Coil sealing resin composition, electronic component device, and method for producing electronic component device

Abstract

This coil sealing resin composition contains: a magnetic powder; an epoxy resin; a curing agent; and a curing accelerator containing an intramolecular salt of a phosphine having an aryl group.

Description

[Technical field]

[0001] The present invention relates to a resin composition for sealing a coil, an electronic component device, and a method for producing an electronic component device. [Background technology]

[0002] Compounds containing metal powder and a resin composition are used as raw materials for various industrial products such as inductors, electromagnetic shields, and bonded magnets depending on the physical properties of the metal powder (see, for example, Patent Document 1). Also, a molded coil has been disclosed in which a coil is sealed with a magnetic molding resin in which magnetic powder is dispersed in resin, and the magnetic molding resin contains 65 to 80 vol% of magnetic powder, which is mainly made of metal-based magnetic powder (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-13803 A [Patent Document 2] JP 2009-260116 A Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Documents 1 and 2 disclose a molded coil in which the coil is sealed with a resin composition containing a magnetic powder and a resin. It is desirable that the resin composition used for sealing such a coil has a low rate of change in melt viscosity over time and excellent storage stability in order to suppress non-filling of the resin composition due to an increase in melt viscosity when sealing the coil using a mold, for example.

[0005] An object of one aspect of the present disclosure is to provide a resin composition for sealing a coil that has a low rate of change in melt viscosity over time and has excellent storage stability, as well as an electronic component device and a method for manufacturing an electronic component device using the same. [Means for solving the problem]

[0006] Specific means for achieving the above object are as follows. <1> A resin composition for sealing a coil, comprising: a magnetic powder; an epoxy resin; a curing agent; and a curing accelerator including an inner salt of a phosphine having an aryl group. <2> Further includes a release agent <1> The coil sealing resin composition according to claim 1 . <3> The content of the magnetic powder is 60 mass % or more based on the total amount of the resin composition for sealing a coil. <1> or <2> The coil sealing resin composition according to claim 1 . <4> The inner salt includes an inner salt of triphenylphosphine. <1> ~ <3> 13. The coil sealing resin composition according to claim 12, <5> A coil and a coil sealing device <1> ~ <4> and a cured product of the coil sealing resin composition according to any one of the above items. <6> Coil <1> ~ <4> 13. A method for producing an electronic component device, comprising the step of encapsulating the device with the coil encapsulating resin composition according to any one of claims 1 to 22. Effect of the Invention

[0007] According to one aspect of the present disclosure, it is possible to provide a resin composition for sealing a coil that has a low rate of change in melt viscosity over time and has excellent storage stability, as well as an electronic component device and a method for producing an electronic component device using the same. [Brief description of the drawings]

[0008] [Figure 1] 1 is a graph showing the relationship between the retention time of the coil sealing resin compositions of Examples 1 and 2 and Comparative Examples 1 and 2 under conditions of 25° C. and a relative humidity of 50% and the minimum melt viscosity retention rate. [Diagram 2]1 is a graph showing the relationship between the gel time retention and the leaving time under conditions of 25° C. and a relative humidity of 50% and 30° C. and a relative humidity of 70% for the coil sealing resin composition of Example 1. [Diagram 3] 1 is a graph showing the relationship between the gel time retention and the leaving time under conditions of 25° C. and a relative humidity of 50% and 30° C. and a relative humidity of 70% for the coil sealing resin composition of Example 2. [Figure 4] 1 is a graph showing the relationship between the gel time retention and the leaving time under conditions of 25° C. and a relative humidity of 50% and 30° C. and a relative humidity of 70% for the coil sealing resin composition of Comparative Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiment for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiment. In the following embodiment, the components (including element steps, etc.) are not essential unless specifically stated. The same applies to the numerical values ​​and their ranges, and they do not limit the present invention.

[0010] In the present disclosure, a numerical range indicated using "~" includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in the present disclosure in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples. In the present disclosure, each component may contain multiple types of corresponding substances. When multiple types of substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified. In the present disclosure, the particles corresponding to each component may include multiple types of particles. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified.

[0011] <Coil encapsulation resin composition> The coil sealing resin composition of the present disclosure includes a magnetic powder, an epoxy resin, a curing agent, and a curing accelerator including an inner salt of a phosphine having an aryl group. The coil sealing resin composition may further include other components as necessary. The coil sealing resin composition may be a resin composition used to seal a coil to manufacture an electronic component device.

[0012] The coil sealing resin composition of the present disclosure contains an epoxy resin, a curing agent, and a curing accelerator containing an inner salt of a phosphine having an aryl group, and thus has a low melt viscosity change rate over time and excellent storage stability. For example, the coil sealing resin composition of the present disclosure contains a curing accelerator containing an inner salt of a phosphine having an aryl group, and thus has a low melt viscosity change rate over time and excellent storage stability compared to a coil sealing resin composition containing a curing accelerator containing an imidazole compound without containing an inner salt of a phosphine having an aryl group. Although the detailed reason for this is not necessarily clear, it is considered that the use of a curing accelerator containing an inner salt of a phosphine having an aryl group increases the reactivity of the epoxy resin not in a wide temperature range including room temperature but in a specific temperature range, and therefore the melt viscosity change rate over time is low and the storage stability is excellent.

[0013] (magnetic powder) The resin composition for coil sealing according to the present disclosure contains a magnetic powder. The magnetic powder preferably contains at least one selected from the group consisting of a simple metal, an alloy, and a metal compound. The specific gravity (density) of the magnetic powder is, for example, 5 g / cm. 3or more. The magnetic powder may be, for example, at least one selected from the group consisting of a simple metal, an alloy, and a metal compound. The alloy may contain at least one selected from the group consisting of a solid solution, a eutectic, and an intermetallic compound. 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 magnetic powder may contain one type of metal element or multiple types of metal elements. Examples of the metal elements contained in the magnetic powder include base metal elements, precious metal elements, transition metal elements, and rare earth elements. The coil sealing resin composition may contain one type of magnetic powder, or may contain multiple types of magnetic powder.

[0014] The metal elements contained in the magnetic powder include 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). The magnetic powder may contain elements other than metal elements. The magnetic powder may contain at least one selected from the group consisting of carbon (C), oxygen (O), beryllium (Be), phosphorus (P), sulfur (S), boron (B) and silicon (Si).

[0015] The magnetic powder may be a soft magnetic alloy or a ferromagnetic alloy. The magnetic powder may be, for example, a magnetic powder containing at least one selected from the group consisting of Fe-Si alloys, Fe-Si-Al alloys (e.g., Sendust), Fe-Ni alloys (e.g., Permalloy), Fe-Cu-Ni alloys (e.g., Permalloy), Fe-Co alloys (e.g., Permendur), Fe-Cr-Si alloys (e.g., electromagnetic stainless steel), Nd-Fe-B alloys (e.g., rare earth magnets), Sm-Fe-N alloys (e.g., rare earth magnets), Al-Ni-Co alloys (e.g., Alnico magnets) and ferrites. Examples of ferrites include spinel ferrites, hexagonal ferrites, and garnet ferrites.

[0016] The magnetic powder may be Fe alone. The magnetic 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 magnetic powder may be at least one of an amorphous iron powder and a carbonyl iron powder. When the magnetic powder contains at least one of Fe alone and an Fe-based alloy, a cured product having a high space factor and excellent magnetic properties can be easily produced from the resin composition for sealing a coil. The magnetic powder may be an Fe amorphous alloy.

[0017] From the viewpoints of the magnetic properties when made into an electronic component device and the fluidity of the resin composition for coil sealing, the content of the magnetic powder is preferably 60 mass% or more, more preferably 80 mass% to 99 mass%, even more preferably 90 mass% to 98 mass%, and particularly preferably 94.5 mass% to 97 mass%, relative to the total amount of the resin composition for coil sealing.

[0018] The volume average particle size of the magnetic powder is not particularly limited, and may be, for example, 1 μm to 300 μm, 3 μm to 100 μm, or 4 μm to 50 μm. In the present disclosure, the volume average particle size is determined as the particle size (50% D) where the cumulative volume from the small particle size side is 50% in the particle size distribution curve of the cumulative volume by the laser diffraction scattering type particle size distribution measurement method. For example, it can be measured using a particle size distribution measurement device using the laser light scattering method (for example, "SALD-3000" by Shimadzu Corporation).

[0019] The shape of each particle constituting the magnetic powder is not limited and may be, for example, spherical, flat, prismatic or acicular. The resin composition for sealing a coil may contain multiple types of magnetic powder having different volume average particle sizes.

[0020] (Epoxy resin) The resin composition for sealing a coil according to the present disclosure contains an epoxy resin. The epoxy resin may be, for example, a resin having two or more epoxy groups in one molecule.

[0021] Examples of the epoxy resin include biphenyl type epoxy resins, stilbene type epoxy resins, diphenylmethane type epoxy resins, sulfur atom-containing epoxy resins, novolac type epoxy resins, dicyclopentadiene type epoxy resins, salicylaldehyde type epoxy resins, naphthol and phenol copolymer type epoxy resins, epoxidized products of aralkyl type phenol resins, bisphenol type epoxy resins, epoxy resins containing a bisphenol skeleton, glycidyl ether type epoxy resins of alcohols, glycidyl ether type epoxy resins of paraxylylene and / or metaxylylene modified phenol resins, glycidyl ether type epoxy resins of terpene modified phenol resins, and the like. The epoxy resin may be at least one selected from the group consisting of ether type epoxy resins, cyclopentadiene type epoxy resins, glycidyl ether type epoxy resins of polycyclic aromatic ring-modified phenolic resins, glycidyl ether type epoxy resins of naphthalene ring-containing phenolic resins, glycidyl ester type epoxy resins, glycidyl type or methylglycidyl type epoxy resins, alicyclic type epoxy resins, halogenated phenol novolac type epoxy resins, orthocresol novolac type epoxy resins, hydroquinone type epoxy resins, trimethylolpropane type epoxy resins, and linear aliphatic epoxy resins obtained by oxidizing an olefin bond with a peracid such as peracetic acid.

[0022] From the viewpoint of fluidity, the epoxy resin may be at least one selected from the group consisting of biphenyl type epoxy resins, orthocresol 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 novolac type epoxy resins, or may be at least one selected from the group consisting of biphenyl type epoxy resins and bisphenol type epoxy resins, or may be at least one selected from the group consisting of biphenylene aralkyl type epoxy resins and bisphenol A type epoxy resins.

[0023] 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 is excellent in fluidity. The crystalline epoxy resin (highly crystalline epoxy resin) may be, for example, at least one selected from the group consisting of hydroquinone type epoxy resin, bisphenol type epoxy resin, thioether type epoxy resin, and biphenyl type epoxy resin.

[0024] The epoxy equivalent of the epoxy resin is not particularly limited. From the viewpoint of the balance of various properties such as moldability, heat resistance, and electrical reliability, the epoxy equivalent of the epoxy resin is preferably 60 g / eq to 1000 g / eq, more preferably 80 g / eq to 500 g / eq, and further preferably 100 g / eq to 300 g / eq. The epoxy equivalent of the epoxy resin is measured by dissolving a weighed amount of the epoxy resin in a solvent such as methyl ethyl ketone, adding acetic acid and a tetraethylammonium bromide acetate solution, and then subjecting the solution to potentiometric titration with a perchloric acid acetate standard solution. An indicator may be used in this titration.

[0025] From the viewpoints of strength, fluidity, heat resistance, moldability, etc., the content of the epoxy resin in the resin composition for sealing a coil is preferably 0.5% by mass to 20% by mass, more preferably 1% by mass to 10% by mass, and even more preferably 1.5% by mass to 5% by mass.

[0026] (hardening agent) The coil sealing resin composition of the present disclosure contains a curing agent. The type of curing agent is not particularly limited, and can be selected from those generally used as components of epoxy resin compositions. The curing agent may be used alone or in combination of two or more types. Curing agents are classified into curing agents that cure epoxy resins in the range of low to room temperature, and heat-curing type curing agents that cure epoxy resins by heating. Examples of curing agents that cure epoxy resins in the range of low to room temperature include aliphatic polyamines, polyaminoamides, and polymercaptans. Examples of heat-curing type curing agents include aromatic polyamines, acid anhydrides, phenolic resins, and dicyandiamide (DICY).

[0027] When a curing agent that cures an epoxy resin at a temperature ranging from low temperature to room temperature is used, the glass transition point of the cured product obtained by curing the coil sealing resin composition is low, and the cured product tends to be soft. In addition, a molded article formed from the coil sealing resin composition also tends to be soft.

[0028] On the other hand, from the viewpoint of improving the heat resistance and mechanical strength of the molded body, the curing agent is preferably a heat-curing type curing agent, and a phenol resin is more preferable.

[0029] The phenolic resin may be at least one selected from the group consisting of, for example, aralkyl type phenolic resin, dicyclopentadiene type phenolic resin, salicylaldehyde type phenolic resin, novolac type phenolic resin, copolymer type phenolic resin of benzaldehyde type phenol and aralkyl type phenol, paraxylylene and / or metaxylylene modified phenolic resin, melamine modified phenolic resin, terpene modified phenolic resin, dicyclopentadiene type naphthol resin, cyclopentadiene modified phenolic resin, polycyclic aromatic ring modified phenolic resin, biphenyl type phenolic resin, and triphenylmethane type phenolic resin. The phenolic resin may also contain biphenyl type phenolic resin and triphenylmethane type phenolic resin. The phenolic resin may be a copolymer composed of two or more of the above.

[0030] 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 resorcin, catechol, bisphenol A, bisphenol F, and substituted or unsubstituted biphenol.

[0031] The hydroxyl equivalent of the phenol resin is not particularly limited, but from the viewpoint of the balance of various properties such as moldability, heat resistance, and electrical reliability, it is preferably 10 g / eq to 1000 g / eq, and more preferably 30 g / eq to 500 g / eq. The hydroxyl equivalent of the phenolic resin is a value calculated based on the hydroxyl value measured in accordance with JIS K0070:1992.

[0032] The equivalent ratio of the epoxy resin to the curing agent (moles of epoxy groups in the epoxy resin / moles of active hydrogen in the curing agent) is not particularly limited, and is preferably 0.5 to 1.5, more preferably 0.6 to 1.4, and even more preferably 0.8 to 1.2, from the viewpoint of keeping the unreacted amounts of each to a minimum. When the equivalent ratio is 0.5 or more, the elastic modulus of the cured product obtained by curing the coil sealing resin composition tends to be excellent. On the other hand, when the equivalent ratio is 1.5 or less, the mechanical strength of the cured product tends to decrease.

[0033] (Cure accelerator) The coil sealing resin composition includes a curing accelerator containing an inner salt of a phosphine having an aryl group. The inner salt of a phosphine having an aryl group is preferably an inner salt of a phosphine having at least one aryl group bonded to a phosphorus element, and more preferably an inner salt of a cation containing a phosphine skeleton having at least one aryl group bonded to a phosphorus element and an anion.

[0034] Examples of the aryl group in the phosphine having an aryl group include unsubstituted aryl groups and substituted aryl groups such as a phenyl group, a p-tolyl group, a m-tolyl group, an o-tolyl group, a p-methoxyphenyl group, a m-methoxyphenyl group, an o-methoxyphenyl group, a p-hydroxyphenyl group, a m-hydroxyphenyl group, an o-hydroxyphenyl group, a 2,5-dihydroxyphenyl group, a 4-(4-hydroxyphenyl)phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-(2-hydroxynaphthyl) group, and a 1-(4-hydroxynaphthyl) group.

[0035] The phosphine having an aryl group may have an alkyl group bonded to the phosphorus atom, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an s-butyl group, a t-butyl group, an octyl group, a cyclohexyl group, or other linear, branched, or cyclic alkyl group.

[0036] Examples of phosphines having an aryl group include methyldiphenylphosphine, triphenylphosphine, tris(4-methylphenyl)phosphine, diphenylphosphine, and phenylphosphine, and among these, triphenylphosphine is preferred.

[0037] The inner salt of a phosphine having an aryl group preferably includes an inner salt of triphenylphosphine. The inner salt of triphenylphosphine is preferably an inner salt of a cation and an anion having a triphenylphosphine skeleton.

[0038] Examples of the cation containing a triphenylphosphine skeleton include a triphenylphosphine cation, a reaction product of triphenylphosphine and a compound having an aryl group, etc. As the cation containing a triphenylphosphine skeleton, a reaction product of triphenylphosphine and a compound having an aryl group is preferable from the viewpoint of the rate of change in melt viscosity over time.

[0039] The reaction product of triphenylphosphine with a compound having an aryl group is preferably a reaction product of triphenylphosphine with a compound having two hydroxyl groups and an aryl group, and more preferably a reaction product of triphenylphosphine with hydroquinone.

[0040] Examples of the anion include anions of aryl compounds having two or more carboxyl groups, anions of aryl compounds having two or more hydroxyl groups, etc. More specifically, examples of the anion include anions of phthalic acid, benzene-1,2,4,5-tetracarboxylic acid, p-benzoquinone, etc.

[0041] The content of the inner salt of a phosphine having an aryl group in the curing accelerator is not particularly limited as long as it is within a range in which the effects of the present invention can be achieved, and may be, for example, 50 mass% or more, 70 mass% or more, 90 mass% or more, or 100 mass% relative to the total amount of the curing accelerator.

[0042] The content of the curing accelerator in the coil sealing resin composition is not particularly limited as long as it is an amount that can obtain a curing acceleration effect. The content of the curing accelerator is preferably 0.1 parts by mass to 10 parts by mass, more preferably 1 part by mass to 5 parts by mass, relative to 100 parts by mass of the epoxy resin, from the viewpoints of the curing acceleration effect and storage stability. In addition, the content of the curing accelerator is preferably 0.05 parts by mass to 5 parts by mass, more preferably 0.5 parts by mass to 2.5 parts by mass, relative to 100 parts by mass of the epoxy resin and the curing agent (e.g., phenolic resin) in total, from the viewpoints of the curing acceleration effect and storage stability.

[0043] The curing accelerator may contain a curing accelerator other than the inner salt of the phosphine having an aryl group (hereinafter, "other curing accelerator"). The other curing accelerator may be a cycloamidine compound such as 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 1,5-diazabicyclo[4.3.0]-5-nonene, or 5,6-dibutylamino-1,8-diazabicyclo[5.4.0]-7-undecene; a cycloamidine compound containing maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, or phenyl-1,4-benzoquinone, or a quinone compound, such as diazophenylmethane, or a phenolic resin. Compounds having intramolecular polarization obtained by adding a compound having a π bond such as; tertiary amine compounds such as benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; derivatives of tertiary amine compounds; imidazole compounds such as 2-methylimidazole, 2-phenylimidazole, and 2-phenyl-4-methylimidazole; derivatives of imidazole compounds; organic phosphine compounds such as tributylphosphine; phosphorus compounds having intramolecular polarization obtained by adding a compound having a π bond such as maleic anhydride, the above-mentioned quinone compounds, diazophenylmethane, and phenol resin to an organic phosphine compound. Other curing accelerators may be used alone or in combination of two or more.

[0044] (Release agent) The coil sealing resin composition of the present disclosure preferably further contains a mold release agent. When the coil sealing resin composition contains a mold release agent, the cured product can be easily separated from a mold during the process of producing a cured product from the resin composition using a mold or the like.

[0045] Examples of the release agent include polyolefins, fatty acids such as higher fatty acids, fatty acid esters, partially saponified fatty acid esters, fatty acid salts, fatty acid amides, alcohols, polyethers, polysiloxanes, fluorine compounds, metal soaps, and natural waxes. From the viewpoint of easily improving the fluidity of the coil sealing resin composition, it is preferable that the release agent contains a fatty acid.

[0046] The polyolefin may be, for example, at least one of polyethylene and polypropylene. The polyolefin may be, for example, at least one polar wax selected from the group consisting of polyethylene oxide, grafted polyolefin, and copolymers. The polyolefin may be, for example, at least one of polyethylene and polyethylene oxide.

[0047] Examples of the release agent include fatty acids such as montanic acid, stearic acid, 12-oxystearic acid, and lauric acid, and 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-ethylhexoate; 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 adipate amide, ethylene bisoleic acid amide, dioleyl adipate amide, The fatty acid amide may be at least one selected from the group consisting of fatty acid amides such as N-stearyl stearamide, N-oleyl stearamide, N-stearyl erucamide, methylol stearamide, and methylol behenamide; fatty acid esters such as butyl stearate; alcohols such as ethylene glycol and stearyl alcohol; polyethers such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and modified products thereof; polysiloxanes such as silicone oil and silicone grease; fluorine compounds such as fluorine-based oil, fluorine-based grease, and fluorine-containing resin powder; and waxes such as paraffin wax, amide wax, ester wax, carnauba wax, and microwax. The release agent contained in the coil sealing resin composition may be appropriately selected depending on the requirements for designing the composition, such as the flowability and releasability of the coil sealing resin composition, the temperature and pressure during molding, and the melting point and melt viscosity of the release agent.

[0048] When the coil sealing resin composition contains a release agent, the content of the release agent is, from the viewpoints of releasability and mechanical strength of the cured product, preferably 0.01 mass % to 0.5 mass %, more preferably 0.05 mass % to 0.3 mass %, and even more preferably 0.1 mass % to 0.2 mass %, relative to the total amount of the coil sealing resin composition.

[0049] When the resin composition for coil sealing contains a release agent, the content of the release agent is preferably 0.5% by mass to 20% by mass, more preferably 1% by mass to 10% by mass, and further preferably 3% by mass to 7% by mass, based on the total amount of the epoxy resin, from the viewpoints of releasability and mechanical strength of the cured product.

[0050] [Various additives] In addition to the above-mentioned components, the coil sealing resin composition may contain various additives such as resins other than the epoxy resins and curing agents exemplified below (hereinafter also referred to as "other resins"), coupling agents, ion exchangers, release agents, flame retardants, colorants, stress relaxation agents, etc. The coil sealing resin composition may contain various additives known in the art as necessary in addition to the additives exemplified below.

[0051] (Other resins) The coil sealing resin composition may contain other resins other than the epoxy resin and the curing agent. Examples of the other resins include silicone resins, polyamide resins, polyamideimide resins, thermoplastic resins, and the like. The thermoplastic resin may be, for example, 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 a thermosetting resin and a thermoplastic resin. The resin composition may contain a silicone resin.

[0052] (Coupling Agent) When the resin composition for coil sealing contains an inorganic filler, it may contain a coupling agent to enhance adhesion between the resin component and the magnetic powder. Examples of the coupling agent include known coupling agents such as silane-based compounds such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, and vinylsilane, titanium-based compounds, aluminum chelate compounds, and aluminum / zirconium-based compounds.

[0053] (Method for preparing resin composition for coil encapsulation) The method for preparing the coil sealing resin composition is not particularly limited. When the coil sealing resin composition is solid, a general method includes a method in which a predetermined amount of components are thoroughly mixed with a mixer or the like, then melt-kneaded with a mixing roll, an extruder, or the like, cooled, and pulverized. More specifically, for example, a method in which a predetermined amount of the above-mentioned components are uniformly stirred and mixed, kneaded with a kneader, roll, extruder, or the like that has been heated to 70°C to 140°C in advance, cooled, and pulverized can be mentioned. When the resin composition for sealing a coil is in a liquid state, a typical method includes weighing out predetermined amounts of components and dispersing and kneading them using a three-roll mill, a crusher, a planetary mixer, a hard mixer, a homomixer, etc. In addition, a method using a master batch in which each component is pre-dispersed and pre-heated is preferred from the viewpoints of uniform dispersion and fluidity.

[0054] When the coil sealing resin composition is solid, the shape is not particularly limited, and examples of the shape include powder, granules, tablets, etc. When the coil sealing resin composition is in tablet form, it is preferable that the dimensions and mass of the tablet are set to be suitable for the molding conditions of the package, from the viewpoint of handleability.

[0055] <Electronic component equipment> The electronic component device of the present disclosure includes a coil and a cured product of the coil encapsulating resin composition of the present disclosure that encapsulates the coil. The electronic component device of the present disclosure can be obtained, for example, by curing the coil encapsulating resin composition that covers at least a part of the coil. The cured product can be obtained, for example, by heating the coil sealing resin composition at 100° C. to 250° C. for 1 to 10 hours, preferably at 130° C. to 230° C. for 1 to 8 hours.

[0056] The electronic component device of the present disclosure can be obtained, for example, by filling a mold having a coil arranged therein with the resin composition for coil encapsulation of the present disclosure and curing the resin composition for coil encapsulation filled in the mold. Since the resin composition for coil encapsulation of the present disclosure has a low rate of change in melt viscosity over time and excellent storage stability, it tends to be excellent in fillability into a mold and excellent in productivity for electronic component devices.

[0057] The electronic component device of the present disclosure may be a molded coil in which a coil is sealed with a resin composition for coil sealing, and examples of such a molded coil include an element portion obtained by mounting active elements such as semiconductor chips, transistors, diodes, and thyristors, and passive elements such as capacitors and resistors, together with a coil, on a supporting member such as a lead frame, a pre-wired tape carrier, a wiring board, glass, a silicon wafer, or an organic substrate, and sealing the resulting element portion with the resin composition for coil sealing.

[0058] <Electronic component device manufacturing method> The method for producing an electronic component according to the present disclosure includes a step of encapsulating a coil with the coil encapsulation resin composition according to the present disclosure. The coil encapsulation resin composition according to the present disclosure is suitable as a coil encapsulant. Examples of methods for sealing a coil with a solid coil sealing resin composition include low pressure transfer molding, injection molding, and compression molding. EXAMPLES

[0059] The present invention will now be described in more detail with reference to examples, but the scope of the present invention is not limited to these examples. Unless otherwise specified, "parts" and "%" are based on mass.

[0060] Details of the epoxy resin, curing agent, curing accelerator, silane compound, release agent and magnetic powder used in the examples and comparative examples are as follows. (Epoxy resin) Epoxy resin A: Biphenylene aralkyl type epoxy resin (epoxy equivalent: 277 g / eq) Epoxy resin B: Trifunctional bisphenol A type epoxy resin (epoxy equivalent: 205g / eq - 215g / eq) (hardening agent) Hardener A: Biphenyl-type phenolic resin (hydroxyl equivalent: 202 g / eq) Hardener B: Triphenylmethane type phenolic resin (hydroxyl equivalent: 103 g / eq) (Cure accelerator) Curing accelerator A: Inner salt of the reaction product of triphenylphosphine and hydroquinone with phthalate anion Curing accelerator B: Inner salt of triphenylphosphine and p-benzoquinone Curing accelerator C···2-heptadecylimidazole Curing accelerator D: 2-phenyl-4-methylimidazole Curing accelerator E···2-phenyl-4-methyl-5-hydroxymethylimidazole (Silane compounds) Silane compound A: 3-glycidyloxypropyltrimethoxysilane Silane compound B: 3-mercaptopropyltrimethoxysilane (Release agent) Release agent A: Zinc laurate Release agent B: Partially saponified montanic acid ester (magnetic powder) Magnetic powder 1: Amorphous iron powder (volume average particle size: 24 μm) Magnetic powder 2: Amorphous iron powder (volume average particle size: 5.3 μm)

[0061] [Example 1] (Preparation of Resin Mixture) 50 parts of epoxy resin A, 50 parts of epoxy resin B, 41.6 parts of hardener A, 21.8 parts of hardener B, 2 parts of hardener accelerator A, 4 parts of release agent A, and 2 parts of release agent B were charged into a plastic container. These raw materials were mixed in the plastic container for 10 minutes to prepare a resin mixture. In this example, the resin mixture corresponds to all components of the resin composition for sealing a coil, except for the magnetic powder and the coupling agent.

[0062] (Preparation of coil sealing resin composition) A total of 4737 parts of magnetic powder 1 and magnetic powder 2 (mixing ratio: 82:18 by mass) was mixed for 5 minutes in a pressure-type twin-screw kneader (manufactured by Nihon Spindle Manufacturing Co., Ltd., capacity: 5 L) to prepare a magnetic powder. A mixture of 4.5 parts of silane compound A and 1 part of silane compound B (mixing ratio as shown in Table 1) was added to the magnetic powder in the twin-screw kneader. Then, the contents of the twin-screw kneader were heated to 70°C, and the contents of the twin-screw kneader were mixed for 10 minutes while maintaining the temperature. Then, 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 90°C. The kneaded product obtained by the above melting and kneading was cooled to room temperature, and then crushed with a hammer until the kneaded product had a predetermined particle size, to prepare a resin composition for sealing a coil. The above "melting" means melting at least a part of the resin composition in the contents of the twin-screw kneader. The magnetic powder in the resin composition for sealing a coil does not melt during the preparation process of the resin composition for sealing a coil.

[0063] [Example 2] A coil sealing resin composition was prepared in the same manner as in Example 1, except that in Example 1, 2.4 parts of curing accelerator B was used instead of 2 parts of curing accelerator A, and the total amount of magnetic powder 1 and magnetic powder 2 was changed so that the mass ratio of the magnetic powder in the coil sealing resin composition was 96.4%.

[0064] [Comparative Example 1] A coil sealing resin composition was prepared in the same manner as in Example 1, except that curing accelerators C and D were used in place of curing accelerator A in the amounts shown in Table 1.

[0065] [Comparative Example 2] A coil sealing resin composition was prepared in the same manner as in Example 1, except that the curing accelerator E was used instead of the curing accelerator A in Example 1.

[0066] In Table 1, "magnetic powder / %" means the combined content of magnetic powders 1 and 2 relative to the total amount of the coil sealing resin composition. The numerical values ​​of the epoxy resin, curing agent, curing accelerator, silane compound, and release agent in Table 1 mean the parts by mass of each used in preparing the coil sealing resin composition, and further mean the mass ratio of each in the coil sealing resin composition excluding the magnetic powder. In addition, in Table 1, blank spaces indicate "not blended."

[0067] [Table 1]

[0068] (Measurement of minimum melt viscosity) The minimum melt viscosity at 130°C was measured using the coil sealing resin composition of each of the Examples and Comparative Examples. The results are shown in Table 2 below. The minimum melt viscosity was measured using a flow tester CFT-100 (manufactured by Shimadzu Corporation) under the measurement conditions of 130°C, preheating for 20 seconds, and a load of 100 kg. The distance (unit: mm) that the plunger was pushed in until the flow of the coil sealing resin composition stopped was measured as the stroke. The stroke is an index of fluidity.

[0069] (Evaluation of minimum melt viscosity retention over time) The coil sealing resin compositions of each of the Examples and Comparative Examples were used to evaluate the minimum melt viscosity retention over time. The coil sealing resin compositions were left at 25°C and a relative humidity of 50% for 24 hours, 48 ​​hours, 72 hours, 96 hours, and 120 hours, and the minimum melt viscosity at 130°C was measured. The minimum melt viscosity retention was calculated based on the following formula. Minimum melt viscosity retention rate = (minimum melt viscosity of the coil sealing resin composition after being left for a predetermined time / minimum melt viscosity of the coil sealing resin composition before being left for a predetermined time) x 100 The results are shown in Figure 1. The smaller the minimum melt viscosity retention rate, the smaller the change in minimum melt viscosity over time, meaning better storage stability.

[0070] (Gel time measurement) The gel time at 140° C. was measured using the coil sealing resin composition of each of the Examples and Comparative Examples. The gel time of the coil sealing resin composition was measured using a Curastometer (manufactured by JSR Trading Co., Ltd.) under the conditions of a sample amount of 1.5 ml and 140° C. The time at which the torque on the obtained chart started to rise was taken as the gel time (sec). The results are shown in Table 2 below.

[0071] (Evaluation of gel time over time) The gel time over time was evaluated using the coil sealing resin compositions of Examples 1 and 2 and Comparative Example 2. The gel time at 140°C was measured using the coil sealing resin compositions left at 25°C and a relative humidity of 50% for 24 hours, 48 ​​hours, 72 hours, 96 hours, and 120 hours, respectively, and the coil sealing resin compositions left at 30°C and a relative humidity of 70% for 12 hours, 24 hours, 48 ​​hours, and 72 hours, respectively. The gel time retention was calculated based on the following formula. Gel time retention rate = (gel time of the coil encapsulating resin composition after being left for a predetermined time / gel time of the coil encapsulating resin composition before being left for a predetermined time) x 100 The results are shown in Figures 2 to 4.

[0072] (High temperature bending test) Test pieces were obtained by transfer molding using the coil sealing resin compositions of each Example and Comparative Example at 140°C. The test pieces were rectangular parallelepipeds (bars) made of the cured products obtained by post-curing the coil sealing resin compositions at 180°C for 2 hours. The pressure applied to the compound was 13.5 MPa. The dimensions of the test pieces were 80 mm long x 10 mm wide x 3.0 mm thick. A three-point support bending test was performed on the test pieces using an autograph equipped with a thermostatic chamber. The autograph used was an AGS-500A manufactured by Shimadzu Corporation. The temperature of the thermostatic chamber was 250°C. In the bending test, one side of the test piece was supported by two supports. A load was applied to the center position between the two supports on the other side of the test piece. The load at which the test piece broke was measured. The measurement conditions for the bending test were as follows. Distance between two supports Lv: 64.0±0.5mm Head speed: 2.0±0.2mm / min Chart speed: 100mm / min Chart full scale: 490N(50kgf) The bending strength σ (unit: MPa) was calculated based on the following formula (A). The bending modulus E (unit: GPa) was calculated based on the following formula (B). In the formulas below, "P" is the load (unit: N) when the test piece breaks. "Lv" is the distance between the two supports (unit: mm). "W" is the width of the test piece (unit: mm). "t" is the thickness of the test piece (unit: mm). "F / Y" is the gradient of the straight line 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)

[0073] (Evaluation of elastic modulus and strength balance) From the viewpoint of reliability of coil sealing, it is desirable that the cured product of the resin composition for coil sealing has a low flexural modulus and a high flexural strength at high temperatures. Whether or not the balance between the flexural modulus and the flexural strength is excellent can be evaluated by the calculated value of the reliability index formula shown below. Reliability index = (flexural strength (MPa) ÷ flexural modulus (GPa)) The results are shown in Table 2. The calculated value of the reliability index formula can be evaluated as follows. Calculated value 10 x 10 -3 Less than...Poor balance between elastic modulus and strength. Calculated value 10 x 10 -3 11×10 or more -3 Below: Excellent balance of elastic modulus and strength. Calculated value 11 x 10 -3 Ultra-excellent balance of elastic modulus and strength.

[0074] [Table 2]

[0075] 1, the coil sealing resin compositions of Examples 1 and 2 had smaller minimum melt viscosity retention rates than the coil sealing resin compositions of Comparative Examples 1 and 2. Therefore, the coil sealing resin compositions of Examples 1 and 2 had small changes in minimum melt viscosity over time and were excellent in storage stability.

[0076] 2 to 4, the coil sealing resin compositions of Examples 1 and 2 had higher gel time retention values ​​than the coil sealing resin composition of Comparative Example 2. Therefore, the coil sealing resin compositions of Examples 1 and 2 had excellent storage stability.

[0077] As shown in Table 2, the molded products molded using the coil sealing resin compositions of Examples 1 and 2 had higher reliability index values ​​than the molded products molded using the coil sealing resin compositions of Comparative Examples 1 and 2. This shows that the use of the coil sealing resin compositions of Examples 1 and 2 allows for the production of molded products that are excellent in balance between flexural modulus and flexural strength at high temperatures and have high reliability.

[0078] The disclosure of Japanese Patent Application No. 2019-171448, filed on September 20, 2019, is incorporated herein by reference in its entirety. All publications, patent applications, and standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or standard was specifically and individually indicated to be incorporated by reference.

Claims

1. Magnetic powder; Epoxy resin, A hardener; a curing accelerator containing an inner salt of a phosphine having an aryl group; The coil sealing resin composition, wherein the inner salt of a phosphine having an aryl group is an inner salt of an anion and a cation having a triphenylphosphine skeleton, which includes a triphenylphosphine cation or a reaction product of triphenylphosphine and hydroquinone.

2. The coil sealing resin composition according to claim 1 , further comprising a mold release agent.

3. The coil sealing resin composition according to claim 1 , wherein a content of the magnetic powder is 60 mass % or more with respect to a total amount of the coil sealing resin composition.

4. A resin composition for coil sealing described in any one of claims 1 to 3, wherein the epoxy resin includes a biphenyl type epoxy resin and a bisphenol type epoxy resin.

5. A resin composition for coil sealing described in any one of claims 1 to 4, wherein the curing agent contains a biphenyl type phenolic resin and a triphenylmethane type phenolic resin.

6. An electronic component device comprising: a coil; and a cured product of the coil sealing resin composition according to any one of claims 1 to 5 that seals the coil.

7. A method for producing an electronic component device, comprising the step of encapsulating a coil with the coil encapsulating resin composition according to any one of claims 1 to 5.

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