Soluble polyfunctional vinyl aromatic copolymer, method for producing same, curable resin composition, and cured product thereof

Abstract

Provided is a soluble polyfunctional vinyl aromatic copolymer which is capable of providing a cured resin or molded article having improved dielectric properties, heat resistance, adhesion reliability to a high-temperature production process, resin fluidity, and a linear expansion coefficient. The invention discloses a soluble multifunctional vinyl aromatic copolymer, a manufacturing method thereof and a resin composition thereof. The soluble polyfunctional vinyl aromatic copolymer contains a structural unit derived from a divinyl aromatic compound (a) and a structural unit derived from a monovinyl aromatic compound (b), and the copolymer contains a vinyl group and a 1, 3-divinyl group. The two structural units of 1, 2-substituted ethylene are used as unsaturated functional groups, the number of the unsaturated functional groups is within a specific range, and the functional group equivalent of the number of the functional groups of the 1, 2-substituted ethylene is equal to or greater than a predetermined value.

Description

Technical Field

[0001] The present invention relates to a novel soluble polyfunctional vinyl aromatic copolymer having excellent heat resistance, solubility, moldability, and long-term adhesion reliability, a method for producing the same, and a curable composition containing the copolymer. Further, it relates to a film composed of the curable composition, a cured product obtained by curing, a curable composite material composed of the curable composition and a substrate, a laminate composed of the cured product and a metal foil, and a copper foil with a resin. Background Art

[0002] In recent years, with the increase in information communication volume, high-frequency information communication has become prevalent. For more excellent electrical characteristics, especially to reduce transmission loss in the high-frequency band, an electrical insulating material having a low dielectric constant and a low dielectric loss tangent is required. In addition, printed circuit boards or electronic components using these electrical insulating materials are exposed to high-temperature reflow soldering during installation, so a material with high heat resistance, that is, a high glass transition temperature, is desired. In particular, recently, due to environmental problems, lead-free solders with a high melting point are used, so the demand for electrical insulating materials with higher heat resistance has increased. In response to these demands, curable resins using vinyl-based compounds having various chemical structures have been proposed in the past.

[0003] As such a vinyl-based compound, Patent Document 1 discloses a soluble polyfunctional vinyl aromatic copolymer obtained by polymerizing a divinyl aromatic compound and a monovinyl aromatic compound in an organic solvent at a temperature of 20 to 100°C in the presence of a Lewis acid catalyst and an initiator having a specific structure such as 1-chloroethylbenzene, 1-bromoethylbenzene, and bis(1-chloro-1-methylethyl)benzene. Further, Patent Document 2 discloses a method for producing a soluble polyfunctional vinyl aromatic copolymer having a controlled molecular weight distribution by subjecting a monomer component containing 20 to 100 mol% of a divinyl aromatic compound to cationic polymerization at a temperature of 20 to 120°C in the presence of a quaternary ammonium salt, a Lewis acid catalyst, and an initiator having a specific structure.

[0004] The soluble polyfunctional vinyl aromatic copolymer obtained by the techniques disclosed in these two patent documents has excellent solvent solubility, and the cured product obtained by using the copolymer exhibits excellent physical properties with high heat resistance having a high glass transition temperature. However, the soluble polyfunctional vinyl aromatic copolymer polymerized by the methods disclosed in Patent Document 1 and Patent Document 2 contains a large amount of highly polar impurities brought by catalysts such as chlorine in the product, so it is not sufficient from the viewpoint of dielectric properties. In addition, there is a concern about adverse phenomena such as circuit peeling caused by chlorine impurities in a humid and hot environment.

[0005] In Patent Document 3, a copolymer obtained by a polymerization method is described. In this polymerization method, a Lewis base compound is incorporated together with a divinyl aromatic compound and a monovinyl aromatic compound into an oxygen-containing acid catalyst that selectively generates vinylidene. However, when the vinyl-based compound obtained by this method is exposed to a high process temperature, problems such as a decrease in the adhesion strength between the circuit layer and the resin layer and circuit peeling sometimes occur.

[0006] Patent Document 4 discloses a soluble polyfunctional vinyl aromatic copolymer containing a divinyl aromatic compound, styrene, and a monovinyl aromatic compound other than styrene, and having a specific end group structure within a certain range. However, although the soluble polyfunctional vinyl aromatic copolymer obtained by this method exhibits excellent physical properties such as heat resistance, compatibility, dielectric properties, and damp heat reliability, no studies have been conducted on resin fluidity, the coefficient of linear expansion near the use environment temperature, and adhesion after exposure to a high temperature and high humidity environment.

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: Japanese Patent No. 4338951

[0010] Patent Document 2: Japanese Patent No. 4717358

[0011] Patent Document 3: Japanese Patent No. 6833723

[0012] Patent Document 4: Japanese Patent No. 7126493 Summary of the Invention

[0013] As described above, as a high-end insulating material for circuit boards, the existing vinyl-based compounds are not sufficient in terms of dielectric properties, heat resistance, adhesion reliability to high-temperature manufacturing processes, resin fluidity, and coefficient of linear expansion.

[0014] In view of the above problems, the present invention provides a soluble polyfunctional vinyl aromatic copolymer having excellent dielectric properties, heat resistance, adhesion reliability to high-temperature manufacturing processes, resin fluidity, and coefficient of linear expansion, a method for producing the same, and a curable composition containing the copolymer. In addition, the present invention relates to a film composed of the curable composition, a cured product obtained by curing, a curable composite material composed of the curable composition and a substrate, a laminate composed of the cured product and a metal foil, and a copper foil with resin.

[0015] In view of the above problems, the present inventors have found that a polyfunctional vinyl aromatic copolymer having a specific structure is a preferred material.

[0016] That is, the present invention relates to a soluble polyfunctional vinyl aromatic copolymer, which is characterized in that it is a polyfunctional vinyl aromatic copolymer containing structural units derived from a divinyl aromatic compound (a) and structural units derived from a monovinyl aromatic compound (b). The structural units derived from the divinyl aromatic compound (a) have a vinyl-containing unit represented by the following formula (a1), a 1,2-substituted ethylene-containing unit represented by the following formula (ta2), a crosslinked structural unit represented by the following formula (a2), and a structural unit containing both vinyl and 1,2-substituted ethylene represented by the following formula (ta1). The structural units derived from the monovinyl aromatic compound (b) have a structural unit represented by the following formula (b1) and a terminal unit containing 1,2-substituted ethylene represented by the following formula (tb1). The total number of unsaturated bond functional groups in one molecule (excluding the unsaturated bond groups of the aromatic ring) is 2.1 or more and less than 3.5. The functional group equivalent of the number of functional groups of 1,2-substituted ethylene derived from the following formulas (ta1), (ta2), and (tb1) is 1000 g / eq. or more. The number-average molecular weight is 300 to 10,000, and the molecular weight distribution (Mw / Mn) represented by the ratio of the weight-average molecular weight to the number-average molecular weight is 50 or less. The above-mentioned soluble polyfunctional vinyl aromatic copolymer is soluble in toluene, xylene, tetrahydrofuran, dichloroethane, or chloroform and does not contain halogen-based elements other than fluorine as impurities at 1 ppm or more.

[0017]

[0018] In the formula, R 1 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms.

[0019]

[0020] In the formula, R 1 has the same meaning as in formula (a1).

[0021]

[0022] In the formula, R 1 has the same meaning as in formula (a1).

[0023]

[0024] In the formula, R 1 has the same meaning as in formula (a1).

[0025]

[0026] In the formula, R 2 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms, and R 3 represents hydrogen or a hydrocarbon group having 1 to 12 carbon atoms.

[0027]

[0028] In the formula, R 2 and R 3 have the same meaning as in formula (b1).

[0029] By using the soluble polyfunctional vinyl aromatic copolymer obtained by the present invention, a resin cured product or a molded article capable of improving dielectric properties, heat resistance, adhesion reliability to a high-temperature manufacturing process, resin fluidity, and coefficient of linear expansion can be obtained. In addition, the present invention can also provide a film composed of the novel curable resin composition, a cured body obtained by curing the film, a curable composite material composed of the above curable resin composition and a substrate, a cured body thereof, a laminate composed of the cured body and a metal foil, and a copper foil with resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It shows the 1 1H-NMR spectrum of the copolymer obtained in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0031] Next, the soluble polyfunctional vinyl aromatic copolymer of the present invention will be described in detail. The soluble polyfunctional vinyl aromatic copolymer of the present invention is composed of a structural unit derived from a divinyl aromatic compound (a) and a structural unit derived from a monovinyl aromatic compound (b). The structural unit derived from the divinyl aromatic compound (a) has a vinyl-containing unit represented by the following formula (a1), a 1,2-substituted ethylene-containing unit represented by the following formula (ta2), a crosslinked structural unit represented by the following formula (a2), and a structural unit containing both vinyl and 1,2-substituted ethylene represented by the following formula ((ta1). The structural unit derived from the monovinyl aromatic compound (b) has a structural unit represented by the following formula (b1) and a terminal unit containing 1,2-substituted ethylene represented by the following formula (tb1).

[0032]

[0033] In the formula, R 1 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms.

[0034]

[0035] In the formula, R 1 has the same meaning as in formula (a1).

[0036]

[0037] In the formula, R 1It has the same meaning as formula (a1).

[0038]

[0039] In the formula, R 1 It has the same meaning as formula (a1).

[0040]

[0041] In the formula, R 2 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms, and R 3 represents hydrogen or a hydrocarbon group having 1 to 12 carbon atoms.

[0042]

[0043] In the formula, R 2 and R 3 have the same meaning as formula (b1).

[0044] The soluble polyfunctional vinyl aromatic copolymer of the present invention is characterized in that the total number of unsaturated bond functional groups in one molecule is 2.1 or more and less than 4.0. Among them, the total number of unsaturated bond functional groups does not include the unsaturated bond groups constituting the aromatic ring. The unsaturated bond functional groups include the vinyl groups contained in the above formulas (a1) and (ta1) and 1,2-substituted ethylene groups derived from (ta1), (ta2), and (tb1).

[0045] The number of unsaturated bond functional groups can be obtained by the following (Mathematical formula 1). Here, the number-average molecular weight is the value measured by GPC, and the vinyl equivalent is the value obtained by measuring the iodine value based on the Wijs method.

[0046] Number of unsaturated bond functional groups = number-average molecular weight / vinyl equivalent ··· (Mathematical formula 1)

[0047] When the number of unsaturated bond functional groups in one molecule is less than 2.1, when curing the copolymer in the processing step, the coefficient of linear expansion becomes high due to insufficient crosslinking points. On the other hand, when the number of unsaturated bond functional groups exceeds 4.0, unsaturated bonds remain after curing the copolymer in the processing step, and the thermal history of the processing step causes deterioration, which has an adverse effect on the physical properties.

[0048] The number of unsaturated bond functional groups in one molecule is preferably 2.2 to 3.8, more preferably 2.4 to 3.6.

[0049] Among the unsaturated bond functional groups, in particular, the 1,2-substituted ethylene groups derived from (ta1), (ta2), and (tb1) have low reactivity, so they are likely to remain after the curing treatment in the processing step. If the 1,2-substituted ethylene groups remain, it will cause deterioration. The proportion of the 1,2-substituted ethylene groups can be expressed as the functional group equivalent of the 1,2-substituted ethylene groups, and the functional group equivalent of the 1,2-substituted ethylene groups can be obtained from the number of unsaturated bond functional groups obtained by the above (Mathematical Formula 1) and the proportion of the 1,2-substituted ethylene groups in the unsaturated bonds obtained by 1 HNMR and the above number-average molecular weight according to the following (Mathematical Formula 2).

[0050] Functional group equivalent of 1,2-substituted ethylene groups =

[0051] Number-average molecular weight / (Number of unsaturated bond functional groups × Proportion of 1,2-substituted ethylene groups)

[0052] ···(Mathematical Formula 2)

[0053] In order not to cause the above-mentioned adverse phenomena, the functional group equivalent of the 1,2-substituted ethylene groups is 1000 g / eq. or more. Preferably it is 2000 or more, and more preferably it is 2500 or more.

[0054] In each of the formulas (a1), (a2), (ta1), and (ta2), R 1 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms. However, since they are derived from the divinyl aromatic compound (a), they can be understood according to its description. Specifically, R 1 is preferably an aromatic hydrocarbon group having 6 to 12 carbon atoms, and more preferably a phenylene group, a biphenylene group, or a naphthylene group. In the formula (b1) and the formula (tb1), R 2 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms, and R 3 represents hydrogen or a hydrocarbon group having 1 to 12 carbon atoms. Specifically, R 2 is preferably an aromatic hydrocarbon group having 6 to 12 carbon atoms, and more preferably a phenylene group, a biphenylene group, or a naphthylene group. R 3 is preferably hydrogen or a saturated hydrocarbon group having 1 to 12 carbon atoms, more preferably hydrogen or a saturated hydrocarbon group having 1 to 6 carbon atoms, and further preferably hydrogen or a saturated hydrocarbon group having 1 to 3 carbon atoms.

[0055] The Mn of the soluble polyfunctional vinyl aromatic copolymer of the present invention (where Mn is the number average molecular weight in terms of standard polystyrene measured by gel permeation chromatography) is from 300 to 10,000. If Mn is less than 300, the amount of the monofunctional copolymer contained in the copolymer increases, so the heat resistance of the cured product decreases. On the other hand, if Mn exceeds 10,000, gels are likely to be formed, and the viscosity and melt viscosity become high, resulting in a decrease in moldability. It is preferably from 500 to 5,000, more preferably from 700 to 2,500, and still more preferably from 900 to 2,000.

[0056] As the molecular weight distribution (Mw / Mn), it is in the range of 50.0 or less. If Mw / Mn exceeds 50.0, problems such as deterioration of the processing characteristics of the copolymer and generation of gels will occur. It is preferably 30.0 or less, more preferably 20.0 or less, still more preferably in the range of 1.1 to 15.0, and most preferably in the range of 5.0 to 12.0.

[0057] The vinyl equivalent of the soluble polyfunctional vinyl aromatic copolymer is preferably from 150 to 1,000 g / eq., more preferably from 200 to 800 g / eq., and still more preferably from 300 to 500 g / eq.

[0058] The soluble polyfunctional vinyl aromatic copolymer of the present invention is soluble in a solvent selected from toluene, xylene, tetrahydrofuran, dichloroethane, or chloroform. Here, being soluble in a solvent means dissolving 5 g or more, preferably 10 g or more, in 100 g of the solvent at 25°C. In order to be a polyfunctional copolymer soluble in a solvent, it is necessary to leave a part of the vinyl groups of divinylbenzene uncrosslinked and have an appropriate degree of crosslinking.

[0059] The soluble polyfunctional vinyl aromatic copolymer of the present invention is characterized in that it does not contain a halogen-based element other than fluorine as an impurity in an amount of 10 ppm or more in the compound after production. Depending on the type of catalyst used in the polymerization process or the like, halogen elements may be mixed into the copolymer. If the copolymer contains a halogen-based element, it will not only cause deterioration of dielectric properties but also cause migration, etc., having an adverse effect on electrical reliability.

[0060] When a soluble polyfunctional vinyl aromatic copolymer is made into a resin composition containing a radical polymerization initiator, the minimum melt viscosity (η1) is preferably 100 Pa·s or less, more preferably 70 or less, and still more preferably 40 or less. The ratio (η2 / η1) of the melt viscosity (η2) at a temperature of η1 + 5°C is less than 5.0, preferably less than 4.5. When η1 is greater than 100 Pa·s, the resin cannot be softened sufficiently, so the resin fluidity deteriorates, and the filling property of the circuit deteriorates when used as a multilayer substrate or a BUF, etc. The resin fluidity can be evaluated by the method described in "JIS C 6521" and is preferably 15% or more, more preferably 20% or more, from the viewpoint of circuit filling property. When the ratio (η2 / η1) of η2 to η1 is 5.0 or more, the curing rate of the resin is too fast, so the softened resin cures before filling the circuit, and in this case, the circuit filling property is also poor.

[0061] The soluble polyfunctional vinyl aromatic copolymer of the present invention is preferably produced by using a divinyl aromatic compound (a) and a monovinyl aromatic compound (b) at a ratio of (a) of 18 mol% or more and less than 35% based on the total of (a) and (b), adding a Lewis acid catalyst (d) and a Lewis base compound (e) that do not contain halogens other than fluorine, and polymerizing them at a temperature of 85 to 120°C.

[0062] When only less than 18 mol% of the divinyl aromatic compound (a) is used, the proportion of the unsaturated bond functional groups (a1) and (ta1) structures in the copolymer becomes low, the crosslinking density decreases, and as a result, the CTE deteriorates. On the other hand, when (a) is contained in an amount of 35 mol% or more, the proportion of the (a1) and (ta1) structures in the copolymer is excessive, and unsaturated bonds remain after the copolymer is cured, and the physical properties deteriorate due to the thermal history in the processing step. Based on the total of (a) and (b), it is preferable to use the divinyl aromatic compound (a) at a ratio of 25 mol% or more and less than 33%.

[0063] As the divinyl aromatic compound (a), for example, diisopropenylbenzene, divinylbenzene, diisopropenylnaphthalene, divinylnaphthalene, diisopropenylbiphenyl, divinylbiphenyl are preferably used, but are not limited to these. These compounds may contain isomers such as meta-forms and para-forms, and may be a mixture of these isomers.

[0064] Examples of the monovinyl aromatic compound (b) include vinyl aromatic compounds such as styrene, vinylnaphthalene, vinylbiphenyl, and α-methylstyrene; nucleus-alkyl substituted vinyl aromatic compounds such as methylstyrene, dimethylstyrene, and ethylvinylbenzene; and cyclic vinyl aromatic compounds such as indene, acenaphthene, benzothiophene, and coumarone. However, the examples are not limited to these. These compounds also include various isomers and may be an isomer mixture.

[0065] As the comonomer component of the raw material, in addition to the divinyl aromatic compound (a) and the monovinyl aromatic compound (b), other monomers such as trivinyl aromatic compounds, trivinyl aliphatic compounds, divinyl aliphatic compounds, and monovinyl aliphatic compounds can be used within the range that does not impair the effects of the present invention. When they are blended, for example, the blending amount can be less than 30 mol% based on the total amount of all monomer components.

[0066] The copolymer of the present invention can be obtained by polymerization at a temperature of 85 to 120°C. When polymerizing at a temperature exceeding 120°C, the selectivity of the reaction significantly deteriorates. Taking (a1) and (ta1) in the copolymer as the reaction points, the reaction frequency between the copolymers increases, resulting in an increase in the molecular weight distribution and gelation. When polymerizing at a temperature below 85°C, the selectivity of the reaction is improved, and the reaction between the above-mentioned copolymers is suppressed. On the other hand, the chain transfer reaction of the monomers (a) and (b) generated during the growth reaction is also sufficiently suppressed. Therefore, the number of copolymer chains easily increases, and it is difficult to suppress the number-average molecular weight to a low level. In the polymerization at a temperature below 85°C, in order to suppress the molecular weight of the copolymer to a low level, the proportion of (a1) and (ta1) as the reaction points in the copolymer can be reduced. However, as described above, this method will cause a decrease in the crosslinking density, resulting in deterioration of the CTE.

[0067] The Lewis acid catalyst (d) used in the polymerization of the copolymer of the present invention can be used without particular limitation as long as it is a compound composed of a metal ion (acid) and a ligand (base) and does not contain a halogen compound other than a fluorine atom in the molecule and can accept an electron pair. Among them, from the viewpoint of the thermal decomposition resistance of the obtained soluble polyfunctional vinyl aromatic copolymer, metal fluorides or their complexes are preferred, and metal fluorides or their complexes of divalent to hexavalent metals such as B, Al, Ga, In, Si, Ge, Sn, Pb, Sb, Bi, Ti, W, Zn, Fe, and V are particularly preferred. These catalysts can be used alone or in combination of two or more. If a catalyst containing a halogen other than a fluorine atom is used, the halogen ions liberated from the catalyst will be added to the copolymer, which causes deterioration of physical properties. From the viewpoints of controlling the molecular weight and molecular weight distribution of the obtained soluble polyfunctional vinyl aromatic copolymer and the polymerization activity, boron trifluoride ether complex is most preferably used. Among them, as the ether of the ether complex, there are diethyl ether, dimethyl ether, etc.

[0068] Relative to a total of 100 moles of all monomer components, the Lewis acid catalyst (d) can be used in the range of 0.001 to 50 moles, more preferably 0.01 to 20 moles. Most preferably, it is 0.05 to 10 moles. If it exceeds 50 moles, the polymerization rate is too high, so it is difficult to control the molecular weight distribution. In addition, if it is less than 0.001 mole, the polymerization rate is too small, resulting in an increase in cost and being unsuitable for industrial implementation.

[0069] In the method for producing the soluble polyfunctional vinyl aromatic copolymer of the present invention, one or more Lewis base compounds (e) are used as a cocatalyst. From the viewpoint of the reaction temperature, the boiling point of the Lewis base compound (e) is preferably above the reaction temperature. Specific examples of the Lewis base compound (e) include the following compounds. 1) Ester compounds such as propyl acetate, butyl acetate, phenyl acetate, and methyl propionate, 2) Thioester compounds such as methyl mercaptopropionate and ethyl mercaptopropionate, 3) Ketone compounds such as methyl isobutyl ketone and benzophenone, 4) Amine compounds such as methylamine, ethylamine, propylamine, butylamine, cyclohexylamine, methyl ethylamine, dimethylamine, diethylamine, dipropylamine, and dibutylamine, 5) Ether compounds such as diethyl ether and tetrahydrofuran, 6) Thioether compounds such as diethyl sulfide and diphenyl sulfide, and 7) Phosphine compounds such as tripropylphosphine, tributylphosphine, trihexylphosphine, tricyclohexylphosphine, trioctylphosphine, vinylphosphine, propenylphosphine, cyclohexenylphosphine, dienylphosphine, and trienylphosphine. Among them, from the viewpoint of synergistic action with the Lewis acid catalyst (d) and being able to easily control the polymerization rate and the molecular weight distribution of the polymer, one or more compounds selected from ester compounds, ketone compounds, ketone compounds, and ether compounds are preferred, and ester compounds and ketone compounds are more preferably used. These Lewis base compounds (e) can be used singly or in combination of two or more.

[0070] During the polymerization reaction, the Lewis base compound (e) coordinates with the Lewis acid catalyst (d) serving as a counter anion to control the interaction between the carbocation as the active species and the counter anion, thereby regulating the relative reaction frequency between the monomers (a) and (b) that can also function as a chain transfer agent. Generally, by adding the Lewis base compound (e), the interaction between the carbocation as the active species and the counter anion is enhanced. Therefore, the insertion reaction of the monomers (a) and (b) is inhibited from occurring excessively, and the chain transfer reaction after the insertion reaction of the monomers (a) and (b) easily occurs, and the molecular weight is easily controlled.

[0071] Relative to a total of 100 moles of all monomer components, the Lewis base compound (e) is preferably 1.0 to 1000 moles, more preferably 5.0 to 500 moles, and particularly preferably 10 to 200 moles. If it is below the lower limit of the above range, the polymerization rate is too fast and it is difficult to control the molecular weight. On the other hand, if it exceeds the upper limit of the above range, since the concentration of the monomer becomes low, the amount of the obtained copolymer decreases, and thus the production efficiency is poor.

[0072] As the mixing ratio of the Lewis acid catalyst (d) and the Lewis base compound (e), in terms of the ratio of the Lewis acid catalyst / Lewis base compound (d / e), it is preferably 1 to 30×10 -3 (mol / mol), more preferably 3 to 20×10 -3 (mol / mol).

[0073] Next, the curable resin composition of the present invention will be described.

[0074] The curable resin composition of the present invention contains the soluble polyfunctional vinyl aromatic copolymer of the present invention and a radical polymerization initiator (radical polymerization catalyst) as essential components.

[0075] As the free radical polymerization initiator, known substances can be used without particular limitation, and peroxide-based, azo compound-based substances, etc. can be used. For example, benzoyl peroxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, di-tert-butyl peroxide, tert-butyl cumyl peroxide, α,α'-bis(tert-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, dicumyl peroxide, di-tert-butyl isophthalate peroxide, tert-butyl benzoate peroxide, 2,2-bis(tert-butylperoxy)butane, 2,2-bis(tert-butylperoxy)octane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, bis(trimethylsilyl) peroxide, trimethylsilyl triphenylsilyl peroxide and other peroxides, 2,2'-azobis(isobutyronitrile), 4,4'-azobis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl-4-cyanovaleric acid), 2,2'-azobis(2,4,4-trimethylpentane), dimethyl-2,2'-azobis(2-methylpropionate), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(N-butyl-2-methylpropionamide), 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropamidine] tetrahydrate and other azo compounds, and 2,3-dimethyl-2,3-diphenylbutane, etc. can be used alone or in combination of two or more kinds.

[0076] Regarding 100 parts by weight of the soluble polyfunctional vinyl aromatic copolymer, as long as the compounding amount of the free radical polymerization initiator is in the range of 0.01 to 10 parts by weight, the reaction can proceed well without hindering the curing reaction.

[0077] The curable resin composition of the present invention may contain a thermosetting compound and / or a thermoplastic resin other than the soluble polyfunctional vinyl aromatic copolymer as needed.

[0078] A thermosetting compound refers to a resin having reactive substituents or a low-molecular crosslinking agent. As the reactive substituents, from the viewpoint of dielectric properties, compounds having unsaturated carbon-carbon double bonds are particularly preferred. As the thermosetting resin, for example, vinyl ester resins, polyvinylbenzyl resins, unsaturated polyester resins, curable vinyl resins, diisopropenylbenzene resins, allyl ether resins, maleimide resins, epoxy resins, polycyanate resins, phenolic resins, benzocyclobutene resins, and one or more vinyl compound classes having one or more polymerizable unsaturated hydrocarbon groups in the molecule can be cited. In addition, as representative examples of the thermosetting crosslinking agent, 1,4-divinylbenzene, 1,3-divinylbenzene, trivinylbenzene, divinylnaphthalene, 1,2-bis(4-vinylphenyl)ethane, triallyl cyanurate, triallyl isocyanurate, etc. can be cited.

[0079] As the thermoplastic resin, for example, polystyrene, polyphenylene ether resin, polyetherimide resin, polyethersulfone resin, PPS resin, polycyclopentadiene resin, polycycloolefin resin, etc. can be cited. Known thermoplastic elastomers, for example, styrene-ethylene-propylene copolymer, styrene-ethylene-butene copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, hydrogenated styrene-butadiene copolymer, hydrogenated styrene-isoprene copolymer, etc., or rubbers, for example, polybutadiene, polyisoprene.

[0080] The curable resin composition of the present invention may further contain a crosslinking aid. The crosslinking aid refers to a compound in a liquid state or a solid state with a low melt viscosity and containing two or more unsaturated bonds in the molecule, and is a compound added for the purpose of imparting heat resistance by increasing the crosslinking density of the curable resin composition or adjusting the melt viscosity. As the crosslinking aid, for example, divinylbenzene, trivinylbenzene, 2-vinylnorbornene, divinylphenyl ethane, divinylnaphthalene, 1,3-diisopropenylbenzene, triallyl cyanurate, polyfunctional methacrylate, etc. can be cited, but are not limited to the examples listed herein. The divinyl aromatic compound necessary as a raw material of the copolymer of the present invention can also be used as an additive separately.

[0081] The curable resin composition of the present invention may contain an inorganic filler. As specific examples of the inorganic filler, commercially available fused silica, crystalline silica, alumina, silicon nitride, aluminum nitride, etc. can be used. In addition, a substance that reduces the hydroxyl groups on the surface of the filler by controlling the calcination conditions, etc. in the manufacturing process, and a substance that reduces the hydroxyl groups and improves the adhesion to the resin by bonding the hydroxyl groups on the surface to a silane coupling agent, etc. can also be preferably used, but are not limited to the examples listed here. By adding an inorganic filler to the composition, the thermal expansion of the composition can be reduced, and when used for circuit board applications, by reducing the difference in linear expansion between the resin and the metal wiring layer, adverse phenomena such as circuit breakage during use can be prevented.

[0082] By incorporating a high-dielectric powder such as barium titanate or an inorganic magnetic material such as ferrite as another type of inorganic filler, a resin composition suitable as a material for electronic components, particularly for high-frequency electronic component materials, can be obtained.

[0083] The curable resin composition of the present invention may also be formulated with a flame retardant. As the flame retardant, known flame retardants such as bromine-based flame retardants, phosphate-based flame retardants, phosphazene-based flame retardants, phosphite-based flame retardants, and reactive flame retardants having reactive substituents such as unsaturated groups or epoxy groups in the molecule can be widely used.

[0084] In the curable resin composition of the present invention, other additives may also be incorporated as needed. For example, a radical polymerization initiator (radical polymerization catalyst), defoamers such as silicone-based defoamers and acrylate-based defoamers, heat stabilizers, antistatic agents, ultraviolet absorbers, dyes or pigments, lubricants, wetting dispersants, etc.

[0085] The curable resin composition of the present invention can be used as a resin varnish, cured product, film, composite material, laminate, and metal plate with resin, etc. These uses are mainly for circuit board materials. As specific examples of the uses, printed wiring boards, printed circuit boards, flexible printed wiring boards, build-up wiring boards, etc. can be cited.

[0086] When preparing the resin varnish, the curable composition of the present invention is dissolved in an organic solvent. As the organic solvent, as long as it can dissolve the curable resin composition and does not hinder the curing reaction, there is no particular limitation, and known organic solvents can be used. For example, aromatic hydrocarbon solvents such as toluene and xylene, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ethers such as tetrahydrofuran and dioxolane, esters such as ethyl acetate, propyl acetate, and butyl acetate, polar solvents such as dimethylacetamide, etc. These solvents can be used alone or in combination of two or more.

[0087] When producing a resin varnish, the amount of the organic solvent used is, for example, in the range of 10 to 1000 parts by weight relative to 100 parts by weight of the curable composition of the present invention.

[0088] The cured product obtained by curing the curable composition containing the soluble polyfunctional vinyl aromatic copolymer of the present invention can be used as a molded article, a laminate, a casting, an adhesive, a coating film, or a film. For example, the cured product of a semiconductor encapsulation material is a casting or a molded article. As a method for obtaining the cured product for the above uses, the curable composition can be cast or molded using a transfer molding machine, an injection molding machine, etc., and further cured by heating at, for example, 70 to 230 °C for 0.5 to 10 hours to obtain the cured product.

[0089] The curable resin composition of the present invention can be made into a curable composite material together with a substrate. The curable composite material can be obtained by uniformly dissolving or dispersing the curable composition in an organic solvent to obtain a resin varnish, impregnating the substrate with the resin varnish by impregnation or coating, and then heating and drying. The curable composite material is also called a prepreg.

[0090] The substrate mainly refers to materials such as fibers or paper that can be impregnated with resin and can improve mechanical strength and dimensional stability after curing. As the substrate, well-known materials can be widely used without limitation. For example, various glass cloths such as untwisted gauze, gauze, chopped strand mat, and surface mat, asbestos cloth, metal fiber cloth, other synthetic or natural inorganic fiber cloths, woven or non-woven fabrics obtained from liquid crystal fibers such as wholly aromatic polyamide fibers, wholly aromatic polyester fibers, and polybenzazole fibers, woven or non-woven fabrics obtained from synthetic fibers such as polyvinyl alcohol fibers, polyester fibers, and acrylic fibers, natural fiber cloths such as cotton cloth, linen cloth, and felt, carbon fiber cloth, kraft paper, cotton paper, paper-glass mixed fiber paper, etc., can be used alone or in combination of two or more. As the material of the glass cloth, there are E glass, NE glass, L glass, Q glass, etc. In particular, a glass cloth with reduced hydroxyl groups on the glass surface and treated to improve the adhesion with the resin on the glass fiber surface is suitable for use as a circuit board for high-speed communication purposes.

[0091] In the curable composite material, the amount of the substrate used can be appropriately selected according to the purpose, for example, in the range of 5 to 90 wt%. If the substrate is less than 5 wt%, the dimensional stability or strength of the composite material after curing is insufficient. On the other hand, if the substrate exceeds 90 wt%, the dielectric properties of the composite material are poor, which is not preferable. In the curable composite material, a coupling agent, such as a silane coupling agent, a titanate coupling agent, an aluminum-based coupling agent, a zirconium aluminate coupling agent, etc., can be used as needed for the purpose of improving the adhesion at the interface between the resin and the substrate.

[0092] The curable composite material can be cured by methods such as heating to obtain a cured composite material. Its manufacturing method is not particularly limited. For example, multiple sheets of curable composite materials can be overlapped, bonded between layers under heating and pressure, and thermally cured simultaneously to obtain a cured composite material with a desired thickness. In addition, a cured composite material with a new layer structure can also be obtained by combining a cured composite material that has been adhesively cured once with a curable composite material. Laminating and curing are usually carried out simultaneously by hot pressing or the like, but the two can also be carried out separately. That is, the uncured or semi-cured composite material obtained by pre-laminating and forming can be cured by heat treatment or other methods.

[0093] Forming and curing can be carried out, for example, in an inert gas atmosphere, at a temperature of 80 to 300 °C, a pressure of 0.1 to 1000 kg / cm 2 , and within a time range of 1 minute to 10 hours.

[0094] The laminate of the present invention is composed of a cured composite material layer and a metal foil layer, and an adhesive can be used as needed. Examples of the metal foil include copper foil, aluminum foil, etc., and its thickness is, for example, in the range of 1 to 200 μm.

[0095] The curable composition of the present invention can also be formed into a film with a thickness of, for example, 1 to 200 μm.

[0096] Examples

[0097] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. It should be noted that all parts in each example represent parts by weight, and the physical properties are measured by the methods shown below.

[0098] 1) Molecular weight and molecular weight distribution of the copolymer (soluble polyfunctional aromatic copolymer) The molecular weight and molecular weight distribution are measured using GPC. Specifically, an apparatus having columns (TSKgel G4000HXL, TSKgel G3000HXL, TSKgel G2000HXL, manufactured by TOSOH Corporation) connected in series to the main body (HLC-8320GPC, manufactured by TOSOH Corporation) is used, and the column temperature is set to 40 °C. In addition, tetrahydrofuran (THF) is used as the eluent, the flow rate is 1 mL / minute, and a differential refractive index detector is used. As the measurement sample, 50 μL of a solution obtained by dissolving 0.05 g of the sample in 10 mL of THF and filtering it with a microfilter is used. Conversion is performed using a calibration curve obtained from standard monodisperse polystyrenes (A-500, A-1000, A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40, F-80, F-128, manufactured by TOSOH Corporation).

[0099] 2) Structure of the copolymer

[0100] Determined by using a JNM-ECZ400R / S1 nuclear magnetic resonance spectrometer manufactured by JEOL RESONANCE, Ltd. through 13 C-NMR and 1 H-NMR analysis. Chloroform-d1 was used as the solvent, and the peak observed at 7.25 ppm in chloroform was used as the internal standard.

[0101] 3) Analysis of unsaturated functional substituents

[0102] The unsaturated functional substituents in the copolymer were quantified by combining multiple measurements. The measurement methods used are described below. The consumption of each monomer during polymerization was determined by using a GC-2010 gas chromatograph manufactured by Shimadzu Corporation, with 4-acetylbiphenyl as the internal standard, and the ratio of each monomer component in the copolymer was calculated from the amount of monomer consumed during polymerization. In addition, the number-average molecular weight was analyzed using the results of the above GPC analysis. The content ratios of the structural units of the copolymer such as vinyl and 1,2-substituted ethylene were determined by using a JNM-ECZ400R / S1 nuclear magnetic resonance spectrometer manufactured by JEOL RESONANCE, Ltd. through 13 C-NMR and 1 H-NMR analysis. Chloroform-d1 was used as the solvent, and the peak observed at 7.25 ppm in chloroform was used as the internal standard.

[0103] 4) Determination of vinyl equivalent

[0104] The vinyl equivalent of the copolymer was determined by the iodine value determination using the Wijs method. First, 0.3 g of the solid component of the sample was weighed into an Erlenmeyer flask and diluted with 20 ml of toluene. 25 ml of a commercially available 0.1 mol / L Wijs reagent (iodine monochloride - acetic acid solution) was pipetted into this solution, stirred, and allowed to stand in the dark for 30 minutes. 20 mass% aqueous potassium iodide solution and 100 ml of pure water were added to this solution, stirred vigorously, transferred to a beaker, and titrated with 0.1 mol / l aqueous sodium thiosulfate solution using an automatic titrator (manufactured by Hiranuma Sangyo Co., Ltd., combined electrode PT-301), and the iodine value was calculated by the following mathematical formula 3.

[0105] Iodine value (g / 100) = (B - A) × F × 1.269 / sample amount (g)

[0106] ···(Mathematical formula 3)

[0107] Where,

[0108] A: Titration volume (cc) of 0.1 mol / L aqueous sodium thiosulfate solution required for neutralization,

[0109] B: The titration volume (cc) of 0.1 mol / L sodium thiosulfate aqueous solution required for the blank determination

[0110] F: The titration degree of 0.1 mol / L sodium thiosulfate aqueous solution

[0111] The vinyl equivalent is calculated from the iodine value thus obtained by the following mathematical formula 4

[0112] Vinyl equivalent (g / eq.) = 100 × 253.81 / iodine value

[0113] ···(Mathematical formula 4)

[0114] 5) Determination of halogen element content

[0115] The content of each element of chlorine, bromine, and iodine is determined by combustion ion chromatography. The device used is the Dionex Aquion ion chromatograph manufactured by Thermo Scientific. The detection limit of this method is 5 ppm

[0116] 6) Determination of the coefficient of linear expansion (CTE) of the cured product

[0117] The copolymer composition varnish is uniformly coated on a polyethylene terephthalate film, and the coated film is dried by heating in an oven at 125 °C for 10 minutes. The dried product on the film is peeled off, pulverized to make a powder, and the powder is put into a fluororesin mold frame with a thickness of 1 mm. The temperature is raised to 210 °C under reduced pressure, and further heat treatment is carried out at 210 °C for 120 minutes under a pressure of 2.0 MPa to cure the copolymer composition. After the molded product is cooled to room temperature, it is taken out, and the obtained test piece is installed on a TMA (thermal mechanical analysis device), and a scanning measurement is carried out from 30 °C to 320 °C at a heating rate of 5 °C / minute in a nitrogen gas stream in the compression mode. The coefficient of linear expansion (CTE) is obtained from the slope of the temperature-elongation curve from 130 °C to 150 °C

[0118] The glass transition temperature is obtained as follows: The above-mentioned test piece is installed on a DMA (dynamic viscoelasticity device) measurement device, and a three-point bending measurement mode is adopted. The measurement is carried out from 30 °C to 320 °C at a heating rate of 2 °C / minute in a nitrogen gas stream, and Tg is obtained from the peak of the tanδ curve

[0119] 7) Minimum melt viscosity (η1) and η2

[0120] A copolymer composition varnish was uniformly coated on a polyethylene terephthalate film, and the coated film was dried by heating in an oven at 125 °C for 10 minutes. The dried material on the film was peeled off and pulverized, and the powdered sample was mounted on a rheometer. Subsequently, the temperature-viscosity curve was measured by the parallel plate method. From the obtained graph, the viscosity at the point where the viscosity decreased the most was determined as the lowest melting viscosity (η1), and the viscosity at the point of the temperature of η1 + 5 °C was determined as η2. The rheometer used was HAAKE RheoStress 600 manufactured by Thermo Scientific.

[0121] 8) Resin fluidity test

[0122] The measurement was carried out in accordance with JISC 6521. It was carried out under the pressing conditions of 210 °C and 1.38 MPa.

[0123] 9) Evaluation of bonding reliability

[0124] The change in the bondability before and after the HAST (Highly Accelerated Temperature and Humidity Stress Test) was measured and evaluated. Specifically, it was carried out as follows.

[0125] (i) Preparation of evaluation substrate

[0126] <Evaluation of bondability>

[0127] The evaluation of the bondability was carried out by measuring the copper foil peel strength according to the following steps.

[0128] <Fabrication of evaluation substrate>

[0129] (1) Substrate treatment of copper foil

[0130] The shiny surface of "3EC-III" (electrolytic copper foil, 35 μm) manufactured by Mitsui Mining & Smelting Co., Ltd. was etched by 1 μm using "CZ8101" manufactured by MEC Co., Ltd. to roughen the copper surface, and then an anti-rust treatment (CL8300) was carried out. This copper foil was used as the CZ copper foil. Further, it was heat-treated in an oven at 130 °C for 30 minutes. Thus, an inner layer substrate was obtained.

[0131] (2) Preparation of inner layer substrate

[0132] Both sides of a glass cloth base epoxy resin double-sided copper clad laminate (copper foil thickness 18 μm, substrate thickness 0.4 mm, "R1515A" manufactured by Panasonic Corporation) having an inner layer circuit were etched by 1 μm using "CZ8101" manufactured by MEC Co., Ltd. to roughen the copper surface. Thus, a CZ copper foil with a treated surface was obtained.

[0133] (3) Preparation of resin sheet

[0134] Prepare a polyethylene terephthalate film with a release layer (Nippa Co., Ltd.'s "1-V4", thickness 50 μm) as the support. The resin varnishes described in the examples and comparative examples prepared by the method described later are uniformly coated on the release layer of the support so that the thickness of the dried resin composition layer becomes 25 μm. Thereafter, the resin varnish is dried at 90 °C to 130 °C (average 110 °C) for 5 minutes to remove the solvent, and a resin sheet including the support and the resin composition layer is obtained.

[0135] (4) Lamination of resin composition layer

[0136] The resin sheet with the support prepared as described above is laminated on both sides of the inner layer substrate such that the resin composition layer is in contact with the above-mentioned inner layer substrate. The lamination is carried out by using a batch-type vacuum lamination device to reduce the air pressure to 15 hPa or less by decompression for 60 seconds, and then crimping at 125 °C under a pressure of 0.70 MPa for 30 seconds. Next, hot pressing is carried out at 100 °C under a pressure of 0.5 MPa for 60 seconds. Thereafter, the support is peeled off to expose the resin composition layer.

[0137] (5) Lamination of copper foil and curing of resin composition layer

[0138] On the exposed resin composition layer, the treated surface of the CZ copper foil is laminated under the same conditions as above. Then, the resin composition layer is cured under the curing conditions of 200 °C for 90 minutes to form a cured product (insulating layer). Thus, an evaluation substrate with CZ copper foil laminated on both sides is obtained.

[0139] <Measurement of copper foil peel strength before HAST>

[0140] The fabricated evaluation substrate is cut into small pieces of 150 mm × 30 mm. Using a cutter, a cut is made in the copper foil part of the small piece with a width of 10 mm and a length of 100 mm. One end is peeled off and clamped with the fixture of the tensile testing machine described later, and the load [N / mm] when peeling 35 mm in the vertical direction at a speed of 50 mm / minute is measured at room temperature (normal temperature). The value of the load obtained from the measurement result is used as the "copper foil peel strength before HAST". The measurement is carried out using a tensile testing machine (Universal Testing Machine "Autograph EZ-S-50N" manufactured by Shimadzu Corporation). The measurement is carried out in accordance with Japanese Industrial Standard JIS C6481. Substrates with a copper foil peel strength before HAST of 0.40 N / mm or more are marked as "○", substrates with a result less than 0.4 N / mm are marked as "×", and the results are shown in Table 1.

[0141] <Measurement of copper foil peel strength after HAST>

[0142] For the fabricated evaluation substrate, an accelerated environmental test was conducted for 100 hours under high-temperature and high-humidity conditions of 130 °C and 85% RH using a highly accelerated life test device (“PC-242HS-A” manufactured by Hirayama Seisakusho). After that, a cut was made in the evaluation substrate after HAST in the same manner as above. Similar to the above measurement, one end of the cut was peeled off and clamped with the fixture of the above tensile testing machine, and the load [N / mm] was measured at room temperature (normal temperature) when peeling 35 mm in the vertical direction at a speed of 50 mm / min. The load value obtained from the result of this measurement was used as the “copper foil peel strength after HAST”. The measurement was carried out in accordance with Japanese Industrial Standard JISC6481. Substrates with a difference in copper foil peel strength after HAST and before HAST of less than 0.1 N / mm were marked as “○”, and substrates with a result of 0.1 N / mm or more were marked as “×”. The results are shown in Table 1.

[0143] The content of the compounds described in the following examples is as follows.

[0144] Copolymers A, B, C, and D: As described in the examples below

[0145] Thermosetting compound E-1: DVB-630 (a mixture of 1,4-divinylbenzene, 1,3-divinylbenzene, 1,4-ethylvinylbenzene, and 1,3-ethylvinylbenzene, manufactured by NIPPON STEEL Chemical&Material Co., Ltd.)

[0146] Thermosetting compound E-2: OPE-2St (a polyphenylene ether resin modified with vinylbenzyl ether at the end, manufactured by Mitsubishi Gas Chemical Co., Ltd.)

[0147] Thermoplastic resin F: TUFTEC H1043 (a hydrogenated styrenic thermoplastic elastomer, manufactured by Asahi Kasei Corporation)

[0148] Polymerization initiator G: PERBUTYL P (1,3-bis(tert-butylperoxyisopropyl)benzene, manufactured by NOF Corporation)

[0149] Stabilizer H: ADK STAB AO-60 (tetrakis[methylene-3-(3’,5’-di-tert-butyl-4-hydroxyphenyl)propionate]methane, manufactured by ADEKA Corporation)

[0150] Inorganic filler I: SE2050 SPE, (amorphous silica with an average particle size of 0.5 μm and treated with phenylsilane coupling agent, manufactured by Admatechs Co., Ltd.)

[0151] Example 1

[0152] Charge into a 1.0 L reactor: 0.57 mol (81.4 mL) of divinylbenzene (the following structural formula, a mixture of 1,4-divinylbenzene and 1,3-divinylbenzene, the same applies to the following examples),

[0153]

[0154] 0.34 mol (47.8 mL) of ethylvinylbenzene (the following structural formula, a mixture of 1-ethyl-4-vinylbenzene and 1-ethyl-3-vinylbenzene, the same applies to the following examples),

[0155]

[0156] 1.95 mol (224.3 mL) of styrene (the following structural formula),

[0157]

[0158] and 2.99 mol (344.4 mL) of n-propyl acetate, and heat. Add 23 mmol of boron trifluoride diethyl ether complex at the state when the temperature rises to 100 °C, and react for 3.5 hours.

[0159] After adding 166 ml of 7% aqueous sodium bicarbonate solution to the polymerization solution to stop the reaction, extract and wash the oil layer with pure water 3 times. Pour this reaction into a large amount of methanol to produce a white precipitate, recover the white precipitate and weigh the obtained polymer, and confirm that 165.3 g of copolymer A-1 is obtained.

[0160] Analyze the obtained copolymer A-1 by GPC. The results show that Mn is 1200, Mw is 10500, and Mw / Mn is 8.75. Measure the vinyl equivalent of A-1, and the result is 410 (g / eq.), and calculate the number of unsaturated bond functional groups to be 2.93 by (mathematical formula 1).

[0161] According to the results of GC analysis, the structures contained in the copolymer are as described below.

[0162] Structural unit from divinylbenzene (a): 31.0 mol% (34.9 wt%)

[0163] Structural unit from ethylvinylbenzene (b-1): 12.9 mol% (14.7 wt%)

[0164] Structural unit from styrene (b-2): 56.1 mol% (50.4 wt%)

[0165] The 1 1H-NMR spectrum of copolymer A-1 is shown in Figure 1 . 1The results of the 1H-NMR analysis showed that resonance lines attributed to the vinyl groups contained in (a1) and (ta1) were observed at 4.83 - 5.33 ppm and 5.37 - 5.82 ppm, and the integration value of one hydrogen in this structure was normalized to 1. It should be noted that the integration value in the 1H-NMR analysis in Example 1 was based on this normalized value. 1 The integration value of the 1H-NMR analysis was based on this normalized value.

[0166] Resonance lines attributed to the aromatic rings in the structural units from (a), (b-1), and (b-2) were observed at 5.84 - 7.57, and the total integration value was 20.31.

[0167] In addition, resonance lines attributed to the 1,2-disubstituted ethylenes in (ta1), (ta2), and (tb1) were observed at 5.95 - 6.23. Since the resonance lines overlapped with those of the aromatic rings from (a), (b-1), and (b-2), the baseline described in Figure 1 was used, and only the part observed as a shoulder from the resonance lines of the above aromatic rings was taken as the integration value. As a result, the integration value was found to be 0.12.

[0168] Based on the ratio of the above integration values, the proportion of the unsaturated bond functional groups from the vinyl groups contained in (a1) and (ta1) relative to the number of unsaturated bond functional groups was calculated to be 89.3 mol%, and the proportion of the unsaturated bond functional groups from the 1,2-disubstituted ethylenes contained in (ta1), (ta2), and (tb1) was 10.7 mol%. The functional group equivalent of the 1,2-disubstituted ethylene was calculated to be 3827 (g / eq.) by (mathematical formula 2).

[0169] Copolymer A-1 was soluble in toluene, xylene, tetrahydrofuran, dichloroethane, or chloroform, and no gel formation was observed.

[0170] The analysis of each element of chlorine, bromine, and iodine showed that the content rates were all lower than the detection limit (5 ppm).

[0171] According to the compounding composition (parts by weight) described in Table 1, copolymer A-1, toluene as a solvent, polymerization initiator G, and stabilizer H were added and mixed using an oscillator to obtain a copolymer composition varnish of copolymer A-1.

[0172] Using the obtained copolymer composition varnish, the physical properties were measured according to the procedures described in the above respective test methods. The obtained results are summarized in Table 1.

[0173] Example 2

[0174] In a 1.0 L reactor, 0.61 mol (86.9 mL) of divinylbenzene, 0.36 mol (51.0 mL) of ethyl vinylbenzene, 2.08 mol (239.3 mL) of styrene, and 3.18 mol (419.0 mL) of n-butyl acetate were charged and heated. When the temperature rose to 110 °C, 25 mmol of boron trifluoride diethyl ether complex was added and the reaction was carried out for 2.5 hours.

[0175] After the reaction was stopped by adding 177 mL of 7% aqueous sodium bicarbonate solution to the polymerization solution, the oil layer was extracted and washed three times with pure water. The reaction solution was poured into a large amount of methanol to form a white precipitate. The white precipitate was recovered and the polymer obtained was weighed, and 258.5 g of copolymer A-2 was confirmed to be obtained.

[0176] The obtained copolymer A-2 was analyzed by GPC. As a result, Mn was 930, Mw was 9500, and Mw / Mn was 10.2. The vinyl equivalent of copolymer A-2 was measured, and the result was 380 (g / eq.). The number of unsaturated bond functional groups was calculated to be 2.45 by (Mathematical formula 1).

[0177] Based on the results of GC analysis, the respective structures contained in the copolymer are as described below.

[0178] Structural unit from divinylbenzene (a): 28.8 mol% (32.6 wt%)

[0179] Structural unit from ethyl vinylbenzene (b-1): 13.1 mol% (15.0 wt%)

[0180] Structural unit from styrene (b-2): 58.1 mol% (52.4 wt%)

[0181] In addition, for 1 1H-NMR analysis, the same operation as that for copolymer A-1 was carried out for analysis. Resonance lines obtained were also observed in the same range as that for copolymer A-1.

[0182] Resonance lines attributed to the aromatic rings in the structural units from the above (a), (b-1), and (b-2) were observed at the same positions as those for copolymer A-1, and the total integral value was 24.58.

[0183] In addition, resonance lines attributed to 1,2-substituted ethylenes of (ta1), (ta2), and (tb1) were also observed at the same positions as those for copolymer A-1. Analysis was carried out in the same manner as in Example 1, and as a result, the integral value was determined to be 0.17.

[0184] Based on the ratio of the above integral values, the proportion of the unsaturated bond functional groups derived from the vinyl groups contained in (a1) and (ta1) relative to the number of unsaturated bond functional groups is 85.5 mol%, and the proportion of the unsaturated bond functional groups derived from the 1,2-substituted ethylene groups contained in (ta1), (ta2), and (tb1) is 14.5 mol%. The functional group equivalent of 1,2-substituted ethylene groups is calculated to be 2615 (g / eq.) by (Mathematical formula 2).

[0185] Copolymer A-2 is soluble in toluene, xylene, tetrahydrofuran, dichloroethane, or chloroform, and no gel formation is observed.

[0186] Analyses of each of the elements chlorine, bromine, and iodine show that the content rates are all lower than the detection limit (5 ppm).

[0187] Example 3

[0188] 0.47 mol (67.0 mL) of divinylbenzene, 0.28 mol (39.3 mL) of ethyl vinylbenzene, 1.60 mol (184.4 mL) of styrene, and 3.51 mol (403.3 mL) of n-propyl acetate were charged into a 1.0 L reactor and heated. 48 mmol of boron trifluoride diethyl ether complex was added at the state where the temperature rose to 90 °C, and the reaction was carried out for 1.5 hours.

[0189] After adding 171 ml of 7% aqueous sodium bicarbonate solution to the polymerization solution to stop the reaction, the aqueous phase was removed by liquid separation, 171 ml of 7% aqueous sodium bicarbonate solution was added thereto again, and it was stirred for 30 minutes. Thereafter, the oil layer was extracted and washed with pure water 3 times. The reaction solution was poured into a large amount of methanol to produce a white precipitate, and the white precipitate was recovered and the obtained polymer was weighed, and 359 g of copolymer A-3 was confirmed to be obtained.

[0190] The obtained copolymer A-3 was analyzed by GPC. As a result, Mn was 1400, Mw was 12500, and Mw / Mn was 8.93. The vinyl equivalent of copolymer A-3 was measured, and the result was 398 (g / eq.), and the number of unsaturated bond functional groups was calculated to be 3.52 by (Mathematical formula 1).

[0191] Based on the results of GC analysis, the respective structures contained in the copolymer are as described below.

[0192] Structural unit derived from divinylbenzene (a): 26.2 mol% (29.4 wt%)

[0193] Structural unit derived from ethyl vinylbenzene (b-1): 12.1 mol% (13.8 wt%)

[0194] Structural unit derived from styrene (b-2): 63.1 mol% (56.8 wt%)

[0195] In addition, for 1 1H-NMR analysis, the same operation as for copolymer A was carried out for analysis. Resonance lines obtained were also observed within the same range as copolymer A-1.

[0196] Resonance lines attributed to the aromatic rings in the structural units from the above (a), (b-1), and (b-2) were observed at the same positions as in copolymer A-1, and the total integral value was 22.03.

[0197] In addition, resonance lines attributed to 1,2-substituted ethylenes of (ta1), (ta2), and (tb1) were also observed at the same positions as in copolymer A, and analysis was carried out in the same manner as in Example 1. As a result, the integral value was determined to be 0.09.

[0198] Based on the ratio of the above integral values, the proportion of the unsaturated bond functional groups derived from the vinyl groups contained in (a1) and (ta1) relative to the number of unsaturated bond functional groups was calculated to be 91.7 mol%, and the proportion of the unsaturated bond functional groups derived from the 1,2-substituted ethylenes contained in (ta1), (ta2), and (tb1) was 8.26 mol%. The functional group equivalent of 1,2-substituted ethylene was calculated to be 4820 (g / eq.) by (Mathematical formula 2).

[0199] Copolymer A-3 is soluble in toluene, xylene, tetrahydrofuran, dichloroethane, or chloroform, and no gel formation was observed.

[0200] Analysis of each element of chlorine, bromine, and iodine showed that the content rates were all below the detection limit (5 ppm).

[0201] Comparative Example 1

[0202] 0.60 mol (85.5 ml) of divinylbenzene, 0.36 mol (51.3 ml) of ethyl vinylbenzene, 2.04 mol (234.5 ml) of styrene, and 3.00 mol (345.0 ml) of n-propyl acetate were charged into a 1.0 L reactor. 120 mmol of boron trifluoride ether complex was added at 70 °C, and the reaction was carried out for 4 hours. After stopping the polymerization solution with 7% aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water. This reaction was poured into a large amount of methanol to produce a white precipitate, and the white precipitate was recovered and the obtained polymer was weighed. It was confirmed that 179.3 g of copolymer B-1 was obtained.

[0203] The obtained copolymer B-1 was analyzed by GPC. The results showed that Mn was 3020, Mw was 40500, and Mw / Mn was 13.41. The vinyl equivalent of copolymer B-1 was measured, and the result was 445 (g / eq.). The number of unsaturated bond functional groups was calculated to be 6.79 by (Mathematical formula 1).

[0204] Based on the results of GC analysis, the structures contained in the copolymer were calculated as follows.

[0205] Structural unit from divinylbenzene (a): 29.3 mol% (33.1 wt%)

[0206] Structural unit from ethyl vinylbenzene (b-1): 12.4 mol% (14.2 wt%)

[0207] Structural unit from styrene (b-2): 58.3 mol% (52.7 wt%)

[0208] In addition, for 1 1H-NMR analysis, the same operation as that for copolymer A-1 was carried out for analysis. Resonance lines obtained were also observed within the same range as that for copolymer A-1.

[0209] Resonance lines attributed to the aromatic rings in the structural units from the above (a), (b-1), and (b-2) were observed at the same positions as those for copolymer A-1, and the total integral value was 19.20.

[0210] In addition, resonance lines attributed to 1,2-substituted ethylenes of (ta1), (ta2), and (tb1) were also observed at the same positions as those for copolymer A. Analysis was carried out in the same manner as in Example 1, and as a result, the integral value was determined to be 0.083.

[0211] Based on the ratio of the above integral values, the proportion of unsaturated bond functional groups from the vinyl groups contained in (a1) and (ta1) relative to the number of unsaturated bond functional groups was calculated to be 92.3 mol%, and the proportion of unsaturated bond functional groups from the 1,2-substituted ethylenes contained in (ta1), (ta2), and (tb1) was 7.70 mol%. The functional group equivalent of 1,2-substituted ethylene was calculated to be 5779 (g / eq.) by (Mathematical formula 2).

[0212] Copolymer B-1 was soluble in toluene, xylene, tetrahydrofuran, dichloroethane, or chloroform, and no gel formation was observed.

[0213] Analysis of each element of chlorine, bromine, and iodine showed that the content rates were all lower than the detection limit (5 ppm).

[0214] Comparative Example 2

[0215] In a 1.0 L reactor, 0.30 mol (42.7 ml) of divinylbenzene, 0.18 mol (25.1 ml) of ethylvinylbenzene, 2.52 mol (289.7 ml) of styrene, and 3.00 mol (345.0 ml) of n-propyl acetate were charged. 120 mmol of boron trifluoride ether complex was added at 70 °C, and the reaction was carried out for 4 hours. After stopping the polymerization solution with 7% aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water. This reaction was poured into a large amount of methanol to produce a white precipitate, and the white precipitate was recovered and the obtained polymer was weighed, and 164.2 g of copolymer B-2 was confirmed to be obtained.

[0216] The obtained copolymer B-2 was analyzed by GPC. As a result, Mn was 1500, Mw was 12500, and Mw / Mn was 8.33. The vinyl equivalent of copolymer B-2 was measured, and the result was 831 (g / eq.), and the number of unsaturated bond functional groups was calculated to be 1.81 by (Mathematical formula 1).

[0217] Based on the results of GC analysis, each structure contained in the copolymer was calculated as follows.

[0218] Structural unit from divinylbenzene (a): 11.3 mol% (13.5 wt%)

[0219] Structural unit from ethylvinylbenzene (b-1): 5.81 mol% (7.06 wt%)

[0220] Structural unit from styrene (b-2): 82.9 mol% (79.4 wt%)

[0221] In addition, for 1 1H-NMR analysis, the same operation as that for copolymer A-1 was carried out for analysis. Resonance lines obtained were also observed in the same range as that for copolymer A-1.

[0222] Resonance lines attributed to the aromatic rings in the structural units from the above (a), (b-1), and (b-2) were observed at the same positions as those for copolymer A-1, and the total integral value was 47.8.

[0223] In addition, resonance lines attributed to 1,2-substituted ethylenes of (ta1), (ta2), and (tb1) were also observed at the same positions as those for copolymer A. Analysis was carried out in the same manner as in Example 1, and as a result, the integral value was found to be 0.29.

[0224] Based on the ratio of the above integral values, the proportion of unsaturated bond functional groups derived from vinyl groups contained in (a1) and (ta1) relative to the number of unsaturated bond functional groups is 77.3 mol%, and the proportion of unsaturated bond functional groups derived from 1,2-substituted ethylenes contained in (ta1), (ta2), and (tb1) is 22.7 mol%. The functional group equivalent of 1,2-substituted ethylene is calculated to be 3660 (g / eq.) by (Mathematical formula 2).

[0225] Copolymer B-2 is soluble in toluene, xylene, tetrahydrofuran, dichloroethane, or chloroform, and no gel formation is observed.

[0226] For the analysis of each element of chlorine, bromine, and iodine, the content rates are all lower than the detection limit (5 ppm).

[0227] Comparative Example 3

[0228] In a 1.0 L reactor, 0.45 mol (64.1 ml) of divinylbenzene, 0.26 mol (37.6 ml) of ethyl vinylbenzene, 2.28 mol (262.1 ml) of styrene, and 3.00 mol (345.0 ml) of n-propyl acetate were charged. 120 mmol of boron trifluoride ether complex was added at 70 °C, and the reaction was carried out for 4 hours. After stopping the polymerization solution with 7% aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water. This reaction was poured into a large amount of methanol to produce a white precipitate, and the white precipitate was recovered and the obtained polymer was weighed. It was confirmed that 172.2 g of copolymer B-3 was obtained.

[0229] The copolymer B-3 obtained was analyzed by GPC. As a result, Mn was 2080, Mw was 30800, and Mw / Mn was 14.8. The vinyl equivalent of copolymer B-3 was measured, and the result was 486 (g / eq.). The number of unsaturated bond functional groups was calculated to be 4.28 by (Mathematical formula 1).

[0230] Based on the results of GC analysis, the respective structures contained in the copolymer are as described below.

[0231] Structural unit derived from divinylbenzene (a): 20.9 mol% (24.3 wt%)

[0232] Structural unit derived from ethyl vinylbenzene (b-1): 9.10 mol% (10.7 wt%)

[0233] Structural unit derived from styrene (b-2): 70.0 mol% (65.0 wt%)

[0234] In addition, for 1 1H-NMR analysis, the same operation as for copolymer A-1 was carried out for analysis. The obtained resonance lines were also observed within the same range as for copolymer A-1.

[0235] Resonance lines attributed to the aromatic rings in the structural units from (a), (b-1), and (b-2) above were observed at the same positions as in copolymer A-1, and the total integral value was 28.2.

[0236] In addition, resonance lines attributed to 1,2-substituted ethylenes of (ta1), (ta2), and (tb1) were also observed at the same positions as in copolymer A. Analysis was carried out in the same manner as in Example 1, and as a result, the integral value was found to be 0.10.

[0237] Based on the ratio of the above integral values, the proportion of the unsaturated bond functional groups derived from the vinyl groups contained in (a1) and (ta1) relative to the number of unsaturated bond functional groups was calculated to be 90.5 mol%, and the proportion of the unsaturated bond functional groups derived from the 1,2-substituted ethylenes contained in (ta1), (ta2), and (tb1) was 9.45 mol%. The functional group equivalent of 1,2-substituted ethylene was calculated to be 5141 (g / eq.) by (Mathematical formula 2).

[0238] Copolymer B-3 was soluble in toluene, xylene, tetrahydrofuran, dichloroethane, or chloroform, and no gel formation was observed.

[0239] Analysis of each element of chlorine, bromine, and iodine showed that the content rate was lower than the detection limit (5 ppm).

[0240] Comparative Example 4

[0241] 1.82 moles (259.6 mL) of divinylbenzene, 0.43 moles (60.9 mL) of ethyl vinylbenzene, 0.28 moles (36.9 mL) of n-butyl acetate, and 140 mL of toluene were charged into a 1.0 L reactor. A solution obtained by dissolving 40 millimoles of methanesulfonic acid in 0.12 moles (15.7 mL) of n-butyl acetate was added at 70 °C, and the reaction was carried out for 6 hours. After stopping the polymerization solution with calcium hydroxide, filtration was carried out using activated alumina as a filter aid. The reaction mixture was poured into a large amount of methanol to form a white precipitate, and the white precipitate was recovered and the polymer obtained was weighed. It was confirmed that 221.0 g of copolymer C-1 was obtained.

[0242] The obtained copolymer C-1 was analyzed by GPC. As a result, Mn was 1090, Mw was 12300, and Mw / Mn was 11.28. The vinyl equivalent of copolymer C-1 was measured, and the result was 193 (g / eq.). The number of unsaturated bond functional groups was calculated to be 5.65 by (Mathematical formula 1).

[0243] Based on the results of GC analysis, the respective structures contained in the copolymer are as described below.

[0244] Structural unit derived from divinylbenzene (a): 84.0 mol% (83.8 wt%)

[0245] Structural unit derived from ethyl vinylbenzene (b-1): 16.0 mol% (16.2 wt%)

[0246] In addition, 1 The results of 1H-NMR analysis showed resonance lines attributed to the vinyl groups contained in (a1) and (ta1) were observed at 5.02 - 5.38 ppm and 5.46 - 5.82 ppm. The integral values were determined by analysis in the same manner as in Synthesis Example 1.

[0247] Resonance lines attributed to the aromatic rings in the structural units derived from the above (a) and (b-1) were observed at 5.90 - 7.62, and the total integral value was 8.90.

[0248] In addition, resonance lines attributed to the 1,2-substituted ethylenes of (ta1), (ta2) and (tb1) were observed at 5.90 - 6.23. Since the resonance lines overlapped with the resonance lines of the aromatic rings attributed to (a) and (b-1), the integral values were determined in the same manner as in Example 1. As a result, the integral value was found to be 0.33.

[0249] Based on the ratio of the above integral values, the proportion of the unsaturated bond functional groups of the vinyl groups contained in (a1) and (ta1) relative to the number of unsaturated bond functional groups was calculated to be 75.4 mol%, and the proportion of the unsaturated bond functional groups of the 1,2-substituted ethylenes contained in (ta1), (ta2) and (tb1) was 24.6 mol%. The functional group equivalent of 1,2-substituted ethylene was calculated to be 783 (g / eq.) by (Mathematical formula 2).

[0250] Copolymer C-1 was soluble in toluene, xylene, tetrahydrofuran, dichloroethane or chloroform, and no gel formation was observed.

[0251] Analysis of each element of chlorine, bromine and iodine showed that the content rates were all lower than the detection limit (5 ppm).

[0252] Comparative Example 5

[0253] In a 1.0 L reactor, 2.97 moles (423.0 mL) of divinylbenzene, 0.70 moles (99.2 mL) of ethyl vinylbenzene, 0.33 moles (38.3 mL) of styrene, 0.13 moles (15.3 mL) of n-propyl acetate, and 330 mL of toluene were charged. A solution obtained by dissolving 24 millimoles of trifluoromethanesulfonic acid in 33 millimoles (3.8 mL) of n-propyl acetate was added at 50 °C, and the reaction was carried out for 7 hours. After stopping the polymerization solution with 7% aqueous sodium bicarbonate solution, the oil layer was washed 3 times with pure water. This reaction was poured into a large amount of methanol to form a white precipitate, and the white precipitate was recovered and the obtained polymer was weighed. It was confirmed that 547.8 g of copolymer C-2 was obtained.

[0254] The obtained copolymer C-1 was analyzed by GPC. As a result, Mn was 950, Mw was 13100, and Mw / Mn was 13.8. The vinyl equivalent of copolymer C-2 was measured, and the result was 158 (g / eq.). The number of unsaturated bond functional groups was calculated to be 6.01 by (Mathematical formula 1).

[0255] Based on the results of GC analysis, the respective structures contained in the copolymer are as described below.

[0256] Structural unit from divinylbenzene (a): 83.1 mol% (84.1 wt%)

[0257] Structural unit from ethyl vinylbenzene (b-1): 10.1 mol% (10.4 wt%)

[0258] Structural unit from styrene (b-2): 6.76 mol% (5.50 wt%)

[0259] In addition, for 1 1H-NMR analysis, the same operation as that for copolymer A-1 was carried out for analysis. Resonance lines obtained were also observed within the same range as that for copolymer A-1.

[0260] Resonance lines attributed to the aromatic rings in the structural units from the above (a), (b-1), and (b-2) were observed at the same positions as those for copolymer A-1, and the total integral value was 6.14.

[0261] In addition, resonance lines attributed to 1,2-substituted ethylenes of (ta1), (ta2), and (tb1) were also observed at the same positions as those for copolymer A. Analysis was carried out in the same manner as in Example 1, and as a result, the integral value was determined to be 0.25.

[0262] Based on the ratio of the above integral values, the proportion of the unsaturated bond functional groups derived from the vinyl groups contained in (a1) and (ta1) relative to the number of unsaturated bond functional groups is 79.8 mol%, and the proportion of the unsaturated bond functional groups derived from the 1,2-substituted ethylenes contained in (ta1), (ta2), and (tb1) is 20.2 mol%. The functional group equivalent of 1,2-substituted ethylene is calculated to be 781 (g / eq.) by (Mathematical formula 2).

[0263] Copolymer C-2 is soluble in toluene, xylene, tetrahydrofuran, dichloroethane, or chloroform, and no gel formation is observed.

[0264] The analysis of each element of chlorine, bromine, and iodine shows that the content rate is lower than the detection limit (5 ppm).

[0265] Comparative Example 6

[0266] Copolymer D was synthesized according to Example 2 described in Japanese Patent No. 4338951. That is, 0.29 mol (42.6 ml) of divinylbenzene, 0.012 mol (1.73 ml) of ethyl vinylbenzene, 11.0 ml of a dichloroethane solution (concentration: 0.063 mmol / ml) of 1-chloroethylbenzene (0.70 mmol), and 600 ml of dichloroethane and 100 ml of toluene (dielectric constant: 2.35) were placed in a 1.0 L flask. At 70 °C, 14.6 ml of a dichloroethane solution (concentration: 0.068 mmol / ml) of 1.00 mmol of SnCl4 was added, and the reaction was carried out for 30 minutes. After the polymerization reaction was stopped with a small amount of methanol bubbled with nitrogen, the reaction mixture was poured into a large amount of methanol at room temperature to form a white precipitate, and the white precipitate was recovered. The recovered white precipitate was washed with methanol, filtered, separated, dried, and weighed to obtain 48.3 g of copolymer D.

[0267] The copolymer D obtained was analyzed by GPC. As a result, Mn was 1850, Mw was 4650, and Mw / Mn was 2.51. The vinyl equivalent of copolymer D was measured, and the result was 132 (g / eq.). The number of unsaturated bond functional groups was calculated to be 14.02 by (Mathematical formula 1).

[0268] Based on the results of GC analysis, the structures contained in the copolymer are as described below.

[0269] Structural unit derived from divinylbenzene (a): 98.0 mol% (98.0 wt%)

[0270] Structural unit derived from ethyl vinylbenzene (b-1): 2.00 mol% (2.03 wt%)

[0271] In addition, for 1H-NMR analysis was performed in the same manner as for copolymer A for analysis. Resonance lines obtained were observed within the same range as for copolymer C-1.

[0272] Resonance lines attributable to the aromatic rings in the structural units from (a) and (b-1) above were observed at the same positions as for copolymer C-1, and the total integral value was 4.14.

[0273] In addition, resonance lines attributable to 1,2-substituted ethylenes of (ta1), (ta2), and (tb1) were also observed at the same positions as for copolymer C-1. Analysis was carried out in the same manner as in Example 1, and as a result, the integral value was determined to be 0.020.

[0274] Based on the ratio of the above integral values, the proportion of unsaturated bond functional groups derived from vinyl groups contained in (a1) and (ta1) relative to the number of unsaturated bond functional groups was calculated to be 98.0 mol%, and the proportion of unsaturated bond functional groups derived from 1,2-substituted ethylenes contained in (ta1), (ta2), and (tb1) was 2.00 mol%. The functional group equivalent of the number of 1,2-substituted ethylenes was calculated to be 37390 (g / eq.) by (mathematical formula 2).

[0275] Copolymer D was soluble in toluene, xylene, tetrahydrofuran, dichloroethane, or chloroform, and no gel formation was observed.

[0276] Analysis of each element of chlorine, bromine, and iodine was carried out. As a result, the contents of bromine and iodine were below the detection limit (5 ppm). On the other hand, the chlorine content was 1% or more.

[0277] Examples 2 and 3 and Comparative Examples 1 to 6

[0278] According to the compounding compositions described in Table 1, each copolymer composition varnish was obtained in the same manner as in Example 1. Using the obtained copolymer composition varnishes, physical properties were measured according to the procedures described in the above respective test methods. The results obtained are shown in Table 1.

[0279] Examples 4 to 7 and Comparative Examples 7 and 8

[0280] According to the compounding compositions described in Table 1, each copolymer composition varnish was obtained in the same manner as in Example 1. However, in each test method, physical properties were measured by changing only the following two points. That is, the method of homogenizing the mixture was changed to stirring using a mechanical stirrer, and 6) the measurement of the coefficient of linear expansion (CTE) of the cured product, and 7) the drying temperature and time of the films with the lowest melt viscosities (η1) and η2 were changed to 110 °C and 5 minutes. The results obtained are shown in Table 2.

[0281]

[0282]

[0283] Industrial Applicability

[0284] The soluble polyfunctional vinyl aromatic copolymer of the present invention can be processed into molding materials, sheets or films, and can be used as low dielectric materials, insulating materials, heat-resistant materials, structural materials, etc. that can meet the characteristics such as low dielectric constant, low water absorption, and high heat resistance in the fields of the electrical industry, aerospace and aircraft industries, etc. In particular, it can be applied to semiconductor-related materials or optical materials such as single-sided, double-sided, and multi-layer printed circuit boards, flexible printed circuit boards, and build-up substrates, as well as coatings, photosensitive materials, adhesives, sewage treatment agents, heavy metal capturers, ion exchange resins, antistatic agents, antioxidants, antifogging agents, rust inhibitors, anti-dyeing agents, fungicides, insecticides, medical materials, flocculants, surfactants, lubricants, binders for solid fuels, conductive treatment agents, etc.

[0285] The curable composition of the present invention has high dielectric properties, and can provide a cured product with high adhesion reliability even in a harsh environment. It has excellent resin fluidity, low linear expansion, and excellent wiring embedding flatness. Therefore, in the fields of the electrical and electronic industries, aerospace and aircraft industries, etc., as dielectric materials, insulating materials, heat-resistant materials, structural materials, etc., it can meet the urgent requirements of miniaturization and light weight in recent years, and provide a cured molded product without molding defects such as warping. Moreover, due to its excellent wiring embedding flatness and adhesion to different types of materials, it can realize a resin composition, a cured product or a material containing the same with excellent reliability.

Claims

1. A soluble polyfunctional vinyl aromatic copolymer, characterized in that, It is a polyfunctional vinyl aromatic copolymer containing structural units derived from a divinyl aromatic compound (a) and structural units derived from a monovinyl aromatic compound (b). The structural units derived from the divinyl aromatic compound (a) include a vinyl-containing unit represented by the following formula (a1), a 1,2-substituted ethylene-containing unit represented by the following formula (ta2), a crosslinked structural unit represented by the following formula (a2), and a structural unit containing both vinyl and 1,2-substituted ethylene represented by the following formula (ta1). The structural units derived from the monovinyl aromatic compound (b) include a structural unit represented by the following formula (b1) and a terminal unit containing 1,2-substituted ethylene represented by the following formula (tb1). The total number of unsaturated bond functional groups in one molecule is 2.1 or more and less than 4.0, where the total number of unsaturated bond functional groups does not include the unsaturated bond groups of the aromatic ring. The functional group equivalent of 1,2-substituted ethylene from the following formulas (ta1), (ta2), and (tb1) is 1000 or more, the number average molecular weight is 300 to 10,000, and the molecular weight distribution represented by the ratio of the weight average molecular weight to the number average molecular weight, i.e., Mw / Mn, is 50 or less. The soluble polyfunctional vinyl aromatic copolymer is soluble in toluene, xylene, tetrahydrofuran, dichloroethane, or chloroform and does not contain halogen-based elements other than fluorine as impurities at 5 ppm or more. In formula (a1), R 1 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms, In formula (a2), R 1 has the same meaning as in formula (a1). In formula (ta1), R 1 has the same meaning as formula (a1), In formula (ta2), R 1 has the same meaning as in formula (a1), In formula (b1), R 2 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms, and R 3 represents hydrogen or a hydrocarbon group having 1 to 12 carbon atoms. In formula (tb1), R 2 , R 3 has the same meaning as formula (b1).

2. A method for manufacturing a soluble polyfunctional vinyl aromatic copolymer, characterized in that, It is a method for manufacturing the soluble polyfunctional vinyl aromatic copolymer according to claim 1, wherein the divinyl aromatic compound (a) and the monovinyl aromatic compound (b) are reacted in the presence of a Lewis acid catalyst (d) and a Lewis base compound (e) that do not contain halogens other than fluorine. Relative to the total of (a) and (b), 18 mol% or more and less than 35 mol% of the divinyl aromatic compound (a) is used, and polymerization is carried out at a temperature of 85 to 120 °C.

3. A curable composition, characterized in that, It contains the soluble polyfunctional vinyl aromatic copolymer according to claim 1 and a radical polymerization initiator.

4. The curable composition according to claim 3, wherein The minimum melt viscosity η1 is 100 Pa·s or less, and the ratio of the melt viscosity η2 at a temperature of η1 + 5 °C is less than 5.

0.

5. The curable composition according to claim 3, wherein It further contains a thermosetting compound and / or a thermoplastic resin.

6. The curable composition according to claim 3, wherein, It further contains an inorganic filler.

7. A cured product obtained by curing the curable composition according to claim 3.

8. A film formed by shaping the curable composition according to claim 3 into a film form.

9. A curable composite material, characterized in that, It is a curable composite material composed of the curable composition according to claim 3 and a substrate, and contains the substrate in a proportion of 5 to 90% by weight.

10. A cured composite material, characterized in that, It is obtained by curing the curable composite material according to claim 9.

11. A laminate, characterized in that, It has a layer of the curable composite material according to claim 9 and a metal foil layer.

12. A metal foil with resin, characterized in that, A film formed by the curable composition according to claim 3 is provided on one side of the metal foil.

13. A varnish for a circuit board material, which is obtained by dissolving the curable composition according to claim 3 in an organic solvent.

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