Polymer compound, resin composition containing the polymer compound, film-shaped adhesive consisting of the resin composition, cured product of the resin composition, and cured product of the film-shaped adhesive

Abstract

The present invention provides a polymer compound represented by formula (1) below, which has excellent solubility in low-boiling-point solvents such as toluene. By using the polymer compound represented by formula (1), a hardened material can be provided, which has sufficient flexibility for thin film formation, high adhesion to low-roughness copper foil, low dielectric constant and dielectric loss tangent, and low linear expansion rate; In formula (1), R1, R2, R3, and R4 independently represent methyl, ethyl, isopropyl, or tert-butyl, respectively. X independently represents acetyl or a partial structure shown in formula (2) below, except that more than 5% of the plurality of X are structures shown in formula (2). Y represents residues after removing two amino groups from a diamine compound. n is the average number of repeating units and ranges from 1 to 100; (In formula (2), R5 represents a hydrogen atom or a methyl group).

Description

Polymer compounds and resin compositions containing such polymer compounds This invention relates to a polymer compound that can be easily formed into a film by casting a solution into a substrate. It can be thermally or photocured by using a free radical initiator, and the cured product has excellent dielectric properties, adhesion, and heat resistance. Phenoxy resin is a high molecular weight compound obtained by polymerizing a difunctional epoxy resin with a difunctional phenolic compound. By adding this phenoxy resin, ordinary epoxy resin compositions or free radical polymerizable compositions can be formed into thin films. Therefore, it is used as an important component of thin film adhesives in a wide range of fields, especially in the power / electronics industry as an interlayer insulating layer for printed circuit boards and as resin-coated copper foil. While cured resin compositions containing phenoxy resin exhibit excellent adhesion and film-forming ability, they suffer from low heat resistance and high dielectric constant and dielectric loss tangent (approximately 3.5 dielectric constant and 0.03 dielectric loss tangent at 1 GHz). Therefore, they are practically unsuitable for applications in electronic devices with increasingly high signal response speeds. Resins with excellent dielectric properties are generally known to be high-molecular-weight fluorine compounds such as polytetrafluoroethylene (PTFE) (Patent Document 1) or liquid crystal polymers (Patent Document 2). However, these resins have extremely low compatibility with other resins and insufficient adhesion. While aromatic bismaleimides are known to possess excellent heat resistance and dielectric properties, they generally exhibit poor solvent solubility, dissolving only in high-boiling-point aprotic polar solvents such as NMP or DMF. Therefore, they are unsuitable for use in electronic materials applications utilizing low-boiling-point solvents such as toluene or methyl ethyl ketone. Furthermore, their cured forms are typically rigid and lack flexibility, making them unsuitable for thin-film applications. Although Patent Document 3 discloses a method for increasing the molecular weight of aromatic bismaleimides through a Michael addition reaction with an aliphatic diamine to improve solvent solubility, the polymer formed from this bismaleimide and diamine compound exhibits poor stability and a tendency to gel due to the reactivity of the residual secondary amine in its structure with the terminal maleimide group. Patent documents 4 and 5 disclose a method for improving stability by reacting the secondary amine in the addition reaction product of bismaleimide and diamine with acetic anhydride to acetylate it. However, the resin obtained by such a method has an extremely high linear expansion rate in the cured form, which is not suitable for applications such as electronic devices that require high reliability. [Previous Technical Documents] [Patent Literature] [Patent Document 1] Japanese Patent Application Publication No. 2005-001274 [Patent Document 2] Japanese Patent Application Publication No. 2014-060449 [Patent Document 3] Japanese Patent Application Publication No. 2006-241300 [Patent Document 4] Japanese Patent No. 6948907 [Patent Document 5] US Publication No. 8,637,611 The present invention was developed in view of the above-mentioned problems, and its purpose is to provide a polymer compound with excellent solubility in low-boiling-point solvents such as toluene, and a hardened form of the polymer compound. The hardened form of the polymer compound has sufficient flexibility to be made into a thin film, high adhesion to low-roughness copper foil, low dielectric constant and dielectric loss tangent, and low linear expansion rate. The inventors conducted in-depth research and discovered that the above-mentioned problems could be solved by using a resin composition system containing a polymer compound with a specific structure, thus completing the present invention. That is, this invention relates to the following: (1) A polymer compound as shown in the following formula (1); In equation (1), R 1. R 2. R 3 and R 4 represents methyl, ethyl, isopropyl, or tributyl, respectively. X represents acetyl or a partial structure as shown in formula (2) below, wherein at least one of the plurality of X is acetyl, and more than 5% of the plurality of X are structures as shown in formula (2). Y represents residues after removing two amino groups from a diamine compound; n is the average number of repeating units and ranges from 1 to 100; (In equation (2), R) 5 represents a hydrogen atom or a methyl group. (2) A resin composition comprising the polymeric compound and free radical initiator described in paragraph (1) above. (3) The resin composition described in (2) above further contains a free radical reactive monomer, which has a free radical reactive functional group. (4) The resin composition described in paragraph (2) above further contains a free radical reactive polymer, which has two or more free radical reactive functional groups in one molecule. (5) A film adhesive comprising the resin composition described in any one of the preceding items (2) to (4). (6) A hardened material is a hardened material of the resin composition described in any one of (2) to (4) above. (7) A hardened material, which is a hardened form of the thin-film adhesive described in paragraph (5) above. The present invention provides a polymer compound and a resin composition containing the polymer compound. The polymer compound and the resin composition containing the polymer compound can be cured by using a free radical initiator and applying heat or light energy. The cured resin composition has excellent dielectric properties, adhesion and heat resistance. The following describes various embodiments of the present invention. The polymer compound represented by formula (1) of this invention is a reactant obtained by the following method: (1) A copolymer (C) of a diamine compound (A) (hereinafter referred to as "compound (A)") and a bismaleimine compound (B) (hereinafter referred to as "compound (B)") with a specific structure in excess of compound (A) in molar number was synthesized. (2) Reacting 5% to 100% of the secondary amine groups in copolymer (C) with the isocyanate groups in compound (D) (hereinafter referred to as "compound (D)") which has isocyanate groups and (meth)acrylic acid groups. (3) React the residual secondary amine groups in the reactants of copolymer (C) and compound (D) with acetic anhydride. First, the copolymer (C) of the intermediate raw material of the polymer compound of the present invention will be described. The copolymer (C) is a copolymer (McC addition reaction product) of compound (A) and compound (B) in excess of compound (A) in terms of molar number. The compound (A) used as a raw material for copolymer (C) is not particularly limited as long as it contains two amino groups per molecule. Specific examples include: 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, hexamethylenediamine, 1,8-diaminooctane, 1,10-diaminodecane, 1,12-diaminododecane, 4,4'-methylenebicyclohexanediamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, isophoronediamine, norbornenediamine, and dimer diamine. diamine), 3,3'-diamino-N-methyldipropylamine, diaminomaleonitrile, 1,3-diaminopentane, 9,10-diaminophenanthrene, 4,4'-diaminooctafluorobiphenyl, 3,5-diaminobenzoic acid, 3,7-diamino-2-methoxyfenozyl, 4,4'-diaminodiphenyl ketone, 3,4-diaminodiphenyl ketone, 3,4-diaminotoluene, 2,6-diaminoanthraquinone, 2,6-diaminotoluene, 2,3-diaminotoluene, 1,8-diaminonaphthalene, 2,4-Diaminotoluene, 2,5-Diaminotoluene, 1,4-Diaminoanthraquinone, 1,5-Diaminoanthraquinone, 1,5-Diaminonaphthalene, 1,2-Diaminoanthraquinone, 2,4-isopropylphenylenediamine, 1,3-diaminomethylbenzene, 1,3-diaminomethylcyclohexane, 2-chloro-1,4-diaminobenzene, 1,4-diamino-2,5-dichlorobenzene, 1,4-diamino-2,5-dimethylbenzene, 4,4'- -diamino-2,2'-bis(trifluoromethyl)biphenyl, bis(amino-3-chlorophenyl)ethane, bis(4-amino-3,5-dimethylphenyl)methane, bis(4-amino-3,5-diethylphenyl)methane, 2,3-diaminonaphthalene, bis(4-amino-3-methylphenyl)methane, bis(4-amino-3-ethylphenyl)methane, 4,4'-diaminophenyl arsenide, 3,3'-diaminophenyl arsenide, 2,2- bis(4,(4-aminophenoxy)phenyl) guanidine, 2,2-bis(4-(3-aminophenoxy)phenyl) guanidine, 4,4'-diaminodiphenyl ether (4,4'-oxydianiline), 4,4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl ether, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)phenyl 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diamino-3,3'-dimethoxybiphenyl, 9,9-bis(4-aminophenyl)biphenyl, 1,3-bis(4-aminophenoxy)-2,2-dimethylpropane, 1,3-bis(4-aminophenoxy)propane, 1,4-bis(4-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)butane, 2,3,5,6-Tetramethyl-1,4-phenylenediamine; 3,3',5,5'-tetramethylbenzidine; 2,2-bis(4-aminophenyl)hexafluoropropane; m-xylylendiamin; p-phenylenediamine; bis(4-amino-3-methylcyclohexyl)methane; 1,2-bis(2-aminoethoxy)ethane, etc. Furthermore, the residues (divalent linkages) after removing the two amino groups of compound (A) are equivalent to Y in formula (1). Compound (A) is preferably an aliphatic diamine compound with 2 or more carbon atoms, and specific examples include: 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, hexamethylenediamine, 1,8-diaminooctane, 1,10-diaminodecane, 1,12-diaminododecane, 4,4'-methylenebicyclohexanediamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, isophoronediamine, norbornenediamine, and dimer diamine, etc. In formula (1), Y is preferably a residue (divalent linker) obtained by removing two amino groups from the above-mentioned aliphatic diamine compound with two or more carbon atoms. Compound (B) uses a bismaleimine compound obtained by a condensation ring-closing reaction of a bis-3,5-dialkyl-4-aminophenylmethane compound with maleic acid, wherein the four alkyl groups in the compound are independently methyl, ethyl, isopropyl or tert-butyl. Specific examples of compound (B) include: 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 3,3',5,5'-tetramethyl-4,4'-diphenylmethane bismaleimide, 3,3',5,5'-tetraisopropyl-4,4'-diphenylmethane bismaleimide, etc. The alkyl group of the above compound (B) corresponds to R in formula (1) described below. 1 to R 4. The alkyl group of compound (B) is preferably methyl or ethyl. In compound (B), since the "bismaleimine compound with hydrogen atoms at the adjacent positions of the carbon atoms on the benzene ring bonded to the maleimine group" has high reactivity with the secondary amine group, it is prone to gelation during the copolymerization reaction of the copolymer (C) due to the reaction of the adjacent hydrogen atoms with the amine group of compound (A). However, by using compound (B) with alkyl groups at both the adjacent and adjacent positions, gelation during the copolymerization reaction with compound (A) can be prevented. When synthesizing copolymer (C), the amount of compound (A) and compound (B) used is generally less than that of compound (B) in moles. For example, 0.4 to 0.98 moles of compound (A) are more preferably 0.5 to 0.96 moles of compound (B) compared to 1 mole of compound (B). The reaction temperature during synthesis is typically 50 to 150°C, preferably 60 to 140°C, and the reaction time is typically 0.5 to 30 hours, preferably 1 to 20 hours. A reaction catalyst may also be used. The reaction endpoint is defined as the point at which the molecular weight, obtained by GPC (gel permeation chromatography), fails to increase from a certain value. The solvent used in the reaction can be distilled off under heating and reduced pressure, or it can be used directly in the resin composition containing the solvent. In the copolymerization reaction of compound (A) and compound (B), a solvent is preferably used. Examples of suitable solvents include toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and propylene glycol monomethyl ether acetate. The amount of solvent used is preferably 10 to 300% by mass, more preferably 20 to 200% by mass, relative to the solid content of the raw materials used in the copolymerization reaction. The number average molecular weight of the copolymer (C) is typically between 1,000 and 100,000, preferably between 1,500 and 80,000. To obtain a copolymer (C) with a number average molecular weight within the aforementioned range, the raw material components are simply added at the aforementioned ratios. By measuring this number average molecular weight, the value of n in formula (1) can be calculated. n is the average number of repeating units, which is in the range of 1 to 100. If it is within this range, the effects of the polymer compound of the present invention can be achieved. Furthermore, the molecular weight in this specification refers to the value calculated from the polystyrene content based on the results of GPC measurements. Secondly, the polymer compound of the present invention will be described. The polymer compound of the present invention is obtained by reacting 5% or more but less than 100% of the secondary amine groups present in the aforementioned copolymer (C) with the isocyanate groups in the compound (D) shown in the following formula (3), thereby reacting the remaining secondary amine groups in the aforementioned reactant with acetic anhydride to achieve acetylation. Furthermore, R in equation (3) 5 represents R in equation (2) 5 has the same meaning. That is, R in equation (2) The 5 series originates from the hydrogen atom or methyl group present in compound (D). Specific examples of compound (D) include: ethyl 2-isocyanate methacrylate (manufactured by Karenz MOI Showa Denko Co., Ltd.), ethyl 2-isocyanate acrylate (manufactured by Karenz AOI Showa Denko Co., Ltd.), etc. Regarding the amounts of copolymer (C) and compound (D) used in the synthesis of the polymeric compound of the present invention, the amount of compound (D) is preferably 0.05 to 0.9 mol, more preferably 0.1 to 0.8 mol, relative to 1 mol equivalent of secondary amino groups in copolymer (C). The reaction temperature is preferably 10 to 90°C, and the reaction time is preferably 30 minutes to 5 hours. By adding acetic anhydride to the reactant of the obtained copolymer (C) and compound (D), the residual secondary amine groups can be acetylated. A preferred method for synthesizing the polymer compound of the present invention is as follows: copolymerization of compound (A) and compound (B) is carried out in a solvent; compound (D) is added to the resulting copolymer (C) solution to carry out the reaction; and acetic anhydride is further added to the resulting reaction solution to carry out acetylation. The amount of acetic anhydride used in the synthesis of the polymer compound of the present invention is only the same as or greater than the molar number of the residual secondary amine in the reactants of copolymer (C) and compound (D). The reaction temperature is preferably 10 to 90°C, and the reaction time is preferably 30 minutes to 5 hours. After the reaction is completed, the generated acetic acid and excess acetic anhydride can be removed by washing with water. The resin composition of this invention contains the polymeric compound and free radical initiator of this invention. Preferred thermal free radical initiators include, for example, benzoyl peroxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)-3-hexyne, di-tert-butylperoxide, cumene tributylperoxide, α,α-bis(tert-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, dicumene peroxide, di(tert-butylperoxy)isophthalate, tert-butyl peroxybenzoate, 2,2-bis(tert-butylperoxy)butane, 2,2-bis(tert-butylperoxy)octane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, di(trimethylsilyl)peroxide, and trimethylsilyltriphenylsilylperoxide, among other peroxides. Examples of good photoradical initiators include: benzoin, benzoin methyl ether, benzoin ethyl ether, and other benzoin and its alkyl ethers; acetophenones, such as 2,2-dimethoxy-2-phenylacetophenone and 1,1-dichloroacetophenone; anthraquinones, such as 2-methylanthraquinone, 2-pentylanthraquinone, 2-tert-butylanthraquinone, and 1-chloroanthraquinone; thioxanthraquinones, such as 2,4-dimethylthioxanthraquinone, 2,4-diisopropylthioxanthraquinone, and 2-chlorothioxanthraquinone; ketals, such as acetophenone dimethyl ketal and benzyl dimethyl ketal; diphenyl ketones; 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-propane-1-one or 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butanone-1; acylphosphine oxide. Oxides and xanthones, etc. The content of the free radical initiator in the resin composition of the present invention is typically 0.1 to 10 parts by mass relative to the total of 100 parts by mass of the polymer compound and the free radical reactive monomers, which are described later as optional components. It is more preferably 0.1 to 8 parts by mass. The resin composition of the present invention may contain more free radical reactive monomers. By containing more free radical reactive monomers, the reactivity of the resin composition and the heat resistance of the cured product can be improved. Furthermore, the free radical reactive monomer system in the present invention refers to a compound having one or more free radical reactive functional groups in one molecule, and having a number average molecular weight of 500 or less (the lower limit of the number average molecular weight is approximately 100). Specific examples of free radical reactive monomers include: acenaphthylene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, neopentyl glycol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, glycerol dimethacrylate, 2-hydroxy-3-acryloxypropyl methacrylate, bisphenol A alkylene oxide adduct methacrylate, trimethylolpropane trimethacrylate, tricyclodecanediethanol dimethacrylate, and glycerol dimethacrylate. Dimethacrylate, trimethylolpropane trimethacrylate, ethoxylated triisocyanate, ε-caprolactone-modified tris(2-acryloxyethyl)triisocyanate, neopentyl terephthalate triacrylate, di(trimethylolpropane)tetraacrylate, ethoxylated neopentyl terephthalate tetraacrylate, neopentyl terephthalate tetraacrylate, dinepentyl terephthalate polyacrylate, dinepentyl terephthalate hexaacrylate, triallyl triisocyanate, triallyl triisocyanate, divinylbenzene, divinyl isophthalate, N-phenyl-maleimide, N-phenyl-methylmaleimide, N-phenyl-chloromaleimide Amine, N-p-chlorophenyl-maleimide, N-p-methoxyphenyl-maleimide, N-p-methylphenyl-maleimide, N-p-nitrophenyl-maleimide, N-p-phenoxyphenyl-maleimide, N-p-phenylaminophenyl-maleimide, N-p-phenoxycarbonylphenyl-maleimide, 1-maleimide-4-acetoxysuccinimide-benzene, 4-maleimide-4'-acetoxysuccinimide-diphenylmethane, 4-maleimide- Examples of suitable maleic anhydride-diphenyl ethers include 4'-acetoxysuccinimide-diphenyl ether, 4-maleimide-4'-acetylamine-diphenyl ether, 2-maleimide-6-acetylamine-pyridine, 4-maleimide-4'-acetylamine-diphenylmethane, N-p-phenylcarbonylphenyl-maleimide, N-ethylmaleimide, N-2,6-dimethylmaleimide, N-cyclohexylmaleimide, N-2,3-dimethylmaleimide, dimethylmaleimide, 2,6-dimethylmaleimide, and 4,4'-bismaleimide-diphenylmethane, but those with a maleimide group as a functional group are preferred. These free radical reactive monomers can be used alone or in combination of two or more. The resin composition of the present invention may further contain free radical reactive polymers. By further containing free radical reactive polymers, the adhesion of the resin composition of the present invention and the heat resistance of the cured product can be improved. Furthermore, the free radical reactive polymer in the present invention refers to a compound having one or more free radical reactive functional groups (preferably two or more) in one molecule, and having a number average molecular weight of 500 or more. Specific examples of free radical reactive polymers include: copolymers of styrene and butadiene, modified polyphenylene ether resins, bismaleimides extended by amides, or polymers represented by formula (4) below. Furthermore, m in formula (4) is the average number of repeating units and is a real number in the range of 1 to 20. Copolymers of styrene and butadiene, which are free radical reactive polymers, can be random copolymers (commonly known as SBRs) or block copolymers. They can also be those in which hydrogenation causes the double bonds originating from butadiene in the block copolymer to form saturated hydrocarbons (commonly known as SEBS resins). The ratio of styrene to butadiene in the polymer is typically 10:90 to 90:10, and its number average molecular weight is typically 1,000 to 100,000. Specific examples of SBR products include Ricon100, Ricon181, and Ricon184 from CRAY VALLEY. Specific examples of SEBS resin products include the Tuftec series from Asahi Kasei Corporation and the G polymer series from Kraton Corporation. Modified polyphenylene ether resins belonging to free radical reactive polymers are preferably compounds having methacryl, acrylonitrile, or vinyl groups at both ends of the molecule, and having a number average molecular weight of 1,000 to 10,000. Specific examples include compounds with methacryl groups at both ends and a number average molecular weight of about 1,700, represented by formula (5) below (product name SA9000, manufactured by SABIC Japan Contract Company), or compounds with vinyl groups at both ends and a number average molecular weight of about 1,200 or 2,200, represented by formula (6) below (product name OPE-2St 1200 or OPE-2St 2200, manufactured by Mitsubishi Gas Chemical Co., Ltd.). The bismaleimide resin system, which belongs to the category of free radical reactive polymers and is extended by acetimine, can be obtained by a known method described in Japanese Patent Publication No. 5,328,006, etc. Specifically, it is obtained by performing a dehydration condensation reaction in an organic solvent on an aliphatic diamine and an aromatic or aliphatic tetracarboxylic dianhydride with the aliphatic diamine in excess in a molar ratio using an acid catalyst, thereby causing the amino groups present at the polymer terminal to undergo dehydration condensation with the maleic anhydride, and then removing the catalyst by washing with water. Specific examples of aliphatic diamines include: 1,10-diaminodecane; 1,12-diaminododecane; dimerized diamine; 1,2-diamino-2-methylpropane; 1,2-diaminocyclohexane; 1,2-diaminopropane; 1,3-diaminopropane; 1,4-diaminobutane; 1,5-diaminopentane; 1,7-diaminoheptane; 1,8-diaminomenthtane; 1,8-diaminooctane; 1,9-diaminononane; 3,3'-diamino-N-methyldipropylamine; diaminomaleonitrile; 1,3-diaminopentane; 9,10-diaminophenanthrene, etc., but dimerized diamines are particularly preferred. Specific examples of aromatic or aliphatic tetracarboxylic dianhydrides include: pyromellitic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, bicyclo(2.2.2)oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, diethylenetriaminepentaacetic dianhydride, ethylenediaminetetraacetic dianhydride, 3,3',4,4'-diphenylketonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 4,4'-oxydiphthalic anhydride. anhydride), 3,3',4,4'-diphenyl tannic acid dianhydride, 2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 4,4'-bisphenol A phthalic anhydride, 5-(2,5-dioxytetrahydro)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, ethylene glycol bis(triphenylamine), hydroquinone phthalic anhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride (CBDA), 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2... 4,5-Cyclohexanetetracarboxylic dianhydride, 1,1'-bicyclohexane-3,3',4,4'-tetracarboxylic acid-3,4:3',4'-dianhydride, 4-(2,5-di-side-oxytetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic dianhydride, 5-(2,5-di-side-oxytetrahydrofuran)-3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 3,5,6-tricarboxy-2-norborneneacetic acid dianhydride, etc., with pyromellitic tetracarboxylic anhydride and 1,2,4,5-cyclohexanetetracarboxylic dianhydride being particularly preferred. Specific product names can be listed as BMI-3000 from Designer Molecules Inc. The resin composition of the present invention may further contain organic solvents. Specific examples of organic solvents include: aromatic solvents such as toluene and xylene; ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether monoacetate, and propylene glycol monobutyl ether; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone; lactones such as γ-butyrolactone and γ-valerolactone; amide solvents such as N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide, and N,N-dimethylimidazolidinedione; amides such as tetramethylene sulfide; etc. The content of organic solvents in the resin composition of the present invention is generally 90% by mass or less, preferably 30% to 80% by mass. The resin composition of this invention may contain polymerization inhibitors to improve storage stability. The polymerization inhibitors that can be used are not particularly limited if they are generally known, such as: benzoquinones such as hydroquinone, methylhydroquinone, p-benzoquinone, tetrachlorobenzoquinone, and trimethylbenzoquinone; or aromatic diols, di-tert-butylhydroxytoluene, etc. The resin composition of this invention can be formulated with fillers or additives in appropriate amounts, within a range that does not impair the original properties, to impart the desired properties according to its intended use. Fillers can be fibrous or powdered, and examples include: silica, carbon black, alumina, talc, mica, glass beads, hollow glass spheres, etc. The resin composition of this invention may further contain flame-retardant compounds, additives, etc. These are not particularly limited for general users. Examples of flame-retardant compounds include: brominated compounds such as 4,4-dibromobiphenyl; nitrogen compounds such as phosphate esters, melamine phosphate, phosphorus-containing epoxy resins, melamine, and benzoguanamine; compounds containing oxazine rings; and silicone compounds. As additives, ultraviolet absorbers, antioxidants, photopolymerization initiators, fluorescent whitening agents, photosensitizers, dyes, pigments, tackifiers, lubricants, defoamers, dispersants, leveling agents, and gloss agents may be appropriately combined as desired. The resin composition of this invention can be coated or impregnated onto various substrates. For example, when using a thermal free radical initiator, it can be used as an interlayer insulating layer in a multilayer printed circuit board by coating it onto a PET film, as a cover layer by coating it onto a polyimide film, or as a resin-coated copper foil by coating it onto copper foil and drying it. Furthermore, by impregnating it with glass cloth or cellophane, carbon fiber, various nonwoven fabrics, etc., it can be used as a prepreg for printed circuit boards or CFRP. Moreover, it can also be used as various resists by using a photofree radical initiator. The interlayer insulating layer or covering layer, resin-coated copper foil, prepreg, etc. of the present invention can be hardened by heating and pressing with a hot press or the like. (Example) The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited to these examples. Example 1 (Synthesis of the polymer compound of the present invention) A flask equipped with a thermometer, cooling pipe, nitrogen inlet pipe, and stirrer was filled with 22.10 parts (0.05 moles) of 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide (product name: BMI-70, manufactured by K.I. Chemical Industry Co., Ltd.), 20.18 parts (0.0375 moles) of dimer diamine (product name: Priamine 074, manufactured by Croda), and 20 parts of toluene. The mixture was reacted at 100°C for 8 hours under nitrogen to obtain a toluene solution of copolymer 1 (corresponding to copolymer (C) of the intermediate raw material of the polymer compound of the present invention, where Y in formula (7) represents the residue after removing two amino groups from the dimer diamine) as shown in formula (7). The number average molecular weight of copolymer 1 is 2,700, and the weight average molecular weight is 15,100. The value of n in formula (7) is calculated to be 2.5 from the number average molecular weight. 1.16 parts (0.0075 moles) of Karenz MOI (manufactured by Showa Denko Co., Ltd.) were added to a toluene solution of the copolymer, and the mixture was reacted at 60°C for 1 hour. Then, 6.12 parts (0.0675 moles) of acetic anhydride were added, and the mixture was further reacted at 60°C for 1 hour. After dilution with 100 parts of toluene, 50 parts of pure water were added, and the by-product acetic acid was removed by stirring and washing. The washing was repeated until the aqueous layer became neutral, and the toluene solution was concentrated to obtain a 25% by mass toluene solution of the polymer compound of the present invention. It is presumed that in the obtained polymer compound, 10% of X in formula (1) is derived from Karenz MOI, and the remainder is acetyl. Comparative Example 1 (for comparison in the synthesis of polymer compounds) Except for omitting the step of adding Karenz MOI and reacting at 60°C for 1 hour, and changing the amount of acetic anhydride added to 7.65 parts (0.075 moles), the method of Example 1 was followed to obtain a 25% by mass toluene solution of the comparative polymer. It is presumed that in the obtained polymer, all X in formula (1) is acetylated. Example 2, Comparative Example 2 (Preparation of Resin Composition) 0.05 parts of dicumyl peroxide, as a free radical initiator, were added to 10 parts of the polymer compound solution obtained in Example 1 and Comparative Example 1, and mixed uniformly to obtain the resin composition of the present invention and the resin composition for comparison, respectively. (Evaluation of the dielectric properties, glass transition temperature and linear expansion coefficient (α1) of the cured resin composition) Using an applicator, the resin compositions obtained in Example 2 and Comparative Example 2 were coated to a mirror surface of a copper foil with a thickness of 18 μm to a thickness of 280 μm. The solvent was dried by heating at 90°C for 10 minutes to obtain a thin-film adhesive. The thin-film adhesive on the copper foil was then cured at 180°C for 1 hour using a vacuum oven, followed by immersion in an etching solution to remove the copper foil. Since both the thin-film adhesive of this invention and the comparative thin-film adhesive yielded a cured product with a thickness of 70 μm suitable for use as a film, the dielectric properties of the resulting cured products were evaluated. The dielectric properties were determined using a network analyzer 8719ET (manufactured by Agilent Technologies) with cavity resonance method at 10 GHz for the dielectric constant and dielectric loss tangent. Furthermore, the glass transition temperature and linear expansion coefficient (α1) of the cured product of the thin-film adhesive were determined using a TMA (thermomechanical measurement apparatus). The results are shown in Table 1. (Evaluation of the adhesion strength and heat resistance of the cured resin composition) Using a coating applicator, the resin compositions obtained in Example 2 and Comparative Example 2 were coated to a thickness of 50 μm onto the matte surface of a 12 μm thick low-roughness copper foil (CF-T4X-SV: manufactured by Fukuda Metal Foil Powder Co., Ltd.). The solvent was dried by heating at 90°C for 10 minutes, thereby obtaining a copper foil with a thin-film adhesive composed of the resin composition of the present invention. The matte surfaces of other copper foils (of the same type) were overlapped onto the adhesive surface of the aforementioned copper foil, and the foil was heated and hardened under vacuum at a pressure of 3 MPa for 1 hour. The 90° peel strength (adhesion strength) between the copper foils was then measured using a universal testing machine AGX-50 (manufactured by Shimadzu Corporation). Furthermore, the laminated copper foil was cut into 3 cm squares and floated in a solder bath at 288°C. The time until abnormalities such as expansion and peeling occurred on the copper foil was measured. The results are shown in Table 1. [Table 1] Evaluation results of cured resin compositions Example 3 (Preparation of the resin composition of the present invention) In 10 parts of the polymer compound solution of the present invention obtained in Example 1, 0.05 parts of dicumyl peroxide as a free radical initiator and 0.5 parts of Ricon 100 (manufactured by CRAY VALLEY), a copolymer of butadiene and styrene, were added and mixed uniformly to obtain the resin composition of the present invention. Example 4 (Preparation of the resin composition of the present invention) In Example 1, 0.05 parts of dicumyl peroxide as a free radical initiator and 0.5 parts of modified polyphenylene ether resin SA-9000 (manufactured by SABIC Contracts) were added to 10 parts of the polymer compound solution of the present invention and mixed uniformly to obtain the resin composition of the present invention. Example 5 (Preparation of the resin composition of the present invention) In Example 1, 0.05 parts of dicumyl peroxide as a free radical initiator and 0.5 parts of bismaleimide resin BMI-3000 (manufactured by Designer Molecules Inc.) extended by nimidylamine were added to 10 parts of the polymer compound solution of the present invention and mixed uniformly to obtain the resin composition of the present invention. (Evaluation of cured resin composition) The properties of the resin compositions obtained in Examples 3 to 5 were evaluated using the same methods as those used in the evaluation of "Dielectric properties, glass transition temperature and linear expansion coefficient (α1) of the cured resin composition" and "Adhesion strength and heat resistance of the cured resin composition". The results are shown in Table 2. [Table 2] Evaluation results of cured resin compositions As described above, the polymeric compounds of the present invention can be hardened by using a free radical initiator to form a flexible film, and the hardened film exhibits excellent dielectric properties, adhesion and heat resistance.

Claims

1. A polymer compound as shown in the following formula (1), wherein R1, R2, R3 and R4 independently represent methyl, ethyl, isopropyl or tert-butyl, respectively; X independently represent acetyl or a partial structure shown in the following formula (2), wherein at least one of the plurality of X is acetyl, and more than 5% of the plurality of X are structures shown in formula (2); Y represents residues after removing two amino groups from a dimer diamine; n is the average number of repeating units in the range of 1 to 100 in formula (2), and R5 represents a hydrogen atom or a methyl group.

2. A resin composition comprising the polymeric compound described in claim 1 and a free radical initiator.

3. The resin composition as described in claim 2 further contains a radical reactive monomer having a radical reactive functional group.

4. The resin composition as described in claim 2 further contains a free radical reactive polymer having two or more free radical reactive functional groups in one molecule.

5. A film-like adhesive comprising the resin composition described in any one of claims 2 to 4.

6. A cured compound, which is a cured compound of the resin composition described in any one of claims 2 to 4.

7. A cured product, which is a cured product of the film adhesive described in claim 5.