JP2009256131A - Inorganic oxide particle, inorganic oxide particle dispersion, and production method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method of a new inorganic oxide particle dispersion. <P>SOLUTION: The production method of an inorganic oxide particle dispersion comprises stirring particles made of an inorganic oxide and a solution containing a surface modifier in a wet medium mill. The inorganic oxide is preferably an oxide of one element selected from Si, Ti, W, V, Y, Ag, Mg, Al, Fe, Ni, Ce, Co, Mo, Au, Pt, Ta, Lu, Zr, Cu, Zn, Pd, Cd, Cr, Pb and Mn or oxides of a combination of two or more elements. The surface modifier is preferably a coupling agent or a surfactant. When water is added, the ratio of the mole number of water to the mole number of alkoxy groups included in the coupling agent is preferably in a range from 0.1 to 5. The wet medium mill is preferably a bead mill. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to novel inorganic oxide particles. The present invention also relates to a novel inorganic oxide particle dispersion. The present invention also relates to a novel method for producing inorganic oxide particles. The present invention also relates to a method for producing a novel inorganic oxide particle dispersion.

  Nanoparticles are produced by various methods such as a method of synthesizing in a liquid phase, a method of pulverizing a solid, and a method of synthesizing from a gas phase. When these nanoparticles are used in a dispersed state, the performance of the product is improved. Therefore, various dispersion methods are being studied.

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For example, a method has been reported in which fine particles are surface-modified with a bead mill to produce a fine particle dispersion (see Patent Document 1).

  In addition, after surface modification of fine particles with a bead mill, it is reported that the solution is heated to dry the particles, and the obtained particles are put into the bead mill again and pulverized to obtain a uniformly dispersed slurry (patent) Reference 2).

  In addition, a method of dispersing fine particles (primary particle size of 15 nm) in water to a size of one particle in a bead mill has been reported (see Non-Patent Document 1).

  On the other hand, it has been reported that a coupling agent reacts with aggregated particles (see Non-Patent Document 2).

  The inventor has disclosed the technical contents related to the present invention (see Non-Patent Document 3). This is considered to be applicable to Patent Act Article 30 (1).

JP2007-308631 JP2005-113110 M. Inkyo et al., J. Colloid. Interface Sci. 304 (2006) 535 M. Iijima et al., J. Colloid. Interface Sci. 305 (2007) 315 Noriyuki Furukawa et al. “Dispersion of Silica Nanoparticles by Combination of Coupling Process and Physical Method” Autumn Meeting of Powder Engineering Society (October 17, 18th, 2007)

  As described above, the surface of fine particles is modified by a bead mill to produce a fine particle dispersion (see Patent Document 1). However, the stability of the dispersion solution has not been studied at all.

  In addition, after surface modification of fine particles with a bead mill, it is reported that the solution is heated to dry the particles, and the obtained particles are put into the bead mill again and pulverized to obtain a uniformly dispersed slurry (patent) Reference 2). However, this method requires two stages of processing in order to obtain a uniformly dispersed slurry. Furthermore, no investigation has been made on the stability of the resulting dispersion.

  In addition, a method of dispersing fine particles (primary particle size of 15 nm) in water to a size of one particle in a bead mill has been reported (see Non-Patent Document 1). However, since the particles are not surface-modified, there is a problem in dispersion stability because the particles tend to aggregate again after being dispersed to the size of one particle.

  On the other hand, it has been reported that a coupling agent reacts with aggregated particles (see Non-Patent Document 2). However, there is no description of the contents relating to the production of the dispersion solution refined to primary particles.

Therefore, development of novel inorganic oxide particles and novel inorganic oxide particle dispersions that solve such problems is desired.
In addition, development of a novel method for producing inorganic oxide particles and a novel method for producing inorganic oxide particle dispersions are desired.

  This invention is made | formed in view of such a subject, and it aims at providing a novel inorganic oxide particle. Another object of the present invention is to provide a novel inorganic oxide particle dispersion.

  Another object of the present invention is to provide a novel method for producing inorganic oxide particles. Moreover, an object of this invention is to provide the manufacturing method of a novel inorganic oxide particle dispersion.

  In order to solve the above-mentioned problems and achieve the object of the present invention, the inorganic oxide particles of the present invention have a surface modifier on the surface of the particles made of the inorganic oxide, and the 50% particle size is in the range of 8.9 to 545 nm. Is in.

Here, although not limited, inorganic oxides include Si, Ti, W, V, Y, Ag, Mg, Al, Fe, Ni, Ce, Co, Mo, Au, Pt, Ta, Lu, It is preferably any one oxide selected from Zr, Cu, Zn, Pd, Cd, Cr, Pb, and Mn, or an oxide of any combination of two or more. Moreover, although not necessarily limited, it is preferable that a surface modifier is a coupling agent or surfactant. Moreover, although not necessarily limited, it is preferable that a coupling agent is a compound represented by the following general formula. SiR _x (OR ′) _{4-x In} this general formula, R 1 represents a vinyl group; an allyl group; a 3-glycidoxypropyl group; a 2- (3,4-epoxycyclohexyl) ethyl group; a 3-acryloxypropyl group; 3-methacrylopropyl group; styryl group; 3-aminopropyl group; N-2 (aminoethyl) 3-aminopropyl group; N-phenyl-3-aminopropyl group; alkyl group having 1 to 20 carbon atoms One or more selected from a phenyl group. In this general formula, R ′ is an alkyl group having 1 to 20 carbon atoms; one or more selected from a phenyl group and a methylcarboxy group. Although not limited, the surfactant is any one selected from anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc., or any two A combination of at least species is preferred. Further, although not limited, it is preferable that the 80% particle size is in the range of 16 to 982 nm. Moreover, although not necessarily limited, it is preferable that the amount of the surface modifier reacted per particle unit surface area is in the range of 3.0 to 8.0 μmol / m ² .

  The inorganic oxide particle dispersion of the present invention contains inorganic oxide particles in which a surface modifier is present on the surface of particles made of an inorganic oxide and the 50% particle size is in the range of 8.9 to 545 nm. .

Here, although not limited, inorganic oxides include Si, Ti, W, V, Y, Ag, Mg, Al, Fe, Ni, Ce, Co, Mo, Au, Pt, Ta, Lu, It is preferably any one oxide selected from Zr, Cu, Zn, Pd, Cd, Cr, Pb, and Mn, or an oxide of any combination of two or more. Moreover, although not necessarily limited, it is preferable that a surface modifier is a coupling agent or surfactant. Moreover, although not necessarily limited, it is preferable that a coupling agent is a compound represented by the following general formula. SiR _x (OR ′) _{4-x In} this general formula, R 1 represents a vinyl group; an allyl group; a 3-glycidoxypropyl group; a 2- (3,4-epoxycyclohexyl) ethyl group; a 3-acryloxypropyl group; 3-methacrylopropyl group; styryl group; 3-aminopropyl group; N-2 (aminoethyl) 3-aminopropyl group; N-phenyl-3-aminopropyl group; alkyl group having 1 to 20 carbon atoms One or more selected from a phenyl group. In this general formula, R ′ is an alkyl group having 1 to 20 carbon atoms; one or more selected from a phenyl group and a methylcarboxy group. Although not limited, the surfactant is any one selected from anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc., or any two A combination of more than one species is preferable. Further, although not limited, it is preferable that the 80% particle size is in the range of 16 to 982 nm. Moreover, although not necessarily limited, it is preferable that the amount of the surface modifier reacted per particle unit surface area is in the range of 3.0 to 8.0 μmol / m ² .

  The method for producing inorganic oxide particles according to the present invention is a method in which particles comprising an inorganic oxide and a solution containing a surface modifier are stirred by a wet medium mill.

Here, although not limited, inorganic oxides include Si, Ti, W, V, Y, Ag, Mg, Al, Fe, Ni, Ce, Co, Mo, Au, Pt, Ta, Lu, It is preferably any one oxide selected from Zr, Cu, Zn, Pd, Cd, Cr, Pb, and Mn, or an oxide of any combination of two or more. Moreover, although not necessarily limited, it is preferable that a surface modifier is a coupling agent or surfactant. Moreover, although not necessarily limited, it is preferable that a coupling agent is a compound represented by the following general formula. SiR _x (OR ′) _{4-x In} this general formula, R 1 represents a vinyl group; an allyl group; a 3-glycidoxypropyl group; a 2- (3,4-epoxycyclohexyl) ethyl group; a 3-acryloxypropyl group; 3-methacrylopropyl group; styryl group; 3-aminopropyl group; N-2 (aminoethyl) 3-aminopropyl group; N-phenyl-3-aminopropyl group; alkyl group having 1 to 20 carbon atoms One or more selected from a phenyl group. In this general formula, R ′ is an alkyl group having 1 to 20 carbon atoms; one or more selected from a phenyl group and a methylcarboxy group. Although not limited, the surfactant is any one selected from anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc., or any two A combination of more than one species is preferable. Although not limited, in the addition of water, the ratio of the number of moles of water to the number of moles of alkoxy groups contained in the coupling agent is preferably in the range of 0.1 to 5. Although not limited, the wet medium mill is preferably a bead mill.

  The method for producing an inorganic oxide particle dispersion according to the present invention is a method in which particles comprising an inorganic oxide and a solution containing a surface modifier are stirred by a wet medium mill.

Here, although not limited, inorganic oxides include Si, Ti, W, V, Y, Ag, Mg, Al, Fe, Ni, Ce, Co, Mo, Au, Pt, Ta, Lu, It is preferably any one oxide selected from Zr, Cu, Zn, Pd, Cd, Cr, Pb, and Mn, or an oxide of any combination of two or more. Moreover, although not necessarily limited, it is preferable that a surface modifier is a coupling agent or surfactant. Moreover, although not necessarily limited, it is preferable that a coupling agent is a compound represented by the following general formula. SiR _x (OR ′) _{4-x In} this general formula, R 1 represents a vinyl group; an allyl group; a 3-glycidoxypropyl group; a 2- (3,4-epoxycyclohexyl) ethyl group; a 3-acryloxypropyl group; 3-methacrylopropyl group; styryl group; 3-aminopropyl group; N-2 (aminoethyl) 3-aminopropyl group; N-phenyl-3-aminopropyl group; alkyl group having 1 to 20 carbon atoms One or more selected from a phenyl group. In this general formula, R ′ is an alkyl group having 1 to 20 carbon atoms; one or more selected from a phenyl group and a methylcarboxy group. Although not limited, the surfactant is any one selected from anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc., or any two A combination of at least species is preferred. Although not limited, in the addition of water, the ratio of the number of moles of water to the number of moles of alkoxy groups contained in the coupling agent is preferably in the range of 0.1 to 5. Although not limited, the wet medium mill is preferably a bead mill.

  The present invention has the following effects.

  The inorganic oxide particles of the present invention provide a novel inorganic oxide particle because the surface modifier is present on the surface of the particle made of the inorganic oxide and the 50% particle size is in the range of 8.9 to 545 nm. Can do.

  The inorganic oxide particle dispersion of the present invention has a surface modifier on the surface of particles made of an inorganic oxide and contains inorganic oxide particles having a 50% particle size in the range of 8.9 to 545 nm. An inorganic oxide particle dispersion can be provided.

  In the method for producing inorganic oxide particles according to the present invention, the particles comprising the inorganic oxide and the solution containing the surface modifier are stirred by a wet medium mill, so that a novel method for producing inorganic oxide particles can be provided. .

  The method for producing an inorganic oxide particle dispersion according to the present invention provides a novel method for producing an inorganic oxide particle dispersion because a solution containing an inorganic oxide and a solution containing a surface modifier are stirred by a wet medium mill. can do.

Hereinafter, the best mode for carrying out the present invention will be described.
First, the best mode for carrying out the invention relating to the method for producing inorganic oxide particles and the method for producing inorganic oxide particle dispersion will be described.

The method for producing inorganic oxide particles is a method in which a particle containing an inorganic oxide and a solution containing a surface modifier are stirred by a wet medium mill.
The manufacturing method of an inorganic oxide particle dispersion is a method in which particles comprising an inorganic oxide and a solution containing a surface modifier are stirred by a wet medium mill.

  Inorganic oxides include Si, Ti, W, V, Y, Ag, Mg, Al, Fe, Ni, Ce, Co, Mo, Au, Pt, Ta, Lu, Zr, Cu, Zn, Pd, Cd, Any one oxide selected from Cr, Pb, Mn, etc., or any combination of two or more oxides can be employed.

As the surface modifier, a coupling agent or a surfactant can be employed.
As the coupling agent, a silane coupling agent, a titanium coupling agent, or the like can be employed.

The silane coupling agent is a compound represented by the following general formula.
SiR _x (OR ') _4-x
In this general formula, R 1 represents a vinyl group; an allyl group; a 3-glycidoxypropyl group; a 2- (3,4-epoxycyclohexyl) ethyl group; a 3-acryloxypropyl group; a 3-methacrylopropyl group; 3-aminopropyl group; N-2 (aminoethyl) 3-aminopropyl group; N-phenyl-3-aminopropyl group; alkyl group having 1 to 20 carbon atoms; one kind selected from phenyl group; Or it is 2 or more types.
In this general formula, R ′ is an alkyl group having 1 to 20 carbon atoms; one or more selected from a phenyl group and a methylcarboxy group.

  As the surfactant, any one selected from anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc., or a combination of any two or more thereof may be employed. it can.

  When a coupling agent is used, addition of water is preferable. In the addition of water, the ratio of the number of moles of water to the number of moles of alkoxy groups contained in the coupling agent is preferably in the range of 0.1 to 5. The ratio of the number of moles of water to the number of moles of alkoxy groups is more preferably in the range of 0.5-3.

  When the ratio of the number of moles of water to the number of moles of alkoxy groups is 0.1 or more, there is an advantage that the reaction amount of the coupling agent increases. This effect becomes more remarkable when the ratio of the number of moles of water to the number of moles of alkoxy groups is 0.5 or more.

  When the ratio of the number of moles of water to the number of moles of alkoxy groups is 5 or less, there is an advantage that the reaction amount of the coupling agent increases. This effect becomes more prominent when the ratio of the number of moles of water to the number of moles of alkoxy groups is 3 or less.

  Solvents include alcohols such as methanol, ethanol, 2-propanol, butanol and octanol, esters such as ethyl acetate, butyl acetate, ethyl lactate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, γ-butyrolactone, Diethyl ether, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), ethylene glycol monobutyl ether (butyl cellosolve), ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, acetone, methyl ethyl ketone, methyl isobutyl ketone , Ketones such as acetylacetone and cyclohexanone, benze Aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene, dimethylformamide, N 2, N-dimethylacetoacetamide, N 2 -methylpyrrolidone, water), etc., or a combination of two or more Can be adopted.

  The solution temperature in the stirring in the wet medium mill is preferably in the range of 10 to 120 ° C. The solution temperature is more preferably in the range of 27 to 70 ° C.

  When the solution temperature is 10 ° C. or more and 120 ° C. or less, there is an advantage that the solvent is difficult to volatilize. This effect becomes more remarkable when the solution temperature is 27 ° C. or higher and 70 ° C. or lower.

  It is preferable that the pH of the water to be added in the stirring in the wet medium mill is in the range of 1 to 14. The pH of the water to be added is more preferably in the range of 3-12.

  When the pH of the water to be added is 1 or more, there is an advantage that the reaction amount of the coupling agent is improved. This effect becomes more remarkable when the pH of the water to be added is 3 or more. When the pH of the water to be added is 14 or less, there is an advantage that the reaction amount of the coupling agent is improved. This effect becomes more remarkable when the pH of the solution is 12 or less.

As the wet medium mill, a bead mill or a ball mill can be employed.
The particle size of the medium particles used in the wet medium mill is preferably in the range of 15 to 2500 μm. When the medium particle diameter is 15 μm or more, there is an advantage that the dispersion solution and the beads can be easily separated. When the particle size is 2500 μm or less, there is an advantage that a dispersion solution of fine particles can be prepared.

  The present invention is not limited to the best mode for carrying out the above-described invention, and various other configurations can be adopted without departing from the gist of the present invention.

  Next, the best mode for carrying out the invention relating to the inorganic oxide particles and the inorganic oxide particle dispersion will be described.

The inorganic oxide particles have a surface modifier on the surface of particles made of an inorganic oxide and have a 50% particle size in the range of 8.9 to 545 nm.
The inorganic oxide particle dispersion contains inorganic oxide particles having a surface modifier on the surface of particles made of an inorganic oxide and having a 50% particle size in the range of 8.9 to 545 nm.

  As the inorganic oxide, those described above can be employed.

  The 50% particle size of the inorganic oxide particles is preferably in the range of 8.9 to 545 nm. The 50% particle size is more preferably in the range of 8.9 to 15.5 nm.

  When the 50% particle size is 8.9 nm or more, there is an advantage that the long-term stability of the dispersion solution is improved. When the 50% particle size is 545 nm or less, there is an advantage that the long-term stability of the dispersion solution is improved. This effect becomes more prominent when the 50% particle size is 15.5 nm or less.

  The 80% particle size of the inorganic oxide particles is preferably in the range of 16 to 982 nm. The 80% particle size is more preferably in the range of 16 to 100 nm.

  When the 80% particle size is 16 nm or more, there is an advantage that the long-term stability of the dispersion solution is improved. When the 80% particle size is 982 nm or less, there is an advantage that the long-term stability of the dispersion is improved. When the 80% particle size is 100 nm or less, this effect becomes more remarkable.

  As the surface modifier, those described above can be employed. The surface modifier is physically adsorbed or chemically bonded to the surface of the inorganic oxide.

The amount of the coupling agent reacted per particle unit surface area is preferably in the range of 3.0 to 8.0 μmol / m ² . Further, the amount of the coupling agent reacted per particle unit surface area is more preferably in the range of 5.2 to 6.2 μmol / m ² .

When the amount of the coupling agent reacted per particle unit surface area is 3.0 μmol / m ² or more, there is an advantage that the stability of the dispersion solution is improved. This effect becomes more remarkable when the amount of the coupling agent reacted per particle unit surface area is 5.2 μmol / m ² or more.

When the amount of the coupling agent reacted per particle unit surface area is 8.0 μmol / m ² or less, there is an advantage that the stability of the dispersion solution is improved. This effect becomes more remarkable when the amount of the coupling agent reacted per particle unit surface area is 6.2 μmol / m ² or less.

  The present invention is not limited to the best mode for carrying out the above-described invention, and various other configurations can be adopted without departing from the gist of the present invention.

  Next, specific examples of the present invention will be described. However, it goes without saying that the present invention is not limited to these examples.

  The preparation of the sample will be described.

Example 1
First, N-methyl-2-pyrrolidone (99%, Kanto Chemical Co., Inc.) as an organic solvent in a beaker, N-Phenyl-3-aminopropyltrimethoxysilane (Momentive performance materials Inc.), a cup as a coupling agent as a surface modifier Water was added as a reaction accelerator for the ring agent. Here, the pH of the water is adjusted to 12 using sodium hydroxide. 1% by mass of this water was added with respect to the mass of the solvent (the addition amount of this water is an equimolar amount of the alkoxy group of the coupling agent). N-Phenyl-3-aminopropyltrimethoxysilane was added in an amount of 4.7% by mass relative to the mass of the solvent. The mixed solution of the organic solvent, the coupling agent, and water was stirred with a magnetic stirrer for 30 seconds. To the stirred solution, 5% by mass of SiO ₂ particles (BET conversion diameter: 10.5 nm, Hosokawa Powder Technology Laboratory) based on the organic solvent was added, and the solution containing these particles was stirred with a magnetic stirrer for 5 minutes.

A bead mill (PCM-LR, Asada Tekko Co., Ltd.) container was filled with 207.4 g of ZrO ₂ beads (grade φ30, Kobun Kogyo Co., Ltd.) having an average particle size of 30 μm. A bead mill container and the above solution were placed in the apparatus main body. The container of the bead mill has a double structure, and tap water was allowed to flow through it to cool the internal dispersion solution. The bead mill rotor peripheral speed was set to 10 m / s and stirring was started. The mill was stopped after 1 hour of stirring. After stopping, the temperature of the solution was measured and found to be 30 ° C. The solution thus obtained was used as a sample.

Example 2
The same as Example 1 except that the stirring time in the bead mill was 3 h.

Example 3
The same as Example 1 except that the stirring time in the bead mill was set to 5 hours.

Example 4
The same as Example 1 except that the stirring time in the bead mill was 8 h.

Comparative Example 1
A sample obtained by stirring a mixed solution of an organic solvent, a coupling agent, water and particles in Example 1 with a magnetic stirrer for 5 minutes was used as a sample.

Comparative Example 2
N-methyl-2-pyrrolidone (99%, Kanto Chemical Co., Inc.) as an organic solvent in a beaker, N-Phenyl-3-aminopropyltrimethoxysilane (Momentive performance materials Inc.) as a coupling agent as a surface modifier, Water was added as a reaction accelerator. Here, the pH of the water is adjusted to 12 using sodium hydroxide. 1% by mass of this water was added with respect to the solvent mass. N-Phenyl-3-aminopropyltrimethoxysilane was added in an amount of 4.7% by mass relative to the mass of the solvent. A sample obtained by stirring this mixed solution with a magnetic stirrer for 1 hour was used.

Comparative Example 3
It is the same as that of the comparative example 2 except having stirred for 3 hours with the magnetic stirrer.

Comparative Example 4
It is the same as that of the comparative example 2 except having stirred for 8 hours with the magnetic stirrer.

Example 5
Example 1 is the same as Example 1 except that the pH of the water was adjusted to 3 with an aqueous hydrogen chloride solution and this water was used, and the mixture was stirred for 30 hours after being stirred for 8 hours. This solution was used as a sample.

Example 6
Example 1 is the same as Example 1 except that the pH of the water was adjusted to 7 with an aqueous hydrogen chloride solution or sodium hydroxide and this water was used, and the mixture was stirred for 8 hours for 30 hours and then left for 30 days. This solution was used as a sample.

Example 7
Example 1 is the same as Example 1 except that stirring for 8 hours was performed for 30 days after bead milling. This solution was used as a sample.

Example 8
Example 1 is the same as Example 1 except that the pH of the water was adjusted to 3 with an aqueous hydrogen chloride solution and this water was used, and the mixture was stirred for 8 hours and then left for 180 days. This solution was used as a sample.

Example 9
Example 1 is the same as Example 1 except that the pH of the water was adjusted to 7 with an aqueous hydrogen chloride solution or sodium hydroxide and this water was used, and after stirring for 8 hours in the bead mill, it was left for 180 days. This solution was used as a sample.

Example 10
Example 1 is the same as Example 1 except that stirring is performed in a bead mill for 8 hours and then 180 days. This solution was used as a sample.

Comparative Example 5
Example 1 is the same as Example 1 except that no coupling agent is used and the bead mill stirring time is set to 1 h, 3 h, and 4 h. This solution was used as a sample.

Comparative Example 6
N-methyl-2-pyrrolidone (99%, Kanto Chemical Co., Inc.) as an organic solvent in a beaker, N-Phenyl-3-aminopropyltrimethoxysilane (Momentive performance materials Inc.) as a coupling agent as a surface modifier, Water was added as a reaction accelerator. Here, the pH of the water is adjusted to 12 using sodium hydroxide. 1% by mass of this water was added with respect to the solvent mass. N-Phenyl-3-aminopropyltrimethoxysilane was added in an amount of 4.7% by mass relative to the mass of the solvent. The mixed solution of the organic solvent, the coupling agent, and water was stirred with a magnetic stirrer for 30 seconds. To the stirred solution, 5% by mass of SiO ₂ particles (BET conversion diameter: 10.5 nm, Hosokawa Powder Technology Laboratory) based on the organic solvent was added, and the solution containing these particles was stirred with a magnetic stirrer for 5 minutes. This solution was used as a sample.

Comparative Example 7
It is the same as that of the comparative example 6 except having stirred for 1 h with the magnetic stirrer. This solution was used as a sample.

Comparative Example 8
It is the same as that of the comparative example 6 except having stirred for 3 hours with the magnetic stirrer. This solution was used as a sample.

Comparative Example 9
It is the same as that of the comparative example 6 except having stirred for 8 hours with the magnetic stirrer. This solution was used as a sample.

Comparative Example 10
N-methyl-2-pyrrolidone (99%, Kanto Chemical Co., Inc.) as an organic solvent in a beaker, N-Phenyl-3-aminopropyltrimethoxysilane (Momentive performance materials Inc.) as a coupling agent as a surface modifier, Water was added as a reaction accelerator. Here, the pH of the water is adjusted to 12 using sodium hydroxide. 1% by mass of this water was added with respect to the solvent mass. N-Phenyl-3-aminopropyltrimethoxysilane was added in an amount of 4.7% by mass relative to the mass of the solvent. The mixed solution of the organic solvent, the coupling agent, and water was stirred with a magnetic stirrer for 30 seconds. To the stirred solution, 5% by mass of SiO ₂ particles (BET converted diameter: 10.5 nm, Hosokawa Powder Technology Laboratory) based on the organic solvent was added, and the solution containing these particles was stirred with a magnetic stirrer for 8 hours. The temperature during stirring is 27 ° C. This solution was used as a sample.

Comparative Example 11
The same as Comparative Example 10, except that the pH of water was adjusted to 3 with an aqueous hydrogen chloride solution and this water was used.

Comparative Example 12
The same as Comparative Example 10 except that the pH of water was adjusted to 7 with an aqueous hydrogen chloride solution or sodium hydroxide and this water was used.

Comparative Example 13
The same as Comparative Example 10, except that the temperature during stirring was 47 ° C.

Comparative Example 14
Comparative Example 10 is the same as Comparative Example 10 except that the pH of the water was adjusted to 3 with an aqueous hydrogen chloride solution and this water was used, and that the temperature during stirring was 47 ° C.

Comparative Example 15
The same as Comparative Example 10, except that the pH of the water was adjusted to 7 with an aqueous hydrogen chloride solution or sodium hydroxide and this water was used, and that the temperature during stirring was 47 ° C.

Comparative Example 16
The same as Comparative Example 10, except that the temperature during stirring was set to 70 ° C.

Comparative Example 17
Comparative Example 10 is the same as Comparative Example 10 except that the pH of water was adjusted to 3 with an aqueous hydrogen chloride solution and this water was used, and that the temperature during stirring was 70 ° C.

Comparative Example 18
Comparative Example 10 is the same as Comparative Example 10 except that the pH of water was adjusted to 7 with an aqueous hydrogen chloride solution or sodium hydroxide and this water was used, and that the temperature during stirring was 70 ° C.

Example 11
N-methyl-2-pyrrolidone (99%, Kanto Chemical Co., Inc.) as an organic solvent in a beaker, N-Phenyl-3-aminopropyltrimethoxysilane (Momentive performance materials Inc.) as a coupling agent as a surface modifier, Water was added as a reaction accelerator. Here, the pH of the water is adjusted to 12 using sodium hydroxide. This water was added at 0.37% by mass with respect to the solvent mass. N-Phenyl-3-aminopropyltrimethoxysilane was added in an amount of 1.7% by mass relative to the mass of the solvent. The mixed solution of the organic solvent, the coupling agent, and water was stirred with a magnetic stirrer for 30 seconds. A solution containing 5% by mass of 80% by mass SiO ₂ /20% by mass TiO ₂ particles (BET equivalent diameter: 22 nm, Hosokawa Powder Technology Laboratory) based on the organic solvent is added to the stirred solution. Was stirred for 5 minutes with a magnetic stirrer.

A bead mill (PCM-LR, Asada Tekko Co., Ltd.) container was filled with 207.4 g of ZrO ₂ beads (grade φ30, Kobun Kogyo Co., Ltd.) having an average particle size of 30 μm. A bead mill container and the above solution were placed in the apparatus main body. The container of the bead mill has a double structure, and tap water was allowed to flow through it to cool the internal dispersion solution. The pressure is atmospheric pressure. The bead mill rotor peripheral speed was set to 10 m / s and stirring was started. The mill was stopped after 1 hour of stirring. The solution thus obtained was used as a sample.

Example 12
The same as Example 11 except that the stirring time in the bead mill was 4 h.

Example 13
Example 11 is the same as Example 11 except that the stirring time in the bead mill is 6 hours.

Example 14
Example 11 is the same as Example 11 except that the stirring time in the bead mill is 8 hours.

Comparative Example 19
In Example 11, a sample obtained by stirring a mixed solution of an organic solvent, a coupling agent, water, and particles with a magnetic stirrer for 5 minutes was used as a sample.

Example 15
Example 11 is the same as Example 11 except that the pH of the water was adjusted to 3 with an aqueous hydrogen chloride solution and this water was used, and that the stirring time was 8 hours.

  An evaluation method and an evaluation result will be described.

In order to confirm whether the adjusted sample (used particles: SiO ₂ ) was a solution dispersed as fine particles, the particle size distribution was measured by a dynamic light scattering particle size distribution analyzer (HP5001, Malvern Instruments Ltd). The vertical axis in FIG. 1 is the volume-based integration ratio, and the horizontal axis is the particle diameter. In addition, there is a vertical dotted line in FIG. 1 and there is a description that the primary particle diameter is 10.5 nm. This is a particle calculated from the value obtained by BET measurement (specific surface area measurement) in the state of the powder of the particle used. Is the diameter. In the case of microparticles, this particle size is almost the same as the particle size observed with an electron microscope. As shown in Examples 1 to 4 and Comparative Example 1, the stirring time in the bead mill was set to 0h, 1h, 3h, 5h, and 8h. It was confirmed that the particle diameter decreased as the stirring time increased. Especially after 8 hours of stirring, since the size is on the order of nanometers, it is possible to produce a solution in which almost all the fine particles that have been intensively aggregated from the initial powder state are dispersed to the size of one particle. did it.

  FIG. 2 shows the 50% and 80% particle diameters from FIG. 1, and FIG. In addition, the value of 100 nm in the notes in Table 1 was obtained by interpolation from the values of 300 min and 480 min. Both 50% and 80% particle sizes were found to decrease significantly over time. In particular, after stirring for 8 hours, the 50% and 80% particle sizes were 8.9 nm and 15.4 nm, respectively, indicating that a dispersion having a very sharp particle size distribution can be produced.

  In FIG. 1, the produced dispersion contains a particle containing about 10% larger particles. In order to confirm whether this is due to particles or whether the coupling agent grows large by bonding and is measured as particles, the particle size distribution when stirring with a stirrer without particles is adjusted. Measured with an automatic light scattering particle size distribution analyzer. In this figure, the vertical axis represents the volume-based integration ratio, and the horizontal axis represents the particle diameter. As shown in Comparative Examples 2 to 4, it was found that the particle size distribution had a size in the range of 300 nm to 700 nm at any time at the stirring times of 1 h, 3 h, and 8 h. From this result, it was found that the coupling agent was bonded to each other in the initial stage of stirring to form particles, and this was detected by dynamic light scattering particle size distribution measurement.

  The result of FIG. 1 was examined again based on the result of FIG. Those containing about 10% had a particle size in the range of 250 to 800 nm, which was found to coincide with the particle size measured in FIG. That is, about 10% of this is due to the coupling agent. From this result, the particle size distribution in FIG. 1 represents the result including the coupling agent. When viewed as the particle size distribution of the particles themselves, almost 80% or more of the particles are dispersed as one particle. I can guess. Based on the results of FIGS. 1 to 3, a solution in which the particle size distribution is very sharp and the particles are dispersed in one size can be produced according to the present invention.

  In order to confirm whether the pH of the water added in the preparation of the sample affects the dispersibility and whether the dispersion state of the obtained solution is stable, the water added as shown in Examples 5 to 7 The pH was set to 3, 7, 12, and a sample which was stirred for 8 hours with a bead mill and kept for 30 days was used. The particle size distribution of this sample was measured with a dynamic light scattering particle size distribution analyzer. In this figure, the vertical axis represents the volume-based integration ratio, and the horizontal axis represents the particle diameter. It was found that the same particle size distribution could be obtained even when the pH of the added water was changed. Moreover, when the result of stirring for 8 hours in FIG. 1 was compared, it was found that the particle size distribution of this sample was not changed. From this result, it was found that the dispersion solution was stable for 30 days.

  Although it was confirmed that there was stability for 30 days in FIG. 5, in order to confirm whether there was stability for a longer period of time, as shown in Examples 8 to 10, the particle size distribution of the sample after 180 days was measured. It was measured with a dynamic light scattering particle size distribution measuring device. Although some coarsening of the particles was confirmed in comparison with the sample kept for 30 days, it was found that about 70% of the particles were dispersed as one particle size. Moreover, it has confirmed that it was not influenced by the pH of the water to add from this result. From the above results, it was found that a very stable dispersion solution can be produced by the present invention.

  In the present invention, in order to confirm whether a highly stable dispersion solution can be produced for the first time by using a coupling agent and a bead mill, first, as shown in Comparative Example 5, coupling is performed. Agitation was performed when no agent was used. The particle size distribution of the sample thus obtained is measured by a dynamic light scattering particle size distribution measuring apparatus, and the 50% and 90% particle diameter changes with time are shown from the measurement results. It was found that when no coupling agent was used in the agitation with the bead mill, the particle diameter decreased until a certain time as in the case where the coupling agent was added, but thereafter the particle diameter increased again.

  Moreover, in order to confirm whether the dispersion solution obtained by this invention was obtained even if it was not a bead mill, it stirred with the stirrer as shown in Comparative Examples 6-9. The particle size distribution of the sample thus obtained is measured by a dynamic light scattering particle size distribution measuring apparatus, and the 50% and 90% particle diameter changes with time are shown from the measurement results. It was found that stirring with a stirrer did not reduce the particles at all. Based on FIGS. 7 and 8, it was confirmed that the particle diameter could be reduced for the first time by the present invention.

The reaction amount of the coupling agent to the particles in the dispersion obtained by the present invention was confirmed using an elemental analyzer (JM10 MICRO CODER, J-SCIENCE LAB Co., Ltd). Here, as a sample for elemental analysis, particles obtained by drying the solvent of the dispersion solution were used. The vertical axis in the figure indicates the amount of reaction of the coupling agent per unit surface area of the input particles. As compared with what was stirred with the bead mill, what was stirred with the stirrer was performed as shown in Comparative Examples 10-11. The amount of reaction of the coupling agent was 5.6, 5.2, 6,2 [μmol / m ² ] at pH 3, 7, 12, respectively, when stirring was performed with a bead mill. There was no difference in the pH of water added to both the bead mill and the stirrer. This result is consistent with the results of FIGS. In addition, it was confirmed that about 3 times as much coupling agent reacted with the one stirred with the bead mill as compared with the one stirred with the stirrer. It is considered that a stable dispersion solution was obtained due to the difference in the reaction amount. The increase in the coupling agent reaction amount is due to the effect of facilitating the reaction between the OH group and the OH group on the particle surface in order to promote the change of the alkoxy group of the coupling agent to the OH group by the addition of water.

  In FIG. 9, it was found that there was a difference in the reaction amount of the coupling agent depending on the stirring method. In the bead mill, friction is caused by beads, and it is considered that the reaction is accelerated and the reaction amount is increased due to this frictional heat. Therefore, the influence of the temperature on the coupling agent reaction amount is confirmed as shown in Comparative Examples 13-18. did. The vertical axis represents the reaction amount of the coupling agent per unit surface area of the input particles, as in FIG. Even if the temperature was changed to 27 ° C, 47 ° C, and 70 ° C, there was no difference in the reaction amount, so it was found that there was no effect of this range of temperature.

In order to confirm how the reacting coupling agent is attached to the particle surface, an absorption spectrum on the particle surface was measured by FT-IR (Nicolet NEXUS 470, Thermo Electon Co., Ltd.). Here, particles obtained by drying the solvent of the dispersion obtained by stirring with a bead mill were used as samples. The surface of the particles before the surface modification with the coupling agent had OH groups extending from Si, and this peak was sharply measured as an isolated SiOH peak. After stirring with a bead mill and surface modification with a coupling agent, the isolated SiOH peak was small on the particle surface, and it was found that the OH groups present at the beginning reacted. In addition, the coupling agent has CH ₂ , an aromatic ring, and an aromatic secondary amine due to its structure. When each peak was confirmed, a large peak was confirmed for the first particle. From the above results, it was found that the coupling agent was attached by chemical bonding through the OH group present on the particle surface. That is, it was found that the surface modification was performed in a stable state.
In the sample when stirring with a stirrer, to confirm how the coupling agent is attached to the particle surface, FT-IR (Nicolet NEXUS 470, Thermo Electon Co., Ltd.) Absorption spectrum was measured. Here, particles obtained by drying the solvent of the dispersion obtained by stirring were used as samples. As in FIG. 11, it was confirmed that the sharp peak of the OH group existing on the surface of the first particle was small. Moreover, since the peaks of CH ₂ , aromatic ring, and aromatic secondary amine are large, the presence of a coupling agent was confirmed. However, when compared with the peak of the sample stirred with the bead mill, it was confirmed that the peaks of CH ₂ , aromatic ring, and aromatic secondary amine were small when stirred with the stirrer. Therefore, it was confirmed that when the mixture was stirred with a bead mill, the reaction amount of the coupling agent was larger than that of the stirrer as described in FIG.

In order to confirm whether the prepared sample (used particles: 80% by mass SiO ₂ /20% by mass TiO ₂ ) is dispersed as fine particles, the particle size is measured by a dynamic light scattering particle size distribution analyzer (HP5001, Malvern Instruments Ltd). Distribution was measured. In this figure, the vertical axis represents the volume-based integration ratio, and the horizontal axis represents the particle diameter. In addition, there is a vertical dotted line in FIG. 13 and there is a description that the primary particle diameter is 22 nm. This is the particle diameter calculated from the value obtained by BET measurement (specific surface area measurement) in the state of the powder of the used particles. It is. In the case of microparticles, this particle size is almost the same as the particle size observed with an electron microscope. As shown in Examples 11 to 14 and Comparative Example 19, the stirring time in the bead mill was set to 0h, 1h, 4h, 6h, and 8h. It was confirmed that the particle diameter decreased as the stirring time increased. Especially after 8 hours of stirring, since the size is on the order of nanometers, it is possible to produce a solution in which almost all the fine particles that have been intensively aggregated from the initial powder state are dispersed to the size of one particle. did it. Particles can be dispersed even in particles different from the SiO ₂ particles shown in FIG. 1, and it was confirmed that the present invention has high applicability.

FIG. 14 shows the 50% and 80% particle diameters from FIG. 13, and FIG. In addition, the value of 100 nm in the notes in Table 2 was obtained by interpolation from the values of 300 min and 480 min. Both 50% and 80% particle sizes were found to decrease significantly over time. In particular, after stirring for 8 hours, the particle sizes of 50% and 80% are 6.8 nm and 16 nm, respectively, and a dispersion with a very sharp particle size distribution can be produced for 80% by mass SiO ₂ /20% by mass TiO ₂ particles. I understood.

In order to confirm whether the pH of the water added in the preparation of the sample affects the dispersibility and whether the dispersion state of the obtained solution is stable, the pH of the water to be added is set as shown in Example 15. The sample which was set to 3 and stirred for 8 hours with a bead mill was prepared. The particle size distribution of this sample was measured with a dynamic light scattering particle size distribution analyzer. The result is shown in FIG. In this figure, the vertical axis represents the volume-based integration ratio, and the horizontal axis represents the particle diameter. The pH of the water to be added is obtained similar particle size distribution be changed it could be confirmed for the case of 80 wt% SiO _2/20 wt% TiO ₂ particles.

It is a figure which shows the measurement result of dynamic light scattering particle size distribution. It is a figure which shows the measurement result of dynamic light scattering particle size distribution. It is a figure which shows the magnitude | size of a coupling agent. It is a figure which shows the measurement result of dynamic light scattering particle size distribution. It is a figure which shows the measurement result of dynamic light scattering particle size distribution. It is a figure which shows the measurement result of dynamic light scattering particle size distribution. It is a figure which shows the influence of chemical surface modification. It is a figure which shows the influence of physical crushing. It is a figure which shows the reaction amount of a coupling agent. It is a figure which shows the influence of the temperature in a coupling reaction. It is a schematic drawing illustrating the analytic results of the SiO ₂ particle surface. It is a schematic drawing illustrating the analytic results of the SiO ₂ particle surface. It is a figure which shows the measurement result of dynamic light scattering particle size distribution. It is a figure which shows the measurement result of dynamic light scattering particle size distribution. It is a figure which shows the measurement result of dynamic light scattering particle size distribution.

Claims (28)

There is a surface modifier on the surface of the particles made of inorganic oxide,
Inorganic oxide particles having a 50% particle size in the range of 8.9 to 545 nm. Inorganic oxides are Si, Ti, W, V, Y, Ag, Mg, Al, Fe, Ni, Ce, Co, Mo, Au, Pt, Ta, Lu, Zr, Cu, Zn, Pd, Cd, Cr The inorganic oxide particle according to claim 1, wherein the oxide is one of oxides selected from Nb, Pb, and Mn, or an oxide of a combination of any two or more thereof. The inorganic oxide particle according to claim 1, wherein the surface modifier is a coupling agent or a surfactant. The coupling agent is a compound represented by the following general formula: SiR _x (OR ′) _4-x
In this general formula, R 1 represents a vinyl group; an allyl group; a 3-glycidoxypropyl group; a 2- (3,4-epoxycyclohexyl) ethyl group; a 3-acryloxypropyl group; a 3-methacrylopropyl group; 3-aminopropyl group; N-2 (aminoethyl) 3-aminopropyl group; N-phenyl-3-aminopropyl group; alkyl group having 1 to 20 carbon atoms; one kind selected from phenyl group; Or it is 2 or more types.
In this general formula, R ′ is an alkyl group having 1 to 20 carbon atoms; one or more selected from a phenyl group and a methylcarboxy group.
The inorganic oxide particle according to claim 3. The surfactant is any one selected from anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants, or a combination of any two or more thereof. Inorganic oxide particles. The inorganic oxide particles according to claim 1, wherein the 80% particle size is in the range of 16 to 982 nm. The inorganic oxide particle according to claim 1, wherein the amount of the surface modifier reacted per particle unit surface area is in the range of 3.0 to 8.0 μmol / m ² . There is a surface modifier on the surface of the particles made of inorganic oxide,
An inorganic oxide particle dispersion containing inorganic oxide particles having a 50% particle size in the range of 8.9 to 545 nm. Inorganic oxides are Si, Ti, W, V, Y, Ag, Mg, Al, Fe, Ni, Ce, Co, Mo, Au, Pt, Ta, Lu, Zr, Cu, Zn, Pd, Cd, Cr The inorganic oxide particle dispersion according to claim 8, which is any one oxide selected from the group consisting of Pb, Mn, and an oxide of any combination of two or more. The inorganic oxide particle dispersion according to claim 8, wherein the surface modifier is a coupling agent or a surfactant. The coupling agent is a compound represented by the following general formula: SiR _x (OR ′) _4-x
In this general formula, R 1 represents a vinyl group; an allyl group; a 3-glycidoxypropyl group; a 2- (3,4-epoxycyclohexyl) ethyl group; a 3-acryloxypropyl group; a 3-methacrylopropyl group; 3-aminopropyl group; N-2 (aminoethyl) 3-aminopropyl group; N-phenyl-3-aminopropyl group; alkyl group having 1 to 20 carbon atoms; one kind selected from phenyl group; Or it is 2 or more types.
In this general formula, R ′ is an alkyl group having 1 to 20 carbon atoms; one or more selected from a phenyl group and a methylcarboxy group.
The inorganic oxide particle dispersion according to claim 10. The surfactant is any one selected from anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants, or a combination of any two or more thereof. Inorganic oxide particle dispersion. The inorganic oxide particle dispersion according to claim 8, wherein the 80% particle size is in the range of 16 to 982 nm. The inorganic oxide particle dispersion according to claim 8, wherein the amount of the surface modifier reacted per particle unit surface area is in the range of 3.0 to 8.0 μmol / m ² . A method for producing inorganic oxide particles, in which particles comprising an inorganic oxide and a solution containing a surface modifier are stirred by a wet medium mill. Inorganic oxides are Si, Ti, W, V, Y, Ag, Mg, Al, Fe, Ni, Ce, Co, Mo, Au, Pt, Ta, Lu, Zr, Cu, Zn, Pd, Cd, Cr The method for producing inorganic oxide particles according to claim 15, wherein the oxide is any one oxide selected from the group consisting of Pb, Mn, and a combination of any two or more thereof. The method for producing inorganic oxide particles according to claim 15, wherein the surface modifier is a coupling agent or a surfactant. The coupling agent is a compound represented by the following general formula: SiR _x (OR ′) _4-x
In this general formula, R 1 represents a vinyl group; an allyl group; a 3-glycidoxypropyl group; a 2- (3,4-epoxycyclohexyl) ethyl group; a 3-acryloxypropyl group; a 3-methacrylopropyl group; 3-aminopropyl group; N-2 (aminoethyl) 3-aminopropyl group; N-phenyl-3-aminopropyl group; alkyl group having 1 to 20 carbon atoms; one kind selected from phenyl group; Or it is 2 or more types.
In this general formula, R ′ is an alkyl group having 1 to 20 carbon atoms; one or more selected from a phenyl group and a methylcarboxy group.
The manufacturing method of the inorganic oxide particle of Claim 17. The surfactant is any one selected from an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant, or a combination of any two or more thereof. A method for producing inorganic oxide particles. The method for producing inorganic oxide particles according to claim 17, wherein in the addition of water, the ratio of the number of moles of water to the number of moles of alkoxy groups contained in the coupling agent is in the range of 0.1 to 5. The method for producing inorganic oxide particles according to claim 15, wherein the wet medium mill is a bead mill. A method for producing an inorganic oxide particle dispersion, in which particles comprising an inorganic oxide and a solution containing a surface modifier are stirred by a wet medium mill. Inorganic oxides are Si, Ti, W, V, Y, Ag, Mg, Al, Fe, Ni, Ce, Co, Mo, Au, Pt, Ta, Lu, Zr, Cu, Zn, Pd, Cd, Cr 23. The method for producing an inorganic oxide particle dispersion according to claim 22, wherein the oxide is any one oxide selected from the group consisting of Pb, Mn, and a combination of any two or more thereof. The method for producing an inorganic oxide particle dispersion according to claim 22, wherein the surface modifier is a coupling agent or a surfactant. The coupling agent is a compound represented by the following general formula: SiR _x (OR ′) _4-x
In this general formula, R 1 represents a vinyl group; an allyl group; a 3-glycidoxypropyl group; a 2- (3,4-epoxycyclohexyl) ethyl group; a 3-acryloxypropyl group; a 3-methacrylopropyl group; 3-aminopropyl group; N-2 (aminoethyl) 3-aminopropyl group; N-phenyl-3-aminopropyl group; alkyl group having 1 to 20 carbon atoms; one kind selected from phenyl group; Or it is 2 or more types.
In this general formula, R ′ is an alkyl group having 1 to 20 carbon atoms; one or more selected from a phenyl group and a methylcarboxy group.
The manufacturing method of the inorganic oxide particle dispersion of Claim 24. The surfactant is any one selected from an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant, or a combination of any two or more thereof. A method for producing an inorganic oxide particle dispersion. The method for producing an inorganic oxide particle dispersion according to claim 24, wherein in the addition of water, the ratio of the number of moles of water to the number of moles of alkoxy groups contained in the coupling agent is in the range of 0.1 to 5. The method for producing an inorganic oxide particle dispersion according to claim 22, wherein the wet medium mill is a bead mill.

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