Phenoxy resin and method for producing the same, and thermosetting resin composition, resin sheet, metal base substrate, and electronic device

Abstract

To provide a phenoxy resin that exhibits high thermal conductivity, and a resin composition that employs the phenoxy resin.SOLUTION: A phenoxy resin has a structure represented by formula (1). In formula (1), n represents an integer of 2 to 50; between X and Y, one is a divalent group in which three rings consisting of two benzene rings (one of which is optionally substituted with an alkyl group having 1 to 4 carbon atoms) and a cyclohexene ring, cyclohexadiene ring, or benzene ring between them are 1,4-bonded, and the other is a divalent organic group having a mesogenic skeleton.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a phenoxy resin, a method for producing the phenoxy resin, a thermosetting resin composition containing the phenoxy resin, a resin sheet made of the thermosetting resin composition, an electronic device including a cured product of the resin sheet as a thermally conductive sheet, a metal base substrate including a cured product of the resin sheet, and an electronic device including the metal base substrate. [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] As an example of this type of technology, Patent Document 1 proposes a thermally conductive epoxy resin composition and a molded product thereof, in which bisphenol A epoxy resin is blended with scaly or spherical boron nitride particles as thermally conductive particles. It has also been proposed to improve the thermal conductivity and heat resistance of the epoxy resin itself (see, for example, Patent Document 2). Patent Document 2 proposes an insulating composition with improved thermal conductivity by polymerizing a liquid crystalline epoxy resin having a mesogenic group. [Prior art documents] [Patent documents]

[0005] [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]

[0006] However, as a result of investigations by the present inventors, it has been found that conventional resin compositions have room for further improvement in terms of solubility in solvents and thermal conductivity. [Means for solving the problem]

[0007] 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.

[0008] According to the present invention, there are provided a phenoxy resin and a method for producing the same, as well as a thermosetting resin composition, a resin sheet, a metal base substrate, and an electronic device, as shown below. [1] A phenoxy resin having a structure represented by formula (1), [ka] In formula (1), n is a number representing a repeating unit and represents an integer of 2 to 50; X is a divalent organic group having a mesogenic skeleton, or a divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5), Y is a divalent organic group having a mesogenic skeleton, or a divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5), provided that when one of X and Y is a divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5), the other is a divalent organic group having a mesogenic skeleton; [ka] In equations (tp1), (tp2), (tp3), (tp4) and (tp5), R represents an alkyl group having 1 to 4 carbon atoms; m represents 0 or an integer of 1 to 3; * indicates the linking position. Phenoxy resin. [2] The phenoxy resin according to item [1], The phenoxy resin has an epoxy equivalent of 300 g / eq or more and 1000 g / eq or less. [3] The phenoxy resin according to item [1] or [2], The phenoxy resin has a weight average molecular weight of 3,000 or more and 10,000 or less. [4] The phenoxy resin according to any one of items [1] to [3], The divalent organic group having a mesogenic skeleton includes a divalent group represented by formula (2): [ka] In equation (2), R 1 ~R 8 each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms; * indicates the linkage position. Phenoxy resin. [5] The phenoxy resin according to item [4], In the group represented by formula (2), R 1 , R 4 , R 5 , and R 8 is an alkyl group having 1 to 4 carbon atoms, and R 2 , R 3 , R 6 , and R 7 is a hydrogen atom, phenoxy resin. [6] The phenoxy resin according to item [4], In the group represented by formula (2), R 1 , R 4 , R 5 , and R8 is a methyl group, and R 2 , R 3 , R 6 , and R 7 is a hydrogen atom, phenoxy resin. [7] The phenoxy resin according to item [4], In the group represented by formula (2), R 1 ~R 8 Phenoxy resin, in which all of the atoms are hydrogen. [8] The phenoxy resin according to any one of items [1] to [7], In the divalent groups represented by the formulae (tp1), (tp2), (tp3), (tp4) and (tp5), m is 1, R is a phenoxy resin, which is located at the ortho position relative to the linking position (*) on the benzene ring to which it is linked. [9] The phenoxy resin according to any one of items [1] to [8], A phenoxy resin having a thermal conductivity of 0.3 W / (m·K) or more after curing.

[10] A thermosetting resin composition comprising the phenoxy resin according to any one of items [1] to [9].

[11] The thermosetting resin composition according to item

[10] , further comprising a thermally conductive filler.

[12] A resin sheet made of the thermosetting resin composition according to item

[10] .

[13] a heat generating member; A heat dissipation member; a thermally conductive sheet provided between the heat-generating component and the heat-dissipating component, The thermally conductive sheet is made of a cured resin sheet according to item

[12] .

[14] A metal substrate; a thermally conductive sheet; A metal base substrate comprising, in this order, The thermally conductive sheet is a metal base substrate made of a cured resin sheet according to item

[12] .

[15] An electronic device comprising the metal base substrate according to item

[14] .

[16] A method for producing a phenoxy resin having a structure represented by formula (1), [ka] In formula (1), n is a number representing a repeating unit and represents an integer of 2 to 50; X is a divalent organic group having a mesogenic skeleton, or a divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5), Y is a divalent organic group having a mesogenic skeleton, or a divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5), provided that when one of X and Y is a divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5), the other is a divalent organic group having a mesogenic skeleton; [ka] In equations (tp1), (tp2), (tp3), (tp4) and (tp5), R represents an alkyl group having 1 to 4 carbon atoms; m represents 0 or an integer of 1 to 3; * indicates the linkage position, The method includes a step of reacting a dihydroxy compound (a) represented by formula (DH) with a bifunctional epoxy compound (b) having two epoxy groups represented by formula (d-EP), [ka] [ka] In formula (DH), Y has the same meaning as Y in formula (1), In formula (d-EP), X has the same meaning as X in formula (1). Method for producing phenoxy resin.

[17] A method for producing the phenoxy resin according to item

[16] , The divalent organic group having a mesogenic skeleton includes a divalent group represented by formula (2): [ka] In equation (2), R 1 ~R 8 each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms; * indicates the linkage position. Manufacturing method of phenoxy resin.

[18] A method for producing the phenoxy resin according to item

[17] , In the group represented by formula (2), R 1 , R 4 , R 5 , and R 8 is an alkyl group having 1 to 4 carbon atoms, and R 2 , R 3 , R 6 , and R 7 is a hydrogen atom, a method for producing phenoxy resin.

[19] A method for producing the phenoxy resin according to item

[17] , 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 is a hydrogen atom, a method for producing phenoxy resin.

[20] A method for producing the phenoxy resin according to item

[17] , In the group represented by formula (2), R 1 ~R 8 A method for producing phenoxy resin, wherein all of the above are hydrogen atoms.

[21] A method for producing the phenoxy resin according to any one of items

[16] to

[20] , In the divalent groups represented by the formulae (tp1), (tp2), (tp3), (tp4) and (tp5), m is 1, A method for producing a phenoxy resin, wherein R is located at the ortho position relative to the linking position (*) on the benzene ring to which it is linked. [Effects of the Invention]

[0009] 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]

[0010] [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. [Figure 2] 1 is a schematic cross-sectional view showing the configuration of an electronic device using a metal base substrate according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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 descriptions thereof will be omitted where appropriate. Furthermore, unless otherwise specified, "~" indicates "above" to "below."

[0012] [Phenoxy resin] The phenoxy resin of this embodiment has a structure represented by the following formula (1).

[0013] [ka]

[0014] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. In formula (1), n is a number representing a repeating unit and represents an integer of 2 to 50; X is a divalent organic group having a mesogenic skeleton, or a divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5), Y is a divalent organic group having a mesogenic skeleton, or a divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5), provided that when one of X and Y is a divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5), the other is a divalent organic group having a mesogenic skeleton;

[0015] [ka]

[0016] In equations (tp1), (tp2), (tp3), (tp4) and (tp5), R represents an alkyl group having 1 to 4 carbon atoms; m represents 0 or an integer of 1 to 3; * indicates the linkage position.

[0017] The phenoxy resin of this embodiment has a structure represented by formula (1). The divalent organic group represented by "X" in formula (1) is a divalent organic group having a mesogenic skeleton or a divalent group represented by the above formula (tp1), (tp2), (tp3), (tp4), or (tp5). The divalent group represented by "Y" in formula (1) is a divalent organic group having a mesogenic skeleton or a divalent group represented by formula (tp1), (tp2), (tp3), (tp4), or (tp5). However, when one of "X" and "Y" is a divalent group represented by formula (tp1), (tp2), (tp3), (tp4), or (tp5), the other is a divalent organic group having a mesogenic skeleton. Due to the structure of the phenoxy resin of this embodiment, its cured product has high thermal conductivity. Furthermore, the phenoxy resin of the present embodiment has the above structure, and therefore has excellent solubility in organic solvents such as cyclohexane and dimethylformamide, and therefore is easy to handle and process.

[0018] In the divalent groups represented by the above formulae (tp1), (tp2), (tp3), (tp4) and (tp5) constituting the X group or the Y group in formula (1), R represents an alkyl group having 1 to 4 carbon atoms, specifically a methyl group, an ethyl group, a propyl group or a butyl group, and the propyl group or the butyl group may be linear or branched.

[0019] In one embodiment, in the divalent groups represented by the above formulae (tp1), (tp2), (tp3), (tp4) and (tp5), R is located at the ortho position relative to the linking position (*) on the benzene ring to which it is linked.

[0020] In one embodiment, the mesogenic skeleton constituting the X group or Y group in formula (1) may be a biphenyl skeleton, a naphthalene skeleton, a phenylbenzoate skeleton, an azobenzene skeleton, a stilbene skeleton, a cyclohexylbenzene skeleton, or a derivative thereof. When the X group or the Y group has the above mesogenic skeleton, the phenoxy resin of this embodiment may have high thermal conductivity.

[0021] In one embodiment, one of the X group and the Y group in formula (1) is a group represented by formula (2). By including a structure having a mesogenic skeleton represented by formula (2), the phenoxy resin has high thermal conductivity and excellent heat resistance.

[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 a linking position. Multiple X groups or Y groups in formula (1) may be the same or different from each other.

[0024] In one embodiment, the group represented by formula (2) is preferably R 1 , R 4 , R5 , and R 8 is an alkyl group having 1 to 4 carbon atoms, and R 2 , R 3 , R 6 , and R 7 is a group in which R is a hydrogen atom. 1 , R 4 , R 5 , and R 8 is an alkyl group having one carbon atom (methyl group), and R 2 , R 3 , R 6 , and R 7 is a hydrogen atom (referred to as a "tetramethylbiphenyl group") is preferred in that the resulting phenoxy resin can achieve an excellent balance between thermal conductivity and heat resistance.

[0025] In one embodiment, the group represented by formula (2) is R 1 ~R 8 may be a group in which all of the groups are hydrogen atoms (referred to as a "biphenyl group"). By having such a group, the phenoxy resin has excellent thermal conductivity and heat resistance.

[0026] In one embodiment, the group represented by formula (2) may contain 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.

[0027] The phenoxy resin represented by formula (1) may contain, in addition to the above-mentioned X group and Y group, other groups to the extent that they do not affect the properties of the phenoxy resin.

[0028] In one embodiment, the phenoxy resin of the present invention has a structure in which, in formula (1), X is a divalent organic group having the above-described mesogenic skeleton, and Y is a divalent group represented by formula (tp1), (tp2), (tp3), (tp4), or (tp5). A phenoxy resin having the above structure is referred to as "phenoxy resin (A)" in this specification.

[0029] In one embodiment, the phenoxy resin of the present invention has a structure in which, in formula (1), X is a divalent group represented by the above formula (tp1), (tp2), (tp3), (tp4), or (tp5), and Y is a divalent organic group having a mesogenic skeleton as described above. The phenoxy resin having the above structure is referred to as "phenoxy resin (B)" in this specification.

[0030] The weight-average molecular weight (Mw) of the phenoxy resin of this embodiment is, for example, 3,000 to 10,000, preferably 3,500 to 9,000, and more preferably 4,000 to 8,000. 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.

[0031] In this embodiment, the weight-average molecular weight 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.

[0032] 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

[0033] The polydispersity (Mw / Mn) of the phenoxy resin is, for example, 1.00 to 8.00, preferably 2.00 to 7.50, and more preferably 2.50 to 7.00. By setting the polydispersity within the above range, the thermal conductivity and fluidity of the phenoxy resin can be further improved.

[0034] 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%, preferably 10% 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.

[0035] From the viewpoint of the effects of the present invention, the epoxy equivalent of the phenoxy resin is 300 to 1000 g / eq, preferably 350 to 900 g / eq, and more preferably 400 to 850 g / eq.

[0036] The melt viscosity of the phenoxy resin at 180°C is 100 mPa·s or less, preferably 50 mPa·s or less, which provides excellent moldability and excellent processing stability when the phenoxy resin is processed into a sheet or film.

[0037] The structure of the phenoxy resin of the present invention can be adjusted by selecting the raw material monomers used in the production thereof and the production conditions.

[0038] The phenoxy resin of this embodiment, having the above-described structure, can improve the thermal conductivity of the cured product. The thermal conductivity of the cured product of the phenoxy resin is, for example, 0.30 W / (m·K) or more, preferably 0.35 W / (m·K) or more, and more preferably 0.40 W / (m·K) or more.

[0039] [Method of manufacturing phenoxy resin] The phenoxy resin represented by formula (1) of the present embodiment can be produced by reacting a dihydroxy compound (a) represented by formula (DH) with a bifunctional epoxy compound (b) having two epoxy groups represented by formula (d-EP).

[0040] [ka]

[0041] [ka]

[0042] In formula (DH), Y has the same meaning as X in formula (1). In formula (d-EP), X has the same meaning as Y in formula (1).

[0043] 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.

[0044] In one embodiment, a phenoxy resin (phenoxy resin (A)) having a structure in which, in formula (1), X is the above-mentioned divalent organic group having a mesogenic skeleton and Y is the divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5) can be produced by reacting a dihydroxy compound (a) represented by formula (DH) in which Y is a divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5) with a bifunctional epoxy compound (b) having two epoxy groups represented by formula (d-EP) in which X is the above-mentioned divalent organic group having a mesogenic skeleton.

[0045] Examples of the dihydroxy compound (a) represented by formula (DH) used to produce the phenoxy resin (A) include: 1,4-bis(4-hydroxyphenyl)-1-cyclohexene, 1-(3-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1- cyclohexene, 1-(2-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(3-ethyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(2-ethyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(3-n-propyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(2-n-propyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(3-isopropyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(2-isopropyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(3-n-butyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(2-n-butyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(3-isobutyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(2-isobutyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(3-s-butyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(2-s-butyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(3-t-butyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(2-t-butyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(3-phenyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene 1-(3,6-dimethyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(3,5-dimethyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(2,3,6-dimethyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(2,3,5-dimethyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(3-isopropyl-6-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(3-isopropyl-5-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(3-t-butyl-6-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(3-t-butyl-5-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(3,5-di-t-butyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(3,5-diisopropyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl) (nyl)-1-cyclohexene, 1,4-bis(4-hydroxyphenyl)benzene, 1-(3-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(2-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(3-ethyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(2-ethyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(3-n-propyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(2-n-propyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(3-isopropyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(2-isopropyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(3-n-butyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(2-n-butyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(3-isobutyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(2-isobutyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(3-s-butyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(2-s-butyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(3-t-butyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(2-t-butyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(3-phenyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene 1-(3,6-dimethyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(3,5-dimethyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(2,3,6-dimethyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(2,3,5-dimethyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(3-isopropyl-6-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(3-isopropyl-5-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(3-t-butyl-6-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(3-t-butyl-5-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(3,5-di-t-butyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(3,5-diisopropyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl) phenyl)benzene and the like.

[0046] Among these, the dihydroxy compound (a) is 1,4-bis(4-hydroxyphenyl)-1-cyclohexene, 1-(3-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1-(3,5-dimethyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene, 1,4-bis(4-hydroxyphenyl)-1-benzene, 1-(3-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene, 1-(3,5-dimethyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene and the like are preferred.

[0047] Examples of the bifunctional epoxy compound (b) represented by the formula (d-EP) used to produce the phenoxy resin (A) include: 4,4'-diglycidylbiphenyl, 4,4'-diglycidyl-3,3',5,5'-tetramethylbiphenyl, Examples include 1,6-bis(glycidyloxy)naphthalene. These compounds may be used singly or in combination of two or more.

[0048] 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.

[0049] 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 monomers.

[0050] 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.

[0051] Specifically, a bifunctional epoxy compound (a), a bifunctional phenol compound (b), a reaction catalyst, and optionally a reaction solvent are added and melt-mixed under stirring at a heating temperature of about 90 to 120°C, a mixing time of about 30 minutes to 2 hours, and normal pressure.

[0052] After melt mixing, the mixed solution is heated and the polymerization reaction is carried out at a predetermined reaction temperature under reduced pressure or normal pressure at a reaction temperature of about 140 to 180°C, a reaction time of about 2 to 10 hours, and a reaction pressure of about 1 to 760 Torr.

[0053] 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.

[0054] [Thermosetting resin composition] Hereinafter, a thermosetting resin composition using the phenoxy resin of the present embodiment will be described. The thermosetting resin composition of the present embodiment contains the phenoxy resin described above and may contain other components depending on its application. Hereinafter, components that can constitute the thermosetting resin composition of the present embodiment will be described.

[0055] (phenoxy resin) The thermosetting resin composition of this embodiment contains the phenoxy resin of the present invention. When the thermosetting resin composition of this embodiment is used, for example, in 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.

[0056] (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.

[0057] 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.

[0058] The amount of the thermally conductive filler to be blended is, for example, 40% by mass to 90% by mass, and preferably 50% by mass to 80% by mass, based on the total solid content of the thermosetting resin composition. By using the thermally conductive filler in an amount within the above range, the handleability of the resulting resin composition can be maintained while improving the thermal conductivity of the cured product. The thermally conductive filler may also be surface-treated with a silane coupling agent.

[0059] (cyanate ester resin) The thermosetting resin composition of this embodiment may contain a cyanate ester resin. The cyanate ester resin acts as a curing agent for the phenoxy resin of the present invention represented by formula (1). The cyanate ester resin reacts with the phenoxy resin of the present invention through a reaction mechanism that does not generate hydroxyl groups. Therefore, the resulting cured product does not contain hydroxyl groups and has high heat resistance.

[0060] The cyanate ester resin used can include one or more selected from novolac cyanate ester resins; bisphenol cyanate ester resins such as bisphenol A cyanate ester resins, bisphenol E cyanate ester resins, and tetramethylbisphenol F cyanate ester resins; naphthol aralkyl cyanate ester resins obtained by reacting naphthol aralkyl phenol resins with cyanogen halides; dicyclopentadiene cyanate ester resins; and biphenylene skeleton-containing phenol aralkyl cyanate ester resins. Among these, from the viewpoint of the effects of the present invention, it is more preferable to include at least one of novolac cyanate ester resins and naphthol aralkyl cyanate ester resins, and it is particularly preferable to include novolac cyanate ester resins.

[0061] As the novolac type cyanate ester resin, for example, a resin represented by formula (I) can be used.

[0062] [ka]

[0063] The average repeating unit number n of the novolac cyanate ester resin represented by formula (I) is any integer. The average repeating unit number n is not particularly limited, but is preferably 1 or more, more preferably 2 or more. When the average repeating unit number n is equal to or greater than the above-mentioned lower limit, the heat resistance of the novolac cyanate resin is improved, and the elimination and volatilization of oligomers upon heating can be further suppressed. Furthermore, the average repeating unit number n is not particularly limited, but is preferably 10 or less, more preferably 7 or less. When n is equal to or less than the above-mentioned upper limit, the melt viscosity can be suppressed from increasing, and the moldability of the resin sheet can be improved.

[0064] As the cyanate ester resin, a naphthol aralkyl cyanate ester resin represented by formula (II) is also preferably used. The naphthol aralkyl cyanate resin represented by formula (II) is obtained by condensing a naphthol aralkyl 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, or the like, with a cyanogen halide. The repeating unit n in formula (II) is preferably an integer of 10 or less. A repeating unit n of 10 or less can produce a more uniform resin sheet. Furthermore, intramolecular polymerization is less likely to occur during synthesis, improving separation during water washing and tending to prevent a decrease in yield.

[0065] [ka]

[0066] In 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.

[0067] The cyanate ester resin is used in an amount of, for example, 10% by mass to 70% by mass, preferably 15% by mass to 60% by mass, and more preferably 20% by mass to 50% by mass, based on the total solid content of the thermosetting resin composition excluding the thermally conductive filler. This ensures sufficient curability of the resulting thermosetting resin composition, and allows for the production of a resin sheet with excellent thermal conductivity.

[0068] (epoxy resin) The thermosetting resin composition of this embodiment may contain an epoxy resin other than the phenoxy resin of the present invention. The use of an epoxy resin can improve the curability of the resulting thermosetting resin composition. Examples of epoxy resins that can be used include glycidyl ethers of bisphenol A, F, S, AD, etc., hydrogenated bisphenol A, phenol novolac, cresol novolac, bisphenol A novolac, naphthalene, biphenol, dihydroxypentadiene, triphenylmethane, phenol novolac, cresol novolac, and hydroquinone. At least one of these epoxy resins can be used. From the viewpoint of the effects of the present invention, the epoxy resin preferably contains at least one selected from naphthalene-type glycidyl ethers, biphenol-type glycidyl ethers, dihydroxypentadiene-type glycidyl ethers, and hydroquinone-type glycidyl ethers.

[0069] The epoxy resin preferably contains an epoxy resin containing a mesogenic skeleton, which can further enhance the thermal conductivity (heat dissipation) of the cured resin. It is believed that epoxy resins containing a mesogenic skeleton form a higher-order structure (liquid crystal phase or crystalline phase) due to the mesogenic skeleton when cured. It is believed that heat is transferred through this higher-order structure, further enhancing thermal conductivity (heat dissipation). The presence of the higher-order structure in the cured product can be confirmed by observation with a polarizing microscope.

[0070] The mesogenic skeleton may be any skeleton that facilitates the development of liquid crystallinity or crystallinity through intermolecular interactions. The mesogenic skeleton preferably includes 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.

[0071] The epoxy resin particularly preferably contains a condensed polycyclic aromatic hydrocarbon skeleton, and particularly preferably contains a naphthalene skeleton.

[0072] For example, in the case of a biphenyl skeleton (-CH-CH-), the central carbon-carbon single bond in the structure may "rotate" due to thermal motion at high temperatures, potentially resulting in a decrease in liquid crystallinity. Similarly, in the case of a phenylbenzoate skeleton (-CH-COO-CH-), the ester bond may rotate at high temperatures. However, in principle, such rotation does not cause a decrease in liquid crystallinity in a condensed polycyclic aromatic hydrocarbon skeleton such as a naphthalene skeleton. In other words, the inclusion of a condensed polycyclic aromatic hydrocarbon skeleton in an epoxy resin can further improve the heat dissipation properties of the resulting cured resin in high-temperature environments.

[0073] Furthermore, by employing a naphthalene skeleton as the polycyclic aromatic hydrocarbon skeleton, the epoxy resin can be prevented from becoming too rigid while still achieving the above-mentioned advantages. This is because the naphthalene skeleton is relatively small for a mesogenic skeleton. The fact that the epoxy resin does not become too rigid is advantageous in that stress during curing of the thermosetting resin composition of this embodiment is more easily alleviated, thereby preventing cracks and the like.

[0074] The epoxy resin preferably contains a di- or higher functional epoxy resin. In other words, it is preferable that one molecule of the epoxy resin contains two or more epoxy groups. The number of functional groups of the epoxy resin is preferably 2 to 6, and more preferably 2 to 4. From the viewpoint of the effects of the present invention, the epoxy resin in this embodiment preferably contains at least one epoxy resin selected from compounds represented by the following formula:

[0075] [ka]

[0076] The epoxy equivalent of the epoxy resin is, for example, 100 to 200 g / eq, preferably 105 to 190 g / eq, and more preferably 110 to 180 g / eq. By using an epoxy resin with an appropriate epoxy equivalent, it is possible to control the curability of the resulting thermosetting resin composition and optimize the physical properties of the cured product.

[0077] In one embodiment, the epoxy resin preferably further contains another epoxy resin that is liquid or semi-solid at room temperature (23° C.), and more specifically, it is preferable that a part or all of the epoxy resin is liquid or semi-solid at 23° C. By using a liquid or semi-solid epoxy resin, it becomes easier to form a cured product in a desired shape.

[0078] In one embodiment, the epoxy resin preferably contains a combination of an epoxy resin that is liquid at room temperature and an epoxy resin that is semi-solid or solid at room temperature, which improves the moldability of the resulting thermosetting resin composition.

[0079] The epoxy resin is, for example, 5% by mass to 50% by mass, preferably 7% by mass to 45% by mass, and more preferably 10% by mass to 40% by mass, based on the total solid content of the thermosetting resin composition excluding the thermally conductive filler. This ensures sufficient curability, and allows the production of a resin sheet with excellent thermal conductivity and insulation properties.

[0080] (other thermosetting resins) The thermosetting resin composition of this embodiment may contain other thermosetting resins besides the phenoxy resin and epoxy resin, as long as the effects of the present invention are not impaired. Examples of such other thermosetting resins include epoxy resins other than the phenoxy resin of this embodiment, 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 resins may be used alone or in combination of two or more.

[0081] (curing accelerator) The thermosetting resin composition of the present embodiment may contain a curing accelerator. The type and amount of the curing accelerator are not particularly limited, and an appropriate one can be selected from the viewpoints of reaction rate, reaction temperature, storage properties, etc.

[0082] Examples of curing accelerators that can be used include imidazoles, organic phosphorus compounds, tertiary amines, phenolic compounds, organic acids, etc. These may be used alone or in combination of two or more.

[0083] 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, and 1-cyanoethyl-2-phenylimidazolium trimellitate.

[0084] Examples of the organic phosphorus compound include triphenylphosphine, tri-p-tolylphosphine, tetraphenylphosphonium tetraphenylborate, triphenylphosphine triphenylborane, and 1,2-bis-(diphenylphosphino)ethane. Examples of the tertiary amines include triethylamine, tributylamine, 1,4-diazabicyclo[2.2.2]octane, and 1,8-diazabicyclo(5,4,0)undecene-7. Examples of the phenol compound include novolac phenolic resin, bisphenol A, nonylphenol, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, and allylphenol. Examples of the organic acid include acetic acid, benzoic acid, salicylic acid, and p-toluenesulfonic acid.

[0085] Among these, it is preferable to use a novolac type phenolic resin, since this can further enhance the curability of the resulting thermosetting resin composition.

[0086] The amount of the curing accelerator to be added is, for example, 0.01% by mass to 10% by mass, preferably 0.02% by mass to 7% by mass, and more preferably 0.05% by mass to 5% by mass, based on the total solid content of the thermosetting resin composition excluding the thermally conductive filler.

[0087] (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.

[0088] The thermosetting resin composition of the present embodiment may contain components other than the components described above, such as an antioxidant and a leveling agent.

[0089] [Method for producing thermosetting resin composition] The resin varnish (a thermosetting resin composition in varnish form) can be prepared by dissolving, mixing, and stirring the above 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 dispersion, high-speed shear dispersion, and rotation-revolution dispersion.

[0090] 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.

[0091] [Uses of thermosetting resin compositions] (resin sheet) The resin sheet of the present embodiment includes a carrier substrate and a resin layer formed on the carrier substrate and made of the thermosetting resin composition of the present embodiment. The resin sheet of the present embodiment can be used as a thermally conductive resin sheet used as a heat dissipation member.

[0092] 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.

[0093] 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.

[0094] (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.

[0095] (Metal base board) As an example of this embodiment, a metal base substrate 100 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. As shown in FIG.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] (Semiconductor Devices) The metal base substrate (heat dissipation and insulation member) 100 of the embodiment can be used in various applications that require heat dissipation and insulation, 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. As shown in FIG. A semiconductor element 201 is mounted on a metal layer 103 of a 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. The semiconductor element 201 is encapsulated on the metal base substrate 100 by an encapsulation resin layer 205 .

[0105] A heat sink 207 is provided on the metal substrate 101 side of the metal base substrate 100 via a thermally conductive layer 206 (thermal interface material (TIM)). The heat sink 207 is made of a material with excellent thermal conductivity, such as aluminum, iron, or copper. [Example]

[0106] EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these.

[0107] Example A [Preparation of phenoxy resin] Phenoxy resins A1 to A5 were prepared using the following method. The raw material monomers used in the preparation of the phenoxy resins are shown below. Dihydroxy compound a1: 1-(3-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-1-cyclohexene represented by the formula (DH1) [ka] Dihydroxy compound a2: 1-(3-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)benzene represented by the formula (DH2) [ka]

[0108] Epoxy compound b1: tetramethylbiphenyl-type epoxy resin represented by formula (3) ("YX4000" manufactured by Mitsubishi Chemical Corporation) [ka]

[0109] Epoxy compound b2: A biphenyl-type epoxy resin represented by formula (3) and formula (4) in a 1:1 ratio ("YL-6121" manufactured by Mitsubishi Chemical Corporation) [ka] Epoxy compound b3: an epoxy compound represented by formula (5) ("HP-4032" manufactured by DIC Corporation) [ka]

[0110] Example A1: Preparation of Phenoxy Resin 1 Epoxy compound b1 (69.5 parts by weight), dihydroxy compound a1 (28.5 parts by weight), triphenylphosphine (TPP) (0.04 parts by weight), and solvent (cyclohexanone) (2 parts by weight) were added to a reactor and melt-mixed at 110-120°C for 1 hour. The equivalent ratio (Ep / Ph) of epoxy compound b1 to dihydroxy compound a1 was 1.8. The resulting mixture was heated to 160°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 phenoxy resin 1. The reaction was carried out for 6 hours. The molten reactant was removed and cooled to room temperature. 215 parts by weight of phenoxy resin 1 represented by the following formula (1-1) (X in formula (1-1) is a structural unit derived from epoxy compound b1 of formula (3), Y is a structural unit derived from dihydroxy compound a1, and the weight average molecular weight Mw measured by GPC is 4400) was obtained.

[0111] [ka]

[0112] Example A2: Preparation of Phenoxy Resin 2 Epoxy compound b1 (68 parts by weight), dihydroxy compound a1 (30 parts by weight), triphenylphosphine (TPP) (0.04 parts by weight), and a solvent (cyclohexanone) (2 parts by weight) were added to a reactor and melt-mixed at 110 to 120°C for 1 hour. The equivalent ratio (Ep / Ph) of epoxy compound b1 to dihydroxy compound a1 was 1.7. The resulting mixture was heated to 160°C and reacted at that temperature while removing the solvent under reduced pressure. After confirming the target molecular weight by GPC, the reaction was terminated to obtain phenoxy resin 2. The reaction was carried out for 7 hours. The molten reaction product was removed and cooled to room temperature. 240 parts by weight of phenoxy resin 2 represented by the above formula (1-1) was obtained. (In formula (1-1), X is a structural unit derived from epoxy compound b1 of formula (3), Y is a structural unit derived from dihydroxy compound a1, and the weight-average molecular weight (Mw) measured by GPC was 4600.)

[0113] Example A3: Preparation of Phenoxy Resin 3 Epoxy compound b1 (30.2 parts by weight), epoxy compound b2 (45.3 parts by weight), dihydroxy compound a1 (22.5 parts by weight), triphenylphosphine (TPP) (0.04 parts by weight), and solvent (cyclohexanone) (2 parts by weight) were added to a reactor and melt-mixed at 110-120°C for 1 hour. The equivalent ratio (Ep / Ph) of the total of epoxy compound b1 and epoxy compound b2 to dihydroxy compound a1 was 1.7. The resulting mixture was heated to 160°C and reacted at that temperature while removing the solvent under reduced pressure. The target molecular weight was confirmed by GPC, and the reaction was terminated to obtain phenoxy resin 3. The reaction was carried out for 8 hours. The molten reactant was removed and cooled to room temperature. 215 parts by weight of phenoxy resin 3 represented by the above formula (1-1) (X in formula (1-1) is a mixture of a structural unit derived from epoxy compound b1 of formula (3) and a structural unit derived from epoxy compound b2 of formula (4), Y is a structural unit derived from dihydroxy compound a1, and the weight average molecular weight Mw measured by GPC is 4300) was obtained.

[0114] Example A4: Preparation of phenoxy resin 4 Epoxy compound b1 (35.1 parts by weight), epoxy compound b2 (32.4 parts by weight), dihydroxy compound a1 (30.5 parts by weight), triphenylphosphine (TPP) (0.04 parts by weight), and solvent (cyclohexanone) (2 parts by weight) were added to a reactor and melt-mixed at 110-120°C for 1 hour. The equivalent ratio (Ep / Ph) of the total of epoxy compound b1 and epoxy compound b2 to dihydroxy compound a1 was 1.7. The resulting mixture was heated to 160°C and reacted at that temperature while removing the solvent under reduced pressure. The target molecular weight was confirmed by GPC, and the reaction was terminated to obtain phenoxy resin 4. The reaction was carried out for 6 hours. The molten reactant was removed and cooled to room temperature. 213 parts by weight of phenoxy resin 4 represented by the above formula (1-1) (X in formula (1-1) is a mixture of a structural unit derived from epoxy compound b1 of formula (3) and a structural unit derived from epoxy compound b2 of formula (4), Y is a structural unit derived from dihydroxy compound a1, and the weight average molecular weight Mw measured by GPC is 4400) was obtained.

[0115] Example A5: Preparation of Phenoxy Resin 5 Epoxy compound b3 (65.8 parts by weight), dihydroxy compound a1 (32.2 parts by weight), triphenylphosphine (TPP) (0.04 parts by weight), and solvent (cyclohexanone) (2 parts by weight) were added to a reactor and melt-mixed at 110-120°C for 1 hour. The equivalent ratio (Ep / Ph) of epoxy compound b3 to dihydroxy compound a1 was 1.8. The resulting mixture was heated to 160°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 phenoxy resin 5. The reaction was carried out for 7 hours. The molten reactant was removed and cooled to room temperature. 227 parts by weight of phenoxy resin 5 represented by the above formula (1-1) (X in formula (1-1) is a mixture with a structural unit derived from epoxy compound b3 of formula (5), Y is a structural unit derived from dihydroxy compound a1, and the weight average molecular weight Mw measured by GPC is 4300) was obtained.

[0116] Example A6: Preparation of Phenoxy Resin 6 Epoxy compound b1 (67.4 parts by weight), dihydroxy compound a2 (30.6 parts by weight), triphenylphosphine (TPP) (0.04 parts by weight), and solvent (cyclohexanone) (2 parts by weight) were added to a reactor and melt-mixed at 110-120°C for 1 hour. The equivalent ratio (Ep / Ph) of epoxy compound b3 to dihydroxy compound a1 was 1.6. The resulting mixture was heated to 160°C and reacted at that temperature while removing the solvent under reduced pressure. After confirming the target molecular weight by GPC, the reaction was terminated to obtain phenoxy resin 5. The reaction was carried out for 7 hours. The molten reactant was removed and cooled to room temperature. 214 parts by weight of phenoxy resin 5 represented by the above formula (1-1) (X in formula (1-1) is a mixture with a structural unit derived from epoxy compound b3 of formula (5), Y is a structural unit derived from dihydroxy compound a1, and the weight average molecular weight Mw measured by GPC is 3900) was obtained.

[0117] Comparative Example A1: Preparation of Phenoxy Resin 7 A bisphenol A-type phenoxy resin (YP-55, manufactured by Mitsubishi Chemical Corporation) represented by the following formula (6) was used as phenoxy resin 7.

[0118] [ka]

[0119] [Physical property measurement of phenoxy resin] (epoxy equivalent) The epoxy equivalents of the phenoxy resins 1 to 7 obtained in Examples A1 to A6 and Comparative Example A1 were measured. The results are shown in Table 1.

[0120] (Solvent soluble (cyclohexanone)) Each of the phenoxy resins 1 to 7 obtained in Examples A1 to A6 and Comparative Example A1 was mixed with cyclohexanone and heated to 60°C to completely dissolve, yielding a cyclohexanone solution with a nonvolatile content of 30%. The solvent solubility of the phenoxy resin was determined based on whether the cyclohexanone solution was cloudy or not when cooled to room temperature (25°C). When the cyclohexanone solution was transparent when cooled to room temperature, it was rated as "A," and when the cyclohexanone solution was even slightly cloudy when cooled to room temperature, it was rated as "B." The results are shown in Table 1.

[0121] (thermal conductivity) Each of the phenoxy resins 1 to 7 obtained in Examples A1 to A6 and Comparative Example A1 was mixed with a curing accelerator 1 (2-methylimidazole) in the amounts shown in Table 1 to prepare a resin composition. The resulting resin composition 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 measuring 10 mm square and 1 mm thick. The product was then cured in an oven at 180°C for 180 minutes to obtain a resin molded product (a sample for measuring thermal conductivity). The obtained resin molded body was cut into a 10 mm square x 1 mm thick test piece for thickness direction measurement. The thermal diffusion coefficient (α) of the plate-shaped test piece in the thickness direction was measured by the Xe flash method using a NETZSCH Xe flash analyzer LFA467 HyperFlash. The measurement was performed under atmospheric conditions at 25°C. The measurements were carried out in an air atmosphere at 25°C. A higher thermal conductivity value indicates higher thermal conductivity. The measurement results are shown in Table 1.

[0122] [Table 1]

[0123] Example B [Preparation of thermosetting resin composition containing phenoxy resin] (Examples B1 to B6, Comparative Examples B1 to B3) A resin composition was obtained by mixing the components according to the formulation shown in Table 2. Details of each component in Table 2 are as follows.

[0124] (hardening agent) Hardener 1: Cyanate ester resin (Lonza, Primaset "PT-30") Curing agent 2: 4,4'-diaminodiphenyl sulfone (Tokyo Chemical Industry Co., Ltd.) (epoxy resin) Epoxy resin 1: Tetramethylbiphenyl type epoxy resin represented by formula (3) ("YX4000" manufactured by Mitsubishi Chemical Corporation) [ka] Epoxy resin 2: an epoxy compound represented by formula (5) ("HP-4032" manufactured by DIC Corporation) [ka]

[0125] Epoxy resin 3: bisphenol F type epoxy resin represented by formula (7) (DIC Corporation, EPICLON 830S) [ka]

[0126] (phenoxy resin) Phenoxy resin 1: Phenoxy resin 1 prepared in Example A1 Phenoxy resin 2: Phenoxy resin 2 prepared in Example A2 Phenoxy resin 3: Phenoxy resin 3 prepared in Example A3 Phenoxy resin 4: Phenoxy resin 4 prepared in Example A4 Phenoxy resin 5: Phenoxy resin 5 prepared in Example A5 Phenoxy resin 6: Phenoxy resin 6 prepared in Example A6 Phenoxy resin 7: Phenoxy resin 7 represented by formula (6) of Comparative Example A1 (curing accelerator) Curing accelerator 1: Novolac phenolic resin (Sumitomo Bakelite Co., Ltd., PR-55617) Curing accelerator 2: 2-methylimidazole (manufactured by Shikoku Chemicals Co., Ltd.) (thermal conductive filler) Thermally conductive particles 1: Agglomerated boron nitride (HP40, manufactured by Mizushima Ferroalloy Co., Ltd.)

[0127] (Measurement of physical properties of cured products) The cured products of the thermosetting resin compositions obtained above were measured for the following physical properties.

[0128] (thermal conductivity) -Making resin molded products The obtained thermosetting resin composition containing the thermally conductive filler was sandwiched between 0.018 mm copper foils and compression molded at 10 MPa at 180°C for 90 minutes to obtain a resin molded body (thermal conductivity measurement sample 1). A 10 mm square sample for thermal diffusivity measurement was cut out from the obtained molded body and used for thermal diffusivity measurement.

[0129] Density (specific gravity) of resin moldings The density (specific gravity) measurement was carried out in accordance with JIS K 6911 (general testing method for thermosetting plastics). Test pieces were cut out from the above resin molded body to a size of 2 cm length x 2 cm width. The density (specific gravity) (ρ) was measured in g / cm. 3 Let's say.

[0130] (porosity) The ratio of the measured specific gravity of the resin molded product to the theoretical specific gravity was calculated, and the result was subtracted from 1 to obtain the porosity.

[0131] Specific heat of resin molded body The specific heat (Cp) of the resin molded article obtained above was measured by the DSC method.

[0132] Measurement of thermal conductivity of resin moldings The obtained resin molded body was cut into 10 mm square test pieces for thickness measurement. The thermal diffusivity (α) of the plate-shaped test pieces in the thickness direction was measured by the transient method using a NETZSCH Xe flash analyzer LFA467 HyperFlash. The measurement was performed under atmospheric conditions at 25°C. The thermal conductivity of the resin molded body was calculated from the measured values ​​of thermal diffusion coefficient (α), specific heat (Cp), and density (ρ) according to the following formula. The results are shown in Table 2. Thermal conductivity [W / m K]=α[m 2 / s]×Cp[J / kg·K]×ρ[g / cm 3 ]

[0133] (glass transition temperature) After removing the copper foil from the obtained molded body, test pieces were cut into 8 mm wide strips. The test pieces were subjected to thermomechanical analysis using a dynamic viscoelasticity analyzer (Seiko Instruments Inc., DMS6100) at a temperature range of 0°C to 400°C and a heating rate of 5°C / min to measure the glass transition temperature. The glass transition temperature is measured in °C.

[0134] (volume resistivity) Each of the thermosetting resin composition molded articles with copper foil obtained above was etched to prepare a circular electrode with a guard, and the volume resistivity at 25°C and 175°C was measured. The unit of volume resistivity is Ω·cm. A higher volume resistivity value indicates better insulation.

[0135] (moisture absorption rate) The copper foil was removed from the resulting resin molded product by etching, and the product was left to stand at 30°C / 90% RH for 48 hours, and the moisture absorption rate (%) was calculated from the change in weight before and after the treatment.

[0136] (solder heat resistance) The obtained resin molded body was cut into 50 mm x 50 mm pieces using a grinder saw, and then etched to create samples with only half of the copper foil remaining, which were evaluated in accordance with JIS C 6481. The evaluation was carried out by immersing the samples in a solder bath at 300°C for 5 minutes and then examining the appearance for any abnormalities. The evaluation criteria were as follows: <Evaluation criteria> A: No abnormalities B: Abnormal (bulging areas throughout)

[0137] (Moisture absorption solder heat resistance (290℃ / 297℃)) The resulting resin molded body was cut into 50 mm x 50 mm pieces using a grinder saw, and then half of the surface was etched according to JIS C 6481 to prepare specimens. After leaving the specimens in an environment of 40°C and 90% humidity for two days, they were floated copper foil side down in a solder bath at 290°C or 297°C, and the presence or absence of external abnormalities was checked after one minute. The evaluation criteria were as follows. The results are shown in Table 2. <Evaluation criteria> A: No abnormalities B: Swelling (there are bulges all over the body)

[0138] [Table 2] [Explanation of symbols]

[0139] 100 Metal base board 101 Metal substrate 102 Insulating layer 103 Metal layer 200 Semiconductor device 201 Semiconductor elements 202 Adhesive layer 203 Bonding Wire 205 Sealing resin layer 206 Thermal Conduction Layer 207 Heatsink

Claims

1. A phenoxy resin having a structure represented by formula (1): 【Chemical 1】 In formula (1), n is the number of repeating units and is an integer of 2 to 50; X is a divalent organic group having a mesogenic skeleton, or a divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5), Y is a divalent organic group having a mesogenic skeleton, or a divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5), provided that when one of X and Y is a divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5), the other is a divalent organic group having a mesogenic skeleton; 【Chemistry 2】 In the formulas (tp1), (tp2), (tp3), (tp4) and (tp5), R represents an alkyl group having 1 to 4 carbon atoms; m represents 0 or an integer of 1 to 3; * indicates the linking position. Phenoxy resin.

2. The phenoxy resin according to claim 1, The phenoxy resin has an epoxy equivalent of 300 g / eq or more and 1000 g / eq or less.

3. The phenoxy resin according to claim 1, The phenoxy resin has a weight average molecular weight of 3,000 or more and 10,000 or less.

4. The phenoxy resin according to claim 1, The divalent organic group having a mesogenic skeleton includes a divalent group represented by formula (2): 【Chemistry 3】 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; * indicates the linkage position. Phenoxy resin.

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

6. The phenoxy resin according to claim 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 is a hydrogen atom, phenoxy resin.

7. The phenoxy resin according to claim 4, In the group represented by formula (2), R １ ~R ８ Phenoxy resin, in which all of the atoms are hydrogen.

8. The phenoxy resin according to claim 1, In the divalent groups represented by the formulae (tp1), (tp2), (tp3), (tp4) and (tp5), m is 1, R is a phenoxy resin, and is located at the ortho position relative to the linking position (*) on the benzene ring to which it is linked.

9. The phenoxy resin according to claim 1, A phenoxy resin having a thermal conductivity of 0.3 W / (m·K) or more after curing.

10. A thermosetting resin composition comprising the phenoxy resin according to any one of claims 1 to 9.

11. The thermosetting resin composition of claim 10, further comprising a thermally conductive filler.

12. A resin sheet comprising the thermosetting resin composition according to claim 10.

13. A heat-generating member; A heat dissipation member; a thermally conductive sheet provided between the heat-generating component and the heat-dissipating component, An electronic device, wherein the thermally conductive sheet is made of a cured resin sheet according to claim 12.

14. A metal substrate; a thermally conductive sheet; A metal base substrate comprising, in this order, A metal base substrate, wherein the thermally conductive sheet is made of a cured resin sheet according to claim 12.

15. An electronic device comprising the metal base substrate of claim 14.

16. A method for producing a phenoxy resin having a structure represented by formula (1), comprising: 【Chemistry 4】 In formula (1), n is the number of repeating units and is an integer of 2 to 50; X is a divalent organic group having a mesogenic skeleton, or a divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5), Y is a divalent organic group having a mesogenic skeleton, or a divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5), provided that when one of X and Y is a divalent group represented by formula (tp1), (tp2), (tp3), (tp4) or (tp5), the other is a divalent organic group having a mesogenic skeleton; 【Chemistry 5】 In the formulas (tp1), (tp2), (tp3), (tp4) and (tp5), R represents an alkyl group having 1 to 4 carbon atoms; m represents 0 or an integer of 1 to 3; * indicates the linking position, The method includes a step of reacting a dihydroxy compound (a) represented by formula (DH) with a bifunctional epoxy compound (b) having two epoxy groups represented by formula (d-EP), 【Chemistry 6】 【Chemistry 7】 In formula (DH), Y has the same meaning as X in formula (1), In formula (d-EP), X has the same meaning as Y in formula (1). Method for producing phenoxy resin.

17. A method for producing the phenoxy resin according to claim 16, comprising: The divalent organic group having a mesogenic skeleton includes a divalent group represented by formula (2): 【Chemistry 8】 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; * indicates the linking position. Manufacturing method of phenoxy resin.

18. A method for producing the phenoxy resin according to claim 17, In the group represented by formula (2), R １ , R ４ , R ５ , and R ８ is an alkyl group having 1 to 4 carbon atoms, and R ２ , R ３ , R ６ , and R ７ is a hydrogen atom, a method for producing phenoxy resin.

19. A method for producing the phenoxy resin according to claim 17, 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 is a hydrogen atom, a method for producing phenoxy resin.

20. A method for producing the phenoxy resin according to claim 17, In the group represented by formula (2), R １ ~R ８ A method for producing phenoxy resin, wherein all of the above are hydrogen atoms.

21. A method for producing the phenoxy resin according to claim 16, comprising: In the divalent groups represented by the formulae (tp1), (tp2), (tp3), (tp4) and (tp5), m is 1, A method for producing a phenoxy resin, wherein R is located at the ortho position relative to the linking position (*) on the benzene ring to which it is linked.

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