JPH10273305A - Metal oxide powder and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an amorphous metal complex oxide having small metal contamination, high purity, small particle diameter and narrow particle size distribution by pulverizing a gel obtained by carrying out hydrolysis reaction and condensation of a mixture of a silicon alkoxide with an alkoxide of group IV metal of the periodic table without the silicon, and firing the pulverized gel. SOLUTION: This metal oxide powder is produced by adding 0.1-2.0 mol water to 1 mol silicon alkoxide as a proportion, hydrolyzing the alkoxide in the presence of an acid catalyst to provide a partial hydrolyzate, adding an alkoxide of a group IV metal of the periodic table without the silicon, or a mixture of the group IV metal of the periodic table with an alkoxide of a group I-III metal of the periodic table to the partial hydrolyzate to provide a complex alkoxide, further adding 2-100 mol water per 1 mol obtained complex alkoxide, hydrolyzing and condensing the complex alkoxide with added water at (-10) to 80 deg.C to form a gel, drying the get, wet-milling or dry-milling the dried gel, firing the milled gel at 400-1,400 deg.C to provide the objective amorphous metal complex oxide powder having <=2 μm average particle diameter, <=10 μm maximum particle diameter, <=200 ppm total content of Fe, Cr and Ni.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous metal composite oxide having low metal contamination, high purity, small particle size and narrow particle size distribution, and its production.

[0002]

2. Description of the Related Art Conventionally, metal oxide powders used for various applications such as fillers are mainly composed of single components such as crystalline silica and fused silica or raw material powders such as silica sand, alumina, boron and alkali metals. Glass obtained by melting is crushed by a crusher and then crushed by a fine crusher.

[0003]

In particular, as a filler for preparing a transparent or translucent resin composition, a filler whose refractive index matches or is close to that of the resin is required. In this case, the smoothness of the resin composition surface varies depending on the size of the filler particles. In particular, when the resin composition is ground after molding, it significantly affects the glossiness of the ground surface. In addition, the polishing property and the glossiness when polishing the ground surface greatly depend on the particle size. As for the gloss, the greater the ratio of the regular reflection on the polished surface, the higher the gloss, and the gloss decreases as the irregular reflection increases. The ratio of irregular reflection increases as the number of irregularly shaped particles having a large particle diameter increases, and tends to decrease as the particle diameter decreases. Further, particles having a smooth surface such as a sphere have a high specular reflection ratio and a high gloss.

In this application, glass powder produced by a melting method is generally used. However, when glass produced by a melting method contains a metal component other than silicon due to problems such as crystallization. Has many restrictions on its composition. In addition, the glass powder obtained by pulverization generally has a wide particle size distribution, and when mixed with a resin having high transparency and no coloring, the metal contained in the glass powder may color the resin composition, May be reduced. This is thought to be due to the fact that the metal used in the crusher was worn and adhered to the crushed powder when the molten mass of glass was crushed into fine powder, resulting in significant metal contamination from the crusher. In the filler of the inorganic powder used in the field of application materials, reduction in coloring and transparency is not desirable.

[0005] Such coloring of the resin and reduction in transparency are caused by
If the powder is contaminated with metal, wash the powder with an inorganic acid such as hydrochloric acid, nitric acid, sulfuric acid, etc. to remove the mixed metal, or use a simple ball mill made of alumina or alumina lining. Grinding is conceivable. However, removal of metal by acid requires a wet chemical treatment and a drying step, and furthermore, a step of further disintegrating the treated fine powder is required, and purification is very costly and practical. is not. Although metal contamination can be prevented to some extent by using a lined ball mill, pulverization requires a long time. In addition, there is a problem that even if the average particle diameter is reduced, some coarse particles remain and the particle size distribution becomes extremely wide. For this reason, it is necessary to separate coarse particles and fine powder during pulverization. However, these inorganic fine powders are generally easily charged with static electricity, and it is very difficult to pass them through a screen with a fine eye. In particular, when a metal material such as stainless steel is used for the screen, metal contamination may occur in this step. In addition, if air classification is performed, it is difficult to ceramic-line all of the powdered parts due to the structure of the classifier, so that the purpose cannot be substantially achieved.

On the other hand, Japanese Patent Publication No. 5-59043 discloses that spherical particles whose refractive index is adjusted to 1 μm or less by a sol-gel method are produced. It is considered that the obtained particles are agglomerated, but when the agglomeration is broken, the particles easily become fine particles, so that there is little metal contamination, and the surface smoothness derived from the sphere has good gloss and transparency. However, since the spherical particles have a smaller specific surface area and a smoother surface than particles of other shapes, the resin composition formed by kneading with the resin breaks quickly at the interface between the spherical particles and the resin. For this reason, compared to a resin composition containing irregular shaped particles obtained by means such as pulverization as a filler, bending strength, tensile strength, abrasion resistance is inferior, and there is a problem in applications requiring high strength. all right.

Further, as a method of solving the compositional restrictions associated with molten glass and freely selecting the glass composition, a composite alkoxide is prepared from silicon alkoxide and other metal alkoxides, and hydrolyzed and condensed to form a gel. A method of making and using this is being studied. In this method, the obtained gel is calcined and pulverized to produce a metal composite oxide glass powder containing a metal other than silicon. However, also in this case, since the pulverizer is made of iron or stainless steel, metal contamination from the pulverizer occurs at the stage of pulverizing the particles, and a high-purity powder cannot be obtained. For this reason, even when these metal-contaminated powders are made into a resin composition, problems such as coloring and opacity occur, and a transparent or clear color tone resin composition cannot be obtained. As described above, an amorphous metal composite oxide powder that is particularly useful as a filler capable of obtaining a resin composition having an excellent appearance has been desired.

[0008]

Means for Solving the Problems The present inventors have solved the above-mentioned problems, and have found that when used as a filler of a resin composition, the polished surface has good gloss, and there is no reduction in coloring or transparency. Intensive studies were conducted to obtain a composite oxide powder. As a result, the gloss was such that the average particle diameter of the particles was less than 2 μm and the maximum particle diameter was 10 μm.
The following were found to be good. Further, it was found that the dried gel of the metal oxide obtained by the sol-gel method was hard, and exhibited the same effect on the metal as the abrasive. In this case, in order to obtain small particles, it is considered that metal contamination occurs in the pulverization step, which affects the transparency of the compounded resin. Therefore, further studies were made on means for substantially removing metal contamination in the pulverizing step and obtaining fine particles.

As a result, when a gel obtained by a sol-gel reaction using a silicon alkoxide or the like as a raw material is pulverized and fired to obtain amorphous metal composite oxide fine particles, a specific portion of the apparatus is made of ceramic or resin of a specific purity. Can prevent metal contamination in the manufacturing process.
That is, the present invention provides a composite oxide containing silicon and a metal of Group IV of the periodic table other than silicon having an average particle size of 2 μm.
m and an amorphous metal oxide fine particle having a maximum particle size of 10 μm or less. The metal composite oxide powder obtained in the present invention can be an amorphous metal composite oxide powder that remains amorphous even after firing and is free from metal contamination from the pulverization step.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. One of (raw material) First, a silicon alkoxide used in the present invention have the general formula R _'n Si (OR) compound represented by the _4-n
More than a species. Furthermore, a hydrolyzate obtained by hydrolyzing these compounds and a low condensate obtained by hydrolyzing and condensing can be used without any particular limitation. R in the general formula
And R 'are alkyl groups, and lower alkyl groups such as a methyl group, an ethyl group, a propyl group, and a butyl group are preferably used. R and R 'may be the same or different. Also,
Any of n = 0, 1, and 2 can be used. In particular, when n = 0, no organic group remains in the gel, which is preferable.

The alkoxides of Group IV metals other than silicon include Ti (OC ₃ H ₇ ) ₄ , Ti (OC ₄ H ₉ ) ₄ and Ti
(OC ₈ H ₁₇ ) ₄ , Ti (OCH ₃ ) ₄ , (OC ₃ H ₇ ) ₂
Titanium alkoxides such as Ti (C ₅ H ₇ O ₂ ) ₂ and Ti (C ₅ H ₇ O) ₄ ; Ti of these alkoxides is Zr;
Various Group IV alkoxides such as zirconium alkoxides substituted by Ge, Hf, Sb, Pb, etc. and (R ³ O) ₃ M
(R ³ and R ⁴ are alkyl groups represented by ^1- OM ² (OR ⁴ ) ₃ , and a lower alkyl group such as a methyl group, an ethyl group, a propyl group, and a butyl group is preferably used. ¹ and M ² are Group IV metals which may be the same or different.) One or more of Group IV composite alkoxides and the like are mentioned.

The alkoxides of Group I, II and III metals include Group I: NaOCH ₃ , NaOC ₂ H ₅ , and NaOC ₃ H _{7, respectively.}
Sodium alkoxides and the like, and Group 1 alkoxides in which Na of these alkoxides is replaced by Li, K, etc. Group II: Mg (OCH ₃ ) ₂ , Mg (OC ₂ H ₅ ) ₂ , M
g (OC ₃ H ₇ ) ₂ , Mg (OC ₄ H ₉ ) ₂ , Mg (OC ₅ H
₁₁ ) Group II alkoxides substituted by Ca, Sr, Ba, etc. in place of magnesium alkoxides and Mg such as ₂ etc. Group III: Al (OC ₂ H ₅ ) ₃ , Al (OC ₃ H ₇ ) ₃ ,
Aluminum alkoxides such as Al (OC ₄ H ₉ ) ₃ and Group III alkoxides substituted for B in place of Al can be used.

(Partial Hydrolysis of Silicon Alkoxide) One example of a method for obtaining the amorphous metal composite oxide fine particles of the present invention is as follows.
This will be described below. First, among these raw material alkoxides, silicon alkoxides are first partially hydrolyzed. Silicon alkoxide has higher stability than other metal alkoxides. Therefore, when hydrolysis is carried out together with other metal alkoxides, the alkoxides other than the silicon alkoxides proceed with the reaction first and precipitate out, so that a homogeneous composite oxide cannot be obtained. In order to prevent this, first, only the silicon alkoxide is hydrolyzed. The partial hydrolysis can be performed by a known means. For example, first, a silicon alkoxide is diluted with an alcohol, and 0.1 to 2.0 mol of water, usually 1 mol, is added to 1 mol of the alkoxide, using an inorganic acid such as hydrochloric acid or an organic acid such as maleic acid as a catalyst,
It is partially hydrolyzed and condensed to form a silicon alkoxide low condensate. If water remains, a metal oxide component other than silicon may precipitate when an alkoxide complex described later is obtained.
It is preferable that the reaction is carried out in the molar range and under an acid catalyst.

(Preparation of composite metal alkoxide)
When one or more alkoxides of Group IV metals or one or more of Group IV metal alkoxides and Group I to III metal alkoxides are added, they react with the silicon alkoxide low-condensate to form a composite metal alkoxide. Is obtained. The obtained composite metal alkoxide is mainly formed by the reaction of a group IV alkoxide and a group I-III alkoxide having a high reaction rate with an OH group at the terminal of a silicon alkoxide low-condensate, and thus a group IV metal alkoxide is produced. Alkoxides and / or Group I-III metal alkoxides are uniformly dispersed and have high homogeneity. Therefore, as will be described later, the gel obtained by hydrolyzing it is homogeneous, and crystallization hardly occurs even if this gel is fired at a high temperature for a long time. The composite metal alkoxide is hydrolyzed as described below.

The hydrolysis is carried out at a temperature in the range of -10 ° C. to 80 ° C. while stirring the above complex alkoxide, and water is added in the range of 2 mol to 100 mol, preferably 2.5 mol, per mol of alkoxide.
~ 50 mol, most preferably 3-10 mol, are added. In addition, a catalyst for hydrolysis and condensation may not be used, but is preferably used in order to shorten the reaction time. As a catalyst, an inorganic acid such as hydrochloric acid, sulfuric acid, phosphoric acid or nitric acid or an organic acid such as formic acid, acetic acid, maleic acid or tartaric acid is added to water used for hydrolysis in an amount of 0.1 to 1 mol of alkoxide.
001 to 1 molar ratio are added. The hydrolyzate then slowly condenses and begins to gel. Gelation time is 1 hour to 24 hours
Time ranges are preferred.

The mixing ratio of the silicon alkoxide and the alkoxide of another metal is 99: 1 to 50:50 in molar ratio,
Preferably it is from 99: 1 to 60:40. The reason is that silica is difficult to crystallize, but Group IV metal oxides other than silica are easily crystallized, and the mixing ratio in the above range is desirable to easily obtain an amorphous composite oxide.
The mixing ratio of the group IV alkoxide to the group I to III alkoxide in the metals other than silicon is 100: 0.
To 40:60 molar ratio, preferably 100: 0 to 6
0:40 molar ratio. The reason is that the addition of Group I to Group III has the effect of suppressing the crystallization of the Group 4 metal. -Group III metal components are likely to dissolve and adverse effects such as lowering the strength of the resin composition are likely to occur, and the softening point of the oxide particles is lowered so that pores are crushed before the organic substances inside the particles are removed during firing. This is because organic substances are easily trapped inside.

The obtained gel is dried. When handling the gel, a part of the gel breaks, but may be actively broken. As a drying method, a commonly used drying method can be used without any limitation. Since it contains an organic solvent such as alcohol, drying under reduced pressure or a nitrogen flash dryer is generally used in consideration of the safety of ignition. The dried gel is obtained as a lump of several mm.

(Pulverization) The pulverizer is preferably one that can use ceramics and / or resin for the powder contact portion. The type of the mill is not particularly limited as long as it has a good pulverizing effect, but a jet mill which satisfies this requirement has a high pulverizing speed and is easy to obtain a pulverized product having a narrow particle size distribution. However, as described in “Journal of the Society of Powder Technology, 6438 (1969)”, the grinding of a jet mill does not proceed at about 3 μm, and it is difficult to reduce the diameter to less than 2 μm. A ball mill is also a crusher used to make fine powder, but generally when inorganic powder is put into a ball mill and crushed, static electricity is generated and adheres to the device wall, balls, etc. Some are buried in the powder and remain as coarse particles. Therefore, it is possible to make the average particle size smaller than 2 μm, but it is difficult to make the maximum particle size smaller than 10 μm.

To solve these problems, the present inventors have found that it is effective to suspend a dry-pulverized gel powder in a solvent and further finely pulverize it by wet pulverization. A wet mill is a type in which a cylindrical container is filled with grinding media of several centimeters to 0.1 mm, and is crushed while stirring the media with a stirrer. The suspension may be supplied continuously or in a batch manner. It is necessary that the inner surface of the cylindrical container that comes into contact with the media, the agitating blades and the shaft of the agitator are lined with wear-resistant ceramics or resin, and that the metal surface does not contact the media.

The solvent in which the powder is suspended has a low toxicity such as water or alcohol, and has a boiling point of 50 ° C. to 1 which does not react with the powder.
A 50 ° C. organic solvent can be used without any particular limitation. The ratio of the powder in the suspension varies depending on the physical properties of the powder. The higher the ratio of the powder, the better the productivity. However, if the viscosity of the suspension is too high, the operability deteriorates. %, Preferably 5 to 60 wt%, is an efficient ratio. Dry and wet mills are generally made of stainless steel. The present inventor has found that a metal pulverizing section and a stirrer are fast and hard powders and a medium contact section where a hard powder or medium collides at a high speed wear the metal material and become a main cause of contamination. For this reason, it has been found by the present inventors that the use of abrasion-resistant ceramics or a metal part made of ceramics and lined with a specific wear rate has an effect of remarkably preventing contamination. In other words, the abrasion rate is 100 ppm / h or less in abrasion abrasion rate. Preferably it is 50 ppm / h or less.

Here, the abrasion wear rate is a value obtained by the following measuring method. Ball mill Mill material: Urethane lining Mill inner volume: 2000 cc Ball size: φ10 mm Ball filling amount: 1000 cc Water filling amount: 800 cc Mill rotation speed: 90 rpm Test time: 48 hours

In the case of ceramics having a hollow wear rate exceeding 100 ppm / h, the wear of the composite oxide obtained by the above-mentioned method due to the dry gel cannot be substantially neglected, and there is a great possibility that metal impurities are mixed. It has been found by the inventors. On the other hand, it has been found that the use of ceramics having a rubbing wear rate in the above-mentioned range makes it possible to substantially neglect impurity contamination even with a dry gel of a composite oxide. When a resin is used, the content of iron, chromium, and nickel in the resin can be neglected (in particular, in the case of iron, a urethane resin or an epoxy resin which has a high adhesive strength and is preferable among the general resins described above). Even if it is present, the detection limit is 1 ppm or less.) On the other hand, it is preferably used in a portion where there is no problem in strength, such as a gap portion of ceramics, so as not to cause a problem in strength.

The type of ceramic used is not particularly limited, and examples thereof include silicon carbide, silicon nitride, alumina, zirconia, and the like, which have the above-mentioned void wear rate.
The type of resin used is not particularly limited, and examples thereof include various organic resins such as a fluorine resin, an acrylic resin, an epoxy resin, a polyolefin resin, a polyester resin, and a urethane resin. These ceramics and resins are preferably of high purity. Particularly preferably iron,
The total of chromium and nickel is 5000 ppm or less, and more preferably 2000 ppm or less.

It is preferable that substantially all portions of the powder contact portion and the media contact portion are made of these materials when the powder contact portion and the media contact portion are made of ceramics and / or resin. Specifically, coating and lining may be performed with these materials, and members may be manufactured with these materials, but coating and lining are preferable in terms of strength. The thickness of the coating and lining is 0.
It needs more than 01mm. It is preferably at least 0.05 mm. The powder contact portion is a portion where dry gel to be subjected to pulverization comes into contact with, specifically, the inside of the pulverizer main body and the parts attached to the inside and the inlet and outlet nozzles of the pulverizer, and further powder supply. The inside of the apparatus, the inside of the pulverized product collector, and their connection pipes correspond. The media contact portion corresponds to the inner surface of the vessel, the surface of the stirrer, and the media separation portion.

The media substantially contributes to pulverization by a wet pulverizer, and beads such as glass, alumina, silicon carbide, and zirconia are generally used. In some cases, a natural sand such as an Ottawa sand or a ceramic ring is applicable. In particular, in a crushing zone or the like where the powder moves and collides at a high speed, even if there is a small gap between the joints of the ceramics, the metal of the crushing device is worn from there and causes metal contamination. Therefore, for example, if there is a gap in the joint between ceramics due to fabrication or shape even when lining with a ceramic material, fine powder enters into such a very narrow gap and wears the metal, causing metal contamination of the powder. It is preferable to prevent the metal surface from being exposed by filling the gap with a resin or coating the resin with the resin so as to substantially prevent contamination from the manufacturing process. This is because even if these synthetic resins are worn during the pulverization and mixed into the pulverized fine particles, the mixed resin is burned and removed when the dried gel is baked, so that no trace is left in the finished powder.

In a jet mill, a compressed gas such as air or nitrogen gas is jetted from a nozzle at a high speed during the pulverization, and the particles are pulverized by collision of particles. It causes contamination of the pulverized particles. In particular, when the air is compressed, the water vapor in the air is condensed and becomes water droplets and accumulates in the piping. These waters promote the corrosion of pipes and cause rust. In the case of compressing such a wet gas, it is preferable to use the compressed gas after cooling it and removing generated fine water droplets. For rust and oil from the compressor, install a gas filter in the middle of the piping,
Removing rust and oil is effective in preventing powder contamination. It is preferable to use stainless steel piping between the gas filter and the pulverizer from the viewpoint of preventing rust.

The raw material powder is generally introduced into a pulverizing section through a hopper section and a fixed-quantity supply section. The hopper may be lined with ceramic, but lining with resin is also effective because the speed of collision with the powder is not high. In addition, the portion of the metering machine that presses the powder with a strong force is preferably made of ceramics from the viewpoint of preventing abrasion. The type is not limited as long as the pulverized particles are not contaminated with metal. Although it is not particularly limited as to meet these requirements, a bag filter is generally used.

(Firing) The crushed and dried gel has fine pores and is fired for stabilizing the strength and physical properties of the particles.
Although the pores are collapsed by firing, the particle size is reduced, but the specific surface area is reduced because the pores are eliminated. The firing method is not particularly limited, and firing may be performed at 400 to 1400 ° C. by a known method. Since the dried gel contains an organic substance, it is preferable to perform the drying under the condition that oxygen is sufficiently present at the time of firing. The dried gel contains organic matter. When this organic matter is confined inside the particles, it is carbonized and becomes an off-white to black powder.
When the temperature is in the range of from to 800 ° C., it is desirable to perform calcination in the presence of oxygen to remove organic components by decomposition and combustion. Abrasion resin mixed in from the crusher is burned and removed in this temperature range, thereby substantially eliminating contamination from the crusher. In a region exceeding this temperature range, oxygen may or may not be present.

The firing temperature varies depending on the composition of the particles.
When the required temperature is higher than the temperature at which the specific surface area becomes constant by firing and lower than the temperature at which crystallization does not occur by firing, it can be made amorphous. By firing in this manner, the metal composite oxide powder of the present invention can be obtained. That is, the composite oxide containing silicon and a metal of Group IV of the periodic table other than silicon has an average particle size of less than 2 μm and a maximum particle size of 10 μm
The following are amorphous metal oxide powders. Further, the amorphous metal oxide powder having a total content of iron, chromium and nickel of 200 ppm or less can be obtained. This includes silicon and one or more metals of Group IV of the periodic table other than silicon, and may also include one or more metals of Groups I, III and II of the periodic table. It is made of a good oxide.

When a powder containing a large amount of metal impurities such as iron, chromium, and nickel is treated with a silane coupling agent to form a resin composition, the silane coupling agent may be altered and may be colored yellow to brown. When a translucent resin composition is used, this coloring is visually enlarged. In addition, it has been found that if these impurities contaminate the powder in the form of metal powder, the resin composition becomes light gray to black, causing significant deterioration in transparency and sometimes becoming opaque. On the other hand, the metal composite oxide powder of the present invention does not cause such a problem and can provide a resin composition having excellent transparency. As is clear from the following examples, the metal composite oxide powder of the present invention was used as a resin composition, and the glossiness of the ground and polished surface was measured by the method described below. Can be set to 50 or more, more preferably 60 or more, and it is recognized that it has excellent gloss.

The relationship between the glossiness and the particle size is that the average particle size is less than 2 μm, the maximum particle size is 10 μm or less, and the glossiness is 50 μm.
It can be seen that the gloss was excellent. Preferably, the average particle diameter can be 1.5 μm or less, and more preferably, the average particle diameter can be 1 to 0.1 μm. The maximum particle size is 10 μm, preferably 8 μm or less, 6 μm
And it is preferable. The total impurity content of iron, chromium, and nickel is preferably 200 ppm or less, and more preferably 100 ppm or less. Such a metal composite oxide powder of the present invention is amorphous and has a small range of particle size distribution, and can have excellent physical properties of an amorphous shape with almost no metal contamination from the manufacturing process, It is also optimal as a filler for dental fillers and semiconductor encapsulants.

[0032]

The present invention will be described in detail with reference to the following examples. The properties of the particles were measured by the following methods. (1) Particle Size and Standard Deviation of Particle Size Distribution The particle size distribution was measured by “Microtrac” (FRA) (Nikkiso Co., Ltd.) laser diffraction method. (2) Specific surface area BET method Using "Yuasa Monosorb" (manufactured by Yuasa Ionics), the amount of adsorbed nitrogen gas is measured and calculated.

(3) Metal impurities 3 g of the composite oxide was placed in a platinum dish, 1 ml of high-purity sulfuric acid was added, and the mixture was heated while adding high-purity hydrofluoric acid to decompose and remove silica components. I do. This is ICP-AE
Measure with S. The lower limit of detection in this measurement was Fe
0.1 ppm, Cr 0.2 ppm, and Ni 0.5 ppm. (4) Whiteness based on blue reflectance 13 g of powder is taken and kneaded with 8 g of dimethacryloxyethyltrimethoxyhexamethylene diurethane (UDMA) to form a paste. Make the paste 10mm thick and add "S
The blue reflectance is measured using an "M color computer" (manufactured by Suga Test Instruments).

(5) Resin composition Dimethacryloxyethyl trimethylhexamethylene
Camphaquinone (Aldri) was used as a photo-enhancing agent in a monomer prepared by mixing g-urethane (UDA: manufactured by Shin-Nakamura Chemical Co., Ltd.) and triethylene glycol dimethacrylate (TEGDMA: manufactured by Shin-Nakamura Chemical Co., Ltd.) at a ratio of 70:30 (wt%).
ch) 0.5 wt%, N, N-dimethylaminoethyl methacrylate (manufactured by Tokyo Chemical Industry) 0.5 as a reducing agent
The resin monomer was adjusted by adding wt%. γ
-After a filler treatment with methacryloxypropyl trimethoxysilane (manufactured by Nippon Unicar Co., Ltd.), the mixture is kneaded with a resin monomer to obtain a resin composition. After molding the resin composition,
It is cured by irradiating it with a visible light irradiator Ecolight (manufactured by Yoshida) for 60 seconds. (6) Glossiness The glossiness is measured according to JIS standard Z8741 Method 3 using VG-2000 manufactured by Nippon Denshoku Industries Co., Ltd.

Example 1 100 g of ethanol and 18 g of 0.002N hydrochloric acid (1 mol of inner water) were placed in a glass reactor.
Was added and 208 g (1 mol) of silicon tetraethoxide was added while heating to 60 ° C., and the mixture was stirred for 30 minutes to partially hydrolyze silicon tetraethoxide to form a low condensate. Next, 52.1 g (0.136 mol) of zirconium tetra n-butoxide (manufactured by Matsumoto Pharmaceutical Co., Ltd.) containing 20 wt% of n-butanol in a pure amount was added, and the mixture was further stirred for 10 minutes.

To the composite metal alkoxide thus obtained, 90 g (5 mol) of 0.002N hydrochloric acid at 25 ° C. was added, and 1
Hydrolysis with stirring for hours. The hydrolyzed solution was transferred to an enamel vat and aged for 3 hours. The inside of the bat was gelled. This was dried with a vacuum dryer at 150 ° C. For the dried gel, the casing is lined with silicon carbide, the gap is filled with urethane resin, and the air nozzle is a jet mill "STJ-200" (manufactured by Seishin) made of alumina.
Crushed in cm ² . The pulverized particles were white fine powder having an average particle size of 3.2 μm and a maximum particle size of 10.5 μm.

This powder was treated with isopropyl alcohol (I
PA), the suspension was adjusted so that the solid content became 30 wt%, and a stirrer was used in a zirconia-lined vessel using a single-headed sand grinder 1 / 4G (manufactured by Imex Corporation) lined with zirconia and urethane resin. The media was ground for 30 minutes using 0.2 mm zirconia. The average particle size was 0.98 μm, and the maximum particle size was 5.9 μm. This suspension was placed in a vacuum dryer, and the alcohol was evaporated to obtain a white powder. This powder was placed in a quartz dish, heated to 1000 ° C. in an electric furnace while passing air, samples were taken every hour, and baked for 3 hours. The fired powder was a white fine powder, and its specific surface area was measured by the BET method, and was found to be constant at 35 m ² / g.

Further, according to the fluorescent X-ray analysis, the ZrO ₂ content ratio was 12 mol%, which coincided with that calculated from the charged amount. The analysis of metal impurities showed that Fe was 33 ppm, C
r Below the detection limit, Ni was 1.2 ppm, and the total was 34.2 ppm. In addition, Fe, Cr, and Ni contained in silicon tetraethoxide used as a raw material were below the lower detection limit. Zirconium butoxide is Fe 100pp
m, Cr and Ni were below the lower detection limit. When calculated from these figures, substantially no contamination from the manufacturing process was observed. The whiteness of this powder due to blue reflectance was 43, and no coloring was observed. Grinding resin composition,
The polished gloss showed a sufficiently high value of 79, indicating high gloss.

(Comparative Example 1) A dried gel was prepared under the same conditions as in Example 1, and the silicon mill and alumina nozzle of the casing of the jet mill were returned to stainless steel. Hereinafter, processing was performed under the same conditions as in Example 1. The average particle size of the baked product is 3.5
μm, the same as the maximum particle size of 10.5 μm, but the pulverized powder turned gray, and it was found that the stainless steel of the pulverizer was clearly shaved. After calcination, metal analysis shows 241 ppm Fe, 63 ppm Cr, 29 ppm Ni
It was 330 ppm in total. This powder was used as a resin composition and turned dark gray. The whiteness based on the blue reflectance is 21;
Coloring was observed. The gloss was as low as 39.

(Comparative Example 2) A wet grind was performed under the same conditions as in Example 1 except that the vessel made of zirconia lining of the sand grinder was replaced with a stainless steel vessel. The ground suspension became grayish white, and contamination with stainless steel was clearly observed. Fe, Cr, N
The total amount of i was 280 ppm, indicating that contamination was caused by mixing of stainless steel powder. The whiteness of the powder was 25, the average particle size was 1.3, the maximum particle size was 6.2, and the glossiness of the ground surface of the resin composition was 65.

Example 2 As in Example 1, silicon tetraethoxide 208 g (1 mol), ethanol 100
Silicon tetraethoxide was partially hydrolyzed using 0 g and 18 g of 0.002N hydrochloric acid water. Next, titanium tetraisopropionate (manufactured by Matsumoto Pharmaceutical Co., Ltd.) 28.
After adding 4 g (0.1 mol) and stirring for 10 minutes, a silicon-titanium composite alkoxide was obtained. This composite alkoxide was treated in the same manner as in Example 1 and pulverized with a ceramic-lined jet mill to have an average particle size of 2.7 μm.
A white ground gel powder having a maximum particle size of 10.3 μm was obtained. This was adjusted to a solid content of 30 wt% in IPA and pulverized with a sand grinder, and the powder was confirmed to be amorphous by X-ray analysis. The product fired at 1000 ° C. was also amorphous like the dried gel, and the content of TiO ₂ was 9 mol% in the fluorescent X-ray analysis, which coincided with the calculated value. Whiteness 44, average particle size 0.97 μm, maximum particle size 5.9 μm, specific surface area 38 m ² /
g, a silicon-titanium composite oxide having a refractive index of 1.50. The total content of Fe, Cr and Ni was 1.8 ppm. Impurity analysis of the raw material titanium tetraisopropoxide revealed that all of Fe, Cr and Ni were below the lower detection limit. The glossiness of the ground and polished surface of the resin composition was 77.

Example 3 As in Example 1, 1 mol of silicon tetraethoxide was used to prepare a low condensate. Next, 52.1 g of zirconium tetra n-butoxide (0.
136 mol) and 3.8 g of sodium methoxide
(0.1 mol) / (as a methyl alcohol solution) was added to prepare a metal alkoxide complex, which was treated, dried, and wet-pulverized in the same manner as in Example 1. The particles fired at 1000 ° C. are amorphous, white powders having an average particle size of 0.76 μm, a maximum particle size of 5.6 μm, and a whiteness of 43, and Fe, Cr, N
i Total content was 33 ppm. Grinding of resin composition,
The glossiness of the polished surface was 78. (Examples 4 to 6) In the same manner as in Example 1, metal composite oxide powders were obtained under the conditions shown in Table 1.

[0043]

[Table 1]

[0044]

According to the present invention, an amorphous metal oxide powder useful as a filler for a resin composite material having excellent aesthetic appearance can be obtained.

Claims (7)

[Claims] 1. An amorphous metal oxide powder having an average particle size of less than 2 μm and a maximum particle size of 10 μm or less, comprising a composite oxide containing silicon and a metal of Group IV of the periodic table other than silicon. 2. The total content of iron, chromium and nickel is 20.
The amorphous metal oxide powder according to claim 1, wherein the amount is 0 ppm or less. 3. The amorphous metal oxide powder according to claim 1, which is amorphous. 4. The periodic table other than silicon alkoxide and silicon
A mixture with one or more alkoxides of Group IV metals,
Or one or more of silicon alkoxides and alkoxides of metals belonging to Group IV of the periodic table other than silicon,
Amorphous metal composite oxide characterized in that a gel is formed from a mixture with at least one of Group II and Group III metal alkoxides by hydrolysis reaction and condensation, followed by dry pulverization, wet pulverization and calcination. Powder manufacturing method. 5. The method for producing an amorphous metal composite oxide powder according to claim 4, wherein the alkoxide of a metal belonging to Group IV of the periodic table other than silicon is a zirconium alkoxide or a titanium alkoxide. 6. The pulverization of the gel is carried out at a dry abrasion rate of 100 (ppm) by a dry contact pulverization part and a wet pulverization medium contact part.
/ H) The method for producing an amorphous metal composite oxide powder according to claim 4 or 5, wherein the method is carried out using a pulverizer that is the following ceramic and / or resin. 7. The amorphous metal composite oxide according to claim 4, wherein the gel is pulverized by a jet mill, and a gas filter is provided in a piping system of a compressed gas of the jet mill. Powder manufacturing method.