Composite, molded article, cured composite, and method for producing composite

Abstract

A composite comprising a metal filler and a resin composition, wherein the metal filler comprises a first metal powder, the first metal powder comprising a plurality of first metal particles, at least a portion of the surface of the first metal particles being covered with glass containing Si, and the first metal powder having a median particle size of 1.0 μm or more and 5.0 μm or less.

Description

Technical Field

[0001] The present invention relates to a composite, a molded body, a cured product of the composite and a method for producing the composite. Background Art

[0002] Composites containing metal powder and resin compositions are used as raw materials for various industrial products due to the various physical properties of the metal powder. For example, composites are used as raw materials for inductors, sealing materials, electromagnetic shielding materials (EMI shielding materials), or bonded magnets. (See Patent Document 1 below.)

[0003] Patent Literature

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-13803 Summary of the Invention

[0005] Technical issues to be solved by the invention

[0006] When manufacturing industrial products from composites, the composite is fed into and filled into molds, or components such as coils are embedded within the composite. These processes require the composite to have adequate fluidity. However, existing composites do not have sufficient fluidity. As the particle size of the metal powder decreases, the composite's fluidity tends to decrease.

[0007] An object of the present invention is to provide a composite having excellent fluidity, a molded article containing the composite, a cured product of the composite, and a method for producing the composite.

[0008] Means for solving technical problems

[0009] A composite according to one embodiment of the present invention comprises a metal filler and a resin composition, wherein the metal filler includes a first metal powder, the first metal powder includes a plurality of first metal particles, at least a portion of the surface of the first metal particles is covered with glass containing Si, and the median particle size of the first metal powder is greater than or equal to 1.0 μm and less than or equal to 5.0 μm.

[0010] The first metal powder may be an alloy containing Fe.

[0011] The first metal particles may be spherical.

[0012] The resin composition may contain a thermosetting resin.

[0013] The composite according to one embodiment of the present invention may be in the form of a powder or a paste.

[0014] The content of the metal filler in the composite may be 90% by mass or more and less than 100% by mass.

[0015] The metal filler may further include a second metal powder, and the median particle size of the second metal powder may be larger than the median particle size of the first metal powder.

[0016] The median particle size of the second metal powder can be greater than 20.0 μm and less than 30.0 μm, the mass of the first metal powder can be M1, the mass of the second metal powder can be M2, 100×M1 / (M1+M2) can be greater than 5 and less than 30, and 100×M2 / (M1+M2) can be greater than 70 and less than 95.

[0017] The second metal powder may be an alloy containing Fe.

[0018] The second metal particles contained in the second metal powder may be spherical.

[0019] The D90 of the second metal powder may be 40 μm or more and 65 μm or less.

[0020] A molded article according to one embodiment of the present invention contains the above-mentioned composite.

[0021] The cured product of the composite material according to one embodiment of the present invention is the cured product of the composite material described above.

[0022] A method for producing a composite material according to one embodiment of the present invention is a method for producing the composite material, comprising: a step of obtaining a first mixture by mixing a metal filler and a coupling agent; a step of obtaining a second mixture by kneading a resin composition excluding the coupling agent and the first mixture while heating; a step of obtaining a solid by cooling the second mixture; and a step of pulverizing the solid material.

[0023] Another embodiment of the present invention relates to a method for producing a composite material, comprising: a step of obtaining a metal filler by mixing a first metal powder and a second metal powder; a step of obtaining a first mixture by mixing a metal filler and a coupling agent; a step of obtaining a second mixture by kneading a resin composition excluding the coupling agent and the first mixture while heating; a step of obtaining a solid by cooling the second mixture; and a step of pulverizing the solid material.

[0024] Effects of the Invention

[0025] According to the present invention, there are provided a composite having excellent fluidity, a molded article containing the composite, a cured product of the composite, and a method for producing the composite. DETAILED DESCRIPTION

[0026] Hereinafter, preferred embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments.

[0027] The composite involved in this embodiment comprises a metal filler and a resin composition, wherein the metal filler includes a first metal powder. The metal filler can also be referred to as the entire metal powder contained in the composite. The first metal powder includes a plurality of first metal particles. That is, the first metal powder refers to a plurality of first metal particles as a whole. At least a portion of the surface of the first metal particle is covered with glass containing Si (silicon). For example, at least a portion of the surface of the first metal particle can be covered by a glass film or a glass layer. The glass film or the glass layer can be composed of a plurality of glass particles containing Si. In addition to the first metal powder, the composite can further include at least one other metal powder. The resin composition can cover the surface of each metal particle constituting the metal filler. The resin composition can be present between the metal fillers, and the metal fillers can be bonded to each other by the resin composition. The composite can further include a non-metallic filler (for example, silica or a metal oxide).

[0028] As the particle size of the metal particles that make up the metal filler decreases, the gaps between the metal particles decrease. As the gaps between the metal particles decrease, the filling rate (content) of the metal filler in the composite increases. As the filling rate of the metal filler increases, the relative magnetic permeability of the composite increases. On the other hand, as the particle size of the metal particles decreases, the specific surface area of each metal particle increases. As the specific surface area of the metal particles increases, the metal filler tends to agglomerate, impairing the fluidity of the composite. Assuming that the first metal particles are not covered with glass, the first metal powder with a relatively small median particle size is particularly prone to agglomeration, and the fluidity of the composite is easily impaired due to the agglomeration of the first metal powder. However, by covering the surface of the first metal particles with glass, the agglomeration of the first metal powder can be suppressed, and the frictional force acting between the first metal particles can be reduced. As a result, the decrease in the fluidity of the composite caused by the small median particle size of the first metal powder can be suppressed. In other words, by covering the surface of the first metal particles with glass, the decrease in the fluidity of the composite caused by the increase in the filling rate of the metal filler can be suppressed.

[0029] The higher the coverage of the glass on the surface of the first metal particles, the less likely the first metal powder is to agglomerate, the easier it is to reduce the friction between the first metal particles, and the easier it is to improve the fluidity of the composite. Therefore, the entire surface of the first metal particles can be covered with glass containing Si. However, only a portion of the surface of the first metal particles can be covered with glass containing Si. The first metal powder is less likely to agglomerate and the fluidity of the composite can be improved. Therefore, the surfaces of all the first metal particles contained in the first metal powder can be covered with glass containing Si. However, only a portion of the surfaces of the first metal particles contained in the first metal powder can be covered with glass containing Si.

[0030] In addition to the first metal powder, the metal filler may include at least one other metal powder having a different median particle size than the first metal powder. For example, in addition to the first metal powder, the metal filler may also include a second metal powder. The second metal powder includes a plurality of second metal particles. In other words, the second metal powder refers to the plurality of second metal particles as a whole. The median particle size of the second metal powder is larger than that of the first metal powder. If the composite contains only the second metal powder as the metal filler, gaps are likely to form between the second metal particles, and the metal filler filling rate in the composite is likely to decrease. On the other hand, if the composite contains both the first and second metal powders as the metal filler, the first metal particles, which are smaller than the second metal particles, are more likely to fill the gaps formed between the second metal particles. As a result, the metal filler filling rate in the composite is likely to increase. The relative magnetic permeability of the composite can be easily controlled by adjusting the mass ratio of the first and second metal powders, and the relative magnetic permeability of the composite is likely to increase.

[0031] The surface of the second metal particle may not be covered with Si-containing glass. At least a portion of the surface of the second metal particle may be covered with Si-containing glass. By covering the surface of the second metal particle with glass, the aggregation of the second metal powder can be suppressed, and the decrease in the fluidity of the composite can be suppressed. The entire surface of the second metal particle may be covered with Si-containing glass. However, only a portion of the surface of the second metal particle may be covered with Si-containing glass. The surfaces of all the second metal particles contained in the second metal powder may be covered with Si-containing glass. Only a portion of the surfaces of the second metal particles contained in the second metal powder may be covered with Si-containing glass. All the metal powders contained in the composite may be covered with Si-containing glass.

[0032] The median particle size (D50) of the first metal powder is 1.0 μm to 5.0 μm, preferably 1.5 μm to 3.0 μm, and more preferably 2.17 μm to 2.31 μm. The inclusion of a fine first metal powder having this D50 in the composite easily increases the metal filler filling rate within the composite. If the D50 of the first metal powder is within the above range and the surfaces of the first metal particles are not covered with a glass film, the first metal powder tends to aggregate, and the fluidity of the composite tends to decrease. However, by covering the surfaces of the first metal particles with glass, even when the D50 of the first metal powder is within the above range, aggregation of the first metal powder can be suppressed, and the decrease in the fluidity of the composite can be suppressed. The D10 of the first metal powder can be, for example, 1.08 μm to 1.2 μm. The D90 of the first metal powder can be, for example, 3.88 μm to 4.43 μm. When the D10 or D90 of the first metal powder is within the above range, the metal filler filling rate within the composite tends to increase. The D10, D50, and D90 of the first metal powder can be calculated based on the particle size distribution of the first metal powder based on the volume of the first metal powder. The particle size distribution of the first metal powder can be measured, for example, using a laser diffraction scattering particle size distribution measuring device. The particle size distribution of the first metal powder can be measured before the first metal powder is mixed with the other components of the composite. The D10, D50, and D90 of the first metal powder are values that include the thickness of the glass. The thickness of the glass can be significantly smaller than the particle size of each first metal particle. For example, the thickness of the glass covering the first metal particles can be on the order of nanometers (nm).

[0033] The median particle size (D50) of the second metal powder can be 20.0 μm or more and 30.0 μm or less, preferably 22 μm or more and 28 μm or less, and more preferably 24.0 μm or more and 26.0 μm or less. When a fine second metal powder having the above-mentioned D50 is included in the composite, the filling rate of the metal filler in the composite is easily increased. The D10 of the second metal powder can be, for example, 6.0 μm or more and 12.0 μm or less. The D90 of the second metal powder can be, for example, 40 μm or more and 65 μm or less, preferably 45 μm or more and 65 μm or less. When the D10 or D90 of the second metal powder is within the above-mentioned range, the filling rate of the metal filler in the composite is easily increased. The D10, D50, and D90 of the second metal powder can be calculated based on the particle size distribution of the second metal powder based on the volume of the second metal powder. The particle size distribution of the second metal powder can be measured, for example, using a laser diffraction scattering particle size distribution analyzer. The particle size distribution of the second metal powder can be measured before mixing the second metal powder with the other components of the composite. When the second metal powder is covered with glass, the D10, D50, and D90 values of the second metal powder are values that include the thickness of the glass. The thickness of the glass can be significantly smaller than the particle size of the individual second metal particles. For example, the thickness of the glass covering the second metal powder can be measured in nanometers (nm).

[0034] The mass of the first metal powder can be represented as M1. The mass of the second metal powder can be represented as M2. When the D50 of the first metal powder is 1.0 μm to 5.0 μm (preferably 2.17 μm to 2.31 μm), and the D50 of the second metal powder is 20.0 μm to 30.0 μm (preferably 24.0 μm to 26.0 μm), 100×M1 / (M1+M2) can be 5 to 30, and 100×M2 / (M1+M2) can be 70 to 95. When 100×M1 / (M1+M2) and 100×M2 / (M1+M2) are within the above ranges, the first metal particles are easily filled into the gaps formed between the second metal particles, and the metal filler filling rate in the composite is easily increased. As a result, the relative magnetic permeability of the composite is easily increased. For the same reasons as above, 100×M1 / (M1+M2) may preferably be greater than or equal to 13 and less than or equal to 23, and 100×M2 / (M1+M2) may preferably be greater than or equal to 77 and less than or equal to 87.

[0035] The glass covering the surface of the first metal particle contains at least Si. The glass containing Si may further contain, for example, at least one element selected from the group consisting of O (oxygen), B (boron), Na (sodium) and Al (aluminum). The glass may contain, for example, SiO2 (silicate glass) or borosilicate glass. A plurality of particles formed by the glass containing Si may cover the surface of the first metal particle. The method for covering the surface of the first metal particle with the above-mentioned glass may be, for example, a spray dryer. That is, a surface treatment liquid containing Si may be sprayed onto the first metal powder. The surface treatment liquid containing Si may be a liquid containing the glass itself, or a liquid containing glass raw materials. The method for covering the surface of the first metal particle with the above-mentioned glass may also be an impregnation method. For example, the first metal powder may also be immersed in a surface treatment liquid containing Si. The first metal powder to which the surface treatment liquid is attached may also be heated as needed.

[0036] The surfaces of the metal particles constituting the metal filler may be covered by a coupling agent. The surface of the first metal particle may be further covered by a coupling agent. However, the coupling agent covering the metal filler is not equivalent to glass containing Si. The first metal particle may have not only a surface covered by glass, but also a surface covered by a coupling agent. As a coupling agent, a silane coupling agent is preferably used. The composite may further contain a metal powder having a surface covered by a coupling agent as a metal powder different from the first metal powder. The composite may also further contain a metal powder having a surface treated with phosphoric acid (e.g., an organophosphoric acid). For example, the composite may also further contain a metal powder having a surface covered with phosphate. The first metal particle may have not only a surface covered by glass, but also a surface treated with phosphoric acid.

[0037] The first metal powder may contain, for example, at least one selected from the group consisting of a single metal and an alloy. The alloy may contain at least one selected from the group consisting of a solid solution, a eutectic, and an intermetallic compound. The first metal powder may contain a single metal element or multiple metal elements. The metal elements contained in the first metal powder may be, for example, base metal elements, noble metal elements, transition metal elements, or rare earth elements.

[0038] The metal element contained in the first metal powder may be, for example, at least one selected from the group consisting of 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). The first metal powder may also contain elements other than metal elements. The first metal powder may also contain, for example, oxygen (O), beryllium (Be), phosphorus (P), boron (B), or silicon (Si). The first metal powder may be a soft magnetic material or a ferromagnetic material.

[0039] The first metal powder may be an alloy containing Fe. The second metal powder may also be an alloy containing Fe. All metal fillers contained in the composite may be alloys containing Fe. Since the composite contains an alloy containing Fe as a metal filler, the composite can have a high relative magnetic permeability. A composite with a high relative magnetic permeability can be suitable for use in inductors or EMI filters, for example. The first metal powder may be an alloy containing Fe, Cr, and Si. When the first metal powder is an alloy containing Fe, Cr, and Si, it is easy to suppress rusting of the first metal powder. Furthermore, when the first metal powder is an alloy containing Fe, Cr, and Si, it is easy to suppress core loss in the solidified material of the composite (for example, the portion other than the coil in the inductor). For the same reason, the second metal powder may also be an alloy containing Fe, Cr, and Si. For the same reason, all metal fillers contained in the composite may be alloys containing Fe, Cr, and Si.

[0040] The composition of the Fe-containing alloy is not limited to the above composition. For example, the first metal powder may include Fe (iron), Co (cobalt), Ni (nickel), Si (silicon), B (boron), P (phosphorus), C (carbon), and a metallic glass containing an element α and an element β, where the element α may be at least one element selected from the group consisting of Nb (niobium) and Mo (molybdenum), and the element β may be at least one element selected from the group consisting of Cr (chromium) and Zr (zirconium). The first metal powder may also include at least one element selected from the group consisting of an Fe-Si alloy, an Fe-Si-Al alloy (Senduum), an Fe-Ni alloy (Permalloy), an Fe-Cu-Ni alloy (Permalloy), and an Fe-Co alloy (Permentur).

[0041] The first metal powder may be Fe alone. For example, the first metal powder may include at least one of amorphous iron powder and carbonyl iron powder.

[0042] The first metal powder may include a metal magnet formed by at least one selected from the group consisting of Nd-Fe-B alloy (rare earth magnet), Sm-Co alloy (rare earth magnet), Sm-Fe-N alloy (rare earth magnet) and Al-Ni-Co alloy (aluminum nickel cobalt magnet).

[0043] The second metal powder may include at least one selected from the group consisting of the aforementioned metals and their compounds. The composition of the second metal powder may be the same as that of the first metal powder. The composition of the second metal powder may also be different from that of the first metal powder. The metal filler may include at least one other metal powder having a composition different from that of the first and second metal powders. The other metal powder may include at least one selected from the group consisting of the aforementioned metals and their compounds.

[0044] The first metal powder may comprise at least one of nanocrystals and amorphous metals. That is, the first metal particles constituting the first metal powder may comprise at least one of nanocrystals and amorphous metals. The amorphous metal may be metallic glass. At least a portion of the first metal particles may be single crystal. At least a portion of the first metal particles may be polycrystalline. At least a portion of the first metal particles may be amorphous metal. When the first metal particles are amorphous metal, it is easy to reduce core loss in a device (e.g., an inductor) made of the composite.

[0045] The second metal powder may comprise at least one of nanocrystals and amorphous metals. That is, the second metal particles constituting the second metal powder may comprise at least one of nanocrystals and amorphous metals. The amorphous metal may be metallic glass. At least a portion of the second metal particles may be single crystal. At least a portion of the second metal particles may be polycrystalline. At least a portion of the second metal particles may be amorphous metal. When the second metal particles are amorphous metal, it is easy to reduce core loss in a device (e.g., an inductor) made from the composite.

[0046] At least a portion of the first metal particles may be approximately spherical. All of the first metal particles may be approximately spherical. When the first metal particles are approximately spherical, the surface of the first metal particles is smooth. As a result, friction between the metal fillers is easily reduced, and the fluidity of the composite is easily improved. For similar reasons, at least a portion of the second metal particles may be approximately spherical. All of the second metal particles may be approximately spherical. For similar reasons, all of the metal fillers contained in the composite may be approximately spherical. Whether the first metal particles are spherical can be determined based on the sphericity of the metal fillers. The sphericity of the metal fillers can be measured using a particle shape image analyzer. For example, the PITA-04 manufactured by SEISHIN.CO., LTD. can be used as a particle shape image analyzer. The sphericity of the metal fillers is measured with the metal fillers dispersed in pure water. The metal fillers are dispersed in the pure water by generating ultrasonic waves in the water for a predetermined time (e.g., 60 seconds). By using a certain index in the calculation of the sphericity of the metal fillers, the influence of metal filler agglomerates (secondary particles) can be eliminated. The shapes of the first and second metal particles are not limited to spherical.

[0047] The content of the metal filler in the composite can be greater than 90% by mass and less than 100% by mass, greater than 93% by mass and less than 99.5% by mass, or greater than 94% by mass and less than 99.5% by mass. As the content of the metal filler increases, the relative magnetic permeability of the composite tends to increase. On the other hand, as the content of the metal filler increases, the fluidity of the composite tends to decrease. However, even in the case where the content of the metal filler is high, by including the first metal powder in the composite, both high relative magnetic permeability and high fluidity can be achieved. The content of the metal filler in the composite can also be referred to as the filling rate of the metal filler in the composite. The filling rate of the metal filler in the composite can also be referred to as the space factor of the metal filler in the composite. Relative to the total mass of the composite, the content of the resin composition in the composite can be greater than 0% by mass and less than 10% by mass, greater than 0.5% by mass and less than 7% by mass, or greater than 0.5% by mass and less than 6% by mass.

[0048] The resin composition may be a composition that can contain a resin, a curing agent, a curing accelerator and an additive. The resin composition may be the remaining component (non-volatile component) other than the organic solvent and the metal filler. The additive may be the remaining component other than the resin, the curing agent and the curing accelerator in the resin composition. The additive is, for example, a coupling agent or a flame retardant. The resin composition may also contain wax as an additive. The mixture of the above-mentioned metal filler and the uncured resin composition is equivalent to a composite. The composite may be a powder. The composite may also be a tablet. The composite may be a paste. By molding the composite, a molded body containing the composite is formed. By curing the resin composition in the molded body, a cured product of the composite can be obtained. The resin composition described below may be regarded as an uncured resin composition contained in the composite.

[0049] The resin composition functions as a binder for the metal fillers, imparting mechanical strength to the molded and cured products formed from the composite. For example, when the composite is molded under high pressure using a mold, the resin composition fills the gaps between the metal fillers, bonding them together. Curing the resin composition in the molded composite creates a solid bond between the metal fillers.

[0050] The resin composition may contain a thermosetting resin. For example, the thermosetting resin may be at least one selected from the group consisting of epoxy resins, phenolic resins, and polyamide-imide resins. When the resin composition contains both epoxy resins and phenolic resins, the phenolic resin may also function as a curing agent for the epoxy resin. The resin composition may also contain a thermoplastic resin. For example, the thermoplastic resin may be at least one selected from the group consisting of acrylic resins, polyethylene, polypropylene, polystyrene, polyvinyl chloride, and polyethylene terephthalate. The resin composition may contain both thermosetting resins and thermoplastic resins. The resin composition may also contain a silicone resin.

[0051] The epoxy resin may be, for example, a resin having two or more epoxy groups in one molecule. The epoxy resin may be, for example, a biphenyl epoxy resin, a stilbene epoxy resin, a diphenylmethane epoxy resin, a sulfur-containing epoxy resin, a novolac epoxy resin, a dicyclopentadiene epoxy resin, a hydroxyl aldehyde epoxy resin, a copolymerized epoxy resin of naphthols and phenols, an epoxide of an aralkyl phenolic resin, a bisphenol epoxy resin, an alcohol glycidyl ether epoxy resin, a glycidyl ether epoxy resin of a p-xylene and / or m-xylene-modified phenolic resin, or a glycidyl ether epoxy resin of a terpene-modified phenolic resin. , cyclopentadiene type epoxy resin, polycyclic aromatic ring modified phenolic resin glycidyl ether type epoxy resin, naphthalene ring-containing phenolic resin glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, glycidyl or methyl glycidyl type epoxy resin, alicyclic epoxy resin, halogenated phenol novolac type epoxy resin, o-cresol novolac type epoxy resin, hydroquinone type epoxy resin, trimethylolpropane type epoxy resin and linear aliphatic epoxy resin obtained by oxidizing olefin bonds with peracids such as peracetic acid.

[0052] Among epoxy resins, crystalline epoxy resins are preferred. Although crystalline epoxy resins have relatively low molecular weights, they have relatively high melting points and excellent fluidity. Crystalline epoxy resins (highly crystalline epoxy resins) 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 products of crystalline epoxy resins may be selected from, 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 (all 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 (all trade names manufactured by Nippon Kayaku Co., Ltd.), YX-4000, YX-4000H, YL4121H, and YX-8800 (all trade names manufactured by Mitsubishi Chemical Corporation).

[0053] The resin composition may contain one or more of the epoxy resins mentioned above.

[0054] Curing agents are categorized into two types: those that cure resins at temperatures between low and room temperature, and heat-curing curing agents that cure resins upon heating. Examples of curing agents that cure resins at temperatures between low and room temperature include aliphatic polyamines, polyaminoamides, and polythiols. Examples of heat-curing curing agents include aromatic polyamines, acid anhydrides, phenolic resins, phenol novolac resins, and dicyandiamide (DICY).

[0055] The phenolic resin can be, for example, at least one selected from the group consisting of an aralkyl phenolic resin, a dicyclopentadiene phenolic resin, a hydroxy-aldehyde phenolic resin, a novolac phenolic resin, a copolymerized phenolic resin of benzaldehyde phenol and an aralkyl phenol, a p-xylene and / or m-xylene modified phenolic resin, a melamine modified phenolic resin, a terpene modified phenolic resin, a dicyclopentadiene naphthol resin, a cyclopentadiene modified phenolic resin, a polycyclic aromatic ring modified phenolic resin, a biphenyl phenolic resin, and a triphenylmethane phenolic resin. The phenolic resin can also be a copolymer composed of two or more of the above. As commercially available products of the phenolic resin, for example, Tam anol 758 manufactured by Arakawa Chemical Industries, Ltd. or HP-850N manufactured by Hitachi Chemical Company, Ltd. can be used.

[0056] The phenol novolac resin may be, for example, a resin obtained by condensing or co-condensing phenols and / or naphthols with aldehydes under an acidic catalyst. The phenols constituting the phenol novolac 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. The naphthols constituting the phenol novolac 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 salicylic aldehyde.

[0057] The 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 resorcinol, catechol, bisphenol A, bisphenol F, and substituted or unsubstituted bisphenols.

[0058] The resin composition may contain one of the phenolic resins listed above. The resin composition may also contain multiple phenolic resins listed above. The resin composition may contain one of the curing agents listed above. The resin composition may also contain multiple curing agents listed above. Commercially available phenolic resins include, for example, Tamanol 758 manufactured by Arakawa Chemical Industries, Ltd. or HP-850N manufactured by Hitachi Chemical Company, Ltd.

[0059] The ratio of the active group (phenolic OH group) in the curing agent that reacts with the epoxy group in the epoxy resin relative to 1 equivalent of the epoxy group in the epoxy resin is preferably 0.5 to 1.5 equivalents, more preferably 0.9 to 1.4 equivalents, and even more preferably 1.0 to 1.2 equivalents. When the ratio of the active group in the curing agent is less than 0.5 equivalents, the amount of OH per unit weight of the cured epoxy resin decreases, and the curing speed of the resin composition (epoxy resin) decreases. Moreover, when the ratio of the active group in the curing agent is less than 0.5 equivalents, the glass transition temperature of the obtained cured product becomes low, or the sufficient elastic modulus of the cured product cannot be obtained. On the other hand, when the ratio of the active group in the curing agent exceeds 1.5 equivalents, the mechanical strength of the sealing material formed by the composite tends to decrease. However, even when the ratio of the active group in the curing agent is outside the above range, the effect of the present invention can be obtained.

[0060] The curing accelerator is not limited to any composition that reacts with the epoxy resin and promotes the curing of the epoxy resin. The curing accelerator can be, for example, an imidazole such as an alkyl-substituted imidazole or benzimidazole. The resin composition can have one curing accelerator. The resin composition can also have multiple curing accelerators. By containing a curing accelerator in the resin composition, it is easy to improve the formability and demoulding properties of the composite. By containing a curing accelerator in the resin composition, the mechanical strength of the sealing material manufactured using the composite is improved, or the storage stability of the composite under high temperature and high humidity environments is improved. As commercially available imidazole curing accelerators, for example, at least one selected from the group consisting of 2MZ-H, C11Z, C17Z, 1,2DMZ, 2E4MZ, 2PZ-PW, 2P4MZ, 1B2MZ, 1B2PZ, 2MZ-CN, C11Z-CN, 2E4MZ-CN, 2PZ-CN, C11Z-CNS, 2P4MHZ, TPZ, and SFZ (all trade names manufactured by SHIKOKU CHEMICALS CORPORATION) can be used. Among them, imidazole curing accelerators having a long-chain alkyl group are preferred, and C11Z-CN (1-cyanoethyl-2-undecylimidazole) is preferred.

[0061] The amount of curing accelerator is not particularly limited as long as it is an amount that can obtain a curing acceleration effect. However, from the viewpoint of improving the curability and fluidity of the resin composition during moisture absorption, the amount of curing accelerator can be preferably 0.1 to 30 parts by mass, more preferably 1 to 15 parts by mass relative to 100 parts by mass of epoxy resin. Relative to the total mass of epoxy resin and curing agent (such as phenolic resin), the content of curing accelerator is preferably 0.001 parts by mass and less than 5 parts by mass. When the amount of curing accelerator is less than 0.1 parts by mass, it is difficult to obtain a sufficient curing acceleration effect. When the amount of curing accelerator exceeds 30 parts by mass, the storage stability of the composite is easily reduced. However, even when the amount and content of curing accelerator are outside the above range, the effect of the present invention can be obtained.

[0062] The coupling agent improves the adhesion between the resin composition and the metal filler, and improves the flexibility and mechanical strength of the sealing material formed by the composite. The coupling agent can be, for example, at least one selected from the group consisting of a silane compound (silane coupling agent), a titanium compound, an aluminum compound (aluminum chelate) and an aluminum / zirconium compound. The silane coupling agent can be, for example, at least one selected from the group consisting of epoxy silane, mercapto silane, aminosilane, alkyl silane, urea silane, anhydride silane and vinyl silane. Particularly preferred are aminophenyl silane coupling agents. The composite can have one of the above-mentioned coupling agents or a variety of the above-mentioned coupling agents.

[0063] To enhance the composite's environmental safety, recyclability, moldability, and low cost, the composite may contain a flame retardant. For example, the flame retardant may be at least one selected from the group consisting of brominated flame retardants, phosphorus flame retardants, hydrated metal compound flame retardants, silicone flame retardants, nitrogen-containing compounds, hindered amine compounds, organometallic compounds, and aromatic engineering plastics. The composite may contain one or more of these flame retardants.

[0064] The resin composition may contain wax. The wax improves the fluidity of the composite during molding (e.g., transfer molding) and functions as a mold release agent. The wax may be at least one of a fatty acid such as a higher fatty acid and a fatty acid ester.

[0065] The wax may be, for example, a fatty acid selected from montanic acid, stearic acid, 12-oxystearic acid, lauric acid, or an ester thereof; a fatty acid salt such as zinc stearate, calcium stearate, barium stearate, aluminum stearate, magnesium stearate, calcium laurate, zinc linoleate, calcium ricinoleate, or zinc 2-ethylhexanoate; stearic acid amide, oleic acid amide, erucic acid amide, behenic acid amide, palmitic acid amide, lauric acid amide, hydroxystearic acid amide, methylene bisstearic acid amide, ethylene bisstearic acid amide, ethylene bislauric acid amide, distearyl adipamide, ethylene bisoleic acid amide, or dioleyl adipamide. Fatty acid amides such as butyl stearamide, N-stearyl stearamide, N-oleyl stearamide, N-stearyl erucamide, hydroxymethyl stearamide, and hydroxymethyl behenamide; fatty acid esters such as butyl stearate; alcohols such as ethylene glycol and stearyl alcohol; polyethers formed from polyethylene glycol, polypropylene glycol, polytetramethylene glycol and modifications thereof; polysiloxanes such as silicone oil and silicone grease; fluorine compounds such as fluorine oil, fluorine grease, and fluorine-containing resin powder; and at least one of the group consisting of waxes such as paraffin wax, polyethylene wax, amide wax, polypropylene wax, ester wax, carnauba, and micro wax.

[0066] The composite material of the present embodiment has excellent fluidity. Therefore, the composite material of the present embodiment can be easily processed into a desired shape by extrusion molding or transfer molding (transfer molding). According to the composition of the metal filler or the resin composition, the physical properties of the molded body containing the composite material or the cured product of the composite material can be freely controlled. The physical properties are, for example, electromagnetic properties or thermal conductivity. For these reasons, the composite material can be used in various industrial products or their raw materials. The industrial products manufactured using the composite material can be, for example, automobiles, medical equipment, electronic equipment, electrical equipment, information and communication equipment, home appliances, audio equipment and general industrial equipment. When the composite material contains a soft magnetic body as a metal filler, the composite material can be used as a sealing material for an inductor, a magnetic core for an inductor, an EMI shielding member or a magnetic core for a transformer. When the composite material contains a metal magnet as a metal filler, the composite material can be used as a raw material for a bonded magnet.

[0067] (Method for producing composite)

[0068] An example of the method for producing the composite material according to the present invention will be described below. However, the method for producing the composite material according to the present invention is not limited to the following method.

[0069] The method for producing a composite material according to the present embodiment includes a first mixing step, a second mixing step, a cooling step, and a pulverizing step.

[0070] In the first mixing step, a metal filler and a coupling agent are mixed to obtain a first mixture. Through the first mixing step, the coupling agent bonds to the surface of each metal particle constituting the metal filler. That is, a portion or the entire surface of each metal particle is covered with the coupling agent. As a result, the surface of the metal filler is easily covered by the resin composition via the coupling agent, the metal filler is easily dispersed in the composite, and the metal filler filling rate in the composite is easily increased.

[0071] The metal filler mixed with the coupling agent includes at least a first metal powder. The surface of each first metal particle contained in the first metal powder is pre-covered with glass containing Si. The filling rate of the metal filler in the composite is easy to increase, so the metal filler mixed with the coupling agent preferably includes both the first metal powder and the second metal powder. The surface of each second metal particle contained in the second metal powder may not be covered with glass containing Si. The surface of each second metal particle contained in the second metal powder may be pre-covered with glass containing Si. In the case where the metal filler includes both the first metal powder and the second metal powder, the metal filler can be obtained by mixing the first metal powder and the second metal powder before the first mixing step.

[0072] In a second mixing step following the first mixing step, a second mixture can be obtained by mixing the resin composition other than the coupling agent with the first mixture while heating. That is, in the second mixing step, the components other than the coupling agent in the resin composition are mixed with the first mixture. The components other than the coupling agent in the resin composition may be, for example, a thermosetting resin, a curing agent, a curing accelerator, and an additive. The additive may be, for example, at least one of a wax and a flame retardant. Before the second mixing step, a resin mixture may be obtained by pre-mixing a thermosetting resin, a curing agent, a curing accelerator, and an additive. Furthermore, in the second mixing step, the second mixture may be obtained by mixing the resin mixture and the first mixture while heating. The second mixture may be a paste.

[0073] The temperature of the second mixture in the second mixing process can be adjusted according to the composition of the resin composition. The temperature of the second mixture in the second mixing process can be, for example, more than 50°C and less than 150°C, preferably more than 60°C and less than 120°C, more preferably more than 80°C and less than 110°C. When the temperature of the second mixture is within the above range, the resin composition in the second mixture is easily softened, the resin composition easily covers the surface of the metal particles, and it is easy to suppress the solidification of the resin composition in the second mixing process. When the temperature of the second mixture is too low, the second mixture is not fully mixed, the formability of the composite is impaired, and the degree of cure of the composite is deviated. When the temperature of the second mixture is too high, the resin composition is cured in the second mixing process, and the fluidity and formability of the composite are easily impaired. The time for mixing the second mixture in the second mixing process can be adjusted according to the performance of the mixing method (for example, a biaxial pressure kneader) used in the second mixing process and the volume of the second mixture.

[0074] In the cooling step after the second mixing step, the second mixture is cooled to obtain a solid. The second mixture may be cooled at room temperature.

[0075] In the pulverization step following the cooling step, the solid material is pulverized. The powder obtained by pulverizing the solid material can itself be used as a composite. The powder obtained in the pulverization step can also be classified to remove coarse particles. The powder obtained in the pulverization step can also be formed into tablets made of the composite.

[0076] The composite is completed through the above manufacturing method.

[0077] Example

[0078] The present invention will be described in further detail with reference to the following examples and comparative examples. However, the present invention is not limited to the following examples.

[0079] (Example 1)

[0080] [Production of composite powder]

[0081] <Preparation of Metal Filler>

[0082] Place the first and second metal powders into a bag and seal the bag. Shake the bag for 3 minutes to mix the first and second metal powders, thereby obtaining a metal filler. The bag is made of polyethylene (PE) and measures 470 mm x 670 mm.

[0083] The first metal powder is composed of a plurality of first metal particles. The median particle size of the first metal powder is not less than 2.17 μm and not more than 2.31 μm. Each first metal particle is composed of an alloy particle and a plurality of glass particles covering the surface of the alloy particle. Each alloy particle contains Fe, Cr, and Si. Each glass particle covering the surface of the alloy particle contains Si. The particle size of each glass particle is significantly smaller than the median particle size of the first metal powder. Each first metal particle is substantially spherical. The mass M1 of the first metal powder is 770.8 g.

[0084] The second metal powder used was an amorphous alloy powder containing iron. The iron-containing amorphous alloy powder was KUAMET 9A4-II manufactured by EPSON ATMIX CORPORATION. The median particle size of the second metal powder was 25.0 μm. The amorphous alloy particles (second metal particles) that comprised the second metal powder were approximately spherical. The mass M2 of the second metal powder was 3511.2 g.

[0085] 100×M1 / (M1+M2) is 18. 100×M2 / (M1+M2) is 82.

[0086] <First Mixing Step>

[0087] Methacrylsilane (silane coupling agent) was added to the metal filler in the bag. The mass of the methacryloylsilane was 5.43 g. The methacryloylsilane was KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd. The bag was shaken for three minutes to mix the metal filler and methacryloylsilane, thereby forming a first mixture. This first mixing step covered the surfaces of the metal particles that comprised the metal filler with methacryloylsilane.

[0088] <Second mixing step>

[0089] A bag different from the above-mentioned bag was used in the second mixing step. The size of the bag used in the second mixing step was 205×300 mm. The bag was made of PE (polyethylene). Thermosetting resin, curing agent, curing accelerator and wax powder were placed in the bag and the bag was sealed. The contents of the bag were mixed by shaking the bag with both hands for 3 minutes to obtain a resin mixture. The mass and composition of the thermosetting resin, curing agent, curing accelerator and wax powder are shown below. The following NC3000-H and NC3000 are both epoxy resins.

[0090] 90.9 g of thermosetting resin (NC3000-H manufactured by Nippon Kayaku Co., Ltd.)

[0091] 39.0 g of thermosetting resin (NC3000 manufactured by Nippon Kayaku Co., Ltd.)

[0092] 48.2 g curing agent (phenol novolac resin, HP-850N manufactured by Hitachi Chemical Company, Ltd.)

[0093] 2.6 g curing accelerator (imidazole epoxy resin curing agent, C17Z manufactured by Shikoku Kasei Co., Ltd.)

[0094] 15.7 g wax powder (Licowax E manufactured by Clariant Chemicals Co., Ltd.)

[0095] The first mixture and the resin mixture were placed in the tank of a biaxial pressure kneader. A second mixture was obtained by kneading the first mixture and the resin mixture in the tank while applying pressure using the kneader. The second mixture was a paste. The temperature in the tank during kneading was 82°C. The kneader speed was 40 rpm. The kneading time was 1 minute. A pressure kneader (PS1-5MHB-H type kneader) manufactured by Nihon Spindle Manufacturing Co., Ltd. (formerly MORIYAMA SEISAKUSHO CO., LTD.) was used as the biaxial pressure kneader.

[0096] Cooling process

[0097] By cooling the second mixture at room temperature, a solid was obtained.

[0098] <Crushing process>

[0099] The solid material was pulverized to obtain a powdered composite. Coarse particles were removed from the composite by classification using a sieve with a 2 mm aperture.

[0100] By the above method, a composite material of Example 1 was produced. The content (space factor) of the metal filler in the composite material was 95.5% by mass.

[0101] [Evaluation of liquidity]

[0102] The compound of Example 1 was loaded into a transfer tester. The spiral flow rate of the compound was measured at a mold temperature of 175°C, an injection pressure of 4.1 MPa, and a molding time of 420 seconds. The spiral flow rate refers to the length of the compound flowing in the groove formed in the mold. That is, the spiral flow rate refers to the flow distance of the softened or liquefied compound. The shape of the groove in which the compound flows is a vortex curve (Archimedes spiral). The easier the compound flows, the greater the spiral flow rate. That is, the spiral flow rate of the compound with excellent fluidity is large. As a transfer tester, a 100KN transfer molding machine (PZ-10 model) manufactured by Kodaira Seisakusho Co., Ltd. was used. As a mold, a mold for spiral flow measurement according to ASTM D3123 was used. The spiral flow rate of Example 1 is shown in Table 1 below.

[0103] [Measurement of relative magnetic permeability]

[0104] Using a transfer testing machine and a mold, a ring-shaped molded body was produced from the compound of Example 1. The mold temperature was 175°C, the injection pressure was 4.1 MPa, and the molding time was 420 seconds. The dimensions of the molded body were an outer diameter of 20 mm, an inner diameter of 12 mm, and a thickness of 2 mm. As a transfer testing machine, a 100KN transfer molding machine (PZ-10 model) manufactured by Kodaira Seisakusho Co., Ltd. was used. As a mold, a mold that can obtain a ring shape was used. The primary side winding was wound 5 turns on the above molded body, and the secondary side winding was wound 5 turns on the above molded body. The relative magnetic permeability μ of the sample produced by the above method was measured. S The relative magnetic permeability μ of Example 1 S The relative magnetic permeability μ is shown in Table 1 below. S The measurement was performed using a BH Analyzer (SY-8258) manufactured by IWATSUELECTRIC CO., LTD. The frequency for measuring the relative magnetic permeability was 1 MHz.

[0105] (Example 2)

[0106] By varying the mass ratio of the first mixture and the resin mixture, the metal filler content in the composite of Example 2 was adjusted to 95.0% by mass. A composite of Example 2 was prepared using the same method as Example 1, except for the metal filler content. The spiral flow rate of the composite of Example 2 was measured using the same method as Example 1. The spiral flow rate of Example 2 is shown in Table 1 below. The relative magnetic permeability of the composite of Example 2 was measured using the same method as Example 1. The relative magnetic permeability of Example 2 is shown in Table 1 below.

[0107] (Comparative Example 1)

[0108] As the metal filler in Comparative Example 1, only the second metal powder was used. As in Example 1, the metal filler content in the composite of Comparative Example 1 was adjusted to 95.5% by mass. The composite of Comparative Example 1 was prepared using the same method as in Example 1, except for the metal filler. The spiral flow rate of the composite of Comparative Example 1 was measured using the same method as in Example 1. The spiral flow rate of Comparative Example 1 is shown in Table 1 below. The relative magnetic permeability of the composite of Comparative Example 1 was measured using the same method as in Example 1. The relative magnetic permeability of Comparative Example 1 is shown in Table 1 below.

[0109] (Comparative Example 2)

[0110] As the metal filler in Comparative Example 2, only the second metal powder was used. As in Example 2, the metal filler content in the composite of Comparative Example 2 was adjusted to 95.0% by mass. A composite of Comparative Example 2 was prepared in the same manner as in Example 1, except for the metal filler and its content. The spiral flow rate of the composite of Comparative Example 2 was measured in the same manner as in Example 1. The spiral flow rate of Comparative Example 2 is shown in Table 1 below. The relative magnetic permeability of the composite of Comparative Example 2 was measured in the same manner as in Example 1. The relative magnetic permeability of Comparative Example 2 is shown in Table 1 below.

[0111] [Table 1]

[0112]

[0113] Industrial applicability

[0114] The compound according to the present invention has excellent fluidity and can therefore be easily molded into shapes corresponding to various industrial products.

Claims

1. A composite comprising a metal filler and a resin composition, wherein the metal filler comprises a first metal powder and a second metal powder. The first metal powder comprises a plurality of first metal particles, At least a portion of the surface of the first metal particle is covered with a nanoscale glass film composed of glass particles containing Si. The median particle size of the first metal powder is 1.0 μm or more and 5.0 μm or less. The metal filler is a soft magnetic body. The median particle size of the second metal powder is larger than the median particle size of the first metal powder, The median particle size of the second metal powder is 20.0 μm or more and 28 μm or less. The resin composition comprises an epoxy resin and a curing accelerator, The curing accelerator comprises imidazoles.

2. The composite according to claim 1, wherein The first metal powder is an alloy containing Fe.

3. The composite according to claim 1, wherein The first metal particles are spherical. The composite according to claim 1 , wherein The resin composition contains a thermosetting resin. The compound according to claim 1 , which is in the form of a powder or a paste. The composite according to claim 1 , wherein: The content of the metal filler is 90 mass % or more and less than 100 mass %.

7. The composite according to claim 1, wherein The mass of the first metal powder is M1, The mass of the second metal powder is M2, 100×M1 / (M1+M2) is 5 or more and 30 or less, 100×M2 / (M1+M2) is greater than or equal to 70 and less than or equal to 95.

8. The composite according to claim 1, wherein The second metal powder is an alloy containing Fe.

9. The composite according to claim 1, wherein The second metal particles included in the second metal powder are spherical.

10. The composite according to claim 1, wherein The D90 of the second metal powder is 40 μm or more and 65 μm or less.

11. A shaped body comprising the compound according to any one of claims 1 to 10. 12 . A cured product, which is the cured product of the composite according to claim 1 .

13. A method for producing a composite, which is a method for producing the composite according to any one of claims 1 to 10, comprising: A step of obtaining a first mixture by mixing the metal filler and the coupling agent; a step of obtaining a second mixture by kneading the resin composition excluding the coupling agent and the first mixture while heating; A step of obtaining a solid by cooling the second mixture; and The step of crushing the solid matter.

14. A method for producing a composite, which is a method for producing the composite according to any one of claims 1 to 10, comprising: a step of obtaining the metal filler by mixing the first metal powder and the second metal powder; A step of obtaining a first mixture by mixing the metal filler and the coupling agent; a step of obtaining a second mixture by kneading the resin composition excluding the coupling agent and the first mixture while heating; A step of obtaining a solid by cooling the second mixture; and The step of crushing the solid matter.

Images