Hardening polymeric compounds and resin compositions containing such compounds

Abstract

To provide a curable polymer compound that can be formed in a film shape.SOLUTION: A polymer compound results from the reaction of a random copolymer, represented by formula (2) as an intermediate material, with either (meth)acrylic acid chloride or (meth)acrylic acid (where R1 represents a hydrogen atom or a methyl group. R3, R4 and R5 independently represent a hydrogen atom or an alkyl group. l, m and n are the average number of repeating units, each independently ranging from 1 to 2,000).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a novel polymer compound that can be easily formed into a film by casting an organic solvent solution containing the polymer compound onto a substrate. A resin composition combined with a radical initiator can be thermally or photocured, and the cured product has excellent dielectric properties, adhesiveness, and heat resistance.

Background Art

[0002] Phenoxy resin is a polymer compound with a very large molecular weight obtained by polymerizing a bifunctional epoxy resin and a bifunctional phenol compound. By adding this phenoxy resin, general epoxy resin compositions and radical polymerizable compositions can be formed into films, so it is used in a wide range of fields as an important component of film adhesives, and particularly in the electrical and electronic fields, it is used for interlayer insulating layers of printed wiring boards and copper foils with resin.

[0003] While cured resin compositions containing phenoxy resin exhibit excellent adhesion and film-forming ability, they have low heat resistance and high dielectric constant and dielectric loss tangent (generally around 3.5 and 0.03 at a frequency of 1 GHz). As a result, they are unsuitable for use in modern electronic equipment applications with high signal response speeds. Although polymeric fluorine compounds such as polytetrafluoroethane (PTFE) (Patent Document 1) and liquid crystal polymers (Patent Document 2) are generally known as resins with excellent dielectric properties, these resins have extremely low compatibility with other resins and insufficient adhesion. Patent Document 3 describes a curable polymer compound obtained by esterifying a monomer having one or more ethylenically unsaturated groups and one carboxyl group to an aliphatic hydroxyl group in a random copolymer of a monomer having one or more ethylenically unsaturated groups at a concentration of 70% by weight or less and a (meth)acrylate having one or more aliphatic hydroxyl groups at a concentration of 30% by weight or more. However, when the present inventors conducted further tests, the cured product of the curable polymer compound obtained from the structural formula in the same document had a dielectric loss tangent of about 0.005 at 10 GHz, which does not sufficiently satisfy the low dielectric properties required for current high-frequency circuit board applications. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2005-001274 [Patent Document 2] Japanese Patent Publication No. 2014-060449 [Patent Document 3] Japanese Patent Application Publication No. 10-017812 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The present invention has been made in view of the above points, and aims to provide a curable polymer compound that has sufficient flexibility to be formed into a film, and in which the cured product of the composition used in combination with a radical initiator has high heat resistance, high adhesion to low-roughness copper foil, and low dielectric constant and dielectric loss tangent. [Means for solving the problem]

[0006] As a result of diligent research, the inventors of the present invention have found that a polymer compound obtained by dehydrochlorinating a compound in which one of the hydroxyl groups of a dihydroxybenzene compound is (meth)acrylated, a copolymer of styrene and N-phenylmaleimide compounds, and a chloride group of (meth)acrylic acid chloride solves the above problems, and have completed the present invention. In other words, the present invention is (1) The following formula (1)

[0007] [ka]

[0008] A polymer compound represented by the formula (wherein R1 and R2 each independently represent a hydrogen atom or a methyl group. R3, R4, and R5 each independently represent a hydrogen atom or an alkyl group. l, m, and n are the average values ​​of the number of repeating units, each independently ranging from 1 to 2,000.) (2) A resin composition comprising the polymer compound and radical initiator described in item (1) above, (3) The resin composition according to item (2) above, further comprising a compound having a radical reactive group, (4) A film-like adhesive comprising the resin composition described in item (2) or (3) above, and (5) Cured product of the resin composition described in item (2) or (3) above, Regarding. [Effects of the Invention]

[0009] The polymer compound of the present invention has sufficient flexibility to be formed into a film, and by curing a resin composition containing the polymer compound in combination with a radical initiator using heat or light energy, a cured product with excellent dielectric properties, adhesion, and heat resistance can be obtained. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below. The polymer compound represented by formula (1) of the present invention is obtained by reacting a random copolymer represented by the following formula (2) with (meth)acrylic acid chloride or (meth)acrylic acid as an intermediate raw material. In formula (2), R1, R3, R4, R5, l, m, and n have the same meanings as R1, R3, R4, R5, l, m, and n in formula (1).

[0011] [ka]

[0012] First, let's explain the intermediate raw material represented by the above formula (2) (a random copolymer of (meth)acrylate having a phenolic hydroxyl group, styrene, and an N-phenylmaleimide compound, hereinafter simply referred to as "polymer"). The (meth)acrylate having a phenolic hydroxyl group, which is the raw material for the copolymer, is not particularly limited as long as it is a compound having a phenolic hydroxyl group and a (meth)acryloyl group in one molecule. Examples include 4-hydroxyphenyl methacrylate, 2-hydroxyphenyl methacrylate, 3-hydroxyphenyl methacrylate, 4-hydroxyphenyl acrylate, 2-hydroxyphenyl acrylate, and 3-hydroxyphenyl acrylate, but 4-hydroxyphenyl methacrylate is preferred. In this specification, the term "(meth)acrylate" refers to both "acrylate and methacrylate."

[0013] Examples of N-phenylmaleimide compounds used as raw materials for copolymers include N-phenylmaleimide, N-(4-methylphenyl)maleimide, N-(3-methylphenyl)maleimide, N-(2-methylphenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, N-(2,4-dimethylphenyl)maleimide, and N-(4-t-butylphenyl)maleimide, but N-phenylmaleimide is particularly versatile and preferred.

[0014] The copolymerization method for (meth)acrylates having phenolic hydroxyl groups, styrene, and N-phenylmaleimide compounds is not particularly limited as long as it is a known copolymerization method, and examples include bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization. Solvents that can be used for solution polymerization include toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, propylene glycol monomethyl ether acetate, N-methylpyrrolidone, N,N-dimethylformamide, and γ-butyrolactone. Emulsion polymerization and suspension polymerization typically use water and a surfactant, and copolymerization reactions are carried out with the raw material components emulsified or suspended in water.

[0015] The copolymerization reaction may be radical polymerization, cationic polymerization, or anionic polymerization. In the case of radical polymerization, it is preferable to use a radical polymerization initiator. Specific examples of radical polymerization initiators include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexane-1-carbonnitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, hydrogen peroxide, di-t-butyl peroxide, dicumyl peroxide, dilauroyl peroxide, and benzoyl peroxide. Living radical polymerization, which involves adding free radicals such as TEMPO reagents to form dormant species, is also possible. The compounding amount of the radical polymerization initiator is usually 0.001 to 5 parts by mass with respect to 100 parts by mass of the raw material components of the copolymer. The polymerization temperature is usually 50 to 250 °C, preferably 60 to 200 °C, and the polymerization time is usually 0.5 to 30 hours, preferably 1 to 20 hours. The radical polymerization reaction is preferably carried out under a nitrogen gas atmosphere in order to prevent polymerization inhibition by oxygen in the air.

[0016] Specific examples of the cationic polymerization initiator include inorganic acids such as sulfuric acid and hydrochloric acid, organic acids such as CF3COOH and CCl3COOH, and superacids such as CF3SO3H and HClO4. Specific examples of the anionic polymerization initiator include butyllithium, Na-naphthalene complex, alkali metals, alkyllithium compounds, sodium amide, Grignard reagents, and lithium alkoxides. However, since there is a concern that the ionic initiator used in cationic polymerization or anionic polymerization remains in the copolymer even after the polymerization reaction and has an adverse effect on dielectric properties and insulation, the synthesis of the copolymer as an intermediate raw material of the polymer compound of the present invention is preferably carried out by radical polymerization. The compounding amount of the cationic polymerization initiator or anionic polymerization initiator is usually 0.01 to 5 parts by mass with respect to 100 parts by mass of the raw material components of the copolymer. The polymerization temperature is usually 40 to 150 °C, preferably 50 to 120 °C, and the polymerization time is usually 0.5 to 20 hours, preferably 1 to 15 hours.

[0017] The number average molecular weight of the copolymer serving as an intermediate raw material of the polymer compound of the present invention is usually 3,000 to 300,000, preferably 5,000 to 200,000. In order to obtain a copolymer having a number average molecular weight within the above range, it is preferable to adjust the amount of initiator used in synthesizing the copolymer to an appropriate amount. The amount of initiator necessary to obtain a copolymer having a number average molecular weight within the above range depends on the type of (meth)acrylate having a phenolic hydroxyl group and the amounts of (meth)acrylate having a hydroxyl group, styrene, and N-phenylmaleimide compound used in the copolymerization reaction, and thus cannot be generally stated. However, it is generally known that reducing the amount of initiator results in a copolymer having a larger molecular weight. Therefore, the amount of initiator formulated within the above-described formulated amount range can be selected to obtain a copolymer having a desired molecular weight.

[0018] The use ratios of (meth)acrylate having a phenolic hydroxyl group, styrene, and N-phenylmaleimide compound in synthesizing the copolymer that serves as an intermediate raw material of the high molecular compound of the present invention are not particularly limited. However, the total amount (mass) of styrene and N-phenylmaleimide compound is usually 4 to 99.5 times, preferably 4.5 to 99.7 times, the mass of (meth)acrylate having a phenolic hydroxyl group. The preferred use ratio (mass ratio) of styrene and N-phenylmaleimide compound is usually 99.9:0.1 to 50:50, and preferably 99.8:0.2 to 60:40. By setting the use ratios of (meth)acrylate having a phenolic hydroxyl group, styrene, and N-phenylmaleimide compound, which are raw materials of the copolymer, within the above range, a high molecular compound of the present invention can be obtained in which the cured product exhibits excellent dielectric properties (low dielectric constant and low dielectric tangent).

[0019] The high molecular compound of the present invention is obtained by a dehydrochlorination reaction between the phenolic hydroxyl group of the above copolymer (this hydroxyl group is the hydroxyl group possessed by the (meth)acrylate having a phenolic hydroxyl group as a raw material) and the chloride group of (meth)acrylic acid chloride, or by a dehydration condensation reaction between the phenolic hydroxyl group of the above copolymer and the carboxy group of (meth)acrylic acid.

[0020] The ratio of copolymer to (meth)acrylic acid chloride or (meth)acrylic acid used when synthesizing the polymer compound of the present invention is not particularly limited. However, if there is an excess or deficiency of (meth)acrylic acid chloride or (meth)acrylic acid relative to the phenolic hydroxyl groups of the copolymer, unreacted (meth)acrylic acid chloride or (meth)acrylic acid remaining in the polymer compound, or phenolic hydroxyl groups remaining in the copolymer without reacting with (meth)acrylic acid chloride or meth)acrylic acid, may adversely affect the properties of the cured product. Therefore, it is preferable to use an equivalent amount of (meth)acrylic acid chloride or (meth)acrylic acid to the hydroxyl groups of the copolymer.

[0021] The reaction between the copolymer and (meth)acrylic acid chloride can be carried out by adding (meth)acrylic acid chloride to an organic solvent solution of the copolymer under stirring. The organic solvent that can be used here is not particularly limited as long as it can dissolve the copolymer and (meth)acrylic acid chloride, and if the copolymer used as an intermediate raw material is synthesized in a solvent, the copolymer solution after the polymerization reaction can be used as is. The concentration of the copolymer solution used for the reaction with (meth)acrylic acid chloride is usually 10 to 90% by mass, preferably 20 to 80% by mass. The reaction temperature is usually 30 to 120°C, preferably 40 to 110°C, and the reaction time is usually 0.5 to 4 hours, preferably 1 to 3 hours.

[0022] Since the reaction between the copolymer and (meth)acrylic acid chloride is a dehydrochlorination reaction, it is preferable to add a tertiary amine such as triethylamine or pyridine to the reaction solution beforehand to trap the hydrochloric acid generated and to further promote the reaction. The amount of tertiary amine used is preferably equimolar to 4 times the number of moles of (meth)acrylic acid chloride, and more preferably equimolar to 3 times the number of moles. The hydrochloric acid generated during the reaction precipitates as the hydrochloride salt of the amine and can be removed by filtration after the reaction. Excess tertiary amine can also be removed from the system by heating under reduced pressure after filtration.

[0023] The reaction between the copolymer and (meth)acrylic acid is a conventionally known esterification reaction, and a method for carrying out the reaction is, for example, heating and stirring the copolymer and (meth)acrylic acid in the presence of a catalyst. Since the reaction between the copolymer and (meth)acrylic acid is a dehydration reaction, it is preferable to carry out the reaction while distilling off water from the reaction system by azeotrope, and for this reason, it is preferable to carry out the reaction using solvents such as toluene, xylene, ethyl acetate, butyl acetate, and methyl isobutyl ketone, which do not completely mix with water. The amount of solvent used is preferably such that the concentration of the raw material components of the polymer compound represented by formula (1) is 20 to 80% by mass. Examples of catalysts used in the esterification reaction include acidic catalysts such as sulfuric acid, methanesulfonic acid, and p-toluenesulfonic acid, and the amount used is preferably 0.1 to 5% by mass of the total mass of the raw materials and solvent of the polymer compound represented by formula (1) used in the reaction. The reaction temperature is usually 50 to 150°C, preferably 60 to 140°C, and the reaction time is usually 0.5 to 4 hours, preferably 1 to 3 hours.

[0024] Furthermore, in order to prevent polymerization reactions between (meth)acryloyl groups in the polymer compound of the present invention and to improve the storage stability of the polymer compound, it is preferable to add a small amount of polymerization inhibitor to the polymer compound solution after the synthesis reaction is complete. Specific examples of polymerization inhibitors include hydroquinone, paramethoxyphenol, methylhydroquinone, di-t-butylhydroxytoluene, t-butylhydroquinone, 2-t-butyl-1,4-benzoquinone, 1,4-benzoquinone, 1,1-diphenyl-2-picrylhydrazyl free radical, 6-t-butyl-2,4-xylenol, 4-t-butylpyrocatechol, 2,6-di-t-butylphenol, 2,6-di-t-butyl-p-cresol, and phenothiazine.

[0025] The number-average molecular weight range of the polymer compound obtained in this way is preferably 11,000 to 300,000, more preferably 15,000 to 200,000. If the molecular weight is smaller than the above range, the adhesion to low-roughness copper foil will be low, and if it is larger, the viscosity will be high, which may make coating and other processes difficult. In this specification, molecular weight refers to the value calculated in polystyrene equivalent based on GPC measurement results.

[0026] The resin composition of the present invention contains the polymer compound of the present invention and a radical initiator. Either a thermal radical initiator or a photoradical initiator can be used as the radical initiator. Preferred thermal radical initiators include peroxides such as benzoyl peroxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3, di-t-butyl peroxide, t-butylcumyl peroxide, α,α-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, dicumyl peroxide, di-t-butylperoxyisophthalate, t-butylperoxybenzoate, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, di(trimethylsilyl)peroxide, and trimethylsilyltriphenylsilyl peroxide.

[0027] Examples of preferred photoradical initiators include benzoin, benzoin methyl ether and its alkyl ethers such as benzoin and benzoin ethyl ether; acetophenones such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone and 1,1-dichloroacetophenone; anthraquinones such as 2-methylanthraquinone, 2-amylanthraquinone, 2-t-butylanthraquinone and 1-chloroanthraquinone; thioxanthones such as 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone and 2-chlorothioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone; 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1; acylphosphine oxides and xanthones.

[0028] The amount of radical initiator in the resin composition of the present invention is usually 0.1 to 10 parts by mass, preferably 0.1 to 8 parts by mass, per 100 parts by mass of the total resin components, such as the polymer compound and the radical-reactive compound which is an optional component described later.

[0029] The resin composition of the present invention may also contain a compound having a radical polymerizable group. The compound having a radical polymerizable group that can be used in combination with the resin composition of the present invention may be either a radical polymerizable monomer with a number average molecular weight of approximately less than 1,000 or a radical polymer with a number average molecular weight of approximately 1,000 or more, and both may be used in combination.

[0030] Specific examples of radical polymerizable monomers having radical polymerizable groups include acenaphthylene, N-phenylmaleimide, N-vinyl-2-pyrrolidone, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, neopentyl glycol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, glycerin dimethacrylate, and 2-hydroxy-3-acryloyloxypropylmethacrylate. Relate, ethylene oxide adduct of bisphenol A methacrylate, trimethylolpropane trimethacrylate, tricyclodecane dimethanol dimethacrylate, glycerin dimethacrylate, trimethylolpropane trimethacrylate, ethoxylated isocyanurate triacrylate, ε-caprolactone modified tris-(2-acryloxyethyl) isocyanurate, pentaerythritol triacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, pentaerythritol Diphenyltetraacrylate, dipentaerythritol polyacrylate, dipentaerythritol hexaacrylate, triallyl isocyanurate, triallyl cyanurate, divinylbenzene, divinyl isophthalate, N-phenyl-maleimide, N-phenyl-methylmaleimide, N-phenyl-chloromaleimide, Np-chlorophenyl-maleimide, Np-methoxyphenyl-maleimide, Np-methylphenyl-maleimide, Np-nitrophenyl-maleimide, Np-phenoxyphenyl-maleimide, Np-phenylaminophenyl Nyl-maleimide, Np-phenoxycarbonylphenyl-maleimide, 1-maleimide-4-acetoxysuccinimide-benzene, 4-maleimide-4'-acetoxysuccinimide-diphenylmethane, 4-maleimide-4'-acetoxysuccinimide-diphenyl ether, 4-maleimide-4'-acetamide-diphenyl ether, 2-maleimide-6-acetamide-pyridine, 4-maleimide-4'-acetamide-diphenylmethane, and Np-phenylcarbonylphenyl-maleimide N-ethylmaleimide, N-2.Examples include 6-xylmaleimide, N-cyclohexylmaleimide, N-2,3-xylmaleimide, xylmaleimide, 2,6-xylenemaleimide, and 4,4'-bismaleimidediphenylmethane, but those having a maleimide group as a functional group are preferred. These radical polymerizable monomers may be used individually or in combination of two or more. By using a radically polymerizable monomer in combination with the resin composition of the present invention, the reactivity of the resin composition and the heat resistance of the cured product can be improved. The content of the radical polymerizable monomer in the resin composition of the present invention is usually 50% by mass or less, preferably 2 to 40% by mass, relative to the polymer compound represented by formula (1).

[0031] Specific examples of radical polymerizable polymers (monomers) having radical reactive groups include polyphenylene ether modified with methacryloyl groups at both ends represented by formula (3) below (product name SA-9000, manufactured by Sabic LLC), polyphenylene ether modified with styroiyl groups at both ends represented by formula (4) below (product name OPE-2St, manufactured by Mitsubishi Gas Chemical Company, Inc.), polyfunctional styrene resin represented by formula (5) below (product name STR, manufactured by Nippon Kayaku Co., Ltd.), and styrene-butadiene copolymers. In formulas (3) to (5), n is the average value of the number of repetitions, usually 2 to 100, preferably 4 to 80. The number-average molecular weight of the radical polymer represented by any of formulas (3) to (5) is preferably 1,000 to 3,000. Furthermore, it is also preferable to use a radical polymerizable monomer represented by any of formulas (3) to (5) with a number-average molecular weight of 500 or more and less than 1,000 in combination with the resin composition of the present invention. By using a radical polymerizable polymer in combination with the resin composition of the present invention, the reactivity of the resin composition and the heat resistance of the cured product can be improved. The content of the radical polymerizable polymer in the resin composition of the present invention is usually 80% by mass or less, preferably 5 to 70% by mass, relative to the polymer compound represented by formula (1).

[0032] [ka]

[0033] [ka]

[0034] [ka]

[0035] The resin composition of the present invention may also contain an organic solvent. Specific examples of organic solvents include aromatic solvents such as toluene and xylene, ether-based 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, and anisole, ketone-based solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone and cyclohexanone, lactones such as γ-butyrolactone and γ-valerolactone, amide-based solvents such as N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide and N,N-dimethylimidazolidinone, and sulfones such as tetramethylenesulfone. The content of the organic solvent in the resin composition of the present invention is usually 90% by mass or less, preferably 30 to 80% by mass.

[0036] The resin composition of the present invention may be used in combination with a polymerization inhibitor to improve storage stability. The polymerization inhibitor that can be used in combination is not particularly limited as long as it is generally known, and examples include quinones such as hydroquinone, methylhydroquinone, p-benzoquinone, chloranil and trimethylquinone, aromatic diols, and di-t-butylhydroxytoluene.

[0037] The resin composition of the present invention can be used by adding fillers and additives in amounts that do not impair its original properties, in order to impart desired performance depending on its application. The fillers may be in the form of fibers or powders, and examples include silica, carbon black, alumina, talc, mica, glass beads, glass hollow spheres, etc.

[0038] The resin composition of the present invention may also be used in combination with flame retardant compounds, additives, etc. These are not particularly limited as long as they are commonly used. For example, flame retardant compounds include bromine compounds such as 4,4-dibromoviphenyl, phosphate esters, melamine phosphate, phosphorus-containing epoxy resins, nitrogen compounds such as melamine and benzoguanamine, oxazine ring-containing compounds, and silicon-based compounds. Additives such as ultraviolet absorbers, antioxidants, photopolymerization initiators, fluorescent whitening agents, photosensitizers, dyes, pigments, thickeners, lubricants, defoamers, dispersants, leveling agents, and glossing agents can be used in appropriate combinations as desired.

[0039] The resin composition of the present invention can be used by coating or impregnating various substrates. For example, when a thermal radical initiator is used, the film-like adhesive obtained by coating a PET film, drying the organic solvent as necessary, and then peeling off the PET film can be used as an interlayer insulating layer for a multilayer printed circuit board. The polyimide film having the film-like adhesive obtained by coating a polyimide film and drying the organic solvent as necessary can be used as a coverlay. The copper foil having the film-like adhesive obtained by coating a copper foil and drying the organic solvent as necessary can be used as resin-coated copper foil. Furthermore, by impregnating glass cloth, glass paper, carbon fiber, various nonwoven fabrics, etc., it can be used as a prepreg for printed circuit boards and CFRP. In addition, by using a photoradical initiator, it can be used as various resists.

[0040] The interlayer insulating layer, coverlay, resin-coated copper foil, prepreg, etc. of the present invention can be cured by heating and pressing them using a hot press machine or the like. [Examples]

[0041] 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.

[0042] Example 1 (Synthesis of the polymer compound of the present invention) (Step 1) Synthesis of copolymer 1, which is an intermediate raw material for the polymer compound of the present invention. In a flask equipped with a thermometer, condenser, nitrogen gas inlet tube, and stirrer, 96 parts of styrene, 2 parts of 4-hydroxyphenyl methacrylate, 2 parts of N-phenylmaleimide, 0.122 parts of dilauroyl peroxide, and 25 parts of anisole were added and reacted under a nitrogen atmosphere at 120 to 130°C for 6 hours to obtain an anisole solution of copolymer 1 represented by the following formula (6). Analysis of a portion of this solution by gas chromatography showed that no unreacted 4-hydroxyphenyl methacrylate and N-phenylmaleimide remained. Furthermore, when a portion of this solution was heated under reduced pressure to remove the solvent and unreacted styrene, the amount of copolymer 1 obtained was calculated as 61 parts, and considering that 39 parts were unreacted styrene, the obtained copolymer was a copolymer of 57 parts styrene, 2 parts 4-hydroxyphenyl methacrylate, and 2 parts N-phenylmaleimide. Furthermore, the number-average molecular weight of the sample used for the measurement of the dry mass was 45,000, and the weight-average molecular weight was 172,000. From the copolymerization ratio of styrene and 4-hydroxyphenyl methacrylate and the number-average molecular weight, the value of l in equation (6) was calculated to be 9, the value of m was 397, and the value of n was 8.

[0043] [ka]

[0044] (Step 2) Synthesis of polymer compound 1 of the present invention From the anisole solution of copolymer 1 obtained in step 1, unreacted styrene was removed together with anisole under heating and reduced pressure, and then toluene was added to obtain 244 parts of a 25% by mass solution of copolymer 1. To this solution, 1.48 parts of triethylamine were added, and then 1.17 parts of methacrylate chloride were added and the mixture was reacted at 60°C under stirring for 1 hour. The reaction solution was filtered under pressure using filter paper with a capture particle size of 1 micron to remove triethylamine hydrochloride, and then excess triethylamine and toluene were removed from the filtrate using a rotary vaporizer. The amount of toluene was then adjusted again to obtain 244 parts of a solution containing 25% by mass of the polymer compound of the present invention (polymer compound 1) represented by the following formula (7). The number average molecular weight of the obtained polymer compound 1 was 47,000, and the weight average molecular weight was 178,000.

[0045] [ka]

[0046] Comparative Example 1 (Synthesis of comparative compound) (Step 3) Synthesis of copolymer 2, which is an intermediate raw material for the comparative example compound. A solution of copolymer 2, represented by the following formula (8), was obtained using the same method as in step 1, except that the amount of styrene added was changed to 98 parts and the amount of N-phenylmaleimide added to 0 parts. When a portion of this solution was analyzed by gas chromatography, no unreacted 4-hydroxyphenyl methacrylate remained. Furthermore, when a portion of this solution was heated under reduced pressure to remove the solvent and unreacted styrene, the amount of copolymer 2 obtained by calculating the dry mass as the solid content was 59 parts. Considering that 39 parts were unreacted styrene, the obtained copolymer was a copolymer of 57 parts styrene and 2 parts 4-hydroxyphenyl methacrylate. The number-average molecular weight of the sample used for the measurement of the dry mass was 51,000, and the weight-average molecular weight was 182,000. From the copolymerization ratio of styrene and 4-hydroxyphenyl methacrylate and the number-average molecular weight, the value of m in formula (8) was calculated to be 471 and the value of n was calculated to be 10.

[0047] [ka]

[0048] (Step 4) Synthesis of comparative compounds Except for replacing the anisole solution of copolymer 1 obtained in step 1 with the anisole solution of copolymer 2 obtained in step 3, the same method as in step 2 was used to obtain 242 parts of a solution containing 25% by mass of the comparative compound (polymer compound 2) represented by the following formula (9). The number-average molecular weight of the obtained polymer compound 2 was 53,000, and the weight-average molecular weight was 185,000.

[0049] [ka]

[0050] Example 2 (Preparation of the resin composition of the present invention) To obtain the resin composition 1 of the present invention, 10 parts of a solution of polymer compound 1 obtained in Example 1 were mixed uniformly with 0.05 parts of dicumyl peroxide as a radical initiator.

[0051] Comparative Example 2 (Preparation of a comparative resin composition) Comparative resin composition 1 was obtained in accordance with Example 2, except that the solution of polymer compound 1 obtained in Example 1 was replaced with the solution of polymer compound 2 obtained in Comparative Example 1.

[0052] (Evaluation of dielectric properties and heat resistance of cured resin compositions) The resin composition 1 of the present invention and the resin composition 1 of the comparative example obtained in Example 2 and Comparative Example 2 were applied to a mirror surface of an 18 μm thick copper foil to a thickness of 280 μm using an applicator, and the solvent was dried by heating at 90°C for 10 minutes. The resulting film-like adhesive on the copper foil was heated and cured in a vacuum oven at 180°C for 1 hour, and then the copper foil was removed by immersion in an etching solution. A cured product with a thickness of 70 μm that could be handled as a film was obtained from the film-like adhesive consisting of the resin composition 1 of the present invention and the resin composition 1 of the comparative example, and the dielectric properties were evaluated using the cured product obtained above. The dielectric properties were evaluated by measuring the dielectric constant and dielectric loss tangent at 10 GHz using the cavity resonance method with a network analyzer 8719ET (manufactured by Agilent Technologies). The glass transition temperature of the film was also measured using a TMA (thermomechanical analyzer). The results are shown in Table 1.

[0053] (Evaluation of adhesive strength of cured resin compositions) Using an applicator, the resin composition 1 of the present invention obtained in Example 2 and Comparative Example 2, and the resin composition 1 of the Comparative Example, were applied to a matte surface of a 12 μm thick low-roughness copper foil for high-frequency applications (CF-T4X-SV: manufactured by Fukuda Metal Foil & Powder Co., Ltd.) to a thickness of 50 μm. The solvent was dried by heating at 90°C for 10 minutes to obtain copper foils having a film-like adhesive made of the resin composition. The matte surface of the same copper foil was placed on top of the adhesive surface of the copper foil obtained above, and the two were heated and cured in a vacuum press at a pressure of 3 MPa for 1 hour. The 90° peel strength (adhesion strength) between the copper foils was then measured using an Autograph AGX-50 (manufactured by Shimadzu Corporation). The results are shown in Table 1.

[0054] [Table 1]

[0055] As described above, when the polymer compound of the present invention is cured using a radical initiator, it forms a flexible film and exhibits excellent dielectric properties, adhesion, and heat resistance.

Claims

1. The following formula (1) 【Chemistry 1】 (In the formula, R １ and R ２ Each of these independently represents either a hydrogen atom or a methyl group. ３ , R ４ and R ５ Each of these independently represents a hydrogen atom or an alkyl group. l, m, and n are the average values ​​of the repeating units, each independently ranging from 1 to 2,000. A polymer compound represented by the symbol.

2. A resin composition comprising the polymer compound and radical initiator described in claim 1.

3. The resin composition according to claim 2, further comprising a compound having a radical reactive group.

4. A film-like adhesive comprising the resin composition according to claim 2 or 3.

5. A cured product of the resin composition according to claim 2 or 3.

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