Phenoxy resin, thermosetting resin composition, thermally conductive sheet, resin substrate, laminate, and electronic apparatus

Abstract

To provide a phenoxy resin, a cured product of which has high thermal conductivity.SOLUTION: A phenoxy resin is a product from the reaction between (A) a bifunctional epoxy compound having two epoxy groups, (B) a polyfunctional epoxy compound having three or more epoxy groups and (C) a polyfunctional phenolic compound having at least two phenolic hydroxy groups.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a phenoxy resin, a thermosetting resin composition containing the same, and a resin sheet, a resin substrate, and a circuit board produced from the thermosetting resin composition. More specifically, the present invention relates to a phenoxy resin that can be used as a highly thermally conductive material and uses thereof. [Background technology]

[0002] With the increasing integration of semiconductors and the rapid improvement in the processing power of electronic devices, electronic components with high processing power generate a lot of heat. Therefore, heat countermeasures to effectively dissipate heat from electronic components to the outside have become an extremely important issue. As a heat dissipation measure, thermally conductive members made of heat dissipating materials such as metals, ceramics, and polymer compositions are used in heat dissipation components such as printed wiring boards, semiconductor packages, housings, heat pipes, heat sinks, and heat diffusion plates.

[0003] Among these heat dissipation members, thermally conductive epoxy resin molded articles molded from epoxy resin compositions are excellent in electrical insulation properties, mechanical properties, heat resistance, chemical resistance, adhesive properties, etc., and are therefore widely used mainly in the electrical and electronic fields as castings, laminates, sealing materials, thermally conductive sheets, adhesives, etc.

[0004] Epoxy resin compositions that form thermally conductive epoxy resin moldings are known to contain a thermally conductive filler with high thermal conductivity blended into a polymer matrix material such as resin or rubber. Thermally conductive fillers include metal oxides such as aluminum oxide, magnesium oxide, zinc oxide, and quartz, metal nitrides such as boron nitride and aluminum nitride, metal carbides such as silicon carbide, metal hydroxides such as aluminum hydroxide, metals such as gold, silver, and copper, carbon fiber, and graphite.

[0005] When even higher thermal conductivity is required, thermally conductive epoxy resin compositions and thermally conductive epoxy resin molded articles in which special thermally conductive fillers are blended into epoxy resins have been proposed (for example, Patent Document 1). 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. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-193504 [Patent Document 2] Patent Application No. 2004-331811 Summary of the Invention [Problem to be solved by the invention]

[0007] However, as a result of investigations by the present inventors, it has been found that the resin composition described in Patent Document 2 has room for further improvement in terms of thermal conductivity. [Means for solving the problem]

[0008] The present invention has been made in view of the above problems, and has been accomplished based on the discovery that a novel phenoxy resin having a specific structure has high thermal conductivity.

[0009] According to the present invention, a bifunctional epoxy compound (A) having two epoxy groups; a multifunctional epoxy compound (B) having three or more epoxy groups; a polyfunctional phenol compound (C) having at least two phenolic hydroxyl groups, The bifunctional epoxy compound (A) includes a compound represented by formula (d-EP), [ka] X in the formula (d-EP) is a divalent organic group having a mesogenic skeleton represented by formula (2), [ka] In equation (2), R 1 ~R 8 are independently a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, * represents the linking position, The polyfunctional phenol compound (C) includes at least one selected from the compounds represented by formulas (p1) to (p17), [ka] [ka] [ka] [ka] [ka] [ka]

[0010] In the formulae (p1) to (p17), R independently represents a hydrogen atom, an alkoxy group having 1 to 4 carbon atoms, or a linear or branched alkyl group having 1 to 6 carbon atoms.

[0011] The present invention also provides a thermosetting resin composition containing the above-mentioned phenoxy resin.

[0012] According to the present invention, there is also provided a thermally conductive sheet formed from the above thermosetting resin composition.

[0013] The present invention also provides a resin substrate comprising the cured product of the thermally conductive sheet.

[0014] According to the present invention, there is also provided an electronic device comprising the above resin substrate.

[0015] Furthermore, according to the present invention, a metal layer; a resin layer laminated on at least one surface of the metal layer, There is provided a laminate in which the resin layer is made of a cured product of the thermally conductive sheet. [Effects of the Invention]

[0016] According to the present invention, there are provided a phenoxy resin having high thermal conductivity and a resin composition using the same. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view schematically illustrating a structure of a metal base substrate according to an embodiment of the present invention.

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are designated by similar reference numerals, and their description will be omitted as appropriate. In this specification, the notation "to" means "from above to below" unless otherwise specified.

[0019] [Phenoxy resin] The phenoxy resin of this embodiment is a resin obtained by reacting a bifunctional epoxy compound (A) having two epoxy groups, a multifunctional epoxy compound (B) having three or more epoxy groups, and a multifunctional phenolic compound (C) having at least two phenolic hydroxyl groups. More specifically, the phenoxy resin of this embodiment is a polymer obtained by reacting the epoxy groups of the bifunctional epoxy compound (A) and the epoxy groups of the multifunctional epoxy compound (B) with the phenolic hydroxyl groups of the multifunctional phenolic compound (C) to form a crosslinked structure. That is, the phenoxy resin of this embodiment is a phenoxy resin containing structural units derived from the bifunctional epoxy compound (A) having two epoxy groups, structural units derived from the multifunctional epoxy compound (B) having three or more epoxy groups, and structural units derived from the multifunctional phenolic compound (C) having at least two phenolic hydroxyl groups.

[0020] In the phenoxy resin of the present embodiment, the difunctional epoxy compound (A) includes a compound represented by the formula (d-EP).

[0021] [ka] X in formula (d-EP) is a divalent organic group having a mesogenic skeleton represented by formula (2),

[0022] [ka]

[0023] In equation (2), R 1 ~R 8 are independently a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and * represents the linking position.

[0024] The phenoxy resin of the present embodiment contains a structural unit derived from a bifunctional epoxy compound (A) in which X in formula (d-EP) is a mesogenic skeleton represented by formula (2), and thus the cured product thereof has high thermal conductivity.

[0025] The phenoxy resin of this embodiment has a structure represented by the following formula (1), which is obtained by the polymerization reaction between a bifunctional epoxy compound (A) and a bifunctional polyfunctional phenolic compound (C), and also has a three-dimensional network structure obtained by the polymerization reaction between a polyfunctional epoxy compound (B) having three or more epoxy groups and the polyfunctional phenolic compound (C). This allows the phenoxy resin of this embodiment to have high thermal conductivity and high heat resistance. Each monomer component constituting the phenoxy resin of this embodiment will be described below.

[0026] [ka]

[0027] In formula (1), X represents a group derived from the difunctional epoxy compound (A), and Y represents a group derived from the polyfunctional phenol compound (C) when it is difunctional.

[0028] In this embodiment, the difunctional epoxy compound (A) includes a compound represented by the formula (d-EP).

[0029] [ka]

[0030] X in formula (d-EP) is a divalent organic group having a mesogenic skeleton represented by formula (2).

[0031] [ka]

[0032] In equation (2), R 1 ~R 8 are independently a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and * represents the linking position.

[0033] In one embodiment, the group represented by formula (2) which is X in formula (d-EP) is preferably a group in which R1, R4, R5, and R8 are alkyl groups having 1 to 6 carbon atoms, and R2, R3, R6, and R7 are hydrogen atoms. Among these, a group in formula (2) 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 "tetramethylbiphenyl group") is preferred because it allows the resulting phenoxy resin to have an excellent balance between thermal conductivity and heat resistance.

[0034] In one embodiment, the group represented by formula (2) which is X in formula (d-EP) may be a group in which R1, R4, R5, and R8 are alkyl groups each having one carbon atom, and R2, R3, R6, and R7 are hydrogen atoms (referred to as a "biphenyl group"). By containing such a group, the phenoxy resin has excellent thermal conductivity and heat resistance.

[0035] In one embodiment, X in formula (d-EP) preferably contains a tetramethylbiphenyl group and a biphenyl group. A phenoxy resin containing these groups in combination can have an excellent balance of thermal conductivity and heat resistance.

[0036] In one embodiment, the polyfunctional epoxy compound (B) having three or more epoxy groups includes at least one selected from a trisphenolmethane type epoxy resin, a naphthalene type epoxy compound, and a triazine type epoxy compound.

[0037] In one embodiment, the polyfunctional epoxy compound (B) has an epoxy equivalent of 50 to 300 g / eq, preferably 100 to 250 g / eq.

[0038] In one embodiment, the polyfunctional epoxy compound (B) is a trisphenolmethane-type epoxy resin represented by formula (m1), a naphthalene-type epoxy compound represented by formula (m2) or formula (m3), or a triazine-type epoxy compound represented by formula (m4).

[0039] [ka] [ka]

[0040] In formula (m1), n1 is an integer of 0 to 4, preferably 0 or 1, and more preferably 1. In formulas (m1) to (m3), R 11 ~R 13 are independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. 11 ~R 13 are all hydrogen atoms.

[0041] In this embodiment, the polyfunctional phenol compound (C) 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 includes at least one selected from the compounds represented by formulas (p1) to (p17).

[0042] [ka] [ka] [ka] [ka] [ka] [ka]

[0043] In formulas (p1) to (p17), R independently represents a hydrogen atom, an alkoxy group having 1 to 4 carbon atoms, or a linear or branched alkyl group having 1 to 6 carbon atoms, and is preferably a hydrogen atom or a methoxy group. The phenoxy resin of this embodiment contains structural units derived from the compounds represented by formulas (p1) to (p17), and thus the cured product thereof has high thermal conductivity. In this embodiment, the polyfunctional phenol compounds having a flavanone skeleton represented by formulae (P12), (p13), (p16), and (p17) include stereoisomers. Specifically, the isoflavanone compounds of formulae (p12) and (p16) include stereoisomers in which the C2 carbon is an asymmetric carbon atom, and the isoflavanone compounds of formulae (p13) and (p17) include stereoisomers in which the C3 atom is an asymmetric carbon atom.

[0044] In one embodiment, the phenoxy resin of this embodiment may contain structural units derived from another component (D) in addition to the bifunctional epoxy compound (A), polyfunctional epoxy compound (B), and polyfunctional phenol compound (C) described above, as long as the properties of the phenoxy resin are not affected. Examples of component (D) include naphthalene-type epoxy compounds, 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 of these. When the phenoxy resin of this embodiment contains structural units derived from component (D), the content of these structural units is, for example, 10 mol % or less, preferably 5 mol % or less, based on the total structural units constituting the phenoxy resin.

[0045] An example of the naphthalene type epoxy compound is a bifunctional epoxy compound represented by formula (EP1).

[0046] [ka]

[0047] Formula (EP1)R 14 are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

[0048] In one embodiment, the phenoxy resin of the present invention comprises 4,4′-diglycidylbiphenyl and / or 4,4′-diglycidyl-3,3′,5,5′-tetramethylbiphenyl as the difunctional epoxy compound (A) and a pentafunctional trisphenolmethane epoxy compound represented by formula (m1) (n1=1, R 11 =H) with difunctional 2,7-dihydroxynaphthalene and / or 2,6-dihydroxynaphthalene as the polyfunctional phenol compound (C).

[0049] In one embodiment, the phenoxy resin of the present invention comprises 4,4'-diglycidylbiphenyl and / or 4,4'-diglycidyl-3,3',5,5'-tetramethylbiphenyl as the difunctional epoxy compound (A) and a tetrafunctional naphthalene-type epoxy compound (R 12 =H, R 13 =H) and a bifunctional epoxy compound (R 14 =H) with difunctional 2,7-dihydroxynaphthalene and / or 2,6-dihydroxynaphthalene as the polyfunctional phenol compound (C).

[0050] In one embodiment, the phenoxy resin of the present invention is a resin obtained by reacting 4,4'-diglycidylbiphenyl and / or 4,4'-diglycidyl-3,3',5,5'-tetramethylbiphenyl as the difunctional epoxy compound (A), a trifunctional triazine epoxy compound represented by formula (m4) as the polyfunctional epoxy compound (B), and a difunctional 2,7-dihydroxynaphthalene and / or 2,6-dihydroxynaphthalene as the polyfunctional phenol compound (C).

[0051] The weight-average molecular weight (Mw) of the phenoxy resin of this 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 a value measured by gel permeation chromatography and converted using a standard polystyrene calibration curve. By setting Mw within the above range, the thermal conductivity of the phenoxy resin can be further improved.

[0052] In this embodiment, the weight-average molecular weight (Mw) of the phenoxy resin can be measured by obtaining a molecular weight distribution curve using Gel Permeation Chromatography (GPC). The weight-average molecular weight (Mw), number-average molecular weight (Mn), and polydispersity index (PDI: Mw / Mn) of the phenoxy resin are calculated using polystyrene-equivalent values ​​obtained from a calibration curve of standard polystyrene (PS) obtained by GPC measurement.

[0053] The measurement conditions for GPC are, for example, as follows. Tosoh Corporation gel permeation chromatography device HLC-8320GPC Column: TSK-GEL GMH, G2000H, SuperHM-M manufactured by Tosoh Corporation Detector: RI detector for liquid chromatography Measurement temperature: 40℃ Solvent: THF Sample concentration: 2.0 mg / ml

[0054] The polydispersity (Mw / Mn) of the phenoxy resin is, for example, 1.00 to 5.00, preferably 1.20 to 4.00, and more preferably 1.30 to 3.50. By setting the polydispersity within the above range, the thermal conductivity and fluidity of the phenoxy resin can be further improved.

[0055] The phenoxy resin may contain a low-molecular-weight phenoxy resin having a weight-average molecular weight (Mw) of 1,000 or less. When the phenoxy resin contains a low-molecular-weight phenoxy resin, the low-molecular-weight phenoxy resin accounts for, for example, 5% to 60% and preferably 5% to 50% of the total area of ​​components corresponding to a weight-average molecular weight Mw of 1,000 or less, relative to the total area (100%) of the entire molecular weight distribution obtained by GPC measurement. Phenoxy resins containing a low-molecular-weight phenoxy resin in an amount within the above range have improved fluidity and excellent handleability. Therefore, for example, processing stability is improved when the phenoxy resin is processed into a sheet or film form.

[0056] From the viewpoint of the effects of the present invention, the epoxy equivalent of the phenoxy resin 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.

[0057] The phenoxy resin of this embodiment, having the above-described structure, can improve the thermal conductivity of the cured product thereof. The thermal conductivity of the cured product of the phenoxy resin of this embodiment 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.

[0058] The phenoxy resin of this embodiment has a crosslinked structure, and thus its cured product has a high 1% weight loss temperature. The 1% weight loss temperature of the cured product of the phenoxy resin of this embodiment is 300°C or higher, preferably 310°C or higher, more preferably 320°C or higher, and even more preferably 330°C or higher. The upper limit of the 1% weight loss temperature of the cured product of the phenoxy resin of this embodiment is, for example, 400°C or lower.

[0059] [Production of phenoxy resin] The phenoxy resin of this embodiment can be synthesized by reacting a bifunctional epoxy compound (A) represented by formula (d-EP), a multifunctional epoxy compound (B) having three or more epoxy groups, and a multifunctional phenol compound (C) having at least two phenolic hydroxyl groups. The phenoxy resin of this embodiment may be synthesized using the above-mentioned component (C) in addition to the bifunctional epoxy compound (A), multifunctional epoxy compound (B), and multifunctional phenol compound (C), as long as the effects of the present invention are not impaired.

[0060] [ka]

[0061] X in formula (d-EP) is as defined above. The difunctional epoxy compound (A), the polyfunctional epoxy compound (B) having three or more epoxy groups, and the polyfunctional phenol compound (C) having at least two phenolic hydroxyl groups are the same as those described above for the phenoxy resin of this embodiment.

[0062] The above reaction can be carried out in the absence of a solvent or in the presence of a reaction solvent using a reaction catalyst.

[0063] Suitable reaction solvents include 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. Use of a reaction solvent can reduce the initial viscosity and improve the reactivity of the monomer.

[0064] As the reaction catalyst, a conventionally known polymerization catalyst can be used, and alkali metal hydroxides, tertiary amine compounds, quaternary ammonium compounds, tertiary phosphine compounds, quaternary phosphonium compounds, and imidazole compounds are preferably used.

[0065] Specifically, a polyfunctional epoxy compound (a), a polyfunctional phenol compound (b), a reaction catalyst, and, if necessary, a reaction solvent are added and melt-mixed under 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 normal pressure. After melt-mixing, the mixed solution is heated and a polymerization reaction is carried out at a predetermined reaction temperature under reduced pressure or normal pressure. The reaction temperature is about 140 to 180°C, the reaction time is about 2 to 20 hours, and the reaction pressure is about 1 to 760 Torr.

[0066] After the reaction is complete, the phenoxy resin can be obtained as a resin dissolved in a suitable solvent by performing solvent substitution, etc. The phenoxy resin obtained by the solvent reaction can also be obtained as a solvent-free solid resin by removing the solvent using an evaporator, etc.

[0067] In the above synthesis method, the degree of polymerization can be adjusted by appropriately selecting reaction conditions such as the amounts of starting materials used, reaction temperature, and reaction time, thereby obtaining a phenoxy resin having a desired weight average molecular weight.

[0068] [Thermosetting resin composition] In one embodiment, the thermosetting resin composition contains the above-mentioned phenoxy resin and may contain other components depending on the intended use. Components that may constitute the thermosetting resin composition of this embodiment will be described below.

[0069] (phenoxy resin) The thermosetting resin composition of this embodiment contains the above-mentioned phenoxy resin. When the thermosetting resin composition of this embodiment is used, for example, as a thermal insulating material, the content of the phenoxy resin is, for example, 1 to 70 mass %, preferably 2 to 50 mass %, and more preferably 3 to 45 mass %, based on the total solid content (non-volatile content) of the thermosetting resin composition excluding the inorganic filler described below.

[0070] (thermal conductive filler) The thermosetting resin composition of this embodiment may contain a thermally conductive filler. By incorporating a thermally conductive filler, the thermosetting resin composition of this embodiment can be used as a material for producing a heat dissipation member. The thermally conductive filler may contain, for example, highly thermally conductive inorganic particles having a thermal conductivity of 20 W / m·K or more. Examples of highly thermally conductive inorganic particles include alumina, aluminum nitride, boron nitride, silicon nitride, silicon carbide, and magnesium oxide. These may be used alone or in combination of two or more.

[0071] When boron nitride is used as the thermally conductive filler, the boron nitride may contain monodisperse particles, agglomerated particles, or a mixture thereof of scaly boron nitride. The scaly boron nitride may be granulated. The use of agglomerated particles of scaly boron nitride can further enhance the thermal conductivity of the resulting thermosetting resin composition. The agglomerated particles may be sintered or non-sintered.

[0072] (thermosetting resin) The thermosetting resin composition of this embodiment may contain a thermosetting resin other than the above-mentioned phenoxy resin, as long as the effects of the present invention are not impaired. Examples of the above-mentioned other thermosetting resins include epoxy resins other than the above-mentioned phenoxy resins, polyimide resins, benzoxazine resins, unsaturated polyester resins, phenolic resins, melamine resins, silicone resins, cyanate resins, bismaleimide resins, acrylic resins, phenol derivatives, and derivatives thereof. These thermosetting resins can be any monomer, oligomer, or polymer having two or more reactive functional groups per molecule, and their molecular weights and molecular structures are not particularly limited. These may be used alone or in combination of two or more.

[0073] (hardening agent) The thermosetting resin composition of this embodiment may contain a curing agent as needed. The curing agent is selected depending on the type of thermosetting resin, and is not particularly limited as long as it reacts with the thermosetting resin. Examples of the curing agent include phenolic resin-based curing agents, amine-based curing agents, acid anhydride-based curing agents, and mercaptan-based curing agents. These may be used alone or in combination of two or more.

[0074] (curing accelerator) The thermosetting resin composition may contain a curing accelerator as needed. The type and amount of the curing accelerator are not particularly limited, but an appropriate one can be selected from the viewpoints of reaction rate, reaction temperature, storage properties, and the like.

[0075] Examples of the curing accelerator include imidazoles, organic phosphorus compounds, tertiary amines, phenolic compounds, and organic acids. These may be used alone or in combination of two or more. Among these, it is preferable to use nitrogen atom-containing compounds such as imidazoles from the viewpoint of improving heat resistance.

[0076] (Silane coupling agent) The thermosetting resin composition may contain a silane coupling agent, which can improve the compatibility of the thermally conductive filler in the thermosetting resin composition. The coupling agent may be added to the thermosetting resin composition, or may be used by treating the surface of the thermally conductive filler.

[0077] The thermosetting resin composition of the present embodiment may contain components other than the components described above. Examples of such components include an antioxidant and a leveling agent.

[0078] [Method for producing thermosetting resin composition] The thermosetting resin composition of this embodiment can be prepared as a resin varnish (a varnish-like thermosetting resin composition) by dissolving, mixing, and stirring the above-described components in a solvent. This mixing can be performed using various mixers, such as ultrasonic dispersion, high-pressure collision dispersion, high-speed rotation dispersion, bead mill, high-speed shear dispersion, and rotation-revolution dispersion. Alternatively, the thermosetting resin composition of this embodiment can be produced by uniformly mixing the above-described components in a mixer or blender, such as a tumbler mixer or Henschel mixer, and then kneading the mixture while heating using a kneader, roll, disperser, azimuth homomixer, planetary mixer, or the like. The kneading temperature must be within a range that does not cause a curing reaction; for example, melt-kneading at approximately 70 to 150°C is preferred. After kneading, the mixture may be cooled and solidified, and the kneaded mixture may be processed into powder, granules, tablets, or sheets.

[0079] The solvent is not particularly limited, but 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.

[0080] [Uses of thermosetting resin compositions] (resin sheet) The resin sheet of this embodiment includes a carrier substrate and a resin layer formed on the carrier substrate and made of the thermosetting resin composition of this embodiment. The resin sheet of this embodiment can be used as a thermally conductive resin sheet for producing a heat dissipation member. The thermally conductive sheet of this embodiment is provided, for example, between a heat generating element such as a semiconductor chip and a substrate such as a lead frame or wiring board (interposer) on which the heat generating element is mounted, or between the substrate and a heat dissipation member such as a heat sink.

[0081] The resin sheet can be obtained by, for example, applying a varnish-like thermosetting resin composition to a carrier substrate, and then subjecting the resulting coating film (resin layer) to a solvent removal treatment. The solvent content in the resin sheet can be 10% by weight or less based on the total weight of the thermosetting resin composition. For example, the solvent removal treatment can be performed at 80°C to 200°C for 1 minute to 30 minutes.

[0082] In this embodiment, the carrier substrate may be, for example, a polymer film or a metal foil. Examples of the polymer film include, but are not limited to, polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonates, release papers such as silicone sheets, and heat-resistant thermoplastic resin sheets such as fluorine-based resins and polyimide resins. Examples of the metal foil include, but are not limited to, 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, and tin and tin-based alloys.

[0083] (Resin substrate) The resin substrate of this embodiment includes an insulating layer made of the cured product of the thermosetting resin composition. This resin substrate can be used as a material for a printed circuit board on which electronic components such as LEDs and power modules are mounted.

[0084] (Laminated board) As an example of the use of the resin substrate of this embodiment, a laminated plate will be described with reference to FIG. FIG. 1 is a cross-sectional view showing an example of the configuration of a metal base substrate 100 provided with a cured resin sheet.

[0085] 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 made of one material selected from the group consisting of a resin layer made of the above-mentioned thermosetting resin composition, a cured product of the thermosetting resin composition, and a laminate. Each of these resin layers and laminates can be made of a thermosetting resin composition in a B-stage state before circuit processing of the metal layer 103, and can be a cured product obtained by curing the resin composition after circuit processing.

[0086] The metal layer 103 is provided on the insulating layer 102 and is subjected to circuit processing. Examples of metals constituting the metal layer 103 include one or more selected from copper, copper alloys, aluminum, aluminum alloys, nickel, iron, tin, and the like. Among these, the metal layer 103 is preferably a copper layer or an aluminum layer, and particularly preferably a copper layer. The use of copper or aluminum can improve the circuit processability of the metal layer 103. The metal layer 103 may be a metal foil available in a plate form or a metal foil available in a roll form.

[0087] The lower limit of the thickness of the metal layer 103 is, for example, 0.01 mm or more, and preferably 0.035 mm or more, so that the metal layer 103 can be used in applications requiring a high current. The upper limit of the thickness of the metal layer 103 is, for example, 10.0 mm or less, and preferably 5 mm or less. If the thickness is less than this value, circuit processability can be improved, and the entire substrate can be made thinner.

[0088] The metal substrate 101 has a role of dissipating 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, but may be, for example, a copper substrate, a copper alloy substrate, an aluminum substrate, or an aluminum alloy substrate, with a copper substrate or an aluminum substrate being preferred, and a copper substrate being more preferred. By using a copper substrate or an aluminum substrate, the heat dissipation properties of the metal substrate 101 can be improved.

[0089] The thickness of the metal substrate 101 can be set appropriately as long as it does not impair the object of the present invention. The upper limit of the thickness of the metal substrate 101 is, for example, 20.0 mm or less, and preferably 5.0 mm or less. By using a metal substrate 101 having a thickness of this value or less, the workability of the metal base substrate 100 in the outer shaping and cutting processes can be improved.

[0090] The lower limit of the thickness of the metal substrate 101 is, for example, 0.01 mm or more, and preferably 0.6 mm or more. By using a metal substrate 101 with a thickness equal to or greater than this value, the heat dissipation properties of the metal base substrate 100 as a whole can be improved.

[0091] In this embodiment, the metal base substrate 100 can be used for various substrate applications, but because it has excellent thermal conductivity and heat resistance, it can be used as a printed circuit board that uses an LED or power module.

[0092] The metal base substrate 100 may have a metal layer 103 that has been circuitized by etching or the like into a pattern. In this metal base substrate 100, a solder resist (not shown) may be formed on the outermost layer, and connection electrodes may be exposed so that electronic components can be mounted thereon by exposure and development.

[0093] (electronic equipment) The resin sheet, resin substrate, and laminate of the present embodiment described above are used as substrates for mounting electronic components thereon to manufacture electronic devices. Alternatively, the thermosetting resin composition of the present embodiment can be used as an encapsulant for encapsulating electronic components.

[0094] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted as long as they do not impair the effects of the present invention. [Example]

[0095] EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these.

[0096] The product names mentioned in the examples represent the following compounds. (Difunctional epoxy compound) YL-6121: A mixture of 50% by mass of a tetramethylbiphenyl-type epoxy compound represented by the following formula (3) and 50% by mass of a biphenyl-type epoxy compound represented by the following formula (4). Epoxy equivalent: 171. Manufactured by Mitsubishi Chemical Corporation. [ka] [ka]

[0097] (Multifunctional epoxy compound) YL-6677: A mixture of 25% by mass of a biphenyl-type epoxy compound represented by formula (4) and 75% by mass of a trisphenolmethane-type epoxy resin (n1 = 0 to 4) represented by formula (5). Epoxy equivalent: 163. Manufactured by Mitsubishi Chemical Corporation.

[0098] [ka] [ka]

[0099] HP4770: A mixture of 10% by mass of a tetrafunctional naphthalene-type epoxy compound represented by formula (11), 40% by mass of a trifunctional naphthalene-type epoxy compound represented by formula (12), and 50% by mass of a difunctional naphthalene-type epoxy compound represented by formula (13). Epoxy equivalent: 205. Manufactured by DIC Corporation. [ka]

[0100] TEPIC-S (triglycidyl isocyanurate): A trifunctional triazine-type epoxy compound represented by formula (14). Epoxy equivalent: 110. Manufactured by Nissan Chemical Industries, Ltd. [ka]

[0101] (Example 1-1) 64 parts by weight of epoxy compound (YL-6121:YL-6677 = 97.5:2.5 (epoxy equivalent ratio)), 30 parts by weight of 2,7-dihydroxynaphthalene, 0.05 parts by weight of triphenylphosphine (TPP), and 7 parts by weight of solvent (cyclohexanone) were added to a reactor and melt-mixed at 100-110°C for 1 hour. The mixture was then heated to 150°C and reacted at that temperature while removing the solvent under reduced pressure. Once the target molecular weight was confirmed by GPC, the reaction was terminated to obtain a phenoxy resin. The reaction was carried out for 15 hours. After the reaction, 100 parts by weight of dimethylformamide was added to the resin to dissolve the resin, and the resin was cooled to room temperature. After cooling, the mixture was purified by reprecipitation using methanol to obtain 100 parts by weight of a phenoxy resin.

[0102] (Example 1-2) A phenoxy resin was obtained in the same manner as in Example 1-1, except that the mixing ratio of the epoxy compounds in Example 1-1 was changed to YL-6121:YL6677=95:5 (epoxy equivalent ratio).

[0103] (Examples 1-3) A phenoxy resin was obtained in the same manner as in Example 1-1, except that the mixing ratio of the epoxy compounds in Example 1-1 was changed to YL-6121:YL6677=92.5:7.5 (epoxy equivalent ratio).

[0104] (Example 2-1) 64 parts by weight of epoxy compound (YL6121:HP-4770 = 95:5 (epoxy equivalent ratio)), 30 parts by weight of 2,7-dihydroxynaphthalene, 0.05 parts by weight of triphenylphosphine (TPP), and 7 parts by weight of solvent (cyclohexanone) were added to a reactor and melt-mixed at 100-110°C for 1 hour. The mixture was then heated to 150°C and reacted at that temperature while removing the solvent under reduced pressure. Once the target molecular weight was confirmed by GPC, the reaction was terminated to obtain a phenoxy resin. The reaction was carried out for 12 hours. After the reaction, 100 parts by weight of dimethylformamide was added to the resin to dissolve the resin, and the resin was cooled to room temperature. After cooling, the mixture was purified by reprecipitation using methanol to obtain 100 parts by weight of a phenoxy resin.

[0105] (Example 2-2) A phenoxy resin was obtained in the same manner as in Example 2-1, except that the ratio of the epoxy compounds in Example 2-1 was changed to YL-6121:HP-4770=92.5:7.5 (epoxy equivalent ratio).

[0106] Example 3 64 parts by weight of epoxy compound (YL6121:TEPIC-S = 95:5 (epoxy equivalent ratio)), 30 parts by weight of 2,7-dihydroxynaphthalene, 0.05 parts by weight of triphenylphosphine (TPP), and 7 parts by weight of solvent (cyclohexanone) were added to a reactor and melt-mixed at 100-110°C for 1 hour. The mixture was then heated to 150°C and reacted at that temperature while removing the solvent under reduced pressure. GPC confirmed that the target molecular weight had been achieved, and the reaction was terminated to obtain a phenoxy resin. 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 the resin was cooled to room temperature. After cooling, the mixture was purified by reprecipitation using methanol to obtain 100 parts by weight of a phenoxy resin.

[0107] (Comparative Example 1) 64 parts by weight of epoxy compound (YL-6121), 30 parts by weight of 2,7-dihydroxynaphthalene, 0.05 parts by weight of triphenylphosphine (TPP), and 7 parts by weight of solvent (cyclohexanone) were added to a reactor and melt-mixed at 100-110°C for 1 hour. The mixture was then heated to 150°C and reacted at that temperature while removing the solvent under reduced pressure. Once the target molecular weight was confirmed by GPC, the reaction was terminated to obtain a phenoxy resin. The reaction was carried out for 15 hours. After the reaction, 100 parts by weight of dimethylformamide was added to the resin to dissolve the resin, and the resin was cooled to room temperature. After cooling, the mixture was purified by reprecipitation using methanol to obtain 100 parts by weight of a phenoxy resin.

[0108] The physical properties of the phenoxy resins of the examples and comparative examples were measured by the following methods. (molecular weight, dispersity, and peak area) The GPC measurement conditions are as follows. Tosoh Corporation gel permeation chromatography system HLC-8320GPC Column: Tosoh Corporation TSK-GEL GMH, G2000H, SuperHM-M Detector: RI detector for liquid chromatography ·Measurement temperature: 40℃ Solvent: THF Sample concentration: 2.0 mg / ml The weight average molecular weight (Mw), number average molecular weight (Mn), and polydispersity index (PDI: Mw / Mn) were calculated using polystyrene-equivalent values ​​obtained from the calibration curve of standard polystyrene (PS) obtained by GPC measurement. Based on the molecular weight data obtained by the GPC measurement, the area ratio (%) of the peak area corresponding to the low molecular weight phenoxy resin with Mw of 1k or less contained in the entire phenoxy resin to be measured was calculated, assuming the total area of ​​the molecular weight distribution obtained by the GPC measurement to be 100%. The results are shown in Table 1.

[0109] (thermal conductivity) - Preparation of phenoxy resin molded body A mixture of 100 parts by weight of each phenoxy resin of Examples 1 and 2 or Comparative Example 1 and 2 parts by weight of a catalyst (2-methylimidazole) was placed in a mold coated with a release agent and compression molded at 180°C for 30 minutes to obtain a resin molded product with a diameter of 10 mm and a thickness of 1 mm. This was then cured in an oven at 180°C for 180 minutes to obtain a resin molded product (a sample for measuring thermal conductivity).

[0110] -Measurement of thermal conductivity of molded products The obtained resin molded body was cut into a 10 mm diameter x 1 mm thick test piece for thickness direction measurement. Next, the thermal diffusion coefficient (α) of the plate-shaped test piece in the thickness direction was measured by the laser flash method using a Xe flash analyzer TD-1RTV manufactured by ULVAC. The measurement was carried out under atmospheric conditions at 25°C. The thermal conductivity of the resin molded article was calculated from the measured values ​​of the thermal diffusion coefficient (α), specific heat (Cp), and density (ρ) according to the following formula. The results are shown in Table 1. Thermal conductivity [W / m K]=α[m 2 / s]×Cp[J / kg·K]×ρ[g / cm 3 ]

[0111] [Table 1]

[0112] All of the phenoxy resin molded articles obtained in the examples had higher thermal conductivity than that of Comparative Example 1. [Explanation of symbols]

[0113] 100 Metal base board 101 Metal substrate 102 Insulating layer 103 Metal layer

Claims

1. a bifunctional epoxy compound (A) having two epoxy groups; a polyfunctional epoxy compound (B) having three or more epoxy groups; a polyfunctional phenol compound (C) having at least two phenolic hydroxyl groups, The bifunctional epoxy compound (A) includes a compound represented by formula (d-EP): 【Chemistry 1】 X in the formula (d-EP) is a divalent organic group having a mesogenic skeleton represented by formula (2), 【Chemistry 2】 In formula (2), R １ ~R ８ are independently a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, * represents the linking position, The polyfunctional phenol compound (C) includes at least one selected from the compounds represented by formulas (p1) to (p17), 【Transformation 3】 【Chemistry 4】 【Transformation 5】 【Transformation 6】 【Transformation 7】 【Transformation 8】 In formulas (p1) to (p17), R independently represents a hydrogen atom, an alkoxy group having 1 to 4 carbon atoms, or a linear or branched alkyl group having 1 to 6 carbon atoms.

2. 2. The phenoxy resin according to claim 1, wherein the polyfunctional epoxy compound (B) comprises at least one selected from a trisphenolmethane type epoxy resin, a naphthalene type epoxy compound, and a triazine type epoxy compound.

3. In the group represented by formula (2), R １ , R ４ , R ５ , and R ８ is an alkyl group having 1 to 6 carbon atoms, and R ２ , R ３ , R ６ , and R ７ The phenoxy resin according to claim 1 or 2, wherein is a hydrogen atom.

4. In the group represented by formula (2), R １ , R ４ , R ５ , and R ８ is a methyl group, and R ２ , R ３ , R ６ , and R ７ The phenoxy resin according to claim 1 or 2, wherein is a hydrogen atom.

5. In the group represented by formula (2), R １ ~R ８ The phenoxy resin according to claim 1 or 2, wherein all of are hydrogen atoms.

6. The phenoxy resin according to any one of claims 1 to 5, wherein the polyfunctional epoxy compound (B) has an epoxy equivalent of 50 g / eq or more and 300 g / eq or less.

7. The phenoxy resin according to any one of claims 1 to 6, wherein the polyfunctional epoxy compound (B) comprises at least one epoxy compound selected from the group consisting of formulas (m1) to (m4): 【Chemistry 9】 【Chemistry 10】 In formulas (m1) to (m3), R １１ ~R １３ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and n1 in formula (m1) is an integer of 0 to 4.

8. The phenoxy resin according to any one of claims 1 to 7, wherein the difunctional epoxy compound (A) further contains an epoxy compound represented by formula (EP1): 【Chemistry 11】 In formula (EP1), R １４ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

9. 9. The phenoxy resin according to claim 1, comprising a structural unit derived from the difunctional epoxy compound (A), a structural unit derived from the polyfunctional epoxy compound (B), and a structural unit derived from the polyfunctional phenol compound (C).

10. The phenoxy resin according to any one of claims 1 to 9, which has a weight average molecular weight of 1,000 or more and 10,000 or less.

11. The phenoxy resin according to any one of claims 1 to 10, wherein a cured product of the phenoxy resin has a thermal conductivity of 0.3 W / (m·K) or more.

12. A thermosetting resin composition comprising the phenoxy resin according to any one of claims 1 to 11.

13. The thermosetting resin composition of claim 12, further comprising a thermally conductive filler.

14. The thermosetting resin composition according to claim 12 or 13, further comprising a solvent.

15. A thermally conductive sheet formed from the thermosetting resin composition according to any one of claims 12 to 14.

16. A resin substrate comprising a cured product of the thermally conductive sheet according to claim 15.

17. An electronic device comprising the resin substrate according to claim 16.

18. a metal layer; a resin layer laminated on at least one surface of the metal layer, A laminate, wherein the resin layer comprises a cured product of the thermally conductive sheet according to claim 15.

19. An electronic device comprising the laminate of claim 18.

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