Curable compound, resin composition containing said compound, and cured article

Abstract

Provided is a curable compound which can be thermally cured or photo-cured when used in combination with a radical initiator, is alkali-soluble, can be cured into a cured article having a low dielectric constant and a low dielectric loss tangent, and has high adhesiveness and a high glass transition temperature.　This compound is represented by formula (1). (In formula (1), X's each independently represent a divalent residue obtained by removing a hydroxyl group from a diol; Y's each independently represent a divalent residue of an aliphatic group or an aromatic group; R's each independently represent a hydrogen atom or a methyl group; and n denotes an average value of the number of repeating units and is a real number of 0.1-20.)

Description

Curable compound, resin composition containing the compound, and cured product

[0001] The present invention relates to a compound that can undergo a thermal or photo-curing reaction when used in combination with a radical initiator.

[0002] Epoxy resins, which have high adhesive properties, insulating properties, and heat resistance, have traditionally been widely used in electronic materials such as printed wiring boards. In the resist field, a typical development method involves curing specific areas using a photoinitiator, followed by removal of uncured areas using an alkaline aqueous solution such as TMAH (tetramethylammonium hydroxide). Therefore, resist resins must be soluble in alkaline solutions. Resins obtained by adding acrylic acid to the epoxy groups of multifunctional epoxy resins and then half-esterifying the resulting alcoholic hydroxyl groups with acid anhydrides such as tetrahydrophthalic anhydride are widely used. However, these resins contain large amounts of highly polar carboxylic acids in their molecules, which results in high dielectric loss tangents in the cured products, making them unsuitable for high-frequency applications.

[0003] Japanese Patent Application Laid-Open No. 2001-75274

[0004] Patent Document 1 discloses a compound obtained by reacting a tetracarboxylic dianhydride having a specific structure with a diol compound and a (meth)acrylate having one hydroxyl group in the molecule, as a novel alkali-soluble curable resin. However, the cured products of these polymer compounds have low heat resistance, such as a low glass transition temperature, and furthermore, the high proportion of carboxylic acid in the polymer compounds results in a high dielectric loss tangent, making them unsuitable for recent high-frequency applications that require a low dielectric loss tangent.

[0005] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a curable compound that is soluble in an alkaline aqueous solution, and that has a low dielectric constant and dielectric dissipation factor when cured, and that has high heat resistance and high adhesive strength.

[0006] That is, the present invention includes the following [1] to [5]. In this specification, "(numerical value 1) to (numerical value 2)" indicates that the upper and lower limits are included. [1] A compound represented by the following formula (1):

[0007]

[0008] (In formula (1), each X independently represents a divalent residue obtained by removing a hydroxyl group from a diol. Each Y independently represents a divalent residue of an aliphatic group or an aromatic group. Each R independently represents a hydrogen atom or a methyl group. n represents the average number of repeating units and is a real number from 0.1 to 20.) [2] The compound according to the preceding item [1], wherein the diol is a dimer diol. [3] A resin composition comprising the compound according to the preceding item [1] or [2] and a radical initiator. [4] The resin composition according to the preceding item [3], which contains a radical-reactive monomer having one or more functional groups per molecule. [5] A cured product of the resin composition according to either the preceding item [3] or [4].

[0009] The compound according to the present invention and a composition containing the compound are soluble in an alkaline aqueous solution and can be cured by using a radical initiator in combination with the compound and applying heat or light energy. The cured product of the composition can provide a compound having excellent dielectric properties, heat resistance, and adhesiveness.

[0010] The compound of the present invention is represented by the following formula (1).

[0011]

[0012] In formula (1), each X independently represents a divalent residue obtained by removing a hydroxyl group from a diol. Each Y independently represents a divalent residue of an aliphatic group or an aromatic group (a group obtained by removing one hydrogen atom from an aliphatic group or an aromatic group, or a group obtained by removing two hydrogen atoms from an aliphatic compound or an aromatic compound). Each R independently represents a hydrogen atom or a methyl group. n represents the average number of repeating units and is preferably a real number from 0.1 to 20, more preferably a real number from 0.5 to 10. A polymer compound in which the number of repeating units is a real number of 2 or more is preferred.

[0013] The value of n in formula (1) can be determined by GPC (gel permeation chromatography) measurement.

[0014] The method for producing the compound represented by formula (1) above is not particularly limited, but it can be obtained, for example, as follows: 1 mole of 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride is subjected to an addition reaction with less than 1 mole of diol to obtain an intermediate. The carboxylic acid anhydride groups present at the terminal of the obtained intermediate are reacted with an equimolar amount of (meth)acrylate having one hydroxyl group per molecule to convert all the acid anhydride groups to carboxylic acids and esters, thereby obtaining the polymer compound represented by formula (1) above.

[0015] Preferred diols include ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 1,5-pentanediol, 1,9-nonanediol, 1,4-hexanedimethanol, polyethylene glycol, 1,16-hexadecanediol, 1,17-heptadecanediol, 1,18-octadecanediol, 1,20-eicosanediol, and dimer diols having 36 carbon atoms, with dimer diols being particularly preferred from the viewpoint of improving the dielectric properties of the compound of the present invention. Dimer diols include those in which the double bonds derived from the unsaturated fatty acid raw material remain intact and those in which they are hydrogenated, with the hydrogenated dimers being preferred from the viewpoint of preventing deterioration of the dielectric properties due to oxidation of the double bonds.

[0016] The dimer diols are obtained by converting the two carboxyl groups of a dimer acid, which is a dimer of an unsaturated fatty acid such as oleic acid, into primary hydroxyl groups. Non-limiting general formulas of dimer diols are shown below (in each formula, m+n preferably equals 6 to 17, and p+q preferably equals 8 to 19, and the dashed lines represent carbon-carbon single bonds or carbon-carbon double bonds).

[0017]

[0018] Preferred (meth)acrylates having one hydroxyl group per molecule include 2-hydroxymethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, hydroquinone mono(meth)acrylate, cyclohexane mono(meth)acrylate, etc. In the formula (1), Y is a residue obtained by removing the hydroxyl group and the (meth)acrylate group from a (meth)acrylate having one hydroxyl group per molecule.

[0019] The intermediate of the compound of formula (1) is represented by the following formula (2), and can be obtained by adding less than 1 mole of a diol compound to 1 mole of 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride and carrying out a half-esterification reaction.

[0020]

[0021] In formula (2), X and n have the same meanings as in formula (1).

[0022] The amount of the diol compound used as a raw material in the above reaction is preferably 0.4 to 0.95 moles per mole of 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, and more preferably 0.5 to 0.9 moles. A solvent is preferably used during the reaction. Usable solvents include toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and γ-butyrolactone. The amount of solvent used is preferably 0 to 300% by mass, more preferably 20 to 200% by mass, based on the solid content. A catalyst may also be used to expedite the reaction. Examples of catalysts that can be used include, in addition to pyridine and dimethylaminopyridine, quaternary ammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide, tetraethylammonium chloride, tetraethylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium bromide, benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, benzyltriethylammonium chloride, benzyltriethylammonium bromide, benzyltripropylammonium chloride, benzyltripropylammonium bromide, benzyltrimethylphosphonium chloride, benzyltrimethylphosphonium bromide, benzyltriethylphosphonium chloride, benzyltriethylphosphonium bromide, benzyltripropylphosphonium chloride, benzyltripropylphosphonium bromide, tetraphenylphosphonium chloride, and tetraphenylphosphonium bromide. The amount of catalyst used is preferably 0.001 to 1%, and more preferably 0.005 to 0.5%, of the total mass of the reaction substrates.

[0023] With regard to the ratio of 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride to diol compound, the higher the ratio of diol compound, the higher the average molecular weight of the polymer intermediate; the lower the ratio, the lower the average molecular weight; however, both terminal residues of the intermediate always become acid anhydrides. The reaction temperature is usually 20 to 150°C, preferably 30 to 140°C, and the reaction time is usually 0.5 to 30 hours, preferably 1 to 20 hours. The reaction is terminated when the molecular weight, as determined by GPC (gel permeation chromatography), no longer increases from a certain value.

[0024] Next, a (meth)acrylate having one hydroxyl group per molecule is added to the intermediate and subjected to an addition reaction with the acid anhydride group present in the intermediate, thereby obtaining a compound of formula (1). The amount of (meth)acrylate having one hydroxyl group per molecule used is preferably an equimolar amount relative to one mole of acid anhydride group present in the system, i.e., twice the difference in moles between 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride and the diol compound used in the polymerization reaction, which is the synthesis step of the intermediate. One method for obtaining the compound of formula (1) includes adding a (meth)acrylate having one hydroxyl group per molecule to a reaction solution of the intermediate described above and stirring the mixture to allow the reaction to proceed. The reaction temperature is preferably 50 to 120°C, and the reaction time is preferably 1 to 20 hours.

[0025] The resin composition of the present invention contains the compound of formula (1) and a radical initiator. As the radical initiator, a thermal radical initiator or a photoradical initiator can be used. 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)hexyne-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.

[0026] Examples of preferred photoradical initiators include benzoin and its alkyl ethers such as benzoin, benzoin methyl ether, and benzoin ethyl ether; acetophenones such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, and 1,1-dichloroacetophenone; anthraquinones such as anthraquinone, 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 phenone, 4,4'-bis(diethylamino)benzophenone, and 4,4'-bis(dimethylamino)benzophenone; 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1-one; acylphosphine oxides and xanthones; oxime esters such as 1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(o-benzoyloxime), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime).

[0027] The content of the 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 of the resin components such as the compound of formula (1) and the optional radical-reactive monomer described below.

[0028] The resin composition of the present invention may contain a radical reactive monomer in combination. By using a radical reactive monomer in combination, the reactivity of the resin composition of the present invention and the heat resistance of the cured product can be improved. The radical reactive monomer is preferably one having one or more functional groups, and specific examples thereof 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, glycerin dimethacrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, ethylene oxide adduct methacrylate of bisphenol A, trimethylolpropane trimethacrylate, tricyclodecane dimethanol dimethacrylate, glycerin dimethacrylate, trimethylolpropane trimethacrylate, ethoxylated isocyanuric acid triacrylate, ε-caprolactone-modified tris-(2-acryloxyethyl)isocyanuric acid acrylate, pentaerythritol triacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol polyacrylate, dipentaerythritol hexaacrylate, triallyl isocyanurate, triallyl cyanurate, divinylbenzene, divinyl isophthalate, N-phenyl-maleimide, N-phenyl-methylmaleimide, N-phenyl-chloromaleimide, N 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-maleimido-4-acetoxysuccinimide-benzene, 4-maleimido-4'-acetoxysuccinimide-diphenylmethane, 4-maleimido-4'-acetoxysuccinimide -diphenyl ether, 4-maleimido-4'-acetamido-diphenyl ether, 2-maleimido-6-acetamido-pyridine, 4-maleimido-4'-acetamido-diphenylmethane, and N-p-phenylcarbonylphenyl-maleimide N-ethylmaleimide, N-2,6-xylylmaleimide, N-cyclohexylmaleimide, N-2,3-xylylmaleimide, xylylmaleimide, 2,6-xylenemaleimide, and 4,4'-bismaleimidediphenylmethane. These radical reactive monomers may be used alone or in combination of two or more.

[0029] The resin composition of the present invention may be used in combination with a radical-reactive polymer. By using a radical-reactive polymer in combination, the adhesiveness of the resin composition of the present invention and the heat resistance of the cured product can be improved. The radical-reactive polymer is preferably one having two or more functional groups, and specific examples thereof include a copolymer of styrene and butadiene, a modified polyphenylene ether resin, and an imide-extended bismaleimide.

[0030] The styrene and butadiene copolymer may be a random copolymer (commonly known as SBR) or a block copolymer. Alternatively, a copolymer in which the double bonds derived from butadiene in the block copolymer are hydrogenated to form saturated hydrocarbons (commonly known as SEBS resin) may also be used. The ratio of styrene to butadiene in the polymer is typically 10:90 to 90:10. The number average molecular weight is typically 1,000 to 100,000. Commercially available SBR products include Ricon 100, Ricon 181, and Ricon 184 from Cray Valley Corporation, and commercially available SEBS resin products include the Tuftec series from Asahi Kasei Corporation and the G Polymer series from Kraton Corporation.

[0031] Preferred examples of modified polyphenylene ether resins include those having methacryloyl groups, acryloyl groups, or vinyl groups at both molecular terminals and having a number average molecular weight of 1,000 to 10,000. Specific examples include a compound represented by the following formula (3) (product name: SA9000, manufactured by SABIC Japan LLC) having methacryloyl groups at both terminals and a number average molecular weight of about 1,700, and a compound represented by the following formula (4) (product name: OPE-2St 1200 or OPE-2St 2200, manufactured by Mitsubishi Gas Chemical Company, Inc.) having vinyl groups at both terminals and a number average molecular weight of about 1,200 or 2,200.

[0032]

[0033]

[0034] The imide-extended bismaleimide resin used in the present invention can be obtained by a known method, such as that described in Japanese Patent Publication No. 5328006. Specifically, the resin can be obtained by carrying out a dehydration condensation reaction of an aliphatic diamine and an aromatic or aliphatic tetracarboxylic dianhydride in an organic solvent using an acid catalyst in a molar ratio such that the aliphatic diamine is in excess, followed by dehydration condensation of amino groups present at the polymer terminals with maleic anhydride, and then removing the catalyst by washing with water.

[0035] Specific examples of aliphatic diamines include 1,10-diaminodecane, 1,12-diaminododecane, dimer 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-diaminomenthane, 1,8-diaminooctane, 1,9-diaminononane, 3,3'-diamino-N-methyldipropylamine, diaminomaleonitrile, 1,3-diaminopentane, and 9,10-diaminophenanthrene, with dimer diamine being particularly preferred.

[0036] Specific examples of aromatic or aliphatic tetracarboxylic dianhydrides include pyromellitic anhydride, 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'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, and 4,4'-bisphenol A. Diphthalic anhydride, 5-(2,5-dioxytetrahydro)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, ethylene glycol bis(trimellitic anhydride), hydroquinone diphthalic anhydride, 1,2,3,4-cyclobutane tetracarboxylic dianhydride (CBDA), 1,2-dimethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride, 1,2,4,5-cyclohexane tetracarboxylic dianhydride, 1,1'-bicyclohexane-3,3',4,4'-tetracarboxylic dianhydride Examples of suitable dianhydrides include tetracarboxylic acid-3,4:3',4'-dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, 2,3,4,5-tetrahydrofuran tetracarboxylic acid dianhydride, and 3,5,6-tricarboxy-2-norbornane acetic acid dianhydride, with pyromellitic anhydride and 1,2,4,5-cyclohexane tetracarboxylic acid dianhydride being particularly preferred. Commercially available products include BMI-3000 from Designer Molecules, Inc.

[0037] In addition, since the compound of formula (1) is soluble in alkali, it can be used in combination with a conventional alkali-soluble curable resin. Specific examples of alkali-soluble curable resins include those obtained by subjecting the epoxy groups of a polyfunctional epoxy resin to an addition reaction with acrylic acid, and then reacting the resulting alcoholic hydroxyl groups with a polybasic acid anhydride to form half esters.

[0038] Examples of polyfunctional epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, aralkylphenol novolac epoxy resins, biphenyl novolac epoxy resins, triphenylmethane epoxy resins, etc. Examples of the polybasic acid anhydrides include dibasic acid anhydrides such as maleic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and chlorendic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, and biphenyltetracarboxylic anhydride.

[0039] The resin composition of the present invention may contain an organic solvent. Specific examples of the organic solvent 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-dimethylimidazolidinone, and sulfones such as tetramethylene sulfone. The content of the organic solvent in the resin composition of the present invention is typically 90% by mass or less, preferably 30 to 80% by mass, based on the resin composition.

[0040] 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 a commonly known polymerization inhibitor, and examples thereof include quinones such as hydroquinone, methylhydroquinone, p-benzoquinone, chloranil, and trimethylquinone, aromatic diols, and di-t-butylhydroxytoluene.

[0041] The resin composition of the present invention can be blended with fillers and additives in amounts that do not impair the inherent performance, in order to impart desired performance depending on the application. The fillers may be in the form of fibers or powders, and examples of such fillers include silica, carbon black, alumina, talc, mica, glass beads, and glass hollow spheres.

[0042] The resin composition of the present invention can also contain flame-retardant compounds, additives, and the like. These compounds are not particularly limited as long as they are commonly used. For example, flame-retardant compounds include bromine compounds such as 4,4-dibromobiphenyl, phosphate esters, melamine phosphate, phosphorus-containing epoxy resins, nitrogen compounds such as melamine and benzoguanamine, oxazine ring-containing compounds, and silicon-based compounds. Additives include ultraviolet absorbers, antioxidants, photopolymerization initiators, fluorescent brighteners, photosensitizers, dyes, pigments, thickeners, lubricants, antifoaming agents, dispersants, leveling agents, and gloss agents, and these can be used in appropriate combinations as desired.

[0043] The resin composition of the present invention can be applied to or impregnated into various substrates and used. For example, when a thermal radical initiator is used, the resin composition can be applied to a PET film to form an interlayer insulating layer for a multilayer printed circuit board, to a polyimide film to form a coverlay, or to a copper foil to form a resin-coated copper foil by coating and drying it. Furthermore, by impregnating glass cloth, glass paper, carbon fiber, various nonwoven fabrics, etc., the resin composition can be used to form printed wiring boards or CFRP prepregs. Furthermore, when a photoradical initiator is used, only the areas irradiated with light of a specific wavelength are cured, and the remaining areas are washed with an alkaline aqueous solution, allowing the development of specific patterns. This allows the resin composition to be used as various resists, such as rewiring layers for semiconductors and solder resists for printed circuit boards.

[0044] The interlayer insulating layer, coverlay, resin-coated copper foil, prepreg, etc. of the present invention can be heated and pressure-molded using a hot press or the like to form a cured product.

[0045] The present invention will be described in more detail below with reference to examples and comparative examples. Unless otherwise specified, parts and percentages are by mass and percentages by mass, respectively. However, the present invention is not limited to these examples.

[0046] Example 1 (Synthesis of Compound of the Present Invention) 20.18 parts of hydrogenated dimer diol (product name Pripol 2033, manufactured by Cargill), 26.0 parts of 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, 50 parts of propylene glycol monomethyl ether acetate (PGMEA), and 0.05 parts of pyridine were added to a flask equipped with a thermometer, a condenser, a nitrogen gas inlet tube, and a stirrer, and the mixture was allowed to react at 130°C for 3 hours to obtain a PGMEA solution of intermediate 1 containing a compound represented by formula (5): Since dimer diol is a mixture, it may also contain compounds with different structures derived from dimer diol. The value of n calculated from the number average molecular weight of 2900 obtained by GPC was 2.2.

[0047]

[0048] The temperature of the solution of Intermediate 1 was lowered to 110°C, and 3.25 parts of 2-hydroxyethyl methacrylate was added while bubbling air into the system. The reaction was allowed to proceed at 110°C for 10 hours. The temperature of the system was then lowered to room temperature, 100 parts of methanol was added, and the mixture was stirred. The mixture was then allowed to stand to precipitate a polymer. The upper methanol layer was decanted to remove pyridine and traces of unreacted low-molecular-weight compounds. An additional 50 parts of PGMEA was added to the lower PGMAE layer, and the methanol dissolved in the system was removed by evaporation. The amount of PGMEA was adjusted to obtain 127 parts of a 35% PEMGEA solution of a compound represented by formula (6) below. Because dimer diol is a mixture, it may also contain compounds with different structures derived from dimer diol. The acid value of the compound of formula (6) was measured and found to be 114 mgKOH / g.

[0049]

[0050] Comparative Example 1 (Synthesis of Comparative Compound) The same procedure as in Example 1 was carried out, except that 10.9 parts of pyromellitic anhydride was used instead of 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, to obtain a PGMEA solution of intermediate 2 containing a compound represented by the following formula (7). Since dimer diol is a mixture, it may also contain compounds with different structures derived from dimer diol. The value of n calculated from the number average molecular weight of 2,000 obtained by GPC was 2.4.

[0051]

[0052] The temperature of the solution of intermediate 2 was lowered to 110°C, and 3.25 parts of 2-hydroxyethylene methacrylate was added while bubbling air into the system. The reaction was allowed to proceed at 110°C for 10 hours. The temperature of the system was then lowered to room temperature, 100 parts of methanol was added, and the mixture was stirred. The mixture was then allowed to stand to precipitate a polymer. The upper methanol layer was decanted to remove pyridine and traces of unreacted low-molecular-weight compounds. An additional 50 parts of PGMEA was added to the lower PGMAE layer, and the methanol dissolved in the system was removed by evaporation. The amount of PGMEA was adjusted to obtain 87 parts of a 35% PEMGEA solution of a compound represented by formula (8) (comparative compound). Because dimer diol is a mixture, it may also contain compounds with different structures derived from dimer diol. The acid value of the compound of formula (8) was measured and found to be 167 mgKOH / g.

[0053]

[0054] [Example 2, Comparative Example 2] (Evaluation of Alkali Solubility) 0.16 parts of each of the resin solutions obtained in Example 1 and Comparative Example 1 was placed in a 20 ml sample tube, left at 130°C for 30 minutes to completely evaporate the solvent, and then 10 ml of a 2.38% aqueous solution of TMAH (tetramethylammonium hydroxide) was added and the time until complete dissolution was measured. Table 1 shows the dissolution times of the resin solutions of Example 1 and Comparative Example 1.

[0055]

[0056] [Example 3, Comparative Example 3 (Preparation of Resin Compositions)] 0.08 parts of dicumyl peroxide as a radical initiator was added to 10 parts of the resin solution obtained in Example 1 and Comparative Example 1, respectively, and the mixture was mixed uniformly to obtain Resin Composition 1 and Resin Composition 2 (for comparison).

[0057] (Evaluation of Dielectric Properties, Heat Resistance, and Adhesion of Cured Resin Compositions) Resin compositions 1 and 2 obtained in Example 3 and Comparative Example 3 were applied to the mirror surface of 18 μm-thick copper foil to a thickness of 140 μm using an applicator. The coating was then heated at 90°C for 10 minutes to dry off the solvent, yielding copper foil bearing a film-like adhesive made of the resin composition. The film-like adhesive on the copper foil thus obtained was then cured by heating at 180°C for 1 hour in a vacuum oven, and then immersed in an etching solution to remove the copper foil, yielding a 70 μm-thick cured film-like adhesive that could be handled as a film. The dielectric constant and dielectric loss tangent of the cured product at 10 GHz were measured by cavity resonance using a network analyzer 8719ET (Agilent Technologies). The glass transition temperature of the same sample was also measured using a thermomechanical analyzer (TMA). The results are shown in Table 2.

[0058] Resin compositions 1 and 2 were each applied to a 50 μm thickness on the matte side of a 12 μm-thick, low-roughness copper foil for high frequency applications (CF-T4X-SV, manufactured by Fukuda Metal Foil & Powder Co., Ltd.) using an applicator. The solvent was then dried off by heating at 90°C for 10 minutes, yielding a copper foil bearing a film-like adhesive made from the resin composition. The matte side of the same copper foil as above was then placed on the adhesive side of the resin-coated copper foil obtained above, and the resulting foil was 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 2.

[0059]

[0060] As described above, the compound of formula (1) exhibits good solubility in an alkaline aqueous solution, and the composition thereof exhibits excellent dielectric properties, heat resistance, and adhesiveness when cured using a radical initiator.

Claims

1. A compound represented by the following formula (1): (In formula (1), each X independently represents a divalent residue obtained by removing a hydroxyl group from a diol. Each Y independently represents a divalent residue of an aliphatic group or an aromatic group. Each R independently represents a hydrogen atom or a methyl group. n is the average number of repeating units and is a real number from 0.1 to 20.) 2. The compound of claim 1, wherein the diol is a dimer diol.

3. A resin composition comprising the compound according to claim 1 or 2 and a radical initiator.

4. The resin composition according to claim 3, which contains a radical reactive monomer having one or more functional groups in one molecule.

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

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