TWI880921B - Resin composition - Google Patents

Abstract

[Topic] To provide a resin composition that maintains excellent flexibility while suppressing tackiness. [Solution] A resin composition comprising (A) a thermosetting resin, (B) an inorganic filler, (C) an organic filler, and (D) an adhesive softener, wherein the content of the component (C) is 5% by mass or more when the non-volatile components in the resin composition are 100% by mass.

Description

Resin composition

The present invention relates to a resin composition containing a thermosetting resin and an inorganic filler.

In recent years, there has been an increasing demand for thinner, lighter, and more densely mounted semiconductor components. In response to this demand, the use of flexible substrates as substrate boards for semiconductor components has attracted attention. Flexible substrates can be thinner and lighter than rigid substrates. Furthermore, since flexible substrates are soft and deformable, they can be folded for installation.

The insulating material of the flexible substrate generally needs to be combined with a softening resin component, but the combination with a softening resin component may increase the adhesiveness (tackiness) and make the workability poor. In this case, the adhesiveness can be suppressed by combining with an inorganic filler (Patent Document 1), but as the combination rate of the inorganic filler increases, it is difficult to have flexibility. [Prior Technical Document] [Patent Document]

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

[The problem that the invention wants to solve]

Therefore, the present invention aims to provide a resin composition that maintains excellent softness while suppressing adhesiveness. [Means for solving the problem]

In order to achieve the subject of the present invention, the inventors of the present invention have made great efforts to review the results and found that by combining a resin composition containing (A) a thermosetting resin, (D) an adhesive softener, and (B) an inorganic filler with 5% by mass or more of (C) an organic filler, it is possible to maintain excellent flexibility while suppressing adhesiveness, thereby completing the present invention.

That is, the present invention includes the following contents. [1] A resin composition comprising (A) a thermosetting resin, (B) an inorganic filler, (C) an organic filler, and (D) an adhesive softener, wherein the content of the component (C) is 5% by mass or more when the non-volatile components in the resin composition are 100% by mass. [2] The resin composition described in [1] above, wherein the content of the component (B) is 50% by mass or less when the non-volatile components in the resin composition are 100% by mass. [3] The resin composition described in [1] or [2] above, wherein the content of the component (C) is 10% by mass or less when the non-volatile components in the resin composition are 100% by mass. [4] A resin composition as described in any one of [1] to [3] above, wherein the component (D) is selected from the group consisting of a resin having a polybutadiene structure, a polyrotaxane resin, a polyimide resin, and a maleimide resin having a dimer acid skeleton. [5] A resin composition as described in any one of [1] to [4] above, wherein the content of the component (D) is 1% by mass or more when the non-volatile components in the resin composition are 100% by mass. [6] A resin composition as described in any one of [1] to [5] above, wherein the organic filler (C) is a core-shell type graft copolymer particle. [7] The resin composition described in [6] above, wherein the monomer component forming the shell portion of the core-shell graft copolymer particles is a (meth)acrylate. [8] The resin composition described in [6] or [7] above, wherein the core particles of the core-shell graft copolymer particles contain a thermoplastic elastomer. [9] The resin composition described in any one of [1] to [8] above, wherein the component (A) is an epoxy resin. [10] The resin composition described in any one of [1] to [9] above, further comprising a hardener (E). [11] The resin composition described in [10] above, wherein the component (E) contains an active ester hardener. [12] A resin composition as described in any one of [1] to [11] above, wherein the solid content of the resin composition is 95% by mass or less. [13] A resin composition as described in any one of [1] to [12] above, which is used to form an insulating layer of a multi-layer flexible substrate. [14] A cured product of the resin composition as described in any one of [1] to [13] above. [15] A resin sheet comprising a support and a resin composition layer formed of the resin composition as described in any one of [1] to [13] above and disposed on the support. [16] A multi-layer flexible substrate comprising an insulating layer formed by curing the resin composition described in any one of [1] to [13]. [17] A semiconductor device comprising the multi-layer flexible substrate described in [16]. [Effect of the invention]

According to the resin composition of the present invention, it is possible to maintain excellent softness while suppressing adhesiveness. [Best form of implementing the invention]

The present invention is described in detail below in its appropriate implementation form. However, the present invention is not limited to the following implementation forms and examples, and can be implemented with any changes within the scope of the patent application of the present invention and its equivalent scope.

<Resin composition> The resin composition of the present invention contains (A) a thermosetting resin, (B) an inorganic filler, (C) an organic filler, and (D) an adhesive softener. The content of the component (C) is 5% by mass or more when the non-volatile components in the resin composition are 100% by mass.

By using such a resin composition, it is possible to maintain excellent softness while suppressing tackiness.

The resin composition of the present invention may contain any component in addition to (A) thermosetting resin, (B) inorganic filler, (C) organic filler, and (D) adhesive softener. The optional component may include (E) hardener, (F) hardening accelerator, (G) other additives, and (H) organic solvent. The following is a detailed description of each component contained in the resin composition.

<(A) Thermosetting resin> The resin composition of the present invention contains (A) thermosetting resin. (A) Thermosetting resin does not contain a corresponding amount of (D) component. (A) Thermosetting resin can be a known one, although not particularly limited, such as polyester resin, polyurethane resin, polyester urethane resin, butyral resin, acrylic resin, cyanate resin, polysilicone resin, cyclohexane resin, melamine resin, etc. Among them, epoxy resin is preferred.

Epoxy resins include, for example, bisxylenol 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-catechol epoxy resins, naphthalene epoxy resins, naphthol epoxy resins, anthracene epoxy resins, Resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, spirocyclic epoxy resin, oxalic acid type epoxy resin, oxalic acid dimethanol type epoxy resin, naphthyl ether type epoxy resin, trihydroxymethyl type epoxy resin, tetraphenylethane type epoxy resin, etc. The 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 the epoxy resin. From the viewpoint of significantly obtaining the desired effect of the present invention, the ratio of the epoxy resin having two or more epoxy groups in one molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more relative to 100% by mass of the non-volatile component of the epoxy resin.

Epoxy resins include epoxy resins that are liquid at 20°C (hereinafter referred to as "liquid epoxy resins") and epoxy resins that are solid at 20°C (hereinafter 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 epoxy resins, but it is preferred to contain 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.

The liquid epoxy resin is preferably a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol AF type epoxy resin, a naphthalene type epoxy resin, a glycidyl ester type epoxy resin, a glycidyl amine type epoxy resin, a phenol novolac type epoxy resin, an alicyclic epoxy resin having an ester skeleton, a cyclohexane type epoxy resin, a cyclohexanedimethanol type epoxy resin, and a glycidyl amine type epoxy resin.

Specific examples of liquid epoxy resins include "HP4032", "HP4032D", and "HP4032SS" (naphthalene-type epoxy resins) manufactured by DIC Corporation; "828US", "828EL", "jER828EL", "825", and "EPIKOTE828EL" (bisphenol A-type epoxy resins) manufactured by Mitsubishi Chemical Corporation; and "jE R807", "1750" (bisphenol F type epoxy resin); "jER152" (phenol novolac type epoxy resin) manufactured by Mitsubishi Chemical; "630" and "630LSD" (glycidylamine type epoxy resin) manufactured by Mitsubishi Chemical; "ZX1059" (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd.; Nagase "EX-721" (glycidyl ester type epoxy resin) manufactured by ChemteX; "Celloxide 2021P" (aliphatic epoxy resin with ester skeleton) manufactured by Daicel; "ZX1658" and "ZX1658GS" (liquid 1,4-glycidyl cyclohexane type epoxy resin) manufactured by Nippon Steel & Sumitomo Metal Chemicals Co., Ltd. These can be used alone or in combination of two or more.

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.

The solid epoxy resin is preferably a dixylenol type epoxy resin, a naphthalene type epoxy resin, a naphthalene type tetrafunctional epoxy resin, a cresol novolac type epoxy resin, a dicyclopentadiene type epoxy resin, a triphenol type epoxy resin, a naphthol type epoxy resin, a biphenyl type epoxy resin, a naphthyl ether type epoxy resin, anthracene type epoxy resin, a bisphenol A type epoxy resin, a bisphenol AF type epoxy resin, or a tetraphenylethane type epoxy resin.

Specific examples of solid epoxy resins include "HP4032H" (naphthalene-type epoxy resin) manufactured by DIC Corporation; "HP-4700" and "HP-4710" (naphthalene-type tetrafunctional epoxy resin) manufactured by DIC Corporation; "N-690" (cresol novolac-type epoxy resin) manufactured by DIC Corporation; "N-695" (cresol novolac-type epoxy resin) manufactured by DIC Corporation; "HP-7200", "HP-7200HH", and "HP-7200H" (dicyclopentadiene-type cyclopentadiene-type epoxy resin) manufactured by DIC Corporation. "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthyl ether type epoxy resin) manufactured by DIC Corporation; "EPPN-502H" (triphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC3000H", "NC3000", "NC3000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd. ", "NC3100" (biphenyl type epoxy resin); "ESN475V" (naphthol type epoxy resin) manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd.; "ESN485" (naphthol novolac type epoxy resin) manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd.; "YX4000H", "YX4000", "YL6121" (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX4000HK" (bisxylenol type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX8800" (anthracene type epoxy resin) manufactured by Mitsubishi Chemical Corporation "YX7700" manufactured by Mitsubishi Chemical (a novolac epoxy resin containing xylene structure); "PG-100" and "CG-500" manufactured by Osaka Gas Chemical; "YL7760" manufactured by Mitsubishi Chemical (a bisphenol AF epoxy resin); "YL7800" manufactured by Mitsubishi Chemical (a fluorene epoxy resin); "jER1010" manufactured by Mitsubishi Chemical (a solid bisphenol A epoxy resin); "jER1031S" manufactured by Mitsubishi Chemical (a tetraphenylethane epoxy resin), etc. These can be used alone or in combination of two or more.

When the epoxy resin is used in combination with a liquid epoxy resin and a solid epoxy resin, the mass ratio of the liquid epoxy resin to the solid epoxy resin is preferably 1:1 to 1:50, more preferably 1:3 to 1:30, and particularly preferably 1:5 to 1:20. When the mass ratio of the liquid epoxy resin to the solid epoxy resin is within this range, the desired effect of the present invention can be significantly obtained.

The epoxy equivalent of the epoxy resin is preferably 50 g/eq. to 5,000 g/eq., more preferably 50 g/eq. to 3,000 g/eq., still more preferably 80 g/eq. to 2,000 g/eq., and still more preferably 110 g/eq. to 1,000 g/eq. Within this range, the crosslinking density of the cured product of the resin composition becomes sufficient, and an insulating layer with a small surface roughness can be obtained. The epoxy equivalent is the mass of the resin containing 1 equivalent of epoxy groups. The epoxy equivalent can be measured in accordance with JIS K7236.

The weight average molecular weight (Mw) of the epoxy resin is preferably 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500 from the viewpoint of significantly obtaining the desired effect of the present invention. The weight average molecular weight of the resin can be measured as a value converted to polystyrene by colloid permeation chromatography (GPC).

The content of the thermosetting resin (A) is not particularly limited, but when the non-volatile components in the resin composition are 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 thermosetting resin (A) is not particularly limited, but when the non-volatile components in the resin composition are 100% by mass, it 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.

<(B) Inorganic filler> The resin composition of the present invention contains (B) an inorganic filler.

(B) The material of the inorganic filler is not particularly limited, and examples thereof include silicon dioxide, alumina, glass, cordierite, silica oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, alumina, alumina, 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, with silicon dioxide being particularly preferred. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, hollow silica, etc. Preferably, the silica is spherical silica. (B) The inorganic filler may be used alone or in combination of two or more.

(B) The average particle size of the inorganic filler is not particularly limited, but from the viewpoint of obtaining the desired effect of the present invention, it is preferably 10 μm or less, more preferably 5 μm or less, further preferably 3 μm or less, further more preferably 2 μm or less, and particularly preferably 1 μm or less. From the viewpoint of obtaining the desired effect of the present invention, the lower limit of the average particle size of the inorganic filler is preferably 0.01 μm or more, more preferably 0.05 μm or more, further preferably 0.1 μm or more, further more preferably 0.2 μm or more, and particularly preferably 0.25 μm or more. 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 used for measurement. The measurement sample can be made by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone in a small bottle and dispersing them by ultrasound for 10 minutes. The sample is measured using a laser diffraction particle size distribution measuring device, using a light source wavelength of blue and red, and the flow cell method to measure the particle size distribution of the inorganic filler on a volume basis. The average particle size as the median diameter is calculated from the obtained particle size distribution. Examples of laser diffraction particle size distribution measuring devices include "LA-960" manufactured by Horiba, Ltd.

(B) Commercially available products of inorganic fillers include, for example, "UFP-30" manufactured by Denka Kagaku Kogyo Co., Ltd.; "SP60-05" and "SP507-05" manufactured by New Nittetsu Sumikin Materials Company; "YC100C", "YA050C", "YA050C-MJE", and "YA010C" manufactured by Admatex; "UFP-30" manufactured by Denka Company; "Silfil NSS-3N", "Silfil NSS-4N", and "Silfil NSS-5N" manufactured by Tokuyama Corporation; "SC2500SQ", "SO-C4", "SO-C2", and "SO-C1" manufactured by Admatex; and the like.

(B) In order to improve moisture resistance and dispersibility, the inorganic filler is preferably treated with one or more surface treatment agents such as aminosilane coupling agents, epoxysilane coupling agents, butylsilane coupling agents, alkoxysilane compounds, organic silazane compounds, and titanium ester coupling agents. Commercially available surface treatment agents include "KBM403" (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical, "KBM803" (3-butylpropyltrimethoxysilane) manufactured by Shin-Etsu Chemical, "KBE903" (3-aminopropyltriethoxysilane) manufactured by Shin-Etsu Chemical, and "KBM573" (N-phenyl-3- "Aminopropyltrimethoxysilane", "SZ-31" (hexamethyldisilazane) manufactured by Shin-Etsu Chemical, "KBM103" (phenyltrimethoxysilane) manufactured by Shin-Etsu Chemical, "KBM-4803" (long-chain epoxy type silane coupling agent) manufactured by Shin-Etsu Chemical, "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane) manufactured by Shin-Etsu Chemical, etc.

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

The degree of surface treatment of 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 melt viscosity of the resin composition or the melt viscosity of the sheet form from increasing, it is preferably 1 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 after the surface-treated inorganic filler is washed with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler surface-treated with a surface treatment agent, and ultrasonic washing is performed at 25°C for 5 minutes. After removing the supernatant and drying the solids, the amount of carbon per unit surface area of the inorganic filler can be measured using a carbon analyzer. The carbon analyzer that can be used is "EMIA-320V" manufactured by Horiba, Ltd.

(B) The specific surface area of the inorganic filler is preferably 1 m ² /g or more, more preferably 2 m ² /g or more, and particularly preferably 3 m ² /g or more. The upper limit is not particularly limited, but is preferably 50 m ² /g or less, and more preferably 20 m ² /g or less. The specific surface area of the inorganic filler can be obtained by adsorbing nitrogen gas on the sample surface according to the BET method using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountek) and using the BET multipoint method to calculate the specific surface area.

(B) The content of the inorganic filler is preferably 70% by mass or less, more preferably 60% by mass or less, further preferably 50% by mass or less, and particularly preferably 45% by mass or less, based on 100% by mass of the non-volatile components in the resin composition, from the viewpoint of obtaining a cured product with better flexibility. (B) The lower limit of the content of the inorganic filler is not particularly limited, but from the viewpoint of obtaining a cured product with sufficient mechanical strength, it is preferably 20% by mass or more, more preferably 30% by mass or more, further preferably 35% by mass or more, and particularly preferably 38% by mass or more, based on 100% by mass of the non-volatile components in the resin composition.

<(C) Organic filler> The resin composition of the present invention contains (C) organic filler. (C) Organic filler does not contain an organic filler equivalent to (D). By including (C) component in the resin composition, the adhesiveness can be reduced and the workability can be improved.

(C) The organic filler exists in the resin composition in the form of particles. Examples of the organic filler (C) include rubber particles, polyamide particles, polysilicone particles, etc. In the present invention, rubber particles are preferably used from the viewpoint of significantly obtaining the desired effect of the present invention.

The rubber component contained in the rubber particles may include, for example, olefinic thermoplastic elastomers such as polybutadiene, polyisoprene, polychloroprene, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-isobutylene copolymer, acrylonitrile-butadiene copolymer, isoprene-isobutylene copolymer, isobutylene-butadiene copolymer, ethylene-propylene-diene terpolymer, ethylene-propylene-butylene terpolymer, etc.; and thermoplastic elastomers such as acrylic thermoplastic elastomers such as poly(meth)propyl acrylate, poly(meth)butyl acrylate, poly(meth)cyclohexyl acrylate, poly(meth)octyl acrylate, etc., preferably olefinic thermoplastic elastomers, more preferably styrene-butadiene copolymer. Furthermore, the rubber component may be mixed with a polysilicone rubber or the like. The rubber component contained in the rubber particles has a glass transition temperature of, for example, 0°C or less, preferably -10°C or less, more preferably -20°C or less, and even more preferably -30°C or less.

(C) Organic fillers are preferably core-shell type particles from the viewpoint of significantly obtaining the expected effects of the present invention. Core-shell type particles refer to organic fillers in particle form composed of core particles containing the rubber components listed above and a shell portion covering the core particles with one or more layers. Furthermore, core-shell type particles are preferably core-shell type graft copolymer particles composed of core particles containing the rubber components listed above and a shell portion graft-copolymerized with a monomer component copolymerizable with the rubber component contained in the core particles. The core-shell type herein does not necessarily refer only to those in which the core particle and the shell portion are clearly distinguishable, but also includes those in which the boundary between the core particle and the shell portion is not obvious, and the core particle may not be completely covered by the shell portion.

The rubber component is preferably contained in the core-shell graft copolymer particles in an amount of 40 mass % or more, more preferably 50 mass % or more, and even more preferably 60 mass % or more. The upper limit of the content of the rubber component in the core-shell graft copolymer particles is not particularly limited, but from the viewpoint of sufficient coverage of the core particles by the shell, it is, for example, 95 mass % or less, preferably 90 mass %.

The monomer components forming the shell part of the core-shell graft copolymer particles include, for example, (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, octyl (meth)acrylate, glycidyl (meth)acrylate, etc.; (meth)acrylic acid; N-substituted maleimides such as N-methylmaleimide and N-phenylmaleimide; maleimide; α,β-unsaturated carboxylic acids such as maleic acid and itaconic acid; aromatic vinyl ester compounds such as styrene, 4-vinyltoluene, α-methylstyrene, etc.; (meth)acrylonitrile, etc., with (meth)acrylates being preferred and methyl (meth)acrylate being more preferred.

Commercially available products of core-shell type graft copolymer particles include, for example, "CHT" manufactured by Cheil Textile Co., Ltd.; "B602" manufactured by UMGABS; "PARALOID EXL2602", "PARALOID EXL2603", "PARALOID EXL2655", "PARALOID EXL2311", "PARALOID EXL2313", "PARALOID EXL2315", "PARALOID KM330", "PARALOID KM336P", "PARALOID EXL336P" manufactured by Dow Chemical Japan Co., Ltd. "KCZ201" made by Mitsubishi Rayon; "MetablenC-223A", "MetablenE-901", "MetablenS-2001", "MetablenW-450A", "MetablenSRK-200" made by KANEKA; "Kaneace M-511", "Kaneace M-600", "Kaneace M-400", "Kaneace M-580", "Kaneace MR-01" made by KANEKA. These can be used alone or in combination of two or more types.

The average particle size (average primary particle size) of the core-shell graft copolymer particles is not particularly limited, but is preferably 20 nm or more, more preferably 50 nm or more, further preferably 80 nm or more, particularly preferably 100 nm or more, preferably 5,000 nm or less, further preferably 2,000 nm or less, further preferably 1,000 nm or less, and particularly preferably 500 nm or less. The average particle size (average primary particle size) of the core-shell graft copolymer particles can be measured using a Zeta potential particle size distribution measuring device or the like.

The content of the (C) organic filler is 5.0% by mass or more, based on 100% by mass of the non-volatile components in the resin composition. From the viewpoint of suppressing the adhesiveness as much as possible and further reducing the amount of the (B) inorganic filler as much as possible to obtain a hardened material with higher flexibility, the content is preferably 5.5% by mass or more, more preferably 5.8% by mass or more, further preferably 6.0% by mass or more, and particularly preferably 6.2% by mass or more. (C) The upper limit of the content of the organic filler is preferably 30% by mass or less, 20% by mass or less, and more preferably 15% by mass or less, from the viewpoint of controlling the viscosity as low as possible, with the non-volatile components in the resin composition being 100% by mass. From the viewpoint of reducing hole defects and achieving better pattern embedding properties, it is further preferably 10% by mass or less, and particularly preferably 8% by mass or less.

<(D) Adhesive softener> The resin composition of the present invention contains (D) an adhesive softener.

(D) Adhesive softening agent refers to a softening agent that imparts flexibility to a cured product of a thermosetting resin and has a property of improving the adhesiveness of the cured product. (D) Adhesive softening agent can be widely used conventional softening agents that have a property of improving the adhesiveness of a cured product. (D) Adhesive softening agent includes, but is not limited to, resins having a polybutadiene structure (hereinafter referred to as "polybutadiene resin"), polyrotaxane resins, polyimide resins, maleimide resins having a dimer acid skeleton, and the like.

The polybutadiene structure includes not only a structure formed by polymerization of butadiene but also a structure formed by hydrogenation of the structure. In addition, the butadiene structure may be partially or entirely hydrogenated. Furthermore, the polybutadiene structure may be contained in the main chain or in the side chain in the component (D).

Preferred examples of the polybutadiene resin include resins containing a hydrogenated polybutadiene skeleton, polybutadiene resins containing a hydroxyl group, polybutadiene resins containing a phenolic hydroxyl group, polybutadiene resins containing a carboxyl group, polybutadiene resins containing an acid anhydride group, polybutadiene resins containing an epoxy group, polybutadiene resins containing an isocyanate group, polybutadiene resins containing a urethane group, polyphenylene ether-polybutadiene resins, etc. Here, the "resin containing a hydrogenated polybutadiene skeleton" refers to a resin in which at least a portion of the polybutadiene skeleton is hydrogenated, and does not necessarily need to be a resin in which the polybutadiene skeleton is completely hydrogenated. Examples of the resin containing a hydrogenated polybutadiene skeleton include epoxy resins containing a hydrogenated polybutadiene skeleton, and examples of the polybutadiene resin containing a phenolic hydroxyl group include resins having a polybutadiene structure and a phenolic hydroxyl group.

Specific examples of the polybutadiene resin having a polybutadiene structure in the molecule include "BX360" and "BX660" (polyphenylene ether-polybutadiene resin) manufactured by Nippon Kayaku Co., Ltd., "Ricon 657" (epoxy-containing polybutadiene) manufactured by Cray Valley Co., Ltd., "Ricon 130MA8", "Ricon 130MA13", "Ricon 130MA20", "Ricon 131MA5", "Ricon 131MA10", "Ricon 131MA17", "Ricon 131MA20", "Ricon 131MA30", "Ricon 131MA40", "Ricon 131MA51", "Ricon 131MA10", "Ricon 131MA17", "Ricon 131MA20", "Ricon 131MA52", "Ricon 131MA11", "Ricon 131MA13", "Ricon 131MA17", "Ricon 131MA20", "Ricon 131MA53", "Ricon 131MA11", "Ricon 131MA13 ... 184MA6" (polybutadiene containing anhydride groups), "GQ-1000" (polybutadiene with hydroxyl and carboxyl groups introduced), "G-1000", "G-2000", "G-3000" (polybutadiene with hydroxyl groups at both ends), "GI-1000", "GI-2000", "GI-3000" (polybutadiene with hydroxyl groups at both ends), "PB3600" and "PB4700" made by Daicel (polybutadiene skeleton epoxy compounds), "EPFDA1005", "EPFDA1010", "EPFDA1020" (epoxy compounds of styrene, butadiene and styrene block copolymers), Nagase ChemteX The company's "FCA-061L" (hydrogenated polybutadiene skeleton epoxy compound), "R-45EPT" (polybutadiene skeleton epoxy compound), etc.

In addition, examples of preferred polybutadiene resins include linear polyimide butadiene resins (polyimides described in Japanese Patent Publication No. 2006-37083 and International Publication No. 2008/153208) using hydroxyl-terminated polybutadiene, diisocyanate compounds, and polyacids or their anhydrides as raw materials. The polyimide butadiene resin preferably contains 60% to 95% by weight, and more preferably 75% to 85% by weight of polybutadiene structures. For details of the polyimide butadiene resin, reference may be made to Japanese Patent Publication No. 2006-37083 and International Publication No. 2008/153208, the contents of which are incorporated herein by reference.

The number average molecular weight of the hydroxyl-terminated polybutadiene of the raw material of the polyimide butadiene resin is preferably 500 to 5,000, more preferably 1,000 to 3,000, from the viewpoint of exerting the desired effect of the present invention. The hydroxyl equivalent of the hydroxyl-terminated polybutadiene is preferably 250 to 1,250, from the viewpoint of exerting the desired effect of the present invention.

The diisocyanate compound as a raw material of the polyimide butadiene resin may be, for example, aromatic diisocyanates such as toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, etc.; aliphatic diisocyanates such as hexamethylene diisocyanate, etc.; alicyclic diisocyanates such as isophorone diisocyanate, etc. Among these, aromatic diisocyanates are preferred, and toluene-2,4-diisocyanate is more preferred.

Examples of the polybasic acid or its anhydride as a raw material of the polyimidobutadiene resin include ethylene glycol ditrimellitate, pyromellitic acid, benzophenonetetracarboxylic acid, biphenyltetracarboxylic acid, naphthalenetetracarboxylic acid, 5-(2,5-dioxytetrahydrofuranyl)-3-methyl-cyclohexene-1,2-dicarboxylic acid, 3,3'-4,4'-diphenylsulfonatetetracarboxylic acid and their anhydrides, tribasic acids such as trimellitic acid and cyclohexanetricarboxylic acid and their anhydrides, and 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxy-3-furanyl)-naphtho(1,2-C)furan-1,3-dione.

The polyrotaxane resin is a resin having a structure in which a plurality of cyclic molecules are covered with a linear chain-containing axle molecule in a manner that the cyclic molecules are passed through, and a sealing group that seals the end of the axle molecule to prevent the cyclic molecule from slipping off. The number of cyclic molecules in the polyrotaxane resin (covering amount) is not particularly limited within the range of the number of cyclic molecules being 2 or more. For example, when one axle molecule is covered with a plurality of cyclic molecules passing through, when the maximum coverage amount of cyclic molecules on one axle molecule (maximum coverage amount) is 100%, it is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more, and preferably 90% or less, more preferably 85% or less, and even more preferably 80% or less. The coating amount can be determined by the length of the axle molecule and the thickness of the ring molecule. For example, when the axle molecule is polyethylene glycol and the ring molecule is α-cyclodextrin, the maximum coating amount can be obtained experimentally (Macromolecules 1993, 26, 5698-5703 as a reference).

The spindle molecule in the polyrotaxane resin may be a linear chain molecule with a molecular weight of 10,000 or more and a terminal that can be chemically modified with a sealing group. "Linear chain" means that it is substantially a straight chain. If the ring molecule through which the spindle molecule passes can rotate or move, the spindle molecule may also have a branched chain. Examples of the chain molecule include polyvinyl alcohol, polyvinyl pyrrolidone, poly(meth)acrylic cellulose resins, polyacrylamide, polyethylene oxide, polyethylene glycol, polypropylene glycol, polyvinyl acetal resins, polyvinyl methyl ether, polyamine, polyethylene imine, casein, gelatin, starch, polyolefin, polyester, polyvinyl chloride, polystyrene, copolymers such as acrylonitrile-styrene copolymer, acrylic resin, polycarbonate, polyurethane, polyvinyl butyral, polyisobutylene, polytetrahydrofuran, polyamide, polyimide, polydienes, polysiloxanes, polyureas, polysulfides, polyphosphazenes, polyketones, polyphenylene esters, polyhalides and derivatives thereof. Among these, polyethylene glycol chains are preferably used. Two or more of these may be mixed in the polyrotaxane resin.

The length of the axle molecule is not particularly limited if the ring molecule can rotate or move. The length of the axle molecule can be expressed using the weight average molecular weight. The weight average molecular weight of the axle molecule is preferably 3,000 or more, more preferably 4,000 or more, and even more preferably 5,000 or more, and is preferably 100,000 or less, more preferably 90,000 or less, and even more preferably 85,000 or less. The weight average molecular weight of the axle molecule is a weight average molecular weight in terms of polystyrene measured by colloid permeation chromatography (GPC).

The axis molecule usually has a structure in which a molecule containing a sealing group reacts and is bonded to the above-mentioned functional group of a molecule having functional groups at both ends. Examples of the functional group include amide group, hydroxyl group, carboxyl group, acrylic group, methacrylic group, epoxy group, vinyl group, and the like.

The cyclic molecules in the polyrotaxane resin are cyclic molecules that can cover the axial molecules in a permeated state, and molecules having at least one reactive group (functional group) that can react with the (E) curing agent can be used. Cyclic molecules refer to molecules that are substantially cyclic, and "substantially cyclic" includes those that are not completely ring-closed, and also includes those that have one or more ends of the English "C" that are not bonded, and have a superimposed helical structure. Examples of cyclic molecules include cyclodextrins, crown ethers, cryptands, macrocyclic amines, calixarenes, cycloarenes, etc. Among these, cyclodextrins are preferred. Two or more of these can be mixed in the polyrotaxane resin.

Examples of cyclodextrins include α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, dimethylcyclodextrin, and glucosylcyclodextrin, and derivatives or modified forms thereof.

The cyclic molecule preferably contains a reactive group. Examples of the reactive group include hydroxyl, carboxyl, acrylic, methacrylic, epoxy, and vinyl groups, among which hydroxyl groups are preferred. Since the cyclic molecule has a reactive group, the cyclic molecules can be crosslinked with each other or the polyrotaxane resin can be crosslinked with the thermosetting resin through a curing agent. In addition, the reactive group of one cyclic molecule can be crosslinked with the reactive group of another cyclic molecule. The reactive group can be a single type or two or more types.

The reactive group may not be directly bonded to the cyclic molecule. For example, when the cyclic molecule is cyclodextrin, the hydroxyl group existing in the cyclodextrin itself is the reactive group. When a hydroxypropyl group is added to the hydroxyl group, the hydroxyl group of the hydroxypropyl group is also a reactive group. Furthermore, when the ring-opening polymerization of ε-caprolactone is carried out through the hydroxyl group of the hydroxypropyl group, when there is a caprolactone chain, the hydroxyl group at the end on the opposite side of the polyester part of the caprolactone chain is also a reactive group.

The reactive group of the cyclic molecule may be one, or two or more, per one cyclic molecule.

The weight average molecular weight of the cyclic molecule is preferably 5,000 or more, more preferably 6,000 or more, and even more preferably 7,000 or more, and is preferably 1,500,000 or less, more preferably 1,400,000 or less, and even more preferably 1,350,000 or less. The weight average molecular weight of the cyclic molecule is a weight average molecular weight in terms of polystyrene measured by colloid permeation chromatography (GPC).

The sealing group in the polyrotaxane resin is not particularly limited as long as it has a structure with a degree of swelling that prevents the ring molecule from falling off. Examples of the sealing group include cyclodextrin group, adamantyl group, dinitrophenyl group, trityl group, etc. Among them, adamantyl group is preferred. The polyrotaxane resin may contain only one type or two or more types.

The weight average molecular weight of the polyrotaxane resin as a whole is preferably 10,000 or more, more preferably 15,000 or more, and even more preferably 20,000 or more, and is preferably 1,500,000 or less, more preferably 1,400,000 or less, and even more preferably 1,350,000 or less. The weight average molecular weight of the polyrotaxane resin is a weight average molecular weight in terms of polystyrene measured by colloid permeation chromatography (GPC).

The hydroxyl value of the polyrotaxane resin is preferably 45 mgKOH/g or more, more preferably 50 mgKOH/g or more, and even more preferably 55 mgKOH/g or more, and is preferably 120 mgKOH/g or less, more preferably 115 mgKOH/g or less, and even more preferably 110 mgKOH/g or less. The hydroxyl value can be measured in accordance with JIS K0070.

The polyrotaxane resin may be in liquid form, but is preferably contained in the resin composition in the form of particles. The polyrotaxane resin in the form of particles is easy to disperse, and can further reduce the viscosity of the resin composition.

The average particle size of the particulate polyrotaxane resin is preferably 100 nm or more, more preferably 500 nm or more, and even more preferably 800 nm or more, and preferably 50,000 nm or less, more preferably 40,000 nm or less, and even more preferably 30,000 nm or less. The particulate polyrotaxane resin having such an average particle size is easy to be uniformly dispersed in the resin composition, and the viscosity of the resin composition is easy to reduce. The average particle size can be measured in the same way as the average particle size of the inorganic filler.

The polyrotaxane resin can be synthesized by the methods described in, for example, International Publication No. 01/83566, Japanese Patent Application No. 2005-154675, and Patent No. 4482633.

As the polyrotaxane resin, a commercially available product can be used. Examples of the commercially available product include "SH2400B-007", "SH1310P", and "SeRM Super Polymer A1000" manufactured by Advanced Softmaterials Inc. These may be used alone or in combination of two or more.

Polyimide resin is a resin having an imide bond in the repeating unit. Polyimide resin generally includes a resin obtained by imidization reaction of a diamine compound and tetracarboxylic anhydride. Polyimide resin also includes modified polyimide resins such as siloxane-modified polyimide resins.

The polyimide resin may comprise, for example, formula (1):

[wherein, ^X1 is a tetravalent group obtained by removing two -CO-O-CO- from a tetracarboxylic dianhydride, ^X2 is a divalent group obtained by removing two _-NH2 from a diamine compound, and n is an integer greater than or equal to 2].

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

The aliphatic diamine compound may 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, 1,10-diaminodecane, etc.; 1,2-diamino-2-methylpropane, 2,3-diamino-2, Branched chain aliphatic diamine compounds such as 3-butane, 2-methyl-1,5-diaminopentane, etc.; alicyclic diamine compounds such as 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), etc.; dimer acid type diamine (hereinafter referred to as "dimer diamine"), etc.

Dimer acid type diamine refers to a diamine compound obtained by replacing the two terminal carboxylic acid groups (-COOH) of dimer acid with aminomethyl groups (-CH ₂ -NH ₂ ) or amino groups (-NH ₂ ). Dimer acid is a known compound obtained by dimerizing unsaturated fatty acids (preferably those with 11 to 22 carbon atoms, and more preferably those with 18 carbon atoms), and its industrial production process is almost standardized in the industry. Dimer acid is easily available with a carbon number of 36 dimer acid obtained by dimerizing unsaturated fatty acids with 18 carbon atoms such as oleic acid and linolenic acid, which are particularly inexpensive and easily available, as a main component. 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, hydrogenated products whose unsaturation is reduced by further hydrogenation are also included in dimer acids. Dimer acid type diamines can be obtained as commercial products, for example, PRIAMINE 1073, PRIAMINE 1074, PRIAMINE 1075 manufactured by Kroda Japan, Versamine 551, Versamine 552 manufactured by Cognis Japan Ltd., etc.

Examples of the aromatic diamine compound include phenylenediamine compounds, naphthalenediamine compounds, and diphenylamine compounds.

The phenylenediamine compound refers to a compound composed of a benzene ring having two amino groups. Furthermore, the benzene ring may have 1 to 3 substituents. The substituents are not particularly limited. Specifically, the phenylenediamine compound includes 1,4-phenylenediamine, 1,2-phenylenediamine, 1,3-phenylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,5-diaminobiphenyl, 2,4,5,6-tetrafluoro-1,3-phenylenediamine, and the like.

The naphthalene diamine compound refers to a compound composed of a naphthalene ring having two amino groups. Furthermore, the naphthalene ring may have 1 to 3 substituents. The substituents are not particularly limited. Specifically, the naphthalene diamine compound includes 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, 2,6-diaminonaphthalene, 2,3-diaminonaphthalene, etc.

A diphenylamine compound refers to a compound containing two aniline structures in the molecule. Furthermore, the two benzene rings in the two aniline structures may each have 1 to 3 substituents. The substituents are not particularly limited. The two aniline structures in the diphenylamine compound may be directly bonded and/or bonded through 1 or 2 divalent linking groups having 1 to 100 (preferably 1 to 50, more preferably 1 to 20) backbone atoms selected from carbon atoms, oxygen atoms, sulfur atoms and nitrogen atoms. The diphenylamine compound also includes two aniline structures bonded at two locations.

Specific examples of the "divalent linking group" in the diphenylamine compound include -NHCO-, -CONH-, -OCO-, -COO-, -CH2-, -CH2CH2-, -CH2CH2CH2- _{, -CH2CH2CH2CH2-} , -CH2CH2CH2CH2CH2- _, -CH2CH2CH2CH2CH2-, -CH ₍ CH3) _- , -C(CH3) _2- , -C _{( CF3 ) 2- ,} -CH ₌ CH-, -O-, _-S-, -CO-, _{-SO2- , -NH- ,} -Ph- _, -Ph- _{Ph- ,} -C( _CH3 ) ₂ -Ph-C( _CH3 ) _2- , -O-Ph _- O-, -O-Ph-Ph-O-, -O _- Ph-SO2 -Ph-O-, -O-Ph-C(CH ₃ ) ₂ -Ph-O-, -C(CH ₃ ) ₂ -Ph-C(CH ₃ ) ₂ -.

(In the formula, * is the bonding site.) etc. "Ph" is 1,4-phenylene, 1,3-phenylene or 1,2-phenylene.

Specific examples of the diphenylamine compound include 4,4'-diamino-2,2'-ditrifluoromethyl-1,1'-biphenyl, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 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'-(hexafluoroisopropylidene)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-fluorenyl)diphenylamine, 2,2-bis(3-methyl-4-aminophenyl)propane, 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)propane phenyl)fluorene, 5-(4-aminophenoxy)-3-[4-(4-aminophenoxy)phenyl]-1,1,3-trimethylindan, 4-aminobenzoic acid 5-amino-1,1'-biphenyl-2-yl, etc., preferably 5-(4-aminophenoxy)-3-[4-(4-aminophenoxy)phenyl]-1,1,3-trimethylindan, and 4-aminobenzoic acid 5-amino-1,1'-biphenyl-2-yl.

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

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

Examples of the aromatic tetracarboxylic dianhydride include benzenetetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, anthracenetetracarboxylic dianhydride, and diphthalic dianhydride, and diphthalic dianhydride is preferred.

Phenolic dianhydride refers to a dianhydride of benzene having four carboxyl groups. Furthermore, the benzene ring may have 1 to 3 substituents. The substituents are not particularly limited. Specific examples of phenylene tetracarboxylic dianhydride include pyromellitic dianhydride and 1,2,3,4-benzenetetracarboxylic dianhydride.

Naphthalenetetracarboxylic dianhydride refers to a dianhydride of naphthalene having four carboxyl groups. Furthermore, the naphthalene ring may have 1 to 3 substituents. The substituents are not particularly limited. Specifically, naphthalenetetracarboxylic dianhydride includes 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, and the like.

Anthracenetetracarboxylic dianhydride refers to an anthracene dianhydride having four carboxyl groups. Furthermore, the anthracene ring may have 1 to 3 substituents. The substituents are not particularly limited. Specifically, anthracenetetracarboxylic dianhydride includes 2,3,6,7-anthracenetetracarboxylic dianhydride.

Diphthalic anhydride refers to a compound containing two phthalic anhydrides in the molecule. Furthermore, the two benzene rings in the two phthalic anhydrides may each have 1 to 3 substituents. The substituents are not particularly limited. The two phthalic anhydrides in diphthalic anhydride may be directly bonded or bonded through a divalent linking group having 1 to 100 (preferably 1 to 50, more preferably 1 to 20) skeleton atoms selected from carbon atoms, oxygen atoms, sulfur atoms and nitrogen atoms.

_Specific examples of the divalent linking _group include _{-CH2- , -CH2CH2-} , -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, -CH ₍ CH3) _{-, -C(CH3)2- , -O- ,} -CO-, -SO2-, _-Ph- , -O _- Ph _{- O- ,} -O _- Ph _- SO2-Ph-O-, and -O-Ph-C( _{CH3 ) 2 -} Ph-O- _.

The diphthalic acid dianhydride may be, for example, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic acid dianhydride, 3,3',4,4'-diphenyl sulfone tetracarboxylic acid dianhydride, 3,3',4,4'-biphenyl tetracarboxylic acid dianhydride, 2,2',3,3'-biphenyl tetracarboxylic acid dianhydride, 2,3,3',4'-biphenyl tetracarboxylic acid dianhydride, Dianhydride, 2,3,3',4'-benzophenone tetracarboxylic dianhydride, 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, 2,3,3',4'-diphenylsulfonate tetracarboxylic dianhydride, 2,2'-bis(3,4-dicarboxyphenoxyphenyl)sulfonate dianhydride, methylene-4,4'-diphthalic dianhydride, 1,1-ethylene-4,4'-diphthalic dianhydride, 2,2- Propylene-4,4'-diphthalic anhydride, 1,2-ethylene-4,4'-diphthalic anhydride, 1,3-trimethylene-4,4'-diphthalic anhydride, 1,4-tetramethylene-4,4'-diphthalic anhydride, 1,5-pentamethylene-4,4'-diphthalic anhydride, 1,3-bis(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'-isopropylenediphenoxy)bisphthalic anhydride, etc.

Aliphatic tetracarboxylic dianhydrides include, for example, 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'-biscyclohexyltetracarboxylic dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene- 4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,2-ethylene-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.

As tetracarboxylic dianhydride, commercially available ones may be used, or those synthesized by a known method or a method based thereon 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 is preferably 10 mol% or more, more preferably 30 mol% or more, further preferably 50 mol% or more, even more preferably 70 mol% or more, even more preferably 90 mol% or more, and particularly preferably 100 mol%.

The weight average molecular weight of the polyimide resin is preferably 1,000 to 100,000.

The maleimide resin having a dimer acid skeleton is, for example, a bismaleimide compound having a hydrocarbon skeleton derived from dimer acid. The maleimide resin having a dimer acid skeleton is, for example, a bismaleimide compound obtained by subjecting at least a dimer acid type diamine to an imidization reaction with maleic anhydride, and further includes a bismaleimide compound obtained by subjecting a dimer acid type diamine to an imidization reaction with tetracarboxylic dianhydride and maleic anhydride.

The maleimide resin having a dimer acid skeleton is, for example, of the following formula (2):

[In the formula, ^Y1 and ^Y3 are each independently a divalent group obtained by removing two _-NH2 from a dimer acid type diamine, ^Y2 is a tetravalent group obtained by removing two -CO-O-CO- from a tetracarboxylic dianhydride, and m is 0 or 1.] A bismaleimide compound represented by.

Specific examples of maleimide resins having a dimer acid skeleton include "BMI689", "BMI1500", "BMI1700", and "BMI3000" manufactured by DESIGNER MOLECULES. These may be used alone or in combination of two or more.

(D) The content of the adhesive softening agent is not particularly limited, but from the viewpoint of obtaining a cured product with better flexibility, when the non-volatile components in the resin composition are 100% by mass, it is preferably 1% by mass or more, more preferably 5% by mass or more, further preferably 10% by mass or more, and particularly preferably 15% by mass or more. (D) The upper limit of the content of the adhesive softening agent is not particularly limited, but when the non-volatile components in the resin composition are 100% by mass, it 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.

<(E) Hardener> The resin composition of the present invention may contain (E) hardener as an optional component. (E) Hardener has the function of hardening (A) thermosetting resin.

(E) The hardener is not particularly limited. When the thermosetting resin (A) is an epoxy resin, examples thereof include phenol hardeners, naphthol hardeners, acid anhydride hardeners, active ester hardeners, benzoxazine hardeners, cyanate ester hardeners, carbodiimide hardeners, phenol hardeners, naphthol hardeners, and active ester hardeners. (E) The hardener preferably contains an active ester hardener. The hardener may be used alone or in combination of two or more.

Phenol-based hardeners and naphthol-based hardeners are preferably phenol-based hardeners having a novolac structure or naphthol-based hardeners having a novolac structure from the viewpoint of heat resistance and water resistance. Furthermore, nitrogen-containing phenol-based hardeners or nitrogen-containing naphthol-based hardeners are preferred from the viewpoint of adhesion to the object to be coated, and phenol-based hardeners containing a triazine skeleton or naphthol-based hardeners containing a triazine skeleton are more preferred. Among them, phenol novolac resins containing a triazine skeleton are preferred from the viewpoint of heat resistance, water resistance, and highly satisfactory adhesion. Specific examples of phenol-based hardeners and naphthol-based hardeners include "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Meiwa Chemicals, "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 & Sumitomo Chemicals Corporation, 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. 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-dihydroxytetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, anhydrous trimellitic acid, pyromellitic dianhydride, diphenyl Ketone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenylsulfonate tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxy-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bis(dehydrated trimellitate), styrene-maleic acid resin obtained by copolymerization of styrene and maleic acid, and other polymer anhydrides. Examples of commercially available anhydride hardeners include "HNA-100" and "MH-700" manufactured by Shin Nippon Chemical Co., Ltd.

Although the active ester curing agent is not particularly limited, it is generally 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 perspective 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 phenolic compound or naphthol compound include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, acid phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucinol, benzenetriol, dicyclopentadiene-type diphenolic compounds, phenol novolac, etc. Here, "dicyclopentadiene-type diphenolic compounds" refer to diphenolic compounds obtained by condensing one molecule of dicyclopentadiene with two molecules of phenol.

Specifically, active ester compounds containing dicyclopentadiene diphenol structures, active ester compounds containing naphthalene structures, active ester compounds containing acetylated products of phenol novolacs, and active ester compounds containing benzoylated products of phenol novolacs are preferred, among which active ester compounds containing naphthalene structures and active ester compounds containing dicyclopentadiene diphenol structures are more preferred. "Dicyclopentadiene diphenol structures" refer to divalent structural units composed of phenylene-dicyclopentadiene-phenylene.

Commercially available products of active ester curing agents include, for example, "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) as active ester compounds containing a dicyclopentadiene-type diphenol structure; and "EXB9416-70BK", "EXB-8150-65T" (manufactured by DIC Corporation). Examples of the active ester compound of the acetylated product of phenol novolac include "DC808" (manufactured by Mitsubishi Chemical Corporation); examples of the active ester compound of the benzoylated product of phenol novolac include "YLH1026" (manufactured by Mitsubishi Chemical Corporation); examples of the active ester curing agent of the acetylated product of phenol novolac include "DC808" (manufactured by Mitsubishi Chemical Corporation); examples of the active ester curing agent of the benzoylated product of phenol novolac include "YLH1026" (manufactured by Mitsubishi Chemical Corporation), "YLH1030" (manufactured by Mitsubishi Chemical Corporation), and "YLH1048" (manufactured by Mitsubishi Chemical Corporation); etc.

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

Cyanate ester curing agents include, for example, 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-cyanatephenylmethane) ), 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 derived from phenol novolac and cresol novolac, and prepolymers of these cyanate resins partially triazinated. Specific examples of cyanate ester curing agents include "PT30" and "PT60" manufactured by Lonza Japan (both are polyfunctional cyanate ester resins of phenol novolac type), "BA230", "BA230S75" (prepolymers of bisphenol A dicyanate partially or completely triazinated to become trimer), etc.

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

When the resin composition contains (E) a hardener, the amount ratio of (A) a thermosetting resin to (E) a hardener is preferably in the range of 1:0.2 to 1:2, more preferably 1:0.3 to 1:1.5, and even more preferably 1:0.4 to 1:1.2, in terms of [the total number of reactive groups of the thermosetting resin]:[the total number of reactive groups of the hardener]. Here, the reactive group of the hardener refers to an active hydroxyl group, an active ester group, etc., which varies depending on the type of the hardener. The reactive group of the thermosetting resin refers to an epoxy group, etc., which varies depending on the type of the thermosetting resin.

When the resin composition contains (E) a hardener, the content thereof is not particularly limited, but when the non-volatile components in the resin composition are 100% by mass, it is preferably 0.1% by mass or more, more preferably 1% by mass or more, further preferably 3% by mass or more, and particularly preferably 4% by mass or more. The upper limit of the content of the (E) hardener is not particularly limited, but when the non-volatile components in the resin composition are 100% by mass, it 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.

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

(F) The curing accelerator is not particularly limited. When the (A) thermosetting resin is an epoxy resin, examples thereof include phosphorus-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 amine-based curing accelerators are more preferred. The curing accelerator may be used alone or in combination of two or more.

Phosphorus-based hardening accelerators include, for example, triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate.

Amine-based hardening accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine (DMAP), benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5,4,0)-undecene, etc., with 4-dimethylaminopyridine being preferred.

Imidazole hardening accelerators include, for example, 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, 1-cyanoethyl-2-phenylimidazole, 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 isocyanuric acid adduct Imidazole compounds such as cyanuric acid adducts, 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-methylimidazoline, 2-phenylimidazoline, and adducts of imidazole compounds with epoxy resins.

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

Examples of the guanidine-based hardening accelerator include dicyandiamide, 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 the organic metal complex include organic cobalt complexes such as cobalt (II) acetylacetylacetonate and cobalt (III) acetylacetylacetonate, organic copper complexes such as copper (II) acetylacetylacetonate, organic zinc complexes such as zinc (II) acetylacetylacetonate, organic iron complexes such as iron (III) acetylacetylacetonate, organic nickel complexes such as nickel (II) acetylacetylacetonate, and organic manganese complexes such as manganese (II) acetylacetylacetonate. 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 (F) a hardening accelerator, the content thereof is not particularly limited, but when the non-volatile components in the resin composition are 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 (F) hardening accelerator is not particularly limited, but when the non-volatile components in the resin composition are 100% by mass, it is preferably 2% by mass or less, more preferably 1% by mass or less, further preferably 0.5% by mass or less, and particularly preferably 0.3% by mass or less.

<(G) Other additives> The resin composition of the present invention may contain any additives as a non-volatile component. Examples of such additives include thermoplastic resins such as phenoxy resins, polyvinyl acetal resins, polyolefin resins, polysulfide resins, polyethersulfide resins, polyphenylene ether resins, polycarbonate resins, polyetheretherketone resins, polyester resins, etc.; organic metal compounds such as organic copper compounds, organic zinc compounds, and organic cobalt compounds; colorants such as phthalocyanine blue, copper phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, and carbon black; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and thiodiphenylamine; leveling agents such as siloxane; and thickeners such as Bentonite and montmorillonite. Defoaming agents such as silicone defoamers, acrylic defoamers, fluorine defoamers, and vinyl resin defoamers; UV absorbers such as benzotriazole UV absorbers; adhesion enhancers such as urea silane; adhesion enhancers such as silane coupling agents, triazole adhesion enhancers, tetrazolyl adhesion enhancers, and triazine adhesion enhancers; antioxidants such as hindered phenol antioxidants and hindered amine antioxidants; fluorescent brighteners such as stilbene derivatives; phosphorus flame retardants (such as phosphate compounds, diphosphine compounds, phosphine, etc.); (G) The content of other additives can be appropriately set by the manufacturer.

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

(H) The content of the organic solvent may be preferably set to 30% by mass or more, more preferably 35% by mass or more, further preferably 40% by mass or more, and particularly preferably 45% by mass or more, in terms of efficient drying of the resin composition, as the mass ratio of the non-volatile components to the total mass of the resin composition, i.e., the solid fraction. The upper limit of the solid fraction is not particularly limited, but may be preferably 100% by mass or less, more preferably 95% by mass or less, further preferably 92% by mass or less, and particularly preferably 90% by mass or less, in terms of the operability of the resin composition.

<Manufacturing method of resin composition> The resin composition of the present invention can be manufactured by, for example, adding (A) thermosetting resin, (B) inorganic filler, (C) organic filler, (D) adhesive softener, (E) hardener if necessary, (F) hardening accelerator if necessary, (G) other additives if necessary, and (H) organic solvent if necessary in any reaction container in any order and/or partially or all at the same time, and then mixing. In addition, in the process of adding each component for mixing, 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 each component for mixing, stirring or shaking can be performed. Furthermore, during or after the addition and mixing, the resin composition may be stirred using a stirring device such as a mixer to be uniformly dispersed.

<Characteristics of the resin composition> The resin composition of the present invention contains (A) a thermosetting resin, (D) an adhesive softener, and (B) an inorganic filler, and contains more than 5% by mass of (C) an organic filler, which can maintain excellent flexibility while suppressing adhesiveness.

The resin composition of the present invention has sufficient flexibility because it contains (D) an adhesive softening agent. For example, 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 is subjected to an MIT folding resistance test in accordance with JIS C-5016 with 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 is preferably 3,000 times or more, more preferably 5,000 times or more, further preferably 7,000 times or more, and particularly preferably 8,000 times or more.

The resin composition of the present invention, for example, has a minimum melt viscosity of 40,000 poise or less, preferably 30,000 poise or less, preferably 20,000 poise or less, and preferably 10,000 poise or less, when measured under the conditions of a starting temperature of 60°C to 200°C, a heating rate of 5°C/min, a vibration rate of 1 Hz, and a strain of 1 degree.

Since the resin composition of the present invention contains (C) an organic filler, for example, the layered resin composition has an adhesive force of preferably 2.0 N or less, more preferably 1.8 N or less, further preferably 1.7 N or less, and particularly preferably 1.6 N or less when measured using a probe viscosity tester under the conditions of a probe of 5 mm diameter, a load of 1 kgf/cm ² , a contact speed of 0.5 mm/sec, a tensile speed of 0.5 mm/sec, a retention time of 10 sec, and a temperature of 80°C.

In addition, the resin composition of the present invention, especially when the content of the organic filler (C) is 10 mass % or less, has the characteristics of suppressing hole defects and improving pattern embedding properties.

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

The support may be, for example, a film made of plastic material, a metal foil, or a release paper, with a film made of plastic material or a metal foil being preferred.

When a film made of a plastic material is used as the support, the plastic material may be polyesters such as polyethylene terephthalate (hereinafter referred to as "PET") and polyethylene naphthalate (hereinafter referred to as "PEN"), polycarbonate (hereinafter referred to as "PC"), acrylic esters 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 the support, the metal foil may be, for example, copper foil, aluminum foil, etc., with copper foil being preferred. The copper foil may be a foil made of copper alone, or a foil made of an alloy of copper and other metals (such as tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.).

The surface of the support that is bonded to the resin composition layer may be subjected to a matte treatment, a corona treatment, or an antistatic treatment.

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. The release agent used for the release layer of the support with a release layer can be, for example, one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. The support with a release layer may 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, such as "SK-1", "AL-5", and "AL-7" manufactured by Lintec, "Lumina T60" manufactured by Toray Industries, "Purex" manufactured by Teijin, and "Unipeel" manufactured by UNITIKA LTD.

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 as necessary. The other layers may be, for example, a protective film corresponding to the support provided on the surface of the resin composition layer that is not bonded to the support (i.e., the surface opposite to the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating the protective film, dust adhesion to the surface of the resin composition layer or scratches can be suppressed.

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

The organic solvents that can be used when coating on the support include, for example, the same ones as those listed in the description of the above (H) organic solvents. The organic solvents may be used alone or in combination of two or more.

Drying can be carried out by known methods such as heating and blowing hot air. Although the drying conditions are not particularly limited, the content of the organic solvent in the resin composition layer is made to be 10 mass% or less, preferably 5 mass% or less, and then dried. It depends on the boiling point of the organic solvent in the resin composition or resin paint, but for example, when a resin composition or resin paint 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 sheets are sheets produced by laminating and curing multiple resin composition layers. Laminated sheets contain multiple insulating layers that are cured resin composition layers. 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, and particularly preferably 5 or more, preferably 20 or less, more preferably 15 or less, and particularly preferably 10 or less.

The laminated sheet is a sheet that is used with one side of the sheet bent. 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, 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 laminated sheet. The holes may be used as vias or through holes in the multi-layer flexible substrate.

The laminate sheet may contain any other elements besides the insulating layer. For example, the laminate sheet may have a conductive layer as an arbitrary element. The conductive layer is usually partially formed on the surface of the insulating layer or between the insulating layers. The 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. The alloy may be, 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). 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 may be a composite structure including two or more single metal layers or alloy layers composed of 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 to serve 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, and 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 to laminate and harden multiple resin composition layers. The lamination and hardening order of the resin composition layers is arbitrary as long as the desired laminated sheet can be obtained. For example, after laminating all the multiple resin composition layers, the laminated multiple resin composition layers can be hardened at once. In addition, for example, each time a different resin composition layer is laminated on a certain resin composition layer, the laminated resin composition layer can be hardened.

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

In a preferred embodiment, step (b) includes (II) hardening the first resin composition layer to form a first insulating layer, (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 any of the following steps, if necessary: (I) laminating a first resin composition layer on a thin sheet support substrate, (III) opening holes in the first insulating layer, (IV) roughening the first insulating layer, and (V) forming a conductor layer on the first insulating layer. 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, and a member in the form of a plate, a sheet or a film can be used.

The lamination of the sheet support substrate and the first resin composition layer can be performed by vacuum lamination. In the vacuum lamination, the hot 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 hot 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 hot 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 26.7hPa or less.

Lamination can be performed by a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum press laminator manufactured by Meiki Seisakusho Co., Ltd., a vacuum applicator manufactured by Nikko-Materials Co., Ltd., and a batch vacuum press laminator.

When a resin sheet is used, the sheet support substrate and the first resin component layer can be laminated by, for example, pressing the resin sheet from the support side so that the first resin component layer of the resin sheet is hot-pressed against the sheet support substrate. The member for hot-pressing the resin sheet against the sheet support substrate (hereinafter referred to as "hot-pressing member") may be, for example, a heated metal plate (SUS mirror plate, etc.) or a metal roller (SUS roller). It is preferred that the hot-pressing member is not pressed directly against the resin sheet, but is pressed through an elastic material such as heat-resistant rubber so that the first resin component layer fully follows the surface irregularities of the sheet support substrate.

After lamination, the first resin component layer can be smoothed by pressing, for example, with a hot press member under normal pressure (atmospheric pressure). 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 hot press member from the support side. The pressing conditions for the smoothing treatment can be the same as the hot pressing conditions for the above-mentioned lamination. The smoothing treatment can be performed by a commercially available press machine. The lamination and smoothing treatment can be performed continuously using the above-mentioned commercially available vacuum press machine.

Step (II) is a step of curing the first resin composition layer to form a first insulating layer. The heat 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 used.

Generally, 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. In addition, 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-cured, the first resin composition layer may be pre-heated at a temperature lower than the curing temperature. For example, before the first resin composition layer is heat-cured, the first resin composition layer may be pre-heated at a temperature of 50°C or higher but less than 120°C (preferably 60°C or higher but less than 115°C, more preferably 70°C or higher but less than 110°C) 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 opening a hole in the first insulating layer. Through step (III), a hole such as an interlayer hole or a through hole can be formed in the first insulating layer. The hole opening can be performed using a drill, laser, plasma, etc. according to 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 performing a roughening treatment on the first insulating layer. Usually, in step (IV), desmearing is also performed. Therefore, the roughening treatment is also called desmearing treatment. Examples of the roughening treatment include a method of sequentially performing an expansion treatment with an expansion fluid, a roughening treatment with an oxidizing agent, and a neutralization treatment with a neutralizing fluid.

The swelling liquid is not particularly limited, and examples thereof 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 can be 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 appropriately suppressing the expansion of the resin of the insulating layer, it is preferred to immerse the insulating layer in the swelling liquid at 40 to 80°C for 5 to 15 minutes.

Although the oxidizing agent is not particularly limited, an example thereof is an alkaline permanganic acid solution 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 %. Commercially available oxidizing agents include alkaline permanganic acid solutions such as "concentrate compact P", "concentrate compact CP", and "dosing solution Securigans P" manufactured by Atotech Japan. The roughening treatment with the oxidizing agent can be performed by immersing the hardened body in the oxidizing agent solution heated to 60°C to 80°C for 10 minutes to 30 minutes.

In addition, an acidic aqueous solution can be used as the neutralizing solution. A commercially available product is, for example, "Reduction Solution Securigant P" manufactured by Atotech Japan. The treatment with the neutralizing solution can be carried out by immersing the hardened body in a neutralizing solution at 30°C to 80°C for 5 to 30 minutes. In terms of workability, etc., it is preferred to immerse the hardened body in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes.

The arithmetic average 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. The lower limit is not particularly limited, but 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 as necessary. The conductive layer can be formed by, for example, plating, sputtering, evaporation, etc., of which plating is preferred. A suitable example is a method of plating on the surface of the first insulating layer by a suitable method such as a semi-additive method or a full-additive method to form a conductive layer having a desired wiring pattern. From the perspective of manufacturing simplicity, the semi-additive method is preferred.

The following is an example of forming a conductive layer by a semi-additive method. First, a deposited seed layer is formed on the surface of the first insulating layer by electroless plating. Next, a mask pattern is formed on the formed deposited seed layer to expose a portion of the deposited seed layer corresponding to the desired wiring pattern. After a metal layer is formed on the exposed deposited seed layer by electrolytic plating, the mask pattern is removed. Thereafter, the unnecessary deposited seed layer is removed by etching or the like, and a conductive layer having the desired wiring pattern can be formed.

After obtaining the first insulating layer in step (II), step (III), step (IV), and step (V) are performed as necessary, and then step (VI) is performed. 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 performed in the same manner as the lamination of the thin 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 plurality of insulating layers including a first insulating layer and a second insulating layer can be obtained.

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

In the above-mentioned embodiment, the embodiment of manufacturing a laminated sheet by laminating and curing two resin composition layers, namely the first resin composition layer and the second resin composition layer, is described. However, the laminated sheet may be manufactured by laminating and curing three or more resin composition layers. For example, in the method of the above-mentioned embodiment, the laminating and curing of the resin composition layers of steps (VI) to (VII) and, if necessary, the opening of holes in the insulating layer, the roughening treatment of the insulating layer, and the formation of a conductive layer on the insulating layer of steps (VIII) to (X) may be repeated to manufacture the 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 also be performed.

<Multi-layer flexible substrate> The multi-layer flexible substrate includes a laminate sheet. The multi-layer flexible substrate may contain only the laminate sheet, or may be combined with the laminate sheet and contain any components. The arbitrary components may include electronic components, cover film, etc.

The multi-layer flexible substrate can be manufactured by a manufacturing method including the method of manufacturing the above-mentioned laminated sheet. Therefore, the multi-layer 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 layers of a resin composition using the resin sheet.

The method for manufacturing a multi-layer flexible substrate may include any additional steps in combination with the aforementioned steps. For example, the method for manufacturing a multi-layer flexible substrate having electronic components may include the step of bonding the electronic components to a laminate sheet. The bonding conditions between the laminate sheet and the electronic components may be any conditions under which the terminal electrodes of the electronic components and the conductor layer as the wiring provided on the laminate sheet can be conductively connected. Furthermore, for example, the method for manufacturing a multi-layer flexible substrate having a covering film may include the step of laminating the laminate sheet and the covering film.

The aforementioned multi-layer flexible substrate can be used by bending one side of the laminated sheet included in the multi-layer flexible substrate toward each other. For example, the multi-layer flexible substrate is stored in a housing of a semiconductor device in a state where the multi-layer flexible substrate is bent to reduce the size. In addition, for example, in a semiconductor device having a bendable movable part, the multi-layer flexible substrate is provided on the movable part.

<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 many semiconductor devices, the multi-layer flexible substrate has a laminated sheet included in the multi-layer flexible substrate whose one side is bent toward each other so as to be accommodated in the outer casing of the semiconductor device.

Semiconductor devices include, for example, various semiconductor devices for electrical products (such as computers, mobile phones, digital cameras, and televisions) and vehicles (such as motorcycles, cars, trains, ships, and airplanes).

The semiconductor device can be manufactured by a manufacturing method including the steps of preparing a multi-layer flexible substrate, bending the multi-layer flexible substrate so that one side of the laminated sheet faces the other, and housing the bent multi-layer flexible substrate in a housing.

[Example]

The present invention is specifically described below with examples. However, the present invention is not limited to the following examples. In the following description, "parts" and "%" representing the amount refer to "parts by mass" and "% by mass" respectively unless otherwise specified. In addition, the operations described below are performed at room temperature and pressure unless otherwise specified.

<Synthesis Example 1: Synthesis of polybutadiene resin containing phenolic hydroxyl group> In a reaction container, 69g of bifunctional hydroxyl-terminated polybutadiene ("G-3000" manufactured by Nippon Soda Co., Ltd., number average molecular weight = 3000, hydroxyl equivalent = 1800g/eq.), 40g of aromatic hydrocarbon mixed solvent ("Ipzole 150" manufactured by Idemitsu Petrochemical Co., Ltd.), and 0.005g of dibutyltin laurate were placed, mixed and dissolved uniformly. After uniformization, the temperature was raised to 60°C, and 8g of isophorone diisocyanate ("IPDI" manufactured by Evonik Degussa Japan Co., Ltd., isocyanate equivalent = 113g/eq.) was added while stirring, and the reaction was carried out for about 3 hours.

Then, add 23 g of cresol novolac resin ("KA-1160" manufactured by DIC Corporation, hydroxyl equivalent = 117 g/eq.) and 60 g of ethyl diglycol acetate (manufactured by Daicel Corporation) to the reactant, raise the temperature to 150°C while stirring, and react for about 10 hours. Confirm the disappearance of the NCO peak at 2250 cm-1 by FT-IR. The disappearance of the NCO peak is regarded as the end point of the reaction, and the reactant is cooled to room temperature. Then, filter the reactant with a 100 mesh filter cloth to obtain an elastomer having a butadiene structure and phenolic hydroxyl groups (polybutadiene resin containing phenolic hydroxyl groups: non-volatile components 50% by mass). The number average molecular weight of the elastomer is 5900 and the glass transition temperature is -7°C.

<Synthesis Example 2: Synthesis of Polyimide Resin 1> 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, and imidization reaction was carried out for 4 hours at 180°C in a nitrogen atmosphere while toluene was removed from the system, thereby obtaining a polyimide solution containing polyimide resin 1 (non-volatile matter 20 mass %). In the polyimide solution, no precipitation of the synthesized polyimide resin 1 was observed.

<Synthesis Example 3: Synthesis of Polyimide Resin 2> 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 Kroda Japan) and 5.4 g of 1,3-bis(aminomethyl)cyclohexane were dropped, and an imidization reaction was carried out at 140°C for 1 hour. Thus, a polyimide solution (non-volatile matter: 30% by mass) containing polyimide resin 2 was obtained. The weight average molecular weight of polyimide resin 2 was 25,000.

<Synthesis Example 4: Synthesis of Polyimide Resin 3> A 500 mL detachable flask equipped with a water quantitative receiver connected to a reflux cooler, a nitrogen inlet pipe, 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-trimethylindane were added to the flask, and stirred at 45°C for 2 hours under a nitrogen flow to carry out a reaction. Then, the reaction solution was heated to about 160°C, and the condensed water was removed azeotropically with toluene under a nitrogen flow. Confirm that the water quantitative receiver accumulates the specified amount of water and that no water is seen to flow out. After confirmation, the reaction solution is heated again and stirred at 200°C for 1 hour. Thereafter, after cooling, a polyimide solution containing polyimide resin 3 (non-volatile matter 20 mass %) is obtained. The obtained polyimide resin 3 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 3 is 12,000.

<Example 1> 5 parts of bis(xylenol) epoxy resin ("YX4000HK" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight about 185 g/eq.), 5 parts of naphthalene epoxy resin ("ESN475V" manufactured by Nippon Steel & Sumikin Chemical Corporation, epoxy equivalent weight about 332 g/eq.), 5 parts of bisphenol AF epoxy resin ("YL7760" manufactured by Mitsubishi Chemical Corporation), and 1,1-diol-1-ylidene ether epoxy resin ("1-diol-1-ylidene ether epoxy resin" manufactured by Mitsubishi Chemical Corporation) were added. A mixed solvent of 10 parts of cyclohexane-type epoxy resin ("ZX1658GS" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent of about 135 g/eq.), 40 parts of the phenolic hydroxyl-containing polybutadiene resin obtained in Synthesis Example 1 (non-volatile component 50 mass %), and 10 parts of cyclohexanone was added and dissolved by heating while stirring. After cooling to room temperature, 4 parts of a cresol novolac hardener containing a triazine skeleton ("LA-3018-50P" manufactured by DIC, a hydroxyl equivalent of about 151, a 2-methoxypropanol solution containing 50% of non-volatile matter), 6 parts of an active ester hardener ("EXB-8000L-65M" manufactured by DIC, an active group equivalent of about 220, a MEK solution containing 65% of non-volatile matter by mass), and spherical silica ("SC2500SQ" manufactured by Admatex, an average particle size of 0.5 μm, a specific surface area of 11.2 ^m2) were mixed therein. /g, 40 parts of silica (surface treated with 1 part of N-phenyl-3-aminopropyltrimethoxysilane (KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.), 6 parts of core-shell graft copolymer rubber particles (EXL2655, manufactured by Dow Chemical Japan Co., Ltd.), 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.

<Example 2> The same operation as in Example 1 was performed to prepare a resin composition except that 100 parts of the polyimide solution (non-volatile component 20% by mass) obtained in Synthesis Example 2 was used instead of 40 parts of the phenolic hydroxyl-containing polybutadiene resin (non-volatile component 50% by mass) obtained in Synthesis Example 1.

<Example 3> The same operation as in Example 1 was performed to prepare a resin composition except that 66.7 parts of the polyimide solution (non-volatile component 30% by mass) obtained in Synthesis Example 3 was used instead of 40 parts of the phenolic hydroxyl-containing polybutadiene resin (non-volatile component 50% by mass) obtained in Synthesis Example 1.

<Example 4> The same operation as in Example 1 was performed to prepare a resin composition except that 100 parts of the polyimide solution (non-volatile component 20% by mass) obtained in Synthesis Example 4 was used instead of 40 parts of the phenolic hydroxyl-containing polybutadiene resin (non-volatile component 50% by mass) obtained in Synthesis Example 1.

<Example 5> The same operation as in Example 1 was performed to prepare a resin composition except that 40 parts of a resin containing a polybutadiene structure ("BX360", manufactured by Nippon Kayaku Co., Ltd., a block copolymer of polyphenylene ether and polybutadiene, a toluene solution containing 50% by mass of non-volatile components) was used instead of 40 parts of the polybutadiene resin containing a phenolic hydroxyl group (50% by mass of non-volatile components) obtained in Synthesis Example 1.

<Example 6> The same operation as in Example 1 was performed to prepare a resin composition except that 20 parts of bismaleimide resin ("BMI689" manufactured by DM Co., Ltd.) was used instead of 40 parts of the phenolic hydroxyl-containing polybutadiene resin (non-volatile component 50% by mass) obtained in Synthesis Example 1.

<Example 7> The same operation as in Example 1 was performed to prepare a resin composition except that 50 parts of a polyrotaxane resin (a 40% solution of methyl ethyl ketone of "SH1310P" manufactured by Advanced Softmaterials Inc., in which the axial molecules consist of polyethylene glycol chains and the cyclic molecules consist of cyclodextrins) was used instead of 40 parts of the phenolic hydroxyl-containing polybutadiene resin (non-volatile components 50% by mass) obtained in Synthesis Example 1.

<Example 8> Except that the amount of the core-shell graft copolymer rubber particles ("EXL2655" manufactured by Dow Chemical Japan Co., Ltd.) used in Example 1 was changed from 6 parts to 12 parts, the same operation as in Example 1 was performed to prepare the resin composition.

<Comparative Example 1> The same operation as in Example 1 was performed to prepare the resin composition, except that the amount of spherical silica ("SC2500SQ" manufactured by Admatex, which was surface treated) used in Example 1 was changed from 40 parts to 70 parts, and the amount of core-shell graft copolymer rubber particles ("EXL2655" manufactured by Dow Chemical Japan Co., Ltd.) used was changed from 6 parts to 5 parts.

<Comparative Example 2> Except that 6 parts of the core-shell graft copolymer rubber particles ("EXL2655" manufactured by Dow Chemical Japan Co., Ltd.) of Example 1 were not used, the same operation as Example 1 was carried out to prepare a resin composition.

<Comparative Example 3> The same operation as in Example 1 was performed to prepare a resin composition except that 42 parts of a phenoxy resin ("YX7553BH30" manufactured by Mitsubishi Chemical Corporation, solid content 30% by mass) was used instead of 40 parts of the phenolic hydroxyl-containing polybutadiene resin (non-volatile content 50% by mass) obtained in Synthesis Example 1.

<Test Example 1: Evaluation of Softness (MIT Folding Resistance)> The resin composition of each embodiment and comparative example was uniformly applied on the mold release treatment surface of a PET film (thickness 38 μm) treated with an alkyd mold release agent using a mold coater so that the thickness of the resin composition layer after drying would be 40 μm, and dried at 80-120°C (average 100°C) for 6 minutes to obtain a resin sheet.

The obtained resin sheet was laminated on a polyimide film (UPILEX S, manufactured by Ube Industries, Ltd.) using a batch vacuum pressure laminator ("MVLP-500" manufactured by Meiki Seisakusho Co., Ltd.). The lamination was performed by reducing the pressure for 30 seconds to a pressure of 13 hPa or less, and then pressing at 120°C for 30 seconds and a pressure of 0.74 MPa to obtain a resin sheet with a protective film. Thereafter, the PET film was peeled off from the resin sheet with a protective film, and the resin composition was cured under curing conditions of 190°C for 90 minutes, 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 bending resistance tester "MIT-DA" manufactured by Toyo Seiki Seisaku-sho) was used to measure the number of folding times until the hardened body broke under the test conditions of load 2.5N, bending angle 90 degrees, bending radius 1.0mm, and bending speed 175 times/minute according to JIS C-5016. In addition, the measurement was performed on 5 samples, and the average value of the first 3 points was calculated. The case where the number of folding times was less than 8,000 times was evaluated as "×", and the case where it was more than 8,000 times was evaluated as "○".

<Test Example 2: Evaluation of pattern embedding and flatness> <Test Example 2-1: Determination of minimum melt viscosity> The resin composition layer of the resin sheet obtained in Test Example 1 was measured for minimum melt viscosity using a dynamic viscoelasticity measuring device ("Rheosol-G3000" manufactured by UBM). 1 g of the sample resin composition sampled from the resin composition layer was heated from a starting temperature of 60°C to 200°C using a parallel plate with a diameter of 18 mm at a heating rate of 5°C/min. The dynamic viscoelasticity was measured under the measurement conditions of a temperature interval of 2.5°C, a vibration rate of 1 Hz, and a strain of 1 degree, and the minimum melt viscosity (poise) was measured.

<Test Example 2-2: Measurement of Adhesive Strength> The protective film was peeled off from the resin sheet with protective film obtained in Test Example ¹ , and the adhesive strength (N) of the resin composition layer was measured using a probe adhesion tester (TESTER SANGYO CO,. LTD., "TE-6002") with a glass probe of 5 mm in diameter under the conditions of load 1 kgf/cm2, contact speed 0.5 mm/sec, tensile speed 0.5 mm/sec, retention time 10 sec, and temperature 80°C. Adhesive strength exceeding 1.6 N was evaluated as "×", and less than 1.6 N was evaluated as "○".

<Test Example 2-3: Evaluation of Pattern Embedding and Holes> As an inner circuit substrate, a glass cloth-based epoxy resin double-sided copper laminate (copper foil thickness 18μm, substrate thickness 0.15mm, "HL832NSF LCA" manufactured by Mitsubishi Gas Chemical Co., Ltd., 255*340mm size) with a circuit conductor (copper) pattern formed on both sides with a 1mm square grid (residual copper rate of 59%) was prepared. The copper surface of both sides of the inner circuit substrate was roughened with "CZ8201" manufactured by MEC Co., Ltd. (copper etching amount 0.5μm).

The resin sheet obtained in Test Example 1 was laminated on both sides of the inner circuit board using a batch vacuum press (Nikko-Materials Co., Ltd., two-stage laminating press, CVP700) to make the resin composition layer contact the inner circuit board. Lamination was performed by reducing the pressure for 30 seconds, making the air pressure below 13 hPa, and pressing at 130°C and a pressure of 0.74 MPa for 45 seconds. Then, hot pressing was performed at 120°C and a pressure of 0.5 MPa for 75 seconds.

The inner circuit board with the resin sheet was placed in an oven at 100°C for 30 minutes, then moved to an oven at 180°C for 30 minutes to form an insulating layer. This was used as an "evaluation board".

The support was peeled off from the evaluation substrate, and the surface of the insulating layer was observed with a micro-optical microscope. Regarding pattern embedding, the case where the pattern was firmly embedded was evaluated as "○", and the case where the pattern was not embedded enough was evaluated as "×". Regarding holes, the case where no holes were generated was evaluated as "○", and the case where holes were generated was evaluated as "×".

The usage amounts of the non-volatile components of the resin compositions of the Examples and Comparative Examples, as well as the measurement results and evaluation results of the Test Examples are shown in Table 1 below.

It is known that by using a resin composition containing (A) a thermosetting resin, (B) an inorganic filler, 5% by mass or more of (C) an organic filler, and (D) an adhesive softener, it is possible to maintain excellent flexibility while suppressing adhesiveness. It is known that, in particular, when the (C) organic filler is less than 10% by mass, hole defects are suppressed and pattern embedding is excellent.

Claims (16)

A resin composition comprising (A) a thermosetting resin, (B) an inorganic filler, (C) an organic filler, (D) an adhesive softener, and (E) a curing agent, wherein the content of the component (B) is 20% by mass to 70% by mass based on 100% by mass of the nonvolatile components in the resin composition, the content of the component (C) is 5% by mass to 30% by mass based on 100% by mass of the nonvolatile components in the resin composition, and the content of the component (D) is 1% by mass to 50% by mass based on 100% by mass of the nonvolatile components in the resin composition. The resin composition as claimed in claim 1, wherein the content of the component (B) is 50 mass % or less when the non-volatile components in the resin composition are 100 mass %. The resin composition as claimed in claim 1, wherein the content of the component (C) is 10 mass % or less when the non-volatile components in the resin composition are 100 mass %. The resin composition according to claim 1, wherein the content of the component (C) is 6 mass % or more when the non-volatile components in the resin composition are 100 mass %. The resin composition as claimed in claim 1, wherein the component (D) is selected from the group consisting of a resin having a polybutadiene structure, a polyrotaxane resin, a polyimide resin, and a maleimide resin having a dimer acid skeleton. The resin composition as claimed in claim 1, wherein (C) the organic filler is a core-shell type graft copolymer particle. The resin composition as claimed in claim 6, wherein the monomer component forming the shell portion of the core-shell type graft copolymer particles is (meth)acrylate. The resin composition as claimed in claim 6, wherein the core particles of the core-shell type graft copolymer particles contain a thermoplastic elastomer. The resin composition as claimed in claim 1, wherein component (A) is an epoxy resin. The resin composition as claimed in claim 1, wherein the component (E) contains an active ester hardener. The resin composition as claimed in claim 1, wherein the solid content of the resin composition is 95 mass % or less. The resin composition as recited in claim 1 is used for forming an insulating layer of a multi-layer flexible substrate. A cured product of the resin composition according to any one of claims 1 to 12. A resin sheet comprises a support and a resin composition layer formed by the resin composition described in any one of claims 1 to 12 and disposed on the support. A multi-layer flexible substrate comprising an insulating layer formed by curing the resin composition described in any one of claims 1 to 12. A semiconductor device having the multi-layer flexible substrate according to claim 15.