Device for producing microparticles and method for producing microparticles

Abstract

The present invention provides a device for manufacturing microparticles and a method for manufacturing microparticles, which can easily obtain surface-treated microparticles. The device for manufacturing microparticles uses raw materials and manufactures microparticles by a gas phase method. The device for manufacturing microparticles comprises: a processing section that uses a gas phase method to make the raw materials into a mixture in a gas phase state; a raw material supply section that supplies the raw materials to the processing section; a cooling section that uses a quenching gas containing an inert gas to cool the mixture in the gas phase state of the processing section; and a supply section that cools the mixture in the gas phase state by the quenching gas to manufacture microparticles, and supplies a surface treatment agent to the microparticles in a temperature region where the surface treatment agent does not denature.

Description

Technical Field

[0001] The present invention relates to a manufacturing device and a manufacturing method for microparticles with a particle size of 10 to 200 nm, and in particular to a manufacturing device and a manufacturing method for microparticles after surface treatment. Background Art

[0002] Currently, various microparticles are used for various purposes. For example, metal microparticles, oxide microparticles, nitride microparticles, and carbide microparticles are used in electrical insulation materials such as various electrical insulation parts, cutting tools, machine working materials, functional materials such as sensors, sintered materials, and electrode materials and catalysts for fuel cells.

[0003] In addition, in order to suppress oxidation of the various fine particles described above or to impart functions to the fine particles, a coating is formed on the surface of the fine particles.

[0004] For example, Patent Document 1 discloses titanium metal fine particles whose surfaces are coated with a compound of an organic acid and titanium and a method for producing the same.

[0005] Patent document 1 produces metal microparticles by electrically heating a metal wire having a diameter of 0.05 to 1.0 mm and composed of a metal containing 81 to 100 mol % of titanium for 0.1 to 100 microseconds in a gas environment containing vapor or mist of a carboxylic acid having 1 to 18 carbon atoms, applying energy 1.5 to 5.0 times the heat of vaporization of the metal wire.

[0006] Patent Document 2 describes a coated copper particle and a method for producing the same. The coated copper particle comprises a copper particle and a coating layer containing an aliphatic carboxylic acid. The aliphatic carboxylic acid is present in an amount of 1 nm 2 The molecular density is 2.5 or more and 5.2 or less, and is arranged on the surface of the copper particle.

[0007] In Patent Document 2, copper ions are reduced by thermally decomposing an aliphatic carboxylic acid copper complex to generate metallic copper particles. Next, an aliphatic carboxylic acid is adsorbed on the surface of the generated metallic copper particles, for example, by physical adsorption, to form a coating layer containing the aliphatic carboxylic acid at a predetermined coating density, thereby obtaining desired coated copper particles.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2010-209417

[0011] Patent Document 2: International Publication No. 2016 / 052275 Summary of the invention

[0012] Technical problem to be solved by the invention

[0013] As described above, in the method for producing titanium metal microparticles of Patent Document 1, it is necessary to heat the metal wire by electricity for 0.1 to 100 microseconds in a gas environment containing vapor or mist of a carboxylic acid having 1 to 18 carbon atoms. In the method for producing coated copper particles of Patent Document 2, it is necessary to thermally decompose an aliphatic carboxylate copper complex. In Patent Documents 1 and 2, in order to produce microparticles having a coating on the surface, heating is required, etc., which requires a lot of energy and the device will also be large-scale. In addition, the manufacturing steps will also become complicated. Under the current circumstances, it is not easy to obtain surface-treated microparticles such as microparticles having a coating on the surface in this way.

[0014] An object of the present invention is to provide a device for producing microparticles and a method for producing microparticles, which can easily obtain surface-treated microparticles.

[0015] Means for solving technical problems

[0016] In order to achieve the above-mentioned purpose, the present invention provides a manufacturing device for microparticles, which is a manufacturing device that uses raw materials and manufactures microparticles by a gas phase method, and has: a processing section that uses the gas phase method to make the raw materials into a mixture in a gas phase state; a raw material supply section that supplies the raw materials to the processing section; a cooling section that uses a quenching gas containing an inert gas to cool the gas phase mixture in the processing section; and a supply section that cools the gas phase mixture by the quenching gas to produce microparticles, and supplies a surface treatment agent to the microparticles in a temperature region where the surface treatment agent will not denature.

[0017] The gas phase method is preferably a thermal plasma method or a flame method.

[0018] The surface treatment agent is, for example, an organic acid monomer and an organic acid solution, an amine-valued dispersant monomer and an amine-valued dispersant solution, an acid-valued dispersant monomer and an acid-valued dispersant solution, an amine-valued and acid-valued dispersant monomer and an amine-valued and acid-valued dispersant solution, a silane coupling agent monomer and a silane coupling agent solution, an organic solvent, an acidic substance monomer and an acidic substance solution, an alkaline substance monomer and an alkaline substance solution, a natural resin monomer and a natural resin solution, and a synthetic resin monomer and a synthetic resin solution. In addition, the raw material is, for example, copper powder.

[0019] Preferably, the raw material supply unit supplies the raw material to the processing unit in a state of being dispersed in particles. Also, preferably, the raw material supply unit disperses the raw material in a liquid to form a slurry, and then forms droplets of the slurry and supplies the droplets to the processing unit.

[0020] The present invention provides a method for manufacturing microparticles, which is a method for manufacturing microparticles using raw materials and through a gas phase method, and comprises: using the gas phase method to make the raw materials into a mixture in a gas phase state, using a quenching gas containing an inert gas to cool the gas phase mixture to produce microparticles; and supplying a surface treatment agent to the microparticles in a temperature range where the surface treatment agent will not denature.

[0021] The gas phase method is preferably a thermal plasma method or a flame method.

[0022] For example, the surface treatment agent is an organic acid monomer and an organic acid solution, an amine-valued dispersant monomer and an amine-valued dispersant solution, an acid-valued dispersant monomer and an acid-valued dispersant solution, an amine-valued and acid-valued dispersant monomer and an amine-valued and acid-valued dispersant solution, a silane coupling agent monomer and a silane coupling agent solution, an organic solvent, an acidic substance monomer and an acidic substance solution, an alkaline substance monomer and an alkaline substance solution, a natural resin monomer and a natural resin solution, and a synthetic resin monomer and a synthetic resin solution. In addition, the raw material is, for example, copper powder.

[0023] In the step of manufacturing the microparticle, it is preferred that the raw materials are made into a mixture in a gas phase using a thermal plasma flame, and the raw materials are supplied to the thermal plasma flame in a dispersed particle state. In addition, in the step of manufacturing the microparticle, it is preferred that the raw materials are made into a mixture in a gas phase using a thermal plasma flame, and the raw materials are dispersed in a liquid to form a slurry, and the slurry is dropletized and supplied to the thermal plasma flame.

[0024] Effects of the Invention

[0025] According to the apparatus and method for producing fine particles of the present invention, surface-treated fine particles can be easily obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram showing an example of a microparticle production apparatus used in the method for producing microparticles of the present invention.

[0027] Figure 2 This is a schematic diagram showing an example of fine particles obtained by the method for producing fine particles of the present invention.

[0028] Figure 3 This is a graph showing the removal rate of the surface coating of the fine particles obtained by the method for producing fine particles of the present invention.

[0029] Reference numerals

[0030] 10 microparticle manufacturing device 12 plasma torch 14 material supply device 15 primary microparticles 16 chamber

[0031] 18 secondary particles 19 cyclone separator 20 recovery unit 22 plasma gas supply source

[0032] 22a first gas supply unit 22b second gas supply unit 24 thermal plasma flame 28 gas supply device

[0033] 28a First gas supply source 28b Second gas supply source 29 Vacuum pump

[0034] 30 surface treated particles (particles) 40 supply unit 42 sensor St surface treatment agent DETAILED DESCRIPTION

[0035] Hereinafter, the microparticle production device and the microparticle production method of the present invention will be described in detail based on the preferred embodiments shown in the drawings.

[0036] The following is an example of the manufacturing device and method of the microparticles of the present invention, but the present invention is not limited to the present invention. Figure 1 The manufacturing device and manufacturing method shown.

[0037] Figure 1 This is a schematic diagram showing an example of a microparticle production apparatus used in the method for producing microparticles of the present invention. Figure 1 The microparticle production apparatus 10 (hereinafter referred to as the production apparatus 10) shown is an apparatus used for producing the surface-treated microparticles 30. The production apparatus 10 can easily obtain the surface-treated microparticles 30.

[0038] The type of the surface-treated fine particles 30 manufactured by the manufacturing device 10 is not particularly limited. The manufacturing device 10 can supply a surface treatment agent to various fine particles such as metal fine particles, oxide fine particles, nitride fine particles, carbide fine particles, and oxynitride fine particles obtained by changing the composition of the raw material, thereby manufacturing the surface-treated fine particles 30. The surface-treated fine particles 30 are also referred to as fine particles 30 in the following.

[0039] The manufacturing device 10 has: a plasma torch 12 that generates a hot plasma flame; a material supply device 14 that supplies a raw material powder of fine particles into the plasma torch 12; a chamber 16 that functions as a cooling tank for generating primary fine particles 15; a cyclone separator 19 that removes coarse particles having a particle size greater than an arbitrary predetermined particle size from the primary fine particles 15; and a recovery unit 20 that recovers the secondary fine particles 18 that have been classified by the cyclone separator 19 and have a desired particle size. The manufacturing device 10 further has: a supply unit 40 that supplies a surface treatment agent to the secondary fine particles 18; and a sensor 42 that measures the temperature of the secondary fine particles 18 conveying passage.

[0040] The primary particles 15 and the secondary particles 18 are both particles in the process of manufacturing the particles of the present invention. The particles obtained by surface treating the secondary particles 18, that is, the surface treated particles 30, are the particles of the present invention.

[0041] As the material supply device 14 , the chamber 16 , the cyclone separator 19 , and the recovery unit 20 , for example, various devices disclosed in Japanese Patent Application Laid-Open No. 2007-138287 may be used.

[0042] In the present embodiment, when producing fine particles, for example, copper powder can be used as a raw material. In this case, the fine particles 30, primary fine particles 15, and secondary fine particles 18 finally obtained are composed of copper.

[0043] The average particle size of the copper powder can be appropriately set so that it can be easily evaporated in the hot plasma flame. The average particle size of the copper powder is measured using a laser diffraction method, for example, 100 μm or less, preferably 10 μm or less, and more preferably 5 μm or less. In addition, the raw material is not limited to copper, and powders of metals other than copper can also be used, and even alloy powders can be used.

[0044] The plasma torch 12 is composed of a quartz tube 12a and a high-frequency vibration coil 12b wound around the outside thereof. At the upper part of the plasma torch 12, a supply pipe 14a described later is provided in the central part thereof for supplying raw material powder of microparticles into the plasma torch 12. A plasma gas supply port 12c is formed at the peripheral part (on the same circumference) of the supply pipe 14a, and the plasma gas supply port 12c is annular. A power supply (not shown) for generating a high-frequency voltage is connected to the high-frequency vibration coil 12b. If a high-frequency voltage is applied to the high-frequency vibration coil 12b, a hot plasma flame 24 will be generated. Through the hot plasma flame 24, the raw material (not shown) will evaporate and become a mixture in a gas phase state. The plasma torch 12 is a buried part for making the raw material into a mixture in a gas phase state using the gas phase method of the present invention.

[0045] The plasma gas supply source 22 is a device for supplying plasma gas into the plasma torch 12, and for example, has a first gas supply unit 22a and a second gas supply unit 22b. The first gas supply unit 22a and the second gas supply unit 22b are connected to the plasma gas supply port 12c via a pipe 22c. Although not shown in the figure, a supply amount adjustment unit such as a valve for adjusting the supply amount is provided in the first gas supply unit 22a and the second gas supply unit 22b, respectively. The plasma gas is supplied from the plasma gas supply source 22 through the annular plasma gas supply port 12c to the plasma torch 12 from the direction indicated by the arrow P and the direction indicated by the arrow S.

[0046] The plasma gas may be a mixed gas of hydrogen and argon, for example. In this case, the first gas supply unit 22a stores hydrogen, and the second gas supply unit 22b stores argon. Hydrogen is supplied from the first gas supply unit 22a of the plasma gas supply source 22, and argon is supplied from the second gas supply unit 22b through the pipe 22c, through the plasma gas supply port 12c, and from the direction indicated by the arrow P and the direction indicated by the arrow S to the plasma torch 12. Alternatively, only argon may be supplied from the direction indicated by the arrow P.

[0047] In addition, the plasma gas can be used according to the fine particles to be produced, and therefore, it is not necessary to use a mixed gas as described above, and the plasma gas may be a single type of gas.

[0048] When a high-frequency voltage is applied to the high-frequency vibration coil 12 b , a hot plasma flame 24 is generated in the plasma torch 12 .

[0049] The temperature of the hot plasma flame 24 must be higher than the boiling point of the raw material powder. On the other hand, the higher the temperature of the hot plasma flame 24, the easier it is for the raw material powder to be in a gas phase, so it is preferred, and the temperature is not particularly limited. For example, the temperature of the hot plasma flame 24 can be set to 6000°C, and it is theoretically believed that it will reach about 10000°C.

[0050] In addition, the gas atmosphere pressure in the plasma torch 12 is preferably below the atmospheric pressure. Here, the gas atmosphere below the atmospheric pressure is, for example, 0.5 to 100 kPa, but is not particularly limited.

[0051] In addition, the outer side of the quartz tube 12a is surrounded by a tube (not shown) formed in a concentric circle shape, and cooling water circulates between the tube and the quartz tube 12a to water-cool the quartz tube 12a to prevent the quartz tube 12a from becoming too hot due to the hot plasma flame 24 generated in the plasma torch 12.

[0052] The material supply device 14 is connected to the upper part of the plasma torch 12 via a supply pipe 14a. The material supply device 14 is a device that supplies a raw material to the hot plasma flame 24 in the plasma torch 12. The material supply device 14 is a raw material supply part of the present invention.

[0053] The material supply device 14 is not particularly limited as long as it can supply the raw material to the hot plasma flame 24. For example, two methods can be used: supplying the raw material to the hot plasma flame 24 in a dispersed particle state, and making the raw material into a slurry and supplying the slurry to the hot plasma flame 24 in the form of droplets.

[0054] When the raw material is a powder, for example, copper powder is supplied in the form of a powder. As described above, the material supply device 14 disclosed in Japanese Patent Application Laid-Open No. 2007-138287 can be used. In this case, the material supply device 14 includes, for example: a storage tank (not shown) for storing the raw material; a screw feeder (not shown) for quantitatively conveying the raw material; a dispersion unit (not shown) for dispersing the raw material conveyed by the screw feeder in the form of primary particles before it is finally dispersed; and a carrier gas supply source (not shown).

[0055] The raw material is supplied to the hot plasma flame 24 in the plasma torch 12 through the supply pipe 14 a together with the carrier gas extruded and pressurized from the carrier gas supply source.

[0056] The material supply device 14 is not particularly limited in configuration as long as it can prevent the agglomeration of the raw material and disperse the raw material in the plasma torch 12 while maintaining a dispersed state. The carrier gas can use an inert gas such as argon. The flow rate of the carrier gas can be controlled using a flow meter such as a float flow meter. In addition, the flow rate value of the carrier gas refers to the scale value of the flow meter.

[0057] The material supply device 14 that supplies the raw material in the form of slurry can use, for example, the device disclosed in Japanese Patent Publication No. 2011-213524. In this case, the material supply device 14 has: a container (not shown) containing a slurry (not shown) in which the powdered raw material is dispersed in a liquid such as water; a stirrer (not shown) that stirs the slurry in the container; a pump (not shown) that applies high pressure to the slurry through the supply pipe 14a and supplies it to the plasma torch 12; and a spray gas supply source (not shown) that supplies a spray gas for dropletizing the slurry and supplying it to the plasma torch 12. The spray gas supply source is equivalent to a carrier gas supply source. The spray gas is also called a carrier gas.

[0058] When the raw material is supplied in the form of slurry, the powdered raw material is dispersed in a liquid such as water to prepare the slurry. The mixing ratio of the powdered raw material and water in the slurry is not particularly limited, and is, for example, 5:5 (50%:50%) by mass.

[0059] When a material supply device 14 is used that converts a powdered raw material into a slurry and supplies the slurry in the form of droplets, the spray gas extruded from the spray gas supply source and pressurized is supplied to the hot plasma flame 24 in the plasma flame 12 through the supply pipe 14a together with the slurry. The supply pipe 14a has a two-fluid nozzle mechanism for spraying the slurry into the hot plasma flame 24 in the plasma torch and dropletizing it, thereby spraying the slurry into the hot plasma flame 24 in the plasma torch 12. That is, the slurry can be dropletized. The spray gas, like the above-mentioned carrier gas, can use an inert gas such as argon (Ar gas) and nitrogen.

[0060] In this way, the two-fluid nozzle mechanism can apply high pressure to the slurry and spray the slurry through the spray gas (carrier gas), which is one of the methods used to dropletize the slurry.

[0061] In addition, the present invention is not limited to the above-mentioned two-fluid nozzle mechanism, and a single-fluid nozzle mechanism may also be used. In addition, other methods include, for example, a method of dropping the slurry on a rotating circular plate at a certain speed and dropletizing (forming droplets) by centrifugal force, and a method of dropletizing (generating droplets) by applying a high voltage to the slurry surface. For example, the raw material slurry is an alcohol slurry of titanium oxide.

[0062] The chamber 16 is provided adjacent to the lower side of the plasma torch 12 and is connected to a gas supply device 28. Primary particles 15 of, for example, copper are generated in the chamber 16. The chamber 16 also functions as a cooling tank.

[0063] The gas supply device 28 supplies cooling gas (quenching gas) containing an inert gas into the chamber 16. The raw material is evaporated by the thermal plasma flame 24 to form a mixture in a gas phase, and the gas supply device 28 supplies cooling gas (quenching gas) containing an inert gas to the mixture.

[0064] The gas supply device 28 includes, for example, a first gas supply source 28a, a second gas supply source 28b, and a pipe 28c. The gas supply device 28 further includes a pressure imparting device (not shown) such as a compressor or a blower that squeezes out and applies pressure to the cooling gas supplied into the chamber 16. The gas supply device 28 is a cooling unit of the present invention.

[0065] In addition, a pressure control valve 28d for controlling the gas supply amount from the first gas supply source 28a is provided, and a pressure control valve 28e for controlling the gas supply amount from the second gas supply source 28b is provided. For example, argon gas is stored in the first gas supply source 28a. In this case, the cooling gas is argon gas. In addition, a gas different from that of the first gas supply source 28a can be stored in the second gas supply source 28b. In this case, a mixed gas of the gas stored in the first gas supply source 28a and the gas stored in the second gas supply source 28b is a cooling gas (quenching gas). For example, if methane gas is stored in the second gas supply source 28b, the cooling gas (quenching gas) is a mixed gas of argon gas and methane gas.

[0066] The gas supply device 28 supplies argon gas as cooling gas in the direction of arrow Q at an angle of, for example, 45° toward the tail of the hot plasma flame 24, that is, one end of the hot plasma flame 24 on the opposite side of the plasma gas supply port 12c, that is, the terminal end of the hot plasma flame 24, and supplies argon gas as cooling gas in the direction of arrow Q along the inner wall 16a of the chamber 16 from top to bottom, that is, toward Figure 1 The cooling gas is supplied in the direction of arrow R shown.

[0067] The copper powder that is evaporated by the hot plasma flame 24 and becomes a mixture in a gas phase is rapidly cooled by the cooling gas supplied from the gas supply device 28 into the chamber 16, and the primary copper particles 15 can be obtained. In addition, the cooling gas has an additional function of helping to classify the primary particles 15 in the cyclone separator 19. The cooling gas is, for example, argon gas.

[0068] When the primary copper particles 15 are first generated, if the particles collide with each other and form aggregates, uneven particle sizes will occur, which will lead to quality reduction. However, argon gas as a cooling gas supplied in the direction of arrow Q toward the tail (terminal end) of the thermal plasma flame will dilute the primary particles 15 and prevent the particles from colliding with each other and agglomerating.

[0069] Furthermore, by supplying argon gas as cooling gas in the direction of arrow R, the primary particles 15 can be prevented from adhering to the inner wall 16 a of the chamber 16 during the recovery process of the primary particles 15 , thereby improving the yield of the generated primary particles 15 .

[0070] Although argon gas is used as the cooling gas (quenching gas), it is not limited thereto, and an inert gas other than argon gas may be used, such as nitrogen gas, etc. The cooling gas is not limited to an inert gas, and air, oxygen, or carbon dioxide may be used.

[0071] In addition, the cooling gas (quenching gas) can also use a hydrocarbon gas with a carbon number of 4 or less, in addition to the above-mentioned argon gas, for example. Therefore, the cooling gas (quenching gas) can use methane (CH4), ethane (C2H6), propane (C3H8) and butane (C4H 10 ) and other paraffin hydrocarbon gases, as well as olefin hydrocarbon gases such as ethylene (C2H4), propylene (C3H6) and butene (C4H8).

[0072] like Figure 1 As shown in FIG. 1 , a cyclone separator 19 for classifying primary particles 15 of copper into desired particle sizes is provided in the chamber 16. The cyclone separator 19 comprises: an inlet pipe 19a for supplying primary particles 15 from the chamber 16; a cylindrical outer cylinder 19b connected to the inlet pipe 19a and located at the upper part of the cyclone separator 19; a truncated cone portion 19c which is continuous from the lower part of the outer cylinder 19b to the lower side and whose diameter gradually decreases; a coarse particle recovery chamber 19d connected to the lower side of the truncated cone portion 19c and recovers coarse particles having a particle size larger than the above-mentioned desired particle size; and an inner tube 19e connected to a recovery unit 20 described in detail later and protruding from the outer cylinder 19b. The chamber 16 and the inlet pipe 19a are connected to each other by a connecting pipe 21, and the primary particles 15 are moved to the cyclone separator 19 through the connecting pipe 21. The connecting pipe 21 is a conveying passage for the primary particles 15.

[0073] The air flow containing the primary particles 15 is blown from the inlet pipe 19a of the cyclone separator 19 along the inner peripheral wall of the outer cylinder 19b, whereby the air flow is as follows: Figure 1 As shown by the middle arrow T, the liquid flows from the inner peripheral wall of the outer cylinder 19b toward the truncated cone portion 19c, forming a descending swirling flow.

[0074] Then, when the descending swirling flow is reversed to become an ascending airflow, the coarse particles cannot rise with the ascending airflow due to the balance between the centrifugal force and the resistance force, and they fall along the side of the truncated cone portion 19c and are recovered in the coarse particle recovery chamber 19d. In addition, the microparticles that are more affected by the resistance force than the centrifugal force are discharged from the inner tube 19e to the outside of the cyclone separator 19 together with the ascending airflow on the inner wall of the truncated cone portion 19c.

[0075] In addition, negative pressure (attractive force) is generated from the recovery unit 20 described in detail later through the inner tube 19e. Then, the microparticles separated from the swirling airflow are attracted as shown by the symbol U and sent to the recovery unit 20 through the inner tube 19e.

[0076] A recovery unit 20 for recovering microparticles 30 having a desired nanometer-level particle size is provided on an extension line of the inner tube 19e of the airflow outlet in the cyclone separator 19. The recovery unit 20 comprises: a recovery chamber 20a; a filter 20b provided in the recovery chamber 20a; and a vacuum pump 29 connected via a pipe provided at the bottom of the recovery chamber 20a. The microparticles 30 sent out from the cyclone separator 19 are sucked into the recovery chamber 20a by the vacuum pump 29, and are recovered in a state of staying on the surface of the filter 20b.

[0077] Furthermore, in the above-mentioned production apparatus 10, the number of cyclone separators used is not limited to one, and may be two or more.

[0078] The supply unit 40 is a device for supplying the surface treatment agent St to the microparticle body (secondary microparticles 18) in a temperature range where the surface treatment agent St does not denature. Figure 1 As shown, the supply unit 40 is provided near the recovery unit 20 of the inner tube 19e. The supply unit 40 supplies the surface treatment agent St to the secondary microparticles 18 passing through the inner tube 19e. Thereby, the surface treatment agent St is attached to the secondary microparticles 18, and the secondary microparticles 18 are surface treated to obtain microparticles 30 having properties based on the surface treatment agent St.

[0079] The method of supplying the surface treatment agent St by the supply unit 40 is not particularly limited, and an example thereof is a method of converting the surface treatment agent St into droplets and spraying the droplets onto the secondary fine particles 18 .

[0080] As described above, the surface treatment agent St is supplied in a temperature range where the surface treatment agent St does not denature. In the temperature range where the surface treatment agent St does not denature, the surface treatment agent St does not decompose due to heat or the like, and the properties of the surface treatment agent St do not change. Therefore, the properties of the surface treatment agent St can be maintained in the microparticles 30, and the microparticles 30 have properties based on the surface treatment agent St.

[0081] The temperature range in which the surface treatment agent St does not denature is a temperature range determined based on the temperature measured by differential thermal-thermogravimetric simultaneous measurement (TG-DTA).

[0082] The temperature range in which the surface treatment agent St does not denature is set to a temperature range in which the weight reduction ratio is 50% by mass or less in the differential thermal-thermogravimetric simultaneous measurement of the surface treatment agent St. The weight reduction ratio is preferably 30% by mass or less, and more preferably 10% by mass or less.

[0083] It is preferred that the surface treatment agent St is as invariant as possible. If the weight loss ratio measured by the differential thermal-thermogravimetric simultaneous measurement exceeds 50% by mass, the influence of the denaturation of the surface treatment agent may become non-negligible. In order to eliminate the influence of the denaturation of the surface treatment agent, the weight loss ratio is preferably 30% by mass or less, more preferably 10% by mass or less, as described above.

[0084] For the simultaneous differential thermal and thermogravimetric measurement, STA7200 (trade name) manufactured by Hitachi High Tech Science Co., Ltd. can be used.

[0085] The surface treatment agent St is not particularly limited, and examples thereof include organic acid monomers and organic acid solutions, dispersant monomers with amine value and dispersant solutions with amine value, dispersant monomers with acid value and dispersant solutions with acid value, dispersant monomers with amine value and acid value and dispersant solutions with amine value and acid value, silane coupling agent monomers and silane coupling agent solutions, organic solvents, acidic substance monomers and acidic substance solutions, and alkaline substance monomers and alkaline substance solutions. In addition to the above, the surface treatment agent St may also include natural resin monomers and natural resin solutions, and synthetic resin monomers and synthetic resin solutions.

[0086] In addition, as long as the use state of the organic acid is liquid, it is not necessary to dissolve the organic acid in the solvent like the aqueous solution, and the organic acid can also be used as a monomer. When using the surface treatment agent St of an acidic substance, an alkaline substance, a natural resin, a synthetic resin, etc. other than the organic acid, it is also similar to the organic acid, as long as the use state is liquid, it can be used as a monomer.

[0087] (Dispersant monomer and dispersant solution)

[0088] The dispersant may be, for example, a dispersant having only an amine value, a dispersant having only an acid value, or a dispersant having both an amine value and an acid value. The following products may be used as the dispersant. When the dispersant has an amine value, the amine value of the dispersant is preferably 10 to 100, more preferably 10 to 60.

[0089] Examples of dispersants having only amine values ​​include DISPERBYK-102, DISPERBYK-160, DISPERBYK-161, DISPERBYK-162, DISPERBYK-2163, DISPERBYK-2164, DISPERBYK-166, and DISPERBYK-1. 67. DISPERBYK-168, DISPERBYK-2000, DISPERBYK-2050, DISPERBYK-2150, DISPERBYK-2155, DISPERBYK-LPN6919, DISPERBYK-LPN21116, DISPERBYK-LPN 21234, DISPERBYK-9075, DISPERBYK-9077 (all manufactured by BYK-Chemie); EFKA4015, EFKA4020, EFKA4046, EFKA4047, EFKA4050, EFKA4055, EFKA4060, EFKA4080, EFKA4300, EFKA4330, EFKA4340, EFKA4400, EFKA4401, EFKA4402, EFKA4403, EFKA4800 (all manufactured by BASF); AJISPER (registered trademark) PB711 (manufactured by Fine-Techno Co., Ltd.), etc.

[0090] Examples of polymer dispersants having an amine value and an acid value include DISPERBYK-142, DISPERBYK-145, DISPERBYK-2001, DISPERBYK-2010, DISPERBYK-2020, DISPERBYK-2025, DISPERBYK-9076, and Anti-Terra-205 (all manufactured by BYK-Chemie); SOLSPERSE 24000 (manufactured by Lubrizol Corporation); AJISPER (registered trademark) PB821, AJISPER PPB880, and AJISPER PPB881 (all manufactured by Ajisper Fine-Techno Co., Ltd.); and the like.

[0091] Dispersants having only an acid value, such as DISPERBYK-110, DISPERBYK-111, DISPERBYK-170, DISPERBYK-171, DISPERBYK-174 (all manufactured by BYK-Chemie), BYK-P104, BYK-P104S, BYK-P105, BYK-220S (all manufactured by BYK-Chemie), EFKA5010, EFKA5065, EFKA5066, EFKA5070 (all manufactured by BASF), SOLSPERSE3000, SOLSPERSE16 000, SOLSPERSE 17000, SOLSPERSE 18000, SOLSPERSE 21000, SOLSPERSE 27000, SOLSPERSE 28000, SOLSPERSE 36000, SOLSPERSE 36600, SOLSPERSE 38500, SOLSPERSE 39000, SOLSPERSE 41000 (all manufactured by Lubrizol), AJISPER (registered trademark) PN-411, AJISPERPA-111 (manufactured by Ajisper Fine-Techno Co., Ltd.), etc.

[0092] (Silane coupling agent monomer and silane coupling agent solution)

[0093] The silane coupling agent may be a compound represented by the following formula. In the following formula, X is an organic reactive group, and may be an amino group, an epoxy group, a mercapto group, a methacryl group, a vinyl group, etc. Y is an inorganic reactive group, which is a reactive group (alkoxy) represented by the general formula (-OR), and R is the same or different saturated alkyl group having 1 to 3 carbon atoms. In addition, n is an integer of 1 to 3.

[0094] [Chemistry 1]

[0095]

[0096] Specifically, examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, vinyl-tri(2-methoxyethoxy)silane, vinyltrichlorosilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and bis(3-triethoxysilylpropyl)tetrasulfide.

[0097] The silane coupling agent solution is, for example, a solution containing the above-mentioned silane coupling agent. The content of the silane coupling agent in the solution is not particularly limited and can be appropriately determined according to the application and the like.

[0098] (Organic Solvent)

[0099] The organic solvent is not particularly limited and can be appropriately selected according to the purpose. Examples of the organic solvent include alcohols such as methanol, ketones such as acetone, amides such as halogenated hydrocarbons, amides such as formamide, sulfoxides such as dimethyl sulfoxide, heterocyclic compounds, hydrocarbons, esters such as ethyl acetate, and ethers. These can be used alone or in combination of two or more.

[0100] (Acidic substance monomer and acidic substance solution)

[0101] Examples of the acidic substance include acids such as hydrochloric acid, nitric acid, formic acid, acetic acid, and sulfuric acid.

[0102] The acidic substance solution is, for example, a solution containing the above-mentioned acidic substance. The content of the acidic substance in the solution is not particularly limited and can be appropriately determined according to the application and the like.

[0103] (Alkaline substance monomer and alkaline substance solution)

[0104] Alkaline substances include amines such as ammonia, monoethanolamine, diethanolamine, triethanolamine, methylamine, dimethylamine, ethylamine, diethylamine, trimethylamine, triethylamine, guanidine, picoline, aniline, pyridine, piperidine, morpholine, N-methylaniline, toluidine, and N,N-dimethyl-p-toluidine; alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; and metal alkoxides such as sodium methoxide, sodium ethoxide, and sodium butoxide. Among these, amines such as ammonia and monoethanolamine, which are weakly alkaline substances, are preferred, and monoethanolamine is most preferred.

[0105] (Organic acid monomer and organic acid solution)

[0106] When an organic acid of an acidic substance is used as the surface treatment agent, an aqueous solution is prepared using pure water as a solvent, for example, and the aqueous solution is sprayed from the supply unit 40. In this case, the organic acid is preferably water-soluble and has a low boiling point, and the organic acid is preferably composed of only C, O, and H. Examples of the organic acid that can be used include L-ascorbic acid (C6H8O6), formic acid (CH2O2), glutaric acid (C5H8O4), succinic acid (C4H6O4), oxalic acid (C2H2O4), DL-tartaric acid (C4H6O6), lactose monohydrate, maltose monohydrate, maleic acid (C4H4O4), D-mannitol (C6H 14 O6), citric acid (C6H8O7), malic acid (C4H6O5), malonic acid (C3H4O4) and aliphatic carboxylic acids, etc. It is preferred to use at least one of the above organic acids.

[0107] Argon gas, for example, can be used as the spray gas for dropletizing the aqueous solution of the organic acid. However, the gas is not limited to argon gas, and an inert gas such as nitrogen gas may also be used.

[0108] (Natural resin monomer and natural resin solution)

[0109] Natural resins include rosin, shellac, copal, dammar resin, frankincense, dragon's blood resin, styrax, copaiba balsam, elemi resin, frankincense, myrrh and red myrrh, etc.

[0110] (Synthetic resin monomer and synthetic resin solution)

[0111] Synthetic resins include phenol resin, urea resin, melamine resin, unsaturated polyester resin, polyurethane, diallyl phthalate resin, silicone resin, alkyd resin, epoxy resin, polyethylene, polypropylene, polystyrene, acrylonitrile styrene resin, acrylonitrile butadiene styrene resin, polyvinyl chloride, methacrylic resin, polyethylene terephthalate, polyamide, polyacetal, polycarbonate, modified polyphenylene ether, polybutylene terephthalate, polyphenylene sulfide, polyimide, polyetherimide, polyarylate, polysulfone, polyether alkali, polyether ether ketone, polytetrafluoroethylene, fluororesin, polymethyl terpene, isoprene rubber, butadiene rubber, chloroprene rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, butyl rubber, urethane rubber, silicone rubber and acrylic rubber.

[0112] The sensor 42 is a device for measuring the temperature of the conveying path of the secondary fine particles 18. The temperature measurement result can be used to determine whether it is a temperature range in which the surface treatment agent St does not denature.

[0113] In this case, the temperature measurement result is transmitted to, for example, the supply unit 40. In the supply unit 40, it is possible to determine whether the temperature is in the temperature range where the surface treatment agent St does not denature, based on the temperature measurement result of the secondary particle 18 conveying passage obtained by the sensor 42. When the temperature of the secondary particle 18 conveying passage is in the temperature range where the surface treatment agent St denatures, for example, the manufacturing conditions of the primary particles 15 in the manufacturing device 10 are changed.

[0114] As described above, the temperature measurement result of the sensor 42 is used to determine whether it is a temperature range where the surface treatment agent St does not denature, so the sensor 42 is preferably provided on the upstream side of the conveying direction of the secondary particles 18 and near the supply unit 40. Therefore, the sensor 42 can be provided in the inner tube 19e, for example.

[0115] The configuration of the sensor 42 is not particularly limited as long as it can measure temperature, but a short measuring time is preferred. Therefore, the sensor 42 may be, for example, a resistance thermometer, a radiation thermometer, an infrared radiation temperature sensor, or a thermistor.

[0116] Next, an example of a method for producing fine particles using the above-described production apparatus 10 will be described.

[0117] First, a raw material powder of fine particles, for example, copper powder having an average particle size of 5 μm or less, is fed into the material supply device 14 .

[0118] Argon gas and hydrogen gas, for example, are used as the plasma gas, and a high-frequency voltage is applied to the high-frequency vibration coil 12 b to generate a hot plasma flame 24 in the plasma torch 12 .

[0119] In addition, argon gas, for example, is supplied as cooling gas from the gas supply device 28 to the tail of the thermal plasma flame 24, that is, the terminal end of the thermal plasma flame 24, in the direction of arrow Q. At this time, argon gas is supplied in the direction of arrow R as cooling gas.

[0120] Next, copper powder is gaseously transported using, for example, argon as a carrier gas and supplied to the hot plasma flame 24 in the plasma torch 12 through the supply pipe 14a. The supplied copper powder evaporates into a gas phase in the hot plasma flame 24 and is rapidly cooled by the cooling gas to generate primary copper particles 15.

[0121] The primary copper particles 15 obtained in the chamber 16 are blown from the inlet pipe 19a of the cyclone separator 19 along the inner peripheral wall of the outer cylinder 19b together with the air flow through the connecting pipe 21, thereby Figure 1 As shown by the arrow T, the particles flow along the inner wall of the outer cylinder 19b, forming a swirling flow and descending. Then, when the descending swirling flow is reversed to become an ascending airflow, the coarse particles cannot rise with the ascending airflow due to the balance between the centrifugal force and the resistance force, and they descend along the side of the truncated cone 19c and are recovered in the coarse particle recovery chamber 19d. In addition, the microparticles that are more affected by the resistance force than the centrifugal force are discharged from the inner wall of the truncated cone 19c together with the ascending airflow on the inner wall of the truncated cone 19c to the outside of the cyclone separator 19.

[0122] The discharged secondary particles 18 are moved to the recovery unit 20 by the negative pressure (suction force) generated by the vacuum pump 29. Figure 1 The secondary particles 18 are attracted in the direction indicated by the symbol U and pass through the inner tube 19e. When the secondary particles 18 pass through the inner tube 19e, the surface treatment agent St is supplied to the secondary particles 18 from the supply unit 40 in the form of, for example, spray, and the secondary particles 18 are surface treated. The surface treated secondary particles 18, i.e., particles 30, are sent to the recovery unit 20 and are recovered through the filter 20b of the recovery unit 20. In this way, for example, Figure 2 The microparticles shown.

[0123] When the fine particles 30 are recovered in the recovery unit 20, the internal pressure in the cyclone separator 19 is preferably equal to or lower than the atmospheric pressure. The particle size of the fine particles 30 can be set to any particle size of the nanometer level according to the purpose.

[0124] In addition, in the present invention, a thermal plasma flame is used as a heat source to form primary copper particles, but other gas phase methods can also be used to form primary copper particles. Therefore, as long as it is a gas phase method, it is not limited to using a thermal plasma flame, and it can also be a manufacturing method for forming primary copper particles by, for example, a flame method. In addition, the manufacturing method of primary particles using a thermal plasma flame is called a thermal plasma method.

[0125] Here, the flame method refers to a method of synthesizing microparticles by using flame as a heat source, for example, passing a raw material containing copper through a flame. In the flame method, for example, a raw material containing copper is supplied to a flame, and then a cooling gas is supplied to the flame to reduce the temperature of the flame to suppress the growth of copper particles, thereby obtaining primary microparticles 15 of copper.

[0126] In the flame method, the same cooling gas and surface treatment agent as those in the thermal plasma method can be used.

[0127] Next, the microparticles will be described.

[0128] The particle size of the microparticles is 10 to 200 nm and is surface treated as described above. The surface treated microparticles have properties based on the properties of the surface treatment agent. Thus, for example, if the surface treatment agent is a dispersant having an amine value, the microparticles have dispersibility to acidic solvents, etc. If the surface treatment agent is an organic acid of an acidic substance, the microparticles have hydrophilicity or acidity.

[0129] Furthermore, the particle size of the microparticles is 10 to 200 nm, and the particle size of the microparticles is preferably 10 to 150 nm.

[0130] The particle size of the fine particles of the present invention is an average particle size measured using the BET method.

[0131] The microparticles of the present invention are not dispersed in a solvent, but exist independently. Therefore, when the microparticles are used in combination with a solvent, the combination of the microparticles and the solvent is not particularly limited, and the degree of freedom in selecting the solvent is high.

[0132] Furthermore, the surface state of the surface-treated fine particles can be examined using, for example, FT-IR (Fourier transform infrared spectrophotometer).

[0133] The microparticles of the present invention can be produced using the above-mentioned production apparatus 10, and the surface treatment agent is an ethanol solution of terpineol. Specifically, the production conditions of the microparticles are as follows: plasma gas: argon 200 liters / minute, hydrogen 5 liters / minute; carrier gas: argon 5 liters / minute; quenching gas: argon 150 liters / minute; internal pressure: 40 kPa.

[0134] The surface treatment agent is a secondary fine particle sprayed onto copper using a spray gas, and the spray gas is argon gas.

[0135] Here, Figure 3 Graph showing the removal rate of the surface coating of the microparticles obtained by the method for producing microparticles of the present invention. Figure 3 This is a graph obtained based on the results of differential thermal-thermogravimetric simultaneous measurement (TG-DTA) performed in an inert gas atmosphere.

[0136] Figure 3 Reference numeral 50 represents the microparticles of the present invention (copper microparticles), reference numeral 52 represents the copper microparticles of Conventional Example 1, and reference numeral 54 represents terpineol used as a surface treatment agent.

[0137] Conventional Example 1 can be produced by the same production method as the production method of the microparticles of the present invention except that methane gas is used as the quenching gas and no surface treatment agent is supplied, compared to the present invention product.

[0138] like Figure 3 As shown, the removal rate of the surface coating of the microparticles of the present invention (reference symbol 50) has the same tendency as that of terpineol (reference symbol 54) used as the surface treatment agent. On the other hand, the removal rate of the conventional example 1 (reference symbol 52) does not change until the temperature is around 400°C, showing a different tendency.

[0139] from Figure 3 The removal rate of the surface coating of the fine particles of the present invention (reference numeral 50) shown above indicates that the fine particles of the present invention adsorb terpineol as the surface treatment agent.

[0140] The improvement of dispersibility is confirmed by making a coating film with the dispersion. Generally speaking, if the affinity of the microparticles for the solvent is low, the dispersibility is deteriorated, the viscosity of the dispersion increases, and the operability of the dispersion is deteriorated. Therefore, the microparticles of the present invention are dispersed in a solvent (terpineol (C 10 H 18 The dispersion was prepared by adding 0.25 g of the microparticles to 1 g of the solvent, and the coating was also formed when 0.5 g was added.

[0141] The microparticles of the prior art example 1 are dispersed in a solvent (terpineol (C 10 H 18 The dispersion was prepared by adding 0.25 g of the microparticles of the prior art example 1 to 1 g of the solvent to form a coating film, but no coating film could be formed when 0.5 g was added.

[0142] This shows that the microparticles of the present invention have improved dispersibility in the solvent compared to the microparticles of Conventional Example 1.

[0143] In the present invention, as described above, the surface treatment agent is supplied to the secondary microparticles in a temperature region where the surface treatment agent does not denature, and surface-treated microparticles can be obtained. In the present invention, surface-treated particles can be directly obtained, so there is no need to mix, dry, and recycle the non-surface-treated particles with the surface treatment agent after manufacturing and recycling to perform surface treatment on the particles, which can simplify the manufacturing steps. In this way, in the present invention, surface-treated microparticles can be easily manufactured.

[0144] Furthermore, the properties of the fine particles can be controlled by the properties of the surface treatment agent, so fine particles suitable for the intended use can be easily produced by changing the surface treatment agent.

[0145] Regarding the use of surface-treated microparticles, for example, when making conductors such as conductive wiring, the microparticles can be mixed with copper particles with a particle size of μm to make them function as sintering aids for the copper particles. In addition, in addition to conductors such as conductive wiring, surface-treated microparticles can also be used in situations where conductivity is required, such as bonding between semiconductor elements, bonding between semiconductor elements and various electronic devices, and bonding between semiconductor elements and wiring layers.

[0146] The present invention is basically constituted as described above. The above has been described in detail with respect to the microparticle manufacturing device and microparticle manufacturing method of the present invention, but the present invention is not limited to the above-mentioned embodiments, and various improvements or changes can be made without departing from the scope of the present invention.

Claims

1. A device for producing microparticles, which uses a raw material and produces microparticles by a thermal plasma method or a flame method, characterized in that: have: A processing section for converting the raw material into a mixture in a gas phase state using the thermal plasma method or the flame method; a raw material supplying section for supplying the raw material to the processing section; a cooling section for cooling the mixture in the gas phase of the processing section using a quenching gas containing an inert gas; as well as A supply unit for producing fine particles by cooling the mixture in the gas phase with the quenching gas, and supplying the surface treatment agent to the fine particles in a temperature range where the surface treatment agent does not denature.

2. The microparticle production device according to claim 1, characterized in that: The surface treatment agent is at least one of an organic acid monomer and an organic acid solution, an amine-valued dispersant monomer and an amine-valued dispersant solution, an acid-valued dispersant monomer and an acid-valued dispersant solution, an amine-valued and acid-valued dispersant monomer and a dispersant solution with an amine value and an acid value, a silane coupling agent monomer and a silane coupling agent solution, an organic solvent, an acidic substance monomer and an acidic substance solution, an alkaline substance monomer and an alkaline substance solution, a natural resin monomer and a natural resin solution, and a synthetic resin monomer and a synthetic resin solution.

3. The microparticle production device according to claim 1 or 2, characterized in that: The raw material is copper powder.

4. The microparticle production device according to claim 1 or 2, characterized in that: The raw material supply unit supplies the raw material in a dispersed particle state to the processing unit.

5. The microparticle production device according to claim 1 or 2, characterized in that: The raw material supply unit disperses the raw material in a liquid to form a slurry, and then forms droplets of the slurry and supplies the droplets to the processing unit.

6. A method for producing microparticles, which is a method for producing microparticles by using a raw material and by a thermal plasma method or a flame method, characterized in that: have: The step of preparing a mixture in a gas phase from the raw material using the thermal plasma method or the flame method, and cooling the mixture in the gas phase using a quenching gas containing an inert gas to produce a microparticle; as well as A step of supplying the surface treatment agent to the fine particles in a temperature range where the surface treatment agent does not denature.

7. The method for producing microparticles according to claim 6, wherein: The surface treatment agent is at least one of an organic acid monomer and an organic acid solution, an amine-valued dispersant monomer and an amine-valued dispersant solution, an acid-valued dispersant monomer and an acid-valued dispersant solution, an amine-valued and acid-valued dispersant monomer and a dispersant solution with an amine value and an acid value, a silane coupling agent monomer and a silane coupling agent solution, an organic solvent, an acidic substance monomer and an acidic substance solution, an alkaline substance monomer and an alkaline substance solution, a natural resin monomer and a natural resin solution, and a synthetic resin monomer and a synthetic resin solution.

8. The method for producing microparticles according to claim 6 or 7, characterized in that: The raw material is copper powder.

9. The method for producing microparticles according to claim 6 or 7, characterized in that: In the step of producing the fine particles, the raw material is made into the mixture in the gas phase using a thermal plasma flame, and the raw material is supplied to the thermal plasma flame in a state dispersed in a particle form.

10. The method for producing microparticles according to claim 6 or 7, characterized in that: In the step of producing the fine particles, the raw materials are made into the mixture in the gas phase using a thermal plasma flame, the raw materials are dispersed in a liquid to form a slurry, and the slurry is dropletized and supplied to the thermal plasma flame.

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