mol / m ² ), Short-chain silane coupling agent, cyclohexyltrimethoxysilane
An amount of 2.0 × 10 ⁻⁵ mol / g (1.6 × 10 ⁻⁶ mol / m ² ) was applied. The surface treatment method was the same as in Example 4.

Example 9 A long-chain hydrophobizing agent, κ-, was added to 1 g of the stem particles used in Example 3.
Methacryloxyoctyltrimethoxysilane 8.5 × 10
^-5 mol / g (5.3 × 10 ^-6 mol / m ² ), short-chain hydrophobizing agent, vinyltrimethoxysilane at 2.0 × 10 ^-5 mol / g (1.6 × 10 ^-6 mol / m ² ).
m ² ) processed. The surface treatment method was the same as in Example 4.

Example 10 ε-methacryloxypentyltrimethoxysilane as a long-chain hydrophobizing agent for 1 g of the inorganic particles used in Example 3.
2 × 10 ^-5 mol / g (2.6 × 10 ^-6 mol / m ² ), γ-methacryloxypropyltrimethoxysilane 4.2 × 10 ^-5 mol / g (2.6 × 1
0 ^-6 mol / m ^2), short-chain vinyl silane and ^{2.2 × 10 -5 mol / g (} 1.4 × 10 -6 mol / m 2 as a hydrophobizing agent) was treated amount.
The surface treatment method was the same as in Example 4.

Comparative Examples 6 and 7 In Comparative Example 4, with respect to 1 g of the inorganic particles used in Example 3, γ-methacryloxypropyltrimethoxysilane was used as a long-chain hydrophobizing agent at 8.5 × 10 ⁻⁵ mol / g (5.3 × 10 ^-6 mol / m ² ),
Pentiltrimethoxysilane as a short-chain hydrophobizing agent 2.
0 × 10 ⁻⁵ mol / g (1.3 × 10 ⁻⁶ mol / m ² ). In Comparative Example 5, octyltrimethoxysilane was used as a long-chain hydrophobizing agent at 2.0 × 1.
0 ^-5 mol / g (1.3 × 10 ^-6 mol / m ² ) 1.4 × 10 ^-6 mol / g (0.8 × 10 ^-6 mol) methyltrimethoxysilane as a short-chain hydrophobizing agent.
/ m ² ) processed. The surface treatment method was the same as in Example 4.

Table 3 shows the results of Examples 7 to 10 and Comparative Examples 6 and 7.

As described above, good discoloration resistance was exhibited in a combination of a hydrophobizing agent having a hydrophobic main chain length of 4 or more and a hydrophobizing agent of 3 or less. In the combination with the long-chain hydrophobizing agent which does not have, discoloration resistance decreased.

Claims (2)

[Claims] 1. A general formula AB-Si- (X ₁ ) ₃ [wherein A is a vinyl group or an isopropenyl group, and B is a divalent functional group in which at least two atoms are linearly bonded. The group X ₁ represents an alkoxyl group or a halogen atom. ] And a long-chain silane coupling agent represented by the general formula R-Si- (X _{2) 3} wherein R
Represents an alkyl group, alkenyl group or phenyl group having a carbon number of 3 or less in the main chain, a cyclohexyl group, and X ₂ represents an alkoxyl group or a halogen atom. ] Hydrophobicized inorganic particles obtained by bonding a short-chain silane coupling agent represented by the following to the surface of the inorganic particles. 2. The general formula AB-Si- (X ₁ ) ₃ [wherein A is a vinyl group or an isopropenyl group, and B is a divalent group in which at least two atoms are linearly bonded. And a functional group, X ₁ is an alkoxyl group or a halogen atom. Formula and long-chain silane coupling agent represented by] R-Si- (X _{2) 3} [The number of carbon atoms of the formula R is the backbone of 3 or less alkyl group or an alkenyl group, a phenyl group or a cyclohexyl group , X ₂
Represents an alkoxyl group or a halogen atom. ] The surface of the inorganic material is hydrophobized with a short-chain silane coupling agent represented by the following.