Conjugated-diene copolymer, conjugated-diene copolymer composition, resin composition, cured object, resin film, prepreg, laminate, and material for electronic circuit board

Abstract

Provided is a conjugated-diene copolymer satisfying the following requirements (1) to (3). (Requirement (1)) The conjugated-diene copolymer comprises: a polymer block (A) including vinyl aromatic monomer units (a-1) having a radical-reactive group; a polymer block (B) consisting mainly of conjugated-diene monomer units (b); and a random polymer block (C) including the vinyl aromatic monomer units (a-1) having a radical-reactive group and the conjugated-diene monomer units (b) and consisting mainly of both vinyl aromatic monomer units (a) including the units (a-1) and the conjugated-diene monomer units (b). (Requirement (2)) The conjugated-diene copolymer has a number-average molecular weight higher than 40,000 but not higher than 150,000. (Requirement (3)) In the conjugated-diene copolymer, the content of all the vinyl aromatic monomer units (a) including the units (a-1) is 5-70 mass%.

Description

Conjugated diene copolymer, conjugated diene copolymer composition, resin composition, cured product, resin film, prepreg, laminate, and material for electronic circuit board

[0001] The present invention relates to a conjugated diene copolymer, a conjugated diene copolymer composition, a resin composition, a cured product, a resin film, a prepreg, a laminate, and a material for electronic circuit boards.

[0002] In recent years, with the remarkable progress in information network technology and the expansion of services utilizing information networks, electronic devices are required to have larger information capacity and faster processing speeds. To meet these demands, materials with low dielectric loss are required for the insulating layers of various substrates, such as printed circuit boards and flexible substrates.

[0003] In order to obtain materials with low dielectric loss, resin cured products have been studied and disclosed that are primarily composed of thermosetting resins obtained by radical curing, such as polyphenylene ether resins, which have low dielectric constants and / or low dielectric dissipation factors and excellent mechanical properties such as strength. However, the materials disclosed so far still have room for improvement in terms of low dielectric constants and low dielectric dissipation factors, and when used in printed circuit boards, they have the problem of limited information capacity and processing speed. Furthermore, in order to reduce transmission loss, metal foils, mainly copper foils, with low roughness are used as conductors. While using copper foils with low roughness can reduce transmission loss, they have the problem of tending to have poor adhesion to the insulating layer.

[0004] To address these problems, various rubber components have been proposed as modifiers for thermosetting resins. For example, Patent Document 1 discloses at least one elastomer selected from the group consisting of block copolymers of vinyl aromatic compounds and olefinic alkene compounds, hydrogenated products thereof, and homopolymers of vinyl aromatic compounds as modifiers for lowering the dielectric loss tangent and dielectric constant of polyphenylene ether resins. Patent Document 2 also discloses a styrene-based elastomer as a modifier for lowering the dielectric loss tangent and dielectric constant of epoxy resins.

[0005] JP 2021-147486 A JP 2020-15861 A

[0006] However, the resin compositions using the modifiers disclosed in Patent Documents 1 and 2 still have the problem of not being able to sufficiently achieve both low dielectric constant and low dielectric loss tangent, and heat resistance and adhesion to metal foil. In view of this problem, a technique of increasing the amount of rubber component to lower the dielectric constant, low dielectric loss tangent, and improve adhesion to metal foil has been known, but this technique has the problem of inducing an increase in viscosity during curing.

[0007] Therefore, an object of the present invention is to provide a conjugated diene-based copolymer, which can give a cured product having a low dielectric constant and a low dielectric loss tangent, and which also has excellent heat resistance and adhesion to metal foil, and a resin composition containing the conjugated diene-based copolymer.

[0008] As a result of intensive investigations aimed at solving the above-mentioned problems of the prior art, the present inventors have found that a cured product of a resin composition containing a conjugated diene copolymer having a predetermined structure has a low dielectric constant and a low dielectric loss tangent, and also has excellent heat resistance, and have thus completed the present invention.

[0009] [1] A conjugated diene copolymer satisfying the following conditions (1) to (3): (Condition (1)) The conjugated diene copolymer comprises a polymer block (A) containing a vinyl aromatic monomer unit (a-1) having a radical reactive group, a polymer block (B) mainly composed of a conjugated diene monomer unit (b), and a random polymer block (C) containing the vinyl aromatic monomer unit (a-1) having a radical reactive group and the conjugated diene monomer unit (b), and mainly composed of the vinyl aromatic monomer unit (a) containing the unit (a-1) and the conjugated diene monomer unit (b). (Condition (2)) The number-average molecular weight of the conjugated diene copolymer is more than 40,000 but not more than 150,000. (Condition (3)) The content of all vinyl aromatic monomer units (a) including the unit (a-1) in the conjugated diene copolymer is 5 to 70 mass%. [2] The conjugated diene copolymer according to [1], further satisfying the following condition (4): (Condition (4)) The number average molecular weight of the conjugated diene copolymer is more than 40,000 and not more than 100,000. [3] The conjugated diene copolymer according to [1] or [2], wherein the polymer block (A) further comprises a vinyl aromatic monomer unit (unit (a-2)) (excluding unit (a-1)), the polymer block (A) is mainly composed of a sum of the vinyl aromatic monomer unit (a-1) having a radical reactive group and the vinyl aromatic monomer unit (a-2), the total content of the unit (a-1) and the unit (a-2) in the conjugated diene copolymer is 5 to 70 mass%, and the random polymer block (C) further comprises a vinyl aromatic monomer unit (unit (a-2)) (excluding unit (a-1)), and the random polymer block (C) is mainly composed of a sum of the unit (a-1), the unit (a-2), and the conjugated diene monomer unit (b). [4] The conjugated diene copolymer according to any one of [1] to [3], wherein the conjugated diene monomer unit (b) is an acyclic conjugated diene monomer unit. [5] The conjugated diene copolymer according to any one of [1] to [4], wherein at least a part of the conjugated diene monomer units of the conjugated diene copolymer is hydrogenated.[6] The conjugated diene copolymer according to any one of [3] to [5] above, further satisfying the following condition (5): (Condition (5)) The mass ratio of the units (a-1) to the units (a-2) is (a-1) / (a-2)=30 / 70 to 99 / 1. [7] The conjugated diene copolymer according to any one of [1] to [6] above, wherein at least a portion of the conjugated diene monomer units of the conjugated diene copolymer are hydrogenated, and the hydrogenation rate is 98% or less. [8] The conjugated diene copolymer according to any one of [1] to [7] above, wherein at least a portion of the conjugated diene monomer units of the conjugated diene copolymer are hydrogenated, and the hydrogenation rate is 50% or more and 98% or less. [9] The conjugated diene copolymer according to any one of [1] to [8], wherein the conjugated diene copolymer has three or more ends.

[10] The conjugated diene copolymer according to any one of [1] to [9], wherein the conjugated diene copolymer has five or more ends.

[11] A conjugated diene copolymer composition comprising the conjugated diene copolymer (conjugated diene copolymer (D)) according to claim 1, and a conjugated diene copolymer (E) satisfying the following (conditions (6)) to (conditions (7)). (Condition (6)) The number average molecular weight is 40,000 or less. (Condition (7)) The copolymer has at least one polymer block selected from the group consisting of a polymer block (A) containing a vinyl aromatic monomer unit (a-1) having a radical reactive group, a random polymer block (C) containing the unit (a-1) and a conjugated diene monomer unit (b) and consisting mainly of the vinyl aromatic monomer unit (a) containing the unit (a-1) and the conjugated diene monomer unit (b), and a polymer block (B) consisting mainly of a conjugated diene monomer unit, and has the polymer block (A) and / or the random polymer block (C).

[12] The conjugated diene copolymer composition according to

[11] , wherein the polymer block (A) constituting the conjugated diene copolymer (E) further comprises a vinyl aromatic monomer unit (unit (a-2)) (excluding unit (a-1)), the polymer block (A) constituting the conjugated diene copolymer (E) is mainly composed of a sum of the vinyl aromatic monomer unit (a-1) having a radical reactive group and the vinyl aromatic monomer unit (a-2), and the random polymer block (C) constituting the conjugated diene copolymer (E) further comprises a vinyl aromatic monomer unit (unit (a-2)) (excluding unit (a-1)).

[13] The conjugated diene copolymer composition according to

[11] or

[12] , wherein the conjugated diene copolymer (E) further satisfies the following (condition (8)): (Condition (8)) The ratio (MnD / MnE) of the number average molecular weight (MnD) of the conjugated diene copolymer (D) to the number average molecular weight (MnE) of the conjugated diene copolymer (E) is greater than 2.

[14] A resin composition comprising: component (I): the conjugated diene copolymer according to any one of claims 1 to 10, or the conjugated diene copolymer composition according to any one of claims 11 to 13; and at least one component selected from the group consisting of the following components (II) to (III): component (II): a radical initiator; and component (III): a curable resin (excluding component (I)).

[15] The resin composition according to item

[14] , wherein component (III) is a radical curable resin having, as a reactive group, at least one reactive group selected from the group consisting of a vinyl group, a maleimide group, an allyl group, and a methacrylic group.

[16] A cured product of the conjugated diene copolymer described in any one of [1] to

[10] above.

[17] A cured product of the conjugated diene copolymer composition described in any one of

[11] to

[13] above.

[18] A cured product of the resin composition described in

[14] above.

[19] A resin film made of the resin composition described in

[14] above.

[20] A prepreg which is a composite of a substrate and the resin composition described in

[14] above.

[21] The prepreg described in

[20] above, wherein the substrate is glass cloth.

[22] A laminate comprising the resin film described in

[19] above and a metal foil.

[23] A material for electronic circuit boards, comprising the cured product described in

[18] above.

[24] A material for electronic circuit boards, comprising the resin film described in

[19] above.

[25] A material for electronic circuit boards, comprising the prepreg described in

[20] above.

[0010] According to the present invention, there are provided a conjugated diene-based copolymer and a resin composition containing the conjugated diene-based copolymer, which give a cured product having a low dielectric constant and a low dielectric loss tangent, and which also has excellent heat resistance and adhesion to metal foil.

[0011] Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. Note that the following present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content, and the present invention can be carried out in various modified forms within the scope of its gist.

[0012] [Conjugated Diene Copolymer] The conjugated diene copolymer of this embodiment is a conjugated diene copolymer satisfying the following conditions (1) to (3): (Condition (1)) The conjugated diene copolymer comprises a polymer block (A) containing a vinyl aromatic monomer unit (a-1) having a radical reactive group, a polymer block (B) mainly composed of a conjugated diene monomer unit (b), and a random polymer block (C) containing the vinyl aromatic monomer unit (a-1) having a radical reactive group and the conjugated diene monomer unit (b), and mainly composed of the vinyl aromatic monomer unit (a) containing the unit (a-1) and the conjugated diene monomer unit (b). (Condition (2)) The number-average molecular weight of the conjugated diene copolymer is more than 40,000 and not more than 150,000. (Condition (3)) The content of all vinyl aromatic monomer units (a) including the unit (a-1) in the conjugated diene copolymer is 5 to 70 mass%.

[0013] The conjugated diene copolymer of this embodiment can provide a cured product that has a low dielectric constant, a low dielectric loss tangent, and excellent heat resistance.

[0014] (Condition (1)) The conjugated diene copolymer of this embodiment has a polymer block (A) containing a vinyl aromatic monomer unit (a-1) (hereinafter, may be referred to as unit (a-1)) having a radical reactive group. The polymer block (A) is mainly composed of vinyl aromatic monomer units. That is, the polymer block (A) may be mainly composed of the unit (a-1), or may contain the unit (a-1) and vinyl aromatic monomer units (a-2) excluding the unit (a-1), and the total of these may be mainly composed of these. In this specification, the vinyl aromatic monomer units in the polymer block (A) may be collectively referred to as unit (a). Here, the term "mainly composed of" means that the amount of vinyl aromatic monomer units in the polymer block (A) is 70% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and more preferably 100% by mass (other copolymerization components are not intentionally included). From the viewpoint of reactivity, which will be described later, the content of the unit (a-1) in the polymer block (A) is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, still more preferably 60% by mass or more, still more preferably 70% by mass or more, particularly preferably 80% by mass or more, and particularly preferably 85% by mass or more.

[0015] The vinyl aromatic monomer unit (a-1) has a radical reactive group. The vinyl aromatic monomer unit having a radical reactive group refers to a structural unit derived from a radically reactive vinyl aromatic compound, which is produced by polymerization of a radically reactive vinyl aromatic compound. The "radical reactive group" is a chemical group that can generate free radicals and / or induce the formation of free radical species by the action of heat and / or light and / or free radical species of a radical initiator. Since the conjugated diene copolymer of this embodiment has the vinyl aromatic monomer unit (a-1) having a radical reactive group, the cured product of a resin composition using the conjugated diene copolymer of this embodiment tends to have excellent heat resistance.

[0016] The radical reactive group is not particularly limited as long as it generates free radicals, and may be any chemical group. After the monomers are polymerized to produce the conjugated diene copolymer, the radical reactive functional group exists in the conjugated diene copolymer, i.e., the radical reactive group is not consumed during polymerization and maintains its radical reactivity. The radical reactive group is not limited to the following. For example, chemical groups that generate free radicals primarily due to light and / or a radical initiator include benzophenone groups, benzoyl groups, groups containing an anthraquinone skeleton, and thioxanthone groups. Furthermore, chemical groups that generate free radicals primarily due to heat and / or light and / or a radical initiator include groups containing disulfide bonds and groups containing peroxy bonds. Furthermore, chemical groups that generate free radicals primarily due to heat and / or a radical initiator include benzyl carbons having at least one hydrogen substituent, thiol groups, vinyl groups, groups containing an alkoxyamine skeleton, and groups containing an azo bond. Furthermore, the chemical groups shown above may have other substituents or be bonded to other atomic groups as long as they generate free radical species. However, from the viewpoint of the dielectric performance of the cured product of the resin composition using the conjugated diene copolymer of this embodiment, a chemical group containing a benzyl carbon atom having at least one hydrogen substituent, which has low polarity, or a chemical group having a vinyl group is preferred.

[0017] Examples of the vinyl aromatic monomer having a radical reactive group that forms the vinyl aromatic monomer unit (a-1) having a radical reactive group include, but are not limited to, o-methylstyrene, p-methylstyrene, o-ethylstyrene, p-ethylstyrene, o-isopropylstyrene, para-isopropylstyrene, o-methyl-α-methylstyrene, p-methyl-α-methylstyrene, o-ethyl-α-methylstyrene, p-ethyl-α-methylstyrene, o-isopropyl-α-methylstyrene, para-isopropyl-α-methylstyrene, divinylbenzene, or any mixture thereof, with p-methylstyrene being preferred from the viewpoint of the reactivity described above. These may be used alone or in combination of two or more.

[0018] The polymer block (A) constituting the conjugated diene-based copolymer of this embodiment may contain a vinyl aromatic monomer unit (a-2) (excluding the unit (a-1); hereinafter, this may be referred to as unit (a-2)). In this case, the polymer block (A) is mainly composed of vinyl aromatic monomer units (a) that combine the vinyl aromatic monomer units (a-1) having a radical reactive group and the vinyl aromatic monomer units (a-2). Here, "mainly composed of vinyl aromatic monomer units (a-1) having a radical reactive group and vinyl aromatic monomer units (a-2) (excluding (a-1))" means that the total amount of the units (a-1) and the units (a-2) in the polymer block (A) is 70% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and more preferably 100% by mass (intentionally not including other copolymerization components). Furthermore, when the conjugated diene copolymer of this embodiment contains the units (a-1) and (a-2), the units (a-1) and (a-2) may be uniformly distributed or taperedly distributed in the polymer block (A). Furthermore, there may be a plurality of uniformly distributed portions and / or a plurality of taperedly distributed portions of the units (a-1) and (a-2). The vinyl aromatic monomer unit (a-2) refers to a structural unit derived from a vinyl aromatic compound in a copolymer produced by polymerization of a vinyl aromatic compound. Examples of the vinyl aromatic compound forming the unit (a-2) include, but are not limited to, styrene, 1,1-diphenylethylene, N,N-dimethyl-p-aminoethylstyrene, and N,N-diethyl-p-aminoethylstyrene. These may be used alone or in combination of two or more. The conjugated diene copolymer of the present embodiment has a polymer block (A) containing the unit (a-1), and thus the conjugated diene copolymer of the present embodiment has reactivity with component (III): a curable resin, which will be described later, and the resin composition of the present embodiment, which will be described later, can have a low dielectric loss tangent and a low dielectric constant, and the heat resistance tends to be improved.Furthermore, when the polymer block (A) has the unit (a-2), the reactivity of the conjugated diene copolymer of the present embodiment with the component (III): a curable resin, which will be described later, can be appropriately controlled.

[0019] The conjugated diene copolymer of this embodiment has a polymer block (B) (hereinafter, sometimes referred to as polymer block (B)) mainly composed of conjugated diene monomer units (units (b)). Here, "mainly composed of conjugated diene monomer units (b)" means that the total amount of the units (b) in the polymer block (B) is 70% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 100% by mass (intentionally not containing other copolymerization components). The conjugated diene monomer units (b) refer to structural units derived from a conjugated diene compound in a conjugated diene copolymer produced by polymerization of a conjugated diene compound. The conjugated diene compound is preferably a diolefin having a pair of conjugated double bonds and is acyclic. That is, the conjugated diene monomer units (b) are preferably acyclic conjugated diene monomer units. When the conjugated diene monomer unit (b) is an acyclic conjugated diene monomer unit, the flexibility of the conjugated diene copolymer of this embodiment tends to be improved, and the adhesiveness to metal foil tends to be improved. Examples of conjugated diene compounds include, but are not limited to, 1,3-butadiene, 2-methyl-1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 1,3-cyclohexadiene, isoprene, and the like, or mixtures thereof. From the viewpoint of availability, 1,3-butadiene, 2-methyl-1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-cyclohexadiene are preferred, and 1,3-butadiene is more preferred. These compounds may be used alone or in combination of two or more. The conjugated diene compounds may also be bio-derived conjugated diene compounds. By the conjugated diene copolymer of this embodiment having the polymer block (B), the conjugated diene copolymer of this embodiment becomes flexible, and the resin composition of this embodiment and a cured product made of the resin composition, which will be described later, become flexible, and the adhesion to metal foil tends to be improved.

[0020] The conjugated diene copolymer of this embodiment has a random polymer block (C) containing the vinyl aromatic monomer unit (a-1) having the radical reactive group and a conjugated diene monomer unit (unit (b)). The random polymer block (C) is mainly composed of the vinyl aromatic monomer unit (a) containing the unit (a-1) and the conjugated diene monomer unit (b). The random polymer block (C) may further contain a vinyl aromatic monomer unit (unit (a-2)) (excluding the unit (a-1)). In such a case, the random polymer block (C) is mainly composed of the unit (a-1), the unit (a-2), and the conjugated diene monomer unit (b). Here, "based on vinyl aromatic monomer units including vinyl aromatic monomer units (a-1) having a radical reactive group and the conjugated diene monomer units" means that the total amount of the units (a-1) and the units (b) in the polymer block (C), or the total amount of the units (a-1), the units (a-2), and the units (b) is 60% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, still more preferably 95% by mass or more, and still more preferably 100% by mass (other copolymerization components are not intentionally included).

[0021] The polymer block (B) mainly composed of the conjugated diene monomer unit (b) described above tends to have lower compatibility with the component (III): curable resin, described below, compared to the polymer block (A) and the random polymer block (C) containing the unit (a-1) and optionally the unit (a-2). Therefore, bonding with the component (III), described below, is less likely to occur, and heat resistance tends to be reduced. Therefore, by having the conjugated diene-based copolymer of this embodiment contain the random polymer block (C) containing the unit (b), the unit (a-1), and optionally the unit (a-2), it tends to be possible to achieve a balance between the flexibility and the reactivity with the component (III). From the viewpoint of the balance between flexibility and reactivity, the random polymer block (C) contains the unit (a-1) and the conjugated diene monomer unit (b), and optionally further contains the unit (a-2). The distribution state of the units (a-1) and the optionally contained units (a-2) in the polymer block (C) is not particularly limited, and the units (a-1) and (a-2) may be uniformly distributed or tapered in the random polymer block (C). Further, there may be a plurality of portions where the units (a-1) and (a-2) are uniformly distributed and / or a plurality of portions where the units (a-2) are tapered, and there may be a plurality of segments with different contents of the vinyl aromatic monomer units (a).

[0022] The composition ratios of the above-described macrostructure, the vinyl aromatic monomer unit (a-1) having a radical reactive group, the vinyl aromatic monomer unit (a-2) excluding the (a-1), and the conjugated diene monomer unit (b) in the conjugated diene copolymer of this embodiment can be measured by a method using a nuclear magnetic resonance (NMR) spectrometer (the method described in Y. Tanaka, et al., RUBBER CHEMISTRY and TECHNOLOGY 54, 685 (1981), hereinafter referred to as the "NMR method") using the conjugated diene copolymer before hydrogenation or the hydrogenated conjugated diene copolymer after hydrogenation as a sample.

[0023] (Conditions (2) and (4)) The conjugated diene copolymer of this embodiment has a number average molecular weight of more than 40,000 and not more than 150,000. The number average molecular weight can be determined by measuring the molecular weight of the peak in a chromatogram obtained by gel permeation chromatography (GPC) based on a calibration curve (prepared using the peak molecular weight of the standard polystyrene) obtained from the measurement of commercially available standard polystyrene. Specifically, the number average molecular weight can be measured by the method described in the Examples below. The resin films, prepregs, and laminates described below, as well as materials for electronic circuit boards containing the resin films, prepregs, or laminates, can generally be produced by dissolving the respective materials in an organic solvent, mixing, and molding them. Therefore, from the viewpoint of solubility in organic solvents, the number average molecular weight of the conjugated diene copolymer of this embodiment is 150,000 or less, preferably 130,000 or less, and more preferably 100,000 or less. From the viewpoint of handleability of the conjugated diene copolymer of this embodiment, the lower limit of the number average molecular weight is more than 40,000, preferably 45,000 or more, and more preferably 50,000 or more. When the number average molecular weight is more than 40,000, it is possible to prevent the conjugated diene copolymer from fusing with other conjugated diene copolymers, and good handleability tends to be obtained. The number average molecular weight of the conjugated diene copolymer of this embodiment can be controlled to be within the above-mentioned numerical range by adjusting polymerization conditions such as the amount of monomer added, timing of addition, polymerization temperature, and polymerization time.

[0024] (Condition (3)) In the conjugated diene copolymer of this embodiment, the content of all vinyl aromatic monomer units (a), including the vinyl aromatic monomer unit (a-1) having a radical reactive group, in the conjugated diene copolymer is 5 to 70 mass%. Furthermore, when the conjugated diene polymer block of this embodiment contains a vinyl aromatic monomer unit (a-2) (excluding the unit (a-1)), the vinyl aromatic monomer unit (a-2) is a vinyl aromatic monomer unit other than the vinyl aromatic monomer unit (a-1) having a radical reactive group, and therefore the total amount of the units (a-1) and the units (a-2) in the conjugated diene copolymer of this embodiment is 5 to 70 mass%. As described above, the units (a-1) and (a-2) tend to have better compatibility with the component (III) described below than the conjugated diene monomer unit (b) in terms of SP value. In contrast, the presence of the conjugated diene monomer unit (b) tends to make the conjugated diene copolymer of this embodiment more flexible and improve adhesion to metal foil. Therefore, from the viewpoint of the balance between the compatibility and adhesion, the content of all vinyl aromatic monomer units including the unit (a-1) in the conjugated diene copolymer of this embodiment, or the total amount of the unit (a-1) and the unit (a-2) is 5 to 70% by mass, preferably 10 to 70% by mass, more preferably 15 to 70% by mass, even more preferably 20 to 70% by mass, even more preferably 25 to 70% by mass, still more preferably 25 to 65% by mass, particularly preferably 25 to 60% by mass, and most preferably 25 to 55% by mass. The contents of the unit (a-1) and the unit (a-2) in the conjugated diene copolymer of this embodiment can be controlled within the above-mentioned ranges by adjusting the type, amount, timing of addition, and polymerization time of the monomers in the polymerization step.

[0025] Furthermore, from the viewpoint of the reactivity of the conjugated diene copolymer of this embodiment with the component (III) described below, the conjugated diene copolymer of this embodiment preferably has a mass ratio of the units (a-1) to the units (a-2) of (a-1) / (a-2) = 30 / 70 to 100 / 0. Incidentally, when (a-1) / (a-2) = 100 / 0, this means that the unit (a-2) is not contained. When the unit (a-2) is contained, the lower limit of (a-1) / (a-2) is more preferably 50 / 50 or more, even more preferably 60 / 40 or more, even more preferably 70 / 30 or more, still more preferably 80 / 20 or more, particularly preferably 90 / 10 or more, even more preferably 95 / 5 or more, even more preferably 98 / 2, and most preferably 99 / 1 or more. When the unit (a-2) is contained, the upper limit of (a-1) / (a-2) is more preferably 99 / 1 or less. When the content of the units (a-1) is 30% by mass or more and 99% by mass or less relative to the total of the units (a-1) and the units (a-2) (condition (5)), the conjugated diene-based copolymer of the present embodiment has sufficient reactivity, and the resin composition of the present embodiment, which will be described later, tends to have a low dielectric loss tangent, a low dielectric constant, and improved heat resistance.

[0026] (Hydrogenation Ratio) As described above, the conjugated diene copolymer of this embodiment has a polymer block (B) mainly composed of conjugated diene monomer units (b). It also has a random polymer block (C) containing conjugated diene monomer units (b) as a constituent element. In the conjugated diene copolymer of this embodiment, at least a portion of the conjugated diene monomer units (b) may be hydrogenated.

[0027] Recently, metal foils, particularly copper foils, used as conductors in various electronic devices tend to have low roughness in order to reduce scattering loss. Therefore, insulating layers are required to have high adhesion to low-roughness metal foils. The conjugated diene copolymer of this embodiment has aliphatic double bonds based on the conjugated diene monomer units, and such aliphatic double bonds are known to have higher radical reactivity than the vinyl aromatic monomer units (a-1) having the radical-reactive group. Therefore, bonding with the curable resin (component (III)) described below and bonding between the conjugated diene copolymers themselves result in a cured product with high crosslink density, which tends to improve the CTE. On the other hand, a decrease in the molecular weight between crosslink points tends to rigidify the cured product and reduce adhesion to the metal foil. Therefore, in order to control the reactivity based on the conjugated diene monomer units from the perspective of achieving both the above-mentioned CTE and adhesion to the metal foil, it is preferable that the double bonds of the conjugated diene monomer units (b) in the conjugated diene copolymer of this embodiment are hydrogenated. Specifically, the hydrogenation rate of the conjugated diene copolymer of this embodiment is preferably 50% or more, more preferably 60% or more, even more preferably 70% or more, still more preferably 75% or more, still more preferably 80% or more, particularly preferably 83% or more, and most preferably 85% or more. From the viewpoint of the CTE described above, the upper limit is preferably 98% or less, more preferably 96% or less.

[0028] A hydrogenation catalyst can be used in the hydrogenation reaction. Examples of the hydrogenation catalyst include, but are not limited to, (1) supported heterogeneous hydrogenation catalysts in which a metal such as Ni, Pt, Pd, or Ru is supported on carbon, silica, alumina, or diatomaceous earth; (2) so-called Ziegler-type hydrogenation catalysts in which a transition metal salt such as an organic acid salt or acetylacetone salt of Ni, Co, Fe, or Cr is used with a reducing agent such as an organoaluminum; and (3) homogeneous hydrogenation catalysts such as so-called organometallic complexes of organometallic compounds of Ti, Ru, Rh, Zr, or the like. Specific examples of the hydrogenation catalyst include the hydrogenation catalysts described in JP-B Nos. 42-8704, 43-6636, 63-4841, 1-37970, 1-53851, and 2-9041. Preferred hydrogenation catalysts include titanocene compounds and / or reducing organometallic compounds.

[0029] Examples of titanocene compounds that can be used include compounds described in JP-A-8-109219. Examples of titanocene compounds include, but are not limited to, compounds having at least one ligand with a (substituted) cyclopentadienyl skeleton, an indenyl skeleton, or a fluorenyl skeleton, such as biscyclopentadienyl titanium dichloride and monopentamethylcyclopentadienyl titanium trichloride. The titanocene compound may contain one or a combination of two of the above skeletons. Examples of reducing organometallic compounds include, but are not limited to, organic alkali metal compounds such as organolithium compounds, organomagnesium compounds, organoaluminum compounds, organoboron compounds, and organozinc compounds. These compounds may be used alone or in combination. The hydrogenation rate can be controlled to the above-mentioned level by adjusting the reaction temperature, reaction time, hydrogen supply amount, catalyst amount, and the like in the hydrogenation method. The temperature during the hydrogenation reaction is preferably 55 to 200°C, more preferably 60 to 170°C, and even more preferably 65 to 160°C. The pressure of hydrogen used in the hydrogenation reaction is 0.1 to 15 MPa, preferably 0.2 to 10 MPa, and more preferably 0.3 to 5 MPa. The hydrogenation reaction time is usually 3 minutes to 10 hours, and preferably 10 minutes to 5 hours. The hydrogenation reaction can be carried out using a batch process, a continuous process, or a combination thereof.

[0030] (Macrostructure of Conjugated Diene Copolymer) In terms of the reactivity and mobility of the conjugated diene copolymer with the curable resin (component (III) described below), the conjugated diene copolymer preferably has terminals that tend to be more reactive than the interior. From the viewpoint of reactivity, the conjugated diene copolymer preferably has a large number of terminals, preferably three or more, more preferably five or more. A large number of terminals increases the amount of reaction with the curable resin (component (III) described below), which tends to further improve the heat resistance of the resin composition of this embodiment. Furthermore, in terms of obtaining the aforementioned appropriate crosslink density, when the number of terminals is three or more, the conjugated diene copolymer of this embodiment preferably has a hydrogenation rate of 60% or more, more preferably 65% ​​or more, even more preferably 70% or more, and even more preferably 75% or more. The number of terminals of the conjugated diene copolymer of this embodiment can be controlled within the above-mentioned numerical range by using a predetermined branching agent in the polymerization step.

[0031] [Conjugated diene copolymer composition] The conjugated diene copolymer composition of this embodiment contains the conjugated diene copolymer of this embodiment described above and a conjugated diene copolymer (E) that satisfies the following (conditions (6)) to (conditions (7)). Here, in order to distinguish the conjugated diene copolymer of this embodiment from the conjugated diene copolymer (E), the conjugated diene copolymer of this embodiment may be referred to as a conjugated diene copolymer (D) in this specification.

[0032] Examples of methods for producing the conjugated diene copolymer composition include: (1) a method of solution polymerizing each of the components that form two or more peaks in a chromatogram obtained by GPC measurement, and mixing the solutions containing the polymers; (2) a method of mixing the components after removing the solvent and catalyst; (3) a method of adding a polymerization initiator in two stages during the polymerization reaction; (4) a method of adding a protic reagent such as an alcohol as a modifier, coupling agent, or polymerization terminator that reacts with the living terminals during the polymerization reaction in an amount that is insufficient relative to the living terminals to terminate the reaction of some of the living terminals; and (5) a method of adding a protic reagent such as an alcohol as a modifier or polymerization terminator in an equimolar amount to the living terminals after the polymerization reaction to terminate the reaction of all the living terminals, and then adding a new polymerization initiator and monomer to the solution and carrying out polymerization.

[0033] In the method (1), either a method in which polymerization solutions of each component before hydrogenation are mixed and then the hydrogenation reaction is carried out, or a method in which each component is hydrogenated and then the respective solutions are mixed, can be applied. The mixing ratio of each component can be controlled to a desired value by adjusting the concentration of each polymerization solution and the mixing amount of the solutions. In the method (3), the mixing ratio of each component can be controlled to a desired value by adjusting the feed rate of the vinyl aromatic compound and the conjugated diene compound, the amount of polymerization initiator added in two stages, the timing of the second-stage addition of the polymerization initiator, etc. In the method (4), the mixing ratio and structure of each component can be controlled as desired by adjusting the feed rate and feed composition of the vinyl aromatic compound and the conjugated diene compound, the amount of modifier or polymerization terminator added midway and the timing of addition, etc.

[0034] As in the above methods (1), (3), (4), and (5), mixing components that form two or more peaks in a chromatogram obtained by GPC measurement before desolvation enables the desolvation and finishing process to be carried out at a high rate. The above methods (3) and (4) make it possible to simultaneously produce component (I-X) having the highest number-average molecular weight and component (I-N) having the lowest number-average molecular weight, and therefore reduce the number of production steps compared to when component (I-X) and component (I-N) are produced separately, thereby improving production efficiency.

[0035] The coupling agent used in (4) can be any known one and is not particularly limited. Examples of bifunctional coupling agents include, but are not limited to, alkoxysilane compounds such as trimethoxysilane, triethoxysilane, tetramethoxysilane, tetraethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, dichlorodimethoxysilane, dichlorodiethoxysilane, trichloromethoxysilane, and trichloroethoxysilane; dihalogen compounds such as dichloroethane, dibromoethane, dimethyldichlorosilane, and dimethyldibromosilane; and acid esters such as methyl benzoate, ethyl benzoate, phenyl benzoate, and phthalic acid esters. In addition, any known one can be used as a trifunctional or higher polyfunctional coupling agent and is not particularly limited. Examples of the polyfunctional coupling agent having three or more functional groups include, but are not limited to, polyalcohols having three or more functional groups, polyhydric epoxy compounds such as epoxidized soybean oil, diglycidyl bisphenol A, and 1,3-bis(N-N'-diglycidylaminomethyl)cyclohexane, and compounds represented by the general formula R ４ -nSiX ｎ (wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 3 to 4), for example, methylsilyl trichloride, t-butylsilyl trichloride, silicon tetrachloride, and bromides thereof, etc., silicon halide compounds represented by the general formula R ４ -nSnX ｎ(wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 3 to 4), such as polyvalent halogen compounds such as methyltin trichloride, t-butyltin trichloride, and tin tetrachloride. Dimethyl carbonate, diethyl carbonate, etc. may also be used.

[0036] (Condition (6)) The number average molecular weight is 40,000 or less. (Condition (7)) The polymer has at least one polymer block selected from the group consisting of a polymer block (A) containing a vinyl aromatic monomer unit (a-1) having a radical reactive group, a random polymer block (C) containing the unit (a-1) and a conjugated diene monomer unit (b) and consisting mainly of the vinyl aromatic monomer unit (a) containing the unit (a-1) and the conjugated diene monomer unit (b), and a polymer block (B) consisting mainly of a conjugated diene monomer unit, and the polymer has the polymer block (A) and / or the random polymer block (C).

[0037] Recently, miniaturization of electronic circuit boards has been considered, and wiring has become increasingly dense. Therefore, in order for the insulating layer to cover the dense wiring when a conductor layer and an insulating layer are laminated and cured, it is preferable that the viscosity of the insulating layer when cured is low. From the viewpoint of the aforementioned low viscosity, it is preferable that the material of the insulating layer is a conjugated diene-based copolymer composition containing the conjugated diene-based copolymer (D) and the conjugated diene-based copolymer (E).

[0038] As described above (condition (6)), the conjugated diene copolymer (E) has a number average molecular weight of 40,000 or less. That is, it has a lower molecular weight than the conjugated diene copolymer (D). Therefore, by including the conjugated diene copolymer (E), the conjugated diene copolymer composition of this embodiment tends to have a lower viscosity. From the viewpoint of the aforementioned lower viscosity, the number average molecular weight of the conjugated diene copolymer (E) is 40,000 or less.

[0039] The ratio (MnD / MnE) of the number average molecular weight (MnE) of the conjugated diene copolymer (E) to the number average molecular weight (MnD) of the conjugated diene copolymer (D) is preferably greater than 2 (condition (8)), more preferably 2.3 or greater, even more preferably 2.5 or greater, more preferably 2.7 or greater, still more preferably 3.0 or greater, and particularly preferably 3.3 or greater. This tends to lower the viscosity of the conjugated diene copolymer composition of this embodiment.

[0040] As described above, the number average molecular weight (MnE) of the conjugated diene copolymer (E) is 40,000 or less, preferably MnE = 35,000 or less, more preferably 30,000 or less. While there is no particular lower limit, a smaller number average molecular weight results in a smaller molecular weight between crosslinking points during reaction with the curable resin (component (III) described below), making it difficult to form an appropriate crosslink density, and the resin composition of this embodiment tends to have a smaller effect of lowering the dielectric constant and / or dielectric loss tangent. From the viewpoint of lowering the dielectric constant and / or dielectric loss tangent, the number average molecular weight of the conjugated diene copolymer (E) is preferably 2,000 or more, more preferably 2,500 or more, even more preferably 3,000 or more, and even more preferably 3,500 or more.

[0041] As described above, the conjugated diene copolymer (E) has a lower molecular weight than the conjugated diene copolymer (D) in order to reduce the viscosity of the conjugated diene copolymer composition of this embodiment. Low-molecular-weight copolymers are more susceptible to molecular motion than high-molecular-weight copolymers, and therefore, if they remain as unreacted components in a cured product, the effect of reducing the dielectric constant and / or the dielectric loss tangent tends to be reduced. In view of the above, in order to improve the reactivity between the conjugated diene copolymers (E) themselves and / or with the conjugated diene copolymer (D), and / or with the curable resin (component (III) described later), the conjugated diene copolymer (E) has the polymer block (A) and / or the random polymer block (C) containing a vinyl aromatic monomer unit (a-1) having a radical-reactive group, and optionally has the polymer block (B) (condition (7)). When the conjugated diene copolymer (E) has the polymer block (A) and / or the polymer block (C) containing the unit (a-1), the conjugated diene copolymer (E) has sufficient reactivity, and the proportion of low molecular weight components present in the cured product of the present embodiment decreases, which tends to achieve both a high viscosity during curing, a low dielectric constant, and a low dielectric loss tangent.

[0042] The mass ratio of the conjugated diene copolymer (D) to the conjugated diene copolymer (E) in the conjugated diene copolymer composition is preferably conjugated diene copolymer (D) / conjugated diene copolymer (E)=50 / 50 to 90 / 10, more preferably 50 / 50 to 85 / 15, and even more preferably 50 / 50 to 80 / 20, from the viewpoints of lowering the dielectric constant, lowering the dielectric loss tangent, improving adhesion to metal foil, and lowering the viscosity.

[0043] Furthermore, when the conjugated diene copolymer (E) has the polymer block (A) and / or the polymer block (C), and the number average molecular weight of the conjugated diene copolymer (E) is preferably 10,000 or more, more preferably 15,000 or more, and even more preferably 20,000 or more, the ratio of the conjugated diene copolymer (D) / the conjugated diene copolymer (E) is preferably 30 / 70 to 80 / 20, more preferably 35 / 65 to 75 / 25. When the conjugated diene copolymer (E) does not have the polymer block (A) and / or the polymer block (C) and the content of the conjugated diene copolymer (E) in the conjugated diene copolymer composition is more than 70% by weight, the reactivity of the conjugated diene copolymer with the component (III) described below is low, and therefore the conjugated diene copolymer composition of this embodiment tends to have a lower dielectric constant and a lower dielectric loss tangent. Furthermore, when the number-average molecular weight of the conjugated diene copolymer (E) is 10,000 or less and the content of the conjugated diene copolymer (E) in the conjugated diene copolymer composition is more than 70 wt %, the flexibility of the cured product described below tends to decrease, and the adhesion to metal foil tends to decrease. That is, from the viewpoint of achieving a low dielectric constant, a low dielectric loss tangent, and both high adhesion to metal foil and low viscosity, the conjugated diene copolymer (E) in the conjugated diene copolymer composition preferably has the polymer block (A) and / or the polymer block (C), has a number-average molecular weight of 10,000 or more, and the mass ratio of the conjugated diene copolymer (D) to the conjugated diene copolymer (E) in the conjugated diene copolymer composition is preferably 30 / 70 to 80 / 20.

[0044] The conjugated diene copolymer (E) may be one in which the polymer block (A) constituting the conjugated diene copolymer (E) further contains a vinyl aromatic monomer unit (a-2) (excluding the unit (a-1)) in addition to the vinyl aromatic monomer unit (a-1) having a radical reactive group. In such a case, the polymer block (A) mainly consists of the unit (a-1) and the unit (a-2). The conjugated diene copolymer (E) may be one in which the random polymer block (C) further contains a vinyl aromatic monomer unit (a-2) (excluding the unit (a-1)) in addition to the vinyl aromatic monomer unit (a-1) having a radical reactive group.

[0045] (Vinyl Bond Content) In the conjugated diene copolymer (D) and the low-molecular-weight conjugated diene copolymer (E) of this embodiment, the conjugated diene monomer units (b) may include units (b-1) (hereinafter sometimes referred to as units (b-1)) derived from a 1,2-bond and / or a 3,4-bond, and units (b-2) (hereinafter sometimes referred to as units (b-2)) derived from a 1,4-bond. The units (b-1) tend to have higher flexibility than the units (b-2). Therefore, from the viewpoint of adhesion to the metal foil, when the total content of the polymer block (B) mainly composed of conjugated diene monomer units and the random polymer block (C) is taken as 100%, the content of the units (b-1) derived from a 1,2-bond and / or a 3,4-bond is preferably 25% or more, more preferably 30% or more, and even more preferably 35% or more. The content of the unit (b-1) can be controlled within the above-mentioned range by using a regulator such as a polar compound during polymerization, and can be calculated by the method described in the examples below.

[0046] Examples of the adjuster include, but are not limited to, tertiary amine compounds and ether compounds. It is preferable to use a tertiary amine compound. The tertiary amine compound is a compound represented by the general formula: R1R2R3N (wherein R1, R2, and R3 are a hydrocarbon group having 1 to 20 carbon atoms or a hydrocarbon group having a tertiary amino group). Examples of the tertiary amine compound include, but are not limited to, trimethylamine, triethylamine, tributylamine, N,N-dimethylaniline, N-ethylpiperidine, N-methylpyrrolidine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetraethylethylenediamine, 1,2-dipiperidinoethane, trimethylaminoethylpiperazine, N,N,N',N",N"-pentamethylethylenetriamine, and N,N'-dioctyl-p-phenylenediamine.

[0047] [Method for Producing Conjugated Diene-Based Copolymer] The conjugated diene-based copolymer (D) and the low-molecular-weight conjugated diene-based copolymer (E) of the present embodiment can be produced, for example, by living anionic polymerization in a hydrocarbon solvent using a polymerization initiator such as an organic alkali metal compound.

[0048] Examples of hydrocarbon solvents include, but are not limited to, aliphatic hydrocarbons such as n-butane, isobutane, n-pentane, n-hexane, n-heptane, and n-octane; alicyclic hydrocarbons such as cyclohexane, cycloheptane, and methylcycloheptane; and aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene. Polymerization initiators include various organic alkali metal compounds, such as aliphatic hydrocarbon alkali metal compounds, aromatic hydrocarbon alkali metal compounds, and organic amino alkali metal compounds, which are generally known to have anionic polymerization activity for conjugated diene compounds and vinyl aromatic compounds. Examples of alkali metals include lithium, sodium, and potassium. Examples of organic alkali metal compounds include aliphatic and aromatic hydrocarbon lithium compounds having 1 to 20 carbon atoms, including compounds containing one lithium atom per molecule, and dilithium, trilithium, and tetralithium compounds containing multiple lithium atoms per molecule. Examples of organic alkali metal compounds include, but are not limited to, n-propyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, n-pentyllithium, n-hexyllithium, benzyllithium, phenyllithium, tolyllithium, a reaction product of diisopropenylbenzene and sec-butyllithium, and a reaction product of divinylbenzene, sec-butyllithium, and a small amount of 1,3-butadiene. Furthermore, 1-(t-butoxy)propyllithium, as disclosed in U.S. Patent No. 5,708,092, and lithium compounds into which one to several molecules of isoprene monomer have been inserted to improve solubility, siloxy group-containing alkyllithiums such as 1-(t-butyldimethylsiloxy)hexyllithium, as disclosed in British Patent No. 2,241,239, amino group-containing alkyllithiums such as diisopropylamidelithium and hexamethyldisilazidelithium, as disclosed in U.S. Patent No. 5,527,753, and aminolithiums such as lithium diisopropylamidelithium and hexamethyldisilazidelithium can also be used.

[0049] Conventional methods can be used to polymerize a vinyl aromatic compound and a conjugated diene compound using an organic alkali metal compound as a polymerization initiator. The polymerization method may be, for example, batch polymerization, continuous polymerization, or a combination of these. Batch polymerization is preferred to obtain a uniform polymer block. The polymerization temperature is preferably 0°C to 180°C, more preferably 30°C to 150°C. The polymerization time varies depending on the conditions, but is usually within 48 hours, preferably 0.1 to 10 hours. Furthermore, an inert gas atmosphere such as nitrogen gas is preferred as the polymerization atmosphere. The polymerization pressure is not particularly limited, as long as it is set within a pressure range that can maintain the monomer and solvent in a liquid phase within the above temperature range. Furthermore, care must be taken to prevent impurities, such as water, oxygen, and carbon dioxide, that may inactivate the catalyst and living polymer from being introduced into the polymerization system.

[0050] Furthermore, at the end of the polymerization step, a required amount of a bifunctional or higher coupling agent may be added to carry out a coupling reaction, but the coupling rate is preferably 40% or less, more preferably 30% or less, and even more preferably 20% or less, and it is even more preferable that no coupling agent is included. As the bifunctional coupling agent, any conventionally known agent can be used, and there is no particular limitation. Examples of bifunctional coupling agents include, but are not limited to, alkoxysilane compounds such as trimethoxysilane, triethoxysilane, tetramethoxysilane, tetraethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, dichlorodimethoxysilane, dichlorodiethoxysilane, trichloromethoxysilane, and trichloroethoxysilane; dihalogen compounds such as dichloroethane, dibromoethane, dimethyldichlorosilane, and dimethyldibromosilane; and acid esters such as methyl benzoate, ethyl benzoate, phenyl benzoate, and phthalic acid esters. As the trifunctional or higher polyfunctional coupling agent, any conventionally known agent can be used, and there is no particular limitation. Examples of the polyfunctional coupling agent having three or more functional groups include polyalcohols having three or more functional groups, polyhydric epoxy compounds such as epoxidized soybean oil, diglycidyl bisphenol A, and 1,3-bis(N-N'-diglycidylaminomethyl)cyclohexane; ４ -nSiX ｎ (wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 3 to 4), such as methylsilyl trichloride, t-butylsilyl trichloride, silicon tetrachloride, and brominated compounds thereof; ４ -nSnX ｎ (wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 3 to 4), such as polyvalent halogen compounds such as methyltin trichloride, t-butyltin trichloride, and tin tetrachloride. Dimethyl carbonate, diethyl carbonate, etc. may also be used.

[0051] The conjugated diene copolymer (D) and the low-molecular-weight conjugated diene copolymer (E) of the present embodiment are subjected to a hydrogenation reaction, if necessary, and the hydrogenation reaction can be carried out by a known method using a known hydrogenation catalyst.

[0052] The solution of the conjugated diene copolymer (D) of the present embodiment and the low-molecular-weight conjugated diene copolymer (E) obtained as described above can be subjected to removal of catalyst residues as needed to separate the conjugated diene copolymer from the solution.

[0053] The polymerization initiator used in producing a conjugated diene copolymer by anionic living polymerization and the compound containing a metal atom in the hydrogenation catalyst used in the hydrogenation reaction described above tend to react with moisture in the air during a desolvation process or the like to generate a specific metal compound, which remains in the conjugated diene copolymer. As described above, materials for electronic circuit boards preferably include a process in which each material is dissolved in an organic solvent and impurities such as the metal compound are removed by filtration or the like. During filtration, metal compounds tend to clog filters such as meshes, resulting in reduced productivity. Furthermore, when these metal compounds are contained in the cured product of this embodiment, the dielectric constant and dielectric loss tangent tend to increase, and further, ion migration tends to occur easily in electronic material applications.

[0054] Examples of metal compounds that may remain in the conjugated diene copolymer of this embodiment include compounds of metals contained in the polymerization initiator and hydrogenation catalyst, such as oxides of various atoms such as titanium oxide, amorphous titanium oxide, orthotitanic acid, metatitanic acid, titanium hydroxide, nickel hydroxide, nickel monoxide, lithium oxide, lithium hydroxide, cobalt oxide, and cobalt hydroxide, and composite oxides of various atoms and different metals such as lithium titanate, barium titanate, strontium titanate, nickel titanate, and nickel-iron oxide. From the viewpoint of productivity described above, the amount of remaining metal compounds in the conjugated diene copolymer (D) and the low-molecular-weight conjugated diene copolymer (E) of this embodiment is preferably 150 ppm or less, more preferably 130 ppm or less, even more preferably 100 ppm or less, and even more preferably 90 ppm or less, in terms of the amount of residual metal. In particular, from the viewpoint of particle size, the Co content is preferably 80 ppm or less, more preferably 60 ppm or less, even more preferably 40 ppm or less, still more preferably 20 ppm or less, more preferably 10 ppm or less, even more preferably 5 ppm or less, and still more preferably 2 ppm or less. Also, from the viewpoint of lowering the dielectric constant, lowering the dielectric loss tangent, and making ion migration less likely to occur, the residual metal content is preferably 80 ppm or less, more preferably 70 ppm or less, even more preferably 60 ppm or less, and still more preferably 50 ppm or less.

[0055] The method for reducing the amount of residual metal in the conjugated diene copolymer (D) and the low-molecular-weight conjugated diene copolymer (E) of this embodiment can be any conventionally known method, and is not particularly limited. Examples include a method of adding water and carbon dioxide gas after the hydrogenation reaction of the conjugated diene copolymer to neutralize the hydrogenation catalyst residue; and a method of adding an acid in addition to water and carbon dioxide gas to neutralize the hydrogenation catalyst residue. Specifically, the method described in Japanese Patent Application No. 2014-557427 can be applied. Even when these methods for reducing the amount of residual metal are used, water containing hydroxides of metal compounds is mixed in during the desolvation process of the conjugated diene copolymer, and therefore, the conjugated diene copolymer of this embodiment generally contains approximately 1 to 15 ppm of residual metal. Therefore, it is preferable to remove 20% or more of the amount of metal added to the conjugated diene copolymer, more preferably 30% or more, even more preferably 40% or more, even more preferably 50% or more, and even more preferably 60% or more.

[0056] Furthermore, the amount of residual metal in the conjugated diene copolymer (D) and the low-molecular-weight conjugated diene copolymer (E) of this embodiment can be reduced by reducing the amounts of the polymerization initiator and hydrogenation catalyst added, but reducing the amount of polymerization initiator increases the molecular weight of the conjugated diene copolymer, and if the molecular weight falls outside the preferred molecular weight range described above, the strength of the cured product tends to decrease. Furthermore, when performing a hydrogenation reaction, reducing the amount of hydrogenation catalyst increases the hydrogenation reaction time and the hydrogenation reaction temperature, which tends to significantly reduce productivity.

[0057] Examples of methods for separating the solvent when recovering the conjugated diene copolymer include a method in which a polar solvent that is a poor solvent for the conjugated diene copolymer, such as acetone or alcohol, is added to the reaction solution after hydrogenation to precipitate and recover the conjugated diene copolymer; a method in which the reaction solution is poured into hot water with stirring and the solvent is removed by steam stripping to recover the copolymer; and a method in which the conjugated diene copolymer solution is directly heated to distill off the solvent.

[0058] The hydrogenated conjugated diene copolymer may contain various stabilizers such as phenol-based stabilizers, phosphorus-based stabilizers, sulfur-based stabilizers, and amine-based stabilizers.

[0059] The conjugated diene copolymer of this embodiment may have a "polar group" (excluding the radical reactive group of the vinyl aromatic monomer unit (a-1) having the radical reactive group) to the extent that the dielectric performance is not impaired. Examples of the "polar group" include, but are not limited to, a hydroxyl group, a carboxyl group, a carbonyl group, a thiocarbonyl group, an acid halide group, an acid anhydride group, a carboxylic acid group, a thiocarboxylic acid group, an aldehyde group, a thioaldehyde group, a carboxylic acid ester group, an amide group, a sulfonic acid group, a sulfonate ester group, a phosphoric acid group, a phosphoric acid ester group, an amino group, an imino group, a nitrile group, a pyridyl group, a quinoline group, an epoxy group, a thioepoxy group, a sulfide group, an isocyanate group, an isothiocyanate group, a silicon halide group, a silanol group, an alkoxy silicon group, a tin halide group, a boronic acid group, a boron-containing group, a boronate salt group, an alkoxy tin group, and a phenyl tin group. The "polar group" can be formed using a modifying agent.

[0060] Examples of the modifying agent include, but are not limited to, tetraglycidyl meta-xylenediamine, tetraglycidyl-1,3-bisaminomethylcyclohexane, ε-caprolactone, δ-valerolactone, 4-methoxybenzophenone, γ-glycidoxyethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyldimethylphenoxysilane, bis(γ-glycidoxypropyl)methylpropoxysilane, 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, N,N′-dimethylpropyleneurea, N-methylpyrrolidone, maleic acid, maleic anhydride, maleic anhydride imide, fumaric acid, itaconic acid, acrylic acid, methacrylic acid, glycidyl methacrylate, and crotonic acid.

[0061] The method for forming the "polar group" can be any known method and is not particularly limited. Examples include a melt-kneading method and a method in which each component is dissolved or dispersed in a solvent or the like and reacted. Other examples include an anionic living polymerization method in which a polymerization initiator having a functional group or an unsaturated monomer having a functional group is polymerized, a method in which a modifier that forms or contains a functional group is added to the living terminal to perform a modification, and a method in which a conjugated diene copolymer is reacted with an organic alkali metal compound such as an organolithium compound (metallation reaction), and then a block polymer to which the organic alkali metal has been added is subjected to an addition reaction with a modifier having a functional group.

[0062] [Resin Composition] The resin composition of this embodiment contains the above-described conjugated diene copolymer of this embodiment or the conjugated diene copolymer composition of this embodiment (a conjugated diene copolymer composition containing the conjugated diene copolymer (D) and the conjugated diene copolymer (E)) (component (I)), and at least one component selected from the group consisting of the following components (II) to (III): Component (II): Radical initiator Component (III): Curable resin (excluding component (I)) The resin composition of this embodiment may also contain the following components (IV), (V), and (VI): Component (IV): Flame retardant Component (V): Filler Component (VI): Crosslinking aid

[0063] (Component (II): Radical Initiator) As the radical initiator, conventionally known ones can be used. As the radical initiator, a thermal radical initiator can be used. Examples of the thermal radical initiator include, but are not limited to, hydroperoxides such as diisopropylbenzene hydroperoxide (Percumyl P), cumene hydroperoxide (Percumyl H), and t-butyl hydroperoxide (Perbutyl H), α,α-bis(t-butylperoxy-m-isopropyl)benzene (Perbutyl P), dicumyl peroxide (Percumyl D), 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane (Perhexa 25B), t-butylcumyl peroxide (Perbutyl C), di-t-butyl peroxide (Perbutyl D), 2,5-dimethyl- Examples of suitable peroxides include dialkyl peroxides such as 2,5-bis(t-butylperoxy)hexyne-3 (Perhexyne 25B) and t-butylperoxy-2-ethylhexanoate (Perbutyl O), ketone peroxides, peroxyketals such as n-butyl-4,4-di-(t-butylperoxy)valerate (Perhexa V), diacyl peroxides, peroxydicarbonates, and organic peroxides such as peroxyesters, and azo compounds such as 2,2-azobisisobutylnitrile, 1,1'-(cyclohexane-1-1-carbonitrile), 2,2'-azobis(2-cyclopropylpropionitrile), and 2,2'-azobis(2,4-dimethylvaleronitrile). These compounds may be used alone or in combination of two or more.

[0064] (Component (III): Curable Resin) Component (III): curable resin refers to a resin that undergoes a polymerization reaction upon heating or the like to form a polymer network structure. From the perspective of the aforementioned polymerization reaction, the curable resin has multiple reactive groups. While the polymerization reaction is not particularly limited, curing by radical reaction and addition reaction or curing by radical reaction is preferred from the perspective of lowering the dielectric loss tangent and dielectric constant. That is, component (III): curable resin is preferably a radical-curable resin. Curing by condensation reaction tends to require reactive groups with higher polarity than radical reactions, and tends to be less effective in lowering the dielectric loss tangent and dielectric constant. A reactive group that causes curing by radical reaction is a chemical group that can generate free radicals and / or induce the formation of free radical species due to the action of heat and / or light and / or free radical species of a radical initiator. For example, chemical groups that generate free radicals mainly due to light and / or a radical initiator include a benzophenone group, a benzoyl group, a group containing an anthraquinone skeleton, and a thioxanthone group. Furthermore, examples of chemical groups that generate free radicals in response to heat and / or light and / or a radical initiator include groups containing a disulfide bond and groups containing a peroxy bond, and examples of chemical groups that generate free radicals mainly in response to heat and / or a radical initiator include benzyl carbon having at least one hydrogen substituent, thiol groups, vinyl groups, groups containing an alkoxyamine skeleton, groups containing an azo bond, maleimide groups, allyl groups, and methacryl groups, etc. From the viewpoint of radical reactivity, vinyl groups, maleimide groups, allyl groups, and methacryl groups are preferred.

[0065] (Ratio of Components (I) to (III)) By optimizing the SP value, the component (I): conjugated diene copolymer or conjugated diene copolymer composition tends to have a better dielectric constant and dielectric dissipation factor as a single unit than the component (III): curable resin, specifically a resin having a vinyl group, a maleimide group, an allyl group, or a methacryl group. Therefore, from the viewpoint of reducing the dielectric constant and dielectric dissipation factor of the resin composition of this embodiment, the mass ratio of components (I) and (III) in the resin composition of this embodiment is preferably component (I) / component (III) = 40 / 60 to 90 / 10, more preferably 50 / 50 to 85 / 15, and even more preferably 55 / 45 to 80 / 20. Furthermore, it is preferable that component (II): a radical initiator is not contained from the viewpoint of reducing the dielectric constant and / or the dielectric loss tangent of the resin composition of the present embodiment, but it is preferable to adjust the amount added as appropriate, taking into consideration the balance between the reduction in the dielectric constant and the dielectric loss tangent depending on the radical reactivity, curing temperature, and curing time of components (I) and (III), the heat resistance, the adhesion to the metal foil, and further the CTE.

[0066] (Component (IV): Flame Retardant) The resin composition of this embodiment may further contain a flame retardant as component (IV). The flame retardant contained as an additive to component (I) the conjugated diene copolymer or the conjugated diene copolymer composition has the same meaning as component (IV) of the resin composition. Examples of flame retardants include, but are not limited to, halogen-based flame retardants such as bromine compounds, phosphorus-based flame retardants such as aromatic compounds, and flame retardants containing aromatic bromine compounds such as metal hydroxides, alkyl sulfonates, antimony trioxide, aluminum hydroxide, magnesium hydroxide, zinc borate, hexabromobenzene, decabromodiphenylethane, 4,4-dibromobiphenyl, and ethylenebistetrabromophthalimide. These flame retardants may be used alone or in combination of two or more. The flame retardants also include so-called flame retardant assistants, which have low flame retardancy when used alone but exhibit a synergistic effect when used in combination with other flame retardants.

[0067] (Component (V): Filler) The resin composition of this embodiment may further contain a filler as component (V). The filler contained as an additive to component (I) the conjugated diene copolymer or the conjugated diene copolymer composition has the same meaning as component (V) of the resin composition. Examples of fillers include, but are not limited to, inorganic fillers such as silica, calcium carbonate, magnesium carbonate, magnesium hydroxide, aluminum hydroxide, calcium sulfate, barium sulfate, carbon black, glass fiber, glass beads, glass balloons, glass flakes, graphite, titanium oxide, potassium titanate whiskers, carbon fiber, alumina, kaolin clay, silicic acid, calcium silicate, quartz, mica, talc, clay, zirconia, potassium titanate, alumina, and metal particles; and organic fillers such as wood chips, wood powder, pulp, and cellulose nanofibers. These may be used alone or in combination. The shape of these fillers is not particularly limited and may be scaly, spherical, granular, powdery, irregular, or the like. The inclusion of a filler tends to improve the CTE, and silica is preferred as the filler. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica.

[0068] Fillers and flame retardants may be used that have been previously surface-treated with a surface treatment agent such as a silane coupling agent. Examples of surface treatment agents include fluorine-containing silane coupling agents, aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, alkoxysilanes, organosilazane compounds, and titanate coupling agents. These may be used alone or in combination.

[0069] (Component (VI) Crosslinking Auxiliary Agent) As the crosslinking auxiliary, a low molecular weight compound having at least two structures having a reactive group can be used. A low molecular weight compound having at least two structures having a reactive group also has the function of reacting with component (I) and / or component (III) to cure the resin composition. Examples of compounds having at least two structures having a reactive group include, but are not limited to, allyl monomers such as triallyl isocyanurate (Taikyu, manufactured by Mitsubishi Chemical Corporation), 1,2-bis(4-vinylphenyl)ethane, tris(2-hydroxyethyl) isocyanurate, diallyl fumarate, diallyl adipate, triallyl citrate, and diallyl hexahydrophthalate.

[0070] (Other Additives) The resin composition and / or cured product of this embodiment may contain other additives. The other additives are not particularly limited as long as they are commonly used in the formulation of resin compositions and / or cured products. Examples of other additives include, but are not limited to, pigments and / or colorants such as carbon black and titanium oxide; lubricants such as stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, and ethylene bisstearamide; mold release agents; plasticizers such as organic polysiloxanes, fatty acid esters such as phthalates, adipates, and azelaates, and mineral oils; antioxidants such as hindered phenols and phosphorus-based heat stabilizers; hindered amine light stabilizers; benzotriazole ultraviolet absorbers; antistatic agents; organic fillers; thickeners; antifoaming agents; leveling agents; resin additives such as adhesion promoters; other additives, or mixtures thereof. From the viewpoint of achieving the aforementioned low dielectric constant and low dielectric loss tangent, it tends to be preferable that the resin composition of the present embodiment does not contain a pigment, a colorant, a lubricant, a release agent, or an antistatic agent.

[0071] The resin composition in this embodiment may be a melt-kneaded mixture of the components, or a mixture of the components dissolved in a solvent and stirred (hereinafter referred to as "varnish"). However, from the viewpoint of ease of handling, varnish is preferred. Examples of solvents constituting the varnish include, but are not limited to, ketones such as acetone, methyl ethyl ketone (MEK), cyclohexanone, and γ-butyrolactone; acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, carbitol acetate, and diethyl glycol monoacerate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; and amide solvents such as dimethylformamide, dimethylacetamide (DMAc), and N-methylpyrrolidone. The solvents may be used alone or in combination of two or more.

[0072] (Method for Producing Resin Composition) The method for producing the resin composition of this embodiment is not particularly limited, and known methods can be used. For example, a method of melt-kneading each component using a general mixer such as a Banbury mixer, a single-screw extruder, a twin-screw extruder, a co-kneader, or a multi-screw extruder, or a method of dissolving or dispersing and mixing each component and then removing the solvent by heating, etc. are mentioned. From the viewpoint of processability into a molded article suitable for use as a material for electronic circuit boards, such as a prepreg or a resin film, which will be described later, a method of dissolving or dispersing and mixing each component and then removing the solvent by heating is preferred.

[0073] [Cured Product] The cured product of this embodiment includes the conjugated diene copolymer of this embodiment described above. The cured product of this embodiment is a cured product of the conjugated diene copolymer, conjugated diene copolymer composition, or resin composition of this embodiment. The cured product of this embodiment can be obtained by subjecting the conjugated diene copolymer, conjugated diene copolymer composition, or resin composition of this embodiment to a curing reaction at any temperature and for any time. This concept encompasses not only completely cured products, but also partially cured products containing uncured components (semi-cured products). In the process for producing the laminate described below, a step of further curing the cured product may be carried out. The reaction temperature in the curing step of the cured product of this embodiment is preferably 80°C or higher, more preferably 100°C or higher, and even more preferably 120°C or higher. The reaction time is preferably 10 to 240 minutes, more preferably 20 to 230 minutes, and even more preferably 30 to 220 minutes. When the resin composition of this embodiment is a varnish, the curing reaction is preferably carried out after removing the solvent. The drying may be carried out by a conventionally known method such as heating or hot air blowing, and is preferably carried out at a temperature lower than the curing reaction temperature. The drying is carried out so that the amount of solvent in the cured product is preferably 10% by mass or less, more preferably 5% by mass or less.

[0074] [Resin Film] The resin film of this embodiment includes the resin composition of this embodiment. The resin film of this embodiment can be obtained, for example, by spreading a varnish made of the resin composition of this embodiment onto a suitable support to form a uniform thin film, drying it, and removing the solvent. This resin film can be wound into a roll and stored. The resin film of this embodiment may be laminated with a predetermined protective film. In such a case, the resin film can be used by peeling off the protective film. Examples of the support include films made of plastic materials, metal foils, release papers, etc. Examples of films made of plastic materials that serve as supports include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polycarbonates, acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimides, etc., with polyethylene terephthalate and polyethylene naphthalate being preferred from the standpoints of availability and cost. Examples of metal foils include copper foil and aluminum foil, with copper foil being preferred. The copper foil may be a foil made of a single metal such as copper, or a foil made of an alloy of copper and another metal (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.). The surface of the support that is to be bonded to the resin composition layer may be subjected to a matte treatment, a corona treatment, an antistatic treatment, or a release treatment.

[0075] [Prepreg] The prepreg of this embodiment includes a substrate and the resin composition of this embodiment impregnated or coated on the substrate. That is, the prepreg of this embodiment is a composite of the resin composition of this embodiment and the substrate. The prepreg can be obtained, for example, by impregnating a substrate such as glass cloth with the varnish of the resin composition of this embodiment described above, followed by removing the solvent by the drying method described above. Examples of substrates include various glass cloths such as roving cloth, cloth, chopped mat, and surfacing mat; asbestos cloth, metal fiber cloth, and other synthetic or natural inorganic fiber cloths; woven or nonwoven fabrics obtained from liquid crystal fibers such as wholly aromatic polyamide fiber, wholly aromatic polyester fiber, and polybenzoxazole fiber; natural fiber cloths such as cotton cloth, linen cloth, and felt; natural cellulose-based substrates such as carbon fiber cloth, kraft paper, cotton paper, and cloth obtained from paper-glass blend yarn; and polytetrafluoroethylene porous film. However, glass cloth is preferred from the viewpoint of dielectric performance. These substrates can be used alone or in combination of two or more. The proportion of solids made up of the resin composition of this embodiment in the prepreg is preferably 30 to 80% by mass, more preferably 40 to 70% by mass. When the proportion of solids made up of the resin composition is 30% by mass or more, the prepreg tends to have better insulation reliability when used for electronic substrates, etc. When the proportion is 80% by mass or less, the prepreg tends to have better mechanical properties such as rigidity when used for electronic substrates, etc.

[0076] [Laminate] The laminate of this embodiment includes the resin film and metal foil described above. The laminate of this embodiment can also include the cured prepreg and metal foil described above. The laminate of this embodiment can be produced, for example, by laminating a resin film made of the resin composition of this embodiment onto a predetermined substrate to form a resin layer and obtain a prepreg. Then, the resin layer is heated and pressurized to flatten it, thereby obtaining a cured prepreg. Finally, a predetermined wiring layer made of metal foil is further formed on the resin layer. In step (a), the method for laminating the resin film onto the substrate is not particularly limited. Examples of suitable methods include lamination using a multi-stage press, a vacuum press, a normal pressure laminator, or a laminator that applies heat and pressure under vacuum. A method using a laminator that applies heat and pressure under vacuum is preferred. When using this laminator to obtain an electronic circuit board using the laminate of this embodiment, even if the electronic circuit board has a fine wiring circuit on its surface, the resin can fill the spaces between the circuits without voids. Furthermore, lamination may be performed by a batch method or a continuous method using a roll or the like. Examples of the substrate include, but are not limited to, glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, polyphenylene ether-based substrates, and fluororesin substrates. The surface of the substrate on which the resin layer is to be laminated may be pre-roughened, and the number of substrate layers is not limited. In step (b), the resin film and substrate laminated in step (a) are heated and pressurized to be flattened. The conditions for step (b) can be adjusted as desired depending on the type of substrate and the composition of the resin film, but preferred ranges for step (b) are a temperature of 100 to 300°C, a pressure of 0.2 to 20 MPa, and a time of 30 to 180 minutes. In step (c), a predetermined wiring layer made of metal foil is further formed on the resin layer produced by heating and pressurizing the resin film and substrate. The method for forming the wiring layer is not particularly limited, and includes conventionally known methods, such as subtractive etching and semi-additive methods.The subtractive method is a method in which an etching resist layer corresponding to the desired pattern shape is formed on a metal layer, and then a development process is performed to dissolve and remove the metal layer from the areas where the resist has been removed using a chemical solution, thereby forming the desired wiring. The semi-additive method is a method in which a metal coating is formed on the surface of a resin layer using an electroless plating method, a plating resist layer corresponding to the desired pattern is formed on the metal coating, a metal layer is then formed using an electrolytic plating method, and the unnecessary electroless plating layer is then removed using a chemical solution, etc., to form the desired wiring layer. Furthermore, holes such as via holes may be formed in the resin layer as needed. The method for forming the holes is not particularly limited, and conventionally known methods can be used. Examples of methods for forming the holes include NC drills, carbon dioxide lasers, UV lasers, YAG lasers, and plasma.

[0077] [Metal-Clad Laminate] The laminate of the present embodiment described above may be in the form of a plate or a flexible laminate. The laminate of the present embodiment may be a metal-clad laminate. The metal-clad laminate is obtained by laminating and curing the resin composition of the present embodiment or the prepreg of the present embodiment with a metal foil, with a portion of the metal foil removed. The metal-clad laminate preferably has a configuration in which a cured product of the prepreg (also referred to as a "cured product composite") and a metal foil are laminated and adhered together, and is suitable for use as a material for electronic circuit boards. Examples of metal foil include aluminum foil and copper foil, and among these, copper foil is preferred due to its low electrical resistance. The cured product of the prepreg to be combined with the metal foil may be one or more sheets, and depending on the application, metal foil is laminated on one or both sides of the cured product to form a laminate. Examples of methods for producing the metal-clad laminate include forming a prepreg composed of the resin composition of this embodiment and a substrate, overlaying the prepreg on a metal foil, and then curing the resin composition to obtain a metal-clad laminate in which the cured prepreg and the metal foil are laminated. One particularly preferred application of the metal-clad laminate is a printed wiring board. The printed wiring board is preferably prepared by removing at least a portion of the metal foil from the metal-clad laminate. The printed wiring board can be produced by a pressure-heat molding method using the prepreg of this embodiment described above. The substrate can be the same as that described above for the prepreg. By containing the resin composition of this embodiment, the printed wiring board has excellent strength and electrical properties (low dielectric constant and low dielectric tangent), and can suppress fluctuations in electrical properties due to environmental changes, as well as excellent insulation reliability and mechanical properties.

[0078] [Material for Electronic Circuit Board] The material for electronic circuit board of this embodiment includes a cured product of the resin composition of this embodiment. The material for electronic circuit board of this embodiment can be produced using the resin composition and / or varnish of this embodiment described above. The material for electronic circuit board of this embodiment includes at least one selected from the group consisting of a cured product of the resin composition described above, a resin film containing the resin composition of this embodiment or its cured product, and a prepreg which is a composite of a substrate and a resin composition. The material for electronic circuit board of this embodiment can be used as a printed wiring board having a resin-coated metal foil.

[0079] Hereinafter, the present embodiment will be described in detail with reference to specific examples and comparative examples, but the present invention is not limited to the following examples and comparative examples.

[0080] The methods for identifying the structure and measuring the physical properties of the conjugated diene copolymer or conjugated diene copolymer composition (component (I)) used in the following Examples and Comparative Examples are shown below.

[0081] [Methods for identifying the structure of conjugated diene copolymers and measuring their physical properties] ((1) Content of vinyl aromatic monomer units in conjugated diene copolymers) Using a conjugated diene copolymer before hydrogenation, the contents of the vinyl aromatic monomer units (a-1) having a radical reactive group and the vinyl aromatic monomer units (a-2) (excluding the units (a-1)) in the conjugated diene copolymer were measured using a nuclear magnetic resonance spectrometer (manufactured by BRUKER, DPX-400).

[0082] (2) Amount of Vinyl Bonds in Conjugated Diene Copolymer The amount of vinyl bonds in a conjugated diene copolymer before hydrogenation was measured using an infrared spectrophotometer (FT / IR-230, manufactured by JASCO Corporation). The amount of vinyl bonds in the conjugated diene copolymer was calculated by the Hampton method. This value was taken as the content of units derived from 1,2-bonds and / or 3,4-bonds, when the total content of the polymer block (B) and the random polymer block (C) in the component (I) conjugated diene copolymer was taken as 100%.

[0083] (3) Number Average Molecular Weight of Conjugated Diene Copolymer) The number average molecular weight of the conjugated diene copolymer of component (I) before modification and hydrogenation was measured by GPC [apparatus: LC-10 (manufactured by Shimadzu Corporation), column: TSKgel GMHXL (4.6 mm × 30 cm)]. Tetrahydrofuran was used as the solvent. The measurement was carried out at a temperature of 35°C. The number average molecular weight was determined by using the molecular weight of the peak in the chromatogram and a calibration curve (prepared using the peak molecular weight of the standard polystyrene) obtained from the measurement of a commercially available standard polystyrene. When there are multiple peaks in the chromatogram, the number average molecular weight was determined from the molecular weight of each peak and the composition ratio of each peak (determined from the area ratio of each peak in the chromatogram).

[0084] (4) Hydrogenation Rate of Double Bonds of Conjugated Diene Monomer Units of Conjugated Diene Copolymer) Using the hydrogenated conjugated diene copolymer, the hydrogenation rate of double bonds of the conjugated diene monomer units was measured using a nuclear magnetic resonance spectrometer (manufactured by BRUKER, DPX-400).

[0085] (Ratio of radical polymer block (C) in conjugated diene copolymer, ratio of unit (a-1) in polymer block (C), ratio of unit (a-2) in polymer block (C), ratio of unit (b) in polymer block (C)) Each time the vinyl aromatic compound (styrene and / or p-methylstyrene) and / or the conjugated diene compound (butadiene) constituting each conjugated diene copolymer block was added to the reaction vessel, a sample of the polymerization solution was taken before the addition. Approximately 20 mL of the sampled polymer solution was injected into a sealed 100 mL bottle containing 0.50 mL of n-propylbenzene as an internal standard and approximately 20 mL of toluene, to prepare a measurement sample. The measurement sample was analyzed using a gas chromatograph (Shimadzu Corporation: GC-14B) equipped with a backed column loaded with Apiezon grease. The residual monomer amounts in the polymer solution were determined from previously obtained calibration curves for butadiene monomer, styrene monomer, and p-methylstyrene, confirming that the polymerization rate of butadiene monomer and / or styrene monomer and / or p-methylstyrene was 100%. Therefore, the composition ratios of the radical polymer block (C) rate, the unit (a-1) rate in polymer block (C), the unit (a-2) rate in polymer block (C), and the unit (b) rate in polymer block (C) in the conjugated diene copolymer were the same as the mass ratio of the added vinyl aromatic compound and conjugated diene compound. The polymerization rate of butadiene was measured at a constant temperature of 90°C, while the polymerization rate of styrene was measured under conditions of 90°C (10-minute hold) to 150°C (10°C / min) temperature increase.

[0086] [Materials for Conjugated Diene Copolymer, Conjugated Diene Copolymer Composition, and Resin Composition] (Preparation of Hydrogenation Catalyst) The hydrogenation catalyst used in producing the conjugated diene copolymer in the Examples and Comparative Examples described below was prepared by the following method. A reaction vessel equipped with a stirrer was purged with nitrogen, and 1 liter of dried and purified cyclohexane was charged thereto. Next, 100 mmol of bis(η5-cyclopentadienyl)titanium dichloride was added. While thoroughly stirring, an n-hexane solution containing 200 mmol of trimethylaluminum was added, and the mixture was allowed to react at room temperature for approximately 3 days. This yielded a hydrogenation catalyst.

[0087] (Component (I): Conjugated diene copolymer and conjugated diene copolymer composition) Component (I): conjugated diene copolymer constituting the resin composition, and each of the conjugated diene copolymers constituting the conjugated diene copolymer composition combining two types of conjugated diene copolymers were prepared as follows. The structure and physical properties of each conjugated diene copolymer are shown in Tables 1 to 4. The constituent components and the amount of each component of each conjugated diene copolymer composition are shown in Tables 5 to 7. In the tables, (A) represents a polymer block (A) mainly composed of vinyl aromatic monomer units. (B) represents a polymer block (B) mainly composed of conjugated diene monomer units. (C) represents a random polymer block (C) composed of vinyl aromatic monomer units and conjugated diene monomer units.

[0088] Example 1: Conjugated Diene Copolymer (D1) Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 7.5 parts by mass of styrene and 7.5 parts by mass of p-methylstyrene was added. Next, 0.19 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.5 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 15 minutes. Next, a cyclohexane solution containing 60 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 45 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 7.5 parts by mass of styrene and 7.5 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 15 minutes. Next, a cyclohexane solution containing 2.5 parts by mass of styrene, 2.5 parts by mass of p-methylstyrene, and 5 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 10 minutes. Thereafter, methanol was added to terminate the polymerization reaction, thereby obtaining a conjugated diene copolymer. The conjugated diene copolymer obtained as described above had a content of 17.5% by mass of the unit (a-1), 17.5% by mass of the unit (a-2), and a number average molecular weight of 5.0×10 ４The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 49%. The hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the conjugated diene copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain conjugated diene copolymer (D1). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene copolymer (D1). The hydrogenation rate was 97%.

[0089] Example 2: Conjugated diene copolymer (D2) Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 3.7 parts by mass of styrene and 11.3 parts by mass of p-methylstyrene was added. Next, 0.19 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.5 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 15 minutes. Next, a cyclohexane solution containing 60 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 45 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 3.7 parts by mass of styrene and 11.3 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 15 minutes. Next, a cyclohexane solution containing 1.25 parts by mass of styrene, 3.75 parts by mass of p-methylstyrene, and 5 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 10 minutes. Methanol was then added to terminate the polymerization reaction, yielding a conjugated diene copolymer. The conjugated diene copolymer obtained as described above had 26.3% by mass of units (a-1), 8.75% by mass of units (a-2), and a number average molecular weight of 5.0 × 10 ４The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 51%. The hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the conjugated diene copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 0.75 hours to obtain conjugated diene copolymer (D2). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene copolymer (D2). The hydrogenation rate was 45%.

[0090] Example 3 Conjugated Diene Copolymer (D3) The same procedure as for the conjugated diene copolymer (D2) was carried out, except that the hydrogenation reaction time was changed to 1 hour. The conjugated diene copolymer (D3) obtained as described above had 26.3% by mass of units (a-1), 8.75% by mass of units (a-2), and a number-average molecular weight of 5.0 × 10 ４ The molecular weight distribution was 1.10, the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) was 50%, and the hydrogenation rate was 55%.

[0091] Example 4 Conjugated Diene Copolymer (D4) The same procedure as for the conjugated diene copolymer (D2) was carried out, except that the hydrogenation reaction time was changed to 1.5 hours. The conjugated diene copolymer (D4) obtained as described above had a content of 26.3% by mass of units (a-1), 8.75% by mass of units (a-2), and a number-average molecular weight of 5.0 × 10 ４ The molecular weight distribution was 1.10, the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) was 50%, and the hydrogenation rate was 97%.

[0092] Example 5: Conjugated diene copolymer (D5) Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 0.7 parts by mass of styrene and 14.3 parts by mass of p-methylstyrene was added. Next, 0.19 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.5 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 15 minutes. Next, a cyclohexane solution containing 60 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 45 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 0.7 parts by mass of styrene and 14.3 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 15 minutes. Next, a cyclohexane solution containing 0.25 parts by mass of styrene, 4.75 parts by mass of p-methylstyrene, and 5 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 10 minutes. Methanol was then added to terminate the polymerization reaction, and 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the conjugated diene polymer (D5), thereby obtaining a conjugated diene copolymer (D5). The conjugated diene copolymer (D5) obtained as described above had 33.3% by mass of units (a-1), 1.7% by mass of units (a-2), and a number average molecular weight of 5.1 x 10 ４ The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 51%.

[0093] Example 6: Conjugated diene copolymer (D6) To the conjugated diene copolymer (D5) obtained by the same procedure as in Example 5, the hydrogenation catalyst prepared as above was added in an amount of 90 ppm (Ti standard) per 100 parts by mass of the conjugated diene copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 0.75 hours to obtain a conjugated diene copolymer (D6). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene copolymer (D6). The conjugated diene copolymer (D6) obtained as described above had 33.3% by mass of units (a-1), 8.75% by mass of units (a-2), and a number average molecular weight of 5.1 × 10 ４ The molecular weight distribution was 1.7, the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) was 50%, and the hydrogenation rate was 45%.

[0094] Example 7 Conjugated Diene Copolymer (D7) The same procedure as for the conjugated diene copolymer (D6) was carried out, except that the hydrogenation reaction time was changed to 1 hour. The conjugated diene copolymer (D7) obtained as described above had 33.3% by mass of units (a-1), 1.7% by mass of units (a-2), and a number-average molecular weight of 5.1 × 10 ４ The molecular weight distribution was 1.10, the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) was 51%, and the hydrogenation rate was 55%.

[0095] Example 8: Conjugated diene copolymer (D8) The same procedure as for the conjugated diene copolymer (D6) was carried out, except that the hydrogenation reaction time was changed to 1.5 hours. The conjugated diene copolymer (D8) obtained as described above had 33.3% by mass of units (a-1), 1.7% by mass of units (a-2), and a number average molecular weight of 5.1 × 10 ４ The molecular weight distribution was 1.10, the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) was 51%, and the hydrogenation rate was 97%.

[0096] Example 9: Conjugated diene copolymer (D9) The same procedure as for the conjugated diene copolymer (D6) was carried out, except that the hydrogenation reaction time was changed to 1.75 hours. The conjugated diene copolymer (D9) obtained as described above had 33.3% by mass of units (a-1), 1.7% by mass of units (a-2), and a number-average molecular weight of 5.1 × 10 ４ The molecular weight distribution was 1.10, the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) was 50%, and the hydrogenation rate was 99.5%.

[0097] Example 10: Conjugated diene copolymer (D10) Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 1.2 parts by mass of styrene and 23.8 parts by mass of p-methylstyrene was added. Next, 0.16 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.5 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 20 minutes. Next, a cyclohexane solution containing 45 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 45 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 1.2 parts by mass of styrene and 23.8 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 15 minutes. Next, a cyclohexane solution containing 0.25 parts by mass of styrene, 4.75 parts by mass of p-methylstyrene, and 5 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 10 minutes. Methanol was then added to terminate the polymerization reaction. The conjugated diene copolymer obtained as described above had 52.3% by mass of units (a-1), 7.7% by mass of units (a-2), and a number average molecular weight of 5.1 × 10 ４The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 49%. The hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the conjugated diene copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain conjugated diene copolymer (D10). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene polymer (D10). The hydrogenation rate was 97%.

[0098] Example 11: Conjugated Diene Copolymer (D11) Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 1.9 parts by mass of styrene and 5.6 parts by mass of p-methylstyrene was added. Next, 0.16 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.6 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 7 minutes. Next, a cyclohexane solution containing 55 parts by mass of butadiene, 1 part by mass of styrene, and 19 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 45 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 1.9 parts by mass of styrene and 5.6 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 7 minutes. Next, a cyclohexane solution containing 10 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 10 minutes. Thereafter, methanol was added to terminate the polymerization reaction. The conjugated diene copolymer obtained as described above had a content of 33.3% by mass of the unit (a-1), 1.7% by mass of the unit (a-2), and a number average molecular weight of 5.0×10 ４The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 50%. The hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the conjugated diene copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain conjugated diene copolymer (D11). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene polymer (D11). The hydrogenation rate was 97%.

[0099] Example 12 Conjugated Diene Copolymer (D12) The same procedure as for the conjugated diene copolymer (D11) was carried out, except that n-butyllithium was used in an amount of 0.093 parts by mass relative to 100 parts by mass of the total monomers. The conjugated diene copolymer (D12) obtained as described above had a content of 33.3% by mass of units (a-1), 1.7% by mass of units (a-2), and a number-average molecular weight of 10.0 × 10 ４ The molecular weight distribution was 1.10, the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) was 49%, and the hydrogenation rate was 97%.

[0100] Example 13: Conjugated Diene Copolymer (D13) Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 0.5 parts by mass of styrene and 9.5 parts by mass of p-methylstyrene was added. Next, 0.16 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.6 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 10 minutes. Next, a cyclohexane solution containing 25 parts by mass of butadiene, 1.7 parts by mass of styrene, and 33.3 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 45 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 0.5 parts by mass of styrene and 9.5 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 10 minutes. Next, a cyclohexane solution containing 20 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 15 minutes. Methanol was then added to terminate the polymerization reaction. The conjugated diene copolymer obtained as described above had 52.3% by mass of units (a-1), 2.7% by mass of units (a-2), and a number average molecular weight of 5.1 × 10 ４ The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 49%. The hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the conjugated diene copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain conjugated diene copolymer (D13). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene copolymer (D13). The hydrogenation rate was 97%.

[0101] Example 14: Conjugated diene copolymer (D14) Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 0.5 parts by mass of styrene and 9.5 parts by mass of p-methylstyrene was added. Next, 0.16 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.6 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 10 minutes. Next, a cyclohexane solution containing 10 parts by mass of butadiene, 1.7 parts by mass of styrene, and 33.3 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 35 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 0.5 parts by mass of styrene and 9.5 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 10 minutes. Next, a cyclohexane solution containing 35 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 20 minutes. Methanol was then added to terminate the polymerization reaction. The conjugated diene copolymer obtained as described above had 52.3% by mass of units (a-1), 2.7% by mass of units (a-2), and a number average molecular weight of 5.0 × 10 ４ The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 49%. The hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the conjugated diene copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain conjugated diene copolymer (D14). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene copolymer (D14). The hydrogenation rate was 97%.

[0102] Example 15: Conjugated Diene Copolymer (D15) Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 11.3 parts by mass of styrene and 3.8 parts by mass of p-methylstyrene was added. Next, 0.19 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.5 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 15 minutes. Next, a cyclohexane solution containing 60 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 45 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 11.3 parts by mass of styrene and 3.8 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 15 minutes. Next, a cyclohexane solution containing 3.7 parts by mass of styrene, 1.3 parts by mass of p-methylstyrene, and 5 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 10 minutes. Methanol was then added to terminate the polymerization reaction, yielding a conjugated diene copolymer. The conjugated diene copolymer obtained as described above had a content of 8.75% by mass of units (a-1), 6.25% by mass of units (a-2), and a number average molecular weight of 5.0 × 10 ４ The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 49%. The hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the conjugated diene copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain conjugated diene copolymer (D15). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene copolymer (D15). The hydrogenation rate was 97%.

[0103] Example 16: Conjugated diene copolymer (D22) The same procedure as for the conjugated diene copolymer (D8) was carried out, except that n-butyllithium was used in an amount of 0.0889 parts by mass relative to 100 parts by mass of the total monomers. The conjugated diene copolymer (D22) obtained as described above had a content of 33.3% by mass of units (a-1), 1.7% by mass of units (a-2), and a number average molecular weight of 10.5 × 10 ４ The molecular weight distribution was 1.10, the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) was 51%, and the hydrogenation rate was 97%.

[0104] <Example 63-1: Conjugated diene copolymer (D23) for Example 63 described below> As described below, in the conjugated diene copolymer composition (X22) of Example 63-3, the conjugated diene copolymer (D23) and the conjugated diene copolymer (E13) were prepared in one reactor, and a conjugated diene copolymer composition (X22) consisting of these was obtained. The physical properties of the conjugated diene copolymer (D23) are shown in Table 2.

[0105] <Example 64-1: Conjugated diene copolymer (D24) for Example 64 described below> As described below, in the conjugated diene copolymer composition (X23) of Example 64-3, the conjugated diene copolymer (D24) and the conjugated diene copolymer (E14) were prepared in one reactor, and a conjugated diene copolymer composition (X23) consisting of these was obtained. The physical properties of the conjugated diene copolymer (D24) are shown in Table 2.

[0106] Example 65-1: Conjugated diene copolymer (D25) for Example 65 described below> As described below, in the conjugated diene copolymer composition (X24) of Example 65-3, the conjugated diene copolymer (D25) and the conjugated diene copolymer (E15) were prepared in one reactor, and a conjugated diene copolymer composition (X24) consisting of these was obtained. The physical properties of the conjugated diene copolymer (D25) are shown in Table 2.

[0107] <Production Example 1: Conjugated Diene Copolymer (E1)> Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 11.5 parts by mass of styrene and 11.5 parts by mass of p-methylstyrene was added. Next, 0.80 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.3 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 15 minutes. Next, a cyclohexane solution containing 38 parts by mass of butadiene, 19.5 parts by mass of styrene, and 19.5 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 50 minutes. Thereafter, methanol was added to terminate the polymerization reaction, and a conjugated diene copolymer was obtained. The conjugated diene copolymer obtained as described above had a content of 31% by mass of units (a-1), 31% by mass of units (a-2), and a number average molecular weight of 1.0×10 ４ The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 50%. The hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the conjugated diene copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain a conjugated diene copolymer (E1). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene polymer (E1). The hydrogenation rate was 97%.

[0108] <Production Example 2: Conjugated diene copolymer (E2)> Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 5.8 parts by mass of styrene and 17.3 parts by mass of p-methylstyrene was added. Next, 0.80 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.3 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 15 minutes. Next, a cyclohexane solution containing 38 parts by mass of butadiene, 9.8 parts by mass of styrene, and 29.3 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 50 minutes. Thereafter, methanol was added to terminate the polymerization reaction, and a conjugated diene copolymer was obtained. The conjugated diene copolymer obtained as described above had a content of 46.5% by mass of units (a-1), 15.5% by mass of units (a-2), and a number average molecular weight of 1.0×10 ４ The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 50%. The hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the conjugated diene copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain conjugated diene copolymer (E2). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene polymer (E2). The hydrogenation rate was 97%.

[0109] <Production Example 3: Conjugated Diene Copolymer (E3)> Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 1.2 parts by mass of styrene and 21.9 parts by mass of p-methylstyrene was added. Next, 0.80 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.3 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 15 minutes. Next, a cyclohexane solution containing 38 parts by mass of butadiene, 1.9 parts by mass of styrene, and 37.1 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 50 minutes. Methanol was then added to terminate the polymerization reaction, and a conjugated diene copolymer was obtained. Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer to 100 parts by mass of the conjugated diene polymer (E3). The hydrogenation rate was 97%. The conjugated diene copolymer obtained as described above had 58.9% by mass of units (a-1), 3.1% by mass of units (a-2), and a number average molecular weight of 1.0×10 ４ The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 50%.

[0110] Production Example 4: Conjugated diene copolymer (E4) The same procedure as for the conjugated diene copolymer (E3) was carried out, and the hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the conjugated diene copolymer. A hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 0.75 hours to obtain conjugated diene copolymer (E4). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene polymer (E4). The conjugated diene copolymer obtained as described above had 58.9% by mass of units (a-1), 3.1% by mass of units (a-2), and a number average molecular weight of 1.0 × 10 ４The molecular weight distribution was 1.10, the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) was 50%, and the hydrogenation rate was 45%.

[0111] Production Example 5: Conjugated diene copolymer (E5) The same procedure as for the conjugated diene copolymer (E4) was carried out, except that the hydrogenation reaction time was changed to 1 hour. The conjugated diene copolymer obtained as described above had a content of 58.9% by mass of units (a-1), 3.1% by mass of units (a-2), and a number average molecular weight of 1.0 × 10 ４ The molecular weight distribution was 1.10, the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) was 50%, and the hydrogenation rate was 55%.

[0112] Production Example 6: Conjugated diene copolymer (E6) The same procedure as for the conjugated diene copolymer (E4) was carried out, except that the hydrogenation reaction time was changed to 1.5 hours. The conjugated diene copolymer obtained as described above had a content of 58.9% by mass of units (a-1), 3.1% by mass of units (a-2), and a number average molecular weight of 1.0 × 10 ４ The molecular weight distribution was 1.10, the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) was 50%, and the hydrogenation rate was 97%.

[0113] Production Example 7: Conjugated diene copolymer (E7) The same procedure as for the conjugated diene copolymer (E4) was carried out, except that the amount of n-butyllithium was 0.40 parts by mass relative to 100 parts by mass of the total monomers, and the hydrogenation reaction time was 1.5 hours. The conjugated diene copolymer obtained as described above had 58.9% by mass of units (a-1), 3.1% by mass of units (a-2), and a number average molecular weight of 2.0 × 10 ４ The molecular weight distribution was 1.10, the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) was 50%, and the hydrogenation rate was 97%.

[0114] <Production Example 8: Conjugated diene copolymer (E8)> Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 2.5 parts by mass of styrene, 47.5 parts by mass of p-methylstyrene, and 50 parts by mass of butadiene was added. Next, 0.80 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.3 mol of tetramethylethylenediamine (TMEDA) relative to 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 80 minutes. Methanol was then added to terminate the polymerization reaction, yielding a conjugated diene copolymer. The conjugated diene copolymer obtained as described above had 47.5% by mass of units (a-1), 2.5% by mass of units (a-2), and a number average molecular weight of 1.0 x 10 ４ The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 50%. The hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the conjugated diene copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain conjugated diene copolymer (E8). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene polymer (E8). The hydrogenation rate was 97%.

[0115] <Production Example 9: Conjugated Diene Copolymer (E9)> Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 1.6 parts by mass of styrene and 31.4 parts by mass of p-methylstyrene was added. Next, 0.92 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.6 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 25 minutes. Next, a cyclohexane solution containing 67 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 50 minutes. Thereafter, methanol was added to terminate the polymerization reaction, yielding a conjugated diene copolymer. The conjugated diene copolymer obtained as described above had 31.4% by mass of units (a-1), 1.6% by mass of units (a-2), and a number average molecular weight of 1.0 x 10 ４ The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 70%. The hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the conjugated diene copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain conjugated diene copolymer (E9). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene polymer (E9). The hydrogenation rate was 97%.

[0116] Production Example 10: Conjugated Diene Copolymer (E10) Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 1.0 part by mass of styrene and 19 parts by mass of p-methylstyrene was added. Next, 1.07 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.3 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 15 minutes. Next, a cyclohexane solution containing 80 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 60 minutes. Thereafter, methanol was added to terminate the polymerization reaction, yielding a conjugated diene copolymer. The conjugated diene copolymer obtained as described above had a composition of 19% by mass of units (a-1), 1.0% by mass of units (a-2), and a number average molecular weight of 1.0 x 10 ４ The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 50%. The hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the conjugated diene copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain a conjugated diene copolymer (E10). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene polymer (E10). The hydrogenation rate was 97%.

[0117] <Production Example 11: Conjugated Diene Copolymer (E11)> Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 0.6 parts by mass of styrene and 11.9 parts by mass of p-methylstyrene was added. Next, 1.07 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.3 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 15 minutes. Next, a cyclohexane solution containing 80 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 65 minutes. Thereafter, methanol was added to terminate the polymerization reaction, yielding a conjugated diene copolymer. The conjugated diene copolymer obtained as described above had a composition of 11.9% by mass of units (a-1), 0.6% by mass of units (a-2), and a number average molecular weight of 1.0 x 10 ４ The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 50%. The hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the block copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain a conjugated diene copolymer (E11). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene polymer (E11). The hydrogenation rate was 97%.

[0118] Comparative Production Example 12: Conjugated diene copolymer (E12) The same procedure as for the conjugated diene copolymer (E6) was carried out, except that all styrene was replaced with p-methylstyrene. The conjugated diene copolymer (E12) obtained as described above had 0% by mass of the unit (a-1), 100% by mass of the unit (a-2), and a number average molecular weight of 1.0 × 10 ４The molecular weight distribution was 1.10, the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) was 51%, and the hydrogenation rate was 97%. Note that, with regard to "polymer block (C)," as defined above in the section (Component (I): Conjugated diene copolymer and conjugated diene copolymer composition) as "representing a random polymer block (C) composed of vinyl aromatic monomer units and conjugated diene monomer units," (E12) was also expressed as having polymer block (C).

[0119] <Production Example 63-2: Conjugated diene copolymer (E13) for Example 63 described below> As described below, in the conjugated diene copolymer composition (X22) of Example 63-3, a conjugated diene copolymer (D23) and a conjugated diene copolymer (E13) were prepared in one reactor, and a conjugated diene copolymer composition (X22) composed of these was obtained. The hydrogenation rate of the conjugated diene copolymer (E13) was 97%.

[0120] <Production Example 64-2: Conjugated diene copolymer (E14) for Example 64 described below> As described below, in the conjugated diene copolymer composition (X23) of Example 64-3, the conjugated diene copolymer (D24) and the conjugated diene copolymer (E14) were prepared in one reactor, and the conjugated diene copolymer (X23) composed of these was obtained. The hydrogenation rate of the conjugated diene copolymer (E14) was 97%.

[0121] <Production Example 65-2: Conjugated diene copolymer (E15) for Example 65 described below> As described below, for the conjugated diene copolymer composition (X24) of Example 65-3, a conjugated diene copolymer (D25) and a conjugated diene copolymer (E15) were prepared in one reactor, and a conjugated diene copolymer (X24) composed of these was obtained. The hydrogenation rate of the conjugated diene copolymer (E15) was 97%.

[0122] Comparative Example 1: Conjugated diene copolymer (D16) The same procedure as for the conjugated diene copolymer (D8) was carried out, except that all p-methylstyrene was replaced with styrene. The conjugated diene copolymer obtained as above had 0.0% by mass of the unit (a-1), 35% by mass of the unit (a-2), and a number average molecular weight of 5.1 × 10 ４ The molecular weight distribution was 1.10, the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) was 50%, and the hydrogenation rate was 97%. Note that, with regard to "polymer block (C)," as defined above in the section (Component (I): Conjugated diene copolymer and conjugated diene copolymer composition) as "representing a random polymer block (C) composed of vinyl aromatic monomer units and conjugated diene monomer units," (D16) was also expressed as having polymer block (C).

[0123] Comparative Example 2: Conjugated diene copolymer (D17) The same procedure as for the conjugated diene copolymer (D8) was carried out, except that n-butyllithium was used in an amount of 0.0468 parts by mass relative to 100 parts by mass of the total monomers. The conjugated diene copolymer (D17) obtained as described above had a content of 33.3% by mass of units (a-1), 1.7% by mass of units (a-2), and a number-average molecular weight of 20×10 ４ The molecular weight distribution was 1.10, the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) was 50%, and the hydrogenation rate was 97%.

[0124] Comparative Example 3: Conjugated Diene Copolymer (D18) Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 2.0 parts by mass of styrene and 38 parts by mass of p-methylstyrene was added. Next, 0.32 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.35 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 40 minutes. Next, a cyclohexane solution containing 15 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 10 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 2.0 parts by mass of styrene and 38 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 40 minutes. Thereafter, methanol was added to terminate the polymerization reaction, and a conjugated diene copolymer was obtained. The conjugated diene copolymer obtained as described above had a content of 80.8% by mass of units (a-1), 4.2% by mass of units (a-2), and a number average molecular weight of 5.0 × 10 ４ The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 50%. The hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the conjugated diene copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain conjugated diene copolymer (D18). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene copolymer (D18). The hydrogenation rate was 97%.

[0125] Comparative Example 4: Conjugated Diene Copolymer (D19) Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 0.9 parts by mass of styrene and 16.6 parts by mass of p-methylstyrene was added. Next, 0.32 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.19 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 15 minutes. Next, a cyclohexane solution containing 65 parts by mass of butadiene was added, and polymerization was carried out at 60°C for 60 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 0.9 parts by mass of styrene and 16.6 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 15 minutes. Methanol was then added to terminate the polymerization reaction, and a conjugated diene copolymer was obtained. The conjugated diene copolymer obtained as described above had a content of 33.3% by mass of units (a-1), 1.7% by mass of units (a-2), and a number average molecular weight of 5.1 × 10 ４ The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 50%. The hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the conjugated diene copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain conjugated diene copolymer (D19). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene polymer (D19). The hydrogenation rate was 97%.

[0126] Comparative Example 5: Conjugated Diene Copolymer (D20) Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 0.4 parts by mass of styrene and 7.1 parts by mass of p-methylstyrene was added. Next, 0.32 parts by mass of n-butyllithium per 100 parts by mass of total monomers and 0.19 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 60°C for 10 minutes. Next, a cyclohexane solution containing 65 parts by mass of butadiene, 1 part by mass of styrene, and 19 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 65 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 0.4 parts by mass of styrene and 7.1 parts by mass of p-methylstyrene was added, and polymerization was carried out at 60°C for 10 minutes. Methanol was then added to terminate the polymerization reaction, and a conjugated diene copolymer was obtained. The conjugated diene copolymer obtained as described above had a content of 33.3% by mass of units (a-1), 1.7% by mass of units (a-2), and a number average molecular weight of 5.1 × 10 ４ The molecular weight distribution was 1.10, and the content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) was 50%. The hydrogenation catalyst prepared as described above was added to the resulting conjugated diene copolymer in an amount of 90 ppm (Ti) per 100 parts by mass of the conjugated diene copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain conjugated diene copolymer (D20). Next, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene polymer (D20). The hydrogenation rate was 97%.

[0127] Examples 17 to 32 and Comparative Examples 6 to 10 Conjugated diene copolymers (component (D) and component (E)) were mixed in the ratios shown in Tables 5 to 7 below to obtain conjugated diene copolymer compositions (component (X)).

[0128] Example 63-3: Conjugated Diene Copolymer Composition (X22) For the conjugated diene copolymer composition (X22), first, the conjugated diene copolymer (D23) and the conjugated diene copolymer (E13) were batch-polymerized using a single reactor, followed by a hydrogenation reaction to obtain a conjugated diene copolymer composition (X22) consisting of the conjugated diene copolymer (D23) and the conjugated diene copolymer (E13). Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 0.52 parts by mass of styrene and 9.98 parts by mass of p-methylstyrene was added. Next, 0.125 parts by mass of n-butyllithium per 100 parts by mass of the total monomers and 0.5 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 70°C for 10 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 42 parts by mass of butadiene was added and polymerized at 70 ° C. for 25 minutes. Next, 0.214 parts by mass of n-butyllithium (NBL2) per 100 parts by mass of total monomers and 0.4 mol of TMEDA per 1 mol of NBL2 were added, followed by the addition of a cyclohexane solution (concentration 25% by mass) containing 1.4 parts by mass of styrene and 27.1 parts by mass of p-methylstyrene, and polymerization was carried out at 70 ° C. for 20 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 9.5 parts by mass of butadiene, 0.02 parts by mass of styrene, and 9.03 parts by mass of p-methylstyrene was added and polymerized at 70 ° C. for 10 minutes. Methanol was then added to terminate the polymerization reaction, and a conjugated diene copolymer composition (X22) was obtained. The conjugated diene copolymer (D23) in the conjugated diene copolymer composition (X22) obtained as described above had a vinyl aromatic monomer unit content of 35% by mass in the conjugated diene copolymer (D23), a vinyl aromatic monomer content of 5% by mass in the random polymer block (C) in the conjugated diene copolymer (D23), a number average molecular weight of 51,000, a molecular weight distribution of 1.10, and a content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) of 51%.The conjugated diene copolymer (E13) in the conjugated diene copolymer composition (X22) obtained as described above had a vinyl aromatic monomer unit content of 72% by mass in the conjugated diene copolymer (E13), a vinyl aromatic monomer content of 5% by mass in the random polymer block (C) in the conjugated diene copolymer (E23), a number average molecular weight of 10,000, a molecular weight distribution of 1.10, and a content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) of 50%. The hydrogenation catalyst prepared as described above was added to the obtained conjugated diene copolymer composition (X22) in an amount of 90 ppm (Ti basis) per 100 parts by mass of the block copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain a solution of a hydrogenated block copolymer. The hydrogenation rate of the obtained conjugated diene copolymer composition (X22) was 97%. The mass ratio of the obtained conjugated diene copolymer (D23) to the conjugated diene copolymer (E13) was (D23) / (E13)=70 / 30.

[0129] Example 64-3: Conjugated Diene Copolymer Composition (X23) For the conjugated diene copolymer composition (X23), first, conjugated diene copolymer (D24) and conjugated diene copolymer (E14) were batch-polymerized using a single reactor, followed by a hydrogenation reaction to obtain a conjugated diene copolymer composition (X23) consisting of the conjugated diene copolymer (D24) and the conjugated diene copolymer (E14). Batch polymerization was carried out using a tank-type reactor (internal volume 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration 20% by mass) containing 0.3 parts by mass of styrene and 6.5 parts by mass of p-methylstyrene was added. Next, 0.048 parts by mass of n-butyllithium per 100 parts by mass of the total monomers and 0.5 mol of tetramethylethylenediamine (TMEDA) per 1 mole of n-butyllithium were added, and polymerization was carried out at 70°C for 7 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 2.3 parts by mass of butadiene, 2.2 parts by mass of styrene, and 0.1 parts by mass of p-methylstyrene was added, and polymerization was carried out at 70 ° C. for 5 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 11.3 parts by mass of butadiene was added, and polymerization was carried out at 70 ° C. for 10 minutes. Next, 0.117 parts by mass of n-butyllithium (NBL2) per 100 parts by mass of total monomers and 0.4 mol of TMEDA per 1 mol of NBL2 were added, followed by addition of a cyclohexane solution (concentration 25% by mass) containing 54.3 parts by mass of butadiene, and polymerization was carried out at 70 ° C. for 25 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 1.2 parts by mass of styrene and 22.1 parts by mass of p-methylstyrene was added, and polymerization was carried out at 70 ° C. for 15 minutes. Methanol was then added to terminate the polymerization reaction, and a conjugated diene copolymer composition (X23) was obtained. The conjugated diene copolymer (D24) in the conjugated diene copolymer composition (X23) obtained as described above had a vinyl aromatic monomer unit content of 35% by mass in the conjugated diene copolymer (D24), a vinyl aromatic monomer content of 5% by mass in the random polymer block (C) in the conjugated diene copolymer (D24), a number average molecular weight of 88,000, a molecular weight distribution of 1.10, and a content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) of 51%.The conjugated diene copolymer (E14) in the conjugated diene copolymer composition (X23) obtained as described above had a vinyl aromatic monomer unit content of 30% by mass, a number average molecular weight of 31,000, a molecular weight distribution of 1.10, and a content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) of 50%. The hydrogenation catalyst prepared as described above was added to the obtained conjugated diene copolymer composition (X23) in an amount of 90 ppm (Ti basis) per 100 parts by mass of the block copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 1.5 hours to obtain a solution of a hydrogenated block copolymer. The hydrogenation rate of the obtained conjugated diene copolymer composition (X23) was 97%. The mass ratio of the obtained conjugated diene copolymer (D24) to the conjugated diene copolymer (E14) was (D24) / (E14)=45 / 55.

[0130] Example 65-3 Conjugated diene copolymer composition (X24) A conjugated diene copolymer (X24) consisting of a conjugated diene copolymer (D25) and a conjugated diene copolymer (E15) was produced by the same procedure as for the conjugated diene copolymer composition (X23), except that NBL2 was used at 0.88 parts by mass. The conjugated diene copolymer (D25) in the conjugated diene copolymer composition (X23) obtained as described above had a vinyl aromatic monomer unit content of 35% by mass in the conjugated diene copolymer (D25), a vinyl aromatic monomer content of 5% by mass in the random polymer block (C) in the conjugated diene copolymer (D25), a number average molecular weight of 88,000, a molecular weight distribution of 1.10, and a content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content) of 51%. The conjugated diene copolymer (E15) in the conjugated diene copolymer composition (X24) obtained as described above had a vinyl aromatic monomer unit content of 30% by mass, a number average molecular weight of 6,000, a molecular weight distribution of 1.10, a content of units derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount) of 50%, a hydrogenation rate of 97%, and a mass ratio of the conjugated diene copolymer (D25) to the conjugated diene copolymer (E15) of (D25) / (E15) = 45 / 55.

[0131] (Component (II): Radical initiator) Perbutyl P (manufactured by NOF Corporation)

[0132] (Component (III): Curable Resin) Polyphenylene ether (PPE) resin: OPE-2St 1200 (manufactured by Mitsubishi Gas Chemical Company, Inc.)

[0133] (Component (IV): Flame retardant) SAYTEX 8010 (manufactured by ALBEMARLE)

[0134] (Component (V): Filler) Silica: SOC2 (manufactured by Admatechs Co., Ltd.)

[0135] [Resin Compositions and Cured Products] <Examples 33 to 65>, <Comparative Examples 11 to 22> Resin compositions and cured products were prepared using the component (I): conjugated diene copolymer, conjugated diene copolymer composition, and the components (II) to (V) of the above examples and comparative examples.

[0136] [Preparation of Varnish] Using the conjugated diene copolymers and conjugated diene copolymer compositions of the Examples, Production Examples, and Comparative Examples, varnishes containing resin compositions were prepared by measuring out each component into a container, dissolving it in toluene (manufactured by Wako Pure Chemical Industries, Ltd.), and stirring it according to the formulations shown in Tables 8 to 11. At this time, the concentration of the resin composition in the varnish was adjusted to 40 to 60 mass%.

[0137] [Preparation of Prepreg Using Varnish and Cured Prepreg] A varnish of a resin composition prepared according to the formulation shown in the table below was impregnated into a glass substrate (L2116, #2116 type, "L Glass", manufactured by Asahi Kasei Corporation), followed by heating and drying at 130°C for 50 minutes to obtain a prepreg (PP (1)). Six sheets of the obtained prepreg (1) were stacked, heated to 200°C at a heating rate of 2°C / min, and heated and pressed at 200°C for 2 hours under a pressure of 3 MPa to obtain a cured prepreg (cured substrate (1)) with a dielectric constant, dielectric tangent, and a thickness of 0.7 mm. Two sheets of PP (1) were stacked between two copper foils, heated to 200°C at a heating rate of 2°C / min, and heated and pressed at 200°C for 60 minutes under a pressure of 1.1 MPa to obtain a sample for measuring copper adhesion (cured substrate (2)).

[0138] [Method for measuring physical properties of resin composition] ((1) Dielectric loss tangent and dielectric constant) The dielectric loss tangent at 10 GHz of the obtained cured substrate (1) was measured by a cavity resonance method. A network analyzer (N5230A, manufactured by Agilent Technologies) and a cavity resonator (Cavity Resonator CP series) manufactured by Kanto Electronics Application Development Co., Ltd. were used as measuring devices. Measurement samples were measured using test pieces measuring 2.6 mm wide x 80 mm long cut out from the prepreg described in the preparation method above. The Dk and Df obtained in the above measurements were evaluated on a six-point scale according to the following criteria. The higher the value, the better the dielectric loss tangent and dielectric constant. Dk 5: Dielectric constant is less than 3.0. 4: Dielectric constant is less than 3.1 and 3.0 or more. 3: Dielectric constant is less than 3.3 and 3.1 or more. 2: Dielectric constant is less than 3.4 and 3.3 or more. 1: The dielectric constant is less than 3.5 and equal to or greater than 3.4. 0: The dielectric constant is equal to or greater than 3.5. Df 5: The dielectric dissipation factor is less than 0.0015. 4: The dielectric dissipation factor is less than 0.0019 and equal to or greater than 0.0015. 3: The dielectric dissipation factor is less than 0.0022 and equal to or greater than 0.0019. 2: The dielectric dissipation factor is less than 0.0025 and equal to or greater than 0.0022. 1: The dielectric dissipation factor is less than 0.0027 and equal to or greater than 0.0025. 0: The dielectric dissipation factor is equal to or greater than 0.0027.

[0139] (2) Glass Transition Temperature (Tg) The dynamic viscoelasticity of the cured substrate (1) was measured, and the temperature at which tan δ reached a maximum was determined as the glass transition temperature (Tg). An ARES (trade name, manufactured by TA Instruments Japan) was used as the measuring device, and the cured prepreg described above was cut into a length of 40 mm, a width of approximately 10 mm, and a thickness of 0.7 mm for use as a measurement sample. Measurement was performed in torsion mode at a frequency of 10 rad / s and a measurement temperature of -150 to 270°C. The Tg obtained in the above measurement was evaluated on a six-point scale according to the following criteria. The higher the value, the higher the Tg and the more excellent the heat resistance. 5: The glass transition temperature was 200°C or higher. 4: The glass transition temperature was 190°C or higher but less than 200°C. 3: The glass transition temperature was 170°C or higher but less than 190°C. 2: The glass transition temperature was 150°C or higher but less than 170°C. 1: The glass transition temperature is 140° C. or higher and lower than 150° C. 0: The glass transition temperature is lower than 140° C.

[0140] (3) Adhesion to Copper Foil) The copper adhesion strength of the cured substrate (2) was evaluated using a tension and compression tester TGE manufactured by NebeaMitsumi Inc. The adhesion strength obtained in the above measurement was evaluated on a 6-point scale according to the following criteria. A higher value indicates better adhesion to copper foil. 5: Copper peel strength is 0.8 N / mm or more. 4: Copper peel strength is 0.6 N / mm or more and less than 0.8 N / mm. 3: Copper peel strength is 0.3 N / mm or more and less than 0.6 N / mm. 2: Copper peel strength is 0.2 N / mm or more and less than 0.3 N / mm. 1: Copper peel strength is 0.1 N / mm or more and less than 0.2 N / mm. 0: Copper peel strength is less than 0.1 N / mm.

[0141] (4) Minimum Viscosity During Curing) The melt viscosity of the PP (1) produced in the Examples and Comparative Examples was measured using a dynamic viscoelasticity measuring device (TA Instruments Japan, "ARES-G2"). This measurement was performed using parallel plates with a diameter of 8 mm, with six sheets of PP (1) stacked on top of each other. The measurement conditions were a starting temperature of 50°C to 250°C, a temperature rise rate of 5°C / min, a measurement temperature interval of 2.5°C, and an oscillation frequency of 1 Hz / deg. The minimum value of the obtained complex viscosity was taken as the minimum viscosity during curing. The adhesive strength obtained in the above measurement was evaluated on a four-point scale according to the following criteria. The smaller the value, the lower the viscosity. 4: 50,000 Pa·s or less 3: 60,000 Pa·s or less 2: 300,000 Pa·s or less 1: 1,000,000 Pa·s or less 0: More than 1,000,000 Pa·s

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[0149]

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[0152]

[0153] It was revealed that the examples had low dielectric constants and low dielectric loss tangents, and also had excellent heat resistance and adhesion to metal foils, demonstrating that the present invention is suitable for use in glass cloth using the cured product and printed wiring boards using metal laminates.

[0154] This application is based on a Japanese patent application (Patent Application No. 2024-032298) filed with the Japan Patent Office on March 4, 2024, the contents of which are incorporated herein by reference.

[0155] The conjugated diene copolymer of the present invention, a resin composition containing the conjugated diene copolymer, and a cured product thereof have industrial applicability as materials for films, prepregs, electronic circuit boards, and next-generation communication boards.

Claims

1. A conjugated diene copolymer satisfying the following conditions (1) to (3): (Condition (1)) The conjugated diene copolymer comprises a polymer block (A) containing a vinyl aromatic monomer unit (a-1) having a radical reactive group, a polymer block (B) mainly composed of a conjugated diene monomer unit (b), and a random polymer block (C) containing the vinyl aromatic monomer unit (a-1) having a radical reactive group and the conjugated diene monomer unit (b), and mainly composed of the vinyl aromatic monomer unit (a) containing the unit (a-1) and the conjugated diene monomer unit (b). (Condition (2)) The number-average molecular weight of the conjugated diene copolymer is more than 40,000 but not more than 150,000. (Condition (3)) The content of all vinyl aromatic monomer units (a) including the unit (a-1) in the conjugated diene copolymer is 5 to 70 mass%.

2. The conjugated diene copolymer according to claim 1, further satisfying the following condition (4): (Condition (4)) The number average molecular weight of the conjugated diene copolymer is more than 40,000 and not more than 100,000.

3. The conjugated diene copolymer according to claim 1, wherein the polymer block (A) further comprises a vinyl aromatic monomer unit (unit (a-2)) (excluding unit (a-1)), the polymer block (A) is mainly composed of the vinyl aromatic monomer unit (a-1) having a radical reactive group and the vinyl aromatic monomer unit (a-2), the total content of the unit (a-1) and the unit (a-2) in the conjugated diene copolymer is 5 to 70 mass%, and the random polymer block (C) further comprises a vinyl aromatic monomer unit (unit (a-2)) (excluding unit (a-1)), and the random polymer block (C) is mainly composed of the unit (a-1), the unit (a-2), and the conjugated diene monomer unit (b).

4. The conjugated diene copolymer according to claim 1, wherein the conjugated diene monomer unit (b) is an acyclic conjugated diene monomer unit.

5. The conjugated diene copolymer according to claim 1, wherein at least a portion of the conjugated diene monomer units of said conjugated diene copolymer is hydrogenated.

6. The conjugated diene copolymer according to claim 3, further satisfying the following condition (5): (Condition (5)) The mass ratio of the units (a-1) to the units (a-2) is (a-1) / (a-2)=30 / 70 to 99 / 1.

7. The conjugated diene copolymer according to claim 1, wherein at least a portion of the conjugated diene monomer units of said conjugated diene copolymer is hydrogenated, with a hydrogenation rate of 98% or less.

8. The conjugated diene copolymer according to claim 1, wherein at least a portion of the conjugated diene monomer units of said conjugated diene copolymer is hydrogenated, and the hydrogenation rate is 50% or more and 98% or less.

9. The conjugated diene copolymer according to claim 1, wherein the conjugated diene copolymer has three or more ends.

10. The conjugated diene copolymer according to claim 1, wherein the conjugated diene copolymer has five or more ends.

11. A conjugated diene copolymer composition comprising the conjugated diene copolymer (conjugated diene copolymer (D)) according to claim 1 and a conjugated diene copolymer (E) satisfying the following (conditions (6)) to (conditions (7)): (condition (6)) The number average molecular weight is 40,000 or less. (condition (7)) The conjugated diene copolymer composition has at least one polymer block selected from the group consisting of polymer block (A) containing vinyl aromatic monomer units (a-1) having a radical reactive group, random polymer block (C) containing the units (a-1) and conjugated diene monomer units (b) and consisting mainly of the vinyl aromatic monomer units (a) containing the units (a-1) and the conjugated diene monomer units (b), and polymer block (B) consisting mainly of conjugated diene monomer units, and has the polymer block (A) and / or the random polymer block (C).

12. The conjugated diene copolymer composition according to claim 11, wherein the polymer block (A) constituting the conjugated diene copolymer (E) further comprises a vinyl aromatic monomer unit (unit (a-2)) (excluding unit (a-1)), the polymer block (A) constituting the conjugated diene copolymer (E) is mainly composed of the total of the vinyl aromatic monomer unit (a-1) having a radical reactive group and the vinyl aromatic monomer unit (a-2), and the random polymer block (C) constituting the conjugated diene copolymer (E) further comprises a vinyl aromatic monomer unit (unit (a-2)) (excluding unit (a-1)).

13. The conjugated diene copolymer composition according to claim 11, wherein the conjugated diene copolymer (E) further satisfies the following condition (8): (Condition (8)) The ratio (MnD / MnE) of the number average molecular weight (MnD) of the conjugated diene copolymer (D) to the number average molecular weight (MnE) of the conjugated diene copolymer (E) is greater than 2.

14. A resin composition comprising: component (I): the conjugated diene copolymer according to any one of claims 1 to 10, or the conjugated diene copolymer composition according to any one of claims 11 to 13; and at least one component selected from the group consisting of the following components (II) to (III): component (II): a radical initiator; and component (III): a curable resin (excluding component (I)).

15. The resin composition according to claim 14, wherein component (III) is a radical curable resin having at least one reactive group selected from the group consisting of a vinyl group, a maleimide group, an allyl group, and a methacryl group.

16. A cured product of the conjugated diene copolymer according to any one of claims 1 to 10.

17. A cured product of the conjugated diene copolymer composition according to any one of claims 11 to 13.

18. A cured product of the resin composition according to claim 14.

19. A resin film made from the resin composition according to claim 14.

20. A prepreg, which is a composite of a substrate and the resin composition according to claim 14.

21. The prepreg according to claim 20, wherein the substrate is glass cloth.

22. A laminate comprising the resin film according to claim 19 and a metal foil.

23. A material for electronic circuit boards, comprising the cured product according to claim 18.

24. A material for electronic circuit boards, comprising the resin film according to claim 19.

25. A material for an electronic circuit board, comprising the prepreg of claim 20.