Thermosetting resin composition and electronic device

Abstract

To provide a thermosetting resin composition whose cured product has high thermal conductivity.SOLUTION: A thermosetting resin composition contains a bifunctional epoxy compound (A) having two epoxy groups, represented by formula (d-EP), and a bifunctional phenolic compound (B) having two phenolic hydroxy groups. In the formula (d-EP), X is a divalent group having a mesogenic skeleton, and the bifunctional phenolic compound (B) is at least one selected from chalcone compounds.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 completed based on the discovery that a cured product of a thermosetting resin composition having a specific formulation has high thermal conductivity.

[0009] According to the present invention, A bifunctional epoxy compound (A) having two epoxy groups represented by the formula (d-EP), a bifunctional phenol compound (B) having two phenolic hydroxyl groups; a thermally conductive filler; A thermosetting resin composition comprising:

[0010] [ka]

[0011] In formula (d-EP), X is Contains a group 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 thermosetting resin composition is provided, wherein the bifunctional phenol compound (B) is at least one selected from the compounds represented by formulas (b1) to (b5).

[0012] [ka]

[0013] Further, according to the present invention, A thermosetting resin composition used to form an encapsulant for encapsulating electronic components, comprising: The thermosetting resin composition comprises: A bifunctional epoxy compound (A) having two epoxy groups represented by the formula (d-EP), a bifunctional phenol compound (B) having two phenolic hydroxyl groups; Including, [ka] In formula (d-EP), X contains a group 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 thermosetting resin composition is provided, wherein the bifunctional phenol compound (B) is at least one selected from the compounds represented by formulas (b1) to (b5). [ka] Further, according to the present invention, A substrate; an electronic component provided on the substrate; a sealing material that seals the electronic component, The electronic device is provided, wherein the sealing material is made of a cured product of the thermosetting resin composition. [Effects of the Invention]

[0014] According to the present invention, there is provided a thermosetting resin composition having a cured product with high thermal conductivity, and a highly reliable electronic device including the cured product of the thermosetting resin composition as an encapsulant. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a 1H-NMR chart of 4,4'-dihydroxychalcone represented by formula (b1-1). [Figure 2] 1 is a 1H-NMR chart of 4,4'-dihydroxychalcone represented by formula (b1-1). [Figure 3] 1 is a 1H-NMR chart of 4,4'-dihydroxy-2,2'-dimethoxychalcone represented by formula (b3-1). [Figure 4] 1 is a 1H-NMR chart of 4,4'-dihydroxy-2,2'-dimethoxychalcone represented by formula (b3-1). [Figure 5] 1 is a 1H-NMR chart of dihydroxyterephthalchalcone represented by formula (b4-1). [Figure 6] 1 is a 1H-NMR chart of dihydroxyterephthalchalcone represented by formula (b4-1). DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present invention will be described. In this specification, unless otherwise specified, "to" indicates "or more" to "or less."

[0017] [Thermosetting resin composition] The thermosetting resin composition of this embodiment contains a bifunctional epoxy compound (A) having two epoxy groups and a bifunctional phenol compound (B) having two phenolic hydroxyl groups. When the thermosetting resin composition of this embodiment is heat-treated, the bifunctional epoxy compound (A) and the bifunctional phenol compound (B) undergo a curing reaction to produce a cured product containing a phenoxy resin. The components that can constitute the thermosetting resin composition of this embodiment are described below.

[0018] (Difunctional epoxy compound (A)) The difunctional epoxy compound (A) used in the thermosetting resin composition of this embodiment is a compound represented by formula (d-EP).

[0019] [ka]

[0020] X in the formula (d-EP) is a divalent group having a mesogenic skeleton. The thermosetting resin composition of the present embodiment contains the bifunctional epoxy compound (A) having a mesogenic skeleton, and the resulting cured product has high thermal conductivity and high heat resistance.

[0021] Examples of the mesogenic skeleton of the X group in formula (d-EP) include a biphenyl skeleton, a naphthalene skeleton, a phenylbenzoate skeleton, an azobenzene skeleton, a stilbene skeleton, a cyclohexylbenzene skeleton, and derivatives thereof. When the X group has the above-mentioned mesogenic skeleton, the cured product of the obtained thermosetting resin composition can have high thermal conductivity.

[0022] In one embodiment, at least one of the X groups in formula (d-EP) is a group represented by formula (2). By using a bifunctional epoxy compound (A) in which the X group in formula (d-EP) is a mesogenic skeleton represented by formula (2), the cured product of the thermosetting resin composition of this embodiment has high thermal conductivity and excellent heat resistance.

[0023] [ka]

[0024] In one embodiment, the bifunctional epoxy compound (A) is a compound represented by formula (2) in which R1, R4, R5, and R8 are alkyl groups having 1 to 4 carbon atoms, and R2, R3, R6, and R7 are hydrogen atoms. Among these, the bifunctional epoxy compound (A) is an epoxy compound represented by formula (2) in which R1, R4, R5, and R8 are alkyl groups having 1 carbon atom (methyl groups), and R2, R3, R6, and R7 are hydrogen atoms (the X group is a "tetramethylbiphenyl group"). By using such a bifunctional epoxy compound (A), the cured product of the obtained thermosetting resin composition can have an excellent balance between thermal conductivity and heat resistance.

[0025] In one embodiment, the bifunctional epoxy compound (A) is an epoxy compound in which R1, R4, R5, and R8 in formula (2) are alkyl groups each having one carbon atom, and R2, R3, R6, and R7 are hydrogen atoms (the X group is a biphenyl group). By using such a bifunctional epoxy compound (A), the cured product of the obtained thermosetting resin composition has excellent thermal conductivity and heat resistance.

[0026] In one embodiment, the bifunctional epoxy compound represented by formula (d-EP) is preferably a compound containing a tetramethylbiphenyl group and a biphenyl group as the group X. By containing such a combination of bifunctional epoxy compounds, the cured product of the obtained thermosetting resin composition can have an excellent balance between thermal conductivity and heat resistance.

[0027] (Bifunctional phenolic compound (B)) Examples of the bifunctional phenol compound (B) used in the thermosetting resin composition of this embodiment include compounds represented by the following formulas (b1) to (b5).

[0028] [ka]

[0029] (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.

[0030] 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.

[0031] (thermosetting resin) The thermosetting resin composition of this embodiment may contain a thermosetting resin as long as the effects of the present invention are not impaired. Examples of thermosetting resins include epoxy 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 may be any monomer, oligomer, or polymer having two or more reactive functional groups per molecule, and the molecular weight or molecular structure thereof is not particularly limited. These may be used alone or in combination of two or more.

[0032] (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.

[0033] (curing catalyst) The thermosetting resin composition may contain a curing catalyst as needed. The type and amount of the curing catalyst are not particularly limited, but an appropriate one can be selected from the viewpoints of reaction rate, reaction temperature, storage properties, and the like.

[0034] Examples of the curing catalyst 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.

[0035] (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.

[0036] 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.

[0037] [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.

[0038] 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.

[0039] [Uses of thermosetting resin compositions] The thermosetting resin composition of the present embodiment can be used as a sealing material for sealing electronic components.

[0040] 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]

[0041] EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these.

[0042] The raw materials used in the examples are as follows: (Difunctional epoxy compound) Epoxy compound 1: tetramethylbiphenyl-type epoxy resin represented by the following formula (3) (bifunctional epoxy compound, having a mesogen structure, manufactured by Mitsubishi Chemical Corporation, "YX4000")

[0043] [ka]

[0044] Epoxy compound 2: a 1:1 mixture of a tetramethylbiphenyl-type epoxy resin represented by the following formula (3) and a biphenyl-type epoxy resin represented by the following formula (4) ("YL-6121" manufactured by Mitsubishi Chemical Corporation)

[0045] [ka]

[0046] [ka]

[0047] (Bifunctional phenolic compounds) Phenolic compound 1: 4,4'-dihydroxychalcone represented by formula (b1-1)

[0048] [ka]

[0049] 4,4'-Dihydroxychalcone represented by formula (b1-1) was synthesized by the following procedure. 10 g (0.07 mol) of 4'-hydroxyacetophenone and 9 g (0.07 mol) of 4-hydroxybenzaldehyde were dissolved in 100 ml of ethanol. 5 ml of sulfuric acid (99%) was added to this mixed solution, and the mixture was reacted at 25°C for 12 hours. The resulting reaction mixture was purified by washing with pure water. 1H-NMR analysis confirmed that the resulting product had the structure of formula (b1-1). 1 The H-NMR chart is shown in Figure 2, and the peaks around 7.2-9.2 ppm are 1 The H-NMR chart is shown below.

[0050] Phenolic compound 2: 4,4'-dihydroxy-2,2'-dimethoxychalcone represented by formula (b3-1)

[0051] [ka]

[0052] 4,4'-Dihydroxy-2,2'-dimethoxychalcone represented by formula (b3-1) was synthesized by the following procedure. 5.5 g (0.03 mol) of 2'-methoxy-4'-hydroxyacetophenone and 5 g (0.03 mol) of 2-methoxy-4-hydroxybenzaldehyde were dissolved in 50 ml of ethanol. 3 ml of sulfuric acid (99%) was added to this mixed solution, and the mixture was reacted at 25°C for 12 hours. The resulting reaction mixture was purified by washing with pure water. 1 H-NMR analysis confirmed that the resulting product had the structure of formula (b3-1). 1 The H-NMR chart is shown in Figure 4, and the peaks around 6.8-7.8 ppm are 1 The H-NMR chart is shown below.

[0053] Phenolic compound 3: Dihydroxyterephthalchalcone represented by formula (b4-1)

[0054] [ka]

[0055] Dihydroxyterephthalchalcone represented by formula (b4-1) was synthesized by the following procedure. 10 g (0.07 mol) of 4'-hydroxyacetophenone and 5 g (0.03 mol) of terephthalaldehyde were dissolved in 100 ml of ethanol. 5 ml of sulfuric acid (99%) was added to this mixed solution, and the mixture was reacted at 25°C for 12 hours. The resulting reaction mixture was purified by washing with pure water. 1 H-NMR analysis confirmed that the resulting product had the structure of formula (b4-1). 1 The H-NMR chart is shown in Figure 6. 1 The H-NMR chart is shown below.

[0056] Phenolic compound 4: Novolac phenolic resin (Sumitomo Bakelite Co., Ltd., PR-55617)

[0057] (curing catalyst) Curing catalyst 1: 2-methyl-imidazole Curing catalyst 2: Triphenylphosphine (thermal conductive filler) Thermally conductive filler 1: Boron nitride

[0058] Examples 1 to 4 Resin compositions were prepared according to the formulations shown in Table 1. Example 5 Resin compositions containing thermally conductive fillers according to the formulations shown in Table 1 were prepared.

[0059] (Comparative Example 1) A resin composition was prepared using epoxy compound 1 and phenol compound 4. (Comparative Example 2) Resin compositions containing thermally conductive fillers according to the formulations shown in Table 1 were prepared. (Measurement of thermal conductivity) The thermal conductivity of the resin composition obtained above was measured by the following method. Preparation of resin molded body 1 A mixture of each of the epoxy resins of Examples 1 to 4 or Comparative Example 1, a phenolic resin, 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 1 (a sample for measuring thermal conductivity). Preparation of resin molded body 2 The thermosetting resin composition containing the thermally conductive filler of Example 5 or Comparative Example 2 was sandwiched between 0.018 mm copper foils and compression molded at 10 MPa, 180°C, and 90 minutes to obtain a resin molded product 2. A sample having a diameter of 10 mm for measuring thermal diffusivity was cut out from the obtained molded product and used for measuring thermal diffusivity.

[0060] Thermal conductivity measurement 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 body was calculated from the measured values ​​of thermal diffusion coefficient (α), specific heat (Cp), and density (Sp) according to the following formula. The results are shown in Table 1 below. Thermal conductivity [W / m K]=α[m 2 / s]×Cp[J / kg·K]×Sp[g / cm 3 ]

[0061] [Table 1]

[0062] The resin molded articles of Examples 1 to 4 had higher thermal conductivity than that of Comparative Example 1. The resin molded article of Example 5 containing the thermally conductive filler had higher thermal conductivity than that of Comparative Example 2.

Claims

1. A bifunctional epoxy compound (A) having two epoxy groups represented by formula (d-EP), a bifunctional phenol compound (B) having two phenolic hydroxyl groups; a thermally conductive filler; A thermosetting resin composition comprising: 【Chemistry 1】 In formula (d-EP), X contains a group represented by formula (2): 【Chemistry 2】 In formula (2), R 1 to R 8 each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, * represents a linking position, The thermosetting resin composition, wherein the bifunctional phenol compound (B) is at least one selected from the compounds represented by formulas (b1) to (b5): 【Transformation 3】

2. 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 The thermosetting resin composition according to claim 1 , wherein is a hydrogen atom.

3. 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 thermosetting resin composition according to claim 1 , wherein is a hydrogen atom.

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

5. The bifunctional epoxy compound represented by the formula (d-EP) is R １ , R ４ , R ５ , and R ８ is a methyl group, and R ２ , R ３ , R ６ , and R ７ a bifunctional epoxy compound represented by formula (2) in which R １ ~R ８ and a difunctional epoxy compound represented by formula (2):

6. The thermosetting resin composition according to claim 1 , further comprising a curing catalyst.

7. The thermosetting resin composition according to claim 1 , which is in the form of granules or tablets.

8. The thermosetting resin composition according to claim 1 , which is used to form an encapsulant for encapsulating electronic components.

9. A substrate; an electronic component provided on the substrate; a sealing material that seals the electronic component, The sealing material is made of a cured product of the thermosetting resin composition according to any one of claims 1 to 8. electronic equipment.

10. A thermosetting resin composition used to form an encapsulant for encapsulating electronic components, comprising: The thermosetting resin composition comprises: A bifunctional epoxy compound (A) having two epoxy groups represented by formula (d-EP), a bifunctional phenol compound (B) having two phenolic hydroxyl groups; Including, 【Chemistry 4】 In formula (d-EP), X contains a group represented by formula (2): 【Transformation 5】 In formula (2), R 1 to R 8 each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, * represents a linking position, The thermosetting resin composition, wherein the bifunctional phenol compound (B) is at least one selected from the compounds represented by formulas (b1) to (b5): 【Transformation 6】

11. 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 The thermosetting resin composition according to claim 10, wherein is a hydrogen atom.

12. 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 thermosetting resin composition according to claim 10, wherein is a hydrogen atom.

13. In the group represented by formula (2), R １ ~R ８ The thermosetting resin composition according to claim 10, wherein all of the following are hydrogen atoms.

14. The bifunctional epoxy compound represented by the formula (d-EP) is R １ , R ４ , R ５ , and R ８ is a methyl group, and R ２ , R ３ , R ６ , and R ７ a bifunctional epoxy compound represented by formula (2) in which R １ ~R ８ and a difunctional epoxy compound represented by formula (2): wherein all of

15. The thermosetting resin composition according to claim 10 , further comprising a curing catalyst.

16. The thermosetting resin composition according to claim 10 , further comprising a thermally conductive filler.

17. The thermosetting resin composition according to any one of claims 10 to 16, which is in the form of granules or tablets.

18. A substrate; an electronic component provided on the substrate; a sealing material that seals the electronic component, The sealing material is made of a cured product of the thermosetting resin composition according to any one of claims 10 to 17. electronic equipment.

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