JP4510437B2 - Metal oxide particles and method for producing the same - Google Patents

Description

  The present invention relates to metal oxide particles having high hydrophobicity.

  In recent years, the usefulness and applicability of metal oxide particles including silica have been recognized in various industrial fields. In general, since the surface of the metal oxide particles is hydrophilic due to the presence of a large number of hydroxyl groups, aggregation of the metal oxide particles occurs severely in a nonpolar solvent. Therefore, attempts have been made to make the surface of metal oxide particles hydrophobic by various methods.

Examples of metal oxide particles whose surfaces have been hydrophobized by chemical reaction include, for example, silica particles obtained by hydrophobizing the surface of dry silica using chlorosilane or silazane, and the surface of silica derived from water glass is treated with dimethyl groups. Known silica particles, silica particles hydrophobized by combining silane coupling agent treatment and chlorosilane treatment, silica particles obtained by forcibly performing a sol-gel reaction in the presence of a nonpolar solvent and alcohol, etc. are known. (For example, see Patent Documents 1, 2, 3, and 4).
On the other hand, as the metal oxide particles whose surface is hydrophobized by physical coating, for example, the core-shell type silica particles coated with vinyl polymer after the silane coupling agent treatment, the surface is coated with polyorganosiloxane containing aromatic groups Silica particles are known (see, for example, Patent Documents 5 and 6).

  However, all the metal oxide particles whose surface has been hydrophobized by the above chemical reaction are strongly agglomerated in a nonpolar solvent having a polarity lower than that of methyl ethyl ketone, that is, an ε value of less than 15. In addition, any metal oxide particles whose surface has been hydrophobized by physical coating are easily desorbed by mixing with the nonpolar solvent to cause aggregation.

  Thus, silica particles obtained by refluxing after adding a silicone compound in a solvent in which silica particles are dispersed have been proposed as silica particles whose surface hydrophobization rate can be adjusted (for example, Patent Document 7). reference).

Japanese Patent Laid-Open No. 7-10524 JP 11-43319 A Special table 2003-507557 gazette JP-A-6-92621 JP-A-9-194208 JP 2003-128837 A JP 2003-201114 A

However, although the silica particles are relatively dispersed in the nonpolar solvent, they cannot be dispersed in the form of primary particles, and the hydrophobicity is not sufficient. In order to obtain sufficient hydrophobicity, it is necessary to use a silicone compound having an alkyl group having a long chain length. In this case, however, the reactivity of the silicone compound is lowered, and the hydrophobicity of the surface is inevitably lowered. There was a problem that.
Thus, metal oxide particles such as silica cannot be said to have insufficient dispersion stability in a nonpolar solvent, and it is extremely difficult to disperse in a nonpolar solvent in the form of primary particles. For example, when trying to combine with a functional material (dye component, rubber compound, etc.) that only dissolves in a nonpolar solvent, it was virtually impossible to uniformly mix in the form of primary particles.

  Accordingly, an object of the present invention is to provide metal oxide particles that are excellent in dispersion stability in a nonpolar solvent.

The inventors of the present invention diligently studied the above-mentioned problems, and chemically modified the surface of the metal oxide particle main body with at least two different types of hydrophobic groups to thereby stabilize dispersion in a nonpolar organic solvent. The present inventors have found that metal oxide particles having excellent properties can be obtained and completed the present invention.
That is, the present invention provides a metal oxide in which at least two different types of hydrophobic groups are chemically bonded to the surface of a metal oxide particle body composed of silica, alumina, titania or a composite thereof via Si atoms. Particles, tetraalkoxysilane, trialkoxyaluminum , tetraalkoxytitanium or a mixture of two or more thereof, and the following general formula (1)
R _n SiX _4-n (1)
(Wherein R represents a hydrophobic group, X represents an alkoxyl group having 1 to 4 carbon atoms or a chlorine atom, and n represents a number of 1 to 3). A silane compound is added to a mixed solvent containing a water-soluble organic solvent, a nonpolar organic solvent and water, and is subjected to hydrolysis and condensation reaction. The ratio of the molecular weight of the total hydrophobic group to the molecular weight of the metal oxide particle body is The metal oxide particles are 20% to 60% and have an average particle diameter of 1 to 100 nm.

  According to the present invention, metal oxide particles having excellent dispersion stability in a nonpolar solvent can be obtained.

In the metal oxide particles of the present invention, at least two different types of hydrophobic groups are chemically bonded to the surface of the metal oxide particles through metal atoms. Metal oxide particle body may be selected depending on the application of the metal oxide particles, e.g., silica _(SiO 2), alumina _{(Al 2 O} 3), include titania (TiO ₂₎ and composites thereof and the like It is done. Among these, those synthesized by a wet method using a metal alkoxy compound are preferable.
In the present invention, the hydrophobic group may be any kind as long as it is different and can hydrophobize the particle surface, but one of the hydrophobic groups is an aliphatic hydrocarbon group and the other is an aromatic group. It is preferably a hydrocarbon group. By using such a combination of hydrophobic groups, the hydrophobicity of the metal oxide particles is greatly improved by the aromatic hydrocarbon groups, and the SiOH groups remaining on the surface of the metal oxide particles by the aliphatic hydrocarbon groups are reduced. Can be blocked.

Preferred as the aliphatic hydrocarbon group is an aliphatic saturated hydrocarbon group, more preferred is an alkyl group having an unsubstituted or non-reactive substituent, and most preferred is a linear or branched chain having 1 to 8 carbon atoms. Of these, a preferred aromatic hydrocarbon group is an aryl group having an unsubstituted or nonreactive substituent, and a more preferred one is a phenyl group having an unsubstituted or nonreactive substituent.
Specific examples of such hydrophobic groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, isopentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl and other alkyl groups; vinyl, propenyl, iso Alkenyl groups such as propenyl, butenyl, isobutenyl, pentenyl, hexenyl; cycloalkyl groups such as cyclopentyl, cyclohexyl, methylcyclohexyl; phenyl, toluyl, xylyl, cumenyl, mesityl, benzyl, phenethyl, styryl, cinnamyl, benzhydryl, trityl, ethylphenyl , Aryl groups such as propylphenyl, butylphenyl and β-naphthyl.

The metal oxide particles of the present invention include, for example, a metal alkoxy compound and a general formula R _n SiX _4-n (1)
(Wherein, R represents a hydrophobic group, X represents an alkoxyl group having 1 to 4 carbon atoms or a chlorine atom, and n represents a number of 1 to 3). It can manufacture by adding a seed | species silane compound to the mixed solvent containing a water-soluble organic solvent, a nonpolar organic solvent, water, etc., and making it hydrolyze and condense.
In the present invention, when the metal alkoxy compound and the silane compound are added to the mixed solvent, they may be added after mixing the metal alkoxy compound and the silane compound, or each may be added separately. . Moreover, you may add in a lump and may add by dividing | segmenting by methods, such as dripping. It is particularly preferable that the metal alkoxy compound is added first and allowed to react to some extent, and then the silane compound is added and further reacted.

  The amount of the metal alkoxy compound added to the mixed solvent and the silane compound represented by the general formula (1) and at least two silane compounds having different hydrophobic groups R is included in the metal alkoxy compound and the silane compound represented by the general formula (1). The ratio of water to the total of alkoxyl groups and chlorine atoms is preferably 0.125 to 2 in terms of molar ratio, more preferably 0.25 to 1.5, and 0.3 to 1 Is most preferred. When the molar ratio is less than 0.125, hydrolysis and condensation reaction may be insufficient. When the molar ratio exceeds 2, the relative ratio of metal oxide particles to the mixed solvent decreases. This is because the productivity of the metal oxide particles may decrease.

  In addition, the amount ratio of the metal alkoxy compound and the at least two silane compounds represented by the general formula (1) and having different hydrophobic groups R is such that the ratio of the molecular weight of the total hydrophobic groups to the molecular weight of the metal oxide particle body is It is preferably 20 to 60%, and more preferably 25 to 45%. When the ratio of the molecular weight of the total hydrophobic group to the molecular weight of the metal oxide particle main body is less than 20%, the dispersion stability of the metal oxide particles in the nonpolar organic solvent may be insufficient. This is because the hydrolysis / condensation reaction may become insufficient when the ratio of the molecular weight of the total hydrophobic group to the molecular weight exceeds 60%.

A metal alkoxy compound M (OR ′) _m represented by Si (OR ′) ₄ (wherein M represents an m-valent metal atom) becomes MO _{m / 2} by hydrolysis. On the other hand, the silane compound R _n SiX _4-n is hydrolyzed to R _n SiO _{(4-n) / 2} .
Therefore, the ratio of the molecular weight of the total hydrophobic group to the molecular weight of the metal oxide particle main body can be calculated by the following equation. In the formula, the number of moles represents the number of moles charged for each compound before hydrolysis.

  When using a silane compound containing a chlorine atom and using an acid catalyst, the reaction temperature for hydrolysis and condensation is preferably 20 to 100 ° C, more preferably 40 to 90 ° C, and more preferably 55 to 80 ° C. Is most preferred. Moreover, when using the silane compound which does not contain a chlorine atom in absence of a catalyst, and when using an alkali metal catalyst or an amine catalyst, 10-70 degreeC is preferable, 10-50 degreeC is still more preferable, 10-30 C is most preferred. When the reaction temperature is lower than this temperature range, the hydrolysis or condensation reaction may be insufficient. When the reaction temperature is higher than this temperature range, the resulting metal oxide particles may easily aggregate. Because there is. The reaction time is preferably 1 to 8 hours, more preferably 1 to 6 hours, and most preferably 1 to 4 hours.

  After completion of the reaction, excess water, hydrochloric acid (generated when X is a chlorine atom), and the like are removed to obtain the metal oxide particles of the present invention. Thereafter, concentration or solvent replacement may be performed as necessary. For example, when toluene is used as the nonpolar organic solvent and ethanol is used as the water-soluble organic solvent, excess water can be removed by removing water and ethanol azeotropically after the reaction is completed. Further, by removing ethanol and concentrating, metal oxide particles dispersed in toluene can be obtained. The solid content of the metal oxide particles of the present invention is preferably 1 to 40% by mass, more preferably 10 to 30% by mass, and most preferably 15 to 25% by mass. If the solid content is less than 1% by mass, the content may be too small when used, and if it exceeds 40% by mass, secondary aggregation of uniformly dispersed metal oxide particles may occur. It is because there is sex.

  Examples of the metal alkoxy compound that can be used in the present invention include tetraalkoxysilane, trialkoxyaluminum, and tetraalkoxytitanium. These may be used alone or in combination of two or more. When using 2 or more types, they may be mixed and may be added separately. Particularly preferred is that tetraalkoxysilane is added first and allowed to react to some extent, then trialkoxyaluminum and / or tetraalkoxytitanium is added, and further reaction is carried out.

  Specific examples of tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, tetraisobutoxysilane, tetrakis (2-methylpropoxy) silane, tetrakispentoxysilane, tetrakis (2-Ethylbutoxy) silane, tetrakis (octoxy) silane, tetrakis (2-ethylhexoxy) silane and the like can be mentioned. If the alkoxyl group contained in the tetraalkoxysilane has too many carbon atoms, hydrolysis may be insufficient. Tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane and tetra Isobutoxysilane is preferred, tetramethoxysilane and tetraethoxysilane are more preferred, and tetraethoxysilane is most preferred.

  Specific examples of trialkoxyaluminum include trimethoxyaluminum, triethoxyaluminum, tripropoxyaluminum, triisopropoxyaluminum, tributoxyaluminum, triisobutoxyaluminum, trikis (2-methylpropoxy) aluminum, trikispentoxyaluminum, trikis (2-ethylbutoxy) aluminum, trikis (octoxy) aluminum, trikis (2-ethylhexoxy) aluminum, etc. are mentioned. If the alkoxyl group contained in the trialkoxyaluminum has too many carbon atoms, hydrolysis may be insufficient. If the alkoxyl group has too few carbon atoms, the reactivity may be high and the reaction control may be difficult. Therefore, triethoxyaluminum, tripropoxyaluminum, triisopropoxyaluminum and tributoxyaluminum are preferred, triethoxyaluminum, tripropoxyaluminum and triisopropoxyaluminum are more preferred, and tripropoxyaluminum and triisopropoxyaluminum are most preferred.

  Specific examples of tetraalkoxytitanium include tetramethoxytitanium, tetraethoxytitanium, tetrapropoxytitanium, tetraisopropoxytitanium, tetrabutoxytitanium, tetraisobutoxytitanium, tetrakis (2-methylpropoxy) titanium, tetrakispentoxytitanium, tetrakis (2-Ethylbutoxy) titanium, tetrakis (octoxy) titanium, tetrakis (2-ethylhexoxy) titanium and the like can be mentioned. If the alkoxyl group contained in the tetraalkoxytitanium has too many carbon atoms, hydrolysis may be insufficient. If the alkoxyl group has too few carbon atoms, the reactivity may increase and the reaction control may be difficult. Therefore, tetraethoxytitanium, tetrapropoxytitanium, tetraisopropoxytitanium, tetrabutoxytitanium and tetraisobutoxytitanium are preferred, tetraethoxytitanium, tetrapropoxytitanium and tetraisopropoxytitanium are more preferred, tetrapropoxytitanium and tetraisopropoxytitanium. Titanium is most preferred.

Specific examples of the silane compound represented by the general formula (1) that can be used in the present invention include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, trimethylethoxysilane, and ethyltrisilane. Methoxysilane, diethyldimethoxysilane, triethylmethoxysilane, ethyltriethoxysilane, diethyldiethoxysilane, triethylethoxysilane, propyltrimethoxysilane, dipropyldimethoxysilane, tripropylmethoxysilane, propyltriethoxysilane, dipropyldiethoxysilane , Tripropylethoxysilane, isobutyltrimethoxysilane, diisobutyldimethoxysilane, triisobutylmethoxysilane, isobutyltrieth Sisilane, diisobutyldiethoxysilane, triisobutylethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, triphenylmethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, triphenylethoxysilane, phenethyltrimethoxysilane, diphenethyldimethoxysilane , Triphenethylmethoxysilane, phenethyltriethoxysilane, diphenethyldiethoxysilane, triphenethylethoxysilane, ethyltrichlorosilane, diethyldichlorosilane, triethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, vinyltrichlorosilane, ethyltrichlorosilane, diethyl Examples include dichlorosilane and triethylchlorosilane.
Among these, ethyltrimethoxysilane, diethyldimethoxysilane, ethyltriethoxysilane, diethyldiethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, phenethyltrimethoxysilane, diphenethyldimethoxy Silane, phenethyltriethoxysilane and diphenethyldiethoxysilane are preferred, ethyltrimethoxysilane, diethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, phenethyltrimethoxysilane and diphenethyldimethoxysilane are more preferred, and ethyltrimethoxysilane. Most preferred are phenyltrimethoxysilane and phenethyltrimethoxysilane.

  In the present invention, when a silane compound containing a chlorine atom is used, more specifically, ethyltrichlorosilane, diethyldichlorosilane, triethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, vinyltrichlorosilane, ethyltrichlorosilane, diethyldisilane. When chlorosilane, triethylchlorosilane or the like is used, hydrochloric acid generated by hydrolysis acts as a catalyst, so that hydrolysis and condensation reactions easily proceed. However, when a silane compound containing no chlorine atom is used, it is preferable to use a catalyst in combination. Examples of catalysts that can be used here include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, acetic acid, oxalic acid, methanesulfonic acid, ethanesulfonic acid, 2-hydroxyethanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, and other acid catalysts. ; Alkali metal catalysts such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate; ammonia, ethylamine, ethylamine, propylamine, butylamine, diethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyrrolidine, piperidine, piperazine And amine catalysts such as morpholine and pyridine. Among these, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, acetic acid, oxalic acid, ammonia, ethylamine, ethylamine, propylamine, butylamine, monoethanolamine are preferred, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, acetic acid and Oxalic acid is more preferred, and hydrochloric acid and phosphoric acid are most preferred. The addition amount of the catalyst is preferably 0.05 to 20 parts by mass, and 0.1 to 5 parts by mass with respect to 100 parts by mass in total of the metal alkoxy compound and the silane compound represented by the general formula (1). More preferably, it is most preferably 0.5 to 2 parts by mass.

(Mixed solvent)
As a mixed solvent, what contains 100 mass parts of water-soluble organic solvents, 50-300 mass parts of nonpolar organic solvents, and 0.1-35 mass parts of water can be used, for example.
When the amount of water contained in the mixed solvent is less than 0.1 parts by mass with respect to 100 parts by mass of the water-soluble organic solvent, productivity may be insufficient. The particle diameter of the metal oxide particles to be increased may cause agglomeration and separation. Preferably, the water contained in the mixed solvent is 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, and most preferably 2 to 10 parts by mass with respect to 100 parts by mass of the water-soluble organic solvent. It is.

  The water-soluble organic solvent used in the mixed solvent may be any organic solvent that is liquid at 25 ° C. and dissolves in water at 25 ° C., for example, water-soluble monohydric alcohols such as methanol, ethanol, propanol, and isopropanol; ethylene Water-soluble polyhydric alcohols such as glycol, propylene glycol, 1,3-butanediol, glycerin; ethylene glycol monoethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, propylene glycol ethyl ether, 3-methoxybutanol, 3 -Water-soluble ether alcohols such as ethyl 3-methoxybutanol; tetrahydrofuran, 1,4-dioxane, ethylene glycol diethyl ether, diethylene glycol diethyl ether, propylene glycol Water-soluble ethers such as ethyl ether; acetonitrile, dimethylformamide, diethyl sulfoxide and the like, may be used in combination alone or two or more. Among these, since fine metal oxide particles can be obtained, water-soluble monohydric alcohols and water-soluble polyhydric alcohols are preferred, water-soluble monohydric alcohols are more preferred, methanol, ethanol and isopropanol are more preferred, and ethanol is preferred. Most preferred.

Examples of the nonpolar organic solvent used in the mixed solvent include saturated aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, isooctane (2,2,4-triethylpentane), nonane and decane; hexene, heptene, Unsaturated aliphatic hydrocarbon solvents such as octene, isooctene, nonene, decene, dodecene; cycloaliphatic carbonization such as cyclopentane, cyclohexane, cyclohexene, cycloheptane, ethylcyclohexane, cyclooctane, diethylcyclohexane, decalin (decahydronaphthalene) Hydrogen solvents; aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, cumene (isopropylbenzene), pseudocumene (triethylbenzene), tetralin (1,2,3,4-tetrahydronaphthalene), etc. That. Among these, an aromatic hydrocarbon solvent is preferable because fine metal oxide particles are obtained and its dispersion stability is good, and toluene, xylene and pseudocumene are more preferable, and toluene is most preferable.
When the nonpolar organic solvent contained in the mixed solvent is less than 50 parts by mass with respect to 100 parts by mass of the water-soluble organic solvent, the dispersion stability of the metal oxide particles in the nonpolar organic solvent may be reduced. When it exceeds 300, the particle diameter of the metal oxide particles to be produced increases, which may cause agglomeration and separation. Preferably, the nonpolar organic solvent is 60 to 250 parts by weight, more preferably 70 to 200 parts by weight, and most preferably 80 to 150 parts by weight with respect to 100 parts by weight of the water-soluble organic solvent.

Moreover, it is preferable that the water-soluble organic solvent, the nonpolar organic solvent, and water in the mixed solvent are uniformly dissolved or dispersed. If not uniformly dissolved or dispersed, the dispersion stability of the metal oxide particles in the nonpolar organic solvent may be insufficient.
In the present invention, the state in which the water-soluble organic solvent, nonpolar organic solvent and water in the mixed solvent are uniformly dissolved or dispersed is that the mixed solvent is visually transparent or mixed without being separated into two layers. A state in which the solvent is stably emulsified.
Such a mixed solvent can be prepared by sufficiently mixing a water-soluble organic solvent, a nonpolar organic solvent, and water by stirring or the like. The method of mixing the water-soluble organic solvent, the nonpolar organic solvent and water is arbitrary, and can be performed, for example, by stirring with a blade-type stirrer. The mixing order is also arbitrary, but it is preferable to add a nonpolar organic solvent after mixing the water-soluble organic solvent and water, so that it becomes uniform easily.

  Moreover, you may introduce | transduce a reactive group into the metal oxide particle of this invention by making the alkoxysilane compound which has a reactive group react further. Examples of such reactive groups include hydroxyl groups such as 2-hydroxyethyl, 3-hydroxypropyl, 3- (2-hydroxyethoxy) propyl, N, N-bis (2-hydroxyethyl) -3-aminopropyl, and the like. Radicals such as vinyl, 3-acryloxypropyl and 3-methacryloxypropyl; epoxy groups such as 3-glycidoxypropyl and 2- (3,4-epoxycyclohexyl) ethyl; 2-aminoethyl, 3-aminopropyl, N-ethyl 3-aminopropyl, 2-aminoisopropyl, 4-aminobutyl, N-cyclohexylaminoethyl, N- (2-aminoethyl) -3-aminopropyl, 3- (4-ethylpipe) Razinyl) propyl, amino groups such as 6-aminohexylaminoethyl; Mercapto group, and the like.

Specific examples of the alkoxysilane compound having such a reactive group include 3-hydroxypropyltrimethoxysilane, bis (3-hydroxypropyl) dimethoxysilane, vinyltris (3-methoxyethoxy) silane, and 3-methacryloxypropylethyl. Dimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxy Propyltrimethoxysilane, 3-glycidoxypropylethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3- {N- (2-aminoethyl)} aminopropyltrimethoxysilane, 3- {N- 2-aminoethyl)} aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- phenyl-3-aminopropyltrimethoxysilane, and the like.
The alkoxysilane compound having a reactive group may be subjected to hydrolysis and condensation reaction simultaneously with the metal alkoxy compound or the silane compound represented by the general formula (1), or the metal alkoxy compound and the silane represented by the general formula (1). After the reaction of the compound is completed, it may be added and reacted.

  Hereinafter, the present invention will be described more specifically with reference to examples. In the following examples,% is based on mass unless otherwise specified.

<Example 1>
In a reaction vessel equipped with a stirrer, a nitrogen introducing tube and a thermometer, 650 g of ethanol as a water-soluble solvent, 650 g of toluene as a nonpolar solvent, 35.55 g (1.98 mol) of water, and 3 g of 85% aqueous phosphoric acid as a catalyst (water) 0.45 g (containing 0.03 mol)) was added and stirred vigorously at room temperature for 10 minutes to obtain a uniformly dissolved mixed solvent. To this mixed solvent, 208 g (1.0 mol) of tetraethoxysilane was added and stirred at 30 ° C. for 1 hour, and then 79.2 g (0.4 mol) of phenyltrimethoxysilane was added. Stir for hours. Next, 54 g (0.45 mol) of dimethyldimethoxysilane was added, and the mixture was reacted at 70 ° C. for 2 hours. Thereafter, the temperature was further raised, ethanol and methanol were removed together with toluene at normal pressure, and silica particles of Example 1 dispersed in toluene were obtained. At this time, the ratio of the molecular weight of the total hydrophobic group to the molecular weight of the metal oxide particle main body is {(77 × 0.4 × 1) + (15 × 0.45 × 2)} / {(60 × 1.0) + (129 × 0.4) + (74 × 0.45)} × 100 = 30.5%. Table 1 shows the ratio of each component.

<Example 2>
The same operation as in Example 1 was conducted except that the amount of phenyltrimethoxysilane was changed from 79.2 g to 198 g (1.0 mol) and the amount of dimethyldimethoxysilane was changed from 54 g to 26.4 g (0.22 mol). And silica particles of Example 2 dispersed in toluene were obtained. Table 1 shows the ratio of each component.

<Example 3>
The silica particles of Example 3 dispersed in toluene were treated in the same manner as in Example 1 except that 62.4 g (0.6 mol) of trimethylmonomethoxysilane was used instead of 54 g of dimethyldimethoxysilane. Obtained. Table 1 shows the ratio of each component.

<Example 4>
Example 1 except that the amount of phenyltrimethoxysilane was changed from 79.2 g to 198 g (1.0 mol), and 34.3 g (0.33 mol) of trimethylmonomethoxysilane was used instead of 54 g of dimethyldimethoxysilane. The silica particles of Example 4 dispersed in toluene were obtained in the same manner as described above. Table 1 shows the ratio of each component.

<Example 5>
The silica particles of Example 5 dispersed in toluene were treated in the same manner as in Example 1 except that 61.2 g (0.45 mol) of methyltrimethoxysilane was used instead of 54 g of dimethyldimethoxysilane. Obtained. Table 1 shows the ratio of each component.

<Example 6>
Example 1 except that the amount of phenyltrimethoxysilane was changed from 79.2 g to 198 g (1.0 mol), and 36.7 g (0.27 mol) of methyltrimethoxysilane was used instead of 54 g of dimethyldimethoxysilane. The silica particles of Example 6 dispersed in toluene were obtained in the same manner as described above. Table 1 shows the ratio of each component.

<Example 7>
The same operation as in Example 1 except that a mixture of 166.4 g (0.8 mol) of tetraethoxysilane and 40.8 g (0.2 mol) of triisopropoxyaluminum was used instead of 208 g of tetraethoxysilane. The silica-alumina composite particles of Example 7 dispersed in toluene were obtained. Table 1 shows the ratio of each component.

<Example 8>
The same operation as in Example 1 except that instead of 208 g of tetraethoxysilane, a mixture of 166.4 g (0.8 mol) of tetraethoxysilane and 56.8 g (0.2 mol) of tetraisopropoxytitanium was used. The silica-titania composite particles of Example 8 dispersed in toluene were obtained. Table 1 shows the ratio of each component.

<Example 9>
To the mixed solvent obtained in the same manner as in Example 1, 208 g (1.0 mol) of tetraethoxysilane was added and stirred at 30 ° C. for 1 hour, and then 39.6 g (0.2 mol) of phenyltrimethoxysilane. And 30 g (0.2 mol) of ethyltrimethoxysilane were added, and the mixture was reacted by stirring at 30 ° C. for 1 hour and at 70 ° C. for 2 hours. Thereafter, the temperature was further raised, ethanol and methanol were removed together with toluene at normal pressure, and silica particles of Example 11 dispersed in toluene were obtained. Table 1 shows the ratio of each component.

<Example 10>
The silica particles of Example 10 dispersed in toluene were treated in the same manner as in Example 1 except that 92.7 g (0.45 mol) of hexyltrimethoxysilane was used instead of 54 g of dimethylmethoxysilane. Obtained. Table 1 shows the ratio of each component.

<Example 11>
The silica particles of Example 11 dispersed in toluene were treated in the same manner as in Example 1 except that 52.4 g (0.2 mol) of decyltrimethoxysilane was used instead of 54 g of dimethylmethoxysilane. Obtained. Table 1 shows the ratio of each component.

<Comparative Example 1>
In a reaction vessel similar to Example 1, 650 g of ethanol, 150 g of toluene, 35.55 g of water and 3 g of 85% phosphoric acid as a catalyst were stirred vigorously for 60 minutes at room temperature, but a part of the water was separated. A uniform mixed solvent was not obtained. When 208 g of tetraethoxysilane was added to this mixed solvent and stirred for 1 hour at 30 ° C., white aggregates were generated. Further, 39.6 g of phenyltrimethoxysilane was added and stirred for 1 hour at 30 ° C., and separation and sedimentation of aggregates occurred, and silica particles dispersed in toluene were not obtained. Table 1 shows the ratio of each component.

<Comparative example 2>
In a reaction vessel similar to that in Example 1, 1300 g of ethanol, 450 g of toluene, 35.55 g of water and 3 g of 85% phosphoric acid as a catalyst were stirred vigorously at room temperature for 10 minutes to obtain a uniformly dissolved mixed solvent. It was. To this mixed solvent, 208 g (1.0 mol) of tetraethoxysilane was added and stirred at 30 ° C. for 1 hour, followed by addition of 39.6 g (0.2 mol) of phenyltrimethoxysilane and 1 hour at 30 ° C. When the mixture was reacted at 70 ° C. for 2 hours, gelation occurred, and silica particles dispersed in toluene could not be obtained. Table 1 shows the ratio of each component.

<Comparative Example 3>
A mixed solvent similar to that in Example 1 was prepared in a reaction vessel similar to that in Example 1, 208 g of tetraethoxysilane was added, and the mixture was stirred at 30 ° C. for 1 hour and then stirred at 70 ° C. for 1 hour. Separation and sedimentation occurred, and silica particles dispersed in toluene were not obtained. Table 1 shows the ratio of each component.

<Comparative example 4>
In a reaction vessel similar to Example 1, 650 g of ethanol, 650 g of toluene, 251.55 g of water and 3 g of 85% phosphoric acid as a catalyst were stirred vigorously for 60 minutes at room temperature, but part of the water was separated, A uniform mixed solvent was not obtained. To this mixed solvent, 208 g of tetraethoxysilane was added and stirred at 30 ° C. for 1 hour, and then 39.6 g of phenyltrimethoxysilane was added and stirred at 30 ° C. for 1 hour. Separation and sedimentation of aggregates occurred. Silica particles dispersed in toluene were not obtained. Table 1 shows the ratio of each component. Table 1 shows the ratio of each component.

TEOS: Tetraethoxysilane PhTMOS: Phenyltrimethoxysilane DMDMOS: Dimethyldimethoxysilane TMMOS: Trimethylmonomethoxysilane MTMOS: Methyltrimethoxysilane ETMOS: Ethyltrimethoxysilane HTMOS: Hexyltrimethoxysilane DTMOS: Decyltrimethoxysilane TPOA: Triiso Propoxy aluminum TPOT: Tetraisopropoxy titanium

About the metal oxide particle of Examples 1-11 and Comparative Examples 1-4, the dispersion state of the metal oxide particle in an organic solvent was evaluated visually. Furthermore, about the metal oxide particle of Examples 1-11, the average particle diameter and solid content were measured. The results are shown in Table 2.
The average particle size was measured by a dynamic light scattering method using MICROTRAC 9340-UPA manufactured by Nikkiso Co., Ltd. The solid content was determined from the residue after precisely weighing 1 g of a sample in a stainless steel petri dish, air-drying at room temperature for 12 hours, and storing in a 110 ° C. constant temperature bath for 3 hours to remove the solvent. The results are shown in Table 2.

(Time stability test method)
100 ml of metal oxide particles dispersed in toluene of Examples 1 to 11 were put in glass bottles and stored in a constant temperature bath at 40 ° C., and the states after 24 hours, 48 hours and 72 hours were visually observed. . The results are shown in Table 3.

As is apparent from Table 2, the metal oxide particles of Examples 1 to 11 obtained according to the present invention were hardly dispersed in a nonpolar solvent and were uniformly dispersed. Furthermore, as is clear from Table 3, the metal oxide particles of Examples 1 to 11 are not precipitated and separated even after 72 hours and are excellent in stability over time. Moreover, the average particle diameter was as fine as 17.5-41.3 nm.
In contrast, the metal oxide particles of Comparative Examples 1 to 4 were aggregated or gelled in a nonpolar organic solvent.

  Since the metal oxide particles of the present invention can be uniformly mixed in the form of primary particles with a functional material that can only be dissolved in a nonpolar solvent, it can be applied to applications such as paint, rubber, printing, catalyst production, and precision surface treatment. it can.

Claims (10)

Different at least two hydrophobic groups, silica via a Si atom, alumina, metal oxide particles are chemically bonded to the surface of the titania or the metal oxide particles body consisting of composite, tetra A metal alkoxy compound comprising alkoxysilane, trialkoxyaluminum, tetraalkoxytitanium or a mixture of two or more thereof, and the following general formula (1)
R _n SiX _4-n (1)
(Wherein R represents a hydrophobic group, X represents an alkoxyl group having 1 to 4 carbon atoms or a chlorine atom, and n represents a number of 1 to 3). A silane compound is added to a mixed solvent containing a water-soluble organic solvent, a nonpolar organic solvent and water, and is subjected to hydrolysis and condensation reaction. The ratio of the molecular weight of the total hydrophobic group to the molecular weight of the metal oxide particle body is Metal oxide particles characterized by being 20% to 60% and having an average particle diameter of 1 to 100 nm.   2. The metal oxide particle according to claim 1, wherein one of the hydrophobic groups is an aliphatic hydrocarbon group, and the other is an aromatic hydrocarbon group.   The metal oxide particle according to claim 2, wherein the aliphatic hydrocarbon group is an aliphatic saturated hydrocarbon group.   4. The metal oxide particle according to claim 3, wherein the aliphatic saturated hydrocarbon group is an alkyl group having an unsubstituted or non-reactive substituent.   4. The metal oxide particle according to claim 3, wherein the aliphatic saturated hydrocarbon group is a linear or branched alkyl group having 1 to 8 carbon atoms.   The metal oxide particle according to any one of claims 2 to 5, wherein the aromatic hydrocarbon group is an aryl group having an unsubstituted or non-reactive substituent.   The metal oxide particle according to claim 6, wherein the aryl group is a phenyl group. This is a method for producing metal oxide particles in which at least two different types of hydrophobic groups are chemically bonded to the surface of a metal oxide particle body composed of silica, alumina, titania or a composite thereof via Si atoms. And
A metal alkoxy compound comprising tetraalkoxysilane, trialkoxyaluminum, tetraalkoxytitanium or a mixture of two or more thereof, and the following general formula (1)
R _n SiX _4-n       (1)
(Wherein R represents a hydrophobic group, X represents an alkoxyl group having 1 to 4 carbon atoms or a chlorine atom, and n represents a number of 1 to 3). A method for producing metal oxide particles, comprising adding a silane compound to a mixed solvent containing a water-soluble organic solvent, a nonpolar organic solvent, and water, followed by hydrolysis and condensation reaction. The amount ratio between the metal alkoxy compound and the at least two silane compounds having different hydrophobic groups is such that the ratio of the molecular weight of the total hydrophobic groups to the molecular weight of the metal oxide particle body is 20% to 60%. The method for producing metal oxide particles according to claim 8, 10. The mixed solvent according to claim 8, wherein a solvent containing 50 to 300 parts by mass of a nonpolar organic solvent and 0.1 to 35 parts by mass of water is used with respect to 100 parts by mass of the water-soluble organic solvent. The manufacturing method of the metal oxide particle of description.