JP2009137798A - Method and apparatus for manufacturing spherical inorganic substance powder and method for preparing resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing spherical inorganic substance powder the agglomeration and adhesion of which are restrained. <P>SOLUTION: The method for manufacturing spherical inorganic substance powder includes: a surface treatment step of contacting HMDS (hexamethyldisilazane) with raw inorganic substance powder to obtain treated raw inorganic substance powder; and a conveyance step of conveying the treated raw inorganic substance powder together with a carrier gas; a fusion step of dispersing, heating and melting the conveyed treated raw inorganic substance powder in a high-temperature flame; and a solidification step of withdrawing the molten raw inorganic substance powder from the high-temperature flame and cooling/solidifying the withdrawn raw inorganic substance powder, when a fusion process is adopted. When a VMC process is adopted, the method for manufacturing spherical inorganic substance powder comprises: the surface treatment step; the conveyance step; a burning step of dispersing and burning the conveyed treated raw inorganic substance powder in the high-temperature flame; and a solidification step of withdrawing the burned raw inorganic substance powder from the high-temperature flame and cooling/solidifying the withdrawn raw inorganic substance powder. According to this manufacturing method, since the surface of the raw inorganic substance powder is treated with HMDS, the powder characteristics of the raw inorganic substance powder can be improved and the agglomeration among the raw inorganic substance powders and the adhesion of the raw inorganic substance powder to a conveyance route can be prevented. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a spherical inorganic powder manufacturing method, a spherical inorganic powder manufacturing apparatus, and a resin composition manufacturing method.

  Examples of the method for producing the spherical inorganic powder made of silica or alumina include a method (VMC method) obtained by oxidizing a corresponding metal powder in an oxygen-containing atmosphere, a flame melting method, and the like.

  In the VMC method, a chemical flame is formed by a burner in an atmosphere containing oxygen, and an amount of metal powder that forms part of the target oxide particles is added to the chemical flame so that a dust cloud is formed. This is a method for obtaining spherical oxide particles by deflagration.

  In the flame melting method, the metal oxide constituting the target spherical metal oxide particles is pulverized by pulverization or the like, and then charged and dissolved in a flame. It is a manufacturing method.

  Regardless of which method is used, it is necessary to transport the raw material powder into the flame. In this case, pulsation may occur due to causes such as the raw material powder agglomerating or adhering to the transportation path, and transportation may not proceed smoothly.If transportation does not proceed smoothly, the production conditions will change greatly and the desired properties Thus, a spherical inorganic powder having a particle size cannot be obtained.

As a conventional technique for dealing with this problem, there is a method for producing a spherical inorganic fine powder in which an inorganic raw material powder is sprayed into a flame to form a spheroid, and the surface of the dispersion system is applied to the inorganic raw material powder having an average particle size of 0.5 to 3 μm After mixing the treatment agent, spraying on the flame of the thermal spray burner prevents the inorganic raw material powder from adhering to the thermal spray burner and piping, and prevents increase of particles during thermal spraying due to aggregation of the raw material powder. A manufacturing method and manufacturing apparatus for spherical inorganic fine powder characterized by the above is disclosed (Patent Document 1). Patent Document 1 discloses a silane coupling agent as a dispersion surface treatment agent.
JP 2007-15588 A

  By the way, the present applicant has conventionally manufactured spherical inorganic fine powder, and has established a method for preventing pulsation by preventing the occurrence of aggregation and adhesion in the process.

  SUMMARY OF THE INVENTION The present invention is disclosed in view of the above circumstances, and a manufacturing method and manufacturing apparatus for spherical inorganic powder that suppresses aggregation and adhesion of powder with a novel processing agent different from the prior art, and a manufacturing method thereof. It is a problem to be solved to provide a method for producing a resin composition having a step of producing spherical inorganic powders.

The method for producing a spherical inorganic powder of the present invention includes a surface treatment step of bringing a raw material inorganic powder into contact with an organosilazane to form a treated raw material inorganic powder,
A conveying step of conveying the treated raw material inorganic powder together with a carrier gas; a melting step of dispersing the heated treated raw material inorganic powder in a high-temperature flame and heating and melting; and the molten treated raw material inorganic powder. And a spheronization step having a solidification step of cooling and solidifying by taking out from the high-temperature flame.

  In this case, it is effective when the volume average particle diameter of the raw material inorganic powder is 0.1 μm to 5.0 μm.

And the manufacturing method of the other spherical inorganic powder of the present invention is a surface treatment step for bringing a raw material inorganic powder made of metal into contact with an organosilazane to form a treated raw material inorganic powder,
A conveying step of conveying the treated raw material inorganic powder together with a carrier gas; a combustion step of dispersing the conveyed treated raw material inorganic powder in a high temperature flame and burning; and the treated raw material inorganic powder burned A spheronization process having a solidification process in which it is taken out from the high-temperature flame and solidified by cooling;
It is characterized by having.

  That is, the spherical inorganic powder production method of the present invention improves the powder characteristics of the raw inorganic powder by surface treatment with organosilazanes, prevents aggregation between the powders, and the powder is transported. To prevent adhesion. Organosilazanes exhibit the same or superior adhesion / aggregation preventing effect as compared with silane coupling agents.

Here, the surface treatment step is preferably a step in which 0.05 μmol to 5 μmol of the organosilazane is contacted per 1 m ² of the surface area of the raw inorganic powder. The organosilazane is preferably hexamethyldisilazane.

  The resin composition produced by the method for producing a resin composition of the present invention that solves the above problems comprises a spherical inorganic powder and an organic resin material in which the spherical inorganic powder is dispersed, and the spherical inorganic powder. Is characterized by being produced by the above-described method for producing a spherical inorganic powder of the present invention.

Further, the spherical inorganic powder manufacturing apparatus of the present invention that solves the above-mentioned problems is a surface treatment means for bringing a raw material inorganic powder into contact with an organosilazane to form a treated raw material inorganic powder,
Raw material transport means having a raw material transport path for transporting the treated raw material inorganic powder with a carrier gas;
The treated raw material inorganic powder is conveyed inside by the raw material conveying means and has an internal space having a flame generating device for generating a high temperature flame, and the conveyed treated raw material inorganic powder is heated. A heating furnace;
Unloading means for unloading the inorganic powder after heat treatment from the inside of the heating furnace;
It is characterized by having.

  Since the manufacturing method and the manufacturing apparatus of the spherical inorganic powder of the present invention adopt the above configuration, the following effects are exhibited. That is, by treating the organosilazane in contact with the surface, it is possible to effectively suppress mutual aggregation and adhesion to the transport path in the raw inorganic powder.

(Method for producing spherical inorganic powder)
Hereinafter, the manufacturing method of the spherical inorganic powder of the present invention will be described in detail according to the embodiment. The manufacturing method of the spherical inorganic substance powder of this embodiment is applied to (1) melting method and (2) VMC method. Note that the melting method and the VMC method are not exclusive manufacturing methods, and can be combined as a configuration as described in the VMC method. In other words, it is possible to change the production conditions by mixing the inorganic material constituting the spherical inorganic powder produced in the raw material inorganic powder to be combusted by the VMC method, so that the spherical inorganic material having various properties can be obtained. Powder can be manufactured.

(1) Melting Method The method for producing a spherical inorganic powder according to this embodiment is a method for producing a spherical inorganic powder by heating and melting the raw inorganic powder, and includes a surface treatment step and a spheroidizing step. The form of the raw material inorganic powder is not particularly limited, but the particle size (particle size distribution) of the spherical inorganic powder produced varies depending on the particle size (particle size distribution) of the raw material inorganic powder. The particle size (particle size distribution) is set so that the particle size distribution can be realized.

  The raw inorganic powder is formed from a material capable of forming a spherical inorganic powder after melting and solidification. When producing a spherical inorganic powder formed from an inorganic material that does not change due to melting and solidification, a raw material inorganic powder composed of the inorganic material is employed. For example, when the spherical inorganic powder is formed from a metal oxide (such as silica or alumina), a raw material inorganic powder composed of the metal oxide can be used. In addition, a mixture such as a low-melting glass can be employed as the raw inorganic powder. Furthermore, you may mix the compound volatilized by heating like a certain kind of organic substance.

  Since the raw material inorganic powder having a volume average particle size of 0.1 μm to 5.0 μm is likely to cause adhesion and aggregation in the transportation path, it is desirable to employ the manufacturing method of this embodiment.

The surface treatment step is a step of bringing a raw material inorganic powder into contact with an organosilazane to obtain a treated raw material inorganic powder. The organosilazanes are not particularly limited as long as they are compounds having Si—NH—Si bonds and having one or more hydrocarbon groups. Examples thereof include disilazane: (R ₃ Si) ₂ NH and cyclosilazane: (R ₂ SiNH) _n . Here, all R are independently selectable hydrocarbon groups. In particular, it is desirable to employ hexamethyldisilazane (HMDS). The organosilazanes are preferably used in the range of 0.05 to 5 μmol, more preferably in the range of 0.07 to 3 μmol per 1 m ² of the surface area of the raw inorganic powder. Here, the surface area of the raw inorganic powder was measured by the BET method using nitrogen gas.

  The method for bringing the organosilazane into contact with the raw material inorganic powder is not particularly limited. For example, when the organosilazane is in a liquid state, it can be mixed as it is or as a solution using some solvent. In particular, by adding organosilazanes with good stirring in a mixer or pulverizer, it can be more uniformly adhered to the surface of the raw material inorganic powder. The method for adding the organosilazanes is not particularly limited, but it is desirable to add the organosilazanes atomized using a sprayer as they are or as a solution using some solvent. In addition, a part of the raw material inorganic powder can be processed by bringing the organosilazane into contact with the surface of the raw material inorganic powder and then mixing the remaining raw material inorganic powder with the remaining raw material inorganic powder. Here, the organosilazanes may be those that are simply attached to the surface of the raw material inorganic powder, or those that undergo a chemical reaction with the surface of the raw material inorganic powder.

  The spheronization process has a conveyance process, a melting process, and a solidification process. After the raw material inorganic powder is transported in the transporting process, the raw material inorganic powder is melted and spheroidized in the melting process, and the melted raw material inorganic powder is solidified in the solidifying process.

  The transporting process is a process of transporting the processed raw material inorganic powder together with the carrier gas. The processed raw material inorganic powder stored in a hopper or the like is conveyed by being supplied into a transport path through which a carrier gas is circulated. As the carrier gas, a gas that does not cause an undesired reaction with the treated raw inorganic powder is selected. Nitrogen, air, oxygen, rare gases such as argon can be employed. In particular, it is desirable to use nitrogen or air from the viewpoint of cost unless it is a raw material inorganic powder composed of a highly reactive material, especially when transporting at room temperature.

  The melting step is a step of dispersing and heating the processed raw material inorganic powder in a high-temperature flame. The melting step is preferably performed in a heating furnace. Although a heating furnace is not specifically limited, It is desirable to select the material which comprises the wall of a heating furnace according to the purity requested | required of the spherical inorganic powder to manufacture. For example, when the spherical inorganic powder to be manufactured is required to have a uranium concentration of a predetermined value or less, the wall of the heating furnace in which the raw inorganic powder and the spherical inorganic powder may come into contact with each other It is desirable to control the uranium concentration in the material that constitutes low.

  The solidification step is a step in which the raw material inorganic powder heated and melted in the melting step is recovered from the flame and cooled and solidified. In order to cool and solidify, it is necessary to collect the spheroidized raw material inorganic powder from the flame, but the method of collecting from the flame is not limited.

  The following processes can be mentioned as an example of a coagulation process. Since the raw inorganic powder dispersed in the flame in the melting process is melted by the heat of the flame and then descends by its own weight, the temperature of the space below is lowered without forming a flame below the heating furnace. Thus, it is possible to employ a process in which the raw inorganic powder that has been melted and spheroidized is solidified in the lower space of the heating furnace. When this configuration is adopted, the spherical inorganic powder formed by cooling and solidification can be recovered by sucking the contents from a recovery port formed below the heating furnace, for example, below.

(2) VMC method The manufacturing method of the spherical inorganic powder of the present embodiment is such that the raw inorganic powder made of metal is burned in a flame, and the metal and the atmospheric gas in the flame are reacted, thereby causing the spherical inorganic powder to react. A method for producing a powder, which includes a surface treatment step and a spheronization step. The form of the raw material inorganic powder is not particularly limited, but the particle size (particle size distribution) of the spherical inorganic powder produced varies depending on the particle size (particle size distribution) of the raw material inorganic powder. The particle size (particle size distribution) is set so that the particle size distribution can be realized.

  The metal constituting the raw inorganic powder is a material capable of forming a spherical inorganic powder after burning. For example, when the spherical inorganic powder is formed from a metal oxide (such as silica or alumina), a raw material inorganic powder composed of the corresponding metal (silicon, aluminum) is used. The purity of these metals is adjusted according to the purity required for the spherical inorganic powder finally produced. And as raw material inorganic substance powder, not only a single metal but the mixture of a some metal may be sufficient as needed. Moreover, you may mix the compound volatilized by combustion like a certain kind of organic substance.

  Further, if necessary, a powder formed from an inorganic substance (for example, silica, alumina, etc.) constituting the spherical inorganic powder can be contained in the raw inorganic powder (adopting a structure similar to the melting method). In that case, it is desirable to treat the powder with organosilazanes.

  The surface treatment step is a step of bringing a raw material inorganic powder into contact with an organosilazane to obtain a treated raw material inorganic powder. Since this surface treatment process is the same as the surface treatment process in the melting method described above except that the kind of raw material inorganic powder to be treated is different, further explanation is omitted.

  The spheronization process includes a conveyance process, a combustion process, and a solidification process. Since the same process as the process demonstrated in the melting method mentioned above can be employ | adopted for a conveyance process and a solidification process, further description is abbreviate | omitted.

  The combustion process is a process in which the processed raw material inorganic powder transported in the transport process is dispersed in a high-temperature flame and burned. The high-temperature flame contains an atmospheric gas containing an element selected according to the elements composing the spherical inorganic powder to be produced. For example, when the inorganic substance constituting the spherical inorganic powder is silica (alumina), the raw inorganic powder is made of silicon (aluminum), and the atmosphere gas is selected to contain oxygen. In the combustion step, silicon in the raw material inorganic powder reacts with oxygen in the atmospheric gas, so that the combustion reaction proceeds to form silica.

(Spherical inorganic powder production equipment)
The spherical inorganic powder manufacturing apparatus of the present embodiment includes a surface treatment unit, a raw material transfer unit, a heating furnace, and an unloading unit. The surface treatment means is means for bringing a raw material inorganic powder into contact with an organosilazane to form a treated raw material inorganic powder. This manufacturing apparatus can be applied to both the melting method and the VMC method described above.

  The raw material transport means is a means having a raw material transport path for transporting the processed raw material inorganic powder with a carrier gas. By treating and treating organosilazanes with the surface of the raw material inorganic powder to form a processed raw material inorganic powder, the processed raw material inorganic powder adheres to the raw material transport path, and the amount of transport is less likely to occur. .

  The heating furnace has an internal space. The internal space is a space in which the processed raw material inorganic powder is conveyed. The treated raw material inorganic powder is heated in the internal space. In the case of the melting method, this heat treatment is a treatment in which the treated raw material inorganic powder is heated and melted, and in the case of the VMC method, the treated raw material inorganic powder is burned.

  There is a flame generator inside the interior space. The flame generator is a device that generates a high-temperature flame, and includes a supply nozzle that supplies a combustible gas and a combustion-supporting gas and opens into the internal space. Examples of the combustible gas include hydrocarbon gases such as methane, propane, and acetylene, hydrogen gas, and examples of the combustion supporting gas include oxygen. In particular, when applied to the VMC method, oxygen used in the VMC method can be supplied by excessively adding oxygen as a combustion support gas. When a gas other than oxygen is used in the VMC method, the gas may be mixed with a carrier gas, a combustible gas and / or a combustion-supporting gas and supplied.

  The unloading means is means for unloading the inorganic powder after the heat treatment from the inside of the heating furnace. For example, a suction device provided with a bag filter or the like can be cited, and this device separates the spherical inorganic powder that floats by sucking the internal gas from an opening opening below the heating furnace.

(Production method of resin composition)
The resin composition produced by the resin composition production method of the present embodiment is a mixture of the spherical inorganic powder and the organic resin material, and the spherical inorganic powder is dispersed in the organic resin material. is there. The resin composition can be used as a semiconductor liquid sealing material for sealing semiconductor elements and electronic devices, as well as substrate materials, adhesives, sealing materials, fillers, resist materials, inorganic pastes, coating agents, precision molding resins. Can be used.

  Since the spherical inorganic powder is as described above, further explanation is omitted. The spherical inorganic powder is preferably contained in an amount of 40% by mass or more, more preferably 50% by mass or more based on the total mass.

  Examples of organic resin materials include epoxy resins, oxirane resins, oxetane compounds, cyclic ether compounds, cyclic lactone compounds, thiirane compounds, cyclic acetal compounds, cyclic thioether compounds, spiro orthoester compounds, vinyl compounds, and the like. It can be used alone or in combination.

  In particular, an epoxy resin is preferable from the viewpoints of availability, handleability, and the like. Although an epoxy resin is not specifically limited, The monomer, oligomer, and polymer which have two or more epoxy groups in 1 molecule are mentioned. For example, biphenyl type epoxy resin, stilbene type epoxy resin, bisphenol type epoxy resin, triphenol methane type epoxy resin, alkyl modified triphenol methane type epoxy resin, dicyclopentadiene modified phenol type epoxy resin, naphthol type epoxy resin, triazine core containing An epoxy resin is mentioned.

  Specific examples other than the epoxy resin include oxirane compounds such as phenyl glycidyl ether, ethylene oxide and epichlorohydrin; oxetane compounds such as trimethylene oxide, 3,3-dimethyloxetane and 3,3-dichloromethyloxetane; tetrahydrofuran, 2 Cyclic ether compounds such as 1,3-dimethyltetrahydrofuran, trioxane, 1,3-dioxofuran, 1,3,6-trioxacyclooctane; cyclic lactone compounds such as β-propiolactone and ε-caprolactone; ethylene sulfide, 3, Thiane compounds such as 3-dimethylthiirane; Thiane compounds such as 1,3-propyne sulfide and 3,3-dimethyl thietane; Cyclic thioether compounds such as tetrahydrothiophene derivatives; Spiro ortho ester compounds obtained by reaction with kuton; spiro ortho carbonate compounds; cyclic carbonate compounds; vinyl compounds such as ethylene glycol divinyl ether, alkyl vinyl ether, triethylene glycol divinyl ether; styrene, vinyl cyclohexene, isobutylene, polybutadiene, etc. An ethylenically unsaturated compound can be illustrated. As a cationically polymerizable compound, an epoxy resin and these compounds can be used alone or in combination.

  As a curing agent to be added when an epoxy resin is employed, a primary amine, a secondary amine, a phenol resin, or an acid anhydride may be used. As a curing catalyst, Bronsted acid, Lewis acid, basic catalyst, or the like may be used. Used. As the basic catalyst, imidazole, dicyandiamide, amine adduct, phosphine, and hydrazide are used.

  The production method of the spherical inorganic powder of the present invention will be described in more detail based on examples.

(Test 1)
Evaluation was carried out using the spherical inorganic powder production apparatus shown in FIG. The part shown in FIG. 1 corresponds to the part of the raw material transfer means and the part of the flame generating device in the heating furnace, and corresponds to the apparatus for realizing the transfer process and part of the melting process in the manufacturing method of the present invention. .

  Air was used as the carrier gas. Carrier gas A was introduced from one end of the conveyance path 22 at a pressure of 0.3 MPa. The amount of carrier gas A introduced was 50 Nm / hour. The other end of the conveyance path 22 is a raw material supply nozzle 221 that opens to the flame generator 3. When the pressure when the test powder corresponding to the treated raw material inorganic powder was not introduced was confirmed with the pressure gauge 23, it was 5 kPa. The test powder was stored in the raw material hopper 10 and introduced into the conveyance path 22 through the raw material supply path 21. The supply rate of the test powder was 200 kg / hour. The conveyance path 22 had an inner diameter of 27.6 mm and a length of 15 m. The flame generating device 3 is connected to a combustible gas supply path 31 that supplies the combustible gas B to the combustible gas nozzle 311 and a combustion support gas supply path 32 that supplies the support gas C to the combustion gas nozzle 321. The flame generating device 3 is disposed in an internal space of a heating furnace (not shown).

  The conveyance state for 30 minutes was observed after the conveyance of the test powder was started. And the pressure gauge 23 measured the average transport pressure after 30 minutes and the dispersion | variation in transport pressure.

<Example 1>
As the raw material inorganic powder, crushed crystal silica having a volume average particle size of 0.8 μm was used. A surface treatment process is performed by spraying hexamethylene disilazane to 0.08 μmol per 1 m ² of the surface area of the raw inorganic powder while stirring the raw inorganic powder into a mixer. The test powder was used for the test. The specific surface area of the raw inorganic powder was 15.0 m ² / g.

<Example 2>
As the raw material inorganic powder, crushed crystal silica having a volume average particle size of 0.8 μm was used. A surface treatment process is performed by spraying hexamethylene disilazane to 0.5 μmol per 1 m ² of surface area of the raw inorganic powder while stirring the raw inorganic powder into a mixer. The test powder was used for the test. The specific surface area of the raw inorganic powder was 15.0 m ² / g.

<Example 3>
As the raw material inorganic powder, crushed crystal silica having a volume average particle size of 0.8 μm was used. While the raw material inorganic powder is put into a mixer and stirred, the surface treatment process is performed by spraying hexamethylene disilazane so as to be 2.0 μmol per 1 m ² of the surface area of the raw material inorganic powder. The test powder was used for the test. The specific surface area of the raw inorganic powder was 15.0 m ² / g.

<Example 4>
As the raw material inorganic powder, crushed crystal silica having a volume average particle size of 1.5 μm was used. A surface treatment process is performed by spraying hexamethylene disilazane to 0.5 μmol per 1 m ² of surface area of the raw inorganic powder while stirring the raw inorganic powder into a mixer. The test powder was used for the test. The specific surface area of the raw inorganic powder was 8.0 m ² / g.

<Example 5>
As the raw material inorganic powder, crushed metal silicon having a volume average particle size of 8.5 μm was used. A surface treatment process is performed by spraying hexamethylene disilazane to 0.5 μmol per 1 m ² of surface area of the raw inorganic powder while stirring the raw inorganic powder into a mixer. The test powder was used for the test. The specific surface area of the raw inorganic powder was 4.5 m ² / g.

<Example 6>
As the raw material inorganic powder, crushed lead-free low melting glass having a volume average particle size of 3.2 μm was used. A surface treatment process is performed by spraying hexamethylene disilazane to 0.5 μmol per 1 m ² of surface area of the raw inorganic powder while stirring the raw inorganic powder into a mixer. The test powder was used for the test. The specific surface area of the raw material inorganic powder was 0.7 m ² / g.

(Comparative Examples 1-4)
Except not performing a surface treatment process, the powder which employ | adopted the material and process in Example 1 and 4-6 was prepared, and it used for the test as a test powder of each comparative example.

(result)
The results are shown in Table 1.

  As is apparent from Table 1, by treating HMDS in contact with the surface, both the average transport pressure and the transport pressure were low, and stable conveyance of the test powder could be realized. In particular, silica (Comparative Examples 1 and 2) not subjected to surface treatment was clogged under the test conditions of this evaluation test, and satisfactory conveyance could not be realized. In addition, when the surface treatment was not performed on the metal silicon and the low melting point glass, the average transport pressure increased to about twice, and the fluctuation amount of the transport amount also increased to 5-6 times.

(Test 2)
(Example 7)
Using the test powder of Example 4, spherical inorganic powder was produced by the melting method. The apparatus shown in FIG. 1 was used. Oxygen was used as carrier gas A. A heating furnace having a heat retaining structure was adopted.

(Example 8)
Using the test powder of Example 6, spherical inorganic powder was produced by the melting method. The apparatus shown in FIG. 1 was used. Oxygen was used as carrier gas A. A heating furnace having a heat retaining structure was adopted.

Example 9
Using the test powder of Example 5, spherical inorganic powder was produced by the melting method. The apparatus shown in FIG. 1 was used. Air was used as carrier gas A. A heating furnace having a heat removal structure was adopted.

(Comparative Example 5)
Using the test powder of Comparative Example 4, spherical inorganic powder was produced by the melting method. The apparatus shown in FIG. 1 was used. Oxygen was used as carrier gas A. A heating furnace having a heat retaining structure was adopted.

(result)
The volume average particle diameter was measured with LA500 manufactured by Horiba. The sphericity is calculated from (Sphericality) = {4π × (Projected area) ÷ (Ambient length) ² } by measuring the projected area and circumference of a predetermined number of particles based on the observation result with SEM. did. The sphericity was determined as an average value after measuring 100 for each spherical inorganic powder of each example and comparative example. The results are shown in Table 2.

  As apparent from Table 2, the spherical inorganic powders of Examples 7 and 8 produced by the melting method using the test powders (Examples 4 and 6) surface-treated with HMDS were used as raw materials. It had a volume average particle diameter that was almost the same as the volume average particle diameter of the powder. This can be presumed to originate from the fact that it became possible to stably supply the test powder as a raw material.

  On the other hand, the volume average of the spherical inorganic powder produced in Comparative Example 5 was the same as Example 8 except that the test powder of Comparative Example 4 that was not treated with HMDS was used. The particle size was 6.0 μm, which was found to be significantly larger than the average particle size of the raw material was 3.2 μm. This is because, in Comparative Example 5, the amount of the test powder as a raw material greatly fluctuates as ± 40 kg / hour, so that stable supply of the test powder is not realized, and the particles of the test powder are not realized. It was presumed that a plurality of particles were fused to a particle size larger than that of the raw material. It can be inferred from the value of sphericity that a plurality is fused. That is, the sphericity of the spherical inorganic powder of Comparative Example 5 is 0.87, and compared with the sphericity of 0.97 of the spherical inorganic powder of Example 8 in which the manufacturing conditions other than the surface treatment are the same. This is a low value, confirming that multiple fusions have progressed.

  As is clear from the results of Example 9, even when a spherical inorganic powder is produced by the VMC method, a spherical inorganic powder having a very stable sphericity of 0.99 is provided. It turns out that is possible.

It is a schematic diagram which shows the outline of the manufacturing apparatus of the spherical inorganic substance powder used in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Raw material hopper 21 ... Raw material supply path 22 ... Conveyance path 221 ... Raw material nozzle 23 ... Pressure gauge 3 ... Flame generator 31 ... Combustible gas supply path 311 ... Combustible gas nozzle 32 ... Combustion gas supply path 322 ... Combustion gas nozzle

Claims (7)

A surface treatment step for bringing a raw material inorganic powder into contact with an organosilazane to form a treated raw material inorganic powder;
A conveying step of conveying the treated raw material inorganic powder together with a carrier gas; a melting step of dispersing the heated treated raw material inorganic powder in a high-temperature flame and heating and melting; and the molten treated raw material inorganic powder. A spheronization step having a solidification step of taking out from the high temperature flame and solidifying by cooling;
A method for producing a spherical inorganic powder characterized by comprising:   The method for producing a spherical inorganic powder according to claim 1, wherein the raw inorganic powder has a volume average particle size of 0.1 to 5.0 µm. A surface treatment step in which organosilazanes are brought into contact with a raw material inorganic powder composed of metal to form a treated raw inorganic powder;
A conveying step of conveying the treated raw material inorganic powder together with a carrier gas; a combustion step of dispersing the conveyed treated raw material inorganic powder in a high temperature flame and burning; and the treated raw material inorganic powder burned A spheronization process having a solidification process in which it is taken out from the high-temperature flame and solidified by cooling;
A method for producing a spherical inorganic powder characterized by comprising: 4. The spherical inorganic powder according to claim 1, wherein the surface treatment step is a step in which 0.05 μmol to 5 μmol of the organosilazane per 1 m ² of surface area of the raw inorganic powder is brought into contact. Method.   The method for producing a spherical inorganic powder according to any one of claims 1 to 4, wherein the organosilazane is hexamethyldisilazane. A method for producing a resin composition comprising a spherical inorganic powder and an organic resin material in which the spherical inorganic powder is dispersed,
The method for producing a resin composition, wherein the spherical inorganic powder is produced by the production method according to claim 1. Surface treatment means for bringing a raw material inorganic powder into contact with an organosilazane to form a treated raw material inorganic powder;
Raw material transport means having a raw material transport path for transporting the treated raw material inorganic powder with a carrier gas;
The treated raw material inorganic powder is conveyed inside by the raw material conveying means and has an internal space having a flame generating device for generating a high temperature flame, and the conveyed treated raw material inorganic powder is heated. A heating furnace;
Unloading means for unloading the inorganic powder after heat treatment from the inside of the heating furnace;
A spherical inorganic powder manufacturing apparatus characterized by comprising:

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