Resin composition, cured product, resin film, prepreg, laminate, and material for electronic circuit board

Abstract

To provide a resin composition that has a low dielectric constant and a low dielectric loss tangent, by which a cured product having low melt viscosity in curing is obtained, furthermore which has excellent varnish stability, adhesiveness with a metal foil, and blocking resistance of pellets.SOLUTION: A resin composition contains: a component (I): a conjugated diene-based copolymer which contains a vinyl aromatic monomer unit and a conjugated diene monomer unit and satisfies specific conditions (i) to (iv); a component (II): radical initiator; a component (III): at least one selected from the group consisting of epoxy-based resin, maleimide-based resin, polyphenylene ether-based resin, liquid crystal polyester-based resin, and fluorine-based resin (provided that the component (I) is excluded), and a component (IV): at least one component selected from the group consisting of curing agents (provided that the component (II) is excluded).SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] 2. Description of the Related Art In recent years, with the remarkable progress in information network technology and the expansion of services utilizing information networks, electronic devices are required to handle larger amounts of information and to process faster. To meet these demands, materials with low dielectric loss are required for various substrates such as printed circuit boards and flexible substrates.

[0003] Conventionally, in order to obtain a material with small dielectric loss, various resin materials have been studied and disclosed, such as thermosetting resins such as epoxy resins, which have low dielectric constants and / or low dielectric dissipation factors and excellent mechanical properties such as strength, and cured resins containing thermoplastic resins such as polyphenylene ether resins as their main components. However, the resin materials disclosed so far still have room for improvement in terms of low dielectric constant and low dielectric loss tangent, and when these materials are used in printed circuit boards, there is a problem that the amount of information and processing speed are limited.

[0004] To overcome these problems, various rubber components have been proposed as modifiers for the above-mentioned thermosetting resins and thermoplastic resins. For example, Patent Document 1 discloses a reactive styrene copolymer and its hydrogenated product as a modifier for improving the tensile properties and the like of polyphenylene ether resin. Furthermore, Patent Document 2 discloses a styrene-based elastomer as a modifier for imparting flexibility and adhesiveness to a polyphenylene ether resin. Furthermore, Patent Document 3 discloses a styrene-based elastomer as a modifier for lowering the dielectric loss tangent and dielectric constant of an epoxy resin. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2021 / 065964 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-1473 [Patent Document 3] Japanese Patent Publication No. 2020-15861 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the resin compositions using the modifiers disclosed in Patent Documents 1, 2, and 3 still do not have sufficiently low dielectric constants and low dielectric loss tangents, and the addition of the modifiers tends to reduce fluidity during curing.

[0007] Therefore, an object of the present invention is to provide a resin composition which has a low dielectric constant and a low dielectric dissipation factor, gives a cured product with a low melt viscosity upon curing, and further has excellent varnish stability, adhesion to metal foil, and pellet blocking resistance. [Means for solving the problem]

[0008] As a result of intensive research conducted by the present inventors to solve the problems of the conventional art described above, they found that a resin composition having a specific configuration has a low dielectric constant and a low dielectric dissipation factor, and gives a cured product with a low melt viscosity upon curing, and further has excellent varnish stability, adhesion to metal foil, and pellet blocking resistance, and thus completed the present invention. That is, the present invention is as follows.

[0009] [1] Component (I): A conjugated diene copolymer comprising vinyl aromatic monomer units and conjugated diene monomer units, Conjugated diamines that satisfy the following conditions (i), (ii), (iii), and (iv) an ene-based copolymer; and at least one component selected from the group consisting of the following components (II) to (IV): Resin composition. <Condition (i)> (a) It contains at least one polymer block mainly composed of vinyl aromatic monomer units, and the content of the (a) polymer block mainly composed of vinyl aromatic monomer units is 10% by mass or more and 40% by mass or less. <Condition (ii)> (b) At least one copolymer block consisting of a vinyl aromatic monomer unit and a conjugated diene monomer unit is contained, and the content of the vinyl aromatic monomer unit in the copolymer block (b) is 30% by mass or more and 79% by mass or less. <Condition (iii)> The instantaneous hardness measured with a durometer type A according to JIS K6253 is 60 or more, and the instantaneous hardness measured with a durometer type D is 65 or less. <Condition (iv)> The MFR value measured in accordance with JIS K7210 at a temperature of 230°C and a load of 2.16 kg is 10 (g / 10 min) or more. Component (II): Radical initiator Component (III): At least one resin selected from the group consisting of epoxy resins, maleimide resins, polyphenylene ether resins, liquid crystal polyester resins, and fluorine-based resins (excluding component (I)). Component (IV): Curing agent (excluding component (II)) [2] The instantaneous hardness measured with a durometer type A according to JIS K6253 is 85 or more, and the instantaneous hardness measured with a durometer type D is 45 or less. The resin composition according to [1]. [3] The conjugated diene copolymer has an MFR value of 15 (g / 10 min) or more, measured in accordance with JIS K7210 at a temperature of 230°C and a load of 2.16 kg. The resin composition according to [1] or [2]. [4] the conjugated diene copolymer further contains (c) at least one polymer block mainly composed of conjugated diene monomer units, the content of the polymer block (c) mainly composed of conjugated diene monomer units is 3% by mass or more; The resin composition according to any one of [1] to [3]. [5] the conjugated diene copolymer further contains (c) at least one polymer block mainly composed of conjugated diene monomer units, the total of the vinyl bond content in the (b) copolymer block and the vinyl bond content in the (c) polymer block mainly composed of conjugated diene monomer units is 30% by mass or more; The resin composition according to any one of [1] to [4]. [6] the conjugated diene copolymer further contains (c) at least one polymer block mainly composed of conjugated diene monomer units, the content of the polymer block (c) mainly composed of conjugated diene monomer units is 3% by mass or more and 20% by mass or less; The resin composition according to any one of [1] to [5]. [7] Contains the component (III), The resin composition according to any one of [1] to [6], wherein the component (III) includes an epoxy resin. [8] Contains the component (III), The resin composition according to any one of [1] to [7], wherein the component (III) contains a maleimide resin. [9] A cured product of the resin composition according to any one of [1] to [8].

[10] A resin film comprising the resin composition according to any one of [1] to [8].

[11] A substrate; The resin composition according to any one of [1] to [8], Prepreg is a composite material.

[12] The substrate is a glass cloth. The prepreg according to

[11] .

[13] A laminate comprising the resin film according to

[10] and a metal foil.

[14] A cured product of the prepreg according to

[11] , a metal foil, A laminate having:

[15] A material for electronic circuit boards, comprising the cured product according to [9]. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a resin composition which gives a cured product having a low dielectric constant and a low dielectric dissipation factor and a low melt viscosity upon curing, and which further has excellent varnish stability, adhesion to metal foil, and pellet blocking resistance. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. It should be noted that the following embodiments are merely examples for explaining the present invention, and are not intended to limit the present invention to the following content. The present invention can be implemented in various modified forms within the scope of its gist.

[0012] [Resin composition] The resin composition of the present embodiment is Component (I): 1. A block copolymer comprising vinyl aromatic monomer units and conjugated diene monomer units, Conjugated diamines that satisfy the following conditions (i), (ii), (iii), and (iv) an ene-based copolymer; and at least one component selected from the group consisting of the following components (II) to (IV): It is a resin composition. <Condition (i)> The composition contains at least one (a) polymer block mainly composed of vinyl aromatic monomer units (hereinafter also referred to as "polymer block (a)"), and the content of the (a) polymer block mainly composed of vinyl aromatic monomer units is 10% by mass or more and 40% by mass or less. <Condition (ii)> (b) The copolymer contains at least one copolymer block (hereinafter also referred to as "copolymer block (b)") consisting of a vinyl aromatic monomer unit and a conjugated diene monomer unit, and the content of the vinyl aromatic monomer unit in the copolymer block (b) is 30% by mass or more and 79% by mass or less. <Condition (iii)> The instantaneous hardness measured with a durometer type A according to JIS K6253 is 60 or more, and the instantaneous hardness measured with a durometer type D is 65 or less. <Condition (iv)> The MFR value measured in accordance with JIS K7210 at a temperature of 230°C and a load of 2.16 kg is 10 or more. Component (II): Radical initiator Component (III): At least one resin selected from the group consisting of epoxy resins, maleimide resins, polyphenylene ether resins, liquid crystal polyester resins, and fluorine-based resins (excluding component (I)). Component (IV): Curing agent (excluding component (II))

[0013] By configuring the resin composition of the present embodiment in this manner, a cured product having a low dielectric constant and a low dielectric loss tangent and a low melt viscosity upon curing can be obtained, and further the resin composition has excellent varnish stability, adhesion to metal foil, and pellet blocking resistance.

[0014] The resin composition of the present embodiment contains a conjugated diene-based copolymer that is a block copolymer containing vinyl aromatic monomer units and conjugated diene monomer units and satisfies the above conditions (i) to (iv).

[0015] In the present embodiment, the conjugated diene monomer unit refers to a structural unit derived from a conjugated diene compound in a polymer formed by polymerization of a conjugated diene compound. In the present embodiment, the conjugated diene compound is a diolefin having a pair of conjugated double bonds. 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, and 1,3-cyclohexadiene. Among these, 1,3-butadiene and isoprene are preferred, and 1,3-butadiene is more preferred. 1,3-Butadiene and isoprene are widely used and easily available, are advantageous from the viewpoint of cost, and can easily be copolymerized with styrene, which is widely used as a vinyl aromatic compound, as described below. These may be used alone or in combination of two or more. The conjugated diene compound may be a biotechnological compound.

[0016] In the present embodiment, the vinyl aromatic monomer unit refers to a structural unit derived from a vinyl aromatic compound in a polymer formed by polymerization of a vinyl aromatic compound. Examples of vinyl aromatic compounds include, but are not limited to, styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 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.

[0017] <Condition (i)> The conjugated diene copolymer used in the resin composition of this embodiment contains at least one (a) polymer block mainly composed of vinyl aromatic monomer units, and the content of the (a) polymer block mainly composed of vinyl aromatic monomer units is 10% by mass or more and 40% by mass or less.

[0018] In the present embodiment, the term "mainly composed of" means that the proportion of the monomer in a given block polymer or polymer block is 85% by mass or more, preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably no other monomer is intentionally added. The content of the vinyl aromatic monomer units in the copolymer block (b) is 30% by mass or more and 79% by mass or less, so that the polymer block (a) and the copolymer block (b) can be clearly distinguished. Among the monomer units constituting the conjugated diene copolymer, the vinyl aromatic monomer units tend to have higher compatibility with components (II), (III), and (IV) than the conjugated diene monomer units, and from the viewpoint of varnish stability, the content of the polymer block (a) is preferably 10% by mass or more. Furthermore, in terms of preventing pellet blocking, the conjugated diene copolymer used in the resin composition of this embodiment preferably has a polymer block (a) content of 15% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more. If the pellets of the conjugated diene copolymer used in the resin composition of this embodiment exhibit good blocking resistance, blocking tends to be less likely to occur even under conditions such as longer transportation times, higher loads, and severe temperature environments (for example, areas with high outside temperatures or large temperature differences). Furthermore, since the amount of anti-blocking agent can be reduced, effects such as avoiding equipment contamination, reducing environmental load, and suppressing unexpected deterioration of physical properties, such as suppressing a decrease in transparency, can be expected.

[0019] Among the monomer units constituting the conjugated diene copolymer, the conjugated diene monomer unit has higher radical reactivity than the vinyl aromatic monomer unit with a radical initiator and / or at high temperatures in the curing step of the resin composition described below. Therefore, from the viewpoint of the balance between the compatibility and reactivity, the content of the polymer block (a) is preferably 40% by mass or less, more preferably 37% by mass or less, and even more preferably 35% by mass or less.

[0020] The content of each monomer unit constituting the conjugated diene copolymer used in the resin composition 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 of this embodiment as a sample. The content of polymer block (a) can be controlled within the above range mainly by adjusting the amount of vinyl aromatic compound added to the polymerization reactor, the reaction temperature and the reaction time.

[0021] <Condition (ii)> The conjugated diene copolymer used in the resin composition of this embodiment contains at least one copolymer block (b) consisting of a vinyl aromatic monomer unit and a conjugated diene monomer unit, and the content of the vinyl aromatic monomer unit in the copolymer block (b) is 30% by mass or more and 79% by mass or less.

[0022] When focusing on the solubility parameter, vinyl aromatic monomer units tend to have higher compatibility with components (II) to (IV) described below compared to conjugated diene monomer units. In order to improve the compatibility between the ene copolymer and the components (II) to (IV), the amount of the vinyl aromatic monomer in the polymer block (b) is preferably 30% by mass or more. Generally, printed circuit boards are laminates of metal foils such as copper foils and resin compositions, but with the demand for improved dielectric performance mentioned above, i.e., demands for lower dielectric loss tangents and lower dielectric constants, the use of smooth metal foils is required from the viewpoint of reducing conductor loss. However, smooth metal foils have a small anchoring effect and therefore have low adhesion to resin compositions, so there is a demand for resin compositions that have excellent adhesion to smooth copper foils. From the viewpoint of the adhesiveness described above, the conjugated diene copolymer used in the resin composition of this embodiment preferably has high polarity within a range that does not impair the dielectric performance described above. From the viewpoint of solubility parameter, it is known that vinyl aromatic monomer units have higher polarity than conjugated diene monomer units. From the viewpoint described above, by including a copolymer block (b) having vinyl aromatic monomer units and conjugated diene monomer units, the polarity of the entire polymer chain increases, which tends to improve adhesion to metal foils such as copper foils. From the viewpoint of improving adhesiveness as described above, the content of copolymer block (b) is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, even more preferably 35% by mass or more, and particularly preferably 40% by mass or more. The content of vinyl aromatic monomer units in the copolymer block (b) is 30% by mass or more, preferably 40% by mass or more, and more preferably 45% by mass or more.

[0023] The conjugated diene monomer units in the copolymer block (b) tend to exhibit reactivity with the components (II) to (IV) and reactivity between the conjugated diene copolymers themselves. However, from the viewpoint of compatibility and balance, the amount of the vinyl aromatic monomer in the polymer block (b) is preferably 79% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less.

[0024] The content of the vinyl aromatic monomer unit in the copolymer block (b) can be measured by a nuclear magnetic resonance (NMR) spectrometer or the like. The content of the vinyl aromatic monomer unit in the copolymer block (b) can be controlled within the above-mentioned range by adjusting the amounts of the vinyl aromatic compound and conjugated diene added to the polymerization reactor, the reaction temperature, etc.

[0025] Although a conjugated diene copolymer consisting only of copolymer block (b) is considered to have the compatibility and reactivity described above, the compatibility tends to be lower than that of polymer block (a) due to the copolymerization of conjugated diene monomer units. Furthermore, the reactivity of the conjugated diene monomer units tends to be lower due to the steric hindrance of the vinyl aromatic monomer. Therefore, from the viewpoint of the balance between compatibility and reactivity, the conjugated diene copolymer used in the resin composition of this embodiment contains (a) at least one polymer block mainly composed of vinyl aromatic monomer units, and (b) at least one copolymer block composed of vinyl aromatic monomer units and conjugated diene monomer units.

[0026] As will be described later, when the resin composition of the present embodiment is subjected to a curing reaction, for example, at high temperature, the molecular chains of the conjugated diene copolymer undergo a radical reaction with each other and / or with component (II): a radical initiator, component (III): at least one selected from the group consisting of an epoxy resin, a maleimide resin, a polyphenylene ether resin, a liquid crystal polyester resin, and a fluorine-based resin, and component (IV): a curing agent, which will be described later, and / or are compatible with each other, which tends to improve the stability of the varnish of the resin composition. Furthermore, the above-mentioned radical reaction suppresses the decrease in polymer mobility and / or polarization due to an external electric field in the resin composition and cured product of this embodiment, and the resin composition and cured product tend to have a low dielectric loss tangent and / or a low dielectric constant. Furthermore, since the conjugated diene copolymer has a low dielectric constant and / or a low dielectric loss tangent, the resin composition and cured product described below tend to have a low dielectric loss tangent and / or a low dielectric constant.

[0027] Components (II), (III), and (IV), described below, have polar groups. Focusing on the solubility parameter, among the monomer units constituting the conjugated diene copolymer, vinyl aromatic monomer units tend to be more compatible with components (II), (III), and (IV) than conjugated diene monomer units. On the other hand, conjugated diene monomer units exhibit radical reactivity with a radical initiator and / or at high temperatures during the curing process of the resin composition described below, which tends to reduce the polarity of the conjugated diene copolymer and improve the dielectric performance of the resin composition of this embodiment. Since the dielectric performance of the cured resin composition can also be controlled by the dielectric performance of the conjugated diene copolymer, the structure of the conjugated diene copolymer is preferably designed from the perspectives of solubility parameter, radical reactivity, and achieving a low dielectric constant and / or low dielectric loss tangent of the conjugated diene copolymer.

[0028] <Condition (iii)> The conjugated diene copolymer used in the resin composition of this embodiment has an instantaneous hardness of 60 or more as measured with a durometer type A according to JIS K6253, and an instantaneous hardness of 65 or less as measured with a durometer type D.

[0029] The conjugated diene copolymer used in the resin composition of this embodiment preferably has an instantaneous hardness of 65 or less, more preferably 55 or less, and even more preferably 45 or less, as measured with a durometer type D according to JIS K6253.

[0030] The conjugated diene copolymer used in the resin composition of this embodiment preferably has an instantaneous hardness of 60 or more, more preferably 75 or more, and even more preferably 85 or more, as measured with a durometer type A according to JIS K6253.

[0031] When the conjugated diene copolymer used in the resin composition of this embodiment has an instantaneous hardness of 60 or more as measured with a durometer type A according to JIS K6253 and an instantaneous hardness of 65 or less as measured with a durometer type D, pellets of the conjugated diene copolymer used in the resin composition of this embodiment tend to exhibit good blocking resistance. High blocking resistance in conjugated diene copolymer pellets means that blocking is less likely to occur during transportation for longer periods of time, under higher loads, and in harsh temperature environments, such as in regions with high outside temperatures or large temperature differences, which is expected to facilitate pellet measurement and blending during compound molding. Furthermore, the amount of anti-blocking agent added can be reduced, which can prevent equipment contamination, reduce environmental impact, and is expected to suppress unexpected deterioration in physical properties, such as a decrease in transparency.

[0032] The hardness of the conjugated diene copolymer can be controlled within the above-mentioned range by adjusting the weight-average molecular weight of the conjugated diene copolymer, the content of polymer block (a), the content of vinyl aromatic monomer units in copolymer block (b), the amount of vinyl bonds in the conjugated diene monomer units, and the hydrogenation rate of double bonds in the conjugated diene monomer units.

[0033] <Condition (iv)> The conjugated diene copolymer used in the resin composition of this embodiment has an MFR value of 10 (g / 10 min) or more, measured according to JIS K7210 at a temperature of 230° C. and a load of 2.16 kg.

[0034] When the MFR of the conjugated diene copolymer used in the resin composition of this embodiment is 10 (g / 10 min) or more, a conjugated diene copolymer with a low melt viscosity is obtained, and the resin composition of this embodiment and the cured product of the resin composition tend to have a low melt viscosity when cured. From the above viewpoint, the MFR of the conjugated diene copolymer used in the resin composition of the present embodiment is preferably 15 (g / 10 min) or more, more preferably 25 (g / 10 min) or more, even more preferably 35 (g / 10 min) or more, even more preferably 45 (g / 10 min) or more, and still more preferably 55 (g / 10 min) or more. The low melt viscosity results in good wiring embedding properties when used in printed wiring boards. From the viewpoint of blocking properties, the MFR of the conjugated diene copolymer used in the resin composition of the present embodiment is preferably 1000 (g / 10 min) or less, more preferably 800 (g / 10 min) or less, and even more preferably 600 (g / 10 min) or less.

[0035] The MFR of the conjugated diene copolymer can be controlled within the above-mentioned range by adjusting the weight-average molecular weight of the conjugated diene copolymer, the content of polymer block (a), the content of vinyl aromatic monomer units in copolymer block (b), the amount of vinyl bonds in the conjugated diene monomer units, and the hydrogenation rate of double bonds in the conjugated diene monomer units. For example, the MFR of the conjugated diene copolymer tends to be improved by reducing the weight-average molecular weight of the conjugated diene copolymer, reducing the content of polymer block (a), increasing the content of vinyl aromatic monomer units in copolymer block (b), increasing the amount of vinyl bonds in the conjugated diene monomer units, and reducing the hydrogenation rate of double bonds in the conjugated diene monomer units. In particular, the weight-average molecular weight of a conjugated diene copolymer has a linear relationship with the logarithm of MFR. Therefore, to obtain a conjugated diene copolymer that exhibits the effects of the present invention, for example, the content of polymer block (a) and the content of vinyl aromatic monomer units in copolymer block (b) may be adjusted so as to impart compatibility and / or reactivity within a range that does not impair dielectric performance, and then the weight-average molecular weight that gives the desired MFR may be determined from the linear relationship between the weight-average molecular weight of the conjugated diene copolymer and the logarithm of MFR.

[0036] The conjugated diene copolymer used in the resin composition of this embodiment preferably further contains at least one (c) polymer block mainly composed of conjugated diene monomer units (hereinafter also referred to as "polymer block (c)"), and the content of the (c) polymer block mainly composed of conjugated diene monomer units is preferably 3 mass% or more.

[0037] The content of the polymer block mainly composed of (c) conjugated diene monomer units is preferably 3% by mass or more because the polymer block has higher radical reactivity than the vinyl aromatic monomer units at high temperatures in the curing step of the resin composition described below with a radical initiator. Furthermore, increasing the content of polymer block (c) in the terminal blocks tends to improve the MFR. The conjugated diene monomer units tend to exhibit reactivity with the components (II) to (IV) and reactivity between the conjugated diene copolymers themselves. From the viewpoint of achieving a good compatibility balance, the amount of the vinyl aromatic monomer in the polymer block (c) is preferably 20% by mass or less, more preferably 18% by mass or less.

[0038] <Vinyl bond content> The conjugated diene copolymer used in the resin composition of the present embodiment preferably contains, in the conjugated diene copolymer before hydrogenation, conjugated diene monomer units that include units derived from 1,2-bonds and / or 3,4-bonds and units derived from 1,4-bonds. When the total content of conjugated diene monomer units in the conjugated diene copolymer before hydrogenation is taken as 100%, the sum of the vinyl bond amount in the (b) copolymer block and the vinyl bond amount in the (c) polymer block mainly composed of conjugated diene monomer units is preferably 30% or more, more preferably 35% or more, and even more preferably 40% or more, from the viewpoint of the reactivity of the conjugated diene monomer units described above. When the vinyl bond content is high, the radical reactivity of the conjugated diene copolymer tends to be high, regardless of the hydrogenation rate. The vinyl bond content can be controlled within the above-mentioned range by using a regulator such as a polar compound in the polymerization process of the conjugated diene copolymer, and can be calculated by the method described in the examples below.

[0039] The adjuster is not particularly limited, but examples thereof include tertiary amine compounds and ether compounds, with the use of tertiary amine compounds being preferred. The tertiary amine compound is a compound of 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 tertiary amine compounds 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.

[0040] The conjugated diene copolymer used in the resin composition of the present embodiment may have a copolymer block (d) obtained by copolymerizing a compound other than the polymer blocks (a), (b), and (c) with a conjugated diene compound and / or a vinyl aromatic compound, within a range that does not impair dielectric performance, in order to increase the polarity of the conjugated diene copolymer to a level that can be imparted by controlling the content of the polymer block (a) mainly composed of vinyl aromatic monomer units and / or the vinyl bond amount in the copolymer block (b) and / or the content of the polymer block (c) mainly composed of conjugated diene monomer units, and to impart compatibility and / or reactivity with components (II), (III), and (IV) described below. For example, when a conjugated diene copolymer containing copolymer block (d) is produced by anionic polymerization, methyl methacrylate (MMA) can be copolymerized with a vinyl aromatic compound or a conjugated diene compound and can be used as a compound constituting copolymer block (d). By including MMA, the dielectric constant and / or dielectric loss tangent of the conjugated diene copolymer tend to deteriorate, but the polarity of the conjugated diene copolymer increases, and the compatibility and / or reactivity described above tend to improve.

[0041] The content of the vinyl aromatic monomer unit in the conjugated diene copolymer used in the resin composition of the present embodiment can be measured by the method described in the examples below. The content of the vinyl aromatic monomer units can be controlled within the above-mentioned range by adjusting the amount of monomer added in the polymerization step and the polymerization time.

[0042] In the conjugated diene copolymer of the present embodiment, the unsaturated bond derived from the conjugated diene monomer unit may be hydrogenated. The hydrogenation method is not particularly limited, and known methods can be applied. The hydrogenation rate affects the reactivity and compatibility of component (I) with components (II) to (IV).

[0043] In the hydrogenation reaction, a known hydrogenation catalyst can be used. The hydrogenation catalyst is not particularly limited, but examples thereof include: (1) supported heterogeneous hydrogenation catalysts in which a metal such as Ni, Pt, Pd, or Ru is supported on carbon, silica, alumina, diatomaceous earth, or the like; (2) so-called Ziegler-type hydrogenation catalysts which use a transition metal salt such as an organic acid salt or acetylacetonate salt of Ni, Co, Fe, Cr, or the like and a reducing agent such as organoaluminum; and (3) homogeneous hydrogenation catalysts such as so-called organometallic complexes of organometallic compounds such as Ti, Ru, Rh, Zr, or the like. The hydrogenation catalyst is not particularly limited, but for example, the hydrogenation catalysts described in JP-B-42-8704, JP-B-43-6636, JP-B-63-4841, JP-B-1-37970, JP-B-1-53851, and JP-B-2-9041 can be used. Preferred hydrogenation catalysts include titanocene compounds and / or reducing organometallic compounds.

[0044] The titanocene compound is not particularly limited, but for example, the compounds described in JP-A-8-109219 can be used. Examples of the titanocene compound 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 biscyclopentadienyltitanium dichloride and monopentamethylcyclopentadienyltitanium trichloride. The titanocene compound may contain one of the above skeletons alone, or two of them in combination.

[0045] 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 may be used alone or in combination of two or more.

[0046] The hydrogenation rate of the conjugated diene copolymer used in the resin composition of this embodiment can be controlled by appropriately adjusting the reaction temperature, reaction time, hydrogen supply amount, catalyst amount, etc. in the hydrogenation method. The hydrogenation reaction is preferably carried out at a temperature of 55 to 200°C, more preferably 60 to 170°C, and even more preferably 65 to 160°C. The hydrogen pressure 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 by a batch process, a continuous process, or a combination thereof.

[0047] (Method of producing conjugated diene copolymer) The conjugated diene copolymer used in the resin composition of the present embodiment is not particularly limited, but can be produced, for example, by performing living anionic polymerization in a hydrocarbon solvent using a polymerization initiator such as an organic alkali metal compound, followed by a hydrogenation reaction.

[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.

[0049] The polymerization initiator is not particularly limited, but examples thereof include 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. The organic alkali metal compound is not particularly limited, but examples thereof include aliphatic and aromatic hydrocarbon lithium compounds having 1 to 20 carbon atoms, including compounds containing one lithium atom per molecule, dilithium compounds containing multiple lithium atoms per molecule, trilithium compounds, and tetralithium compounds.

[0050] Specific 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 isoprene monomer molecules have been inserted to improve solubility, siloxy-containing alkyllithiums such as 1-(t-butyldimethylsiloxy)hexyllithium, as disclosed in British Patent No. 2,241,239, amino-containing alkyllithiums such as diisopropylamidelithium and hexamethyldisilazidelithium, as disclosed in U.S. Patent No. 5,527,753, can also be used.

[0051] As a method for polymerizing a vinyl aromatic compound and a conjugated diene compound using an organic alkali metal compound as a polymerization initiator, a conventionally known method can be applied. The polymerization method is not particularly limited, and may be, for example, batch polymerization, continuous polymerization, or a combination thereof. In particular, batch polymerization is suitable for obtaining a uniform polymer. The polymerization temperature is preferably from 0°C to 180°C, more preferably from 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. The polymerization atmosphere is preferably an inert gas atmosphere such as nitrogen gas. The polymerization pressure is not particularly limited, as long as it is set within a pressure range that allows the monomer and solvent to be maintained in a liquid phase within the above-mentioned temperature range. Furthermore, care must be taken to prevent the introduction of impurities that may inactivate the catalyst and living polymer, such as water, oxygen, carbon dioxide, etc., into the polymerization system.

[0052] Furthermore, at the end of the polymerization step, a required amount of a bifunctional or higher functional coupling agent may be added to carry out a coupling reaction, but because coupling agents generally contain polar groups, if a large amount of coupling agent is added, any unreacted coupling agent may remain, which tends to cause ion migration. From the viewpoint of suppressing ion migration, the coupling rate is preferably 40% or less, more preferably 30% or less, even more preferably 20% or less, and even more preferably no coupling agent is contained.

[0053] The bifunctional coupling agent is not particularly limited and may be any known one. 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 phthalates.

[0054] Furthermore, as the trifunctional or higher polyfunctional coupling agent, any known agent can be used, and there is no particular limitation. The tri- or higher functional polyfunctional coupling agent is not particularly limited, but examples thereof include trivalent or higher polyalcohols, epoxidized soybean oil, polyhydric epoxy compounds such as diglycidyl bisphenol A and 1,3-bis(N-N'-diglycidylaminomethyl)cyclohexane; 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 bromides thereof; 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, polyvalent halogen compounds such as methyltin trichloride, t-butyltin trichloride, and tin tetrachloride. Dimethyl carbonate, diethyl carbonate, etc. may also be used.

[0055] The hydrogenation reaction of the conjugated diene copolymer can be carried out by a known method using a known hydrogenation catalyst, as described above.

[0056] Compounds containing metal atoms in polymerization initiators used in producing conjugated diene copolymers by anionic living polymerization and in hydrogenation catalysts used in hydrogenation reactions tend to react with moisture in the air during desolvation steps, etc., to generate specific metal compounds that remain in the conjugated diene copolymer. Reducing the amount of catalyst residue in the conjugated diene copolymer reduces the amount of metal compounds contained in the cured product, which tends to improve insulation reliability and suppress ion migration. The remaining metal compound is not particularly limited, and examples thereof include compounds of metals contained in the polymerization initiator and the hydrogenation catalyst, oxides of each atom 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 each atom with a different metal such as lithium titanate, barium titanate, strontium titanate, nickel titanate, and nickel-iron oxide.

[0057] For the purpose of improving insulation reliability and / or preventing ion migration, the amount of metal compounds remaining in the conjugated diene copolymer used in the resin composition of this embodiment is preferably 150 ppm or less, more preferably 130 ppm or less, even more preferably 100 ppm or less, and still more preferably 90 ppm or less, in terms of the amount of residual metal. Specific examples of residual metals include Ti, Ni, Li, Co, etc.

[0058] Methods for reducing the amount of residual metal in a conjugated diene copolymer can be any known method, and are not particularly limited. For example, a method of adding water and carbon dioxide gas after the hydrogenation reaction of a conjugated diene copolymer to neutralize the hydrogenation catalyst residue, or a method of adding water, carbon dioxide gas, and an acid to neutralize the hydrogenation catalyst residue, can be used. Specifically, the method described in Japanese Patent Application No. 2014-557427 can be used. Even when these metal removal methods are used, water containing hydroxides of metal compounds is mixed in during the desolvation process of the conjugated diene copolymer, and therefore, the amount of metal typically remains at about 1 to 15 ppm. Therefore, it is preferable to remove at least 20% of the amount of metal added to the conjugated diene copolymer, more preferably at least 30%, even more preferably at least 40%, even more preferably at least 50%, and even more preferably at least 60%.

[0059] Furthermore, although it is possible to reduce the amount of residual metal in the conjugated diene copolymer used in the resin composition of this embodiment by reducing the amounts of polymerization initiator and hydrogenation catalyst added, reducing the amount of polymerization initiator increases the molecular weight of the conjugated diene copolymer, which tends to lead to a deterioration in the solvent solubility of the resin composition described below and a deterioration in handleability due to an increase in the viscosity of the resin composition solution. Furthermore, when performing a hydrogenation reaction, reducing the amount of hydrogenation catalyst tends to lengthen the hydrogenation reaction time and increase the hydrogenation reaction temperature, resulting in a significant decrease in productivity.

[0060] The method for separating the solvent when recovering the conjugated diene copolymer is not particularly limited, and examples thereof 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 copolymer solution is directly heated to distill off the solvent.

[0061] The conjugated diene copolymer may contain various stabilizers such as phenol-based stabilizers, phosphorus-based stabilizers, sulfur-based stabilizers, and amine-based stabilizers. In the process for producing the conjugated diene copolymer used in the resin composition of this embodiment, a step of forming a "polar group" may be carried out to the extent that the dielectric properties are not impaired.

[0062] Examples of polar groups include, but are not limited to, atomic groups containing at least one functional group selected from the group consisting of 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 alkoxytin group, and a phenyltin group.

[0063] The polar group can be formed by reacting a modifier with the conjugated diene copolymer. 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.

[0064] The method for forming the polar group is not particularly limited and any known method can be applied. For example, there may be mentioned a melt-kneading method, or a method in which the components are dissolved or dispersed in a solvent or the like and mixed to react with each other. In addition to the method using the above-mentioned modifying agent, a method of polymerization using a polymerization initiator having a functional group or an unsaturated monomer having a functional group by anionic living polymerization can also be applied. Further, although not particularly limited, examples of the modification include a method of performing an addition reaction of a modifier that forms or contains a functional group at the living end, and a method of reacting a copolymer with an organic alkali metal compound such as an organic lithium compound (metallation reaction), and then performing an addition reaction of a modifier having a functional group on the polymer to which the organic alkali metal compound has been added.

[0065] (Components Constituting Resin Composition) As described above, the resin composition of the present embodiment contains the conjugated diene copolymer (component (I)) and at least one component selected from the group consisting of the following components (II) to (IV): Component (II): Radical initiator Component (III): At least one resin selected from the group consisting of epoxy resins, maleimide resins, polyphenylene ether resins, liquid crystal polyester resins, and fluorine-based resins (excluding component (I)). Component (IV): Hardener (excluding component (II)) From the viewpoint of reducing the dielectric constant, the dielectric loss tangent, and the flexibility of the resin composition of this embodiment and the cured product thereof, it is preferable that the resin composition of this embodiment contains component (I): a conjugated diene copolymer and component (II): a radical initiator.

[0066] (Component (II): Radical initiator) The radical initiator may be any known one and is not particularly limited, but examples thereof include thermal radical initiators. Examples of thermal radical initiators 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-2,5-bis(t-butylperoxy)hexane (Perhexa 25B), t-butylcumyl peroxide (Perbutyl C), di-t-butyl peroxide (Perbutyl D), and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane (Perhexa 25B). Examples of the peroxide include dialkyl peroxides such as 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), organic peroxides such as diacyl peroxides, peroxydicarbonates, and 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 may be used alone or in combination of two or more.

[0067] (Component (III): at least one selected from the group consisting of epoxy resins, maleimide resins, polyphenylene ether resins, liquid crystal polyester resins, and fluorine-based resins) From the viewpoint of imparting performance such as adhesion to a predetermined substrate to the extent that the dielectric performance of the cured product is not impaired, the resin composition of this embodiment preferably contains component (III): at least one selected from the group consisting of epoxy-based resins, maleimide-based resins, polyphenylene ether-based resins, liquid crystal polyester-based resins, and fluorine-based resins (excluding component (I)). By containing at least one selected from the group consisting of epoxy-based resins, maleimide-based resins, polyphenylene ether-based resins, liquid crystal polyester-based resins, and fluorine-based resins, the resin composition of this embodiment tends to have excellent dielectric performance. When component (III) is a polar resin having radical reactivity, the amount of the radical initiator of component (II) described above can be adjusted appropriately depending on the reactivity, or component (II) can be omitted.

[0068] Examples of the radically reactive polar resin as component (III) include a homopolymer of a compound containing at least one vinyl group and / or a halogen element in the polymer, and a copolymer of the compound containing the vinyl group and / or a halogen element with any other compound. From the viewpoint of the dielectric performance of the resin composition of this embodiment, the polar resin is preferably a polymer having a vinyl group.

[0069] (Component (IV): Curing agent) When the radical reactivity of the above-mentioned component (III) is low, from the viewpoint of reactivity, it is preferable that the resin composition of the present embodiment contains component (IV): a curing agent (excluding component (II)). Component (IV) curing agent generally has the function of reacting with component (III): at least one resin selected from the group consisting of epoxy resins, maleimide resins, polyphenylene ether resins, liquid crystal polyester resins, and fluorine-based resins, to cure the resin composition. The "reaction" of component (III) and component (IV) means that the polar groups of each component have covalent bonding properties. When polar groups react with each other, for example, when the OH of a carboxyl group is eliminated, the original polar group changes or disappears. If this results in the formation of a covalent bond, this is included in the definition of the polar groups being "reactive." From the viewpoint of curing function, it is preferable that component (IV) has at least two polar groups in one molecular chain that can react with the functional group of component (III). The component (IV) may be used alone or in combination of two or more.

[0070] The type of polar group contained in component (III) and component (IV) is not particularly limited, but examples thereof include: Epoxy groups, carboxy groups, carbonyl groups, ester groups, imidazole groups, hydroxyl groups, amino groups, mercaptan groups, benzoxazine groups, carbodiimide groups, phenolic hydroxyl groups; a combination of an amino group and any group selected from the group consisting of a carboxyl group, a carbonyl group, a hydroxyl group, an acid anhydride group, a sulfonic acid group, and an aldehyde group; a combination of an isocyanate group and any one selected from the group consisting of a hydroxyl group, a carboxylic acid, and a phenolic hydroxyl group; A combination of an acid anhydride group and a hydroxy group; a combination of a silanol group and any group selected from the group consisting of a hydroxy group and a carboxylic acid group; a combination of a halogen group and any group selected from the group consisting of a carboxylic acid group, a carboxylic acid ester group, an amino group, a phenol group, and a thiol group; a combination of an alkoxy group and any group selected from the group consisting of a hydroxy group, an alkoxide group, and an amino group; A combination of a maleimide group and a cyanate group; etc. Whether the bond of these polar groups is component (III) or component (IV) can be selected arbitrarily.

[0071] In addition, cases where the polar group of component (III) and the polar group of component (IV) do not react directly but can react by adding a curing accelerator such as a catalyst are also included in the definition of "reactive." For example, when component (III) is a polar resin having epoxy groups and component (IV) is a curing agent having acid anhydride groups, the reactivity between epoxy groups and acid anhydride groups is usually very low, but by adding a compound having amino groups as a curing accelerator, the epoxy groups and amino groups in component (III) react, and some or all of the epoxy groups in component (III) become hydroxyl groups. The resin composition is cured by the reaction of these hydroxyl groups with the acid anhydride groups of the curing agent of component (IV).

[0072] From the viewpoint of reactivity, the ratio of the amounts of component (III) and component (IV) is preferably such that the molar ratio of polar groups of component (III):polar groups of component (IV) is 1:0.01 to 1:20, more preferably 1:0.05 to 1:15, and even more preferably 1:0.1 to 1:10.

[0073] Component (IV): Curing agent. Examples of curing agents having an ester group include, but are not limited to, EXB9451, EXB9460, EXB, 9460S, HPC8000-65T, HPC8000H-65TM, EXB8000L-65TM, EXB8150-65T, and EXB9416-70BK manufactured by DIC Corporation, and YLH1026, DC808, YLH1026, YLH1030, and YLH1048 manufactured by Mitsubishi Chemical Corporation.

[0074] Examples of curing agents having a hydroxyl group include, but are not limited to, MEH-7700, MEH-7810, MEH-7851, NHN, CBN, and GPH manufactured by Nippon Kayaku Co., Ltd., SN170, SN180, SN190, SN475, SN485, SN495, SN-495V, and SN375 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., and TD-2090, LA-7052, LA-7054, LA-1356, LA-3018-50P, and EXB-9500 manufactured by DIC Corporation.

[0075] Examples of curing agents having a benzoxazine group include, but are not limited to, ODA-BOZ manufactured by JFE Chemical Corporation, HFB2006M manufactured by Showa Polymer Co., Ltd., and Pd and Fa manufactured by Shikoku Chemicals Corporation.

[0076] Examples of curing agents having an isocyanate group include, but are not limited to, bifunctional cyanate resins such as bisphenol A dicyanate, polyphenol cyanate, oligo(3-methylene-1,5-phenylene cyanate), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl)thioether, and bis(4-cyanatephenyl)ether; polyfunctional cyanate resins derived from phenol novolac and cresol novolac; and prepolymers in which these cyanate resins are partially converted to triazine. Commercially available products include PT30, PT60, ULL-950S, BA230, and BA230S75 manufactured by Lonza Japan.

[0077] Examples of curing agents having a carbodiimide group include, but are not limited to, V-03 and V-07 manufactured by Nisshinbo Chemical Inc.

[0078] Examples of the curing agent having an amino group include, but are not limited to, 4,4'-methylenebis(2,6-dimethylaniline), diphenyldiaminosulfone, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-amino Examples of the bis(4-aminophenyl)propane include 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, and bis(4-(3-aminophenoxy)phenyl)sulfone. Commercially available products include KAYABOND C-200S, KAYABOND C-100, KAYAHARD AA, KAYAHARD AB, and KAYAHARD AS manufactured by Nippon Kayaku Co., Ltd., and Epicure W manufactured by Mitsubishi Chemical Corporation.

[0079] From the viewpoint of reactivity, the amino group is preferably a primary amine and / or a secondary amine, more preferably a primary amine.

[0080] Examples of curing agents having an acid anhydride group include, but are not limited to, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenone. Examples of suitable anhydrides include tetracarboxylic dianhydrides, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bis(anhydrotrimellitate), and polymeric anhydrides such as styrene-maleic acid resin, which is a copolymer of styrene and maleic acid.

[0081] Furthermore, compounds having at least two of the aforementioned radically reactive structures also have the function of reacting with component (III) to cure the resin composition, and such compounds can also be used as curing agents for component (IV). Examples of compounds having at least two radically reactive structures include, but are not limited to, allyl monomers such as triallyl isocyanurate (Taikyu, manufactured by Mitsubishi Chemical Corporation), tris(2-hydroxyethyl) isocyanurate, diallyl fumarate, diallyl adipate, triallyl citrate, and diallyl hexahydrophthalate.

[0082] (Preferred material for component (III)) When the resin composition of the present embodiment contains component (III), from the viewpoint of dielectric performance, it is preferably at least one selected from the group consisting of epoxy-based resins, maleimide-based resins, polyphenylene ether-based resins, liquid crystal polyester-based resins, and fluorine-based resins. Furthermore, when the resin composition of the present embodiment contains component (III), from the viewpoint of heat resistance, component (III) is more preferably at least one selected from the group consisting of epoxy resins and maleimide resins.

[0083] The epoxy resin as component (III) may be any resin that falls into the category of epoxy resins, and from the viewpoint of strength, it preferably has two or more epoxy groups in one molecule. The epoxy resins may be used alone or in combination of two or more. Examples of epoxy resins include, but are not limited to, bixylenol-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, bisphenol AF-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol novolac-type epoxy resins, phenol novolac-type epoxy resins, tert-butyl-catechol-type epoxy resins, naphthalene-type epoxy resins, naphthol-type epoxy resins, anthracene-type epoxy resins, glycidylamine-type epoxy resins, glycidyl ester-type epoxy resins, cresol novolac-type epoxy resins, biphenyl-type epoxy resins, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexane-type epoxy resins, cyclohexanedimethanol-type epoxy resins, naphthylene ether-type epoxy resins, trimethylol-type epoxy resins, and tetraphenylethane-type epoxy resins.

[0084] Furthermore, when an epoxy resin is used as component (III) from the viewpoint of reactivity, it is preferable to also contain component (IV) curing agent. In this case, examples of the polar group possessed by component (IV) curing agent include a carboxy group, an imidazole group, a hydroxyl group, an amino group, a mercaptan group, a benzoxazine group, and a carbodiimide group. From the viewpoint of reactivity, a carboxy group, an imidazole group, a hydroxyl group, a benzoxazine group, and a carbodiimide group are preferred. From the viewpoint of the dielectric performance of the resin composition of this embodiment, a hydroxyl group, a carboxy group, an imidazole group, a benzoxazine group, and a carbodiimide group are more preferred, and a hydroxyl group, a carboxy group, and a carbodiimide group are even more preferred.

[0085] The maleimide resin as component (III) may be any resin that falls into the category known as maleimide resins. The maleimide resin may be used alone or in combination of two or more. Examples of maleimide resins include, but are not limited to, 4,4'-diphenylmethane bismaleimide, phenylmethane maleimide, m-phenylene bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, and 1,6'-bismaleimide-(2,2,4-trimethyl)hexane.

[0086] Specific examples of the maleimide resin, which is component (III), preferably used in this embodiment include, but are not limited to, MIR-3000-70MT (manufactured by Nippon Kayaku Co., Ltd.), BMI-1000 (manufactured by Daiwa Chemical Industry Co., Ltd.), and BMI-3000 (manufactured by Daiwa Chemical Industry Co., Ltd.).

[0087] The polyphenylene ether resin (hereinafter also referred to as "PPE resin") which is component (III) may be any resin that belongs to the category called polyphenylene ether resin. Examples of PPE resins include, but are not limited to, SA90 and SA9000 manufactured by SHPP Japan LLC, and OPE-2St-1200 and OPE-2St-2200 manufactured by Mitsubishi Gas Chemical Company, Inc.

[0088] Furthermore, when two or more polar resins with different radical reactivity are used as component (III), it is preferable to use a combination of component (II): a radical initiator and component (IV): a curing agent from the viewpoint of curability. For example, when a maleimide resin with excellent radical reactivity and a bisphenol A epoxy resin with no radical reactivity are used as component (III), it is preferable to add the above-mentioned component (II) radical initiator and the above-mentioned component (IV) curing agent from the viewpoint of curability.

[0089] (Contents of Components (I) to (IV)) The resin composition of this embodiment contains a conjugated diene polymer (component (I)) and at least one component selected from the group consisting of the above-mentioned components (II) to (IV). The content is preferably in the following numerical range when the component (I) is taken as 100 parts by mass. Component (II): 0.01 to 200 parts by mass is preferred, more preferably 0.05 to 150 parts by mass, and even more preferably 0.10 to 100 parts by mass. Component (III): 5 to 2000 parts by mass is preferred, more preferably 10 to 1000 parts by mass, and even more preferably 30 to 800 parts by mass. Component (IV): 5 to 2000 parts by mass is preferred, more preferably 10 to 1000 parts by mass, and even more preferably 30 to 500 parts by mass.

[0090] The resin composition in this embodiment may be a mixture of the components melted and kneaded together, or may be a mixture of the components dissolved in a solvent in which they can be dissolved and stirred (hereinafter referred to as "varnish"), but varnish is preferred from the viewpoint of ease of handling. The solvent constituting the varnish is not particularly limited, but examples thereof include 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 monoacetate; 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 organic solvents may be used alone or in combination of two or more.

[0091] (Method of producing resin composition) The method for producing the resin composition of the present embodiment is not particularly limited, and known methods can be used. Examples of such methods include a method in which the components are melt-kneaded 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, and a method in which the components are dissolved or dispersed and mixed, and then the solvent is removed by heating.From the viewpoint of processability into molded articles suitable for use as materials for electronic circuit boards, such as prepregs and sheets, which will be described later, the method in which the components are dissolved or dispersed and mixed, and then the solvent is removed by heating is preferred.

[0092] [Cured product] The cured product of this embodiment is a cured product of the resin composition of this embodiment described above, and contains the conjugated diene copolymer, which is the component (I) described above. The cured product of this embodiment can be obtained by subjecting the resin composition of this embodiment to a curing reaction at any temperature for any period of time. This concept encompasses not only a completely cured product, but also a partially cured product in which only a portion of the resin composition is cured and contains uncured components (semi-cured product). 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, it is preferable to carry out the curing reaction after removing the solvent. 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. Drying is carried out so that the amount of solvent in the resin composition is preferably 10% by mass or less, more preferably 5% by mass or less.

[0093] [Resin film] The resin film of the present embodiment contains the resin composition of the present embodiment described above. The resin film of the present embodiment is not particularly limited, but can be obtained, for example, by spreading a varnish made of the resin composition of the present embodiment onto a predetermined support to form a uniform thin film, drying the varnish, and removing the solvent. Such a resin film can be wound into a roll and stored. The resin film of this embodiment may be configured with a predetermined protective film laminated thereon, and in such a case, the resin film can be used by peeling off the protective film.

[0094] [Prepreg] The prepreg of the present embodiment includes a substrate and the resin composition of the present embodiment impregnated into or coated on the substrate. That is, the prepreg of the present embodiment is a composite of the resin composition of the present embodiment and the substrate. The prepreg is not particularly limited, but can be obtained, for example, by impregnating a substrate such as glass cloth with the varnish that is the resin composition of the present embodiment described above, and then removing the solvent by the drying method described above. The substrate is not particularly limited, but examples thereof 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 blended fiber yarn; and polytetrafluoroethylene porous film. From the viewpoint of dielectric performance, glass cloth is preferred. These substrates may be used singly 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 of solids made up of the resin composition is 80% by mass or less, the prepreg tends to have better mechanical properties such as rigidity when used for electronic substrates, etc.

[0095] [Laminate] The laminate of this embodiment includes the resin film and metal foil described above. Alternatively, the laminate of this embodiment may include a cured product of the prepreg described above and metal foil. The laminate of the present embodiment can be produced, for example, through a step (A) of laminating a resin film made of the resin composition of the present embodiment onto a substrate to form a resin layer and obtain a prepreg, a step (B) of flattening the resin layer by heating and pressurizing it to obtain a cured prepreg, and a step (C) of further forming a predetermined wiring layer made of a metal foil on the resin layer.

[0096] In step (A), the method for laminating the resin film onto the substrate is not particularly limited, but examples thereof include lamination methods using a multi-stage press, a vacuum press, an atmospheric pressure laminator, or a laminator that heats and presses under vacuum, and a method using a laminator that heats and presses under vacuum is preferred. In the method using this laminator, even if the target electronic circuit board has a fine wiring circuit on the surface, the spaces between the circuits can be filled with resin without leaving 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, a glass epoxy substrate, a metal substrate, a polyester substrate, a maleimide substrate, a polyphenylene ether substrate, a fluororesin substrate, etc. The surface of the substrate on which the resin layer is to be laminated may be roughened in advance, and the number of substrate layers is not limited.

[0097] In the step (B), the resin film and the substrate laminated in the step (A) are heated and pressurized to be flattened. The conditions can be adjusted as desired depending on the type of substrate and the composition of the resin film, but preferred ranges are, for example, a temperature of 100 to 300°C, a pressure of 0.2 to 20 MPa, and a time of 30 to 180 minutes.

[0098] In the step (C), a predetermined wiring layer made of a metal foil is further formed on the resin layer produced by heating and pressing the resin film and the substrate. The formation method is not particularly limited, and includes conventionally known methods, such as subtractive etching methods and semi-additive methods. The subtractive method is a method of forming the desired wiring by forming an etching resist layer on a metal layer in a shape corresponding to the desired pattern shape, and then performing a development process to dissolve and remove the metal layer in the areas where the resist has been removed with a chemical solution. The semi-additive method is a method in which a metal coating is formed on the surface of a resin layer by electroless plating, a plating resist layer of a shape corresponding to the desired pattern is formed on the metal coating, a metal layer is then formed by electrolytic plating, and the unnecessary electroless plating layer is then removed with a chemical solution or the like to form the desired wiring layer.

[0099] Furthermore, holes such as via holes may be formed in the resin layer as needed, and the method for forming the holes is not particularly limited and any conventionally known method can be used, such as an NC drill, a carbon dioxide laser, a UV laser, a YAG laser, or plasma.

[0100] [Metal-clad laminate] The laminate of the present embodiment described above may be in the form of a plate or may be a flexible laminate having flexibility. The laminate of this embodiment may be a metal-clad laminate. The metal-clad laminate is obtained by laminating the resin composition of the present embodiment or the prepreg of the present embodiment and a metal foil, followed by curing, and a part of the metal foil is removed. The metal-clad laminate preferably has a configuration in which a cured prepreg (also referred to as a "cured composite") and a metal foil are laminated and adhered together, and is suitably used as a material for electronic circuit boards. The metal foil is not particularly limited, but examples thereof include aluminum foil and copper foil, and among these, copper foil is preferred because of its low electrical resistance. The cured prepreg to be combined with the metal foil may be one or more sheets, and depending on the application, the metal foil is laminated on one or both sides of the cured product to form a metal-clad laminate. Examples of methods for producing the metal-clad laminate include a method in which a prepreg composed of the resin composition of the present embodiment and a substrate is formed, this is layered on a metal foil, and the resin composition is then cured to obtain a metal-clad laminate in which the cured prepreg and the metal foil are laminated together. One particularly preferred application of the metal-clad laminate is a printed wiring board, which is preferably a metal-clad laminate from which at least a portion of the metal foil has been removed. The printed wiring board can be produced by a pressure and heat molding method using the prepreg of the present embodiment described above. The same substrate as that described above for the prepreg can be used as the base material. By including the resin composition of the present embodiment, the printed wiring board has excellent strength and electrical properties (low dielectric constant and low dielectric loss tangent), and can also suppress fluctuations in electrical properties due to environmental changes, resulting in excellent insulation reliability and mechanical properties.

[0101] [Materials for electronic circuit boards] The material for the electronic circuit board of this embodiment includes a cured product of the resin composition of this embodiment described above. The material for an 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 boards of this embodiment preferably contains 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 a cured product thereof, and a prepreg which is a composite of a substrate and a resin composition. The material for electronic circuit boards of this embodiment can be used as a printed wiring board having a resin-coated metal foil. [Example]

[0102] 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.

[0103] The methods for identifying the structure and measuring the physical properties of the hydrogenated conjugated diene copolymer or unhydrogenated conjugated diene copolymer (component (I)) (hereinafter sometimes referred to as conjugated diene copolymer) in the following Examples and Comparative Examples are shown below.

[0104] [Methods for identifying the structure of conjugated diene copolymers and measuring their physical properties] ((1) Content of vinyl aromatic monomer units in conjugated diene copolymer) Before hydrogenation, the conjugated diene copolymer was used and the content of vinyl aromatic monomer units in the copolymer was measured using an ultraviolet spectrophotometer (Shimadzu Corporation, UV-2450).

[0105] ((2) Content of polymer block mainly composed of vinyl aromatic monomer unit in conjugated diene copolymer) The content of polymer blocks mainly composed of vinyl aromatic monomer units was measured using a nuclear magnetic resonance (NMR) spectrometer for the conjugated diene copolymer before hydrogenation according to the method described in Y. Tanaka, et al., RUBBER CHEMISTRY and TECHNOLOGY 54, 685 (1981) (hereinafter referred to as the "NMR method").

[0106] ((3) Content of vinyl aromatic monomer units in copolymer block (b)) Using the conjugated diene copolymer before hydrogenation as a sample, a nuclear magnetic resonance (NMR) spectrometer was used to measure the total vinyl aromatic monomer unit content in the conjugated diene copolymer by the above-mentioned NMR method. From the difference between the content of all vinyl aromatic monomer units in the conjugated diene copolymer and the content of polymer block (a) mainly composed of vinyl aromatic monomer units in the conjugated diene copolymer, the vinyl aromatic monomer unit content in copolymer block (b) relative to the entire polymer was calculated, and the vinyl aromatic monomer unit content in copolymer block (b) was calculated from the ratio of the vinyl aromatic monomer content to the conjugated diene monomer content in copolymer block (b).

[0107] ((4) Vinyl Bond Amount of Conjugated Diene Copolymer) The conjugated diene copolymer before hydrogenation was used to measure the vinyl bond amount using an infrared spectrophotometer (manufactured by JASCO Corporation, FT / IR-230). The vinyl bond content of the conjugated diene copolymer was calculated by the Hampton method.

[0108] ((5) Molecular Weight and Molecular Weight Distribution of Conjugated Diene Copolymers) The molecular weight of the conjugated diene copolymer (I) before modification and hydrogenation was measured by GPC (apparatus: LC-10 (Shimadzu Corporation), column: TSKgel GMHXL (4.6 mm x 30 cm)). The solvent used was tetrahydrofuran. The measurement was carried out at a temperature of 35°C. The molecular weight is a weight average molecular weight 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) determined from the measurement of commercially available standard polystyrene. When there are multiple peaks in the chromatogram, the molecular weight is the average molecular weight calculated from the molecular weight of each peak and the composition ratio of each peak (calculated from the area ratio of each peak in the chromatogram).

[0109] ((6) Hydrogenation rate of double bonds of conjugated diene monomer units of conjugated diene copolymer) Using the component (I) after hydrogenation: a conjugated diene copolymer, the hydrogenation rate of the double bonds of the conjugated diene monomer units was measured using a nuclear magnetic resonance spectrometer (manufactured by BRUKER, DPX-400).

[0110] ((7) Hardness) Using a conjugated diene copolymer, the instantaneous hardness was measured using a durometer type A and a durometer type D in accordance with JIS K6253. The hardness value was measured the instant the probe of the hardness tester was lowered onto the measurement sample. In Tables 1 and 2 below, the hardness is described as hardness (JIS-A, instantaneous) and hardness (JIS-D, instantaneous), respectively. When the hardness value is less than 20 using Durometer Type D, the value using Durometer Type A is used, and when the hardness value is more than 90 using Durometer Type A, the value using Durometer Type D is used. As a guideline, a hardness of 94 on a durometer type A corresponds to a hardness of 45 on a durometer type D.

[0111] (8) Melt flow rate (MFR, unit: g / 10 min) Using a conjugated diene copolymer, MFR was measured at a temperature of 230°C and a load of 2.16 kg in accordance with JIS K7210.

[0112] ((9) Blocking resistance of pellets (blocking rate)) The blocking resistance of the pellets of the hydrogenated conjugated diene copolymer was measured by the following method. 60 g of sample pellets made of hydrogenated conjugated diene copolymer and having the same shape (cylindrical shape with a diameter of about 3 mm x 3 mm) were placed in a metal cylinder with a diameter of 5 cm, and a weight of 1160 g was placed on top of them. In this state, the cylinder was heated in a gear oven at 60°C for 24 hours, and then the state of adhesion of the pellets inside the cylinder was observed. Specifically, the pellet clumps removed from the cylinder crumble (however, pellets with poor blocking resistance do not crumble), and the mass of a clump consisting of three or more pellets was measured, and the ratio of the weight of the pellet clump to the total mass of the pellets (60 g) = the blocking rate (%) was calculated. The blocking resistance was evaluated based on the following criteria. The evaluation was carried out after adding calcium stearate equivalent to 1000 ppm to each sample pellet. <Evaluation criteria> 10: Blocking rate is less than 10% of the total mass 9: Blocking rate is 10% or more but less than 20% of the total mass 8: Blocking rate is 20% or more but less than 30% of the total mass 7: Blocking rate is 30% or more but less than 40% of the total mass 6: Blocking rate is 40% or more but less than 50% of the total mass 5: Blocking rate is 50% or more but less than 60% of the total mass 4: Blocking rate is 60% or more but less than 70% of the total mass 3: Blocking rate is 70% or more but less than 80% of the total mass 2: Blocking rate is 80% or more but less than 90% of the total mass 1: Blocking rate is 90% or more of the total mass A score of 5 or more was deemed acceptable for blocking resistance, and the higher the score, the better the product was evaluated to be in terms of suppressing blocking during transportation, facilitating compounding during compound molding, and reducing the amount of anti-blocking agent used.

[0113] (Preparation of hydrogenation catalyst) In the Production Examples and Comparative Production Examples described below, the hydrogenation catalyst used in producing the hydrogenated conjugated diene copolymers 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 placed in the vessel. 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 reaction was carried out at room temperature for about 3 days. This produced a hydrogenation catalyst.

[0114] (Component (I): Conjugated diene copolymer) A conjugated diene copolymer of a vinyl aromatic compound and a conjugated diene compound was prepared as follows. The structures and physical properties of each conjugated diene copolymer are shown in Tables 1 and 2. In the "structure" in Tables 1 and 2, A represents a polymer block (a) mainly composed of vinyl aromatic monomer units, B represents a polymer block (b) having vinyl aromatic monomer units and conjugated diene monomer units, and C represents a polymer block (c) mainly composed of conjugated diene monomer units.

[0115] <(Production Example 1) Conjugated Diene Copolymer (1)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 15 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.094 parts by mass of n-butyllithium per 100 parts by mass of the total monomers and 0.90 moles of N,N,N',N'-tetramethylethylenediamine (hereinafter referred to as "TMEDA") per mole of n-butyllithium were added, and polymerization was carried out at 65°C for 1 hour. Next, a cyclohexane solution (concentration 20% by mass) containing 20 parts by mass of butadiene and 29 parts by mass of styrene was added, and polymerization was carried out for 2 hours at 80° C. Next, a cyclohexane solution (concentration 20% by mass) containing 15 parts by mass of styrene was added, and polymerization was carried out for 1 hour at 65° C. Finally, a cyclohexane solution (concentration 20% by mass) containing 19 parts by mass of butadiene was added, and polymerization was carried out for 1 hour at 60° C. Thereafter, methanol was added to terminate the polymerization reaction. The conjugated diene copolymer obtained as described above had a styrene content (vinyl aromatic monomer units in (b) copolymer block) of 59% by mass, a polystyrene block ((a) polymer block mainly composed of vinyl aromatic monomer units) content of 30% by mass, a vinyl bond amount (total of the vinyl bond amount in (b) copolymer block and the vinyl bond amount in (c) polymer block mainly composed of conjugated diene monomer units) of 44% by mass, and a weight-average molecular weight of 85,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained conjugated diene copolymer in an amount of 100 ppm (Ti basis) 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 65°C. Next, 0.3 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 copolymer to obtain a conjugated diene copolymer (1). The hydrogenation rate of the obtained conjugated diene copolymer (1) was 98%. Other physical properties are shown in Table 1.

[0116] <(Production Example 2) Conjugated Diene Copolymer (2)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 10 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.125 parts by mass of n-butyllithium per 100 parts by mass of the total monomers and 0.50 moles of N,N,N',N'-tetramethylethylenediamine (hereinafter referred to as "TMEDA") per mole of n-butyllithium were added, and polymerization was carried out at 65°C for 1 hour. Next, a cyclohexane solution (concentration 20% by mass) containing 55 parts by mass of butadiene and 25 parts by mass of styrene was added, and polymerization was carried out for 2 hours at 80° C. Finally, a cyclohexane solution (concentration 20% by mass) containing 10 parts by mass of styrene was added, and polymerization was carried out for 1 hour at 65° C. Thereafter, methanol was added to terminate the polymerization reaction. The conjugated diene copolymer obtained as described above had a styrene content in the copolymer block of 31% by mass, a polystyrene block content of 20% by mass, a vinyl bond content of 50% by mass, and a weight average molecular weight of 70,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained conjugated diene copolymer in an amount of 100 ppm (Ti basis) 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 65°C. Next, 0.3 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 copolymer to obtain a conjugated diene copolymer (2). The hydrogenation rate of the obtained conjugated diene copolymer (2) was 98%. Other physical properties are shown in Table 1.

[0117] <(Production Example 3) Conjugated Diene Copolymer (3)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 10 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.102 parts by mass of n-butyllithium per 100 parts by mass of all monomers, 0.80 mol of N,N,N',N'-tetramethylethylenediamine (hereinafter referred to as "TMEDA") per 1 mol of n-butyllithium, and 0.04 mol of sodium-t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65°C for 1 hour. Next, a cyclohexane solution (concentration 20% by mass) containing 44 parts by mass of butadiene and 36 parts by mass of styrene was added, and polymerization was carried out for 2 hours at 65° C. Finally, a cyclohexane solution (concentration 20% by mass) containing 10 parts by mass of styrene was added, and polymerization was carried out for 1 hour at 65° C. Thereafter, methanol was added to terminate the polymerization reaction. The conjugated diene copolymer obtained as described above had a styrene content in the copolymer block of 45% by mass, a polystyrene block content of 20% by mass, a vinyl bond content of 55% by mass, and a weight average molecular weight of 80,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained conjugated diene copolymer in an amount of 100 ppm (Ti basis) 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 65°C. Next, 0.3 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 copolymer to obtain a conjugated diene copolymer (3). The hydrogenation rate of the obtained conjugated diene copolymer (3) was 98%. Other physical properties are shown in Table 1.

[0118] <(Production Example 4) Conjugated Diene Copolymer (4)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 17 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.081 parts by mass of n-butyllithium relative to 100 parts by mass of all monomers, 1.00 mol of N,N,N',N'-tetramethylethylenediamine (hereinafter referred to as "TMEDA") relative to 1 mol of n-butyllithium, and 0.04 mol of sodium-t-pentoxide relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 65°C for 1 hour. Next, a cyclohexane solution (concentration 20% by mass) containing 24 parts by mass of butadiene and 42 parts by mass of styrene was added, and polymerization was carried out for 2 hours at 65° C. Finally, a cyclohexane solution (concentration 20% by mass) containing 17 parts by mass of styrene was added, and polymerization was carried out for 1 hour at 65° C. Thereafter, methanol was added to terminate the polymerization reaction. The conjugated diene copolymer obtained as described above had a styrene content in the copolymer block of 64% by mass, a polystyrene block content of 34% by mass, a vinyl bond content of 30% by mass, and a weight average molecular weight of 90,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained conjugated diene copolymer in an amount of 100 ppm (Ti basis) 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 65°C. Next, 0.3 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 copolymer to obtain a conjugated diene copolymer (4). The hydrogenation rate of the obtained conjugated diene copolymer (4) was 98%. Other physical properties are shown in Table 1.

[0119] <(Production Example 5) Conjugated Diene Copolymer (5)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 15 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.083 parts by mass of n-butyllithium relative to 100 parts by mass of all monomers, 0.80 mol of N,N,N',N'-tetramethylethylenediamine (hereinafter referred to as "TMEDA") relative to 1 mol of n-butyllithium, and 0.04 mol of sodium-t-pentoxide relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 65°C for 1 hour. Next, a cyclohexane solution (concentration 20% by mass) containing 7 parts by mass of butadiene was added, and polymerization was continued for 1 hour at 60°C. Next, a cyclohexane solution (concentration 20% by mass) containing 24 parts by mass of butadiene and 34 parts by mass of styrene was added, and polymerization was continued for 2 hours at 65°C. Next, a cyclohexane solution (concentration 20% by mass) containing 15 parts by mass of styrene was added, and polymerization was continued for 1 hour at 65°C. Finally, a cyclohexane solution (concentration 20% by mass) containing 5 parts by mass of butadiene was added, and polymerization was continued for 1 hour at 60°C. Thereafter, methanol was added to terminate the polymerization reaction. The conjugated diene copolymer obtained as described above had a styrene content in the copolymer block of 59% by mass, a polystyrene block content of 30% by mass, a vinyl bond content of 46% by mass, and a weight average molecular weight of 94,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained conjugated diene copolymer in an amount of 100 ppm (Ti basis) 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 65°C. Next, 0.3 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 copolymer to obtain a conjugated diene copolymer (5). The hydrogenation rate of the obtained conjugated diene copolymer (5) was 98%. Other properties are shown in Table 1.

[0120] <(Production Example 6) Conjugated Diene Copolymer (6)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 10 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.190 parts by mass of n-butyllithium relative to 100 parts by mass of all monomers, 0.10 mol of N,N,N',N'-tetramethylethylenediamine (hereinafter referred to as "TMEDA") relative to 1 mol of n-butyllithium, and 0.01 mol of sodium-t-pentoxide relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 65°C for 1 hour. Next, a cyclohexane solution (concentration 20% by mass) containing 55 parts by mass of butadiene and 25 parts by mass of styrene was added, and polymerization was carried out for 2 hours at 70° C. Finally, a cyclohexane solution (concentration 20% by mass) containing 10 parts by mass of styrene was added, and polymerization was carried out for 1 hour at 65° C. Thereafter, methanol was added to terminate the polymerization reaction. The conjugated diene copolymer obtained as described above had a styrene content in the copolymer block of 31% by mass, a polystyrene block content of 20% by mass, a vinyl bond content of 12% by mass, and a weight average molecular weight of 47,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained conjugated diene copolymer in an amount of 100 ppm (Ti basis) 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 65°C. Next, 0.3 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 copolymer to obtain a conjugated diene copolymer (6). The hydrogenation rate of the obtained conjugated diene copolymer (6) was 98%. Other physical properties are shown in Table 1.

[0121] <(Production Example 7) Conjugated Diene Copolymer (7)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 15 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.058 parts by mass of n-butyllithium per 100 parts by mass of the total monomers and 0.9 moles of N,N,N',N'-tetramethylethylenediamine (hereinafter referred to as "TMEDA") per mole of n-butyllithium were added, and polymerization was carried out at 65°C for 1 hour. Next, a cyclohexane solution (concentration 20% by mass) containing 29 parts by mass of butadiene and 41 parts by mass of styrene was added, and polymerization was carried out for 2 hours at 80° C. Finally, a cyclohexane solution (concentration 20% by mass) containing 15 parts by mass of styrene was added, and polymerization was carried out for 1 hour at 65° C. Thereafter, methanol was added to terminate the polymerization reaction. The conjugated diene copolymer obtained as described above had a styrene content of 59% by mass in the copolymer block, a polystyrene block content of 30% by mass, a vinyl bond amount of 22% by mass, and a weight average molecular weight of 128,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained conjugated diene copolymer in an amount of 100 ppm (Ti basis) 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 65°C. Next, 0.3 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 copolymer to obtain a conjugated diene copolymer (7). The hydrogenation rate of the obtained conjugated diene copolymer (7) was 98%. Other physical properties are shown in Table 2.

[0122] <(Production Example 8) Conjugated Diene Copolymer (8)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 5.5 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.085 parts by mass of n-butyllithium per 100 parts by mass of the total monomers and 0.6 moles of N,N,N',N'-tetramethylethylenediamine (hereinafter referred to as "TMEDA") per mole of n-butyllithium were added, and polymerization was carried out at 65°C for 1 hour. Next, a cyclohexane solution (concentration 20% by mass) containing 18 parts by mass of butadiene and 71 parts by mass of styrene was added, and polymerization was carried out for 2 hours at 65° C. Finally, a cyclohexane solution (concentration 20% by mass) containing 5.5 parts by mass of styrene was added, and polymerization was carried out for 1 hour at 65° C. Thereafter, methanol was added to terminate the polymerization reaction. The conjugated diene copolymer obtained as described above had a styrene content in the copolymer block of 80% by mass, a polystyrene block content of 11% by mass, a vinyl bond content of 10% by mass, and a weight average molecular weight of 83,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained conjugated diene copolymer in an amount of 100 ppm (Ti basis) 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 65°C. Next, 0.3 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 copolymer to obtain a conjugated diene copolymer (8). The hydrogenation rate of the obtained conjugated diene copolymer (8) was 98%. Other physical properties are shown in Table 2.

[0123] <(Production Example 9) Conjugated Diene Copolymer (9)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 12 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.081 parts by mass of n-butyllithium per 100 parts by mass of the total monomers and 0.20 moles of N,N,N',N'-tetramethylethylenediamine (hereinafter referred to as "TMEDA") per mole of n-butyllithium were added, and polymerization was carried out at 65°C for 1 hour. Next, a cyclohexane solution (concentration 20% by mass) containing 15 parts by mass of butadiene and 61 parts by mass of styrene was added, and polymerization was carried out for 2 hours at 70° C. Finally, a cyclohexane solution (concentration 20% by mass) containing 12 parts by mass of styrene was added, and polymerization was carried out for 1 hour at 65° C. Thereafter, methanol was added to terminate the polymerization reaction. The conjugated diene copolymer obtained as described above had a styrene content in the copolymer block of 80% by mass, a polystyrene block content of 24% by mass, a vinyl bond content of 30% by mass, and a weight average molecular weight of 105,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained conjugated diene copolymer in an amount of 100 ppm (Ti basis) 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 65°C. Next, 0.3 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 copolymer to obtain a conjugated diene copolymer (9). The hydrogenation rate of the obtained conjugated diene copolymer (9) was 98%. Other physical properties are shown in Table 2.

[0124] <(Production Example 10) Conjugated Diene Copolymer (10)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 4 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.10 parts by mass of n-butyllithium per 100 parts by mass of the total monomers and 0.40 moles of N,N,N',N'-tetramethylethylenediamine (hereinafter referred to as "TMEDA") per mole of n-butyllithium were added, and polymerization was carried out at 65°C for 1 hour. Next, a cyclohexane solution (concentration 20% by mass) containing 27 parts by mass of butadiene and 65 parts by mass of styrene was added, and polymerization was carried out for 2 hours at 70° C. Finally, a cyclohexane solution (concentration 20% by mass) containing 4 parts by mass of styrene was added, and polymerization was carried out for 1 hour at 65° C. Thereafter, methanol was added to terminate the polymerization reaction. The conjugated diene copolymer obtained as described above had a styrene content in the copolymer block of 71% by mass, a polystyrene block content of 8% by mass, a vinyl bond content of 40% by mass, and a weight average molecular weight of 80,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained conjugated diene copolymer in an amount of 100 ppm (Ti basis) 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 65°C. Next, 0.3 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 copolymer to obtain a conjugated diene copolymer (10). The hydrogenation rate of the obtained conjugated diene copolymer (10) was 98%. Other physical properties are shown in Table 2.

[0125] (Component (II): Radical initiator) 2-Phenylimidazole (Tokyo Chemical Industry Co., Ltd.)

[0126] (Component (III): at least one selected from the group consisting of epoxy resins, maleimide resins, polyphenylene ether resins, liquid crystal polyester resins, and fluorine-based resins (excluding component (I))) <Epoxy resin> Bisphenol A epoxy resin EXA-850CRP (DIC Corporation) Naphthalene-type epoxy resin HP-4710 (DIC Corporation)

[0127] <Maleimide resin> Maleimide resin MIR-3000-70MT (Nippon Kayaku Co., Ltd.)

[0128] <Phenoxy resin> YP-50S (Nippon Steel Chemicals Co., Ltd.)

[0129] (Component (IV): Hardener (excluding component (II))) Phenolic hardener KA-1163 (DIC Corporation)

[0130] [Method for measuring physical properties of resin composition] ((1) Dielectric loss tangent and dielectric constant) The dielectric loss tangent and dielectric constant at 10 GHz were measured by the cavity resonance method. The measurement devices used were a network analyzer (N5230A, manufactured by Agilent Technologies) and a cavity resonator (Cavity Resornator CP series, manufactured by Kanto Electronics Application Development Co., Ltd.). The measurement sample was a test piece measuring 2.6 mm wide x 80 mm long cut out from the cured film described below. Using the dielectric loss tangent and dielectric constant obtained above, the following examples and comparative examples were evaluated according to the following criteria.

[0131] <Evaluation criteria for Examples 1 to 6 and Comparative Examples 1 to 5> The evaluation was based on the difference in dielectric loss tangent and dielectric constant between Comparative Example 1, which does not contain a conjugated diene copolymer, and each Example or Comparative Example (Comparative Example 1 - each Example or Comparative Example). Dielectric tangent ◎: 0.0030 or more ○: 0.0025 or more, less than 0.0030 △: 0.0018 or more, less than 0.0025 ×: Less than 0.0018 (including equal and positive differences) dielectric constant ◎: 0.45 or more ○: 0.35 or more, less than 0.45 △: 0.25 or more, less than 0.35 ×: Less than 0.25 (including equal and positive differences)

[0132] (2) Adhesion to copper foil Each resin composition described below was applied to a polyimide film, the solvent was dried off, and then a 35 μm thick copper foil was placed on top of the film. The film was then heated and pressed at 100°C and 1 MPa for 2 minutes to laminate the copper foil, producing a polyimide film-resin composition-copper foil laminate. The resin composition was cured by heating the laminate at 180°C for 1 hour, and the cured laminate was used as an adhesive sample. A 1 cm wide cut was made in the laminate, and a peel strength test was performed in which the copper foil was peeled off in a 90° direction at a pulling speed of 50 mm / min. A higher peel strength indicates higher adhesion. Using the peel strength obtained above, the following Examples and Comparative Examples were evaluated according to the following criteria.

[0133] <Evaluation criteria for Examples 1 to 6 and Comparative Examples 1 to 5> Evaluation was made based on the difference in peel strength between Comparative Example 1, which does not contain a conjugated diene copolymer, and each Example or Comparative Example (Comparative Example 1 - each Example or Comparative Example). ◎: 0.20 or more ○: 0.15 or more, less than 0.20 △: 0.10 or more, less than 0.15 ×: Less than 0.10 (including equal and positive differences)

[0134] ((3) Melt viscosity of the cured product) The melt viscosity of the resin composition layer in the cured film produced in the examples and comparative examples was Measurements were performed using a dynamic viscoelasticity measuring device (TA Instruments Japan, "ARES-G2"). This measurement was performed on a 1 g sample taken from the resin composition layer using parallel plates with a diameter of 8 mm. The measurement conditions were a starting temperature of 50°C to 250°C, a heating rate of 5°C / min, a temperature measurement interval of 2.5°C, and an oscillation frequency of 1 Hz / deg. The melt viscosity was calculated from the measured values.

[0135] <Evaluation criteria for Examples 1 to 6 and Comparative Examples 1 to 5> Evaluation was made based on the difference in melt viscosity between Comparative Example 1, which does not contain a conjugated diene copolymer, and each Example or Comparative Example (Comparative Example 1 - each Example or Comparative Example). ◎: 3000 or more ○: 2000 or more, less than 3000 △: 1000 or more, less than 2000 ×: Less than 1000 (including equal and positive differences)

[0136] ((4) Varnish Stability) The resin varnishes prepared in the examples and comparative examples were placed in plastic containers and left to stand in a refrigerator at 5°C for 1 to 5 days to confirm the stability of the resin varnishes.

[0137] <Evaluation criteria for Examples 1 to 6 and Comparative Examples 1 to 5> ◎: No sedimentation of resin varnish components occurs at the bottom of the container after leaving it for 5 days 〇: No precipitation of resin varnish components occurred at the bottom of the container after leaving it for 4 days, but precipitation of resin varnish components occurred at the bottom of the container on the 5th day. △: No precipitation of resin varnish components occurred at the bottom of the container after leaving it standing for 3 days, but precipitation of resin varnish components occurred at the bottom of the container on the 4th day. ×: No precipitation of resin varnish components occurred at the bottom of the container after leaving it to stand for 2 days, but precipitation of resin varnish components occurred at the bottom of the container on the 3rd day.

[0138] [Preparation of Resin Composition] (Examples 1 to 6), (Comparative Examples 1 to 5) The component ratios and physical properties of the resin compositions are shown in the following Tables 3 and 4. In Tables 3 and 4, "parts" means "parts by mass." First, each component was added to toluene (special grade product manufactured by Wako Pure Chemical Industries, Ltd., used as is) according to the formulation shown in Tables 3 and 4 below, stirred and dissolved to prepare a resin varnish (resin composition) with a concentration of 20% by mass to 50% by mass. The resin varnish was applied to a release-treated Kapton film at a speed of 30 mm / sec, and then dried in a nitrogen-air flow ventilator at 100°C for 30 minutes to obtain a film. The obtained film was cured in a nitrogen-air flow ventilator at 200°C for 90 minutes to obtain a cured film. The cured film was used as an evaluation sample.

[0139] As can be seen from Tables 3 and 4 below, it was revealed that the cured products using the conjugated diene copolymers of the examples have an excellent balance of dielectric properties. It was found that the cured products of the present invention are suitable for printed wiring boards using glass cloth and metal laminates.

[0140] [Table 1]

[0141] [Table 2]

[0142] [Table 3]

[0143] [Table 4] [Industrial Applicability]

[0144] The resin composition and cured product of the present invention have industrial applicability as materials for films, prepregs, electronic circuit boards, and next-generation communication boards.

Claims

1. Component (I): A conjugated diene copolymer comprising vinyl aromatic monomer units and conjugated diene monomer units, Conjugated diamines that satisfy the following conditions (i), (ii), (iii), and (iv): an ene-based copolymer; and at least one component selected from the group consisting of the following components (II) to (IV): Resin composition. <Condition (i)> The composition contains at least one (a) polymer block mainly composed of a vinyl aromatic monomer unit, and the content of the (a) polymer block mainly composed of a vinyl aromatic monomer unit is 10% by mass or more and 40% by mass or less. <Condition (ii)> (b) At least one copolymer block composed of a vinyl aromatic monomer unit and a conjugated diene monomer unit is contained, and the content of the vinyl aromatic monomer unit in the copolymer block (b) is 30% by mass or more and 79% by mass or less. <Condition (iii)> The instantaneous hardness measured with a durometer type A in accordance with JIS K6253 is 60 or more, and the instantaneous hardness measured with a durometer type D is 65 or less. <Condition (iv)> The MFR value measured in accordance with JIS K7210 under conditions of a temperature of 230°C and a load of 2.16 kg is 10 (g / 10 min) or more. Component (II): Radical initiator Component (III): At least one resin selected from the group consisting of epoxy resins, maleimide resins, polyphenylene ether resins, liquid crystal polyester resins, and fluorine-containing resins (excluding component (I)). Component (IV): Curing agent (excluding component (II))

2. The instantaneous hardness measured with a durometer type A in accordance with JIS K6253 is 85 or more, and the instantaneous hardness measured with a durometer type D is 45 or less. The resin composition according to claim 1.

3. the conjugated diene copolymer has an MFR value of 15 (g / 10 min) or more, measured in accordance with JIS K7210 at a temperature of 230°C and a load of 2.16 kg; The resin composition according to claim 1.

4. the conjugated diene copolymer further contains (c) at least one polymer block mainly composed of conjugated diene monomer units, the content of the polymer block (c) mainly composed of a conjugated diene monomer unit is 3% by mass or more; The resin composition according to claim 1.

5. the conjugated diene copolymer further contains (c) at least one polymer block mainly composed of conjugated diene monomer units, the sum of the vinyl bond content in the (b) copolymer block and the vinyl bond content in the (c) polymer block mainly composed of conjugated diene monomer units is 30% by mass or more; The resin composition according to claim 1.

6. the conjugated diene copolymer further contains (c) at least one polymer block mainly composed of conjugated diene monomer units, the content of the polymer block (c) mainly composed of conjugated diene monomer units is 3% by mass or more and 20% by mass or less; The resin composition according to claim 1.

7. Contains the component (III), The resin composition according to claim 1 , wherein the component (III) comprises an epoxy resin.

8. Contains the component (III), The resin composition according to claim 1 , wherein the component (III) comprises a maleimide resin.

9. A cured product of the resin composition according to any one of claims 1 to 3.

10. A resin film comprising the resin composition according to claim 1 .

11. A substrate; The resin composition according to any one of claims 1 to 3, Prepreg is a composite material.

12. The substrate is a glass cloth. The prepreg according to claim 11.

13. A laminate comprising the resin film according to claim 10 and a metal foil.

14. A cured product of the prepreg according to claim 11, a metal foil, A laminate having:

15. A material for electronic circuit boards, comprising the cured product according to claim 9.

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