JP2022149538A - Compound, molding, and cured product of compound - Google Patents

Abstract

To provide a compound which enables formation of a molding that is excellent in a balance between a strength and elastic modulus under high temperature and is excellent in voltage resistance, a molding using the compound, and a cured product of the compound.SOLUTION: A compound contains resin composition contains metal powder, and a resin composition containing an epoxy resin, a curing agent and a coupling agent, wherein the coupling agent contains a polyfunctional silane compound having kinematic viscosity at 25°C of 10-2,000 mm2/s.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a compound, a molded article, and a cured product of the compound.

A compound containing a metal powder and a resin composition is used as a raw material for various industrial products depending on the physical properties of the metal powder. For example, compounds are used as raw materials for inductors, sealing materials, electromagnetic wave shields (EMI shields), bond magnets, and the like (see Patent Document 1 below).

Japanese Unexamined Patent Application Publication No. 2014-13803

When an industrial product is manufactured from a compound, the compound and a metal member are brought into close contact with each other, and the compound is cured to produce a molded body, and then the molded body is sometimes heated. Molded articles are required to have an excellent balance between strength and elastic modulus at high temperatures and to improve reliability. Industrial products such as inductors are sometimes required to withstand voltage.

The present invention provides a compound capable of forming a molded article having an excellent balance between strength and elastic modulus at high temperatures and excellent voltage resistance, a molded article using the compound, and a cured product of the compound. With the goal.

A compound according to one aspect of the present invention comprises a metal powder, an epoxy resin, a curing agent, and a resin composition containing a coupling agent, and the coupling agent has a kinematic viscosity at 25° C. of 10 to 2000 mm ² /s containing a polyfunctional silane compound.

A molded article according to one aspect of the present invention includes the above compound. A cured product according to one aspect of the present invention is a cured product of the above compound.

According to the present invention, there are provided a compound capable of forming a molded article having excellent fluidity during molding and excellent mechanical properties at high temperatures, a molded article using the compound, and a cured product of the compound.

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

[compound]
The compound according to this embodiment includes metal powder and a resin composition. The metal powder may contain, for example, at least one selected from the group consisting of simple metals, 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 contains a polyfunctional silane compound having a kinematic viscosity of 10-2000 mm ² /s at 25°C. In the compound, metal powder, epoxy resin, hardener, and coupling agent are mixed. The resin composition may further contain curing accelerators, release agents, additives and the like as other components. The resin composition is a component that can include an epoxy resin, a curing agent, a coupling agent, a curing accelerator, a release agent, and additives, and the remaining components (non-volatile components) excluding the organic solvent and the metal powder ). Additives are components of the resin composition other than the resin, release agent, curing agent, curing accelerator, and coupling agent. Additives are, for example, flame retardants, lubricants, and the like. The compound may be a powder (compound powder).

The compound may comprise metal powder and a resin composition adhered to the surfaces of individual metal particles that make up the metal powder. The resin composition may cover the entire surface of the particle, or may cover only a part of the surface of the particle. The compound may comprise an uncured resin composition and metal powder. The compound may comprise a semi-cured resin composition (for example, a B-stage resin composition) and metal powder. The compound may comprise both an uncured resin composition and a semi-cured resin composition. The compound may consist of metal powder and a resin composition.

The content of the metal powder in the compound is preferably 90% by mass or more and less than 100% by mass with respect to the mass of the entire compound. When the content of the metal powder increases, it becomes difficult to ensure the releasability of the compact, and workability tends to be poor. From the viewpoint of the magnetic properties of the compact, the content of the metal powder is preferably 92% by mass or more, more preferably 94% by mass or more, and even more preferably 95% by mass or more. The upper limit of the metal powder content may be 99% by mass or less, 98% by mass or less, or 97.5% by mass or less.

(resin composition)
The resin composition functions as a binding material (binder) for the metal particles that make up the metal powder, and imparts mechanical strength to the compact formed from the compound. For example, the resin composition contained in the compound is filled between the metal particles and binds the particles together when the compound is molded at high pressure using a mold. By curing the resin composition in the molded article, the cured resin composition more strongly binds the metal particles together, improving the mechanical strength of the molded article.

The resin composition according to the present embodiment can improve the fluidity of the compound by containing an epoxy resin as a thermosetting resin. The epoxy resin may 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 resin composition.

Examples of epoxy resins include biphenyl-type epoxy resins, stilbene-type epoxy resins, diphenylmethane-type epoxy resins, sulfur atom-containing epoxy resins, novolak-type epoxy resins, dicyclopentadiene-type epoxy resins, salicylaldehyde-type epoxy resins, naphthols and phenols. Copolymerized epoxy resins, epoxidized aralkyl-type phenolic resins, bisphenol-type epoxy resins, epoxy resins containing a bisphenol skeleton, glycidyl ether-type epoxy resins of alcohols, glycidyl ethers of para-xylylene and/or meta-xylylene-modified phenolic resins type epoxy resin, terpene-modified phenol resin glycidyl ether type epoxy resin, cyclopentadiene type epoxy resin, polycyclic aromatic ring-modified phenol resin glycidyl ether type epoxy resin, naphthalene ring-containing phenol resin glycidyl ether type epoxy resin, glycidyl ester type Epoxy resins, glycidyl-type or methylglycidyl-type epoxy resins, alicyclic-type epoxy resins, halogenated phenol novolac-type epoxy resins, ortho-cresol novolak-type epoxy resins, hydroquinone-type epoxy resins, trimethylolpropane-type epoxy resins, and olefin bonds. Examples include linear aliphatic epoxy resins obtained by oxidation with peracids such as peracetic acid.

From the viewpoint of fluidity, epoxy resins include biphenyl-type epoxy resins, ortho-cresol novolac-type epoxy resins, phenol novolac-type epoxy resins, bisphenol-type epoxy resins, epoxy resins having a bisphenol skeleton, salicylaldehyde novolac-type epoxy resins, and naphthol novolak-type epoxy resins. It may contain at least one selected from the group consisting of type epoxy resins.

From the viewpoint of mechanical strength, the epoxy resin may contain at least one selected from the group consisting of biphenylene aralkyl-type epoxy resins and ortho-cresol novolak-type epoxy resins.

The epoxy resin may be a crystalline epoxy resin. Although the molecular weight of the crystalline epoxy resin is relatively low, the crystalline epoxy resin has a relatively high melting point and excellent fluidity. The crystalline epoxy resin (highly crystalline epoxy resin) may contain, for example, at least one selected from the group consisting of hydroquinone-type epoxy resins, bisphenol-type epoxy resins, thioether-type epoxy resins, and biphenyl-type epoxy resins. .

Commercially available crystalline epoxy resins include, for example, Epiclon 860, Epiclon 1050, Epiclon 1055, Epiclon 2050, Epiclon 3050, Epiclon 4050, Epiclon 7050, Epiclon HM-091, Epiclon HM-101, Epiclon N-730A, and 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, N500P-2, and N500P-10 (these are trade names manufactured by DIC Corporation); NC-3000, NC- 3000-L, NC-3000-H, NC-3100, CER-3000-L, NC-2000-L, XD-1000, NC-7000-L, NC-7300-L, EPPN-501H, EPPN-501HY, EPPN-502H, EOCN-1020, EOCN-102S, EOCN-103S, EOCN-104S, CER-1020, EPPN-201, BREN-S, and BREN-10S (trade names manufactured by Nippon Kayaku Co., Ltd.); YX-4000, YX-4000H, YL4121H, and YX-8800 (these are trade names manufactured by Mitsubishi Chemical Corporation).

The resin composition may contain one of the above epoxy resins. The resin composition may contain more than one type of epoxy resin among the above. Among the above epoxy resins, the resin composition may contain an epoxy resin containing a biphenyl skeleton, an ortho-cresol novolac-type epoxy resin, and a polyfunctional epoxy resin containing two or more epoxy groups.

Curing agents are classified into curing agents that cure epoxy resins in the range from low temperature to room temperature, and heat curing type curing agents that cure epoxy resins with heating. Curing agents that cure epoxy resins in the range from low temperature to room temperature include, for example, aliphatic polyamines, polyaminoamides, and polymercaptans. Heat-curable curing agents include, for example, aromatic polyamines, acid anhydrides, phenol novolac resins, and dicyandiamide (DICY). The type of curing agent is not particularly limited, and can be selected depending on the desired properties of the composition.

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

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

Phenol novolak resins may be resins obtained by, for example, condensation or co-condensation of phenols and/or naphthols and aldehydes under an acidic catalyst. Phenols constituting the phenolic novolak resin may 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 phenol novolak resin may contain, 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 contain at least one selected from the group consisting of formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde and salicylaldehyde, for example.

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

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

The ratio of the active group (phenolic OH group) in the curing agent that reacts with the epoxy group in the epoxy resin is preferably 0.5 to 1.5 equivalents, more preferably 1 equivalent of the epoxy group in the epoxy resin. may be 0.6 to 1.4 equivalents, more preferably 0.7 to 1.2 equivalents. If the ratio of active groups in the curing agent is less than 0.5 equivalents, it is difficult to obtain a cured product with a sufficient elastic modulus. On the other hand, if the ratio of the active groups in the curing agent exceeds 1.5 equivalents, the molded article formed from the compound tends to have reduced mechanical strength after curing. However, even if the ratio of active groups in the curing agent is outside the above range, the effects of the present invention can be obtained.

The coupling agent can improve the adhesion between the resin composition and the metal element-containing particles that make up the metal powder, and improve the flexibility and mechanical strength of the compact formed from the compound. The resin composition according to this embodiment contains, as a coupling agent, a polyfunctional silane compound having a kinematic viscosity at 25° C. of 10 to 2000 mm ² /s. By using a resin composition containing a specific silane compound, the curing properties of the compound are improved to form a molded article that not only has an excellent balance between strength and elastic modulus at high temperatures, but also has excellent voltage resistance. be able to.

As used herein, "polyfunctional silane compound" includes silane compounds having two or more alkoxysilyl groups and two or more reactive functional groups in one molecule, and "monofunctional silane compound" includes a silane compound having one alkoxysilyl group and one reactive functional group in one molecule. A "reactive functional group" does not include alkoxy groups. Alkoxy groups include, for example, methoxy, ethoxy, and propoxy groups. Reactive functional groups include, for example, (meth)acryloyl groups, vinyl groups, epoxy groups, amino groups, isocyanate groups, and mercapto groups.

The polyfunctional silane compound has at least one functional group selected from the group consisting of a (meth)acryloyl group, a vinyl group, an epoxy group, an amino group, an isocyanate group, and a mercapto group, from the viewpoint of further improving the curing properties of the compound. It may have two or more functional groups, and preferably has two or more functional groups of at least one type selected from the group consisting of (meth)acryloyl groups, epoxy groups, and mercapto groups. The number of functional groups possessed by the polyfunctional silane compound may be, for example, 2-10, 3-8, or 4-6. Polyfunctional silane compounds may be used singly or in combination.

The molecular weight of the polyfunctional silane compound may be 500 or more, 600 or more, or 800 or more, and may be 2500 or less, 2000 or less, 1800 or less, or 1500, from the viewpoint of further improving the balance between strength and elastic modulus at high temperatures. may be:

The kinematic viscosity at 25° C. of the polyfunctional silane compound may be 11 mm ² /s or more, 12 mm ² /s or more, or 13 mm ² /s or more, from the viewpoint of further improving voltage resistance, and is 1800 mm ² /s. 1700 mm ² /s or less, or 1600 mm ² /s or less. Kinematic viscosity can be measured using, for example, a rheometer according to JIS Z 8803:2011.

From the viewpoint of further improving the voltage resistance, the content of the polyfunctional silane compound may be 1.0 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the epoxy resin. It is preferably no greater than 1.5 parts by mass and no greater than 10 parts by mass, and even more preferably no less than 2.0 parts by mass and no greater than 7.0 parts by mass.

The coupling agent according to this embodiment may further contain a monofunctional silane compound. Examples of monofunctional silane compounds include silane compounds having a (meth)acryloyl group, vinyl group, epoxy group, amino group, isocyanate group, or mercapto group. A monofunctional silane compound may be, for example, a silane compound having a mercapto group. Silane coupling agents having a mercapto group include, for example, 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane.

From the viewpoint of further increasing the mechanical strength of the molded article, the content of the monofunctional silane compound is 0.1 parts by mass or more and 6.0 parts by mass or less, 0.5 parts by mass or more and 5 parts by mass with respect to 100 parts by mass of the epoxy resin. 0 mass parts or less, or 1.0 mass parts or more and 4.0 mass parts or less.

The resin composition may further contain a curing accelerator (catalyst) in order to improve moldability and releasability of the compound. By containing a curing accelerator in the resin composition, the mechanical strength of the molded article (e.g., electronic component) produced using the compound is improved, and the storage stability of the compound in a high-temperature and high-humidity environment. is improved. The curing accelerator is not particularly limited as long as it is a composition that reacts with the epoxy resin to accelerate curing of the epoxy resin. The curing accelerator may be, for example, a phosphorus curing accelerator, an imidazole curing accelerator, or a urea curing accelerator.

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

Commercially available imidazole curing accelerators include, for example, 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 Kasei Co., Ltd.).

The urea-based curing accelerator is not particularly limited as long as it is a curing accelerator having a urea group, but from the viewpoint of improving storage stability, it is preferably an alkylurea-based curing accelerator having an alkylurea group. Alkyl urea-based curing accelerators having an alkyl urea group include aromatic alkyl ureas and aliphatic alkyl ureas. Commercially available alkyl urea curing accelerators include, for example, U-CAT3512T (trade name, manufactured by San-Apro Co., Ltd., aromatic dimethyl urea) and U-CAT3513N (trade name, manufactured by San-Apro Co., Ltd., aliphatic dimethyl urea). mentioned. Among these, aromatic alkyl ureas are preferred because they have a moderately low cleavage temperature and facilitate efficient curing of compounds.

The amount of the hardening accelerator to be blended is not particularly limited as long as the hardening accelerating effect is obtained. From the viewpoint of improving the curability and fluidity of the resin composition when it absorbs moisture, the amount of the curing accelerator is 0.1 parts by mass or more and 20 parts by mass or less and 1 part by mass with respect to 100 parts by mass of the epoxy resin. 15 parts by mass or less, or 2 parts by mass or more and 10 parts by mass or less. When the amount of the curing accelerator is 0.1 parts by mass or more, a sufficient curing acceleration effect is likely to be obtained. When the amount of the curing accelerator is 30 parts by mass or less, the storage stability of the compound is less likely to deteriorate.

When forming a molding from a compound using a mold, the resin composition may contain wax. Wax enhances the fluidity of the compound in compound molding (for example, transfer molding) and functions as a release agent. The wax may be at least one of fatty acids such as higher fatty acids and fatty acid esters.

Waxes include fatty acids such as montanic acid, stearic acid, 12-oxystearic acid and lauric acid, or esters thereof; zinc stearate, calcium stearate, barium stearate, aluminum stearate, magnesium stearate, calcium laurate, Fatty acid salts such as zinc linoleate, calcium ricinoleate, and zinc 2-ethylhexoate; Acid amide, ethylenebisstearic acid amide, ethylenebislauric acid amide, distearyl adipic acid amide, ethylene bis oleic acid amide, dioleyl adipic acid amide, N-stearyl stearic acid amide, N-oleyl stearic acid amide, N-stearyl Fatty acid amides such as erucic acid amide, methylol stearic acid amide and methylol behenic acid amide; fatty acid esters such as butyl stearate; alcohols such as ethylene glycol and stearyl alcohol; polyethylene glycol, polypropylene glycol, polytetramethylene glycol and modifications thereof Polyethers composed of substances; Polysiloxanes such as silicone oil and silicone grease; Fluorine compounds such as fluorine oil, fluorine grease, and fluorine-containing resin powder; Paraffin wax, polyethylene wax, amide wax, polypropylene wax, ester Waxes such as wax, carnauba, and microwax; may be at least one selected from the group consisting of.

The compound may contain a flame retardant for environmental safety, recyclability, moldability and low cost of the compound. Flame retardants are selected from the group consisting of, for example, 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. At least one type may be used. The resin composition may contain one flame retardant among the above, and may contain a plurality of flame retardants among the above.

(metal powder)
The metal powder (metal element-containing particles) may contain, for example, at least one selected from the group consisting of simple metals, alloys and metal compounds. The metal element-containing powder may consist of, for example, at least one selected from the group consisting of simple metals, alloys and metal compounds. The alloy may contain at least one selected from the group consisting of solid solutions, eutectics and intermetallic compounds. The alloy may be, for example, stainless steel (Fe--Cr alloy, Fe--Ni--Cr alloy, etc.). The metal compound may be, for example, an oxide such as ferrite. The metal powder may contain one type of metal element or multiple types of metal elements. The metal elements contained in the metal powder may be, for example, base metal elements, noble metal elements, transition metal elements, or rare earth elements. The compound may contain one kind of metallic element-containing powder, or may contain plural kinds of metallic element-containing powders with different compositions.

Metal elements contained in the metal powder include, for example, iron (Fe), copper (Cu), titanium (Ti), manganese (Mn), cobalt (Co), nickel (Ni), zinc (Zn), and 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). The metal powder may further contain elements other than metal elements. Metal powders may include, for example, carbon (C), oxygen (O), beryllium (Be), phosphorus (P), sulfur (S), boron (B), or silicon (Si).

The metal powder may be magnetic powder. The metal powder may be a soft magnetic alloy or a ferromagnetic alloy. Metal powders include, for example, Fe—Si alloy, Fe—Si—Al alloy (sendust), Fe—Ni alloy (permalloy), Fe—Cu—Ni alloy (permalloy), Fe—Co alloy (permalloy). Mendur), Fe-Cr-Si alloy (electromagnetic stainless steel), Nd-Fe-B alloy (rare earth magnet), Sm-Fe-N alloy (rare earth magnet), Al-Ni-Co alloy (alnico magnet), and at least one selected from the group consisting of ferrite. Ferrites may be, for example, spinel ferrites, hexagonal ferrites, or garnet ferrites. The metal powder may be a copper alloy such as a Cu--Sn alloy, a Cu--Sn--P alloy, a Cu--Ni alloy, or a Cu--Be alloy. The metal powder may contain one of the above elements and compositions, or may contain more than one of the above elements and compositions.

The metal powder may be Fe simple substance. The metal powder may be an alloy containing iron (Fe-based alloy). The Fe-based alloy may be, for example, an Fe--Si--Cr-based alloy or an Nd--Fe--B based alloy. The metal element-containing powder may be at least one of amorphous iron powder and carbonyl iron powder. When the metal powder contains at least one of Fe elemental substance and Fe-based alloy, it is easy to produce a compact having a high space factor and excellent magnetic properties from the compound. The metal powder may be Fe amorphous alloy.

Commercially available Fe amorphous alloy powders include, for example, AW2-08, KUAMET-6B2 (manufactured by Epson Atmix Corporation), DAP MS3, DAP MS7, DAP MSA10, DAP PB, DAP PC, and DAP MKV49. , DAP 410L, DAP 430L, DAP HYB series (all trade names manufactured by Daido Steel Co., Ltd.), MH45D, MH28D, MH25D, and MH20D (manufactured by Kobe Steel, Ltd.).

<Compound manufacturing method>
In the production of the compound, the metal powder and the resin composition (components constituting the resin composition) are mixed while being heated. For example, the metal powder and the resin composition may be kneaded with a kneader, a roll, a stirrer, or the like while being heated. By heating and mixing the metal powder and the resin composition, the resin composition adheres to part or all of the surface of the metal element-containing particles constituting the metal powder to coat the metal element-containing particles, and the epoxy in the resin composition Part or all of the resin becomes a semi-cured material. The result is a compound. A compound may be obtained by further adding wax to the powder obtained by heating and mixing the metal powder and the resin composition. The resin composition and wax may be mixed in advance.

For kneading, metal powder, epoxy resin, curing agent, curing accelerator, and coupling agent may be kneaded in a tank. After the metal powder and the coupling agent are put into the tank and mixed, the epoxy resin, the curing agent and the curing accelerator may be put into the tank and the raw materials in the tank are kneaded. After kneading the epoxy resin, the curing agent and the coupling agent in the tank, the curing accelerator may be put in the tank and the raw materials in the tank may be further kneaded. A mixed powder (resin mixed powder) of an epoxy resin, a curing agent, and a curing accelerator is prepared in advance, and then a metal powder and a coupling agent are kneaded to prepare a metal mixed powder. The mixed powder and the resin mixed powder may be kneaded.

The kneading time depends on the type of kneading machine, the volume of the kneading machine, and the production amount of the compound, but for example, it is preferably 1 minute or more, more preferably 2 minutes or more, and 3 minutes or more. is more preferred. The kneading time is preferably 20 minutes or less, more preferably 15 minutes or less, and even more preferably 10 minutes or less. If the kneading time is less than 1 minute, the kneading is insufficient, the moldability of the compound is impaired, and the degree of cure of the compound varies. If the kneading time exceeds 20 minutes, for example, the curing of the resin composition (for example, epoxy resin and phenol resin) proceeds in the tank, and the fluidity and moldability of the compound are likely to be impaired.

When the raw material in the tank is kneaded with a kneader while being heated, the heating temperature is, for example, such that a semi-cured epoxy resin (B-stage epoxy resin) is produced and a cured epoxy resin (C-stage epoxy resin) is produced. Any temperature can be used as long as the temperature suppresses the generation of The heating temperature may be a temperature lower than the activation temperature of the curing accelerator. The heating temperature is, for example, 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 is softened and easily coats the surface of the metal element-containing particles constituting the metal powder, and the semi-cured epoxy resin is easily generated, and during kneading complete hardening of the epoxy resin is likely to be inhibited.

[Molded body]
The molded article according to this embodiment may comprise the compound described above. The molded article according to this embodiment may comprise a cured product of the above compound. The molded article is at least one selected from the group consisting of an uncured resin composition, a semi-cured resin composition (B-stage resin composition), and a cured resin composition (C-stage resin composition). may contain The molded article according to this embodiment may be used as a sealing material for electronic components or electronic circuit boards. According to the present embodiment, it is possible to suppress cracks in the molded body due to the difference in coefficient of thermal expansion between the metal member included in the electronic component or electronic circuit board and the molded body (sealing material).

A cured product of the compound is a cured product of the metal powder and the resin composition. The bending strength at 250° C. of the cured product may be 4.0 MPa or higher, 4.5 MPa or higher, or 4.8 MPa or higher from the viewpoint of increasing the strength of the cured product. The upper limit of bending strength is about 10 MPa. The flexural modulus of the cured product at 250° C. may be 1.3 GPa or less, 1.2 GPa or less, or 1.1 GPa or less from the viewpoint of imparting flexibility to the cured product. The lower limit of the bending elastic modulus is about 0.1 GPa. A value obtained by dividing the bending strength (MPa) at 250°C by the bending elastic modulus (GPa) at 250°C can be used as an index of the reliability of the cured product. The index is preferably 7.3×10 ⁻³ or more, more preferably 7.5×10 ⁻³ or more, and even more preferably 7.8×10 ⁻³ or more. The upper limit of the index is not particularly limited, and may be, for example, 5×10 ⁻² or less.

<Method for manufacturing molded body>
The method for manufacturing a molded article according to this embodiment may include a step of pressing the compound in a mold. The method of manufacturing a molded body may include a step of pressing a compound covering part or all of the surface of the metal member in a mold. The method for producing a molded article may include only the step of pressing the compound in the mold, or may include other steps in addition to this step. The method for manufacturing a molded article may comprise a first step, a second step and a third step. Details of each step are described below.

In the first step, a compound is produced by the method described above.

In the second step, the compound is pressed in a mold to obtain a molded article (B-stage molded article). In the second step, a molded body (B-stage molded body) may be obtained by pressing a compound covering part or all of the surface of the metal member in a mold. In the second step, the resin composition is filled between individual metal element-containing particles that constitute the metal element-containing powder. The resin composition functions as a binding material (binder) and binds the metal element-containing particles to each other.

As a second step, transfer molding of the compound may be performed. In transfer molding, the compound may be pressurized at 5 MPa or more and 50 MPa or less. There is a tendency that the higher the molding pressure, the easier it is to obtain a molded article having excellent mechanical strength. Considering the mass productivity of the molded product and the life of the mold, the molding pressure is preferably 8 MPa or more and 20 MPa or less. The density of the compact formed by transfer molding may be 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, a molded body having excellent mechanical strength can be easily obtained. Transfer molding WHEREIN: You may implement a 2nd process and a 3rd process collectively.

In the third step, the compact is cured by heat treatment to obtain a C-stage compact. The heat treatment temperature may be any temperature at which the resin composition in the molded article is sufficiently cured. The temperature of the heat treatment may be 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 oxidation of the metal powder in the compact, it is preferable to perform the heat treatment in an inert atmosphere. If the heat treatment temperature exceeds 300° C., the trace amount of oxygen inevitably contained in the heat treatment atmosphere may oxidize the metal powder or deteriorate the cured resin. In order to sufficiently cure the resin composition while suppressing oxidation of the metal powder and deterioration of the cured resin product, the holding time of the heat treatment temperature is preferably several minutes to 10 hours, more preferably 3 minutes or more. It can be less than an hour.

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

The details of each component used in the preparation of the compounds of Examples and Reference Examples are shown below.

(Epoxy resin)
Biphenylene aralkyl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., trade name: NC-3000, epoxy equivalent: 275 g / eq)
Polyfunctional epoxy resin (trade name: TECHMORE VG-3101L manufactured by Printec Co., Ltd., epoxy equivalent: 215 g / eq)
(curing agent)
Phenolic novolac resin (trade name: HF-3M manufactured by Meiwa Kasei Co., Ltd.)

(coupling agent)
Polyfunctional silane compound having a mercapto group (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: X-12-1154, kinematic viscosity (25° C.): 1460 mm ² /s)
Polyfunctional silane compound having an epoxy group (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KR-517, kinematic viscosity (25° C.): 14.7 mm ² /s)
Polyfunctional silane compound having an acryloyl group (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KR-513, kinematic viscosity (25° C.): 40 mm ² /s)
3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM-403, kinematic viscosity (25° C.): 3.05 mm ² /s)
3-mercaptopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM-803, kinematic viscosity (25° C.): 1.36 mm ² /s)

(Curing accelerator)
Aromatic dimethyl urea (product name: U-CAT3512T manufactured by San-Apro Co., Ltd.)
(Release agent)
Partially saponified montan acid ester wax (manufactured by Clariant Chemicals Co., Ltd., trade name: LICOWAX-OP)

(metal powder)
Amorphous iron powder (manufactured by Epson Atmix Corporation, trade name: 9A4-II, average particle size 24 μm)
FeSiCr alloy powder (manufactured by Sintokogyo Co., Ltd., average particle size: 2.1 μm)

[Preparation of compound]
(Examples 1 to 5)
The epoxy resin, curing agent, curing accelerator, and release agent shown in Table 1 were charged into a plastic container in the amounts shown in the table (unit: g). A resin mixture was prepared by mixing these materials in a plastic container for 10 minutes. The resin mixture corresponds to all components other than the coupling agent in the resin composition.

Amorphous iron powder and FeSiCr alloy powder (mass ratio 82:18) were uniformly mixed for 5 minutes with a pressurized twin-screw kneader (manufactured by Nihon Spindle Mfg. Co., Ltd., capacity 5 L) to prepare metal powder. A coupling agent shown in Table 1 was added to the metal powder in the twin-screw kneader. Subsequently, the contents of the twin-screw kneader were heated to 90° C., and the contents of the twin-screw kneader were mixed for 10 minutes while maintaining the temperature. Subsequently, the above resin mixture was added to the contents of the twin-screw kneader, and the contents were melted and kneaded for 15 minutes while maintaining the temperature of the contents at 120°C. After cooling the kneaded material obtained by the above melting and kneading to room temperature, the kneaded material was pulverized with a hammer until the kneaded material had a predetermined particle size. In addition, the above-mentioned "melting" means melting of at least a part of the resin composition in the contents of the twin-screw kneader. The metal powder in the compound does not melt during the compound preparation process. Compounds of Examples 1 to 5 were prepared by the above method.

(Comparative Examples 1 to 3)
Compounds of Comparative Examples 1 to 3 were prepared in the same manner as in Examples except that the types and blending amounts of each component were changed as shown in Table 2.

[Compound evaluation]
The compounds obtained in Examples and Reference Examples were evaluated as follows. Results are shown in Tables 1 and 2.

(bending test)
The compound was transfer molded under conditions of a mold temperature of 175° C., a molding pressure of 13.5 MPa, and a curing time of 360 seconds, and then post-cured at 180° C. for 6 hours to obtain a test piece. The dimensions of the test piece were 80 mm in length×10 mm in width×3.0 mm in thickness.

A three-point support type bending test was performed on the test piece at 250° C. using an autograph with a constant temperature bath. As the autograph, AGS-500A manufactured by Shimadzu Corporation was used. In the bending test, one side of the specimen was supported by two fulcrums. A load was applied to the other side of the specimen at a central location between the two fulcrums. The load was measured when the specimen broke. The measurement conditions of the bending test were as follows.
Distance Lv between two fulcrums: 64.0±0.5mm
Head speed: 2.0±0.2mm/min Chart speed: 100mm/min Chart full scale: 490N (50kgf)

Bending strength σ (unit: MPa) was calculated based on the following formula (A). A flexural modulus E (unit: GPa) was calculated based on the following formula (B). In the following formula, "P" is the load (unit: N) when the test piece is destroyed. “Lv” is the distance (unit: mm) between two fulcrums. "W" is the width of the test piece (unit: mm). "t" is the thickness of the test piece (unit: mm). "F/Y" is the slope of the linear portion of the load-deflection curve (unit: N/mm).
σ=(3×P×Lv)/(2×W×t ² ) (A)
E=[Lv ³ /(4×W×t ³ )]×(F/Y) (B)

(reliability)
A value obtained by dividing the flexural strength (MGa) at 250°C by the flexural modulus (GPa) at 250°C was used as an index for evaluating reliability. A higher value means a better balance between strength and elastic modulus.

(voltage resistance)
The compound was transfer molded under the conditions of a mold temperature of 175°C, a molding pressure of 13.5 MPa, and a curing time of 360 seconds, and then post-cured at 180°C for 6 hours to prepare a test piece with a thickness of 2.0 mm. . In the withstand voltage test, a stainless steel plate connected to a ground wire, a conductive rubber plate, a test piece, and a stainless steel electrode with a diameter of 10 mm connected to a high voltage wire were placed in this order on an insulating plate. The high voltage line and the ground line were connected to the high voltage output terminal and the ground terminal of the high voltage amplifier, respectively. The waveform output of the function generator was input to a high-voltage amplifier to generate a test voltage from 0 V to a maximum of 2000 V at a rate of 10 V per second, and applied to the test piece. The voltage was read when the current through the specimen exceeded 10 mA. Stainless steel electrodes were then placed at different positions on the specimen and voltages were applied in the same manner. The test was repeated 14 times, and the median value of the read voltage was taken as the withstand voltage (dielectric breakdown voltage: V/mm) of the test piece.

ADVANTAGE OF THE INVENTION The compound which concerns on this invention is excellent in the balance of the strength and elastic modulus at high temperature, and can form the molded object which is excellent in withstand voltage property.

Claims (6)

A resin composition containing metal powder, an epoxy resin, a curing agent, and a coupling agent,
A compound, wherein the coupling agent comprises a polyfunctional silane compound having a kinematic viscosity of 10 to 2000 mm ² /s at 25°C. 2. The polyfunctional silane compound according to claim 1, which has at least two functional groups selected from the group consisting of (meth)acryloyl groups, vinyl groups, epoxy groups, amino groups, isocyanate groups, and mercapto groups. compound. The compound according to claim 1 or 2, wherein the content of said polyfunctional silane compound is 1.0 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of said epoxy resin. The compound according to any one of claims 1 to 3, wherein the content of the metal powder is 90% by mass or more and less than 100% by mass. A molded article comprising the compound according to any one of claims 1 to 4. A cured product of the compound according to any one of claims 1 to 4.