Thermosetting resin composition, resin sheet, metal base substrate, and electronic device

Abstract

To provide a thermosetting resin composition which is usable for manufacturing a thermally conductive sheet having high thermal conductivity.SOLUTION: A thermosetting resin composition contains (A) an epoxy resin, (B) a thermosetting resin (excluding the epoxy resin (A), (C) a phenoxy resin, and (D) a thermally conductive filler, where the phenoxy resin (C) is a phenoxy resin obtained by reacting a bifunctional epoxy compound (c1) having two epoxy groups and a polyfunctional phenol compound (c2) having at least two phenolic hydroxyl groups.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a thermosetting resin composition, a resin sheet made of the thermosetting resin composition, an electronic device including a cured product of the resin sheet as a heat conductive sheet, a metal base substrate including a cured product of the resin sheet, and an electronic device including the metal base substrate.

Background Art

[0002] With the high integration of semiconductors and the rapid improvement of the processing capabilities of electronic devices, a large amount of heat is generated from high-performance electronic components. Therefore, heat countermeasures for effectively dissipating heat from electronic components to the outside have become a very important issue. As such heat dissipation countermeasures, heat conductive members made of heat dissipation materials such as metals, ceramics, and polymer compositions are applied to heat dissipation members such as printed wiring boards, semiconductor packages, housings, heat pipes, heat sinks, and heat diffusion plates.

[0003] Among these heat dissipation members, a heat conductive epoxy resin molded body formed from an epoxy resin composition is widely used mainly in the electrical and electronic fields as a cast product, a laminate, a sealing material, a heat conductive sheet, an adhesive, etc., because it is excellent in electrical insulation, mechanical properties, heat resistance, chemical resistance, adhesiveness, etc.

[0004] As a technology of this kind, for example, Patent Document 1 proposes a heat conductive epoxy resin composition and a molded body thereof in which flaky or spherical boron nitride particles as heat conductive particles are blended with a bisphenol A type epoxy resin as an epoxy resin. In addition, it has also been proposed to improve the thermal conductivity and heat resistance of the epoxy resin itself (for example, Patent Document 2). In Patent Document 2, an insulating composition with improved thermal conductivity is obtained by polymerizing a liquid crystalline epoxy resin having a mesogenic group or the like.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] However, as a result of investigations by the present inventor, it has been found that conventional resin compositions have room for further improvement in terms of thermal conductivity. [Means for Solving the Problems]

[0007] The present invention has been made in view of the above problems, and has found that a novel phenoxy resin having a specific structure has high thermal conductivity, thereby completing the present invention.

[0008] According to the present invention, (A) an epoxy resin, (B) a thermosetting resin (excluding the epoxy resin (A)), (C) a phenoxy resin, (D) a thermal conductivity filler, and a thermosetting resin composition, wherein the phenoxy resin (C) is a phenoxy resin obtained by reacting a bifunctional epoxy compound (c1) having two epoxy groups with a polyfunctional phenol compound (c2) having at least two phenolic hydroxyl groups, the bifunctional epoxy compound (c1) contains a compound represented by the formula (d-EP),

[0009] [Chemical Formula]

[0010] X in the formula (d-EP) is a divalent group having a mesogenic skeleton, the polyfunctional phenol compound (c2) is at least one selected from the compounds represented by the formulas (p1) to (p8),

[0011]

Chem.

[0012]

Chem.

[0013] In the above formulas (p1) to (p8), R 11 and R 12 each independently represent a hydrogen atom, an alkoxy group having 1 to 4 carbon atoms, or a linear or branched alkyl group having 1 to 4 carbon atoms, and a thermosetting resin composition is provided.

[0014] Further, according to the present invention, a resin sheet comprising the above thermosetting resin composition is provided.

[0015] Further, according to the present invention, a heat generating member, a heat radiating member, and a thermally conductive sheet provided between the heat generating member and the heat radiating member, and an electronic device comprising the same is provided, wherein the thermally conductive sheet is made of a cured product of the above resin sheet, and an electronic device is provided.

[0016] Further, according to the present invention, a metal substrate, a thermally conductive sheet, and a metal layer, in this order, and a metal base substrate comprising the same is provided, wherein the thermally conductive sheet is made of a cured product of the above resin sheet, and a metal base substrate is provided.

[0017] Furthermore, according to the present invention, an electronic device comprising the above metal base substrate is provided.

Advantages of the Invention

[0018] According to the present invention, a thermosetting resin composition that can be used for manufacturing a thermally conductive sheet having high thermal conductivity is provided.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Mode for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and the description will be omitted as appropriate. Also, "~" represents "from... to..." unless otherwise specified.

[0021] [Thermosetting Resin Composition] The thermosetting resin composition of this embodiment contains the following components (A) to (D). (A) An epoxy resin, and (B) A thermosetting resin (excluding the epoxy resin (A)), and (C) A phenoxy resin, and (D) A thermally conductive filler. By having the above composition, the thermosetting resin composition of this embodiment has high thermal conductivity and can be suitably used, for example, as a thermal conductive sheet for an electronic device.

[0022] Hereinafter, the components used in the thermosetting resin composition of this embodiment will be described.

[0023] (Epoxy Resin (A)) The thermosetting resin composition of this embodiment contains an epoxy resin (A). Examples of the epoxy resin (A) include glycidyl ethers such as bisphenol A type, F type, S type, and AD type, glycidyl ether of hydrogenated bisphenol A type, glycidyl ether of phenol novolak type, glycidyl ether of cresol novolak type, glycidyl ether of novolak type of bisphenol A type, glycidyl ether of naphthalene type, glycidyl ether of biphenol type, glycidyl ether of dihydroxypentadiene type, triphenylmethane type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, and glycidyl ether of hydroquinone type. At least one kind can be used. From the viewpoint of the effects of the present invention, the epoxy resin (A) preferably contains at least one selected from glycidyl ethers of naphthalene type, glycidyl ethers of biphenol type, glycidyl ethers of dihydroxypentadiene type, and glycidyl ethers of hydroquinone type.

[0024] The epoxy resin (A) can preferably contain an epoxy resin containing a mesogenic skeleton. Thereby, the thermal conductivity (heat dissipation property) of the resin cured product can be further enhanced. It is considered that the epoxy resin containing a mesogenic skeleton forms a higher-order structure (liquid crystal phase or crystal phase) by the mesogenic skeleton during curing. And it is considered that the thermal conductivity (heat dissipation property) is further increased by the heat being transmitted through the higher-order structure. The presence of the higher-order structure in the cured product can be confirmed by observation with a polarized light microscope.

[0025] Examples of the mesogenic skeleton include all skeletons that are likely to exhibit liquid crystallinity or crystallinity due to the action of intermolecular interaction. The mesogenic skeleton preferably contains a conjugated structure. Specific examples of the mesogenic skeleton include a biphenyl skeleton, a phenylbenzoate skeleton, an azobenzene skeleton, a stilbene skeleton, a naphthalene skeleton, an anthracene skeleton, a chalcone skeleton, and a phenanthrene skeleton.

[0026] The epoxy resin (A) particularly preferably contains a condensed polycyclic aromatic hydrocarbon skeleton, and most preferably contains a naphthalene skeleton.

[0027] Here, for example, in the biphenyl skeleton (-C6H4-C6H4-), at high temperatures, due to thermal motion, the carbon-carbon single bond part at the center of the above structure may "rotate", and the liquid crystallinity may decrease. Similarly, in the phenyl benzoate skeleton (-C6H4-COO-C6H4-), the ester bond may rotate at high temperatures. However, in a condensed polycyclic aromatic hydrocarbon skeleton such as a naphthalene skeleton, in principle, there is no decrease in liquid crystallinity due to such rotation. That is, by the epoxy resin containing a condensed polycyclic aromatic hydrocarbon skeleton, the heat dissipation property of the obtained resin cured product under a high-temperature environment can be further enhanced.

[0028] Also, by particularly adopting a naphthalene skeleton as the polycyclic aromatic hydrocarbon skeleton, while obtaining the above merits, it is also possible to suppress the epoxy resin from becoming too rigid. This is because the naphthalene skeleton is relatively small as a mesogen skeleton. The fact that the epoxy resin does not become too rigid is preferable in terms of suppressing cracks and the like due to the stress during curing of the thermosetting resin composition of the present embodiment being easily relaxed.

[0029] The epoxy resin (A) preferably contains a bifunctional or higher epoxy resin. That is, it is preferable that two or more epoxy groups are contained in one molecule of the epoxy resin. The functional group number of the epoxy resin is preferably 2 to 6, more preferably 2 to 4. From the viewpoint of the effects of the present invention, the epoxy resin (A) in the present embodiment preferably contains at least one epoxy resin selected from the compounds represented by the following formula.

[0030]

Chemical formula

[0031] The epoxy equivalent of the epoxy resin (A) is, for example, 100 to 200 g / eq, preferably 105 to 190 g / eq, more preferably 110 to 180 g / eq. By using an epoxy resin having an appropriate epoxy equivalent, it is possible to control the curability and optimize the physical properties of the cured product.

[0032] In one embodiment, the epoxy resin (A) preferably further contains another epoxy resin that is liquid or semi-solid at room temperature (23°C). Specifically, part or all of the epoxy resin is preferably liquid or semi-solid at 23°C. By using a liquid or semi-solid epoxy resin, it becomes easier to form a cured product having a desired shape.

[0033] In one embodiment, the epoxy resin (A) preferably contains a combination of a liquid epoxy resin at room temperature and a semi-solid or solid epoxy resin at room temperature. Thereby, the moldability of the obtained thermosetting resin composition is improved.

[0034] The epoxy resin (A) is, for example, 5% to 40% by mass, preferably 7% to 35% by mass, more preferably 10% to 30% by mass, based on the resin component (100% by mass) of the thermosetting resin composition that does not contain the thermally conductive particles (D). Thereby, sufficient curability can be ensured, and a resin sheet excellent in high thermal conductivity and insulation can be obtained.

[0035] (Thermosetting resin (B)) The thermosetting resin composition of the present embodiment contains a thermosetting resin (B). Here, the thermosetting resin (B) does not contain the above-described epoxy resin (A). Examples of the thermosetting resin (B) include a thermosetting compound containing a mesogenic structure (mesogenic skeleton) in the molecule and a thermosetting compound not containing a mesogenic structure in the molecule.

[0036] Examples of the thermosetting resin (B) include cyanate resins, maleimide resins, phenol resins, benzoxazine resins, polyimide resins, unsaturated polyester resins, melamine resins, silicone resins, acrylic resins, and phenol derivatives and their derivatives, etc., and at least one kind can be included.

[0037] In this embodiment, the thermosetting resin (B) preferably contains at least one selected from cyanate resins, bismaleimide resins, phenol resins, and benzoxazine resins, and more preferably contains a cyanate resin. For these thermosetting resins, monomers, oligomers, and polymers in general having two or more reactive functional groups in one molecule can be used, and their molecular weight and molecular structure are not particularly limited.

[0038] <Cyanate resin> As the cyanate resin, those known within the scope where the effects of the present invention are achieved can be used. Examples of the cyanate resin include novolak type cyanate resins; bisphenol type cyanate resins such as bisphenol A type cyanate resin, bisphenol E type cyanate resin, and tetramethyl bisphenol F type cyanate resin; naphthol aralkyl type cyanate resin obtained by the reaction of naphthol aralkyl type phenol resin and cyanogen halide; dicyclopentadiene type cyanate resin; and biphenylene skeleton-containing phenol aralkyl type cyanate resin. One or more selected from these can be included. Among these, from the viewpoint of the effects of the present invention, it is more preferable to contain at least one of novolak type cyanate resin and naphthol aralkyl type cyanate resin, and it is particularly preferable to contain novolak type cyanate resin.

[0039] As the novolak type cyanate resin, for example, those represented by the following general formula (I) can be used.

[0040]

Chemical formula

[0041] The average repeating unit n of the novolak type cyanate resin represented by the general formula (I) is an arbitrary integer. The average repeating unit n is not particularly limited, but is preferably 1 or more, more preferably 2 or more. When the average repeating unit n is at least the above lower limit value, the heat resistance of the novolak type cyanate resin is improved, and the elimination and volatilization of the oligomer during heating can be further suppressed. Further, the average repeating unit n is not particularly limited, but is preferably 10 or less, more preferably 7 or less. When n is at most the above upper limit value, an increase in the melt viscosity can be suppressed, and the moldability of the resin sheet can be improved.

[0042] Further, as the cyanate resin, a naphthol aralkyl type cyanate resin represented by the following general formula (II) is also preferably used. The naphthol aralkyl type cyanate resin represented by the following general formula (II) is obtained, for example, by condensing a naphthol aralkyl type phenol resin obtained by reacting naphthols such as α-naphthol or β-naphthol with p-xylylene glycol, α,α'-dimethoxy-p-xylene, 1,4-di(2-hydroxy-2-propyl)benzene, etc. with a cyanogen halide. The repeating unit n of the general formula (II) is preferably an integer of 10 or less. When the repeating unit n is 10 or less, a more uniform resin sheet can be obtained. Further, intramolecular polymerization is less likely to occur during synthesis, the liquid separation property during water washing is improved, and there is a tendency to prevent a decrease in the yield.

[0043]

Chemical formula

[0044] In the above general formula (II), each R independently represents a hydrogen atom or a methyl group, and n represents an integer of 1 or more and 10 or less.

[0045] The cyanate resin is, for example, 10% by mass to 70% by mass, preferably 15% by mass to 60% by mass, more preferably 20% by mass to 50% by mass, based on 100% by mass of the resin component of the thermosetting resin composition that does not contain the thermally conductive particles (D). Thereby, sufficient curability can be ensured, and a resin sheet excellent in higher thermal conductivity and insulation can be obtained.

[0046] <Maleimide resin> As the maleimide resin, for example, a maleimide resin having at least two maleimide groups in the molecule is preferable.

[0047] Examples of the maleimide resin having at least two maleimide groups in the molecule include 4,4'-diphenylmethane bismaleimide, m-phenylene bismaleimide, p-phenylene bismaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, bis-(3-ethyl-5-methyl-4-maleimidophenyl)methane, 4-methyl-1,3-phenylene bismaleimide, N,N'-ethylenedimaleimide, N,N'-hexamethylenedimaleimide, bis(4-maleimidophenyl)ether, bis(4-maleimidophenyl)sulfone, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethane bismaleimide, resins having two maleimide groups in the molecule such as bisphenol A diphenyl ether bismaleimide, biphenyl aralkyl type maleimide, resins having three or more maleimide groups in the molecule such as polyphenylmethane maleimide, and the like.

[0048] <Phenolic resin> Examples of the phenolic resin include novolak type phenolic resins such as phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, and resol type phenolic resins. One of these may be used alone, or two or more thereof may be used in combination. Among the phenolic resins, it is preferable to use phenol novolak resin.

[0049] <Benzoxazine resin> Specific examples of the benzoxazine resin include o-cresol aniline type benzoxazine resin, m-cresol aniline type benzoxazine resin, p-cresol aniline type benzoxazine resin, phenol-aniline type benzoxazine resin, phenol-methylamine type benzoxazine resin, phenol-cyclohexylamine type benzoxazine resin, phenol-m-toluidine type benzoxazine resin, phenol-3,5-dimethylaniline type benzoxazine resin, bisphenol A-aniline type benzoxazine resin, bisphenol A-amine type benzoxazine resin, bisphenol F-aniline ... Examples of the benzoxazine resin include aniline type benzoxazine resin, bisphenol S-aniline type benzoxazine resin, dihydroxydiphenylsulfone-aniline type benzoxazine resin, dihydroxydiphenylether-aniline type benzoxazine resin, benzophenone type benzoxazine resin, biphenyl type benzoxazine resin, bisphenol AF-aniline type benzoxazine resin, bisphenol A-methylaniline type benzoxazine resin, phenol-diaminodiphenylmethane type benzoxazine resin, triphenylmethane type benzoxazine resin, and phenolphthalein type benzoxazine resin.

[0050] From the viewpoint of the effects of the present invention, the content of the thermosetting resin (B) is, for example, preferably 0.1 mass % to 70 mass %, more preferably 0.5 mass % to 65 mass %, and even more preferably 1 mass % to 60 mass %, relative to the resin component (100 mass %) of the thermosetting resin composition not including the thermally conductive particles (D).

[0051] (Phenoxy resin (C)) The thermosetting resin composition of the present embodiment contains a phenoxy resin (C). The phenoxy resin (C) is A bifunctional epoxy compound (c1) having two epoxy groups represented by the formula (d-EP), and a polyfunctional phenol compound (c2) having at least two phenolic hydroxyl groups. More specifically, the phenoxy resin (C) is a polymer obtained by the reaction of the epoxy groups of the bifunctional epoxy compound (c1) and the phenolic hydroxyl groups of the polyfunctional phenol compound (c2) to form a crosslinked structure. That is, the phenoxy resin (C) used in this embodiment is a phenoxy resin containing a structural unit derived from the bifunctional epoxy compound (c1) and a structural unit derived from the polyfunctional phenol compound (c2).

[0052] The bifunctional epoxy compound (c1) constituting the phenoxy resin (C) used in this embodiment includes a compound represented by the formula (d-EP).

[0053] [Chemical formula]

[0054] X in the formula (d-EP) is a divalent group having a mesogenic skeleton. The phenoxy resin (C) used in the thermosetting resin composition of this embodiment contains a structural unit derived from the epoxy compound (c1) having a mesogenic skeleton, so that the cured product has high thermal conductivity and high heat resistance.

[0055] Examples of the mesogenic skeleton of the X group in the formula (d-EP) include a biphenyl skeleton, a naphthalene skeleton, a phenylbenzoate skeleton, an azobenzene skeleton, a stilbene skeleton, a cyclohexylbenzene skeleton, and derivatives thereof. When the X group has the above mesogenic skeleton, the phenoxy resin (C) can have high thermal conductivity.

[0056] In one embodiment, at least one of the X groups of the formula (d-EP) is a group represented by the formula (2). By including a structure having a mesogenic skeleton represented by the formula (2), the phenoxy resin (C) has high thermal conductivity and excellent heat resistance. Therefore, the thermosetting resin of this embodiment containing the same can have high thermal conductivity.

[0057] [Chemical formula]

[0058] In one embodiment, the group represented by formula (2) is preferably a group in which R1, R4, R5, and R8 are alkyl groups having 1 to 4 carbon atoms and R2, R3, R6, and R7 are hydrogen atoms. Among them, a group in which R1, R4, R5, and R8 in formula (2) are alkyl groups having 1 carbon atom and R2, R3, R6, and R7 are hydrogen atoms (referred to as a "tetramethylbiphenyl group") is preferable in that it can achieve an excellent balance between the thermal conductivity and heat resistance of the resulting phenoxy resin (C).

[0059] In one embodiment, the group represented by formula (2) may be a group in which R1, R4, R5, and R8 are alkyl groups having 1 carbon atom and R2, R3, R6, and R7 are hydrogen atoms (referred to as a "biphenyl group"). By having such a group, the phenoxy resin (C) has excellent thermal conductivity and heat resistance.

[0060] In one embodiment, formula (d-EP) preferably contains a tetramethylbiphenyl group and a biphenyl group as the X group. The phenoxy resin (C) containing these groups in combination can have an excellent balance between thermal conductivity and heat resistance.

[0061] The polyfunctional phenol compound (c2) constituting the crosslinked structure of the phenoxy resin (C) used in the present embodiment is a phenol compound having at least two phenolic hydroxyl groups, preferably a bifunctional phenol compound having two phenolic hydroxyl groups or a trifunctional phenol compound having three phenolic hydroxyl groups, and specifically, is at least one selected from the compounds represented by formulas (p1) to (p8).

[0062] [Chemical formula]

[0063] [Chemical formula]

[0064] In the above formulas (p1) to (p8), R 11 and R 12 each independently represents a hydrogen atom, an alkoxy group having 1 to 4 carbon atoms, or a linear or branched alkyl group having 1 to 4 carbon atoms. By containing a structural unit derived from the compound represented by the formulas (p1) to (p8), the phenoxy resin (C) can endow the thermosetting resin composition containing the same with high thermal conductivity. In this embodiment, the polyfunctional phenol compound having a flavanone skeleton represented by the formulas (P3), (p4), (p7) and (p8) includes stereoisomers. Specifically, the isoflavanone compounds of the formulas (p3) and (p7) include stereoisomers in which the C2 carbon is an asymmetric carbon atom, and the isoflavanone compounds of the formulas (p4) and (p8) include stereoisomers in which the C3 atom is an asymmetric carbon atom.

[0065] In one embodiment, all of R 11 and R 12 in the compounds represented by the formulas (p1) to (p8) are hydrogen atoms. The phenoxy resin (C) having a structural unit derived from the polyfunctional phenol compound (c2) having such a structure can have high thermal conductivity and heat resistance. As a result, the cured product obtained from the thermosetting resin composition containing the phenoxy resin (C) has high thermal conductivity.

[0066] The phenoxy resin (C) used in this embodiment may contain structural units derived from other components (c3) in addition to the bifunctional epoxy compound (c1) and the polyfunctional phenol compound (c2), as long as the properties of the phenoxy resin are not affected. Examples of the component (c3) include, but are not limited to, glycidyl ester type epoxy compounds, glycidyl amine type epoxy compounds, alicyclic epoxy compounds, Bis-A type epoxy compounds, Bis-E type epoxy compounds, Bis-F type epoxy compounds, Bis-S type epoxy compounds, and bisphenol compounds which are precursors thereof. When the phenoxy resin (C) contains structural units derived from the component (c3), the content thereof is, for example, 10 mol% or less, preferably 5 mol% or less, based on all the structural units constituting the phenoxy resin (C).

[0067] In one embodiment, the phenoxy resin (C) is a resin having a structure represented by the following (1), which is obtained by reacting a bifunctional epoxy compound represented by the above formula (d-EP) with at least one selected from the bifunctional phenol compounds represented by the above formulas (p1) to (p4).

Chemical formula

[0068] In formula (1), n represents the number of repeating units and represents an integer of 2 to 50, preferably an integer of 5 to 40, more preferably an integer of 6 to 30, and even more preferably an integer of 8 to 20. X has the same meaning as X in the above formula (d-EP). Y is independently at least one divalent group selected from the following formulas (y1) to (y4).

[0069]

Chemical formula

[0070]

Chemical formula

[0071] In formulas (y1) to (y4), R 11 and R 12 each independently represents a hydrogen atom, an alkoxy group having 1 to 4 carbon atoms, or a linear or branched alkyl group having 1 to 4 carbon atoms, and * represents the linking position. Note that the groups of formulas (y1) to (y4) are each a group derived from the polyfunctional phenol compound (c2) of formulas (p1) to (p4).

[0072] The phenoxy resin (C) having the structure represented by formula (1) of the present embodiment has, in its structure, a divalent organic group having a mesogenic skeleton represented as "X" in formula (1), and at least one divalent group selected from formula (y1) having an isoflavonoid skeleton, formula (y2) having a flavonoid skeleton, formula (y3) having a flavanone skeleton, and formula (y4) represented as "Y" in formula (1). By having such a structure, the cured product of the thermosetting resin composition containing the phenoxy resin (C) has high thermal conductivity.

[0073] In addition to the above-described X group and Y group, the phenoxy resin (C) represented by formula (1) may contain other groups as long as they do not affect the properties of the phenoxy resin.

[0074] The weight average molecular weight (Mw) of the phenoxy resin (C) used in the present embodiment is, for example, 1,000 to 10,000, preferably 2,000 to 8,000, more preferably 3,000 to 7,000, and even more preferably 3,500 to 6,500. Mw is measured by gel permeation chromatography and represents a value converted using a standard polystyrene calibration curve. By setting Mw within the above range, the thermal conductivity of the phenoxy resin (C) can be further improved.

[0075] In this embodiment, the weight-average molecular weight (Mw) of the phenoxy resin (C) can be measured by obtaining a molecular weight distribution curve using GPC (Gel Permeation Chromatography). The weight-average molecular weight (Mw), number-average molecular weight (Mn), and dispersity (PDI: Mw / Mn) of the phenoxy resin are calculated using the polystyrene conversion values determined from the calibration curve of standard polystyrene (PS) obtained by GPC measurement.

[0076] The measurement conditions of GPC are as follows, for example. Gel Permeation Chromatography device HLC-8320GPC manufactured by Tosoh Corporation Column: TSK-GEL GMH, G2000H, SuperHM-M manufactured by Tosoh Corporation Detector: RI detector for liquid chromatogram Measurement temperature: 40 °C Solvent: THF Sample concentration: 2.0 mg / mL

[0077] The dispersity (Mw / Mn) of the phenoxy resin (C) is, for example, from 1.00 to 7.00, preferably from 2.00 to 6.00, and more preferably from 3.50 to 5.50. By setting the dispersity within the above range, the thermal conductivity and fluidity of the phenoxy resin (C) can be further improved.

[0078] The phenoxy resin (C) may contain a low-molecular-weight phenoxy resin having a weight-average molecular weight (Mw) of 1000 or less. When the phenoxy resin contains a low-molecular-weight phenoxy resin, the low-molecular-weight phenoxy resin is, for example, in an amount of 5% or more and 60% or less, preferably 5% or more and 50% or less, as the ratio of the total area of the components corresponding to a weight-average molecular weight Mw of 1000 or less to the total area of 100% of the entire molecular weight distribution obtained by GPC measurement. The phenoxy resin containing the low-molecular-weight phenoxy resin in the above range of amounts has improved fluidity and excellent handleability. Therefore, for example, the processing stability when processing the resin composition of this embodiment into the form of a sheet or film is improved.

[0079] From the viewpoint of the effects of the present invention, the epoxy equivalent of the phenoxy resin (C) is, for example, 300 to 6,000 g / eq, preferably 350 to 5,000 g / eq, and more preferably 400 to 4,500 g / eq.

[0080] By having the above-mentioned specific configuration, the phenoxy resin (C) can improve the thermal conductivity of its cured product. The thermal conductivity of the cured product of the phenoxy resin (C) is, for example, 0.3 W / (m·K) or more, preferably 0.35 W / (m·K) or more, and more preferably 0.4 W / (m·K) or more. Since the phenoxy resin (C) itself has high thermal conductivity, the cured product of the thermosetting resin composition containing this can also have high thermal conductivity.

[0081] By having the above-mentioned specific structure, the cured product of the phenoxy resin (C) has a high 1% weight loss temperature. The 1% weight loss temperature of the cured product of the phenoxy resin (C) is 300°C or more, preferably 310°C or more, more preferably 320°C or more, and even more preferably 330°C or more. The upper limit value of the 1% weight loss temperature of the cured product of the phenoxy resin (C) is, for example, 400°C or less.

[0082] (Production of Phenoxy Resin (C)) The phenoxy resin (C) used in the present embodiment can be synthesized by reacting a bifunctional epoxy compound (c1) represented by the above formula (d-EP) with at least one of the polyfunctional phenol compounds (c2) represented by the above formulas (p1) to (p8). In addition, within a range not impairing the effects of the present invention, the phenoxy resin (C) may be synthesized using the above-mentioned component (c3) in addition to these bifunctional epoxy compound (c1) and polyfunctional phenol compound (c2).

[0083] The above reaction can be carried out using a reaction catalyst in the absence of a solvent or in the presence of a reaction solvent.

[0084] As the reaction solvent that can be used, aprotic organic solvents such as methyl ethyl ketone, dioxane, tetrahydrofuran, acetophenone, N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylacetamide, sulfolane, propylene glycol monomethyl ether, cyclohexanone, etc. can be preferably used. By using a reaction solvent, the initial viscosity can be reduced and the reactivity of the monomer is improved.

[0085] As the above reaction catalyst, conventionally known polymerization catalysts can be used, and alkali metal hydroxides, tertiary amine compounds, quaternary ammonium compounds, tertiary phosphine compounds, and quaternary phosphonium compounds, imidazole compounds are preferably used.

[0086] Specifically, a bifunctional epoxy compound (c1), a polyfunctional phenol compound (c2), a reaction catalyst, and, if necessary, a reaction solvent are added and melt-mixed with stirring. The heating temperature during melt-mixing is about 90 to 120 °C, the mixing time is about 30 minutes to 2 hours, and the reaction pressure is carried out at normal pressure. After melt-mixing, the temperature of the mixed solution is raised, and a polymerization reaction is carried out under reduced pressure or normal pressure at a predetermined reaction temperature. The reaction temperature is about 140 to 180 °C, the reaction time is about 2 hours to 10 hours, and the reaction pressure is carried out at about 1 to 760 Torr.

[0087] After completion of the reaction, it is possible to obtain a resin dissolved in a suitable solvent by performing solvent substitution or the like. Further, the phenoxy resin (C) obtained by the solvent reaction can also be obtained as a solid resin containing no solvent by performing a solvent removal treatment using an evaporator or the like.

[0088] In the above synthesis method, a phenoxy resin having a desired weight average molecular weight can be obtained by appropriately selecting reaction conditions such as the usage amount of starting materials, reaction temperature, and reaction time to adjust the degree of polymerization.

[0089] Examples of the bifunctional epoxy compound (c1) used for synthesizing the phenoxy resin (C) include 4,4'-diglycidyl biphenyl, 4,4'-diglycidyl-3,3',5,5'-tetramethyl biphenyl, and the like.

[0090] Examples of the polyfunctional phenol compound (c2) used for synthesizing the phenoxy resin (C) include flavones such as luteolin, apigenin, baicalein, scutellarein, tricetin, diosmetin, and nobilitin; isoflavonoids such as daidzein and genistein; and flavanones such as naringenin, butin, eriodictyol, hesperetin, homoeriodictyol, isosakuranetin, pinobanksin, sakuranetin, and sterbin. Among them, daidzein, genistein, and naringenin are preferably used because of their good handleability and the high thermal conductivity of the resulting phenoxy resin.

[0091] (Thermally Conductive Filler (D)) The thermosetting resin composition of this embodiment contains thermally conductive particles (D). The thermally conductive particles (D) can include, for example, high thermally conductive inorganic particles having a thermal conductivity of 20 W / m·K or more. Examples of the high thermally conductive inorganic particles can include at least one selected from silica, alumina, aluminum nitride, boron nitride, silicon nitride, silicon carbide, and magnesium oxide. These can be used alone or in combination of two or more.

[0092] The boron nitride can include monodisperse particles, aggregated particles, or a mixture thereof of flaky boron nitride. The flaky boron nitride may be granulated into granules. By using the aggregated particles of flaky boron nitride, the thermal conductivity can be further enhanced. The aggregated particles may be sintered particles or non-sintered particles.

[0093] The thermally conductive particles (D) (100% by mass) can contain 60% by mass or more, preferably 65% by mass or more, more preferably 70% by mass or more of the boron nitride. The upper limit is not particularly limited, but can be 100% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less.

[0094] The content of the thermally conductive particles (D) is 100% by mass to 400% by mass, preferably 150% by mass to 350% by mass, more preferably 200% by mass to 330% by mass with respect to the resin component (100% by mass) of the thermosetting resin composition. By setting it to be not less than the lower limit value, the thermal conductivity can be improved. By setting it to be not more than the upper limit value, a decrease in processability can be suppressed.

[0095] (Curing accelerator) The thermosetting resin composition of the present embodiment can contain a curing accelerator as needed. The type and blending amount of the curing accelerator are not particularly limited, but appropriate ones can be selected from the viewpoints of reaction rate, reaction temperature, storage stability, etc.

[0096] Examples of the curing accelerator include imidazoles, organic phosphorus compounds, tertiary amines, phenol compounds, organic acids, etc. These can be used alone or in combination of two or more. Among these, from the viewpoint of enhancing heat resistance, it is preferable to use nitrogen atom-containing compounds such as imidazoles.

[0097] Examples of the imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 2,4-diethylimidazole, 2-phenyl-4-methyl-5-hydroxyimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, etc.

[0098] Examples of the tertiary amines include triethylamine, tributylamine, 1,4-diazabicyclo[2.2.2]octane, 1,8-diazabicyclo(5,4,0)undecene-7, and the like.

[0099] Examples of the phenolic compound include phenolic resin, bisphenol A, nonylphenol, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, allylphenol, and the like. Examples of the organic acid include acetic acid, benzoic acid, salicylic acid, p-toluenesulfonic acid, and the like.

[0100] The content of the curing accelerator may be 0.01% by mass to 10% by mass, 0.02% by mass to 5% by mass, or 0.05% by mass to 1.5% by mass with respect to 100% by mass of the total amount of the thermosetting resin.

[0101] (Silane coupling agent) The above thermosetting resin composition may contain a silane coupling agent. Thereby, the compatibility of the thermally conductive filler in the thermosetting resin composition can be improved. The coupling agent may be added to the thermosetting resin composition or used after being treated on the surface of the thermally conductive filler.

[0102] (Other additives) The thermosetting resin composition of the present embodiment may contain components other than the above-described components. Examples of such other components include an antioxidant and a leveling agent.

[0103] [Manufacturing method of thermosetting resin composition] For example, the thermosetting resin composition of the present embodiment can be adjusted to a resin varnish (varnish-like thermosetting resin composition) by dissolving, mixing, and stirring each of the above components other than the thermally conductive filler in a solvent. For this mixing, various mixers such as an ultrasonic dispersion method, a high-pressure collision dispersion method, a high-speed rotation dispersion method, a bead mill method, a high-speed shear dispersion method, and a rotation-revolution dispersion method can be used.

[0104] Although there is no particular limitation on the solvent, examples thereof include acetone, methyl isobutyl ketone, toluene, ethyl acetate, cyclohexane, heptane, cyclohexanone, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ethylene glycol, cellosolve-based solvents, carbitol-based solvents, anisole, and N-methylpyrrolidone.

[0105] By adding a thermally conductive filler to the resin varnish and kneading it using a three-roll mill or the like, a thermosetting resin composition in a B-stage state can be obtained. By adding it during kneading, it is possible to disperse the inorganic filler more uniformly in the thermosetting resin, but it is not limited thereto. The thermally conductive filler may be added during kneading or may be added during mixing of the resin varnish. From the viewpoint of dispersibility, it is preferable to add nanoparticles, for example, those dispersed in a predetermined solvent (nanoparticle dispersion) into the resin varnish. After kneading, it may be cooled and solidified, and the kneaded product may be processed into a granular, tablet, or sheet form.

[0106] [Resin Sheet] The resin sheet of the present embodiment is formed by curing the thermosetting resin composition. The specific form of the resin sheet includes a carrier substrate and a resin layer made of the thermosetting resin composition of the present embodiment provided on the carrier substrate.

[0107] The resin sheet can be obtained, for example, by performing a solvent removal treatment on a coating film (resin layer) obtained by applying a varnish-like thermosetting resin composition on a carrier substrate. The solvent content in the resin sheet can be 10% by mass or less with respect to the entire thermosetting resin composition. For example, the solvent removal treatment can be performed under the conditions of 80°C to 200°C for 1 minute to 30 minutes.

[0108] The resin sheet (resin layer) of the present embodiment is in a B-stage state, and a thermosetting resin composition that does not contain thermally conductive particles (D) serving as a binder preferably has the following curing behavior. Specifically, a heat-curable resin composition containing no thermally conductive particles (D) is pre-dried at 115°C for 12 minutes to create a sheet in the B-stage state, and using a cone-plate type rheometer, at a measurement temperature of 180°C, the curing torque of the sheet in the B-stage state is measured over time. The time T required from the start of measurement to the maximum torque max When it is 50 the ratio of the time T 50 to reach the value of 50% of the maximum torque value from the start of measurement max is preferably 0.1 to 1.0, more preferably 0.2 to 0.8, and even more preferably 0.25 to 0.75.

[0109] As the cone-plate type rheometer, for example, a rheometer "MCR-301" manufactured by Anton Paar can be used. Also, the frequency during measurement can be 1 Hz and the oscillation angle can be 1%. Since the curing behavior (ratio (T 50 / T max )) of the heat-curable resin composition without the filler of the present embodiment is within the above range, the cycle time during pressing can be maintained within an appropriate range, and the occurrence of molding defects such as voids can be suppressed, so the productivity of a metal base substrate or the like described later is improved.

[0110] In the present embodiment, as the carrier substrate, for example, a polymer film, a metal foil, or the like can be used. The polymer film is not particularly limited, and examples include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, release papers such as polycarbonate and silicone sheets, fluorine-based resins, and heat-resistant thermoplastic resin sheets such as polyimide resins. The metal foil is not particularly limited, and examples include copper and / or copper-based alloys, aluminum and / or aluminum-based alloys, iron and / or iron-based alloys, silver and / or silver-based alloys, gold and gold-based alloys, zinc and zinc-based alloys, nickel and nickel-based alloys, tin and tin-based alloys, and the like.

[0111] The resin substrate of this embodiment includes an insulating layer composed of a cured product of the above thermosetting resin composition. This resin substrate can be used as a material for a printed circuit board for mounting electronic components such as LEDs and power modules.

[0112] [Electronic device] The cured product of the resin sheet is used as a heat-conductive sheet interposed between a heat-generating body and a heat radiator.

[0113] Examples of the heat-generating body include semiconductor elements, LED elements, substrates on which semiconductor elements or LED elements are mounted, Central Processing Unit (CPU), power semiconductors, lithium-ion batteries, and fuel cells. Examples of the heat radiator include heat sinks, heat spreaders, and heat dissipation (cooling) fins. The heat dissipation and insulation member only needs to be partially composed of the thermosetting resin composition of this embodiment. Specifically, examples include a heat dissipation sheet formed by curing the thermosetting resin composition, a laminate in which the heat dissipation sheet and a substrate are laminated (for example, the metal base substrate 100 in FIG. 1), and the like. The substrate is not particularly limited as long as it is a heat-dissipating metal substrate. For example, it can be a copper substrate, a copper alloy substrate, an aluminum substrate, or an aluminum alloy substrate. A copper substrate or an aluminum substrate is preferred, and a copper substrate is more preferred. By using a copper substrate or an aluminum substrate, the heat dissipation property of the heat dissipation and insulation member can be made good. The heat dissipation and insulation member is partially composed of the thermosetting resin composition of this embodiment, and its thermal conductivity is preferably 12 W / m·K or more, more preferably 15 W / m·K or more. The heat dissipation and insulation member and the heat radiator may be formed on one side of the heat-generating body or on both sides. Also, various base materials and layers may be provided between the heat-generating body and the heat dissipation and insulation member or between the heat dissipation and insulation member and the heat radiator as long as it does not affect heat dissipation.

[0114] In the present embodiment, the heating element, the heat-radiating insulating member, and the heat sink can be appropriately combined from the above-described components to obtain a laminated structure. The laminated structure can be used for various applications that require heat-radiating insulation, and can be used for various applications such as semiconductor devices, smartphones, LED bulbs / lights, power modules, lithium-ion batteries, fuel cells, wireless base stations, and uninterruptible power supply devices. Hereinafter, the components included in the thermosetting resin composition of the present embodiment will be described.

[0115] [Metal base substrate] The metal base substrate (heat-radiating resin member) 100 of the present embodiment will be described with reference to FIG. 1. FIG. 1 is a schematic cross-sectional view showing an example of the configuration of the metal base substrate 100.

[0116] As shown in FIG. 1, the metal base substrate 100 can include a metal substrate 101, an insulating layer 102 provided on the metal substrate 101, and a metal layer 103 provided on the insulating layer 102. The insulating layer 102 can be composed of one selected from the group consisting of a resin layer made of the above-described thermosetting resin composition, a cured product of the thermosetting resin composition, and a laminate. Each of these resin layers and laminates may be composed of a B-stage thermosetting resin composition (resin sheet) before circuit processing of the metal layer 103, and may be a cured body obtained by curing it after circuit processing.

[0117] The metal layer 103 is provided on the insulating layer 102 and is circuit-processed. Examples of the metal constituting the metal layer 103 include one or more selected from copper, copper alloy, aluminum, aluminum alloy, nickel, iron, tin, etc. Among these, the metal layer 103 is preferably a copper layer or an aluminum layer, and particularly preferably a copper layer. By using copper or aluminum, the circuit processability of the metal layer 103 can be made good. The metal layer 103 may use a metal foil that can be obtained in a plate shape or a metal foil that can be obtained in a roll shape.

[0118] The lower limit of the thickness of the metal layer 103 is, for example, 0.01 mm or more, preferably 0.035 mm or more, and it can be applied to applications requiring high current. Also, the upper limit of the thickness of the metal layer 103 is, for example, 10.0 mm or less, preferably 5 mm or less. If it is below such a numerical value, the circuit processability can be improved, and the thinning of the entire substrate can be achieved.

[0119] The metal substrate 101 has a role of dissipating the heat accumulated in the metal base substrate 100. The metal substrate 101 is not particularly limited as long as it is a heat-dissipating metal substrate. For example, it can be a copper substrate, a copper alloy substrate, an aluminum substrate, or an aluminum alloy substrate. A copper substrate or an aluminum substrate is preferable, and a copper substrate is more preferable. By using a copper substrate or an aluminum substrate, the heat dissipation of the metal substrate 101 can be made good. The thickness of the metal substrate 101 can be appropriately set as long as the object of the present invention is not impaired.

[0120] The upper limit of the thickness of the metal substrate 101 is, for example, 20.0 mm or less, preferably 5.0 mm or less. The processability in the external shape processing, cutting processing, etc. of the metal base substrate 100 below this numerical value can be improved.

[0121] Also, the lower limit of the thickness of the metal substrate 101 is, for example, 0.01 mm or more, preferably 0.6 mm or more. By using the metal substrate 101 with this numerical value or more, the heat dissipation of the entire metal base substrate 100 can be improved.

[0122] In this embodiment, the metal base substrate 100 can be used for various substrate applications. However, since it has excellent thermal conductivity and heat resistance, it can be used as a printed circuit board using LEDs or power modules.

[0123] The metal base substrate 100 can have a metal layer 103 that is circuit-processed by etching or the like on a pattern. In this metal base substrate 100, a solder resist (not shown) may be formed on the outermost layer, and connection electrode portions may be exposed by exposure and development so that electronic components can be mounted.

[0124] [Semiconductor device] The metal base substrate (heat dissipation and insulation member) 100 of the embodiment can be used for various applications that require heat dissipation and insulation properties, and can be used, for example, in electronic devices such as semiconductor devices. FIG. 2 is a schematic cross-sectional view showing an example of a semiconductor device using the metal base substrate 100. A semiconductor element 201 is mounted on the metal layer 103 of the metal base substrate 100 via an adhesive layer 202 (die attach material). The semiconductor element 201 is connected to a connection electrode portion formed on the metal base substrate 100 via a bonding wire 203 and is mounted on the metal base substrate 100. Then, the semiconductor element 201 is collectively encapsulated by a sealing resin layer 205 on the metal base substrate 100.

[0125] On the metal substrate 101 side of the metal base substrate 100, a heat sink 207 is provided via a heat conduction layer 206 (thermal interface material (TIM)). The heat sink 207 is made of a material with excellent heat conductivity, and examples include metals such as aluminum, iron, and copper.

[0126] As described above, the embodiments of the present invention have been described, but these are examples of the present invention, and various configurations other than the above can also be adopted. An example of an embodiment will be appended below. 1. (A) An epoxy resin, (B) A thermosetting resin (excluding the epoxy resin (A)), (C) A phenoxy resin, (D) A thermally conductive filler, and a thermosetting resin composition comprising: The phenoxy resin (C) is A phenoxy resin obtained by reacting a bifunctional epoxy compound (c1) having two epoxy groups and A polyfunctional phenol compound (c2) having at least two phenolic hydroxyl groups. The bifunctional epoxy compound (c1) includes a compound represented by the formula (d-EP).

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Example

[0127] Hereinafter, the present invention will be described by way of examples and comparative examples, but the present invention is not limited thereto.

[0128] <Examples 1 to 3, Comparative Example 1 (Production of thermosetting resin composition (varnish-like))> According to the blending ratios shown in Table 1, each component and the solvent were stirred to obtain a varnish-like thermosetting resin composition. In Table 1, the content of the thermally conductive particles is the volume % with respect to the resin component of the thermosetting resin composition not containing the thermally conductive filler. Details of each component in Table 1 are as follows. The unit of the amount of each component in Table 1 is parts by mass.

[0129] (Epoxy resin) ·Epoxy resin 1: Epoxy resin having the following structure (manufactured by DIC Corporation, HP-4032D, liquid at room temperature) [Chemistry]

[0130] · Epoxy resin 2: Dicyclopentadiene type epoxy resin (manufactured by DIC, EPICLON HP-7200L, solid at room temperature) · Epoxy resin 3: Biphenyl type epoxy resin (manufactured by Mitsubishi Chemical Corporation, YX-4000K, solid at room temperature)

[0131] (Cyanate resin) · Cyanate resin 1: Manufactured by Lonza, Primaset "PT-30S"

[0132] (Phenolic resin) · Phenolic resin 1: Allyl group-containing phenol novolak resin (manufactured by Meiwa Kasei Co., Ltd., product name "MEH-8000H")

[0133] (Phenoxy resin) · Phenoxy resin 1: Phenoxy resin obtained by the following procedure. 62 parts by weight of epoxy compound 1, 31 parts by weight of phenol compound 1, 0.05 part by weight of triphenylphosphine (TPP), and 7 parts by weight of solvent (cyclohexanone) were charged into a reactor and melt-mixed at 100°C to 110°C for 1 hour. Then, the temperature of the mixture was raised to 180°C, and the reaction was carried out while removing the solvent under reduced pressure at this temperature. It was confirmed that the target molecular weight was obtained by GPC, the reaction was stopped, and a phenoxy resin represented by the following formula (1-1) was obtained. The reaction was carried out for 6 hours. After the reaction, 100 parts by weight of dimethylformamide was added to the resin to dissolve the resin, and it was cooled to room temperature. After cooling, it was purified by reprecipitation using methanol to obtain 100 parts by weight of a phenoxy resin represented by the following formula (1-1) (the average value of the number of repeating units n in formula (1-1) is 11, X is a structural unit derived from epoxy compound 1 of formula (3), Y is a structural unit derived from daidzein which is phenol compound 1, the weight average molecular weight Mw by GPC is 4236, and the dispersity (weight average molecular weight Mw) / (number average molecular weight Mn) is 4.28).

[0134] [Chemical formula]

[0135] · Phenoxy resin 2: The phenoxy resin obtained by the following procedure. 62 parts by weight of epoxy compound 2, 31 parts by weight of phenol compound 1, 0.05 parts by weight of triphenylphosphine (TPP), and 7 parts by weight of a solvent (cyclohexanone) were charged into a reactor and melt-mixed at 100 °C to 110 °C for 1 hour. Then, the temperature of the mixed solution was raised to 180 °C, and the reaction was carried out while removing the solvent under reduced pressure at this temperature. It was confirmed that the target molecular weight was achieved by GPC, and the reaction was stopped to obtain a phenoxy resin represented by the following formula (1-2). The reaction was carried out for 6 hours. After the reaction, 100 parts by weight of dimethylformamide was added to the resin to dissolve the resin, and it was cooled to room temperature. After cooling, it was purified by a reprecipitation method using methanol to obtain 100 parts by weight of a phenoxy resin represented by the following formula (1-2) (the average value of the number of repeating units n in formula (1-2) is 11, X is a structural unit derived from the epoxy compound of formula (3) and a structural unit derived from the epoxy compound of formula (4), Y is a structural unit derived from daidzein which is phenol compound 1, the weight-average molecular weight Mw by GPC is 5422, and the dispersity (weight-average molecular weight Mw) / (number-average molecular weight Mn) is 4.49).

[0136] [Chemical formula]

[0137] Note that the raw material compounds used in the synthesis of the above phenoxy resin 1 and phenoxy 2 are as follows. (Epoxy compound (c1)) · Epoxy compound 1: A tetramethylbiphenyl type epoxy resin represented by the following formula (3) (“YX4000” manufactured by Mitsubishi Chemical Corporation) [Chemical formula]

[0138] · Epoxy compound 2: A 1:1 mixture of a tetramethylbiphenyl type epoxy resin represented by the following formula (3) and a biphenyl type epoxy resin represented by the following formula (4) ("YL-6121" manufactured by Mitsubishi Chemical Corporation)

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[0139] (Phenol compound (c2)) · Phenol compound 1: Daidzein (a bifunctional phenol compound represented by the following formula (5))

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[0140] · Phenol compound 2: Naringenin (a trifunctional phenol compound represented by the following formula (6))

Chem.

[0141] · Phenoxy resin 3: A bisphenol A type phenoxy resin represented by the following formula (7) (without mesogenic structure, manufactured by Mitsubishi Chemical Corporation, YP-55)

[0142]

Chem.

[0143] (Thermally conductive particles) · Thermally conductive particle 1: Agglomerated boron nitride (manufactured by Mizushima Alloys & Iron Co., Ltd., HP40)

[0144] <Measurement of physical properties of resin molded body of thermosetting resin composition> For the cured product (resin molded body) of the thermosetting resin composition, the following physical properties were measured. The results are shown in Table 1.

[0145] (Thermal conductivity) · Fabrication of resin molded body Using the obtained thermosetting resin composition containing the heat conductive filler, it was sandwiched and set with a 0.018 mm copper foil, and compression molding was carried out at 10 MPa, 180 °C for 90 min to obtain a resin molded body (sample 1 for measuring thermal conductivity). A sample for measuring the thermal diffusivity with a diameter of 10 mm was cut out from the obtained molded body and used for measuring the thermal diffusivity.

[0146] · Density (specific gravity) of resin molded body The density (specific gravity) was measured in accordance with JIS K 6911 (General test methods for thermosetting plastics). As the test piece, one cut out from the above resin molded body with a length of 2 cm and a width of 2 cm was used. The unit of density (specific gravity) (ρ) is g / cm 3 shall be.

[0147] · Specific heat of resin molded body For the obtained resin molded body, the specific heat (Cp) was measured by the DSC method.

[0148] · Measurement of thermal conductivity of resin molded body From the obtained resin molded body, a piece cut out to a diameter of 10 mm for thickness direction measurement was used as the test piece. Next, the thermal diffusivity (α) in the thickness direction of the plate-shaped test piece was measured by the transient method using a Xe flash analyzer TD-1RTV manufactured by ULVAC. The measurement was carried out under the conditions of an air atmosphere and 25 °C. For the resin molded body, the thermal conductivity was calculated based on the following formula from the measured values of the obtained thermal diffusivity (α), specific heat (Cp), and density (ρ). The results are shown in Table 1. Thermal conductivity [W / m·K] = α [m 2 / s] × Cp [J / kg·K] × ρ [g / cm 3 In Table 1, the thermal conductivity of the resin molded body was taken as "thermal conductivity".

[0149] (Moisture absorption rate) The copper foil was removed from the obtained resin molded body by etching, and the moisture absorption rate (%) was calculated from the weight change before and after leaving it for 48 hours under the conditions of 30 °C / 90% RH. ​

[0150] (Solder heat resistance) After cutting the obtained resin molded body into 50 mm × 50 mm with a grinder saw, a sample was prepared by leaving half of the copper foil by etching, and evaluated according to JIS C 6481. The evaluation was performed by examining the presence or absence of appearance abnormalities after immersing in a solder bath at 300 °C for 5 minutes. The evaluation criteria are as follows. <Evaluation criteria> ○: No abnormality ×: Abnormality (there are bulging parts overall)

[0151] (Moisture absorption solder heat resistance) After cutting the obtained resin molded body into 50 mm × 50 mm with a grinder saw, a sample was prepared by performing half-etching according to JIS C 6481. After standing in an environment of a temperature of 40 °C and a humidity of 90% for 2 days, it was floated in a solder bath at 297 °C with the copper foil surface facing down, and the presence or absence of appearance abnormalities after 1 minute was examined. The evaluation criteria are as follows. The results are shown in Table 1. <Evaluation criteria> ○: No abnormality ×: Bulging (there are bulging parts overall)

[0152]

Table 1

Explanation of symbols

[0153] 100 Metal base substrate 101 Metal substrate 102 Insulating layer 103 Metal layer 200 Semiconductor device 201 Semiconductor element 202 Adhesive layer 203 Bonding wire 205 Encapsulating resin layer 206 Heat conduction layer 207 Heat sink

Claims

1. (A) an epoxy resin, (B) a thermosetting resin (excluding the epoxy resin (A)), (C) a phenoxy resin, (D) a thermally conductive filler, and is a thermosetting resin composition containing, the phenoxy resin (C) is, a bifunctional epoxy compound (c1) having two epoxy groups, a polyfunctional phenol compound (c2) having at least two phenolic hydroxyl groups, and is a phenoxy resin obtained by reacting, the bifunctional epoxy compound (c1) contains a compound represented by the formula (d-EP), 【Chemical 1】 X in the formula (d-EP) is a divalent group having a mesogenic skeleton, the polyfunctional phenol compound (c2) is at least one selected from the compounds represented by the formulas (p1) to (p8), 【Chemical Formula 2】 【Chemical Formula 3】 In the above formulas (p1) to (p8), R １１ and R １２ each independently represents a hydrogen atom, an alkoxy group having 1 to 4 carbon atoms, or a linear or branched alkyl group having 1 to 4 carbon atoms. a thermosetting resin composition.

2. In the polyfunctional phenol compound (c2) represented by the formulas (p1) to (p8), R １１ and R １２ The thermosetting resin composition according to claim 1, wherein all of are hydrogen atoms.

3. The thermosetting resin composition according to claim 1 or 2, wherein X in the formula (d-EP) contains a divalent group represented by the formula (2): [Chemical Formula 4] In formula (2), R １ ~R ８ each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and * represents the linking position.

4. In the group represented by the formula (2), R １ , R ４ , R ５ , and R ８ are alkyl groups having 1 to 4 carbon atoms, and R ２ , R ３ , R ６ , and R ７ are hydrogen atoms. The thermosetting resin composition according to claim 3.

5. In the group represented by the formula (2), R １ , R ４ , R ５ , and R ８ are methyl groups, and R ２ , R ３ , R ６ , and R ７ are hydrogen atoms. The thermosetting resin composition according to claim 3.

6. In the group represented by the formula (2), R １ ~R ８ The thermosetting resin composition according to claim 3, wherein all of are hydrogen atoms.

7. At least one of X in the formula (d-EP) is R １ , R ４ , R ５ , and R ８ is a methyl group, and R ２ , R ３ , R ６ , and R ７ is a divalent group represented by the formula (2) and is a hydrogen atom, and At least one of X in the formula (d-EP) is R １ ~R ８ The thermosetting resin composition according to claim 3, which is a divalent group represented by the formula (2) in which all of

8. the polyfunctional phenol compound (c2) is at least one selected from the compounds represented by the formulas (p1) to (p4), the phenoxy resin has a structure represented by the formula (1), and the thermosetting resin composition according to any one of claims 1 to 7: [Chemical Formula 5] In the formula (1), n is a number representing a repeating unit and represents an integer of 2 to 50, X has the same meaning as X in the formula (d-EP), Y is independently at least one divalent group selected from the following formulas (y1) to (y4), 【Chemical Formula 6】 【Chemical Formula 7】 In formulas (y1) to (y4), R １１ and R １２ each independently represents a hydrogen atom, an alkoxy group having 1 to 4 carbon atoms, or a linear or branched alkyl group having 1 to 4 carbon atoms, and * represents a linking position.

9. The thermosetting resin composition according to any one of claims 1 to 8, wherein the weight average molecular weight of the phenoxy resin (C) is 1,000 or more and 10,000 or less.

10. The thermosetting resin composition according to any one of claims 1 to 9, further containing an organic solvent (E).

11. The thermosetting resin composition according to any one of claims 1 to 10, wherein the epoxy resin (A) contains an epoxy resin that is liquid at room temperature.

12. The thermosetting resin composition according to claim 11, wherein the epoxy resin (A) further contains an epoxy resin that is solid at room temperature.

13. The thermosetting resin composition according to any one of claims 1 to 12, wherein the content of the thermally conductive filler (D) is 60% by mass or more and 98% by mass or less based on the total solid content of the thermosetting resin composition.

14. The thermosetting resin composition according to any one of claims 1 to 13, wherein the thermally conductive filler (D) contains at least one selected from silica, alumina, aluminum nitride, boron nitride, silicon nitride, silicon carbide, and magnesium oxide.

15. The thermosetting resin composition according to any one of claims 1 to 14, wherein the thermally conductive filler (D) contains boron nitride.

16. The thermosetting resin composition according to claim 14 or 15, wherein the boron nitride is monodisperse particles, granular particles, aggregated particles, or a mixture thereof of flaky boron nitride.

17. The thermosetting resin composition according to any one of claims 1 to 16, wherein the thermosetting resin (B) contains at least one selected from cyanate resins, maleimide resins, phenol resins, and benzoxazine resins.

18. The thermosetting resin composition according to any one of claims 1 to 17, wherein the thermosetting resin (B) contains a cyanate resin.

19. The thermosetting resin composition according to any one of claims 1 to 18, further comprising a curing accelerator.

20. A resin sheet comprising the thermosetting resin composition according to any one of claims 1 to 19.

21. The resin sheet according to claim 20, which is in a B-stage state.

22. A heat generating member, A heat radiating member, An electronic device comprising a thermally conductive sheet provided between the heat generating member and the heat radiating member, wherein The thermally conductive sheet is made of a cured product of the resin sheet according to claim 20 or 21.

23. The electronic device according to claim 22, wherein the thermal conductivity of the thermally conductive sheet is 12 W / m·K or more.

24. A metal base substrate comprising a metal substrate, A thermally conductive sheet, And a metal layer in this order, wherein The thermally conductive sheet is made of a cured product of the resin sheet according to claim 20 or 21.

25. The metal base substrate according to claim 24, wherein the thermal conductivity of the thermally conductive sheet is 12 W / m·K or more.

26. An electronic device comprising the metal base substrate according to claim 24 or 25.

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