Composites, molded articles and cured products of composites

Abstract

The composite of one side of the present invention comprises metal powder and a resin composition containing epoxy resin, curing agent and coupling agent. The coupling agent comprises a first silane compound and a second silane compound. The first silane compound has a functional group selected from epoxy group, amino group, urea group and isocyanate group. The second silane compound has a chain hydrocarbon group having 6 or more carbon atoms. The content of metal powder is 90% by mass or more and less than 100% by mass.

Description

Technical Field

[0001] This invention relates to a composite, a molded body, and a cured product of the composite. Background Technology

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

[0003] Previous technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-13803 Summary of the Invention

[0006] The technical problem to be solved by the invention

[0007] When manufacturing industrial products from composites, the composite is supplied and filled into a mold through a flow path, or components such as coils are embedded in the composite within the mold. In these processes, the flowability of the composite is required. The flowability of the composite increases as the content of metal powder in the composite decreases, but to improve the magnetic properties of the composite used in inductors and the like, a high content of metal powder (filling rate) is desirable. However, as the content of metal powder in the composite increases, the melt viscosity of the composite increases, and the flowability of the composite decreases. Furthermore, during the heating process of the molded body made from the composite, cracks may form on the molded body. Therefore, the composite is required to have excellent flowability during molding and to improve the mechanical properties of the molded body at high temperatures (e.g., high-temperature bending properties).

[0008] The present invention was made in view of the above circumstances, and its object is to provide a composite capable of forming a molded article with excellent flowability during molding and excellent mechanical properties at high temperature, a molded article using the composite, and a cured product of the composite.

[0009] means for solving technical problems

[0010] The composite of one side of the present invention comprises metal powder and a resin composition containing epoxy resin, curing agent and silane coupling agent, wherein the silane coupling agent comprises a first silane compound and a second silane compound, the first silane compound having a functional group selected from epoxy group, amino group, urea group and isocyanate group, the second silane compound having a chain hydrocarbon group having 6 or more carbon atoms, and the content of metal powder being 90% by mass or more and less than 100% by mass.

[0011] The molded body on one side of the present invention comprises the above-described composite. The cured product on one side of the present invention is a cured product of the above-described composite.

[0012] Invention Effects

[0013] According to the present invention, a composite capable of forming a molded article with excellent flowability during molding and excellent mechanical properties at high temperatures, a molded article using the composite, and a cured product of the composite can be provided. Detailed Implementation

[0014] The preferred embodiments of the present invention will be described below. However, the present invention is not limited to any of the embodiments described below.

[0015] [complex]

[0016] The composite of this embodiment comprises a metal powder and a resin composition. The metal powder may contain at least one component selected from the group consisting of metal monomers, alloys, amorphous powders, and metal compounds. The resin composition contains at least an epoxy resin, a curing agent, and a coupling agent. The coupling agent comprises a first silane compound and a second silane compound, the first silane compound having a functional group selected from epoxy, amino, urea, and isocyanate groups, and the second silane compound having a chain hydrocarbon group having 6 or more carbon atoms. In the composite, the metal powder, epoxy resin, curing agent, and coupling agent are mixed. The resin composition may further contain curing accelerators, release agents, additives, etc., as other components. The resin composition may contain epoxy resin, curing agent, coupling agent, curing accelerator, release agent, and additives, excluding organic solvents and metal powder (non-volatile components). The additives are the remaining components in the resin composition besides resin, release agent, curing agent, curing accelerator, and coupling agent. Additives may be, for example, flame retardants, lubricants, etc. The composite may be a powder (composite powder).

[0017] The composite may comprise metal powder and a resin composition adhering to the surface of each metal particle constituting the metal powder. The resin composition may cover the entire surface of the particles or only a portion of the particle surface. The composite may also comprise an uncured resin composition and metal powder. The composite may also comprise a semi-cured resin composition (e.g., a B-stage resin composition) and metal powder. The composite may also comprise both an uncured resin composition and a semi-cured resin composition. The composite may also be formed from metal powder and a resin composition.

[0018] The content of metal powder in the composite can be 90% by mass or more and less than 100% by mass relative to the total mass of the composite. If the content of metal powder increases, it becomes difficult to ensure the demolding properties of the molded article, and the workability tends to deteriorate. From the viewpoint of the magnetic properties of the molded article, the content of metal powder is preferably 92% by mass or more, more preferably 94% by mass or more, further preferably 95% by mass or more, and particularly preferably 96% by mass or more. The upper limit of the metal powder content can be 99% by mass or less, 98% by mass or less, or 97.5% by mass or less.

[0019] (Resin Composition)

[0020] The resin composition functions as a binding material (binder) for the metal particles constituting the metal powder, imparting mechanical strength to the molded article formed from the composite. For example, when the composite is molded under high pressure using a mold, the resin composition contained in the composite is filled between the metal particles, causing the particles to adhere to each other. By curing the resin composition in the molded article, the cured resin composition further strengthens the adhesion between the metal particles, thereby improving the mechanical strength of the molded article.

[0021] The resin composition of this embodiment improves the flowability of the composite by containing an epoxy resin as a thermosetting resin. The epoxy resin can be, for example, a resin having two or more epoxy groups in one molecule. The type of epoxy resin is not particularly limited and can be selected according to the desired properties of the composition.

[0022] Examples of epoxy resins include: biphenyl-type epoxy resins, piracene-type epoxy resins, diphenylmethane-type epoxy resins, sulfur-containing epoxy resins, phenolic varnish-type epoxy resins, dicyclopentadiene-type epoxy resins, salicylaldehyde-type epoxy resins, copolymer epoxy resins of naphthols and phenols, epoxides of aralkyl-type phenolic resins, bisphenol-type epoxy resins, epoxy resins containing a bisphenol backbone, epoxy propyl ether-type epoxy resins of alcohols, epoxy propyl ether-type epoxy resins modified with p-xylene and / or m-xylene, and terpene-modified phenolic resins. The epoxy resins include epoxypropyl ether type epoxy resins, cyclopentadiene type epoxy resins, epoxypropyl ether type epoxy resins of polycyclic aromatic ring modified phenolic resins, epoxypropyl ether type epoxy resins of phenolic resins containing naphthalene rings, epoxypropyl ester type epoxy resins, epoxypropyl type or methylepoxypropyl type epoxy resins, alicyclic epoxy resins, halogenated phenolic varnish type epoxy resins, o-cresol phenolic varnish type epoxy resins, hydroquinone type epoxy resins, trimethylolpropane type epoxy resins, and linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid.

[0023] From a flowability perspective, epoxy resin may include at least one selected from the group consisting of biphenyl-type epoxy resin, o-cresol phenolic varnish-type epoxy resin, phenolic varnish-type epoxy resin, bisphenol-type epoxy resin, epoxy resin having a bisphenol backbone, salicylaldehyde phenolic varnish-type epoxy resin, and naphthol phenolic varnish-type epoxy resin.

[0024] From the viewpoint of mechanical strength, epoxy resin may include at least one selected from the group consisting of biphenyl aralkyl type epoxy resin and o-cresol phenolic varnish type epoxy resin.

[0025] Epoxy resins can be crystalline epoxy resins. Although crystalline epoxy resins have a relatively low molecular weight, they have a relatively high melting point and excellent flowability. Crystalline epoxy resins (highly crystalline epoxy resins) may, for example, include 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.

[0026] 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-7200HHH, EPICLON HP-7200HHH, EPICLON HP-4700, and EPICLON... HP-4710, EPICLON HP-4770, EPICLON HP-5000, EPICLON HP-6000, N500P-2 and N500P-10 (these are trade names manufactured by DICCorporation); 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 and BREN-10S (these are trade names manufactured by Nippon Kayaku). Trade names manufactured by Co., Ltd.; YX-4000, YX-4000H, YL4121H and YX-8800 (the above are trade names manufactured by Mitsubishi Chemical Corporation).

[0027] The resin composition may contain one of the epoxy resins described above. The resin composition may also contain multiple epoxy resins described above. Among the epoxy resins described above, the resin composition may also contain an epoxy resin comprising a biphenyl backbone, an o-cresphenolic varnish-type epoxy resin, or a multifunctional epoxy resin containing two or more epoxy groups.

[0028] Curing agents are classified into curing agents that cure epoxy resins in a range from low temperature to room temperature, and heat-curing curing agents that cure epoxy resins with heat. Examples of curing agents that cure epoxy resins in a range from low temperature to room temperature include aliphatic polyamines, polyaminoamides, and polythiols. Examples of heat-curing curing agents include aromatic polyamines, acid anhydrides, phenolic varnish resins, and dicyandiamine (DICY). The type of curing agent is not particularly limited and can be selected based on the desired properties of the composition.

[0029] When a curing agent that cures epoxy resin in a range from low temperature to room temperature is used, the cured epoxy resin tends to have a low glass transition point and be soft. As a result, the molded body formed from the composite also tends to become soft. On the other hand, from the viewpoint of improving the heat resistance of the molded body, the curing agent can preferably be a heat-curing type, more preferably a phenolic resin, and even more preferably a phenolic varnish resin. In particular, by using a phenolic varnish resin as a curing agent, it is easy to obtain a cured epoxy resin with a high glass transition point. As a result, the heat resistance and mechanical strength of the molded body are easily improved.

[0030] Phenolic resins may include, for example, at least one selected from the group consisting of aryl phenolic resins, dicyclopentadiene phenolic resins, salicylaldehyde phenolic resins, phenolic varnish phenolic resins, copolymers of benzaldehyde-type phenols and aryl phenols, p-xylene and / or m-xylene-modified 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. Phenolic resins may also be copolymers composed of two or more of the above. Commercially available phenolic resins include, for example, Tamanol 758 manufactured by Arakawa Chemicai Industries, Ltd., or HP-850N manufactured by Hitachi Chemical Co., Ltd.

[0031] Phenolic varnish resins can be, for example, resins obtained by condensing or co-condensing phenols and / or naphthols with aldehydes under an acidic catalyst. The phenols constituting the phenolic varnish resin may include, 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 phenolic varnish resin may include, for example, at least one selected from the group consisting of α-naphthol, β-naphthol, and dihydroxynaphthalene. The aldehydes constituting the phenolic varnish resin may include, for example, at least one selected from the group consisting of formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and salicylaldehyde.

[0032] The curing agent may, for example, be a compound having two phenolic hydroxyl groups in one molecule. A compound having two phenolic hydroxyl groups in one molecule may, for example, comprise at least one selected from the group consisting of resorcinol, catechol, bisphenol A, bisphenol F, and substituted or unsubstituted biphenols.

[0033] The resin composition may contain one of the phenolic resins described above. The resin composition may also contain multiple phenolic resins described above. The resin composition may contain one of the curing agents described above. The resin composition may also contain multiple curing agents described above.

[0034] The ratio of active groups (phenolic OH groups) in the curing agent that react with the epoxy groups in the epoxy resin is preferably 0.5 to 1.5 equivalents, more preferably 0.6 to 1.4 equivalents, and even more preferably 0.7 to 1.2 equivalents, relative to 1 equivalent of epoxy groups in the epoxy resin. When the ratio of active groups in the curing agent is less than 0.5 equivalents, it is difficult to obtain a sufficient elastic modulus in the cured product. On the other hand, when the ratio of active groups in the curing agent exceeds 1.5 equivalents, there is a tendency for the mechanical strength of the molded article formed by the composite to decrease after curing. However, even when the ratio of active groups in the curing agent is outside the above range, the effects of the present invention can be obtained.

[0035] Coupling agents can improve the adhesion between the resin composition and the metal-containing particles constituting the metal powder, thereby improving the flexibility and mechanical strength of the molded article formed from the composite. The resin composition of this embodiment can improve the flowability and curing properties of the composite by containing a specific silane compound as a coupling agent. The coupling agent comprises a first silane compound and a second silane compound, the first silane compound having a functional group selected from epoxy, amino, urea, and isocyanate groups, and the second silane compound having a chain hydrocarbon group having 6 or more carbon atoms. In this specification, a chain hydrocarbon group having 6 or more carbon atoms is sometimes referred to as a long-chain hydrocarbon group.

[0036] By including a first silane compound in the resin composition, a molded body with excellent high-temperature bending properties can be formed. The functional groups of the first silane compound can react with epoxy resin or curing agent. The first silane compound is a silane compound without long-chain hydrocarbon groups.

[0037] Examples of first silane compounds having an epoxy group include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, and 3-epoxypropoxypropyltriethoxysilane.

[0038] Examples of first silane compounds having an amino group include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldiethoxysilane, N-phenyl-3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropylmethyldiethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane.

[0039] Examples of first silane compounds having a urea group include 3-ureopropyltrimethoxysilane, 3-ureopropyltriethoxysilane, 3-ureopropylmethyldimethoxysilane, and 3-ureopropylmethyldiethoxysilane.

[0040] Examples of first silane compounds having an isocyanate group include 3-isocyanate propyltrimethoxysilane, 3-isocyanate propyltriethoxysilane, 3-isocyanate propylmethyldimethoxysilane, and 3-isocyanate propylmethyldiethoxysilane.

[0041] From the viewpoint of further improving high-temperature bending properties, the content of the first silane compound relative to 100 parts by weight of epoxy resin can be 0.5 parts by weight or more and 10 parts by weight or less, 1.0 parts by weight or more and 8.0 parts by weight or more and 7.0 parts by weight or less.

[0042] By including a second silane compound in the resin composition, the flowability of the composite during molding can be improved. The second silane compound has a chain hydrocarbon group with 6 or more carbon atoms, which can be 7 or more or 8 or more, and can be 20 or less, 16 or less, or 14 or less. The second silane compound can have a styrene group, a (meth)acryloyl group, or a vinyl group.

[0043] Examples of second silane compounds include hexyltrimethoxysilane, hexyltriethoxysilane, heptyltrimethoxysilane, heptyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, acryloyloxyhexyltrimethoxysilane, acryloyloxyhexyltriethoxysilane, methacryloyloxyhexyltrimethoxysilane, methacryloyloxyhexyltriethoxysilane, acryloyloxyheptyltrimethoxysilane, acryloyloxyheptyltrimethoxysilane, acryloyloxyheptyltriethoxysilane, methacryloyloxyheptyltrimethoxysilane, methacryloyloxyheptyltriethoxysilane, methacryloyloxyheptyltrimethoxysilane, methacryloyloxyheptyltriethoxysilane, acryloyloxyoctyltrimethoxysilane, acryloyloxyoctyltriethoxysilane, and methacryloyloxyoctyltriethoxysilane.

[0044] From the viewpoint of further improving fluidity, the content of the second silane compound relative to 100 parts by weight of epoxy resin can be 0.1 parts by weight or more and 5.0 parts by weight or less, 0.5 parts by weight or more and 4.0 parts by weight or more and 1.0 parts by weight or less and 3.0 parts by weight or less.

[0045] The coupling agent may further comprise a third silane compound having a thiol group. The third silane compound is a silane compound that does not have a long-chain hydrocarbon group. Examples of third silane compounds include, for example, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropylmethyldiethoxysilane.

[0046] From the perspective of balancing flowability and mechanical properties, the content of coupling agent relative to 100 parts by weight of epoxy resin can be more than 1.0 parts by weight and less than 20 parts by weight, more than 2.0 parts by weight and less than 15 parts by weight, or more than 3.0 parts by weight and less than 10 parts by weight.

[0047] Curing accelerators are not limited to any composition that promotes the curing of epoxy resin in reaction with epoxy resin. Examples of curing accelerators include phosphorus-based, imidazole-based, or urea-based curing accelerators. By including a curing accelerator in the resin composition, the formability and release properties of the composite can be improved. Furthermore, by including a curing accelerator in the resin composition, the mechanical strength of molded articles (e.g., electronic components) manufactured using the composite is improved, or the storage stability of the composite under high temperature / high humidity conditions is improved.

[0048] Phosphorus-based curing accelerators include, for example, phosphine compounds and phosphonium salt compounds.

[0049] Commercially available imidazole-based curing accelerators may include, 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 (the above are trade names manufactured by Shikoku Chemicals Corporation).

[0050] As a urea-based curing accelerator, there is no particular limitation as long as it contains a urea group; however, from the viewpoint of improving storage stability, alkylurea-based curing accelerators containing alkylurea groups are preferred. Examples of alkylurea-based curing accelerators containing alkylurea groups include aromatic alkylureas and aliphatic alkylureas. Commercially available alkylurea-based curing accelerators include, for example, U-CAT3512T (trade name, manufactured by San-Apro Ltd., aromatic dimethylurea) and U-CAT3513N (trade name, manufactured by San-Apro Ltd., aliphatic dimethylurea). Among these, aromatic alkylureas are preferred because their pyrolysis temperature is appropriately low, facilitating efficient curing of the complex.

[0051] The amount of curing accelerator is not particularly limited, as long as it is sufficient to achieve the curing-promoting effect. From the viewpoint of improving the curing properties and flowability of the resin composition when it is hygroscopic, the amount of curing accelerator relative to 100 parts by weight of epoxy resin is preferably 0.1 parts by weight or more and 30 parts by weight or less, more preferably 0.5 parts by weight or more and 15 parts by weight or less, and even more preferably 1.0 parts by weight or more and 10 parts by weight or less. When the amount of curing accelerator is 0.1 parts by weight or more, a sufficient curing-promoting effect can be easily obtained. If the amount of curing accelerator is 30 parts by weight or less, the storage stability of the composite is less likely to decrease. The content of curing accelerator relative to 100 parts by weight of the total mass of epoxy resin and phenolic resin is preferably 0.001 parts by weight or more and 5 parts by weight or less. However, even when the amount and content of curing accelerator are outside the above ranges, the effects of the present invention can still be obtained.

[0052] Resin compositions can contain compounds with siloxane bonds (siloxane compounds) as additives because the molding shrinkage of the composite is easily reduced, and the heat resistance and voltage resistance of the molded article are easily improved. A siloxane bond is a bond containing two silicon atoms (Si) and one oxygen atom (O), and can be represented by -Si-O-Si-. Compounds with siloxane bonds can be polysiloxane compounds.

[0053] The content of siloxane compounds can be more than 1 part by mass and less than 50 parts by mass, more than 5 parts by mass and less than 45 parts by mass, or more than 10 parts by mass and less than 40 parts by mass relative to 100 parts by mass of epoxy resin.

[0054] To ensure the environmental safety, recyclability, processability, and low cost of the composite, the composite may contain a flame retardant. The flame retardant may be, for example, at least one selected from the group consisting of brominated flame retardants, phosphorus-based flame retardants, hydrated metal compound flame retardants, silicone-based flame retardants, nitrogen-containing compounds, hindered amine compounds, organometallic compounds, and aromatic engineering plastics. The resin composition may contain one or more of the above-mentioned flame retardants.

[0055] When a mold is used to form a molded body from the composite, the resin composition may contain wax. The wax improves the flowability of the composite during molding (e.g., transfer molding) and acts as a release agent. The wax can be at least one of fatty acids, such as higher fatty acids, and fatty acid esters.

[0056] The wax may be, for example, at least one selected from the group consisting of: fatty acids such as linalic acid, stearic acid, 12-hydroxystearic acid, and lauric acid, or esters thereof; fatty acid salts such as zinc stearate, calcium stearate, barium stearate, aluminum stearate, magnesium stearate, calcium laurate, zinc laurate, zinc linoleate, calcium ricinoleate, and zinc 2-ethylhexanoate; stearamide, oleamide, erucamide, betaine amide, palmitamide, laurate amide, hydroxystearamide, methylene bis-stearamide, ethylene bis-stearamide, ethylene bis-laurate amide, distearate adipamide, ethylene dioleate amide, dioleenyl adipamide, N-stearate... Fatty acid amides such as oleyl stearamide, N-oleyl stearamide, N-stearyl erucamide, hydroxymethyl stearamide, and hydroxymethyl benzyl amide; fatty acid esters such as butyl stearate; alcohols such as ethylene glycol and stearyl alcohol; polyethers including polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and their modified forms; polysiloxanes such as silicone oil and silicone grease; fluorinated compounds such as fluorinated oils, fluorinated greases, and fluorinated resin powders; and waxes such as paraffin wax, polyethylene wax, amide wax, polypropylene wax, ester wax, carnauba wax, and microcrystalline wax.

[0057] From the perspective of balancing flowability and release properties, the wax content can be more than 1 part by weight and less than 20 parts by weight, more than 2 parts by weight and less than 15 parts by weight, or more than 3 parts by weight and less than 10 parts by weight, relative to 100 parts by weight of epoxy resin.

[0058] (Metallic powder)

[0059] Metal powder (particles containing a metallic element) may contain at least one element selected from the group consisting of metallic monomers, alloys, and metallic compounds. Alloys may contain at least one element selected from the group consisting of solid solutions, eutectics, and intermetallic compounds. Alloys may be, for example, stainless steel (Fe-Cr alloys, Fe-Ni-Cr alloys, etc.). Metal compounds may be, for example, oxides such as ferrophosphate. Metal powder may contain one or more metallic elements. The metallic elements contained in the metal powder may be, for example, base metals, noble metals, transition metals, or rare earth elements. A composite may contain one metallic element powder or multiple metallic element powders with different compositions.

[0060] The metallic element contained in the metal powder may be 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), niobium (Nb), barium (Ba), strontium (Sr), lead (Pb), silver (Ag), praseodymium (Pr), neodymium (Nd), samarium (Sm), and dysprosium (Dy). From the viewpoint of improving magnetic properties, the metal powder preferably contains at least one metallic element selected from the group consisting of iron, cobalt, and nickel. The metal powder may further contain elements other than metallic elements. For example, the metal powder may contain carbon (C), oxygen (O), beryllium (Be), phosphorus (P), sulfur (S), boron (B), or silicon (Si).

[0061] The metal powder can be magnetic powder. It can also be a soft magnetic alloy or a strong magnetic alloy. For example, the metal powder can be a magnetic powder selected from at least one of the following groups: Fe-Si alloys, Fe-Si-Al alloys (Aluminum-Silicon-Iron Powder (Sendust)), Fe-Ni alloys (High Permeability Alloy (Permalloy)), Fe-Cu-Ni alloys (High Permeability Alloy), Fe-Co alloys (Iron-Co Alloy (Permendur)), Fe-Cr-Si alloys (Electromagnetic Stainless Steel), Nd-Fe-B alloys (Rare Earth Magnets), Sm-Fe-N alloys (Rare Earth Magnets), Al-Ni-Co alloys (Alnico Magnets), and granulated iron. Granulated iron can be, for example, spinel granulated iron, hexagonal granulated iron, or garnet granulated iron. The metal powder can also be a copper alloy such as Cu-Sn alloys, Cu-Sn-P alloys, Cu-Ni alloys, or Cu-Be alloys. The metal powder may contain one or more of the above-mentioned elements and compositions.

[0062] The metal powder can also be Fe monomer. The metal powder can also be an iron-containing alloy (Fe-based alloy). Fe-based alloys can be, for example, Fe-Si-Cr alloys or Nd-Fe-B alloys. The metal-containing powder can also be at least one of amorphous iron powder and carbonyl iron powder. When the metal powder contains at least one of Fe monomer and Fe-based alloy, it is easy to fabricate a shaped body with a high space factor and excellent magnetic properties from the composite. The metal powder can also be an amorphous Fe alloy.

[0063] As a commercially available Fe amorphous alloy powder, for example, at least one of the following can be used: AW2-08, KUAMET-6B2 (trade names manufactured by Epson Atmix Corporation), DAP MS3, DAP MS7, DAP MSA10, DAP PB, DAP PC, DAP MKV49, DAP 410L, DAP 430L, DAP HYB series (trade names manufactured by Daido Steel Co., Ltd.), MH45D, MH28D, MH25D and MH20D (trade names manufactured by Kobe Steel, Ltd.).

[0064] <Method for manufacturing the complex>

[0065] In the manufacture of the composite, metal powder and resin composition (the components constituting the resin composition) are mixed while heated. For example, the metal powder and resin composition are mixed while heated using a kneader, roller, mixer, etc. Through heating and mixing of the metal powder and resin composition, the resin composition adheres to part or all of the surface of the metal-containing particles constituting the metal powder, thus coating the metal-containing particles, thereby partially or completely solidifying the epoxy resin in the resin composition. As a result, a composite is obtained. A composite can also be obtained by further adding wax to the powder obtained by heating and mixing the metal powder and resin composition. Alternatively, the resin composition and wax can be pre-mixed.

[0066] In the mixing process, metal powder, epoxy resin, curing agent, curing accelerator, and coupling agent can be mixed in a tank. Alternatively, after mixing the metal powder and coupling agent in the tank, the epoxy resin, curing agent, and curing accelerator can be added to the tank for mixing. Alternatively, the siloxane compound, epoxy resin, curing agent, and coupling agent can be mixed in the tank, and then the curing accelerator can be added to the tank for mixing. Alternatively, a mixed powder of epoxy resin, curing agent, and curing accelerator (resin mixed powder) can be prepared in advance, and then the metal powder and coupling agent can be mixed to produce a metal mixed powder, which is then mixed with the aforementioned resin mixed powder.

[0067] The mixing time also depends on the type of mixing machinery, the volume of the mixing machinery, and the amount of compound produced. For example, it is preferably 1 minute or more, more preferably 2 minutes or more, and even more preferably 3 minutes or more. Furthermore, the mixing time is preferably 20 minutes or less, more preferably 15 minutes or less, and even more preferably 10 minutes or less. When the mixing time is less than 1 minute, the mixing is insufficient, which impairs the formability of the compound, and the degree of curing of the compound deviates. When the mixing time exceeds 20 minutes, for example, curing of the resin composition (e.g., epoxy resin and phenolic resin) in a tank can easily impair the flowability and formability of the compound.

[0068] When the raw materials in the tank are heated and kneaded using a kneader, the heating temperature is, for example, a temperature that produces a semi-cured epoxy resin (stage B epoxy resin) and inhibits the formation of a cured epoxy resin (stage C epoxy resin). The heating temperature can also be lower than the activation temperature of the curing accelerator. The heating temperature is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 70°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-containing particles constituting the metal powder, thereby easily producing a semi-cured epoxy resin and easily inhibiting the complete curing of the epoxy resin during kneading.

[0069] [molded body]

[0070] The molded article of this embodiment may include the above-described composite. The molded article of this embodiment may also include a cured product of the above-described composite. The molded article may contain at least one selected from the group consisting of an uncured resin composition, a semi-cured resin composition (resin composition of stage B), and a cured resin composition (resin composition of stage C). The molded article of this embodiment can be used as a sealing material for electronic components or electronic circuit boards. According to this embodiment, cracks in the molded article caused by the difference in thermal expansion coefficients between the metal parts of the electronic component or electronic circuit board and the molded article (sealing material) can be suppressed.

[0071] The cured product of the composite is a cured product of a metal powder and resin composition, wherein the metal powder content is 90% by mass or more and less than 100% by mass. From the viewpoint of improving the strength of the cured product, the flexural strength of the cured product at 250°C is preferably 7.0 MPa or more, more preferably 8.0 MPa or more, and even more preferably 8.5 MPa or more. The upper limit of the flexural strength is about 10 MPa. From the viewpoint of imparting flexibility to the cured product, the flexural modulus of elasticity of the cured product at 250°C can be 1.3 GPa or less, 1.2 GPa or less, or 1.1 GPa or less. The lower limit of the flexural modulus of elasticity is about 0.1 GPa. The value obtained by dividing the flexural strength (MPa) at 250°C by the flexural modulus of elasticity (GPa) at 250°C can be used as a reliability index of the cured product. This index is preferably 9.0 × 10⁻⁶. -3 The above is preferred, with 9.2×10 being more desirable. -3 The above is further optimized to be 10.4 × 10 -3 That's all. The upper limit for this indicator is not specifically limited; for example, it could be 5 × 10. -2 the following.

[0072] <Manufacturing Method of Molded Body>

[0073] The method for manufacturing a molded article according to this embodiment may include a step of pressing the composite material in a mold. The method may also include a step of pressing a portion or all of the composite material covering the surface of a metal part in a mold. The method may only include the step of pressing the composite material in a mold, or it may include other steps besides this step. The method may also include a first step, a second step, and a third step. The details of each step will be described below.

[0074] In the first step, the composite is prepared using the method described above.

[0075] In the second step, a molded article (the molded article of stage B) is obtained by pressing the composite in a mold. In the second step, a molded article (the molded article of stage B) can be obtained by pressing a portion or all of the composite covering the surface of the metal part in a mold. In the second step, a resin composition is filled between the individual metal-containing particles constituting the metal-containing powder. Furthermore, the resin composition acts as a binding material (adhesive), bonding the metal-containing particles together.

[0076] As a second step, transfer molding of the compound can also be performed. In transfer molding, the compound can be pressurized at a pressure of 5 MPa or more and 50 MPa or less. The higher the molding pressure, the easier it is to obtain a molded body with excellent mechanical strength. Considering the mass production of the molded body and the life of the mold, the molding pressure is preferably 8 MPa or more and 20 MPa or less. The density of the molded body formed by transfer molding is preferably 75% or more and 86% or less, more preferably 80% or more and 86% or less, relative to the true density of the compound. When the density of the molded body is 75% or more and 86% or less, it is easier to obtain a molded body with excellent mechanical strength. In transfer molding, the second and third steps can also be performed collectively.

[0077] In the third step, the molded body is cured by heat treatment to obtain the C-stage molded body. The heat treatment temperature only needs to be the temperature at which the resin composition in the molded body is fully cured. The heat treatment temperature is preferably 100°C or higher and 300°C or lower, more preferably 110°C or higher and 250°C or lower. In order to suppress the oxidation of metal powder in the molded body, it is preferable to perform heat treatment in an inert atmosphere. When the heat treatment temperature exceeds 300°C, the metal powder is oxidized or the cured resin is deteriorated due to the trace amount of oxygen inevitably contained in the heat treatment atmosphere. In order to suppress the oxidation of metal powder and the deterioration of the cured resin and to fully cure the resin composition, the holding time of the heat treatment temperature is preferably a few minutes or more and 10 hours or less, more preferably 3 minutes or more and 8 hours or less.

[0078] Example

[0079] The present invention will be further described in detail below through examples and comparative examples, but the present invention is not limited to these examples in any way.

[0080] The following details the components used in the preparation of the complexes in the examples and comparative examples.

[0081] (Epoxy resin)

[0082] Biphenylaryl type epoxy resin (trade name: NC-3000, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 275g / eq)

[0083] Multifunctional epoxy resin (trade name: TECHMORE VG3101L, manufactured by Printec Corporation, epoxy equivalent: 215g / eq)

[0084] (Curing agent)

[0085] Triphenylmethane-type phenolic resin (trade name: HE910-09 manufactured by AIR WATER INC., hydroxyl equivalent: 101 g / eq)

[0086] Biphenylaryl phenolic resin (manufactured by Meiwa Plastic Industries, Ltd., trade name: MEHC-7841-4S, hydroxyl equivalent: 166 g / eq)

[0087] (Coupled agent)

[0088] 3-Epoxypropoxypropyltrimethoxysilane (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0089] 3-Mercaptopropyltrimethoxysilane (trade name: KBM-803, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0090] Methacryloxyoctyltrimethoxysilane (trade name: KBM-5803, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0091] (Curing accelerator)

[0092] Imidazole-based curing accelerator (trade name: 2P4MHZ-PW, manufactured by Shikoku Chemicals Corporation)

[0093] (Mold release agent)

[0094] Zinc lauryl sulfate (manufactured by NOF CORPORATION, trade name: Powder Base L)

[0095] Partially saponified lignite ester wax (manufactured by Clariant Chemicals Co., Ltd., trade name: Licowax-OP)

[0096] (additive)

[0097] Caprolactone-modified dimethyl silicone (trade name: DBL-C32, manufactured by Gelest, Inc.)

[0098] (Metallic powder)

[0099] Amorphous iron powder (trade name: 9A4-II, manufactured by Epson Atmix Corporation, average particle size 24μm)

[0100] Amorphous iron powder (trade name: AW2-08 manufactured by Epson Atmix Corporation, average particle size 5.3μm)

[0101] [Preparation of the complex]

[0102] (Examples 1-5)

[0103] The epoxy resin, curing agent, curing accelerator, and release agent shown in Table 1 were added to a plastic container at the amounts (in grams) indicated in the table. A resin mixture was prepared by mixing these materials in the plastic container for 10 minutes. The resin mixture represents all components of the resin composition except for the coupling agent and additives.

[0104] Metal powder was prepared by uniformly mixing the two amorphous iron powders shown in Table 1 for 5 minutes in a pressure biaxial kneader (manufactured by Nihon Spindle Manufacturing Co., Ltd., capacity 5L). The coupling agent and additives shown in Table 1 were added to the metal powder in the biaxial kneader. The contents of the biaxial kneader were then heated to 90°C and mixed for 10 minutes while maintaining this temperature. The resin mixture was then added to the contents of the biaxial kneader, and the contents were melted / kneaded for 15 minutes while maintaining the temperature at 120°C. The resulting mixture was cooled to room temperature and then pulverized with a hammer to achieve the specified particle size. Note that "melting" refers to the melting of at least a portion of the resin composition in the contents of the biaxial kneader. The metal powder in the composite did not melt during composite preparation. The composites of Examples 1-5 were prepared using the above method.

[0105] (Comparative Examples 1-3)

[0106] Except for changing the types and amounts of each component as shown in Table 2, the complexes of Comparative Examples 1 to 3 were prepared by operating in the same manner as in the Examples.

[0107] [Evaluation of the complex]

[0108] The complexes obtained in the examples and comparative examples were evaluated as follows. The results are shown in Tables 1 and 2.

[0109] (Liquidity)

[0110] Flowability was evaluated using a Shimadzu Corporation Flowtester CFT-100. 7g of the complex was formed into tablets. Flowability was evaluated using the tablets under conditions of 130°C, residual heat for 20 seconds, and a load of 100kg. The plunger's insertion distance (in mm) before the complex stopped flowing was defined as the flow tester stroke, and the time until the complex stopped flowing was measured as the flow time, which was used as an indicator of flowability.

[0111] (gelation time)

[0112] The gelation time of the composite was determined using the following method. A vulcanizer (manufactured by JSR Trading Co., Ltd.) was used to determine the gelation time at 140°C with a sample volume of 1.5 mL. The onset time of torque rise in the obtained graph was taken as the gelation time. A shorter gelation time indicates higher curability.

[0113] (Bending test)

[0114] The composite was transferred and molded under conditions of 140℃ mold temperature, 13.5MPa molding pressure, and 360 seconds curing time, and then post-cured at 180℃ for 2 hours to obtain the test piece. The dimensions of the test piece were 80mm in width × 10mm in width × 3.0mm in thickness.

[0115] A three-point supported bending test was conducted on the test specimen at 250°C using an automated stereographic plotter equipped with a thermostatic bath. The automated stereographic plotter was an AGS-500A manufactured by Shimadzu Corporation. In the bending test, one face of the test specimen was supported by two supports. A load was applied at the center between the two supports on the other face of the test specimen. The load at which the test specimen failed was measured. The bending test conditions are as follows.

[0116] The distance Lv between the two support points: 64.0 ± 0.5 mm

[0117] Head speed: 2.0 ± 0.2 mm / min

[0118] Chart speed: 100mm / minute

[0119] Chart full scale: 490N (50kgf)

[0120] Calculate the flexural strength σ (unit: MPa) using formula (A) below. Calculate the flexural modulus E (unit: GPa) using formula (B) below. In the following formulas, “P” is the load (unit: N) at which the test specimen fails. “Lv” is the distance between the two support points (unit: mm). “W” is the width of the test specimen (unit: mm). “t” is the thickness of the test specimen (unit: mm). “F / Y” is the slope of the linear portion of the load-deflection curve (unit: N / mm).

[0121] σ=(3×P×Lv) / (2×W×t 2 (A)

[0122] E = [Lv] 3 / (4×W×t 3 )]×(F / Y) (B)

[0123] (reliability)

[0124] The value obtained by dividing the flexural strength (MPa) at 250℃ by the flexural modulus of elasticity (GPa) at 250℃ is used as an evaluation index for reliability. The larger the value, the better the balance between strength and modulus of elasticity.

[0125] (Reflow processing)

[0126] By transfer forming, copper metal parts are sealed with a composite material, and the composite material is then cured to obtain a molded body. The molded body is then subjected to reflow treatment. The maximum heating temperature during reflow treatment is 260°C, and the heating time is 300 seconds. After reflow treatment, the molded body is observed, and the presence of cracks is investigated. In the table, "A" indicates that no cracks have formed in the molded body, and "B" indicates that cracks have formed in the molded body.

[0127] [Table 1]

[0128]

[0129] [Table 2]

[0130]

Claims

1. A composite comprising a metal powder and a resin composition containing an epoxy resin, a curing agent, and a coupling agent. The coupling agent comprises a first silane compound, a second silane compound, and a third silane compound, wherein the first silane compound has an epoxy, amino, urea, or isocyanate group; the second silane compound has a chain hydrocarbon group having 6 or more carbon atoms and has a styrene, (meth)acryloyl, or vinyl group; and the third silane compound has a mercapto group. The content of the metal powder is 90% by mass or more and less than 100% by mass. Relative to 100 parts by weight of the epoxy resin, the content of the first silane compound is 1.0 parts by weight or more and 8.0 parts by weight or less. The content of the second silane compound is 0.5 parts by mass or more and 4.0 parts by mass or less, relative to 100 parts by mass of the epoxy resin.

2. The complex according to claim 1, wherein, The first silane compound has an epoxy group.

3. The complex according to claim 1 or 2, wherein, The content of the coupling agent is 2.0 parts by weight or more and 15 parts by weight or less, relative to 100 parts by weight of the epoxy resin.

4. The complex according to claim 1 or 2, wherein, The metal powder contains at least one metallic element selected from the group consisting of iron, cobalt, and nickel.

5. The complex according to claim 1 or 2, wherein, The metal powder is magnetic powder.

6. A molded article comprising the composite of any one of claims 1 to 5.

7. A cured product, which is a cured product of the composite of any one of claims 1 to 5.

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