TWI867037B - Resin composition - Google Patents

Abstract

The subject of the present invention is to provide a resin composition that can obtain a cured product that has excellent flexibility and excellent insulation reliability while keeping the tackiness low even when the inorganic filler is low in content. The solution of the present invention is a resin composition comprising (A) an epoxy resin, (B) an inorganic filler and (C) a polyimide resin, wherein the component (A) comprises (A-1) an epoxy resin containing a siloxane skeleton, and the content of the component (B) is 40% by mass or less when the non-volatile components in the resin composition are taken as 100% by mass.

Description

Resin composition

The present invention relates to a resin composition containing a polyimide resin, and further to a cured product, a resin sheet, a multi-layer flexible substrate, and a semiconductor device obtained by using the resin composition.

In recent years, there has been an increasing demand for thinner and lighter semiconductor components with higher mounting density. In order to meet this demand, attention is being paid to the use of flexible substrates as substrates used for semiconductor components. Flexible substrates can be made thinner and lighter than rigid substrates. Furthermore, since flexible substrates are soft and deformable, they can be bent and mounted.

Generally speaking, in the insulating material of the flexible substrate, although it is necessary to blend a soft resin such as a polyimide resin, when the polyimide resin is blended, the viscosity (adhesion) increases and the workability deteriorates. Although the viscosity can be suppressed by blending an inorganic filler (Patent Document 1), it becomes difficult to achieve both flexibility and a high blending rate of the inorganic filler. [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2014-95047

[Problems to be solved by the invention]

The subject of the present invention is to provide a resin composition that can obtain a cured product that has excellent flexibility and excellent insulation reliability while keeping the viscosity low even when the inorganic filler is low-doped. [Means for solving the subject]

As a result of diligent research to achieve the subject of the present invention, the inventors have found that by using a resin composition comprising (A) an epoxy resin, (B) an inorganic filler and (C) a polyimide resin, wherein the (A) component is a resin composition comprising (A-1) an epoxy resin containing a siloxane skeleton, a cured product can be obtained which has excellent flexibility and excellent insulation reliability while keeping the content of the (B) inorganic filler at 40% by mass or less, even when the content is low, thereby completing the present invention.

That is, the present invention includes the following contents. [1] A resin composition comprising (A) an epoxy resin, (B) an inorganic filler and (C) a polyimide resin, wherein the component (A) comprises (A-1) an epoxy resin containing a siloxane skeleton, and the content of the component (B) is 40% by mass or less when the non-volatile components in the resin composition are taken as 100% by mass. [2] A resin composition as described in [1] above, wherein the component (A-1) is an epoxy resin containing a siloxane skeleton. [3] A resin composition as described in [1] or [2] above, wherein the component (A-1) is a compound represented by formula (A1),

[In the formula, ^R1 is independently an alkylene oxide group; ^R2 is independently a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted aryl group; ^R3 and ^R4 are independently a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted aryl group, or ^R3 and ^R4 are taken together to show one -O- and are bonded to each other to form a cyclosiloxane skeleton; s is an integer greater than 1]. [4] The resin composition as described in any one of [1] to [3] above, wherein the molecular weight of component (A-1) is 800 or less. [5] The resin composition as described in any one of [1] to [4] above, wherein the epoxy equivalent of component (A-1) is 150 g/eq. to 250 g/eq. [6] The resin composition as described in any one of the above [1] to [5], wherein the content of component (A-1) is 5% by mass or more, based on 100% by mass of the non-volatile components in the resin composition. [7] The resin composition as described in any one of the above [1] to [6], wherein the content of component (A-1) is 10% by mass or less, based on 100% by mass of the non-volatile components in the resin composition. [8] The resin composition as described in any one of the above [1] to [7], wherein the average particle size of component (B) is 1 μm or less. [9] The resin composition as described in any one of the above [1] to [8], wherein component (B) is silicon dioxide. [10] The resin composition as described in any one of the above [1] to [9], wherein the weight average molecular weight of component (C) is 1,000 or more and 100,000 or less. [11] The resin composition as described in any one of the above [1] to [10], wherein the content of component (C) is 20% by mass or more, based on 100% by mass of the non-volatile components in the resin composition. [12] The resin composition as described in any one of the above [1] to [11], wherein the content of component (C) is 30% by mass or less, based on 100% by mass of the non-volatile components in the resin composition. [13] The resin composition as described in any one of the above [1] to [12], further comprising (D) a hardener. [14] A resin composition as described in [13] above, wherein the component (D) comprises an active ester curing agent. [15] A resin composition as described in any one of [1] to [14] above, which is used to form an insulating layer of a multi-layer flexible substrate. [16] A cured product of the resin composition as described in any one of [1] to [15] above. [17] A resin sheet comprising a support and a resin composition layer formed by the resin composition as described in any one of [1] to [15] above and disposed on the support. [18] A multi-layer flexible substrate, comprising an insulating layer formed by curing a resin composition as described in any one of [1] to [15] above. [19] A semiconductor device, comprising the multi-layer flexible substrate as described in [18] above. [Effects of the invention]

According to the resin composition of the present invention, a cured product can be obtained which has low viscosity even when the inorganic filler is low in content and has excellent flexibility and excellent insulation reliability.

The present invention is described in detail below with respect to its suitable embodiments. However, the present invention is not limited to the following embodiments and examples, and can be arbitrarily modified and implemented without departing from the scope of the patent application of the present invention and its equivalent scope.

<Resin composition> The resin composition of the present invention is a resin composition comprising (A) epoxy resin, (B) inorganic filler material and (C) polyimide resin, wherein the component (A) comprises (A-1) epoxy resin containing a siloxane skeleton, and the content of the component (B) is 40% by mass or less. By using such a resin composition, a cured product can be obtained which has excellent flexibility and excellent insulation reliability even when the inorganic filler material is low in content.

The resin composition of the present invention may further include any component in addition to (A) epoxy resin, (B) inorganic filler and (C) polyimide resin. Examples of the arbitrary component include (D) hardener, (E) hardening accelerator, (F) other additives and (G) organic solvent. The following is a detailed description of each component included in the resin composition.

<(A) Epoxy resin> The resin composition of the present invention includes (A) epoxy resin. The so-called (A) epoxy resin refers to a hardening resin having an epoxy group. (A) Epoxy resin also includes a modified epoxy resin.

The content of the epoxy resin (A) in the resin composition is not particularly limited, but when the non-volatile components in the resin composition are taken as 100% by mass, it is preferably 10% by mass or more, more preferably 20% by mass or more, further preferably 25% by mass or more, and particularly preferably 30% by mass or more. The upper limit of the content of the epoxy resin (A) in the resin composition is not particularly limited, but when the non-volatile components in the resin composition are taken as 100% by mass, it is preferably 70% by mass or less, more preferably 60% by mass or less, further preferably 50% by mass or less, and particularly preferably 40% by mass or less.

<(A-1) Epoxy resin containing a siloxane skeleton> (A) Epoxy resin includes (A-1) Epoxy resin containing a siloxane skeleton. The so-called (A-1) Epoxy resin containing a siloxane skeleton refers to a compound having two or more epoxy groups and a siloxane (Si-O-Si) bond.

(A-1) The epoxy resin containing a siloxane skeleton may be an epoxy resin containing an epoxy siloxane skeleton or an epoxy resin containing a chain siloxane skeleton, but is preferably an epoxy resin containing an epoxy siloxane skeleton.

The number of silicon atoms forming the siloxane bonds of the (A-1) siloxane skeleton-containing epoxy resin is not particularly limited, but is preferably 3 or more, more preferably 10 or less, more preferably 8 or less, further preferably 6 or less, and further preferably 5 or less in one molecule. It is particularly preferably 4.

The number of epoxy groups in the siloxane skeleton-containing epoxy resin (A-1) is not particularly limited, but is preferably 3 or more, more preferably 10 or less, more preferably 8 or less, further preferably 6 or less, and further preferably 5 or less, and particularly preferably 4 per molecule.

All the substitutable positions of the silicon atoms in the epoxy resin (A-1) having a siloxane skeleton are preferably substituted with a hydrocarbon group such as an alkyl group, an alkenyl group, an aryl group, etc. which may or may not have an epoxy group. The hydrocarbon group may have a substituent other than an epoxy group.

(A-1) an epoxy resin containing a siloxane skeleton, preferably a compound represented by formula (A1),

[In the formula, ^R1 independently represents an alkylene oxide group; ^R2 independently represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted aryl group; ^R3 and ^R4 independently represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted aryl group, or ^R3 and ^R4 together show one -O- and are bonded to each other to form a cyclosiloxane skeleton; s represents an integer greater than 1].

The so-called "alkyl" refers to a straight chain, branched chain and/or cyclic monovalent aliphatic saturated hydrocarbon group. "Alkyl" is preferably an alkyl group having 1 to 10 carbon atoms. Examples of "alkyl" include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, sec-pentyl, tert-pentyl, cyclopentyl, cyclohexyl, cyclopentylmethyl, 2-cyclohexylmethyl, 2-cyclopentylethyl, 2-cyclohexylethyl, and the like.

The so-called "epoxyalkyl group" refers to a group in which two hydrogen atoms bonded to different carbon atoms of an alkyl group are replaced by one oxygen atom to form an oxygen heterocyclopropane (ethylene oxide) ring. "Epoxyalkyl group" is preferably an epoxyalkyl group having 2 to 10 carbon atoms. Examples of "epoxyalkyl group" include straight-chain epoxyalkyl groups such as 2,3-epoxypropyl, 3,4-epoxybutyl, 4,5-epoxypentyl, and 5,6-epoxyhexyl; branched-chain epoxyalkyl groups such as 2,3-epoxy-2-methylpropyl, 3,4-epoxy-3-methylbutyl; 2,3-epoxy Cyclooxyalkyl groups such as cyclopentyl, 3,4-cyclopentyl, 2,3-cyclohexyl, and 3,4-cyclohexyl; 2,3-cyclopentylmethyl, 3,4-cyclopentylmethyl, 2,3-cyclohexylmethyl, 3,4-cyclohexylmethyl, 2-(2,3-cyclohexyl) The straight-chain alkyl groups having a cyclic epoxyalkyl group at the terminal such as 4-(2,3-epoxycyclopentyl)butyl, 4-(3,4-epoxycyclopentyl)butyl, 4-(2,3-epoxycyclohexyl)butyl and 4-(3,4-epoxycyclohexyl)butyl and the like.

The so-called "alkenyl" refers to a straight chain, branched chain and/or cyclic monovalent aliphatic unsaturated hydrocarbon group having at least one carbon-carbon double bond. The "alkenyl" is preferably an alkenyl group having 2 to 10 carbon atoms. Examples of the "alkenyl" include vinyl, 1-propenyl, 2-propenyl, 2-methyl-1-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 3-methyl-2-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 4-methyl-3-pentenyl, 1-hexenyl, 3-hexenyl, 5-hexenyl, and 2-cyclohexenyl.

Although not particularly limited, examples of the substituents of the alkyl group in the "substituted or unsubstituted alkyl group" and the alkenyl group in the "substituted or unsubstituted alkenyl group" include halogen atoms, cyano groups, nitro groups, alkyl-oxy groups, alkyl-carbonyl groups, alkyl-oxy-carbonyl groups, alkyl-carbonyl-oxy groups, alkenyl-oxy groups, alkenyl-carbonyl groups, alkenyl-oxy-carbonyl groups, alkenyl-carbonyl-oxy groups, aryl groups, aryl-oxy groups, aryl-carbonyl groups, aryl-oxy-carbonyl groups, aryl-carbonyl-oxy groups, and combinations thereof. The number of substituents is preferably 1 to 3, more preferably 1.

The term "aryl" refers to a monovalent aromatic hydrocarbon group. Preferably, the "aryl" is an aryl group having 6 to 14 carbon atoms. Examples of the "aryl" include phenyl, 1-naphthyl, and 2-naphthyl.

Although not particularly limited, examples of the substituent of the aryl group in the "substituted or unsubstituted aryl group" include a halogen atom, a cyano group, a nitro group, an alkyl group, an alkyl-oxy group, an alkyl-carbonyl group, an alkyl-oxy-carbonyl group, an alkyl-carbonyl-oxy group, an alkenyl group, an alkenyl-oxy group, an alkenyl-carbonyl group, an alkenyl-oxy-carbonyl group, an alkenyl-carbonyl-oxy group, an aryl group, an aryl-alkyl group, an aryl-alkenyl group, an aryl-oxy group, an aryl-carbonyl group, an aryl-oxy-carbonyl group, an aryl-carbonyl-oxy group, and the like, or a combination thereof. The number of the substituents is preferably 1 to 3, and more preferably 1.

Examples of the "halogen atom" include a fluorine atom, a chlorine atom, and a bromine atom.

In formula (A1), ^R1 independently represents an alkylene oxide group, preferably a linear alkyl group having an alkylene oxide group at the terminal, more preferably a methyl group having an alkylene oxide group, or an ethyl group having an alkylene oxide group at the terminal, and particularly preferably a 2-(3,4-epoxycyclohexyl)ethyl group.

In formula (A1), ^R2 independently represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted aryl group, preferably a substituted or unsubstituted alkyl group, more preferably an (unsubstituted) alkyl group, still more preferably a methyl group, an ethyl group, a propyl group or an isopropyl group, and particularly preferably a methyl group.

In formula (A1), ^R3 and ^R4 are independently substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, or substituted or unsubstituted aryl, or ^R3 and ^R4 are combined to show one -O- and bond to each other to form a cyclosiloxane skeleton. Preferably, ^R3 and ^R4 are combined to show one -O- and bond to each other to form a cyclosiloxane skeleton.

In formula (A1), s represents an integer greater than or equal to 1, and preferably an integer greater than or equal to 2. s is preferably an integer less than or equal to 9, more preferably an integer less than or equal to 7, still more preferably an integer less than or equal to 5, and still more preferably an integer less than or equal to 4. It is particularly preferred that s is 3.

Specific examples of the epoxy resin (A-1) containing a siloxane skeleton include epoxy resins containing a chain siloxane skeleton such as 1,3,5-tris(2-(3,4-epoxycyclohexyl)ethyl)-1,1,3,5,5-pentamethyltrisiloxane; 2,4,6,8-tetra(4-(3,4-epoxycyclopentyl)butyl)-2,4,6,8-tetramethylcyclotetrasiloxane; 2,4,6,8-tetra(3-(3,4-epoxycyclopentyl)propyl)-2,4,6,8-tetramethylcyclotetrasiloxane; Preferably, the epoxy resin has a cyclosiloxane skeleton, such as 2,4,6,8-tetrakis(2-(3,4-epoxycyclohexyl)ethyl)-2,4,6,8-tetramethylcyclotetrasiloxane and 2,4,6,8,10-penta(2-(3,4-epoxycyclohexyl)ethyl)-2,4,6,8,10-pentamethylcyclopentasiloxane. Among them, 2,4,6,8-tetrakis(2-(3,4-epoxycyclohexyl)ethyl)-2,4,6,8-tetramethylcyclotetrasiloxane is particularly preferred.

Examples of commercially available products of the siloxane skeleton-containing epoxy resin (A-1) include "KR-470" (main component: 2,4,6,8-tetrakis(2-(3,4-epoxycyclohexyl)ethyl)-2,4,6,8-tetramethylcyclotetrasiloxane) and "X-40-2667" (main component: 1,3,5-tris(2-(3,4-epoxycyclohexyl)ethyl)-1,1,3,5,5-pentamethyltrisiloxane) manufactured by Shin-Etsu Chemical Co., Ltd.

The molecular weight of the siloxane skeleton-containing epoxy resin (A-1) is preferably 2,000 or less, more preferably 1,500 or less, further preferably 1,000 or less, and particularly preferably 800 or less. The lower limit can be set to, for example, 200 or more, 400 or more, 600 or more, etc.

The epoxy equivalent of the siloxane skeleton-containing epoxy resin (A-1) is preferably 1,000 g/eq. or less, more preferably 500 g/eq. or less, further preferably 300 g/eq. or less, and particularly preferably 250 g/eq. or less. The lower limit is preferably 50 g/eq. or more, more preferably 100 g/eq. or more, further preferably 130 g/eq. or more, and particularly preferably 150 g/eq. or more.

(A-1) The viscosity (25°C) of the epoxy resin containing a siloxane skeleton is preferably 100 mPa･s to 10,000 mPa･s, more preferably 1,000 mPa･s to 5,000 mPa･s.

The content of the epoxy resin having a siloxane skeleton (A-1) in the resin composition is not particularly limited, but is preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 4% by mass or more, and particularly preferably 5% by mass or more, based on 100% by mass of the nonvolatile components in the resin composition. The upper limit of the content of the epoxy resin having a siloxane skeleton (A-1) in the resin composition is not particularly limited, but is preferably 30% by mass or less, more preferably 20% by mass or less, further preferably 15% by mass or less, and particularly preferably 10% by mass or less, based on 100% by mass of the nonvolatile components in the resin composition.

<Optional epoxy resins other than component (A-1)> (A) Epoxy resin may further include other optional epoxy resins in addition to (A-1) epoxy resin containing a siloxane skeleton.

Examples of the optional epoxy resin other than the component (A-1) include bixylenol epoxy resins, bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, bisphenol AF epoxy resins, dicyclopentadiene epoxy resins, trisphenol epoxy resins, naphthol novolac epoxy resins, phenol novolac epoxy resins, tert-butyl-ophthalic acid epoxy resins, naphthalene epoxy resins, naphthol epoxy resins, anthracene epoxy resins, epoxy resins. Propylamine type epoxy resin, epoxypropyl ester type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, epoxy resin with butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spirocyclic epoxy resin, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, naphthyl ether type epoxy resin, trihydroxymethyl type epoxy resin, tetraphenylethane type epoxy resin, isocyanurate type epoxy resin, epoxypropylcyclohexane type epoxy resin, etc. Any epoxy resin may be used alone or in combination of two or more.

The resin composition preferably contains an epoxy resin having two or more epoxy groups in one molecule as any epoxy resin other than component (A-1). The proportion of the epoxy resin having two or more epoxy groups in one molecule relative to 100% by mass of the nonvolatile component of the epoxy resin other than component (A-1) is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more.

Epoxy resins include epoxy resins that are liquid at 20°C (hereinafter, sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at 20°C (hereinafter, sometimes referred to as "solid epoxy resins"). The resin composition of the present invention may contain only liquid epoxy resins or only solid epoxy resins as any epoxy resin other than component (A-1), but preferably contains a combination of liquid epoxy resins and solid epoxy resins.

The liquid epoxy resin is preferably a liquid epoxy resin having two or more epoxy groups in one molecule.

As the liquid epoxy resin, preferred are bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, phenol novolac type epoxy resin, aliphatic epoxy resin having an ester skeleton, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, and epoxy resin having a butadiene structure.

Specific examples of liquid epoxy resins include "HP4032", "HP4032D", and "HP4032SS" (naphthalene-based epoxy resins) manufactured by DIC Corporation; "828US", "828EL", "jER828EL", "825", and "EPIKOTE" manufactured by Mitsubishi Chemical Corporation; "828EL" (bisphenol A type epoxy resin); "jER807" and "1750" (bisphenol F type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER152" (phenol novolac type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "630", "630LSD" and "604" (epoxypropylamine type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "ED-523T" (glycyrol type epoxy resin) manufactured by ADEKA Corporation; "EP-3950L" and "EP-3980S" (epoxypropylamine type epoxy resin) manufactured by ADEKA Corporation; "EP-4088S" (dicyclopentadiene type epoxy resin) manufactured by ADEKA Corporation Epoxy resin); "ZX1059" manufactured by Nippon Steel & Sumitomo Chemicals (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin); "EX-721" manufactured by Nagase ChemteX (epoxypropyl ester type epoxy resin); "Celloxide2021P" manufactured by Daicel (alicyclic epoxy resin with an ester skeleton); "PB-3600" manufactured by Daicel, "JP-100" and "JP-200" manufactured by Nippon Soda (epoxy resins with a butadiene structure); "ZX1658" and "ZX1658GS" manufactured by Nippon Steel & Sumitomo Chemicals (cyclohexane type epoxy resins), etc. These can be used alone or in combination of two or more types.

The solid epoxy resin is preferably a solid epoxy resin having three or more epoxy groups in one molecule, and more preferably an aromatic solid epoxy resin having three or more epoxy groups in one molecule.

As the solid epoxy resin, preferred are bixylenol type epoxy resin, naphthalene type epoxy resin, naphthalene type tetrafunctional epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol type epoxy resin, biphenyl type epoxy resin, naphthyl ether type epoxy resin, anthracene type epoxy resin, bisphenol A type epoxy resin, bisphenol AF type epoxy resin, and tetraphenylethane type epoxy resin.

Specific examples of solid epoxy resins include "HP4032H" (naphthalene-based epoxy resin) manufactured by DIC Corporation; "HP-4700" and "HP-4710" (naphthalene-based tetrafunctional epoxy resin) manufactured by DIC Corporation; "N-690" (cresol-phenol-based epoxy resin) manufactured by DIC Corporation; "N-695" (cresol-phenol-based epoxy resin) manufactured by DIC Corporation; "HP-7200", "HP-7200HH", and "HP-7200H" (dicyclopentadiene-based epoxy resin) manufactured by DIC Corporation; and "EXA-731 1", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthyl ether type epoxy resin); "EPPN-502H" (trisphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol phenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC3000H", "NC3000", "NC3000L", "NC3000FH", "NC3100" (biphenyl type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; Nippon Steel Chemical "ESN475V" manufactured by Nippon Steel Chemical & Materials Co., Ltd. (naphthalene type epoxy resin); "ESN485" manufactured by Nippon Steel Chemical & Materials Co., Ltd. (naphthol type epoxy resin); "ESN375" manufactured by Nippon Steel Chemical & Materials Co., Ltd. (dihydroxynaphthalene type epoxy resin); "YX4000H", "YX4000", "YX4000HK", "YL7890" manufactured by Mitsubishi Chemical Corporation (bixylenol type epoxy resin); "YL6121" manufactured by Mitsubishi Chemical Corporation (biphenyl type epoxy resin); "YX8800" manufactured by Mitsubishi Chemical Corporation (anthracene type epoxy resin); "YX7 "700" (a phenolic epoxy resin containing a xylene structure); "PG-100" and "CG-500" manufactured by Osaka Gas Chemical Co., Ltd.; "YL7760" manufactured by Mitsubishi Chemical Corporation (a bisphenol AF epoxy resin); "YL7800" manufactured by Mitsubishi Chemical Corporation (a fluorene epoxy resin); "jER1010" manufactured by Mitsubishi Chemical Corporation (a solid bisphenol A epoxy resin); "jER1031S" manufactured by Mitsubishi Chemical Corporation (a tetraphenylethane epoxy resin), etc. These can be used alone or in combination of two or more.

When a liquid epoxy resin and a solid epoxy resin are used in combination as any epoxy resin other than component (A-1), the mass ratio of the liquid epoxy resin to the solid epoxy resin is preferably in the range of 100:1 to 1:100, more preferably in the range of 10:1 to 1:40, and even more preferably in the range of 1:1 to 1:20.

The epoxy equivalent of any epoxy resin other than component (A-1) is preferably 50 g/eq. to 5,000 g/eq., more preferably 60 g/eq. to 2,000 g/eq., still more preferably 70 g/eq. to 1,000 g/eq., and still more preferably 80 g/eq. to 500 g/eq. The epoxy equivalent is the mass of the resin per 1 equivalent of epoxy group. The epoxy equivalent can be measured in accordance with JIS K7236.

The weight average molecular weight (Mw) of any epoxy resin other than component (A-1) is preferably 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500. The weight average molecular weight of the resin can be measured as a value converted to polystyrene by gel permeation chromatography (GPC).

When the resin composition contains any epoxy resin other than the component (A-1), the content of the any epoxy resin other than the component (A-1) in the resin composition is not particularly limited, but is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, and particularly preferably 20% by mass or more, based on 100% by mass of the non-volatile components in the resin composition. The upper limit of the content of any epoxy resin other than the component (A-1) in the resin composition is not particularly limited, but is preferably 60 mass % or less, more preferably 50 mass % or less, further preferably 40 mass % or less, and particularly preferably 30 mass % or less, based on 100 mass % of the nonvolatile components in the resin composition.

When the resin composition contains any epoxy resin other than the component (A-1), the content of the epoxy resin having a siloxane skeleton (A-1) in the epoxy resin (A) is not particularly limited, but is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, and particularly preferably 20% by mass or more, based on the total amount of the epoxy resin (A) as 100% by mass. The upper limit of the content of the (A-1) siloxane skeleton-containing epoxy resin in the (A) epoxy resin is not particularly limited, but is preferably 50% by mass or less, more preferably 40% by mass or less, further preferably 30% by mass or less, and particularly preferably 25% by mass or less, based on the total amount of the (A) epoxy resin being 100% by mass.

<(B) Inorganic filler> The resin composition of the present invention contains (B) inorganic filler. (B) Inorganic filler is contained in the resin composition in the form of particles.

As the material of the (B) inorganic filler, an inorganic compound is used. Examples of the material of the (B) inorganic filler include silicon dioxide, aluminum oxide, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silicon dioxide is particularly suitable. Examples of silicon dioxide include amorphous silicon dioxide, fused silicon dioxide, crystalline silicon dioxide, synthetic silicon dioxide, and hollow silicon dioxide. Moreover, spherical silicon dioxide is preferred as silicon dioxide. (B) The inorganic filler may be used alone or in combination of two or more at any ratio.

Examples of commercially available inorganic fillers (B) include "SP60-05" and "SP507-05" manufactured by Nippon Steel & Sumitomo Metal Materials Co., Ltd.; "YC100C", "YA050C", "YA050C-MJE", and "YA010C" manufactured by Admatechs; "SYLFIL NSS-3N", "SYLFIL NSS-4N", and "SYLFIL NSS-5N" manufactured by Tokuyama; "SC2500SQ", "SO-C4", "SO-C2", and "SO-C1" manufactured by Admatechs; and "UFP-30", "DAW-03", and "FB-105FD" manufactured by Electrochemical Corporation.

(B) The average particle size of the inorganic filler is not particularly limited, but is preferably 40 μm or less, more preferably 10 μm or less, further preferably 5 μm or less, further more preferably 3 μm or less, and particularly preferably 1 μm or less. (B) The lower limit of the average particle size of the inorganic filler is not particularly limited, but is preferably 0.005 μm or more, more preferably 0.01 μm or more, further more preferably 0.05 μm or more, further more preferably 0.1 μm or more, further more preferably 0.2 μm or more, and particularly preferably 0.3 μm or more. (B) The average particle size of the inorganic filler can be measured by a laser diffraction/scattering method based on the Mie scattering theory. Specifically, the particle size distribution of the inorganic filler can be made on a volume basis by using a laser diffraction scattering particle size distribution measuring device, and the median diameter can be set as the average particle size for measurement. The measurement sample can be made by weighing 100 mg of the inorganic filler and 10 g of methyl ethyl ketone in a vial and dispersing them with ultrasound for 10 minutes. The sample is measured using a laser diffraction particle size distribution measuring device, and the wavelength of the light source used is set to blue and red. The volume-based particle size distribution of the inorganic filler is measured by a flow cell method, and the average particle size can be calculated from the obtained particle size distribution as the median diameter. As an example of a laser diffraction particle size distribution measuring device, the "LA-960" manufactured by Horiba, Ltd. can be listed.

(B) The specific surface area of the inorganic filler is not particularly limited, but is preferably 0.1 ^{m 2} /g or more, more preferably 0.5 m ² /g or more, further preferably 1 m ² /g or more, and particularly preferably 5 m ² /g or more. (B) The upper limit of the specific surface area of the inorganic filler is not particularly limited, but is preferably 50 m ² /g or less, more preferably 30 m ² /g or less, further preferably 20 m ² /g or less, and particularly preferably 15 m ² /g or less. The specific surface area of the inorganic filler is obtained by adsorbing nitrogen gas on the sample surface using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech) according to the BET method, and calculating the specific surface area using the BET multipoint method.

The (B) inorganic filler material is preferably surface treated with an appropriate surface treatment agent. The surface treatment can improve the moisture resistance and dispersibility of the (B) inorganic filler material. Examples of the surface treatment agent include vinyl trimethoxysilane, vinyl triethoxysilane and other vinyl-based silane coupling agents; epoxy-based silane coupling agents such as 2-(3,4-epoxyhexyl)ethyl trimethoxysilane, 3-glycidoxypropyl methyl dimethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl methyl diethoxysilane, 3-glycidoxypropyl triethoxysilane and the like; styrene-based silane coupling agents such as p-styrene trimethoxysilane; 3-methacryloyloxypropyl methyl dimethoxysilane, 3-methacryloyloxypropyl Methacrylic silane coupling agents such as acyloxypropyl trimethoxysilane, 3-methacrylic acyloxypropyl methyl diethoxy silane, 3-methacrylic acyloxypropyl triethoxy silane, etc.; acryl silane coupling agents such as 3-acrylic acyloxypropyl trimethoxy silane, N-2-(aminoethyl)-3-aminopropyl methyl dimethoxy silane, N-2-(aminoethyl)-3-aminopropyl trimethoxy silane, 3-aminopropyl trimethoxy silane, 3-aminopropyl triethoxy silane, 3-triethoxysilyl-N-(1,3-dimethyl-butylene) propylamine , N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-8-aminooctyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane and the like amino-based silane coupling agents; isocyanurate-based silane coupling agents such as tris-(trimethoxysilylpropyl)isocyanurate; urea-based silane coupling agents such as 3-ureidopropyltrialkoxysilane; 3-butylpropylmethyldimethoxysilane, 3-butylpropyltrimethoxysilane and the like butyl-based silane coupling agents; isocyanate-based silane coupling agents such as 3-isocyanatepropyltriethoxysilane and the like silane coupling agents; anhydride-based silane coupling agents such as 3-trimethoxysilylpropyl succinic anhydride; silane coupling agents such as methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, 1,6-bis(trimethoxysilyl)hexane, trifluoropropyltrimethoxysilane, and other non-silane coupling-alkoxysilane compounds. Among them, amino-based silane coupling agents are preferred. The surface treatment agent may be used alone or in combination of two or more in any ratio.

Examples of commercially available surface treatment agents include "KBM-1003", "KBE-1003" (vinyl silane coupling agents); "KBM-303", "KBM-402", "KBM-403", "KBE-402", "KBE-403" (epoxy silane coupling agents); "KBM-1403" (styrene silane coupling agent ... M-502", "KBM-503", "KBE-502", "KBE-503" (methacrylic silane coupling agent); "KBM-5103" (acrylic silane coupling agent); "KBM-602", "KBM-603", "KBM-903", "KBE-903", "KBE-9103P", "KBM-573", "KBM-575" ( Amine silane coupling agent); "KBM-9659" (isocyanurate silane coupling agent); "KBE-585" (urea silane coupling agent); "KBM-802", "KBM-803" (heptyl silane coupling agent); "KBE-9007N" (isocyanate silane coupling agent); "X-12-967C" (anhydride silane coupling agent); "KBM-13", "KBM-22 "KBM-103", "KBE-13", "KBE-22", "KBE-103", "KBM-3033", "KBE-3033", "KBM-3063", "KBE-3063", "KBE-3083", "KBM-3103C", "KBM-3066", "KBM-7103" (non-silane coupling-alkoxysilane compounds), etc.

The degree of surface treatment by the surface treatment agent is preferably within a specified range from the viewpoint of improving the dispersibility of the inorganic filler. Specifically, it is preferred that 100% by mass of the inorganic filler is surface treated with 0.2% by mass to 5% by mass of the surface treatment agent, more preferably 0.2% by mass to 3% by mass, and even more preferably 0.3% by mass to 2% by mass.

The degree of surface treatment by the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler. From the perspective of improving the dispersibility of the inorganic filler, the amount of carbon per unit surface area of the inorganic filler is preferably 0.02 mg/ ^m2 or more, more preferably 0.1 mg/ ^m2 or more, and even more preferably 0.2 mg/ ^m2 or more. On the other hand, from the perspective of preventing the increase in the melt viscosity of the resin composition or the melt viscosity in the sheet form, it is preferably 1.0 mg/ ^m2 or less, more preferably 0.8 mg/m2 or ^less , and even more preferably 0.5 mg/m2 or ^less .

(B) The amount of carbon per unit surface area of the inorganic filler can be measured by washing the surface-treated inorganic filler with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, as a solvent, a sufficient amount of MEK is added to the inorganic filler surface-treated with a surface treatment agent, and then ultrasonically washed at 25°C for 5 minutes. After removing the supernatant and drying the solid components, a carbon analyzer can be used to measure the amount of carbon per unit surface area of the inorganic filler. As a carbon analyzer, the "EMIA-320V" manufactured by Horiba, Ltd. can be used.

The content of the (B) inorganic filler in the resin composition is 40% by mass or less, preferably 38% by mass or less, more preferably 36% by mass or less, still more preferably 34% by mass or less, and particularly preferably 32% by mass or less, based on the non-volatile components in the resin composition being 100% by mass. The lower limit of the content of the (B) inorganic filler in the resin composition is not particularly limited, but is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, and particularly preferably 30% by mass or more, based on the non-volatile components in the resin composition being 100% by mass.

<(C) Polyimide resin> The resin composition of the present invention includes (C) polyimide resin. (C) Polyimide resin is a resin having an imide bond in a repeating unit. (C) Polyimide resin generally includes (1) a resin obtained by an imidization reaction of a diamine compound and tetracarboxylic anhydride, or (2) a resin obtained by an imidization reaction of a diisocyanate compound and tetracarboxylic anhydride. (C) Polyimide resin also includes modified polyimide resins such as siloxane-modified polyimide resins.

(C) The polyimide resin is not particularly limited, but may include, for example, a structure represented by formula (C1),

[In the formula, ^X1 represents a tetravalent group obtained by removing two -CO-O-CO- from tetracarboxylic dianhydride, and may be, for example, an organic group comprising two or more (e.g., 2 to 3,000, 2 to 1,000, 2 to 100, or 2 to 50) backbone atoms selected from carbon atoms, oxygen atoms, nitrogen atoms, and sulfur atoms. ^X2 represents a divalent group obtained by removing two _-NH2 from a diamine compound, or a divalent group obtained by removing two -NCO from a diisocyanate compound, and may be, for example, an organic group comprising two or more (e.g., 2 to 3,000, 2 to 1,000, 2 to 100, or 2 to 50) backbone atoms selected from carbon atoms, oxygen atoms, nitrogen atoms, and sulfur atoms. n represents an integer greater than 2]. The organic groups of ^X1 and ^X2 in formula (C1) are not particularly limited as long as they are chemically stable structures, and are structures that can be appropriately selected by those skilled in the art, such as structures of known polyimide resins. (C) When the polyimide resin contains the structure represented by formula (C1), it preferably contains 60% by mass or more of the structure represented by formula (C1), more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

The diamine compound used for preparing the polyimide resin (C) is not particularly limited, but examples thereof include aliphatic diamine compounds and aromatic diamine compounds.

Examples of the aliphatic diamine compound include linear aliphatic diamine compounds such as 1,2-ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-hexamethylenediamine, 1,5-diaminopentane, and 1,10-diaminodecane; 1,2-diamino-2-methylpropane, Branched chain aliphatic diamine compounds such as 2,3-diamino-2,3-butane and 2-methyl-1,5-diaminopentane; alicyclic diamine compounds such as 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine); dimer acid type diamine (hereinafter also referred to as "dimer diamine"), etc.

The so-called dimer acid type diamine refers to a diamine compound obtained by replacing the two terminal carboxyl groups (-COOH) of the dimer acid with aminomethyl (-CH ₂ -NH ₂ ) or amino (-NH ₂ ). Dimer acid is a compound obtained by dimerizing unsaturated fatty acids (preferably those with 11 to 22 carbon atoms, particularly preferably those with 18 carbon atoms), and its industrial production process is almost standardized in the industry. Dimer acid can be easily obtained, and the main component is a dimer acid with 36 carbon atoms obtained by dimerizing unsaturated fatty acids with 18 carbon atoms such as oleic acid and linoleic acid, which are particularly cheap and easily available. In addition, dimer acid may contain any amount of monomeric acid, trimer acid, other polymerized fatty acids, etc. depending on the production method, the degree of purification, etc. In addition, although double bonds remain after the polymerization reaction of unsaturated fatty acids, in this specification, hydrogen additions that further undergo hydrogen addition reaction to reduce the unsaturation are also included in dimer acids. Dimer acid-type diamines are commercially available, for example, "PRIAMINE 1073", "PRIAMINE 1074", "PRIAMINE 1075" manufactured by Croda Japan, "VERSAMINE 551", "VERSAMINE 552" manufactured by Cognis Japan, etc.

Examples of the aromatic diamine compounds include phenylenediamine compounds such as 1,4-phenylenediamine, 1,2-phenylenediamine, 1,3-phenylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,5-diaminobiphenyl, and 2,4,5,6-tetrafluoro-1,3-phenylenediamine; naphthalene diamine compounds such as 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, 2,6-diaminonaphthalene, and 2,3-diaminonaphthalene; 4,4'-diamino-2, 2'-Bis(trifluoromethyl)-1,1'-biphenyl, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, 4-aminophenyl 4-aminobenzoate, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 2,2-bis(4-aminophenyl)propane, 4,4'-(hexafluoro isopropylidene) diphenylamine, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, α,α-bis[4-(4-aminophenoxy)phenyl]-1,3-diisopropylbenzene, α,α-bis[4-(4-aminophenoxy)phenyl]-1,4-diisopropylbenzene, 4,4'-(9-fluorenylidene) diphenylamine, 2,2-bis(3-methyl-4-aminophenyl)propane diphenylamine compounds such as 2,2-bis(3-methyl-4-aminophenyl)benzene, 4,4'-diamino-3,3'-dimethyl-1,1'-biphenyl, 4,4'-diamino-2,2'-dimethyl-1,1'-biphenyl, 9,9'-bis(3-methyl-4-aminophenyl)fluorene, 5-(4-aminophenoxy)-3-[4-(4-aminophenoxy)phenyl]-1,1,3-trimethyldihydroindane, and 4-aminobenzoic acid 5-amino-1,1'-biphenyl-2-yl.

As the diamine compound, a commercially available one may be used, or one synthesized by a known method may be used. The diamine compound may be used alone or in combination of two or more.

The diisocyanate compound used for preparing the polyimide resin (C) is not particularly limited, but examples thereof include aliphatic diisocyanate compounds, aromatic diisocyanate compounds, and polyurethane having isocyanate groups at both ends.

Examples of the aliphatic diisocyanate compound include linear aliphatic diisocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, and dodecamethylene diisocyanate; branched aliphatic diisocyanate compounds such as 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and 2,2-dimethylpentamethylene diisocyanate; isophorone diisocyanate (IPDI), 1,4-cyclohexyl diisocyanate (CDI); alicyclic diisocyanate compounds such as 1,4-diisocyanate, 2-diisocyanate, 1,3-diisocyanate, 4-methyl-1,3-cyclohexyl diisocyanate, 2-methyl-1,4-cyclohexyl diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 3a,4,5,6,7,7a-hexahydro-4,7-methanol dihydroindene (methanoindan)-1,8-ylene diisocyanate, etc.; dimer acid type diisocyanate, etc.

The so-called dimer acid type diisocyanate refers to a diisocyanate compound obtained by replacing the amino group (-NH ₂ ) of the dimer acid type diamine described above with an isocyanate group (-NCO).

Examples of the aromatic diisocyanate compound include phenylene diisocyanate compounds such as 1,4-phenylene diisocyanate, 1,3-phenylene diisocyanate, tolylene-2,6-diisocyanate, tolylene-2,4-diisocyanate, tolylene-3,5-diisocyanate, naphthalene diisocyanate compounds such as 1,3-naphthalene diisocyanate, 1,6-naphthalene diisocyanate, 1,7-naphthalene diisocyanate, 1,8-naphthalene diisocyanate, 2,6-naphthalene diisocyanate, 2,7-naphthalene diisocyanate, and diisocyanatobenzene compounds such as 4,4'-diphenylmethane diisocyanate and 4,4'-diphenylether diisocyanate.

The polyurethane having isocyanate groups at both ends may be obtained by subjecting aliphatic diisocyanate compounds and/or aromatic diisocyanate compounds listed above to urethanization reaction with a polymer having hydroxyl groups at both ends. Examples of the polymer having hydroxyl groups at both ends include polybutadiene having hydroxyl groups at both ends, hydrogenated polybutadiene having hydroxyl groups at both ends, polyisoprene having hydroxyl groups at both ends, and hydrogenated polyisoprene having hydroxyl groups at both ends; and polyether having hydroxyl groups at both ends, such as polyethylene glycol having hydroxyl groups at both ends, polypropylene glycol having hydroxyl groups at both ends, and polytetramethylene glycol having hydroxyl groups at both ends.

The number average molecular weight of the polymer having hydroxyl groups at both ends is not particularly limited, but is preferably 500 or more, more preferably 1,000 or more, and even more preferably 2,000 or more. The upper limit of the number average molecular weight of the polymer having hydroxyl groups at both ends is not particularly limited, but is preferably 10,000 or less, and more preferably 8,000 or less. The number average molecular weight here is a value measured by gel permeation chromatography (GPC) method (polystyrene conversion).

The polyurethane containing isocyanate groups at both ends is, for example, a polyurethane containing isocyanate groups at both ends represented by formula (C2),

[In the formula, ^X2a each independently represents a divalent group obtained by removing two -NCO from an aliphatic diisocyanate compound or an aromatic diisocyanate compound, and may be, for example, an organic group having 2 to 50 backbone atoms selected from carbon atoms, oxygen atoms, nitrogen atoms, and sulfur atoms. ^X2b each independently represents a divalent group obtained by removing two -OH from a polymer having hydroxyl groups at both ends, and may be, for example, an organic group having 2 or more backbone atoms (e.g., 2 to 1,000, 2 to 500) selected from carbon atoms and oxygen atoms. m represents an integer of 1 to 10].

As the diisocyanate compound, a commercially available one may be used, or one synthesized by a known method or a method in accordance therewith may be used. The diisocyanate compound may be used alone or in combination of two or more.

The tetracarboxylic anhydride used for preparing the (C) polyimide resin is not particularly limited, and examples thereof include aliphatic tetracarboxylic dianhydride and aromatic tetracarboxylic dianhydride.

Specific examples of the aliphatic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, 3,3',4,4'-bicyclohexyltetracarboxylic dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene tetracarboxylic dianhydride, -4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,2-ethylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, thio-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, and the like.

Examples of the aromatic tetracarboxylic dianhydride include benzenetetracarboxylic dianhydride such as pyromellitic dianhydride and 1,2,3,4-benzenetetracarboxylic dianhydride; naphthalenetetracarboxylic dianhydride such as 1,4,5,8-naphthalenetetracarboxylic dianhydride and 2,3,6,7-naphthalenetetracarboxylic dianhydride; anthracenetetracarboxylic dianhydride such as 2,3,6,7-anthracenetetracarboxylic dianhydride; 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-diphenylethertetracarboxylic dianhydride, 3,3',4,4'-diphenyl 2,3,3',4'-diphenyl tetracarboxylic dianhydride, 2,2',3,3'-biphenyl tetracarboxylic dianhydride, 2,3,3',4'-biphenyl tetracarboxylic dianhydride, 2,3,3',4'-benzophenone tetracarboxylic dianhydride, 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, 2,3,3',4'-diphenyl sulfonate tetracarboxylic dianhydride, 2,2'-bis(3,4-dicarboxyphenoxyphenyl)sulfonate dianhydride, methylene-4,4'-diphthalic acid Acid dianhydride, 1,1-ethynylene (ethynylidene)-4,4'-diphthalic acid dianhydride, 2,2-propylene-4,4'-diphthalic acid dianhydride, 1,2-ethylene-4,4'-diphthalic acid dianhydride, 1,3-trimethylene-4,4'-diphthalic acid dianhydride, 1,4-tetramethylene-4,4'-diphthalic acid dianhydride, 1,5-pentamethylene-4,4'-diphthalic acid dianhydride, 1,3-bis(2-(1-(di-)-phthalic acid)-4,4'-diphthalic acid dianhydride, diphthalic acid dianhydride such as (3,4-dicarboxyphenyl)phthalic anhydride, 1,4-bis(3,4-dicarboxyphenyl)phthalic anhydride, 1,3-bis(3,4-dicarboxyphenoxy)phthalic anhydride, 1,4-bis(3,4-dicarboxyphenoxy)phthalic anhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 4,4'-(4,4'-isopropylidene diphenoxy)bisphthalic acid dianhydride, and the like.

As tetracarboxylic dianhydride, commercially available products may be used, or products synthesized by a known method or a method in accordance therewith may be used. Tetracarboxylic dianhydride may be used alone or in combination of two or more.

The content of the structure derived from the aromatic tetracarboxylic dianhydride relative to the entire structure derived from the tetracarboxylic dianhydride constituting the polyimide resin (C) is preferably 10 mol % or more, more preferably 30 mol % or more, even more preferably 50 mol % or more, more preferably 70 mol % or more, more preferably 90 mol % or more, and particularly preferably 100 mol %.

The weight average molecular weight of the polyimide resin (C) is not particularly limited, but is preferably 1,000 or more, more preferably 3,000 or more, further preferably 5,000 or more, and particularly preferably 7,000 or more. The upper limit of the weight average molecular weight of the polyimide resin (C) is not particularly limited, but is preferably 100,000 or less, more preferably 80,000 or less, particularly preferably 60,000 or less, and particularly preferably 50,000 or less.

The number average molecular weight of the polyimide resin (C) is not particularly limited, but is preferably 1,000 or more, more preferably 3,000 or more, even more preferably 5,000 or more, and particularly preferably 7,000 or more. The upper limit of the number average molecular weight of the polyimide resin (C) is not particularly limited, but is preferably 100,000 or less, more preferably 80,000 or less, particularly preferably 60,000 or less, and even more preferably 50,000 or less.

The content of the polyimide resin (C) in the resin composition is not particularly limited, but when the non-volatile components in the resin composition are taken as 100% by mass, it is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, and particularly preferably 20% by mass or more. The upper limit of the content of the polyimide resin (C) in the resin composition is not particularly limited, but when the non-volatile components in the resin composition are taken as 100% by mass, it is preferably 50% by mass or less, more preferably 40% by mass or less, further preferably 35% by mass or less, and particularly preferably 30% by mass or less.

<(D) Hardener> The resin composition of the present invention may further include (D) hardener. (D) Hardener has the function of hardening (A) epoxy resin.

Although not particularly limited, examples of the (D) hardener include phenol hardeners, naphthol hardeners, acid anhydride hardeners, active ester hardeners, benzoxazine hardeners, cyanate ester hardeners, and carbodiimide hardeners. The hardeners may be used alone or in combination of two or more. The (D) hardener preferably includes a hardener selected from the group consisting of phenol hardeners, naphthol hardeners, and active ester hardeners, and particularly preferably includes an active ester hardener.

As the phenolic hardener and the naphthol hardener, from the viewpoint of heat resistance and water resistance, a phenolic hardener having a phenolic structure or a naphthol hardener having a phenolic structure is preferred. Furthermore, from the viewpoint of adhesion to the object, a nitrogen-containing phenolic hardener or a nitrogen-containing naphthol hardener is preferred, and a phenolic hardener containing a triazine skeleton or a naphthol hardener containing a triazine skeleton is more preferred. Among them, from the viewpoint of highly satisfying heat resistance, water resistance and adhesion, a phenolic novolac resin containing a triazine skeleton is preferred. Specific examples of the phenol-based hardener and the naphthol-based hardener include "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Wa Kasei Co., Ltd., "NHN", "CBN", and "GPH" manufactured by Nippon Kayaku Co., Ltd., "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-495", "SN-375", and "SN-395" manufactured by Nippon Steel Chemical & Materials Co., Ltd., and "LA-7052", "LA-7054", "LA-3018", "LA-3018-50P", "LA-1356", "TD2090", and "TD-2090-60M" manufactured by DIC Corporation.

Examples of the acid anhydride curing agent include those having one or more acid anhydride groups in one molecule, and preferably those having two or more acid anhydride groups in one molecule. Specific examples of the acid anhydride curing agent include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, Trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenylsulfonatetetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, ethylene glycol bis(anhydro trimellitic acid), styrene-maleic acid resin copolymerized with maleic acid, etc. Polymer type acid anhydrides, etc. Commercially available products of acid anhydride-based hardeners include "HNA-100" and "MH-700" manufactured by Shin Nippon Rika Co., Ltd.

As the active ester curing agent, there is no particular limitation, but generally speaking, it is preferred to use a compound having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxylamine esters, and esters of heterocyclic hydroxyl compounds. The active ester curing agent is preferably obtained by a condensation reaction of a carboxylic acid compound and/or a thiocarboxylic acid compound with a hydroxyl compound and/or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester curing agent obtained from a carboxylic acid compound and a hydroxyl compound is preferred, and an active ester curing agent obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound is more preferred. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of the phenol compound or naphthol compound include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, o-cresol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phenoxytriol (Phloroglucin), benzenetriol, dicyclopentadiene-type diphenol compounds, and phenol novolac. Here, the so-called "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing two molecules of phenol with one molecule of dicyclopentadiene.

Specifically, preferred are active ester compounds containing a dicyclopentadiene diphenol structure, active ester compounds containing a naphthalene structure, active ester compounds containing acetylated phenolic novolacs, and active ester compounds containing benzoylated phenolic novolacs. Among them, more preferred are active ester compounds containing a naphthalene structure and active ester compounds containing a dicyclopentadiene diphenol structure. The so-called "dicyclopentadiene diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

Commercially available active ester curing agents include, for example, active ester compounds containing a dicyclopentadiene-type diphenol structure, "EXB9451", "EXB9460", "EXB9460S", "HPC-8000", "HPC-8000H", "HPC-8000-65T", "HPC-8000H-65TM", "EXB-8000L", "EXB-8000L-65M", and "EXB-8000L-65TM" (manufactured by DIC Corporation); active ester compounds containing a naphthalene structure, Examples include "EXB-9416-70BK", "EXB-8150-65T", "EXB-8100L-65T", and "EXB-8150L-65T" (manufactured by DIC Corporation); as active ester hardeners of acetylated phenol novolacs, "DC808" (manufactured by Mitsubishi Chemical Corporation) can be cited; as active ester hardeners of benzoylated phenol novolacs, "YLH1026" (manufactured by Mitsubishi Chemical Corporation), "YLH1030" (manufactured by Mitsubishi Chemical Corporation), and "YLH1048" (manufactured by Mitsubishi Chemical Corporation) can be cited, etc.

Specific examples of benzoxazine-based hardeners include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemicals, "HFB2006M" manufactured by Showa High Polymer, and "P-d" and "F-a" manufactured by Shikoku Chemical Industries.

Examples of cyanate ester curing agents include those derived from bisphenol A dicyanate, polyphenol cyanate (oligo(3-methylene-1,5-phenylene cyanate)), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylenediphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanate)phenylpropane, Bifunctional cyanate resins such as bis(4-cyanate-phenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl)sulfide, and bis(4-cyanatephenyl)ether, polyfunctional cyanate resins such as phenol novolac and cresol novolac, and prepolymers of these cyanate resins partially triazine-treated. Specific examples of cyanate ester curing agents include "PT30" and "PT60" manufactured by Lonza Japan (both are phenol novolac-type polyfunctional cyanate resins), "BA230", and "BA230S75" (prepolymers of bisphenol A dicyanate partially or entirely triazine-treated trimers), etc.

Specific examples of carbodiimide-based hardeners include "V-03" and "V-07" manufactured by Nisshinbo Chemical Co., Ltd.

When the resin composition includes (D) a hardener, the amount ratio of (A) an epoxy resin to (D) a hardener is preferably 1:0.2 to 1:2, more preferably 1:0.3 to 1:1.5, and even more preferably 1:0.4 to 1:1.4 in terms of [number of epoxy groups of (A) an epoxy resin]: [number of reactive groups of (D) a hardener]. Here, the reactive group of the (D) hardener is, for example, an aromatic hydroxyl group in the case of a phenolic hardener or a naphthol hardener, and is an active ester group in the case of an active ester hardener, depending on the type of the hardener.

(D) The reactive group equivalent weight of the curing agent is preferably 50 g/eq. to 3,000 g/eq., more preferably 100 g/eq. to 1,000 g/eq., still more preferably 100 g/eq. to 500 g/eq., and particularly preferably 100 g/eq. to 300 g/eq. The reactive group equivalent weight is the mass of the reactive group per 1 equivalent of the curing agent.

When the (D) hardener includes an active ester hardener, the content thereof is not particularly limited, but is preferably 10% by mass or more, more preferably 20% by mass or more, further preferably 30% by mass or more, and particularly preferably 40% by mass or more, based on the total amount of the (D) hardener being 100% by mass.

When the resin composition contains the (D) hardener, the content of the (D) hardener in the resin composition is not particularly limited, but is preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 4% by mass or more, and particularly preferably 5% by mass or more, based on 100% by mass of the nonvolatile components in the resin composition. The upper limit of the content of the (D) hardener in the resin composition is not particularly limited, but is preferably 20% by mass or less, more preferably 15% by mass or less, further preferably 10% by mass or less, and particularly preferably 8% by mass or less, based on 100% by mass of the nonvolatile components in the resin composition.

<(E) Hardening accelerator> The resin composition of the present invention may contain (E) a hardening accelerator as an optional component. (E) The hardening accelerator has the function of accelerating the hardening of (A) the epoxy resin.

(E) The curing accelerator is not particularly limited, but examples thereof include phosphorus-based curing accelerators, urea-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, and metal-based curing accelerators. Among them, phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, and metal-based curing accelerators are preferred, and imidazole-based curing accelerators are particularly preferred. The curing accelerator may be used alone or in combination of two or more.

Phosphorus-based hardening accelerators include, for example, aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium)pyromellitic acid, tetrabutylphosphonium hexahydrophthalate, tetrabutylphosphonium cresol phenolic trimer salt, and di-tert-butylmethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetraphenylborate, Aromatic phosphonium salts such as p-tolyl borate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; aromatic phosphine-quinone addition reactants such as triphenylphosphine-p-benzoquinone addition reactants; tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methylphenyl)phosphine aliphatic phosphines such as tricyclohexyl phosphine, dibutylphenyl phosphine, di-tert-butylphenyl phosphine, methyldiphenyl phosphine, ethyldiphenyl phosphine, butyldiphenyl phosphine, diphenylcyclohexyl phosphine, triphenylphosphine, tri-o-tolyl phosphine, tri-m-tolyl phosphine, tri-p-tolyl phosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,5-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine, tris( Aromatic phosphines such as tris(2,3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, and 2,2'-bis(diphenylphosphino)diphenyl ether.

Examples of urea-based hardening accelerators include 1,1-dimethylurea; aliphatic dimethylureas such as 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, and 3-cyclooctyl-1,1-dimethylurea; 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(2-methylphenyl)-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, 3-(3,4-dimethylphenyl)-1,1 -dimethylurea, 3-(4-isopropylphenyl)-1,1-dimethylurea, 3-(4-methoxyphenyl)-1,1-dimethylurea, 3-(4-nitrophenyl)-1,1-dimethylurea, 3-[4-(4-methoxyphenoxy)phenyl]-1,1-dimethylurea, 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea, 3-[3-(trifluoromethyl)phenyl]-1,1-dimethylurea, N,N-(1,4-phenylene)bis(N’,N’-dimethylurea), N,N-(4-methyl-1,3-phenylene)bis(N’,N’-dimethylurea) [toluenebisdimethylurea] and the like.

Examples of the amine-based hardening accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine (DMAP), benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclic (5,4,0)-undecene, etc., preferably 4-dimethylaminopyridine.

Examples of the imidazole-based hardening accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazole trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]- Ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazolyl Imidazole compounds such as oxadiazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazolium, 2-phenylimidazolium, and adducts of imidazole compounds with epoxy resins.

As the imidazole-based hardening accelerator, a commercially available product can be used, for example, "P200-H50" manufactured by Mitsubishi Chemical Corporation can be mentioned.

Examples of the guanidine-based hardening accelerator include cyanamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanidine, 1-ethylbiguanidine, 1-n-butylbiguanidine, 1-n-octadecylbiguanidine, 1,1-dimethylbiguanidine, 1,1-diethylbiguanidine, 1-cyclohexylbiguanidine, 1-allylbiguanidine, 1-phenylbiguanidine, and 1-(o-tolyl)biguanidine.

Examples of metal hardening accelerators include organic metal complexes or organic metal salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organic metal complexes include organic cobalt complexes such as cobalt (II) acetylacetate and cobalt (III) acetylacetate, organic copper complexes such as copper (II) acetylacetate, organic zinc complexes such as zinc (II) acetylacetate, organic iron complexes such as iron (III) acetylacetate, organic nickel complexes such as nickel (II) acetylacetate, and organic manganese complexes such as manganese (II) acetylacetate. Examples of the organic metal salt include zinc octylate, tin octylate, zinc cycloalkanoate, cobalt cycloalkanoate, tin stearate, zinc stearate, and the like.

When the resin composition contains (E) a hardening accelerator, the content of the (E) hardening accelerator in the resin composition is not particularly limited, but when the non-volatile components in the resin composition are taken as 100% by mass, it is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, further preferably 0.05% by mass or more, and particularly preferably 0.1% by mass or more. The upper limit of the content of the (E) hardening accelerator in the resin composition is not particularly limited, but when the non-volatile components in the resin composition are taken as 100% by mass, it is preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 1% by mass or less, and particularly preferably 0.5% by mass or less.

<(F) Other additives> The resin composition of the present invention may further contain any additive as a non-volatile component. Examples of such additives include organic fillers such as rubber particles, polyamide microparticles, and polysilicone particles; thermoplastic resins such as phenoxy resins, polyvinyl acetal resins, polyolefin resins, polysulfide resins, polyethersulfide resins, polyphenylene ether resins, polycarbonate resins, polyetheretherketone resins, and polyester resins; and organic copper compounds, organic zinc compounds, and organic cobalt compounds. Organic metal compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, carbon black, etc.; polymerization inhibitors such as hydroquinone, o-catechol, o-pyrogallol, phenothiazine, etc.; leveling agents such as polysilicone leveling agents and acryl polymer leveling agents; tackifiers such as Bentonite and montmorillonite; polysilicone defoaming agents, acryl polymer leveling agents, etc. Defoaming agents, fluorine-based defoaming agents, vinyl resin-based defoaming agents; UV absorbers such as benzotriazole-based UV absorbers; adhesion enhancers such as urea silane; adhesion enhancers such as triazole-based adhesion enhancers, tetrazole-based adhesion enhancers, triazine-based adhesion enhancers; antioxidants such as hindered phenol-based antioxidants, hindered amine-based antioxidants; Stilbene (Stilbene) (e.g., phosphoric acid ester compounds, phosphazene compounds, hypophosphorous acid compounds, red phosphorus), nitrogen flame retardants (e.g., melamine), halogen flame retardants, inorganic flame retardants (e.g., antimony trioxide), etc. The additives may be used alone or in combination of two or more at any ratio. (F) The content of other additives may be appropriately set if it is a person with common knowledge in the field of the present invention.

<(G) Organic solvent> The resin composition of the present invention may contain any organic solvent as a volatile component in addition to the non-volatile component mentioned above. As the (G) organic solvent, a known organic solvent may be used appropriately, and its type is not particularly limited. Examples of the (G) organic solvent include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, and diphenyl ether; alcohol solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, methoxypropionic acid methyl ester; esters, etc.; ester alcohol solvents, such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents, such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents, such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents, such as dimethyl sulfoxide; nitrile solvents, such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents, such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; aromatic hydrocarbon solvents, such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. (G) The organic solvent may be used alone or in combination of two or more at any ratio.

<Manufacturing method of resin composition> The resin composition of the present invention can be manufactured by, for example, adding (A) epoxy resin, (B) inorganic filler, (C) polyimide resin (preliminarily imidized), (D) hardener if necessary, (E) hardening accelerator if necessary, (F) other additives if necessary, and (G) organic solvent if necessary, in any reaction container in any order and/or partly or all at the same time and mixing. In addition, in the process of adding and mixing the components, the temperature can be appropriately set, and heating and/or cooling can be performed temporarily or from the beginning to the end. In addition, in the process of adding and mixing the components, stirring or shaking can be performed. During or after the addition and mixing, the resin composition may be stirred using a stirring device such as a mixer to uniformly disperse the resin composition.

<Characteristics of the resin composition> The resin composition of the present invention comprises (A) an epoxy resin, (B) an inorganic filler and (C) a polyimide resin, and the component (A) comprises (A-1) an epoxy resin containing a siloxane skeleton. Therefore, when the content of the inorganic filler (B) is 40% by mass or less, the viscosity can be suppressed to a low level even when the content is low, and a resin composition having excellent flexibility and excellent insulation reliability can be obtained.

The cured product of the resin composition of the present invention has excellent flexibility. For example, as shown in the following Test Example 1, a layered cured product of the resin composition having a thickness of 40 μm, a width of 15 mm, and a length of 110 mm was subjected to an MIT folding test in accordance with JIS C-5016 at a load of 2.5 N, a bending angle of 90 degrees, a bending speed of 175 times/minute, and a bending radius of 1.0 mm. The number of folding times was preferably 3,000 times or more, more preferably 5,000 times or more, even more preferably 7,000 times or more, and particularly preferably 8,000 times or more.

The cured product of the resin composition of the present invention has excellent insulation reliability. For example, the insulation resistance value of the insulation layer of the evaluation substrate measured by the method of Test Example 3 below is preferably 1.00×10 ⁷ Ω or more, more preferably 1.00×10 ⁸ Ω or more, even more preferably 1.00×10 ⁹ Ω or more, and particularly preferably 1.00×10 ¹⁰ Ω or more.

The resin composition of the present invention can suppress the viscosity to a low level. For example, in the following Test Example 2, the adhesion measured under the conditions of a glass probe with a diameter of 5 mm, a load of 1 kgf/cm ² , a contact speed of 0.5 mm/sec, a tensile speed of 0.5 mm/sec, a holding time of 10 seconds, and a temperature of 80°C is preferably 1.8 N or less, more preferably 1.6 N or less, still more preferably 1.4 N or less, and particularly preferably 1.2 N or less.

<Application of resin composition> The resin composition of the present invention can be used in a wide range of applications such as insulating materials, solder resists, bottom filling materials, die bonding materials, semiconductor sealing materials, cavity filling resins, and component embedding resins for printed wiring boards, multi-layer flexible substrates, etc. Printed wiring boards, multi-layer flexible substrates, etc. can be manufactured using sheet-like laminate materials such as resin sheets and prepregs.

<Resin sheet> The resin sheet of the present invention comprises a support and a resin composition layer formed by the resin composition of the present invention disposed on the support.

The thickness of the resin composition layer is preferably 200 μm or less, more preferably 150 μm or less, further preferably 100 μm or less, and particularly preferably 70 μm or less. The lower limit of the thickness of the resin composition layer is not particularly limited, but is usually 1 μm or more, 1.5 μm or more, 2 μm or more, etc.

Examples of the support include films made of plastic materials, metal foils, and release papers, and films made of plastic materials and metal foils are preferred.

When a film made of a plastic material is used as a support, examples of the plastic material include polyesters such as polyethylene terephthalate (hereinafter sometimes referred to as "PET") and polyethylene naphthalate (hereinafter sometimes referred to as "PEN"), polycarbonate (hereinafter sometimes referred to as "PC"), acryl such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, etc. Among them, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

When a metal foil is used as a support, examples of the metal foil include copper foil and aluminum foil, and copper foil is preferred. The copper foil may be a foil made of a single metal including copper, or may be a foil made of an alloy including copper and other metals (such as tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.).

The support may be subjected to matte treatment, corona treatment, and anti-static treatment on the surface that is bonded to the resin composition layer.

In addition, as the support, a support with a release layer having a release layer on the surface bonded to the resin composition layer can be used. As a release agent for the release layer of the support with a release layer, for example, at least one release agent selected from the group consisting of alkyd resins, polyolefin resins, urethane resins and silicone resins can be listed. The support with a release layer can be a commercially available product, for example, a PET film having a release layer with an alkyd resin-based release agent as a main component, namely "SK-1", "AL-5", "AL-7" manufactured by Lintec, "Lumirror T60" manufactured by Toray, "Purex" manufactured by Teijin, "Unipiel" manufactured by Unitika, etc.

The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, more preferably in the range of 10 μm to 60 μm. In addition, when a support with a release layer is used, the thickness of the entire support with a release layer is preferably in the above range.

In one embodiment, the resin sheet may further include other layers if necessary. Examples of such other layers include a protective film provided on the surface of the resin composition layer that is not bonded to the support (i.e., the surface opposite to the support) and the like. The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating the protective film, the adhesion or scratching of dust and the like on the surface of the resin composition layer can be suppressed.

The resin sheet can be produced by directly preparing a resin composition or a resin varnish prepared by dissolving the resin composition in an organic solvent, applying the resin varnish on a support using a die coater or the like, and then drying the varnish to form a resin composition layer.

Examples of the organic solvent that can be used when coating on the support include the same ones as those listed in the description of the organic solvent as a component of the resin composition. The organic solvent may be used alone or in combination of two or more.

Drying can be carried out by known methods such as heating and hot air blowing. Although the drying conditions are not particularly limited, the drying is carried out in such a manner that the content of the organic solvent in the resin composition layer becomes 10 mass % or less, preferably 5 mass % or less. Although it varies depending on the boiling point of the organic solvent in the resin composition or resin varnish, for example, when a resin composition or resin varnish containing 30 mass % to 60 mass % of an organic solvent is used, the resin composition layer can be formed by drying at 50°C to 150°C for 3 minutes to 10 minutes.

The resin sheet can be stored in a roll. If the resin sheet has a protective film, it can be used by peeling off the protective film.

<Laminated sheet> Laminated sheet is a sheet produced by laminating and curing a plurality of resin composition layers. Laminated sheet is a sheet containing a plurality of insulating layers as a cured product of the resin composition layer. Usually, the number of resin composition layers laminated to produce a laminated sheet is the same as the number of insulating layers contained in the laminated sheet. The specific number of insulating layers per laminated sheet is usually 2 or more, preferably 3 or more, particularly preferably 5 or more, preferably 20 or less, more preferably 15 or less, and particularly preferably 10 or less.

The laminated sheet may be a sheet bent so that the surfaces of one side thereof face each other. The minimum bending radius of the laminated sheet is not particularly limited, but is preferably 0.1 mm or more, more preferably 0.2 mm or more, and even more preferably 0.3 mm or more, preferably 5 mm or less, more preferably 4 mm or less, and particularly preferably 3 mm or less.

Holes may be formed in each insulating layer included in the laminate sheet. The holes may be used as through holes or through-holes in the multi-layer flexible substrate.

The laminate sheet may further include an arbitrary element in addition to the insulating layer. For example, the laminate sheet may include a conductive layer as an arbitrary element. The conductive layer is usually formed partially on the surface of the insulating layer or between the insulating layers. This conductive layer is usually used as wiring in a multi-layer flexible substrate.

The conductive material used for the conductive layer is not particularly limited. In a suitable embodiment, the conductive layer includes one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin and indium. The conductive material may be a single metal or an alloy. As the alloy, for example, an alloy of two or more metals selected from the above group (e.g., nickel-chromium alloy, copper-nickel alloy and copper-titanium alloy) can be listed. Among them, from the viewpoint of versatility, cost, and ease of patterning in forming the conductive layer, single metals such as chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, and alloys such as nickel-chromium alloys, copper-nickel alloys, and copper-titanium alloys are preferred. Among them, single metals such as chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, and nickel-chromium alloys are more preferred; and single metals such as copper are even more preferred.

The conductive layer may be a single layer structure or a composite structure, wherein the composite structure includes two or more single metal layers or alloy layers including different types of metals or alloys. When the conductive layer is a composite structure, the layer in contact with the insulating layer is preferably a single metal layer of chromium, zinc or titanium or an alloy layer of nickel-chromium alloy.

The conductive layer may be patterned in order to be used as wiring.

The thickness of the conductive layer varies depending on the design of the multi-layer flexible substrate, but is preferably 3 μm to 35 μm, more preferably 5 μm to 30 μm, further preferably 10 μm to 20 μm, and particularly preferably 15 μm to 20 μm.

The thickness of the laminated sheet is preferably 100 μm or more, more preferably 150 μm or more, particularly preferably 200 μm or more, and is preferably 2,000 μm or less, more preferably 1,000 μm or less, and particularly preferably 500 μm or less.

<Method for producing laminated sheet> The laminated sheet can be produced by a production method comprising (a) preparing a resin sheet, and (b) using the resin sheet, laminating and curing a plurality of resin composition layers. The order of laminating and curing the resin composition layers is arbitrary as long as the desired laminated sheet can be obtained. Depending on the components contained in the resin composition, for example, after laminating all the plurality of resin composition layers, the laminated plurality of resin composition layers can be cured at one time. In addition, for example, the laminated resin composition layers can be cured to the extent that other resin composition layers are laminated on a certain resin composition layer.

A preferred embodiment of step (b) is described below. In the embodiments described below, for the purpose of distinction, the resin composition layers are appropriately numbered, such as "first resin composition layer" and "second resin composition layer", and further, the insulating layers obtained by hardening the resin composition layers are also numbered the same as the resin composition layers, such as "first insulating layer" and "second insulating layer".

In a preferred embodiment, step (b) includes: (II) hardening the first resin composition layer to form a first insulating layer, and (VI) laminating the second resin composition layer on the first insulating layer, and (VII) hardening the second resin composition layer to form a second insulating layer. Furthermore, step (b) may include, if necessary: (I) a step of laminating a first resin composition layer on a thin sheet support substrate, (III) a step of drilling holes in the first insulating layer, (IV) a step of roughening the first insulating layer, (V) a step of forming a conductor layer on the first insulating layer, and the like. Each step is described below.

Step (I) is a step of laminating a first resin composition layer on a thin sheet support substrate before step (II). The thin sheet support substrate is a removable member, for example, a plate, sheet or film-shaped member.

The lamination of the sheet support substrate and the first resin composition layer can be performed by vacuum lamination. In the vacuum lamination, the heating and pressing temperature is preferably in the range of 60°C to 160°C, more preferably in the range of 80°C to 140°C, the heating and pressing pressure is preferably in the range of 0.098MPa to 1.77MPa, more preferably in the range of 0.29MPa to 1.47MPa, and the heating and pressing time is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds. The lamination is preferably performed under reduced pressure conditions with a pressure of less than 26.7hPa.

Lamination can be performed by a commercially available vacuum laminating machine. Examples of commercially available vacuum laminating machines include a vacuum press laminating machine manufactured by Nobuki Seisakusho Co., Ltd., a vacuum applicator manufactured by Nikko Materials Co., Ltd., and a batch vacuum press laminating machine.

When a resin sheet is used, the sheet support substrate and the first resin component layer can be laminated, for example, by pressing the resin sheet from the support body side to heat and press the first resin component layer of the resin sheet onto the sheet support substrate. As a member for heat and press the resin sheet onto the sheet support substrate (hereinafter, it may be appropriately referred to as a "heat and press member"), for example, a heated metal plate (SUS mirror plate, etc.) or a metal roller (SUS roller) can be listed. Preferably, the heated pressing member is not directly pressed onto the resin sheet, but is pressed onto the surface of the sheet supporting substrate through an elastic material such as heat-resistant rubber in such a manner that the first resin component layer fully follows the surface irregularities.

After lamination, the first resin component layer can be smoothed by pressing under normal pressure (atmospheric pressure), for example, with a heated pressing member. For example, when a resin sheet is used, the first resin component layer of the resin sheet can be smoothed by pressing the resin sheet with a heated pressing member from the support side. The pressing conditions for the smoothing treatment can be set to the same conditions as the heated pressing conditions for the above-mentioned lamination. The smoothing treatment can be performed by a commercially available laminating press. The lamination and smoothing treatment can be performed continuously using the above-mentioned commercially available vacuum laminating press.

Step (II) is a step of curing the first resin composition layer to form a first insulating layer. The curing conditions of the first resin composition layer are not particularly limited, and any conditions used when forming an insulating layer of a printed wiring board can be applied. The first resin composition layer can be cured, for example, by thermal curing.

Generally, the specific heat curing conditions vary depending on the type of resin composition. For example, the curing temperature is preferably 120°C to 240°C, more preferably 150°C to 220°C, and even more preferably 170°C to 210°C. Moreover, the curing time is preferably 5 minutes to 120 minutes, more preferably 10 minutes to 110 minutes, and even more preferably 20 minutes to 100 minutes.

Before the first resin composition layer is heat-hardened, the first resin composition layer may be pre-heated at a temperature lower than the hardening temperature. For example, before the first resin composition layer is heat-hardened, the first resin composition layer may be pre-heated at a temperature of 50°C or higher and less than 120°C (preferably 60°C or higher and 115°C or lower, and more preferably 70°C or higher and 110°C or lower) for more than 5 minutes (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes).

Step (III) is a step of drilling holes in the first insulating layer. Through this step (III), holes such as through holes and through-holes can be formed in the first insulating layer. The drilling can be performed by, for example, a drilling machine, laser, plasma, etc., depending on the composition of the resin composition. The size and shape of the hole can be appropriately set according to the design of the multi-layer flexible substrate.

Step (IV) is a step of roughening the first insulating layer. Usually, in this step (IV), the slag is also removed. Therefore, the roughening treatment is sometimes also called the slag removal treatment. As an example of the roughening treatment, there can be listed a method of performing swelling treatment by swelling liquid, roughening treatment by oxidizing agent, and neutralization treatment by neutralizing liquid in this order.

Although not particularly limited, examples of the swelling liquid include alkaline aqueous solutions such as sodium hydroxide aqueous solution and potassium hydroxide aqueous solution. Examples of commercially available swelling liquids include "Swelling Dip Securiganth P" and "Swelling Dip Securiganth SBU" manufactured by Atotech Japan. The swelling treatment with the swelling liquid is performed by, for example, immersing the hardened body in the swelling liquid at 30 to 90°C for 1 to 20 minutes. From the viewpoint of suppressing the swelling of the resin of the insulating layer to an appropriate level, it is preferred to immerse the insulating layer in the swelling liquid at 40 to 80°C for 5 to 15 minutes.

Although not particularly limited, examples of the oxidizing agent include alkaline permanganic acid solutions in which permanganate is dissolved in an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution. The concentration of permanganate in the alkaline permanganic acid solution is preferably 5 mass% to 10 mass%. Examples of commercially available oxidizing agents include alkaline permanganic acid solutions such as "Concentrate ･ Compact P", "Concentrate ･ Compact CP", and "Dosing solution ･ Securiganth P" manufactured by Atotech Japan. Roughening treatment with an oxidizing agent can be performed by immersing the hardened body in an oxidizing agent solution heated to 60°C to 80°C for 10 minutes to 30 minutes.

In addition, as a neutralizing solution, an acidic aqueous solution is used. As a commercially available product, for example, "Reduction solution･Securigant P" manufactured by Atotech Japan Co., Ltd. can be listed. Treatment with a neutralizing solution can be performed by immersing the hardened body in a neutralizing solution at 30°C to 80°C for 5 minutes to 30 minutes. From the perspective of workability, it is preferred to immerse the hardened body in a neutralizing solution at 40°C to 70°C for 5 minutes to 20 minutes.

The arithmetic mean roughness (Ra) of the surface of the first insulating layer after the roughening treatment is preferably 400 nm or less, more preferably 300 nm or less, and even more preferably 200 nm or less. Although the lower limit is not particularly limited, it may be 30 nm or more, 40 nm or more, or 50 nm or more.

Step (V) is a step of forming a conductive layer on the first insulating layer if necessary. The conductive layer can be formed by, for example, coating, sputtering, evaporation, etc., of which coating is preferred. As a suitable example, a method of coating the surface of the first insulating layer with a conductive layer having a desired wiring pattern by a suitable method such as a semi-additive method or a full-additive method can be cited. Of these, from the perspective of simplicity of manufacturing, the semi-additive method is preferred.

The following is an example of forming a conductive layer by a semi-additive method. First, a plating seed layer is formed on the surface of the first insulating layer by electroless plating. Next, a mask pattern is formed on the formed plating seed layer to expose a portion of the plating seed layer in accordance with the desired wiring pattern. After a metal layer is formed on the exposed plating seed layer by electrolytic plating, the mask pattern is removed. Then, the unnecessary plating seed layer is removed by etching or other processes to form a conductive layer having the desired wiring pattern.

After obtaining the first insulating layer in step (II), if necessary, after carrying out step (III), step (IV), and step (V), step (VI) is carried out. Step (VI) is a step of laminating the second resin composition layer on the first insulating layer. The lamination of the first insulating layer and the second resin composition layer can be carried out in the same manner as the lamination of the sheet support substrate and the first resin composition layer in step (I).

However, when a resin sheet is used to form the first resin composition layer, the support of the resin sheet is removed before step (VI). The support may be removed between step (I) and step (II), between step (II) and step (III), between step (III) and step (IV), or between step (IV) and step (V).

After step (VI), step (VII) is performed. Step (VII) is a step of hardening the second resin composition layer to form a second insulating layer. The hardening of the second resin composition layer can be performed in the same manner as the hardening of the first resin composition layer in step (II). In this way, a laminated sheet including a first insulating layer and a second insulating layer, namely, a plurality of insulating layers, can be obtained.

In addition, in the method related to the above-mentioned embodiment, if necessary, the step of (VIII) drilling holes in the second insulating layer, the step of (IX) roughening the second insulating layer, and the step of (X) forming a conductive layer on the second insulating layer can be performed. The drilling of the second insulating layer in step (VIII) can be performed in the same method as the drilling of the first insulating layer in step (III). In addition, the roughening of the second insulating layer in step (IX) can be performed in the same method as the roughening of the first insulating layer in step (IV). Furthermore, the formation of the conductive layer on the second insulating layer in step (X) can be performed in the same manner as the formation of the conductive layer on the first insulating layer in step (V).

In the aforementioned embodiment, although the embodiment of manufacturing a laminated sheet by laminating and curing two resin composition layers, namely a first resin composition layer and a second resin composition layer, is described, a laminated sheet may also be manufactured by laminating and curing three or more resin composition layers. For example, in the method of the aforementioned embodiment, the lamination and curing of the resin composition layer through step (VI) to step (VII), and if necessary, the drilling of the insulating layer, the roughening treatment of the insulating layer, and the formation of the conductor layer on the insulating layer through step (VIII) to step (X) can be repeated to produce a laminated sheet. In this way, a laminated sheet including three or more insulating layers can be obtained.

Furthermore, the method of the aforementioned embodiment may include any steps other than the aforementioned steps. For example, when performing step (I), a step of removing the sheet support substrate may be performed.

<Multi-layer flexible substrate> The multi-layer flexible substrate includes a laminate sheet. The multi-layer flexible substrate may include only the laminate sheet, or may include arbitrary components combined with the laminate sheet. Examples of the arbitrary components include electronic components and cover films.

The multi-layered flexible substrate can be manufactured by a manufacturing method including the method of manufacturing the above-mentioned laminated sheet. Therefore, the multi-layered flexible substrate can be manufactured by a manufacturing method including (a) the step of preparing a resin sheet, and (b) the step of laminating and curing a plurality of resin composition layers using the resin sheet.

The method for manufacturing a multi-layer flexible substrate can be combined with the aforementioned steps and further include an arbitrary step. For example, the method for manufacturing a multi-layer flexible substrate having electronic components can include the step of bonding the electronic components to a laminate sheet. The bonding conditions of the laminate sheet and the electronic components can be arbitrary conditions such as a terminal electrode that can connect the electronic components to a conductor and a conductor layer that serves as a wiring provided on the laminate sheet. Furthermore, for example, the method for manufacturing a multi-layer flexible substrate having a covering film can include the step of bonding the laminate sheet and the covering film.

The aforementioned multi-layer flexible substrate is usually used in a manner that the surfaces of one side of the laminated sheets included in the multi-layer flexible substrate are bent and facing each other. For example, the multi-layer flexible substrate is stored in a frame of a semiconductor device in a bent and reduced size state. In another example, the multi-layer flexible substrate is installed in a movable portion of a semiconductor device having a bendable movable portion.

<Semiconductor device> The semiconductor device has the aforementioned multi-layer flexible substrate. The semiconductor device, for example, has a multi-layer flexible substrate and a semiconductor chip mounted on the multi-layer flexible substrate. In most semiconductor devices, the multi-layer flexible substrate can be stored in a frame of the semiconductor device, and the surfaces of one side of the laminated sheets included in the multi-layer flexible substrate can be bent and accommodated in a manner that they face each other.

Examples of semiconductor devices include various semiconductor devices used in electrical products (such as computers, mobile phones, digital cameras, and televisions) and vehicles (such as motorcycles, cars, trains, ships, and aircrafts).

The aforementioned semiconductor device can be manufactured, for example, by a manufacturing method including the steps of preparing a multi-layer flexible substrate, bending the multi-layer flexible substrate in a manner such that the surfaces of one side of the laminated sheet face each other, and housing the bent multi-layer flexible substrate in a frame. [Example]

The present invention is specifically described below by way of examples. The present invention is not limited to these examples. In addition, in the following, "parts" and "%" indicating amounts, unless otherwise specified, mean "parts by mass" and "% by mass", respectively. In addition, the operations described below are performed at room temperature and pressure (25°C, 1 atm) unless otherwise specified.

<Synthesis Example 1: Synthesis of Polyimide Resin 1> 50 g of G-3000 (bifunctional hydroxyl-terminated polybutadiene, number average molecular weight = 5,047 (GPC method), hydroxyl equivalent = 1,798 g/eq., solid content 100 mass %: manufactured by Nippon Soda Co., Ltd.), 23.5 g of Ipsol 150 (aromatic hydrocarbon mixed solvent: manufactured by Idemitsu Petrochemical Co., Ltd.), and 0.005 g of dibutyltin laurate were mixed and uniformly dissolved in a reaction container. When the mixture became uniform, the temperature was raised to 50° C., and 4.8 g of toluene-2,4-diisocyanate (isocyanate equivalent = 87.08 g/eq.) was added while stirring, and the mixture was reacted for about 3 hours. Next, the reaction product was cooled to room temperature, and 8.96 g of benzophenone tetracarboxylic dianhydride (anhydride equivalent = 161.1 g/eq.), 0.07 g of triethylenediamine, and 40.4 g of ethyl diglycol acetate (produced by Daicel) were added thereto, and the temperature was raised to 130°C while stirring, and the reaction was carried out for about 4 hours. The disappearance of the NCO peak at 2250 cm ^-1 was confirmed by FTIR. The confirmation of the disappearance of the NCO peak was regarded as the end point of the reaction. After the reaction product was cooled to room temperature, it was filtered with a 100 mesh filter cloth to obtain a polyimide resin 1 having an imide skeleton, a urethane skeleton, and a butadiene skeleton. Viscosity: 7.5Pa･s (25℃, E-type viscometer) Acid value: 16.9mgKOH/g Solid content: 50% by mass Number average molecular weight: 13,723 Glass transition temperature: -10℃ Content of polybutadiene structure: 50/(50+4.8+8.96)×100=78.4% by mass

<Synthesis Example 2: Synthesis of Polyimide Resin 2> In a 500 ml separable flask equipped with a nitrogen inlet tube and a stirring device, 9.13 g (30 mmol) of 5-amino-1,1'-biphenyl-2-yl 4-aminobenzoate, 15.61 g (30 mmol) of 4,4'-(4,4'-isopropylidene diphenoxy) diphthalic dianhydride, 94.64 g of N-methyl-2-pyrrolidone, 0.47 g (6 mmol) of pyridine, and 10 g of toluene were added. The imidization reaction was carried out at 180°C in a nitrogen environment for 4 hours while toluene was observed outside the system, thereby obtaining a polyimide solution containing polyimide resin 2 (non-volatile matter 20 mass %). In the polyimide solution, no precipitation of the synthesized polyimide resin 2 was observed. The weight average molecular weight of the polyimide resin 2 was 45,000.

<Synthesis Example 3: Synthesis of Polyimide Resin 3> In a reaction vessel equipped with a stirrer, a water separator, a thermometer, and a nitrogen inlet tube, 65.0 g of aromatic tetracarboxylic dianhydride ("BisDA-1000" manufactured by SABIC Japan, 4,4'-(4,4'-isopropylidene diphenoxy) diphthalic dianhydride), 266.5 g of cyclohexanone, and 44.4 g of methylcyclohexane were placed, and the solution was heated to 60°C. Then, 43.7 g of dimer diamine ("PRIAMINE 1075" manufactured by Croda Japan) and 5.4 g of 1,3-bis(aminomethyl)cyclohexane were dropped, and the imidization reaction was carried out at 140°C for 1 hour. Thus, a polyimide solution (non-volatile matter: 30 mass %) containing polyimide resin 3 was obtained. The weight average molecular weight of polyimide resin 3 was 25,000.

<Synthesis Example 4: Synthesis of Polyimide Resin 4> A 500 mL separable flask equipped with a water quantity receiver connected to a circulation cooler, a nitrogen inlet tube and a stirrer was prepared. 20.3 g of 4,4'-oxydiphthalic anhydride (ODPA), 200 g of γ-butyrolactone, 20 g of toluene and 29.6 g of 5-(4-aminophenoxy)-3-[4-(4-aminophenoxy)phenyl]-1,1,3-trimethyldihydroindene were added to the flask and stirred at 45°C for 2 hours under a nitrogen flow to react. Then, the reaction solution was heated to about 160°C while the condensed water was removed azeotropically with toluene under a nitrogen flow. Confirm that a specified amount of water accumulates in the moisture quantitative receptor and until no water outflow is observed. After confirmation, the reaction solution is further heated and stirred at 200°C for 1 hour. Then, it is cooled to obtain a polyimide solution (non-volatile matter 20% by mass) containing polyimide resin 4 having a 1,1,3-trimethylindene skeleton. The obtained polyimide resin 4 has a repeating unit represented by the following formula (X1) and a repeating unit represented by the following formula (X2). In addition, the weight average molecular weight of the aforementioned polyimide resin 4 is 12,000.

<Example 1: Preparation of Resin Composition 1> 5 parts of bixylenol epoxy resin ("YX4000HK" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent of about 185 g/eq.), 5 parts of naphthalene epoxy resin ("ESN475V" manufactured by Nippon Steel & Sumitomo Chemical Corporation, epoxy equivalent of about 332 g/eq.), 5 parts of bisphenol AF epoxy resin (" 10 parts of cyclohexane-type epoxy resin ("ZX1658GS" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent of about 135 g/eq.), 2 parts of polyimide resin 1 obtained in Synthesis Example 1 (non-volatile component 50 mass %) were stirred and heated to dissolve in 10 parts of cyclohexanone. After cooling to room temperature, 4 parts of a cresol novolac curing agent containing a triazine skeleton ("LA3018-50P" manufactured by DIC Corporation, a hydroxyl equivalent of about 151 g/eq., a 2-methoxypropanol solution containing 50% of non-volatile matter), 6 parts of an active ester curing agent ("EXB-8000L-65TM" manufactured by DIC Corporation, an active group equivalent of about 220 g/eq., a MEK solution containing 65% of non-volatile matter by mass), and spherical silica ("SC2500SQ" manufactured by Admatechs Corporation, an average particle size of 0.5 μm, a specific surface area of 11.2 ^m2 ) were mixed therewith. /g, 25 parts of N-phenyl-3-aminopropyltrimethoxysilane (KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.) surface-treated with 1 part of N-phenyl-3-aminopropyltrimethoxysilane (KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.) relative to 100 parts of silica, 6 parts of an epoxy resin containing a siloxane skeleton (KR470, manufactured by Shin-Etsu Chemical Co., Ltd., epoxy equivalent of about 200 g/eq.), and 0.2 parts of an amine-based curing accelerator (4-dimethylaminopyridine (DMAP)) were uniformly dispersed with a high-speed rotary mixer and filtered with a cartridge filter (SHP020, manufactured by ROKITECHNO Co., Ltd.) to prepare a resin composition 1.

<Example 2: Preparation of Resin Composition 2> Except that 100 parts of polyimide resin 2 (non-volatile component 20% by mass) obtained in Synthesis Example 2 were used instead of 40 parts of polyimide resin 1 (non-volatile component 50% by mass) obtained in Synthesis Example 1, the same operation as in Example 1 was performed to prepare resin composition 2.

<Example 3: Preparation of Resin Composition 3> Resin Composition 3 was prepared by the same operation as in Example 1 except that 66.7 parts of polyimide resin 3 (non-volatile component 30% by mass) obtained in Synthesis Example 3 were used instead of 40 parts of polyimide resin 1 (non-volatile component 50% by mass) obtained in Synthesis Example 1.

<Example 4: Preparation of Resin Composition 4> Resin composition 4 was prepared by the same operation as in Example 1, except that 100 parts of polyimide resin 4 (non-volatile component 20% by mass) obtained in Synthesis Example 4 was used instead of 40 parts of polyimide resin 1 (non-volatile component 50% by mass) obtained in Synthesis Example 1.

<Comparative Example 1: Preparation of Resin Composition 5>

Except for not using 6 parts of epoxy resin containing a siloxane skeleton (manufactured by Shin-Etsu Chemical Co., Ltd., "KR470", epoxy equivalent of about 200 g/eq.), the same operation as in Example 1 was performed to prepare resin composition 5.

<Comparative Example 2: Preparation of Resin Composition 6>

Except for replacing 40 parts of polyimide resin 1 (non-volatile component 50 mass%) obtained in Synthesis Example 1 with 66 parts of phenoxy resin ("YX7553BH30" manufactured by Mitsubishi Chemical Corporation, solid component 30 mass%), the same operations as in Example 1 were performed to prepare resin composition 6.

<Test Example 1: Evaluation of Softness (MIT Folding Resistance)>

The resin composition of each embodiment and comparative example was uniformly coated on the mold release treatment surface of a PET film (thickness 38μm) treated with an alkyd mold release agent in a die coater so that the thickness of the resin composition layer after drying became 40μm, and dried at 80~120℃ (average 100℃) for 6 minutes to obtain a resin sheet 1.

The obtained resin sheet 1 was laminated on a polyimide film (UPILEX S, manufactured by Ube Industries, Ltd.) using a batch vacuum pressure laminating press (MVLP-500 manufactured by Meiki Manufacturing Co., Ltd.) to obtain a resin sheet with a protective film. The laminating process was to reduce the pressure for 30 seconds to a pressure of 13 hPa or less, and then press at 120°C for 30 seconds and a pressure of 0.74 MPa. Then, the resin composition was cured at 190°C for 90 minutes by peeling off the PET film, and the polyimide film was peeled off to obtain a cured sample.

The obtained hardened sample was cut into test pieces with a width of 15 mm and a length of 110 mm. The MIT test device (MIT folding fatigue tester "MIT-DA" manufactured by Toyo Seiki Seisakusho) was used to measure the number of folding times of the hardened body until it broke under the test conditions of load 2.5N, bending angle 90 degrees, bending radius 1.0mm, and bending speed 175 times/minute in accordance with JIS C-5016. The test was performed on 5 samples, and the average value of the top 3 points was calculated. The case where the folding times were less than 8,000 times was evaluated as "×", and the case where the folding times were more than 8,000 times was evaluated as "○".

<Test Example 2: Evaluation of viscosity (adhesion)>

The protective film was peeled off from the resin sheet with protective film obtained in Test Example 1, and the adhesive force of the resin composition layer was measured at a temperature of 80°C using a probe adhesion tester (TESTER Industrial Co., Ltd., "TE-6002") on a glass with a diameter of 5 mm, with a load of 1 kgf/ ^cm2 , a contact speed of 0.5 mm/sec, a tensile speed of 0.5 mm/sec, and a holding time of 10 seconds. The adhesive force exceeding 1.6 N was evaluated as "×", and the adhesive force below 1.6 N was evaluated as "○".

<Test Example 3: Evaluation of Insulation Reliability> (1) Base processing of inner layer circuit board

As the inner circuit substrate, a glass cloth-based epoxy resin double-sided copper-clad laminate (copper foil thickness 3μm, substrate thickness 0.15mm, "HL832NSF LCA" manufactured by Mitsubishi Gas Chemical Co., Ltd., 255×340mm size) with circuit conductors (copper) formed in a wiring pattern of L/S=10μm/10μm on both sides was prepared. Both sides of the inner circuit substrate were treated with an organic film on the copper surface using "FlatBOND-FT" manufactured by MEC.

(2) Lamination of resin sheets The protective film was peeled off from the resin sheet with protective film obtained in Test Example 1, and the resin composition layer was pressed on both sides of the inner circuit board using a batch vacuum pressure laminating press (manufactured by Nikko Materials Co., Ltd., two-stage stacking laminating press, CVP700) in such a way that the resin composition layer was in contact with the inner circuit board. Lamination was performed by reducing the pressure for 30 seconds to set the air pressure to less than 13hPa, and pressing at 130°C, a pressure of 0.74MPa, and 45 seconds. Then, hot pressing was performed at 120°C and a pressure of 0.5MPa for 75 seconds.

(3) Thermal curing of the resin composition layer The inner circuit board of the laminated resin sheet is placed in an oven at 100°C for 30 minutes, then transferred to an oven at 180°C for 30 minutes to thermally cure and form an insulating layer, and then the release PET is peeled off.

(4) Roughening treatment The inner circuit substrate on which the insulating layer is formed is subjected to a desmearing treatment as a roughening treatment. In addition, as the desmearing treatment, the following wet desmearing treatment is performed. Wet degumming treatment: Immerse in a swelling solution ("Swelling Dip Securigant P" manufactured by Atotech Japan, an aqueous solution of diethylene glycol monobutyl ether and sodium hydroxide) at 60°C for 5 minutes, then immerse in an oxidizing solution ("Concentrate Compact CP" manufactured by Atotech Japan, an aqueous solution of potassium permanganate with a concentration of about 6% and sodium hydroxide with a concentration of about 4%) at 80°C for 10 minutes, and finally immerse in a neutralizing solution ("Reduction solution Securigant P" manufactured by Atotech Japan, an aqueous solution of sulfuric acid) at 40°C for 5 minutes, and then dry at 80°C for 15 minutes. This is designated as "roughened substrate A".

(5) Conductive layer formation (5-1) Electroless plating In order to form a conductive layer on the surface of the roughened substrate A, a plating step including the following steps 1 to 6 (a copper plating step using a chemical solution manufactured by Atotech Japan) is performed to form a conductive layer.

1. Alkaline cleaning (cleaning and charge adjustment of the surface of the insulating layer) The surface of the roughened substrate A was cleaned with Cleaning Cleaner Securiganth 902 (trade name) at 60°C for 5 minutes. 2. Soft etching (cleaning in through holes) The surface of the roughened substrate A was treated with a sulfuric acid-acid sodium peroxodisulfate aqueous solution at 30°C for 1 minute. 3. Pre-dip (for charge adjustment of the surface of the Pd-added insulating layer) The surface of the roughened substrate A was treated with Pre. Dip Neoganth B (trade name) at room temperature for 1 minute. 4. Activator application (application of Pd to the surface of the insulating layer) The surface of the roughened substrate A was treated with Activator Neoganth 834 (trade name) at 35°C for 5 minutes. 5. Reduction (reduction of Pd applied to the insulating layer) The surface of the roughened substrate A was treated with a mixture of Reducer Neoganth WA (trade name) and Reducer Acceralator 810 mod. (trade name) at 30°C for 5 minutes. 6. Electroless copper plating (Cu is deposited on the surface of the insulating layer (Pd surface)) The surface of the roughened substrate A was treated at 35°C for 20 minutes using a mixture of Basic Solution Printganth MSK-DK (trade name), Copper Solution Printganth MSK (trade name), Stabilizer Printganth MSK-DK (trade name), and Reducer Cu (trade name) to form an electroless copper plating layer. The thickness of the formed electroless copper plating layer was 0.8μm.

(5-2) Electrolytic plating Then, using a chemical solution made by Atotech Japan, an electrolytic copper plating step was performed under conditions that copper was filled into the through hole. Then, as an anti-etching pattern for patterning by etching, a connection pad pattern with a diameter of 1 mm that was connected to the lower conductor and a circular conductor pattern with a diameter of 10 mm that was not connected to the lower conductor were used to form a conductor layer with a thickness of 10 μm on the surface of the insulating layer. Then, an annealing treatment was performed at 200°C for 90 minutes. This substrate was designated as "Evaluation Substrate A".

(6) Evaluation of insulation reliability of insulation layer The 10 mm diameter round conductor side of the evaluation substrate A was set as the + electrode, and the grid circuit conductor (copper) side of the inner circuit substrate connected to the 1 mm diameter connection pad was set as the - electrode. The insulation resistance value after 100 hours was measured using a highly accelerated life tester ("PM422" manufactured by ETAC) at 110°C, 85% relative humidity, and 20 V DC voltage application. This measurement was performed 6 times, and the resistance value of all the test pieces at the 6 points was set to 1.00 × 10 ⁸ The case of Ω or more was rated as "○", and the case of less than 1.00×10 ⁸ Ω even if there was one was rated as "×". The evaluation results and insulation resistance values are shown in the following table. The insulation resistance values listed in the following Table 1 are the lowest values of the insulation resistance values of the 6-point test pieces.

The amounts of non-volatile components used in the resin compositions of Examples and Comparative Examples, the measurement results of the test examples, the evaluation results, etc. are shown in Table 1 below.

It was found that by using a resin composition comprising (A) an epoxy resin, (B) an inorganic filler and (C) a polyimide resin, wherein the component (A) comprises (A-1) an epoxy resin having a siloxane skeleton, it is possible to obtain a cured product having excellent flexibility and excellent insulation reliability while suppressing the viscosity even when the content of the inorganic filler (B) is low.

Claims (22)

A resin composition comprising (A) an epoxy resin, (B) an inorganic filler, (C) a polyimide resin, and (D) a curing agent, wherein: (A) component comprises (A-1) an epoxy resin containing a siloxane skeleton, (A-1) component is an epoxy resin containing a cyclic siloxane skeleton, (C) component is (1) a resin obtained by an imidization reaction of a diamine compound and tetracarboxylic anhydride, or (2) a resin obtained by an imidization reaction of a diisocyanate compound and tetracarboxylic anhydride, and (D) component is selected from One or more of the curing agents selected from the group consisting of phenolic curing agents, naphthol curing agents, active ester curing agents, benzoxazine curing agents, cyanate ester curing agents and carbodiimide curing agents, wherein the content of component (A) is 10% by mass or more, based on the non-volatile components in the resin composition being 100% by mass, the content of component (B) is 40% by mass or less, based on the non-volatile components in the resin composition being 100% by mass, and the content of component (C) is 5% by mass or more, based on the non-volatile components in the resin composition being 100% by mass. The resin composition of claim 1, wherein the tetracarboxylic anhydride contains a tetracarboxylic anhydride selected from aliphatic tetracarboxylic dianhydride and diphthalic dianhydride. The resin composition of claim 1, wherein the diamine compound contains a diamine compound selected from aliphatic diamine compounds and diphenylamine compounds, and the diisocyanate compound contains a diisocyanate compound selected from aliphatic diisocyanate compounds, diisocyanate benzene compounds, and diisocyanate polyurethane compounds with isocyanate groups at both ends. The resin composition of claim 1, wherein the tetracarboxylic anhydride contains tetracarboxylic anhydride selected from aliphatic tetracarboxylic dianhydride and diphthalic dianhydride containing oxygen atoms as skeleton atoms, the diamine compound contains a diamine compound selected from aliphatic diamine compounds and diphenylamine compounds, and the diisocyanate compound contains a diisocyanate compound selected from aliphatic diisocyanate compounds, diisocyanatobenzene compounds, and diisocyanate polyurethanes with isocyanate groups at both ends. The resin composition of claim 3, wherein the diamine compound contains an aliphatic diamine compound, and the diisocyanate compound contains a diisocyanate compound selected from an aliphatic diisocyanate compound and a diisocyanate compound of a polyurethane having isocyanate groups at both ends obtained by subjecting an aliphatic diisocyanate compound to a urethanization reaction with a polymer having hydroxyl groups at both ends. The resin composition of claim 1, wherein the component (A-1) is a compound represented by formula (A1),

[In the formula, ^R1 independently represents an alkylene oxide group; ^R2 independently represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted aryl group; ^R3 and ^R4 independently represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted aryl group, or ^R3 and ^R4 together show one -O- and are bonded to each other to form a cyclosiloxane skeleton; s represents an integer greater than 1]. The resin composition of claim 1, wherein the molecular weight of component (A-1) is 800 or less. The resin composition of claim 1, wherein the epoxy equivalent of component (A-1) is 150 g/eq. to 250 g/eq. The resin composition of claim 1, wherein the content of component (A-1) is 5% by mass or more when the non-volatile components in the resin composition are taken as 100% by mass. The resin composition of claim 1, wherein the content of component (A-1) is 10% by mass or less when the non-volatile components in the resin composition are taken as 100% by mass. The resin composition of claim 1, wherein the average particle size of component (B) is less than 1 μm. The resin composition of claim 1, wherein component (B) is silicon dioxide. The resin composition of claim 1, wherein the weight average molecular weight of component (C) is greater than 1,000 and less than 100,000. The resin composition of claim 1, wherein the content of component (C) is 20% by mass or more when the non-volatile components in the resin composition are taken as 100% by mass. In the resin composition of claim 1, the content of component (C) is 30% by mass or less when the non-volatile components in the resin composition are taken as 100% by mass. The resin composition of claim 1, wherein component (D) comprises an active ester hardener. The resin composition of claim 1 is used to form an insulating layer of a multi-layer flexible substrate. For example, the resin composition of claim 1 is uniformly coated on the release treatment surface of a PET film treated with an alkyd release agent, so that the thickness of the resin composition layer after drying becomes 40 μm, and is dried at 80-120°C (average 100°C) for 6 minutes to form a sheet. The adhesion of the resin composition layer measured under the conditions of a glass probe diameter of 5 mm, a load of 1 kgf/ ^cm2 , a contact speed of 0.5 mm/second, a tensile speed of 0.5 mm/second, a holding time of 10 seconds, and a temperature of 80°C is 1.8 N or less. A cured product of a resin composition as described in any one of claim items 1 to 18. A resin sheet comprising a support, and a resin composition layer formed by a resin composition as described in any one of claims 1 to 18 disposed on the support. A multi-layer flexible substrate comprising an insulating layer formed by curing a resin composition as described in any one of claims 1 to 18. A semiconductor device having a multi-layer flexible substrate as described in claim 21.