JP6149571B2 - Manufacturing method of glass powder - Google Patents

Description

  The present invention relates to a method for producing glass powder.

  Recently, in order to form a thin and uniform glass coating on the surface of substrates and substrate particles, a technology for easily producing glass powder with nano-order fineness and high sphericity (sphericity) is required. ing. For example, as a core material for motors, actuators, magnetic sensors, etc., soft magnetic particles such as iron powder are mixed with low-melting glass powder and heat-treated after compaction to bond soft magnetic particles with low-melting glass as a binder layer. A soft magnetic composite material is known. In such a soft magnetic composite material, if the above-mentioned fine and high sphericity glass powder can be used as the low melting point glass powder, a higher quality and higher performance soft magnetic composite material can be obtained. it can.

  Various techniques for producing fine spherical glass powder have been proposed so far. For example, Patent Document 1 describes a method of producing a spherical glass powder by spraying droplets in a flame atmosphere and thermally decomposing them. Patent Document 2 discloses a method in which droplets are introduced into a flame part through a connecting tube and vitrified at a temperature outside the flame part to form glass particles.

  However, in the method described in Patent Document 1, the average particle size of the obtained glass powder is about 1 μm, and a fine glass powder smaller than that cannot be obtained. In addition, since the distance between the droplet and the flame varies, there is a problem that the thermal history becomes non-uniform and uniform glass particles cannot be obtained. On the other hand, even in the method described in Patent Document 2, it is difficult to obtain glass powder having an average particle size of nano order because droplets aggregate before reaching the flame part. In addition, since the heat outside the flame part is used, the distance between the droplet and the flame when passing through the flame part varies, and as in the above method, the heat history becomes non-uniform and the homogeneity of the glass particles. Cause problems. Furthermore, in this method, the shape of the glass powder obtained varies and the sphericity is low.

JP-A-8-91874 JP 2004-339046 A

  An object of the present invention is to provide a method capable of easily and stably producing a fine and highly spherical glass powder useful for forming a thin and homogeneous glass coating.

In the method for producing a glass powder according to one embodiment of the present invention, a glass raw material compound containing a plurality of glass constituent elements is completely dissolved in a solvent, and the concentration of the glass raw material compound is 2 to 20 as the total amount of oxide equivalents. preparing a liquid material comprising a mass%, the liquid raw material with a flame or hot air, is ejected into the reaction space, after pyrolysis, characterized in that it comprises the step of quenching.

  According to the present invention, it is possible to easily and stably produce a fine and highly spherical glass powder useful for forming a thin and homogeneous glass film.

It is a figure which shows the process flow of the manufacturing method of the glass powder of one Embodiment of this invention. It is a figure which shows roughly the principal part structure of the apparatus used for one Embodiment of this invention. 2 is a photograph taken by a transmission electron microscope (TEM) of Example 1. 3 is a photograph taken by a transmission electron microscope (TEM) of Example 2. 4 is a photograph taken by a transmission electron microscope (TEM) of Example 3. 4 is a photograph taken by a transmission electron microscope (TEM) of Example 4. 6 is a photograph taken by a transmission electron microscope (TEM) of Example 5. 6 is a photograph taken by a transmission electron microscope (TEM) of Example 6. 10 is a photograph taken by a transmission electron microscope (TEM) of Example 7. 10 is a photograph taken by a transmission electron microscope (TEM) of Example 8. 10 is a photograph taken by a transmission electron microscope (TEM) of Example 9.

  Embodiments of the present invention will be described below. In addition, although description is given based on drawing, those drawings are provided for illustration and this invention is not limited to those drawings at all.

  FIG. 1 is a diagram showing a process flow of a method for producing glass powder according to an embodiment of the present invention.

  As shown in FIG. 1, the glass powder production method of the present embodiment is a method in which a liquid raw material containing a glass raw material compound and a solvent is jetted into a reaction space together with a flame or hot air, thermally decomposed, and then rapidly cooled. . The process includes the following three processes: a process for preparing a liquid source (101), a process for heat-treating the liquid source (102), and a process for collecting and collecting glass powder (103).

[Liquid raw material preparation process]
In the present embodiment, a solution obtained by dissolving or dispersing a glass raw material compound in a solvent is used as the liquid raw material.

  A glass raw material compound is a compound containing an element constituting glass, for example, chloride, nitride, hydrate, organic acid salt (for example, acetate, formate, etc.), organic of each element constituting glass. Compound, oxo acid salt, coordination compound, acid, nitrate, sulfate and the like. The glass raw material compound is preferably selected depending on the solvent to be mixed. For example, when water is used as the solvent, a water-soluble compound such as a chloride, an organic acid salt, or a nitrate is used. Moreover, even if it is insoluble in water, such as an oxide or carbonate, it can be dissolved in an acid or the like.

  Examples of the elements constituting the glass include Si, B, P, Zn, Li, Na, K, Bi, Mg, Ca, Sr, Ba, Al, Sn, Zr, Nb, W, Ga, La, Ti, Ce, V, Cr, Mn, Fe, Co, Ni, Cu, etc. are mentioned.

  Examples of the solvent for dissolving or dispersing the glass raw material compound include water, alcohol (for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isopropyl alcohol, n-pentyl alcohol, 2- Methoxy alcohol, etc.), highly polar solvents such as formic acid, acetic acid, propionic acid; mineral spirit, mineral thinner, petroleum spirit, white spirit, mineral turpentine, kerosene, n-hexane, hexanoic acid, 2-ethylhexanoic acid , Low polar solvents such as cyclohexane, isoheptane, toluene, benzene, xylene.

  Here, specific examples of the glass raw material compound suitable for the high polar solvent include, for example, sodium silicate, tetramethoxysilane, tetraethoxysilane, methyltriethoxysilane, boric acid, phosphoric acid, zinc nitrate, zinc acetate, and chloride. Zinc, lithium nitrate, lithium acetate, lithium chloride, sodium nitrate, sodium acetate, sodium chloride, potassium nitrate, potassium acetate, potassium chloride, bismuth nitrate, magnesium nitrate, magnesium acetate, magnesium chloride, calcium nitrate, calcium acetate, calcium chloride, nitric acid Strontium, barium nitrate, barium acetate, barium chloride, aluminum nitrate, aluminum chloride, zirconia nitrate, niobium nitrate, cerium nitrate, cerium chloride, manganese nitrate, manganese acetate, manganese chloride, iron nitrate, iron acetate, chloride , Cobalt acetate, cobalt chloride, nickel nitrate, cobalt acetate, nickel chloride, copper nitrate, and copper chloride.

  Specific examples of the glass raw material compound suitable for the low-polar dilution solvent include, for example, tetramethoxysilane, tetraethoxysilane, octamethylcyclotetrasiloxane, polydimethylsiloxane, tributyl boride, triphenylphosphine, and triphenylphosphine oxide. , Zinc 2-ethylhexanoate, lithium 2-ethylhexanoate, lithium naphthenate, sodium 2-ethylhexanoate, potassium 2-ethylhexanoate, bismuth 2-ethylhexanoate, magnesium 2-ethylhexanoate, 2-ethyl Calcium hexanoate, strontium 2-ethylhexanoate, barium 2-ethylhexanoate, tris (ethylacetoacetate) aluminum, aluminum-sec-butoxide, aluminum mono-n-butoxydiethyl Acetoacetic acid ester, ethyl acetoacetate aluminum dinormal butyrate, tin (II) octylate, dibutyltin dilaurate, 2-ethylhexanoic acid zirconia, 2-ethylhexanoic acid niobium, niobium ethoxide, niobium butoxide, 2-ethylhexanoic acid Bismuth, tungsten (IV) ethoxide, tungsten (IV) isopropoxide, lanthanum 2-ethylhexanoate, yttrium 2-ethylhexanoate, gadolinium 2-ethylhexanoate, tetraisopropoxytitanium, tetra-n-butoxytitanium, tetra (2-ethylhexyl) titanate, cerium 2-ethylhexanoate, chromium 2-ethylhexanoate, manganese 2-ethylhexanoate, iron 2-ethylhexanoate, copper naphthenate, cobalt 2-ethylhexanoate, 2-ethyl Examples include nickel tilhexanoate.

  The concentration of the glass raw material compound in the liquid raw material is preferably in the range of 1 to 30% by mass, more preferably in the range of 2 to 20% by mass as the total amount of the oxide equivalent of the glass raw material compound. When the concentration of the glass raw material compound is less than 1% by mass, the required amount of solvent increases and the environmental load increases. On the other hand, when it exceeds 30 mass%, it becomes difficult to obtain fine glass powder. Moreover, preparation of a uniform concentration solution becomes difficult and the composition of the obtained glass powder may be non-uniform.

[Heat treatment process for liquid raw materials]
The heat treatment of the liquid material is performed by jetting the liquid material into the reaction space together with a flame or hot air. The liquid raw material ejected together with the flame or hot air forms numerous fine droplets simultaneously with the ejection, and all these droplets are instantaneously and uniformly heated by the heat of the flame or hot air. For this reason, the droplets remain as fine droplets without agglomerating, the solvent is volatilized, and the glass raw material compound dissolved or dispersed in the droplets is uniformly pyrolyzed and vitrified to form a fine and homogeneous glass. Particles are formed. Then, these fine glass particles are solidified as fine and homogeneous particles by the subsequent rapid cooling. Therefore, it is possible to stably obtain a glass powder that is fine and has a high sphericity (sphericity).

  For the generation of the flame, a mixed gas of a flammable gas such as hydrogen gas, propane gas, city gas, and acetylene gas and a flammable gas such as oxygen gas can be used. The flow rate of the mixed gas varies depending on the type of gas used. For example, in the case of a combination of propane gas and oxygen gas, the flow rate of propane gas is preferably in the range of 0.7 to 1.3 NL (normal liters) / min. The range of 0.8 to 1.2 NL / min is more preferable, and the flow rate of oxygen gas is preferably 3 to 6 NL / min, and more preferably 4 to 6 NL / min.

  In the present invention, when a flame is used, it is preferable to supply an oxidizing gas such as oxygen gas or air to the reaction space. By supplying an oxidizing gas, the reaction field (reaction space) of the combustible gas and the combustion-supporting gas can be raised to a higher temperature, and the raw material can be pyrolyzed more quickly to nucleate fine particles. Fine glass particles with high sphericity can be synthesized. The flow rate of the oxidizing gas is preferably in the range of 6 to 18 NL / min, and more preferably in the range of 7 to 15 NL / min.

  Moreover, air, nitrogen gas, etc. can be used for a hot air, for example. The flow rate of hot air is preferably in the range of 10 to 28 NL / min, and more preferably in the range of 12 to 26 NL / min.

  The temperature of the flame and hot air, that is, the heat treatment temperature of the liquid raw material is preferably 1500 ° C. or higher. If the heat treatment temperature is less than 1500 ° C., the thermal decomposition reaction of the glass raw material compound is not sufficiently performed, and there is a possibility that vitrification does not occur or the vitrification becomes insufficient. However, if the temperature is too high, an element having a small atomic weight may be volatilized. Therefore, the heat treatment temperature is more preferably 1600 to 2500 ° C, and even more preferably 1700 to 2500 ° C.

[Glass powder collection and recovery process]
The glass particles generated by the heat treatment process of the liquid raw material are collected and collected using a collection device such as a bag filter.

  The liquid raw material heat treatment step and the glass powder collection / recovery step can be performed using, for example, an apparatus as shown in FIG.

  As shown in FIG. 2, this apparatus is connected to a reaction tube 1 that forms a reaction space, a burner 2 that is detachably attached to a wall on one end side of the reaction tube 1, and the other end side of the reaction tube 1. A recovery device 4 having a bag filter 3 for collecting glass particles generated in the reaction cylinder 1 is provided. Around the reaction tube 1, a cooling pipe 5 through which cooling water flows is disposed as a cooling means. The burner 2 is supplied with a liquid raw material, a mixed gas of combustible gas and combustion-supporting gas, and an oxidizing gas. Further, an exhaust port (not shown) is opened on the downstream side of the recovery device 4, and an exhaust device 6 such as an ejector is connected to the exhaust port.

  In the apparatus shown in FIG. 2, a liquid raw material, a mixed gas of combustible gas and combustion-supporting gas, and an oxidizing gas are ejected from the burner 2 into the reaction tube 1. At that time, the mixed gas is burned to form a flame. Thereby, the liquid raw material and the oxidizing gas are ejected into the reaction tube 1 together with the flame formed by burning the mixed gas. The liquid raw material ejected into the reaction cylinder 1 becomes droplets, but is instantaneously heated by the heat of the flame to cause a thermal decomposition reaction. A cooling pipe 5 is disposed around the reaction tube 1, and the pyrolyzate is rapidly cooled and vitrified when it comes out of the flame. Thus, glass powder is produced | generated when droplets vitrify one after another. The generated glass powder is collected and collected by a collection device 4 having a bag filter 3.

  In this way, a large number of fine droplets are formed simultaneously with the ejection from the liquid raw material ejected into the reaction cylinder 1, and all of these droplets are instantaneously heated by the heat of the flame and emitted the flame. By the way, it is cooled rapidly. For this reason, the droplets are thermally decomposed uniformly and vitrified as fine droplets without agglomeration, and fine and homogeneous glass particles are formed. Further, since the oxidizing gas is ejected from the burner 2 together with the liquid raw material, the reaction field can be raised to a higher temperature, and the raw material can be decomposed more instantly to generate nuclei of fine particles. Therefore, it is possible to stably obtain a glass powder that is fine and has a high sphericity (sphericity).

  The apparatus shown in FIG. 2 ejects the liquid raw material into the reaction space together with the flame, but instead of the burner 2, a device for ejecting hot air and liquid raw material into the reaction space (reaction cylinder 1) is installed. In addition, the liquid raw material that has become droplets can be rapidly cooled after being thermally decomposed by the heat of hot air.

  In this apparatus, the liquid raw material ejected into the reaction cylinder 1 forms a large number of fine droplets simultaneously with the ejection, and these droplets are all heated instantaneously with hot air and then rapidly cooled. For this reason, the droplets are thermally decomposed uniformly and vitrified as fine droplets without agglomeration, and fine and homogeneous glass particles are formed. Therefore, it is possible to stably obtain a glass powder that is fine and has a high sphericity.

  According to the method for producing glass powder of the present invention, glass particles having an average particle size as fine as 500 nm or less and a high sphericity with an average sphericity of 0.7 or more can be obtained.

  Here, the average particle diameter of the glass particles can be obtained by analyzing an image obtained by an apparatus capable of observing a fine structure such as a transmission electron microscope or a scanning electron microscope. It is also possible to measure using a laser diffraction particle size distribution measuring apparatus.

  The glass particles obtained by the present invention preferably have an average particle size of 400 nm or less, and more preferably 300 nm or less.

  The sphericity of the glass powder is defined by a ratio Dmin / Dmax between the minimum diameter Dmin passing through the center of gravity of the glass powder and the maximum diameter Dmax passing through the center of gravity of the glass powder, as measured in a transmission electron micrograph of the glass powder. Therefore, the average sphericity is an average value of sphericity measured for 50 to 100 glass powders arbitrarily selected from transmission electron micrographs. The sphericity indicates that the sphericity is higher as the value of Dmin / Dmax approaches 1.

  The glass particles obtained by the present invention preferably have an average sphericity of 0.7 or more.

  It goes without saying that the present invention is not limited to the description of the embodiment described above, and can be appropriately changed without departing from the gist of the present invention.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all.

Example 1
B ₂ O ₃ 22.0%, ZnO 60.8%, SiO ₂ 11.8%, Al ₂ O ₃ 0.5%, MgO 4.9%, and CeO ₂ 0.1 in terms of mass% based on oxide. % Glass composition such as tributyl boride, zinc 2-ethylhexanoate mineral spirits solution (zinc content: 15.0% by mass), octamethylcyclotetrasiloxane, tris (ethylacetoacetate) aluminum, 2- Magnesium ethylhexanoate Toluene solution (magnesium content: 2.3% by mass), cerium 2-ethylhexanoate (III) 2-ethylhexanoic acid solution (cerium content: 12.0%) was weighed out and used as a solvent. Add 162 ml of mineral spirits, stir for 15 hours to completely dissolve, and prepare a clear, light yellow liquid raw material with an oxide concentration of 4% by mass It was.

  Next, the obtained liquid raw material was supplied to the apparatus shown in FIG. 2 and ejected from the burner to the reaction tube together with the flame to cause a thermal decomposition reaction, and then rapidly cooled to produce glass powder. That is, oxygen gas was supplied to the burner as a combustion-supporting gas at 5 NL / min and propane gas as a flammable gas was supplied at 1 NL / min, and the tip of the burner was ignited to generate a flame (about 1800 ° C.). After this burner was inserted into the reaction cylinder, the liquid raw material was injected at 2.5 g / min, and oxygen gas as an oxidizing gas was injected at 9 NL / min from the center of the burner where the flame was jetted. During the reaction, cooling water was always flowed through a cooling pipe disposed so as to surround the reaction cylinder so that at least the outlet of the reaction cylinder was kept at a low temperature. Then, the produced | generated glass powder was collect | recovered from the collection apparatus.

(Example 2)
In mass% notation oxide _{basis, B 2 O 3 23.0%,} ZnO57.0%, SnO 2 1.0%, SiO 2 8.0%, Al 2 O 3 4.0%, Li 2 O1. Tributyl boride, zinc 2-ethylhexanoate mineral spirits solution (zinc content: 15.0% by mass), tin octylate (II) so as to have a glass composition of 0%, CaO 1.0%, and BaO 5.0% ), Octamethylcyclotetrasiloxane, tris (ethylacetoacetate) aluminum, lithium naphthenate mineral spirits solution (lithium content: 1.16% by mass), calcium 2-ethylhexanoate 2-ethylhexanoic acid solution (calcium content: 4.9 mass%) and barium 2-ethylhexanoate in toluene (barium content: 8.0 mass%) Mineral spirits 144ml was added and stirred for 15 hours to completely dissolve, to prepare a 4 wt% of a clear, pale yellow liquid raw material in oxide concentration.

  A glass powder was produced from the liquid raw material in the same manner as in Example 1 using the apparatus shown in FIG.

(Example 3)
In mass% notation oxide _{basis, B 2 O 3 23.0%,} ZnO49.0%, SnO 2 1.0%, SiO 2 10.0%, Al 2 O 3 2.0%, Na 2 O3. 0%, K ₂ O 4.0%, CaO 3. % And BaO 5.0% so that the glass composition is tributyl borate, zinc 2-ethylhexanoate mineral spirits solution (zinc content: 15.0 mass%), tin (II) octylate, octamethylcyclotetra Siloxane, tris (ethylacetoacetato) aluminum, sodium 2-ethylhexanoate, potassium 2-ethylhexanoate, calcium 2-ethylhexanoate 2-ethylhexanoic acid solution (calcium content: 4.9% by mass), and 2 -Barium ethyl hexanoate Toluene solution (barium content: 8.0% by mass) was weighed and added, and then 149 ml of mineral spirits was added as a solvent and stirred for 15 hours to completely dissolve, and the oxide concentration was 5% by mass. A transparent and pale yellow liquid raw material was prepared.

  A glass powder was produced from the liquid raw material in the same manner as in Example 1 using the apparatus shown in FIG.

Example 4
In mass% notation oxide _{basis, B 2 O 3 4.7%,} ZnO9.6%, P 2 O 5 18.4%, Bi 2 O 3 39.5%, Li 2 O0.8%, ZrO 2 Tributyl boride, zinc 2-ethylhexanoate mineral spirits solution (zinc content: 15.0% by mass), triphenylphosphine, so as to have a glass composition of 3.3% and Nb ₂ O ₅ 23.7% 2-ethylhexanoic acid bismuth 2-ethylhexanoic acid solution (bismuth content: 25.1% by mass), lithium naphthenate mineral spirits solution (lithium content: 1.16% by mass), 2-ethylhexanoic acid zirconia mineral spirits solution ( Zirconia content: 6.00% by mass) and niobium butoxide n-butanol solution (niobium content: 5.01% by mass) were weighed out, Then, 107 ml of mineral spirits was added, and the mixture was stirred for 15 hours to be completely dissolved to prepare a transparent and light yellow liquid raw material having an oxide concentration of 4% by mass.

  A glass powder was produced from the liquid raw material in the same manner as in Example 1 using the apparatus shown in FIG.

(Example 5)
In mass% notation oxide _{basis, B 2 O 3 5.9%,} ZnO10.6%, Al 2 O 3 0.5%, Bi 2 O 3 82.5%, CeO 2 0.2%, Fe 2 Tributyl boride, zinc 2-ethylhexanoate mineral spirits solution (zinc content: 15.0% by mass), ethyl acetoacetate aluminum di-normal so as to have a glass composition of 0.2% O _{3 and} 0.1% CuO A mineral spirits solution of butyrate and aluminum mono-n-butoxydiethylacetoacetate (aluminum content: 5.9% by mass; trade name Kerope (S) -30MT manufactured by Hope Pharmaceutical Co., Ltd.), bismuth 2-ethylhexanoate 2 -Ethylhexanoic acid solution (bismuth content: 25.1% by mass), cerium 2-ethylhexanoate 2-ethylhexanoic acid solution (seric Um content: 12% by mass), iron 2-ethylhexanoate mineral spirits solution (iron content: 8.0% by mass), copper 2-ethylhexanoate mineral spirits solution (copper content: 8.0% by mass) After taking, 349 ml of mineral spirits was added as a solvent, and the mixture was stirred for 15 hours to be completely dissolved, thereby preparing a transparent, black-purple liquid raw material having an oxide concentration of 4% by mass.

  A glass powder was produced from the liquid raw material in the same manner as in Example 1 using the apparatus shown in FIG.

(Example 6)
In mass% notation oxide _{basis, B 2 O 3 23.1%,} ZnO49.2%, CoO0.5%, SiO 2 10.1%, Al 2 O 3 2.0%, Na 2 O3.0% _{, K 2 O4.1%, CaO3.0%} , and so that BaO5.0% of glass composition, boric acid, zinc acetate dihydrate, nitrate Arumuniumu nonahydrate, sodium acetate, potassium acetate, calcium nitrate Tetrahydrate, barium nitrate, and cobalt (II) acetate were weighed out and mixed with 113 ml of purified water as a solvent, and stirred for 1 hour to completely dissolve. Thereafter, methyltriethoxysilane was weighed and collected, and then added to the aqueous solution and stirred for 1 hour until uniform. Further, 56 ml of ethanol was added and stirred for 30 minutes to prepare a transparent and light pink liquid raw material having an oxide concentration of 4% by mass.

  A glass powder was produced from the liquid raw material in the same manner as in Example 1 using the apparatus shown in FIG.

(Example 7)
In mass% representation on the oxide _{basis, P 2 O 5 46.4%,} Al 2 O 3 5.3%, so that BaO47.5%, and CoO0.8% of the glass composition, triphenylphosphine, Keropu (S) -30MT, barium 2-ethylhexanoate Toluene solution (barium content: 8.0% by mass) and cobalt 2-ethylhexanoate (cobalt content: 12.0% by mass) were weighed out and used as a solvent. Mineral spirits (146 ml) and toluene (36 ml) were added and stirred for 15 hours to completely dissolve them, thereby preparing a transparent, black-purple liquid raw material having an oxide concentration of 5% by mass.

A glass powder was produced from the liquid raw material in the same manner as in Example 1 using the apparatus shown in FIG.

(Example 8)
In mass% notation oxide _{basis, B 2 O 3 20.1%,} ZnO42.7%, SnO 2 0.9%, SiO 2 8.7%, Al 2 O 3 1.8%, Na 2 O2. Tributyl boride, zinc 2-ethylhexanoate mineral spirits solution to have a glass composition of 6%, K ₂ O 3.5%, CaO 2.6%, BaO 4.4%, and Fe ₂ O ₃ 12.7% (Zinc content: 15.0% by mass), tin (II) octylate, octamethylcyclotetrasiloxane, kelope (S) -30MT, sodium 2-ethylhexanoate, potassium 2-ethylhexanoate, 2-ethylhexanoic acid Calcium mineral spirits solution (calcium content: 4.1% by mass) and barium 2-ethylhexanoate mineral spirits solution (barium content: 15.0% by mass) , Iron 2-ethylhexanoate Mineral spirits solution (iron content: 8.0% by mass) was weighed and added, and then 437 ml of mineral spirits was added as a solvent, stirred for 15 hours to completely dissolve, and an oxide concentration of 5 masses. % Black purple liquid raw material was prepared.

  A glass powder was produced from the liquid raw material in the same manner as in Example 1 using the apparatus shown in FIG.

Example 9
In mass% representation on the oxide _{basis, SiO 2 29.2%, K 2} O11.5%, so that CaO20.5%, and _Fe 2 _O 3 38.8% of the glass composition, octamethylcyclotetrasiloxane , Potassium 2-ethylhexanoate, calcium 2-ethylhexanoate mineral spirits solution (calcium content: 4.1% by mass), iron 2-ethylhexanoate mineral spirits solution (iron content: 8.0% by mass) After taking, 105 mL of mineral spirits was added as a solvent, and the mixture was stirred for 15 hours and completely dissolved to prepare a black purple liquid raw material having an oxide concentration of 5% by mass.

  A glass powder was produced from the liquid raw material in the same manner as in Example 1 using the apparatus shown in FIG.

  While observing the form of the glass powder obtained by each said Example with a transmission electron microscope (TEM, JEOL Co., Ltd. product, JEM-1230), glass transition point Tg (degreeC), glass softening point Ts ( ° C.), crystallization peak temperature Tc (° C.), average linear expansion coefficient α (50 ° C.) at 50 to 300 ° C., and the presence or absence of a crystal peak. Moreover, the TEM photograph was analyzed with image analysis software, and the average particle diameter and the average sphericity were determined. The measurement method and calculation method are shown below.

[Glass transition point Tg]
Using a differential thermal analyzer (TG8110, manufactured by Rigaku Corporation), about 20 mg of glass particles were heated from room temperature to 800 ° C. at a rate of 5 ° C./min.
[Glass softening point Ts]
About 20 mg of glass particles are placed in a platinum pan, measured at a heating rate of 10 ° C./min with a thermogravimetric / suggested thermal analyzer (TG8110, manufactured by Rigaku Corporation), and softening appears on the higher temperature side than the glass transition point Tg. The temperature at the inflection point of the DTA curve accompanying the flow was defined as the glass softening point Ts.
[Crystallization peak temperature Tc]
About 20 mg of glass particles are placed in a platinum pan and measured with a thermogravimetric / suggested thermal analyzer (TG8110 manufactured by Rigaku Corporation) at a rate of temperature increase of 10 ° C./min. The temperature of the exothermic peak of the DTA curve accompanying crystallization is determined. The crystallization peak temperature was Tc. When there was no crystallization peak or the peak was small and could not be detected, it was indicated as “−”.
[Average linear expansion coefficient α]
The sintered glass was cut to obtain a sample glass having a diameter of about 5 mmφ × 20 mm, and the sample glass was measured using a thermal dilatometer (TMA8310, manufactured by Rigaku Corporation) at a heating rate of 5 ° C./min. The sample length L ₅₀ at 50 ° C. and the sample length L 300 at 300 ° C. were measured, and the average linear expansion coefficient α at 50 ° C. to 300 ° C. was determined from the following equation.
α = {(L ₃₀₀ / L ₅₀ ) -1} / (300-50)
[Presence or absence of crystal peak]
X-ray diffraction analysis (XRD) was performed using an X-ray diffractometer (TTR-III, manufactured by Rigaku Corporation), and the presence or absence of peaks due to crystals was examined.

（ｎ：測定数（＝５０）） [Average particle size]
Using an image analysis software (WinRoof, Mitani Shoji Co., Ltd.), any 50 particles of a photograph taken with a TEM are binarized and then the diameter of an equivalent circle having the same area as the binarized area Was determined as the particle diameter (Li), and the average particle diameter (L) was calculated from the following formula.

(N: number of measurements (= 50))

（ｎ：測定数（＝５０）） [Average sphericity]
Using the image analysis software (WinRoof, Mitani Shoji Co., Ltd.), for each of the 50 particles in the photograph taken with the TEM, each particle is binarized by brightness, and then the center of gravity of the binarized figure is calculated. The maximum diameter (Dmaxi) and the minimum diameter (Dmini) that passed through were obtained, and the sphericity (Di) and the average sphericity (D) were calculated from the following equations.

(N: number of measurements (= 50))

  The measurement results are shown in Table 1 together with the glass composition. Moreover, the imaging | photography photograph with the transmission electron microscope of the glass powder of each Example is shown in FIGS. The blank in the composition column in Table 1 indicates that the content was 0%.

  As is clear from FIGS. 3 to 11, the glass powder obtained in each example is a fine glass powder with high sphericity.

  According to the method for producing glass powder of the present invention, a fine and highly spherical glass powder can be easily and stably produced. Therefore, it is useful as a method for producing a glass powder used as a material for forming a thin and homogeneous glass coating on the surface of a substrate or substrate particles.

  DESCRIPTION OF SYMBOLS 1 ... Reaction cylinder, 2 ... Burner, 3 ... Bag filter, 4 ... Glass powder collection | recovery apparatus, 5 ... Cooling pipe.

Claims (9)

A step of completely dissolving a glass raw material compound containing a plurality of glass constituent elements in a solvent, and preparing a liquid raw material in which the concentration of the glass raw material compound is 2 to 20% by mass as a total amount of oxide equivalents;
The liquid raw material with a flame or hot air, is ejected into the reaction space, after pyrolysis, a step of quenching
The manufacturing method of the glass powder characterized by including .   The method for producing glass powder according to claim 1, wherein the temperature of the flame or hot air is 1500 ° C. or higher.   The method for producing glass powder according to claim 1 or 2, wherein the liquid raw material and the flame or hot air are ejected from a common burner into the reaction space.   The said liquid raw material is a manufacturing method of the glass powder of any one of Claims 1-3 which are further ejected to the said reaction space with oxidizing gas.   The method for producing glass powder according to claim 4, wherein the liquid raw material, the flame or hot air, and the oxidizing gas are ejected from a common burner into the reaction space.   The manufacturing method of the glass powder of any one of Claims 1-5 in which the cooling means is provided around the said reaction space.   The said solvent contains the at least 1 sort (s) selected from the group which consists of water, alcohol, carboxylic acid, and a hydrocarbon, The manufacturing method of the glass powder of any one of Claims 1-6.   The average particle diameter of the said glass powder is 500 nm or less, The manufacturing method of the glass powder of any one of Claims 1-7.   The method for producing a glass powder according to any one of claims 1 to 8, wherein the glass powder has an average sphericity of 0.7 or more.

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