JP7136121B2 - compound powder - Google Patents

Description

The present invention relates to compound powder.

Compound powders containing metal powders and resin compositions are used as raw materials for various industrial products such as inductors, electromagnetic wave shields, or bonded magnets, depending on the physical properties of the metal powders (Patent Documents 1 and 2 below. reference.)

JP-A-2004-31786 JP-A-8-273916

When manufacturing an industrial product from compound powder, the compound powder is supplied and filled into a mold, or a part such as a coil is embedded in the compound powder in the mold. These processes require the compound powder to have fluidity, but conventional compound powders do not have sufficient fluidity.

An object of the present invention is to provide a compound powder having excellent fluidity.

A compound powder according to one aspect of the present invention includes a first powder containing metal-element-containing particles and a resin composition covering the metal-element-containing particles, and a second powder containing wax.

In one aspect of the invention, the wax may contain fatty acids.

In one aspect of the present invention, the metal element-containing particles may be an alloy containing iron.

In one aspect of the present invention, the resin composition may contain a thermosetting resin.

In one aspect of the present invention, the resin composition may contain an epoxy resin.

In one aspect of the present invention, the resin composition may contain a phenolic resin.

The compound powder according to one aspect of the present invention may be used for magnetic cores.

The compound powder according to one aspect of the present invention may be used for transfer molding.

According to the present invention, compound powder having excellent fluidity is provided.

Preferred embodiments of the present invention are described below. However, the present invention is by no means limited to the following embodiments.

(Overview of compound powder)
The compound powder according to the present embodiment comprises a first powder containing metal element-containing particles, a resin composition covering the individual metal element-containing particles, and a second powder containing wax. That is, each of the plurality of particles constituting the first powder has the metal element-containing particles and the resin composition covering the surface of the metal element-containing particles, and the plurality of particles constituting the second powder contain wax. The compound flour may be a mixture of the primary and secondary flours. In the compound powder, the first powder and the second powder may be uniformly mixed. The compound powder may consist of only the first powder and the second powder. The individual particles that make up the second powder may consist only of wax.

The wax contained in the second powder is liquefied by heating the compound powder according to the present embodiment at a temperature about the melting point of the wax. As a result, the entire compound powder can have excellent fluidity derived from wax. The excellent fluidity can be rephrased as the property that the heated compound powder easily flows. A conventional compound powder that does not include a wax-containing second powder is inferior in fluidity to the compound powder according to the present embodiment. For example, a compound powder composed only of particles in which a metal element-containing particle, a resin composition, and a wax are integrated has poorer fluidity than the compound powder according to the present embodiment. In other words, the compound powder composed only of the metal element-containing particles covered with the mixture of the resin composition and the wax is inferior in fluidity to the compound powder according to the present embodiment.

The second powder (individual particles that make up the second powder) can exist independently of the first powder (individual particles that make up the first powder). That is, the second powder (individual particles that make up the second powder) can be separated from the first powder (individual particles that make up the first powder). Since the second powder contains wax having a smaller specific gravity than the metal-element-containing particles, the specific gravity of the second powder tends to be smaller than that of the first powder. Therefore, it is possible to separate the second powder from the first powder by vibration or air classification. The volume ratio of the first powder and the second powder in the compound powder is not particularly limited because it can be changed depending on the use of the compound powder. The volume ratio of the first powder in the compound powder may be, for example, 90% by volume or more and 99% by volume or less. The volume ratio of the second powder in the compound powder may be, for example, 1% by volume or more and 10% by volume or less. Since the volume ratio of the first powder and the second powder in the compound powder is within the above numerical range, various physical properties derived from the first powder (for example, insulation, magnetic permeability, electric field shield value, or residual magnetic flux density, etc.) and the excellent fluidity of the compound powder are easily compatible.

The resin composition may cover part or all of the metal element-containing particles. As long as the compound powder comprises a second powder separable from the first powder, the wax may be mixed with the resin composition contained in the first powder. In other words, some of the particles that make up the first powder may have a mixture of the resin composition and wax, and metal element-containing particles covered with the mixture. The average particle size of the first powder may be, for example, 100 μm or more and 2000 μm or less. The average particle size of the metal-element-containing particles contained in the individual first particles constituting the first powder may be, for example, 1 μm or more and 300 μm or less. The average value of the thickness of the resin composition covering the metal element-containing particles may be, for example, 1 μm or more and 500 μm or less. The average value of the thickness of the resin composition may be measured using, for example, an optical microscope, a scanning electron microscope, or a transmission electron microscope. The average particle size of the second powder may be, for example, 10 μm or more and 2000 μm or less. Each average particle size may be measured, for example, with a particle size distribution meter. The shape of each particle that constitutes the first powder is not limited, but may be, for example, spherical, flat, prismatic, or acicular. The shape of each particle that constitutes the second powder is not limited, but may be, for example, spherical, flat, prismatic, or acicular.

Since the compound powder according to the present embodiment can have excellent fluidity derived from liquefied wax, it can be easily molded into a desired shape. In addition, since the wax also functions as a release agent, the compact formed from the compound powder can be easily separated from the mold without being damaged. Furthermore, when forming a compact from the compound powder according to the present embodiment, burrs are less likely to be formed. For these reasons, the compound powder according to the present embodiment is easily used for transfer molding. Transfer molding is a type of injection molding method for thermosetting resins. Transfer molding may also be referred to as pumping molding. Transfer molding includes a step of heating and fluidizing compound powder in a heating chamber, and a step of supplying (pressing) the fluidized compound powder from the heating chamber into the mold through a casting runner. good. Transfer molding involves heating and fluidizing compound powder in a heating chamber, supplying the fluidized compound powder from the heating chamber into the plunger, and passing the compound powder from the plunger through the runner into the mold. and supplying (pressing). Since the compound powder according to the present embodiment exhibits excellent fluidity when heated, it easily flows through the narrow runner (without enclosing air bubbles) without interruption, and evenly fills the space (cavity) in the mold. easy to be As a result, it becomes possible to form compacts with few defects such as voids and burrs from the compound powder. Therefore, according to the present invention, the productivity of molded articles is improved. The molding method of the compound powder is not limited to transfer molding, and may be extrusion molding, for example. Tablets formed from compound powder may be used as the starting material for the transfer molding described above.

As described below, the compound powder according to the present embodiment may be used for magnetic cores. For example, when manufacturing an inductor by transfer molding, the transfer molding includes the steps of supplying fluidized compound powder into a mold, embedding part or all of the air-core coil in the compound powder in the mold, and C. curing the compound powder in which the air core coil is embedded. Since the compound powder according to the present embodiment has excellent fluidity, it is easy to evenly fill the inside of the air-core coil, and part or all of the surface of the air-core coil is easy to be evenly covered with the compound powder. The compound powder filled inside the air-core coil becomes the magnetic core of the inductor when hardened.

Applications of the compound powder according to the present embodiment are not limited to magnetic cores of inductors. Depending on the composition or combination of metal element-containing particles contained in the compound powder, various physical properties such as electromagnetic properties and thermal conductivity of the compound powder can be freely controlled, and the compound powder can be used for various industrial products or their raw materials. can do. Industrial products manufactured using the compound powder may be, for example, automobiles, medical equipment, electronic equipment, electrical equipment, information and communication equipment, household appliances, audio equipment, and general industrial equipment. For example, when the compound powder contains Fe-Si-Cr alloy or soft magnetic powder such as ferrite as the metal element-containing particles, the compound powder is used as the above-mentioned inductor (e.g., EMI filter) or transformer material (e.g., magnetic core). may be When the compound powder contains a permanent magnet as the metal element-containing particles, the compound powder may be used as a raw material for the bonded magnet. When the compound powder contains iron and copper as the metal element-containing particles, a compact (for example, a sheet) formed from the compound powder may be used as an electromagnetic wave shield.

(Composition of first powder)
[Resin composition]
The resin composition contains at least a resin. The resin composition is a component that can include a resin, a curing agent, a curing accelerator, and additives, and may be components (non-volatile components) other than the organic solvent and the metal element-containing particles. The additive is the remaining component of the resin composition excluding the resin, the curing agent and the curing accelerator. Additives are, for example, coupling agents or flame retardants. The resin composition may contain wax as an additive. As described below, the first powder may be formed from the metal element-containing particles and the resin composition.

The resin composition functions as a binder for the metal element-containing particles, and imparts mechanical strength to the compact formed from the compound powder. For example, the resin composition contained in the first powder is filled between the metal element-containing particles and binds the metal element-containing particles to each other when the compound powder is molded at high pressure using a mold. By curing the resin composition in the molded article, the cured resin composition bonds the metal element-containing particles more firmly to each other, thereby improving the mechanical strength of the molded article.

The resin composition covering the metal element-containing particles in the first powder may contain a thermosetting resin. The thermosetting resin may be, for example, at least one selected from the group consisting of epoxy resins, phenolic resins and polyamideimide resins. If the resin composition contains both an epoxy resin and a phenolic resin, the phenolic resin may function as a curing agent for the epoxy resin. The resin composition may contain a thermoplastic resin. The thermoplastic resin may be, for example, at least one selected from the group consisting of acrylic resin, polyethylene, polypropylene, polystyrene, polyvinyl chloride, and polyethylene terephthalate. The resin composition may contain both thermosetting resins and thermoplastic resins. The resin composition may contain a silicone resin.

The content of the resin composition in the first powder may be 0.2 to 10% by mass, more preferably 0.2 to 10% by mass, relative to the mass of the entire first powder (the total mass of the metal element-containing particles and the resin composition). may be 4 to 6% by weight. When the content of the resin composition is within the above range, it is easy to achieve compatibility between the moldability of the compound powder and the tablet.

Since epoxy resins have excellent fluidity among thermosetting resins, the resin composition preferably contains epoxy resins. The epoxy resin may be, for example, a resin having two or more epoxy groups in one molecule. Among epoxy resins, crystalline epoxy resins are preferred. Although the molecular weight of the crystalline epoxy resin is relatively low, the crystalline epoxy resin has a relatively high melting point and excellent fluidity.

Epoxy resins include, for example, biphenyl-type epoxy resins, stilbene-type epoxy resins, diphenylmethane-type epoxy resins, sulfur atom-containing epoxy resins, novolak-type epoxy resins, dicyclopentadiene-type epoxy resins, salicylaldehyde-type epoxy resins, naphthols and phenols. Copolymerized epoxy resins, epoxidized aralkyl-type phenolic resins, bisphenol-type epoxy resins, glycidyl ether-type epoxy resins of alcohols, glycidyl ether-type epoxy resins of para-xylylene and/or meta-xylylene-modified phenolic resins, terpene-modified phenolic resins glycidyl ether type epoxy resin, cyclopentadiene type epoxy resin, glycidyl ether type epoxy resin of polycyclic aromatic ring-modified phenol resin, glycidyl ether type epoxy resin of naphthalene ring-containing phenol resin, glycidyl ester type epoxy resin, glycidyl type or methyl glycidyl type epoxy resin, alicyclic type epoxy resin, halogenated phenol novolac type epoxy resin, ortho-cresol novolac type epoxy resin, hydroquinone type epoxy resin, trimethylolpropane type epoxy resin, and oxidation of olefin bonds with peracid such as peracetic acid. may be at least one selected from the group consisting of linear aliphatic epoxy resins obtained by

The crystalline epoxy resin (highly crystalline epoxy resin) may be, for example, at least one selected from the group consisting of hydroquinone-type epoxy resins, bisphenol-type epoxy resins, thioether-type epoxy resins, and biphenyl-type epoxy resins. Commercially available crystalline epoxy resins include, for example, Epiclon 860, Epiclon 1050, Epiclon 1055, Epiclon 2050, Epiclon 3050, Epiclon 4050, Epiclon 7050, Epiclon HM-091, Epiclon HM-101, Epiclon N-730A, Epiclon N -740, Epiclon N-770, Epiclon N-775, Epiclon N-865, Epiclon HP-4032D, Epiclon HP-7200L, Epiclon HP-7200, Epiclon HP-7200H, Epiclon HP-7200HH, Epiclon HP-7200HHH, Epiclon HP -4700, Epiclon HP-4710, Epiclon HP-4770, Epiclon HP-5000, Epiclon HP-6000, and N500P-2 (these are trade names manufactured by DIC Corporation), NC-3000, NC-3000-L, NC -3000-H, NC-3100, CER-3000-L, NC-2000-L, XD-1000, NC-7000-L, NC-7300-L, EPPN-501H, EPPN-501HY, EPPN-502H, EOCN -1020, EOCN-102S, EOCN-103S, EOCN-104S, CER-1020, EPPN-201, BREN-S, BREN-10S (these are trade names manufactured by Nippon Kayaku Co., Ltd.), YX-4000, YX- It may be at least one selected from the group consisting of 4000H, YL4121H, and YX-8800 (the above are trade names manufactured by Mitsubishi Chemical Corporation).

The resin composition contained in the first powder may contain one of the above epoxy resins. The resin composition contained in the first powder may contain more than one of the above epoxy resins. The resin composition contained in the first powder preferably contains both a biphenyl-type epoxy resin (YX-4000H) and an ortho-cresol novolac-type epoxy resin (N500P-2) among the above epoxy resins.

Curing agents are classified into curing agents that cure epoxy resins in the range from low temperature to room temperature, and heat curing type curing agents that cure epoxy resins with heating. Curing agents that cure epoxy resins in the range from low temperature to room temperature include, for example, aliphatic polyamines, polyaminoamides, and polymercaptans. Heat-curable curing agents include, for example, aromatic polyamines, acid anhydrides, phenol novolak resins, dicyandiamide (DICY), and the like.

When a curing agent that cures the epoxy resin is used in the range from low temperature to room temperature, the glass transition point of the cured epoxy resin tends to be low and the cured epoxy resin tends to be soft. As a result, the compact formed from the compound powder also tends to become soft. On the other hand, from the viewpoint of improving the heat resistance of the molded article, the curing agent may preferably be a heat curing type curing agent, more preferably a phenol resin, and still more preferably a phenol novolac resin. In particular, by using a phenol novolac resin as a curing agent, it is easy to obtain a cured product of an epoxy resin having a high glass transition point. As a result, the heat resistance and mechanical strength of the molded product are likely to be improved.

Phenolic resins include, for example, aralkyl-type phenol resins, dicyclopentadiene-type phenol resins, salicylaldehyde-type phenol resins, novolac-type phenol resins, copolymer-type phenol resins of benzaldehyde-type phenol and aralkyl-type phenol, para-xylylene and/or meta-xylylene-modified from the group consisting of phenolic resins, melamine-modified phenolic resins, terpene-modified phenolic resins, dicyclopentadiene-type naphthol resins, cyclopentadiene-modified phenolic resins, polycyclic aromatic ring-modified phenolic resins, biphenyl-type phenolic resins, and triphenylmethane-type phenolic resins It may be at least one selected. The phenolic resin may be a copolymer composed of two or more of the above. As a commercially available phenol resin, for example, Tamanol 758 manufactured by Arakawa Chemical Industries, Ltd. or HP-850N manufactured by Hitachi Chemical Co., Ltd. may be used.

Phenol novolak resins may be resins obtained by, for example, condensation or co-condensation of phenols and/or naphthols and aldehydes under an acidic catalyst. Phenols constituting the phenolic novolak resin may be, for example, at least one selected from the group consisting of phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol and aminophenol. Naphthols constituting the phenol novolak resin may be, for example, at least one selected from the group consisting of α-naphthol, β-naphthol and dihydroxynaphthalene. The aldehydes constituting the phenol novolac resin may be, for example, at least one selected from the group consisting of formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde and salicylaldehyde.

A curing agent may be, for example, a compound having two phenolic hydroxyl groups in one molecule. The compound having two phenolic hydroxyl groups in one molecule may be, for example, at least one selected from the group consisting of resorcin, catechol, bisphenol A, bisphenol F, and substituted or unsubstituted biphenol.

The resin composition contained in the first powder may contain one of the above phenolic resins. The resin composition contained in the first powder may comprise a plurality of types of phenolic resins among those described above. The resin composition contained in the first powder may contain one of the curing agents described above. The resin composition contained in the first powder may contain a plurality of types of curing agents among those described above.

The ratio of the active group (phenolic OH group) in the curing agent that reacts with the epoxy group in the epoxy resin is preferably 0.5 to 1.5 equivalents, more preferably 1 equivalent of the epoxy group in the epoxy resin. may be 0.9 to 1.4 equivalents, more preferably 1.0 to 1.2 equivalents. If the ratio of active groups in the curing agent is less than 0.5 equivalents, the amount of OH per unit weight of the epoxy resin after curing is reduced, and the curing speed of the resin composition (epoxy resin) is reduced. If the ratio of the active groups in the curing agent is less than 0.5 equivalents, the glass transition temperature of the resulting cured product may be low, or a sufficient elastic modulus of the cured product may not be obtained. On the other hand, when the ratio of the active groups in the curing agent exceeds 1.5 equivalents, the mechanical strength of the molded article formed from the compound powder after curing tends to decrease. However, even if the ratio of active groups in the curing agent is outside the above range, the effects of the present invention can be obtained.

The curing accelerator is not particularly limited as long as it is a composition that reacts with the epoxy resin to accelerate curing of the epoxy resin. The curing accelerator may be, for example, an alkyl-substituted imidazole or imidazoles such as benzimidazole. The resin composition contained in the first powder may comprise a type of curing accelerator. The resin composition contained in the first powder may contain multiple types of curing accelerators. When the first powder contains a curing accelerator as a component of the resin composition, the moldability and releasability of the compound powder are likely to be improved. In addition, since the first powder contains a curing accelerator as a component of the resin composition, the mechanical strength of the molded body (for example, electronic parts) produced using the compound powder is improved, and the The storage stability of the compound powder in the environment is improved.

The amount of the hardening accelerator to be blended is not particularly limited as long as the hardening accelerating effect is obtained. However, from the viewpoint of improving the curability and fluidity of the resin composition when absorbing moisture, the amount of the curing accelerator is preferably 0.1 to 30 parts by mass, more than 100 parts by mass of the epoxy resin. Preferably, it may be 1 to 15 parts by mass. The content of the curing accelerator is preferably 0.001 parts by mass or more and 5 parts by mass or less with respect to the total mass of the epoxy resin and the curing agent (for example, phenol resin). When the amount of the curing accelerator is less than 0.1 part by mass, it is difficult to obtain a sufficient curing acceleration effect. If the amount of the curing accelerator is more than 30 parts by mass, the storage stability of the compound powder tends to deteriorate. However, even if the blending amount and content of the curing accelerator are outside the above range, the effects of the present invention can be obtained.

The coupling agent improves the adhesion between the resin composition and the metal element-containing particles, and improves the flexibility and mechanical strength of the compact formed from the compound powder. The coupling agent may be, for example, at least one selected from the group consisting of silane-based compounds (silane coupling agents), titanium-based compounds, aluminum compounds (aluminum chelates), and aluminum/zirconium-based compounds. The silane coupling agent may be, for example, at least one selected from the group consisting of epoxysilanes, mercaptosilanes, aminosilanes, alkylsilanes, ureidosilanes, acid anhydride-based silanes and vinylsilanes. In particular, an aminophenyl-based silane coupling agent is preferred. The compound powder may contain one of the above coupling agents, or may contain more than one of the above coupling agents.

The compound powder may contain a flame retardant because of its environmental safety, recyclability, moldability and low cost. The flame retardant is, for example, at least one selected from the group consisting of brominated flame retardants, bulb flame retardants, hydrated metal compound flame retardants, silicone flame retardants, nitrogen-containing compounds, hindered amine compounds, organometallic compounds, and aromatic engineering plastics. can be The compound powder may be provided with one of the above flame retardants, or may be provided with a plurality of the above flame retardants.

[Particles containing metal element]
The metal element-containing particles may contain, for example, at least one selected from the group consisting of simple metals, alloys and metal compounds. The metal element-containing particles may consist of, for example, at least one selected from the group consisting of simple metals, alloys and metal compounds. The alloy may contain at least one selected from the group consisting of solid solutions, eutectics and intermetallic compounds. The alloy may be, for example, stainless steel (Fe--Cr alloy, Fe--Ni--Cr alloy, etc.). The metal compound may be, for example, an oxide such as ferrite. The metal element-containing particles may contain one type of metal element or multiple types of metal elements. The metal element contained in the metal-element-containing particles may be, for example, a base metal element, a noble metal element, a transition metal element, or a rare earth element. Metal elements contained in the metal element-containing powder include, for example, iron (Fe), copper (Cu), titanium (Ti), manganese (Mn), cobalt (Co), nickel (Ni), zinc (Zn), aluminum ( Al), tin (Sn), chromium (Cr), barium (Ba), strontium (Sr), lead (Pb), silver (Ag), praseodymium (Pr), neodymium (Nd), samarium (Sm) and dysprosium ( Dy) may be at least one selected from the group consisting of. The metal-element-containing particles may contain elements other than metal elements. The metal element-containing particles may contain, for example, oxygen (O), beryllium (Be), phosphorus (P), boron (B), or silicon (Si). The metal element-containing particles may be magnetic powder. The metal element-containing particles may be soft magnetic alloys or ferromagnetic alloys. Metal element-containing particles include, for example, Fe—Si alloys, Fe—Si—Al alloys (sendust), Fe—Ni alloys (permalloy), Fe—Cu—Ni alloys (permalloy), and Fe—Co alloys. (permendur), Fe-Cr-Si alloy (electromagnetic stainless steel), Nd-Fe-B alloy (rare earth magnet), Sm-Fe-N alloy (rare earth magnet), Al-Ni-Co alloy (alnico magnet) and ferrite. Ferrites may be, for example, spinel ferrites, hexagonal ferrites, or garnet ferrites. The metal element-containing particles may be a Cu--Sn alloy, a Cu--Sn--P alloy, a Cu--Ni alloy, or a copper alloy such as a Cu--Be alloy. The metal element-containing particles may contain one of the above elements and compositions, or may contain more than one of the above elements and compositions.

The metal element-containing particles may be Fe alone. The metal element-containing particles may be an alloy containing iron (Fe-based alloy). The Fe-based alloy may be, for example, an Fe--Si--Cr-based alloy or an Nd--Fe--B based alloy. When the first powder contains at least one of Fe alone and an Fe-based alloy as the metal element-containing particles, it is easy to produce a compact having a high space factor and excellent magnetic properties from the compound powder. The metal element-containing particles may be Fe amorphous alloy. Commercially available Fe amorphous alloy powders include, for example, AW2-08, KUAMET-6B2 (manufactured by Epson Atmix Corporation), DAP MS3, DAP MS7, DAP MSA10, DAP PB, DAP PC, and DAP MKV49. , DAP 410L, DAP 430L, DAP HYB series (these are trade names manufactured by Daido Steel Co., Ltd.), MH45D, MH28D, MH25D, and MH20D (these are trade names manufactured by Kobe Steel, Ltd.). At least one may be used.

The shape of the metal element-containing particles is not particularly limited. Individual metal element-containing particles may be, for example, spherical, flattened, or acicular. The first powder may contain a plurality of types of metal element-containing particles with different average particle sizes.

(Composition of second powder)
The wax contained in the second powder may be at least one of a fatty acid such as a higher fatty acid and a fatty acid ester. The second powder may contain multiple waxes. The wax preferably contains a fatty acid from the viewpoint of easily improving the fluidity of the compound powder.

Waxes contained in the second powder include, for example, fatty acids such as montanic acid, stearic acid, 12-oxystearic acid, lauric acid, and esters thereof; zinc stearate, calcium stearate, barium stearate, aluminum stearate, stearin Fatty acid salts such as magnesium acid, calcium laurate, zinc linoleate, calcium ricinoleate, zinc 2-ethylhexoate; stearamide, oleamide, erucamide, behenamide, palmitamide, laurylamide, hydroxystearin Acid amide, methylenebisstearic acid amide, ethylenebisstearic acid amide, ethylenebislauric acid amide, distearyladipic acid amide, ethylenebisoleic acid amide, dioleyladipic acid amide, N-stearylstearic acid amide, N-oleyl stearin Fatty acid amides such as acid amides, N-stearylerucamide, methylolstearic acid amide and methylolbehenic acid amide; fatty acid esters such as butyl stearate; alcohols such as ethylene glycol and stearyl alcohol; polyethylene glycol, polypropylene glycol, polytetra Polyethers composed of methylene glycol and modified products thereof; Polysiloxanes such as silicone oil and silicone grease; Fluorine compounds such as fluorine oil, fluorine grease, and fluorine-containing resin powder; and paraffin wax, polyethylene wax, amide Waxes such as waxes, polypropylene waxes, ester waxes, carnauba, and microwaxes; may be at least one selected from the group consisting of.

As a commercial product of montan acid wax, at least one selected from the group consisting of Licowax E, Licowax OP, Licolb E and Likolb WE40 (trade names of Clariant Chemicals Co., Ltd.) may be used. At least one of Runac S-50V (titer: 56° C.) and Runac S-90V (melting point: 68° C.) manufactured by Kao Corporation may be used as a commercially available stearic acid wax. As a commercially available polyethylene wax, at least one selected from the group consisting of Licowax H12, Licowax PE520, and Licowax PED191 (trade names of Clariant Chemicals Co., Ltd.) may be used. At least one of Recolb FA1 (trade name, manufactured by Clariant Chemicals Co., Ltd.) and DISPARLON 6650 (trade name, manufactured by Kusumoto Kasei Co., Ltd.) may be used as a commercially available amide wax. The wax contained in the second powder depends on the requirements in the design of the compound powder, such as fluidity, releasability, molding temperature and pressure, wax melting point, dropping point and melt viscosity. It may be selected as appropriate. From the viewpoints of the fluidity and releasability of the compound powder, the temperature and pressure during molding, and the melting point of the wax, it is particularly preferable that the second powder contains at least one of Runac S-50V and Runac S-90V. .

(Method for producing compound powder)
By mixing the metal element-containing particles and the resin composition while heating, the resin composition adheres to a part or the entire surface of the metal element-containing particles to coat the metal element-containing particles, and the first powder is obtained. can get. After preparing the first powder, the compound powder is obtained by adding the second powder to the first powder.

A specific method for producing the first powder is not particularly limited as long as it is a method capable of covering the surface of the metal element-containing particles with the resin composition. For example, the surface of the metal element-containing particles is coated with the softened resin composition by heating and kneading the resin composition and the metal element-containing particles with a kneader or a stirrer.

In the kneading, metal element-containing particles, a resin such as an epoxy resin, a curing agent such as a phenol resin, a curing accelerator, and a coupling agent may be kneaded in a tank. After the metal element-containing particles and the coupling agent are charged into the tank and mixed, the resin, curing agent, and curing accelerator may be charged into the tank and the raw materials in the tank may be kneaded. After kneading the resin, the curing agent and the coupling agent in the tank, the curing accelerator may be put in the tank and the raw materials in the tank may be further kneaded. A mixed powder (resin mixed powder) of a resin, a curing agent, and a curing accelerator is prepared in advance, and then the metal element-containing particles and the coupling agent are kneaded to prepare a metal mixed powder, followed by The metal mixed powder and the resin mixed powder may be kneaded.

The kneading time by the kneader is preferably 5 minutes or longer, more preferably 10 minutes or longer, and even more preferably 20 minutes or longer, although it depends on the volume of the tank and the production amount of the compound powder. . The kneading time by the kneader is preferably 120 minutes or less, more preferably 60 minutes or less, and even more preferably 40 minutes or less. If the kneading time is less than 5 minutes, the kneading is insufficient, the moldability of the compound powder is impaired, and the hardness of the compound powder varies. If the kneading time exceeds 120 minutes, for example, curing of the resin composition (for example, epoxy resin and phenol resin) proceeds in the tank, and the fluidity and moldability of the compound powder are likely to be impaired. When the materials in the tank are kneaded with a kneader while being heated, the heating temperature is not limited because it depends on the composition of the resin composition. The heating temperature is, for example, preferably 50° C. or higher, more preferably 60° C. or higher, and even more preferably 80° C. or higher. The heating temperature is preferably 150° C. or lower, more preferably 120° C. or lower, and even more preferably 110° C. or lower. When the heating temperature is within the above range, the resin composition in the tank softens and easily coats the surface of the metal element-containing particles, and hardening of the resin composition during kneading is easily suppressed.

A compound powder is completed by adding a second powder (for example, ready-made wax powder) to the first powder produced by the above kneading and mixing them.

A tablet may be formed by filling the compound powder into a predetermined mold and molding by pressurization. The shape and dimensions of the tablet are not particularly limited. For example, when the tablet is cylindrical, the diameter of the tablet may be 5 mm or more, and the height (length) of the tablet may be 5 mm or more. The tablet molding pressure is, for example, preferably 500 MPa or higher, more preferably 1000 MPa or higher, and even more preferably 2000 MPa or higher.

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited by these examples.

(Example 1)
[Production of compound powder]
As metal element-containing particles, the following four types of alloy powders were placed in a PE (polyethylene) bag and sealed. In the following, numerical values shown in units of "% by mass" are contents of each component in the compound powder.
16.3 mass% carbonyl iron powder (pure iron powder, SQI manufactured by BASF Japan Co., Ltd.)
19.2 mass% iron amorphous alloy powder (KUAMET 6B2 manufactured by Epson Atmix Corporation)
52.8 mass% iron amorphous alloy powder (KUAMET 9A4-II manufactured by Epson Atmix Corporation)
7.7 mass% FeSiCr alloy powder (manufactured by Sintokogyo Co., Ltd., D50 = 2 μm)

Holding the sealing part of the bag and the bottom part of the bag with both hands, the bag was shaken for 3 minutes to mix the metal powders in the bag, thereby preparing metal element-containing particles (mixture of the above metal powders). The dimensions of the bag for the alloy powder were 470 mm x 670 mm.

As raw materials for the resin composition, the following thermosetting resin, curing agent and curing accelerator were placed in another PE bag and sealed. A resin composition was prepared by holding the sealing part of the bag and the bottom part of the bag with both hands and shaking the bag for 3 minutes to mix the raw materials in the bag. The dimensions of the bag for the resin composition were 205 x 300 mm.
1.71% by mass of ortho-cresol novolak type epoxy resin (N500P-2 manufactured by DIC Corporation)
0.43 mass% biphenyl type epoxy resin (Epikote YX-4000H manufactured by Japan Epoxy Resin Co., Ltd.)
0.91 wt% novolac curing agent (phenol novolac resin, HP-850N manufactured by Hitachi Chemical Co., Ltd.)
0.28% by mass of curing accelerator (mixture containing 2-phenyl-4-methylimidazole and phenolic resin, HP-850NP manufactured by Hitachi Chemical Co., Ltd.)

The metal element-containing particles prepared by the above method and the resin composition were placed in a tank of a twin-screw pressure kneader. Further, as a coupling agent, 0.16% by mass of long-chain methacrylsilane (silane coupling agent) was put into the tank. KBM-5803 manufactured by Shin-Etsu Chemical Co., Ltd. was used as the long-chain methacrylsilane. Subsequently, the contents of the vessel were kneaded under pressure with a kneader. The temperature in the tank during kneading was 82°C. The rotation speed of the kneader was 40 rpm. The kneading time was 1 minute. As the biaxial pressure kneader, PS1-5MHB-H type kneader, which is a pressure kneader manufactured by Nihon Spindle Mfg. Co., Ltd., was used.

The first powder was obtained by pulverizing the mass of the mixture obtained by the above kneading after natural cooling. The first powder had the metal element-containing particles and the resin composition covering the surfaces of the individual metal element-containing particles.

49.85 g of first powder and 0.15 g of wax powder (second powder) were placed in a disposable cup. The compound flour of Example 1 was obtained by mixing the first and second flours in the cup with a spatula for 3 minutes. The volume of the disposable cup was 100 cc. As the wax powder (second powder) of Example 1, 0.50% by mass of stearic acid powder and 0.01% by mass of montanic acid ester powder were used. Runac S-90V manufactured by Kao Corporation was used as stearic acid powder. As the powder of montan acid ester, “Licowax E” manufactured by Clariant Chemicals Co., Ltd. was used.

[Evaluation of liquidity]
The compound powder of Example 1 was charged into a transfer tester, and the spiral flow amount of the compound powder was measured at a mold temperature of 165°C, an injection pressure of 4.7 MPa, and a molding time of 180 seconds. The spiral flow amount is the length over which the softened or liquefied compound powder flows in the spiral curve (Archimedes' spiral) grooves formed in the mold. That is, the spiral flow amount is the flow distance of softened or liquefied compound powder. The more easily the compound powder softened or liquefied by heating flows, the larger the amount of spiral flow. In other words, the amount of spiral flow of compound powder having excellent fluidity is large. As a transfer tester, a 100KN transfer molding machine (PZ-10 type) manufactured by Kodaira Seisakusho Co., Ltd. was used. As a mold, a mold for spiral flow measurement conforming to ASTM D3123 was used. The spiral flow rate of Example 1 is shown in Table 1 below.

(Examples 2-4)
In the preparation of each of the compound powders of Examples 2 to 4, the coupling agents shown in Table 1 below were used. In addition, wax powders (second powders) shown in Table 1 below were used to prepare the compound powders of Examples 2 to 4. Compound powders of Examples 2 to 4 were individually prepared in the same manner as in Example 1 except for these matters. In the same manner as in Example 1, the spiral flow amount of each of the compound powders in Examples 2 to 4 was measured. The spiral flow rate for each of Examples 2-4 is shown in Table 1 below.

(Comparative Examples 1 to 3)
In preparing each resin composition of Comparative Examples 1 to 3, the wax powder shown in Table 1 below was uniformly mixed with the above thermosetting resin, curing agent and curing accelerator. That is, in Comparative Examples 1 to 3, the wax powder shown in Table 1 below was mixed with a thermosetting resin, a curing agent, and a curing accelerator before kneading using a kneader. However, in the preparation of the compound powders of Comparative Examples 1 to 3, no wax powder was used as the second powder. Therefore, each of the compounds of Comparative Examples 1 to 3 contained only the first powder and did not contain the second powder separable from the first powder. In other words, the individual particles that make up the compound of each of Comparative Examples 1 to 3 have a mixture of the above resin composition and wax, and metal element-containing particles coated with this mixture. was Also, in the preparation of the compound powders of Comparative Examples 1 to 3, the coupling agents shown in Table 1 below were used.

Compound powders of Comparative Examples 1 to 3 were individually prepared in the same manner as in Example 1 except for the above items. In the same manner as in Example 1, the spiral flow amount of each of the compound powders in Comparative Examples 1 to 3 was measured. The amount of spiral flow for each of Comparative Examples 1 to 3 is shown in Table 1 below.

KBM-503 in Table 1 below is a silane coupling agent (methacrylsilane) manufactured by Shin-Etsu Chemical Co., Ltd.
KBM-3063 in Table 1 below is a silane coupling agent (hexyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.
KBM-403 in Table 1 below is a silane coupling agent (3-glycidoxypropyltriethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.
KBM-13 in Table 1 below is a silane coupling agent (methyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.
Runac S-50V in the table below is a wax powder (powder of stearic acid) manufactured by Kao Corporation.

As shown in Table 1, the amount of spiral flow in any example was greater than the amount of spiral flow in each of Comparative Examples 1 to 3.

The compound powder and tablets produced from the compound powder according to the present invention are excellent in fluidity and moldability in transfer molding, and have high industrial value.

Claims (5)

a first powder containing metal element-containing particles and a resin composition covering the metal element-containing particles;
a second powder consisting only of wax;
with
The resin composition contains an epoxy resin,
used for the magnetic core,
compound powder. wherein the wax contains fatty acids;
The compound powder according to claim 1. The metal element-containing particles are an alloy containing iron,
The compound powder according to claim 1 or 2. The resin composition contains a phenolic resin,
The compound powder according to any one of claims 1-3 . used for transfer molding,
The compound powder according to any one of claims 1-4 .