Block copolymers, resin compositions, cured products, resin films, prepregs, laminates, and materials for electronic circuit boards

Abstract

The present invention provides a block copolymer which comprises a polymer block (B) that is mainly composed of a conjugated diene monomer unit, and a polymer block (A) that is mainly composed of a vinyl aromatic monomer unit and / or a polymer block (C) that is composed of a vinyl aromatic monomer unit and a conjugated diene monomer unit, and which satisfies the conditions (i) to (iii) described below. Condition (i): The weight average molecular weight of the block copolymer is 35,000 or less. Condition (ii): The content of the vinyl aromatic monomer unit in the block copolymer is 30% by mass or more. Condition (iii): Relative to 100 parts by mass of the block copolymer, 5 parts by mass or more of the polymer block (B) is positioned at ends of the block copolymer.

Description

[Technical Field]

[0001] The present invention relates to a block copolymer, a resin composition, a cured product, a resin film, a prepreg, a laminate, and a material for an electronic circuit board. [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] BACKGROUND ART In order to obtain materials with small dielectric loss, cured resins containing, as their main component, a thermosetting resin such as an epoxy resin, which has a low dielectric constant and a low dielectric dissipation factor, and excellent mechanical properties such as strength and heat resistance, or a thermoplastic resin such as a polyphenylene ether resin, have been studied and disclosed. However, the 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] In order to improve these problems, many resin compositions containing a rubber component as a modifier and cured products thereof have been proposed (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-147486 [Patent Document 2] 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 and 2 still have insufficient low dielectric constants and low dielectric loss tangents, and also have problems in that the strength and heat resistance are reduced by the addition of the modifiers.

[0007] Therefore, an object of the present invention is to provide a block copolymer that can give a cured product having a low dielectric constant and a low dielectric loss tangent and also excellent strength and heat resistance, and a resin composition containing the block copolymer. [Means for solving the problem]

[0008] As a result of intensive research aimed at solving the above-mentioned problems of the conventional art, the present inventors have found that a cured product of a resin composition containing a block copolymer having a predetermined structure has a low dielectric constant and a low dielectric dissipation factor, and is also excellent in strength and heat resistance, thereby completing the present invention. That is, the present invention is as follows.

[0009] [1] a polymer block (B) mainly composed of conjugated diene monomer units; The polymer block (A) mainly comprises a vinyl aromatic monomer unit, and / or the polymer block (C) comprises a vinyl aromatic monomer unit and a conjugated diene monomer unit. A block copolymer comprising: the conjugated diene monomer units of the polymer block (B) and the polymer block (C) in the block copolymer contain units (a) derived from a 1,2-bond and / or a 3,4-bond and units (b) derived from a 1,4-bond, and the content of the units (a) derived from a 1,2-bond and / or a 3,4-bond is 10 to 95% when the total content of the conjugated diene monomer units of the polymer block (B) and the polymer block (C) is taken as 100%, A block copolymer that satisfies the following conditions (i) to (iii): <Condition (i)> The weight average molecular weight of the block copolymer is 35,000 or less. <Condition (ii)> The content of vinyl aromatic monomer units in the block copolymer is 30% by mass or more. <Condition (iii)> Five parts by mass or more of the polymer block (B) is located at the terminal of the block copolymer, based on 100 parts by mass of the block copolymer. 〔2〕 the content of the units (a) derived from a 1,2-bond and / or a 3,4-bond is 25 to 85% when the total content of the conjugated diene monomer units of the polymer block (B) and the polymer block (C) in the block copolymer is taken as 100%; The block copolymer described in [1] above. 〔3〕 Component (I): the block copolymer described in [1] above; Contains at least one component selected from the group consisting of the following components (II) to (IV): Resin composition. Component (II): Radical initiator Component (III): Polar resin (excluding component (I)) Component (IV): Hardener (excluding component (II)) 〔4〕 The component (III) is at least one selected from the group consisting of epoxy resins, polyimide resins, polyphenylene ether resins, liquid crystal polyester resins, and fluorine-based resins. 〔3〕 The resin composition according to claim 1. 〔5〕 A cured product comprising the block copolymer described in [1] above. 〔6〕 The aforementioned [3] or [4] A cured product of the resin composition described in 1. 〔7〕 The aforementioned [3] or [4] A resin film comprising the resin composition according to claim 1. 〔8〕 a substrate; [3] or [4] A prepreg, which is a composite with the resin composition described in 1. 〔9〕 The substrate is a glass cloth. 〔8〕 The prepreg according to claim 1. 〔10〕 The aforementioned 〔7〕 A laminate comprising the resin film according to claim 1 and a metal foil. 〔11〕 The aforementioned [8] or [9] A laminate comprising a cured product of the prepreg according to claim 1 and a metal foil. 〔12〕 The aforementioned [5] or [6] A material for electronic circuit boards, comprising the cured product according to claim 1. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a block copolymer and a resin composition containing the block copolymer, which give a cured product having a low dielectric constant and a low dielectric loss tangent and excellent strength and heat 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] [Block copolymer] The block copolymer of this embodiment is The copolymer has a polymer block (B) mainly composed of conjugated diene monomer units (hereinafter may be referred to as polymer block (B)), a polymer block (A) mainly composed of vinyl aromatic monomer units (hereinafter may be referred to as polymer block (A)), and / or a polymer block (C) composed of vinyl aromatic monomer units and conjugated diene monomer units (hereinafter may be referred to as polymer block (C)). The block copolymer of this embodiment satisfies the following conditions (i) to (iii). <Condition (i)> The weight average molecular weight of the block copolymer is 35,000 or less. <Condition (ii)> The content of vinyl aromatic monomer units in the block copolymer is 30% by mass or more. <Condition (iii)> Five parts by mass or more of the polymer block (B) is located at the terminal of the block copolymer, based on 100 parts by mass of the block copolymer.

[0013] In this specification, the term "conjugated diene monomer unit" refers to a polymer block formed by polymerization of a conjugated diene compound, or a structural unit derived from a conjugated diene compound in a block copolymer. Conjugated diene compounds are diolefins 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. These may be used alone or in combination of two or more. The conjugated diene compound may be a bio-derived compound.

[0014] In this specification, the term "vinyl aromatic monomer unit" refers to a polymer block formed by polymerization of a vinyl aromatic compound, or a structural unit derived from a vinyl aromatic compound in a block copolymer. 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.

[0015] The block copolymer of the present embodiment has a polymer block (B) mainly composed of conjugated diene monomer units, and a polymer block (A) mainly composed of vinyl aromatic monomer units and / or a polymer block (C) composed of vinyl aromatic monomer units and conjugated diene monomer units. The polymer block (A) is mainly composed of vinyl aromatic monomer units, and the term "mainly composed" means that no other monomers have been intentionally added. The polymer block (B) is mainly composed of conjugated diene monomer units. The term "mainly composed" means that no other monomers are intentionally added.

[0016] When the block copolymer of the present embodiment contains the polymer block (A), the content of the polymer block (A) 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 block copolymer before hydrogenation or the hydrogenated block copolymer after hydrogenation as a sample.

[0017] The block copolymer of the present embodiment essentially contains polymer block (B) and further contains polymer block (A) and / or polymer block (C). The block copolymer may have a basic skeleton formed by these blocks having a repeating structure.

[0018] The polymer block (C) is composed of a vinyl aromatic monomer unit and a conjugated diene monomer unit, and no other monomers than these two types are intentionally copolymerized. The polymer block (C) can be distinguished from the polymer blocks (A) and (B) in that it has a structure in which vinyl aromatic monomer units and conjugated diene monomer units are intentionally used as constituent units. The vinyl aromatic compound and the conjugated diene compound used to form the vinyl aromatic monomer units and the conjugated diene monomer units contained in the polymer block (C) may be any compounds that can be used in the polymer block (A) and the polymer block (B). The distribution state of the vinyl aromatic monomer units in the polymer block (C) is not particularly limited, and the vinyl aromatic monomer units may be distributed uniformly or tapered in the random copolymer block. In addition, there may be a plurality of portions where the vinyl aromatic monomer units are distributed uniformly and / or a plurality of portions where the vinyl aromatic monomer units are distributed tapered, and there may be a plurality of segments with different contents of the vinyl aromatic monomer units. When the block copolymer of the present embodiment contains the polymer block (C), the content of the polymer block (C) can be measured by the NMR method.

[0019] The block copolymer of the present embodiment may have a copolymer block (D) obtained by copolymerizing a compound other than the polymer blocks (A) to (C) with a conjugated diene compound and / or a vinyl aromatic compound, within the range that does not impair the intended dielectric performance of the cured product, i.e., within the range that does not impair the low dielectric constant and low dielectric loss tangent. For example, when the block copolymer of the present embodiment containing the copolymer block (D) is produced by anionic polymerization, methyl methacrylate (MMA) can be copolymerized with a vinyl aromatic compound or a conjugated diene compound. However, if MMA is contained, the dielectric performance of the block copolymer of the present embodiment tends to decrease, i.e., the dielectric constant and / or dielectric loss tangent tends to increase. The structure of the block copolymer of the present embodiment is not particularly limited, but examples thereof include those having a structure represented by the following formula:

[0020] (bc) n , b-(cb) n , (bc) m -X, [(bc) n ] m -X, [b-(cb) n ] m -X, [(bc) n -b] m -X, (ab) n , b-(ab) n , (ba) m -X, [(ba)n ] m -X, [b-(ab) n ] m -X, [(ab) n -a] m -X, [(ba) n -b] m -X, c-(ab) n , c-(bab) n , ac-(ab) n , ac-(ba) n -b, [(bab) n -c] m -X, a-(cb) n , a-(bcb) n , ca-(bc) n , ca-(cb) n , ca-(bc) n -b, [(bcb) n -a] m -X, b-(ac) n , b-(ca) n , b-(cac) n , b-(aca) n , [(bac) n ] m -X, [b-(ac) n ] m -X, [b-(cac) n ] m -X, [b-(aca) n ] m -X In the above general formulas, a represents the polymer block (A), b represents the polymer block (B), and c represents the polymer block (C). n is an integer of 1 or more, and preferably an integer of 1 to 5. m is an integer of 2 or more, and preferably an integer of 2 to 11. X represents a residue of a coupling agent or a residue of a multifunctional initiator.

[0021] <Condition (iii)> The block copolymer of the present embodiment has polymer block (B) as an essential component, at least one of the terminals of the block copolymer is polymer block (B), and the amount of polymer block (B) at that terminal is 5 parts by mass or more per 100 parts by mass of the block copolymer. The polymer block (B) is primarily composed of conjugated diene monomer units. The conjugated diene monomer units have radical reactivity, and when preparing a cured product of the resin composition of this embodiment, the block copolymers react with each other and / or with components (II), (III), and (IV), which will be described later. This tends to improve the strength and heat resistance of the resin composition and cured product of this embodiment. Furthermore, the aforementioned reactions suppress the reduction in polymer mobility and polarization due to an external electric field, and the resin composition and cured product of this embodiment tend to have a low dielectric loss tangent and a low dielectric constant.

[0022] Furthermore, in the block copolymer of this embodiment, the polymer block (B), which serves as a reaction site, has a size of 5 parts by mass or more, and at least one such polymer block (B) of 5 parts by mass or more is present at the terminal of the block copolymer. This reduces steric hindrance compared to when the polymer block (B) is present within the polymer chain of the block copolymer. This increases the proximity of the polymer block (B) to the polymer chains of the block copolymer (described below) and other block copolymers during curing, and also increases the proximity of the block copolymers themselves. This increases the reaction rate between the polymer block (B) and components (II), (III), and (IV), and resin compositions and cured products containing the block copolymer of this embodiment tend to exhibit high strength and heat resistance, as well as low dielectric tangent and dielectric constant. The amount of the terminal polymer block (B) is 5 parts by mass or more relative to 100 parts by mass of the block copolymer of this embodiment. When the amount of the terminal polymer block (B) is 5 parts by mass or more relative to 100 parts by mass of the block copolymer, whether the portion other than the terminal is the polymer block (A) or the polymer block (C), sufficient reactivity with components (II), (III), and (IV) can be ensured, and the resin composition and cured product described below tend to exhibit sufficient strength and have a low dielectric loss tangent and a low dielectric constant. The amount of the terminal polymer block (B) is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and even more preferably 20 parts by mass or more, per 100 parts by mass of the block copolymer. The amount of the terminal polymer block (B) can be controlled within the above range by adjusting the polymerization conditions such as the amount of monomer added, the timing of addition, the polymerization temperature, and the polymerization time.

[0023] The block copolymer of this embodiment satisfies the conditions (i) and (ii). <Condition (i)> The weight average molecular weight of the block copolymer is 35,000 or less. The weight-average molecular weight can be determined by measuring the molecular weight of a peak in a chromatogram obtained by gel permeation chromatography (GPC) based on a calibration curve (prepared using the peak molecular weight of the standard polystyrene) obtained by measuring commercially available standard polystyrene. Specifically, it can be measured by the method described in the Examples below. The molecular weight distribution is the ratio of the weight average molecular weight (Mw) to the weight average molecular weight (Mn). The single-peak molecular weight distribution of the block copolymer of this embodiment measured by GPC is preferably 5.0 or less, more preferably 4.0 or less, even more preferably 3.0 or less, and even more preferably 2.5 or less. The weight-average molecular weight of the block copolymer of this embodiment is 35,000 or less, and thus compatibility with component (III): a polar resin and component (IV): a curing agent constituting the resin composition of this embodiment, which will be described later, is improved, and the strength and heat resistance of the resin composition and the cured product are improved, and the dielectric loss tangent and dielectric constant tend to be lower. Furthermore, when a prepreg is produced using the resin composition of the present embodiment described below, when a substrate such as a glass cloth described below is immersed in a varnish described below, the weight-average molecular weight of the block copolymer of the present embodiment is 35,000 or less, and this improves the permeability into the substrate, which tends to enable the production of a uniform prepreg. From the above viewpoints, the weight-average molecular weight of the block copolymer of this embodiment is preferably 30,000 or less, more preferably 25,000 or less, even more preferably 20,000 or less, even more preferably 15,000 or less, and still more preferably 10,000 or less. The lower limit of the weight-average molecular weight is not particularly limited, but is preferably 500 or more from the viewpoint of suppressing stickiness of the block copolymer of this embodiment and improving handleability. The weight average molecular weight and molecular weight distribution of the block copolymer of this embodiment can be controlled within the above numerical ranges by adjusting the polymerization conditions such as the amount of monomer added, the timing of addition, the polymerization temperature, and the polymerization time.

[0024] <Condition (ii)> The content of the vinyl aromatic monomer unit in the block copolymer of this embodiment is 30% by mass or more. As described above, since the content of polymer block (B) in the block copolymer of this embodiment is 5% by mass or more, the upper limit of the content of vinyl aromatic monomer units is 95% by mass or less. In terms of solubility parameter, the vinyl aromatic monomer units tend to be more compatible with the components (II), (III) and (IV) described below than the conjugated diene monomer units. By setting the content of vinyl aromatic monomer units in the block copolymer to 30% by mass or more, compatibility with components (II), (III), and (IV) described below is improved, and the strength of the resin composition and cured product of this embodiment tends to be improved, and the dielectric loss tangent and dielectric constant tend to be lowered. In view of the above, the content of vinyl aromatic monomer units in the block copolymer of the present embodiment is preferably 33% by mass or more, more preferably 35% by mass or more, even more preferably 37% by mass or more, still more preferably 40% by mass or more, and still more preferably 43% by mass or more.

[0025] On the other hand, there is a certain degree of correlation between dielectric performance and curing, and as described above, by having the polymer block (B) at the end of the block copolymer of this embodiment in a mass ratio of 5 parts by mass or more per 100 parts by mass of the block copolymer, the reactivity of the block copolymer of this embodiment with components (II), (III), and (IV) and between the block copolymers themselves can be ensured. Furthermore, if the block copolymer of this embodiment reacts with or is compatible with the cured resin, making it difficult for the molecular chains of the block copolymer to move, the dielectric loss tangent and dielectric constant tend to be low. Therefore, from the viewpoint of the dielectric performance of the cured product, it is preferable to design the structure of the block copolymer taking into account the influence of the reactivity and compatibility between the block copolymer and the cured resin.

[0026] In the block copolymer of the present embodiment, by setting the content of vinyl aromatic monomer units to 30% by mass or more, compatibility between the block copolymer and components (II), (III), and (IV) can be ensured, and entanglement due to aggregation of polymers composed of vinyl aromatic monomer units occurs to a certain extent, thereby maintaining strength and achieving the effects of lowering the dielectric loss tangent and the dielectric constant. When the content of vinyl aromatic monomer units in the block copolymer of this embodiment is 30% by mass or more, the strength and heat resistance of the cured product tend to be improved, and the dielectric loss tangent and dielectric constant tend to be lower. Furthermore, when a resin containing an aromatic ring, such as a polyphenylene ether resin, is used as component (III): polar resin, which will be described later, the block copolymer of the present embodiment has a vinyl aromatic monomer unit content of 30 mass% or more, which tends to improve compatibility and increase the strength of the cured product. The content of the vinyl aromatic monomer unit in the block copolymer of the present embodiment can be controlled to fall within the above-mentioned range by adjusting the polymerization conditions, such as the amount of monomer added, the timing of addition, and the polymerization temperature, and can be calculated by the method described in the Examples below.

[0027] In the block copolymer of this embodiment, the conjugated diene monomer units of the polymer block (B) and the polymer block (C) contain units (a) derived from 1,2-bonds and / or 3,4-bonds and units (b) derived from 1,4-bonds. When the total content of the conjugated diene monomer units of the polymer block (B) and the polymer block (C) is taken as 100%, the content of the units (a) derived from 1,2-bonds and / or 3,4-bonds is preferably 10 to 95%, more preferably 15 to 90%, even more preferably 20 to 85%, and even more preferably 25 to 80% or less, from the viewpoints of the reactivity between the block copolymers during curing to obtain a cured product and the reactivity of the block copolymer with components (III) and (IV), which will be described later. In addition, when both 1,2-bonds and 3,4-bonds are contained, the total content of 1,2-bonds and 3,4-bonds is the content of units (a). The content of the unit (a) can be controlled by using a regulator such as a polar compound during polymerization, and can be calculated by the method described in the examples below.

[0028] Examples of the regulator include tertiary amine compounds and ether compounds, with 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. The amount of the regulator is preferably 0.1 mol or more, more preferably 0.5 mol or more, and even more preferably 1.0 mol or more, per mol of the polymerization initiator described below.

[0029] The block copolymer of the present embodiment may contain a block copolymer in which the aliphatic double bonds based on a conjugated diene compound are hydrogenated to an extent that does not impair the curing reaction during production of the cured product, thereby improving the heat resistance of the cured product. The method for hydrogenating the block copolymer is not particularly limited, and any conventionally known method can be applied.

[0030] In the hydrogenation reaction, a hydrogenation catalyst can be used. Examples of hydrogenation catalysts 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, or Zr. Specific examples of the hydrogenation catalyst that can be used include the hydrogenation catalysts described in Japanese Patent Publication Nos. 42-8704, 43-6636, 63-4841, 1988-37970, 1989-53851, and 2-9041. Preferred hydrogenation catalysts include titanocene compounds and reducing organometallic compounds. The titanocene compound may be one described in JP-A-8-109219. Examples of the titanocene compound include 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 a combination of two of them. Examples of the reducing organometallic compound include organic alkali metal compounds such as organolithium compounds, organomagnesium compounds, organoaluminum compounds, organoboron compounds, and organozinc compounds, which may be used singly or in combination of two or more.

[0031] The hydrogenation rate of the block copolymer 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 temperature during the hydrogenation reaction is preferably 55 to 200°C, more preferably 60 to 170°C, and even more preferably 65 to 160°C. The hydrogen pressure used in the hydrogenation reaction is usually 0.1 to 15 MPa, preferably 0.2 to 10 MPa, and more preferably 0.3 to 5 MPa. The hydrogenation reaction time is usually 3 minutes to 10 hours, and preferably 10 minutes to 5 hours. The hydrogenation reaction can be carried out using either a batch process, a continuous process, or a combination thereof.

[0032] When the curing reaction for obtaining the cured product of this embodiment described below is a radical reaction, the hydrogenation rate of the block copolymer of this embodiment is preferably 5 to 95%, more preferably 10 to 90%, and even more preferably 13 to 87%, from the viewpoint of the balance between curing reactivity and thermal stability. When the curing reaction for obtaining the cured product is other than a radical reaction, the hydrogenation rate can be selected arbitrarily between 0 and 100%, from the viewpoint of heat resistance and compatibility between the block copolymer of this embodiment and other components.

[0033] [Method for producing block copolymer] The block copolymer of this embodiment can be produced, for example, by living anionic polymerization using a polymerization initiator such as an organic alkali metal compound in a hydrocarbon solvent.

[0034] Examples of hydrocarbon solvents include 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.

[0035] Examples of the polymerization initiator 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 the alkali metal include lithium, sodium, and potassium. Examples of organic alkali metal compounds include aliphatic and aromatic hydrocarbon lithium compounds having 1 to 20 carbon atoms, including compounds containing one lithium atom per molecule, dilithium compounds containing multiple lithium atoms per molecule, trilithium compounds, and tetralithium compounds. Specific examples of organic alkali metal compounds include 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.

[0036] As a method for polymerizing a vinyl aromatic compound and a conjugated diene polymer using an organic alkali metal compound as a polymerization initiator, a conventionally known method can be applied. The polymerization method may be, for example, batch polymerization, continuous polymerization, or a combination of these. In particular, batch polymerization is suitable for obtaining a block copolymer having excellent heat resistance. The polymerization temperature is preferably 0°C to 180°C, more preferably 30°C to 150°C. The polymerization time varies depending on the conditions, but is usually within 48 hours, preferably 0.1 to 10 hours. 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 can maintain the monomer and solvent in a liquid phase within the above temperature range. Furthermore, care must be taken to prevent impurities that may inactivate the catalyst and living polymer, such as water, oxygen, and carbon dioxide, from entering the polymerization system.

[0037] Furthermore, at the end of the polymerization step, a coupling reaction may be carried out by adding a necessary amount of a bifunctional or higher functional coupling agent within a range that satisfies the above-mentioned conditions (i) to (iii), but 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.

[0038] The bifunctional coupling agent is not particularly limited and any known bifunctional coupling agent can be used. 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. Furthermore, as the trifunctional or higher polyfunctional coupling agent, any known agent can be used, and there is no particular limitation. Examples of polyfunctional coupling agents with three or more functionalities include, but are not limited to, polyalcohols with three or more functionalities, epoxidized soybean oil, polyhydric epoxy compounds such as diglycidyl bisphenol A and 1,3-bis(N-N'-diglycidylaminomethyl)cyclohexane, and compounds of the general formula R4-nSiX n (wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 3 to 4), for example, methylsilyl trichloride, t-butylsilyl trichloride, silicon tetrachloride, and bromides thereof, and silicon halide compounds represented by the general formula R4-nSnX n (wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 3 to 4), for example, polyvalent halogen compounds such as methyltin trichloride, t-butyltin trichloride, and tin tetrachloride. Dimethyl carbonate, diethyl carbonate, etc. may also be used.

[0039] If necessary, the catalyst residue can be removed from the solution of the block copolymer of this embodiment obtained as described above, and the block copolymer can be separated from the solution. The polymerization initiator used in producing a block copolymer by anionic living polymerization and the compound containing a metal atom in the hydrogenation catalyst in the hydrogenation reaction described above tend to react with moisture in the air, etc., during a desolvation step, etc., to generate a specific metal compound that remains in the block copolymer. When these metal compounds are contained in a cured product using the block copolymer of this embodiment, the dielectric constant and dielectric loss tangent tend to increase, and further, ion migration tends to occur easily when used as an electronic material. Examples of the remaining metal compounds 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. In order to achieve a low dielectric constant and a low dielectric loss tangent in the resin composition and the cured product of this embodiment and to make ion migration less likely to occur, the amount of metal compounds remaining in the block copolymer is preferably 150 ppm or less, more preferably 130 ppm or less, even more preferably 100 ppm or less, and even more preferably 90 ppm or less, in terms of the amount of residual metal. Specific examples of residual metals include Ti, Ni, Li, and Co.

[0040] The method for reducing the amount of residual metal in the block copolymer of this embodiment can be any conventionally known method, and is not particularly limited. Examples include a method of adding water and carbon dioxide gas after the hydrogenation reaction of the block copolymer to neutralize the hydrogenation catalyst residue; and a method of adding water, carbon dioxide gas, and an acid to neutralize the hydrogenation catalyst residue. Specifically, the method described in Japanese Patent Application No. 2014-557427 can be applied. Even when these metal removal methods are used, water containing hydroxides of metal compounds is mixed in during the desolvation process of the block copolymer, so the amount of residual metal is generally about 1 to 15 ppm. Therefore, it is preferable to remove 20% or more of the amount of metal added to the block copolymer, more preferably 30% or more, even more preferably 40% or more, even more preferably 50% or more, and even more preferably 60% or more.

[0041] Although it is also possible to reduce the residual metal content in the block copolymer by reducing the amounts of polymerization initiator and hydrogenation catalyst added, reducing the amount of polymerization initiator increases the molecular weight of the block copolymer, and if the molecular weight falls outside the preferred range described above, the strength of the cured product tends to decrease. Furthermore, reducing the amount of hydrogenation catalyst during the hydrogenation reaction tends to increase the hydrogenation reaction time and temperature, resulting in a significant decrease in productivity.

[0042] Examples of methods for separating the solvent when recovering the block copolymer include a method in which a polar solvent that is a poor solvent for the block copolymer, such as acetone or alcohol, is added to the reaction solution after hydrogenation to precipitate and recover the block 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 block copolymer; and a method in which the block copolymer solution is directly heated to distill off the solvent.

[0043] The hydrogenated block copolymer may contain various stabilizers such as phenol-based stabilizers, phosphorus-based stabilizers, sulfur-based stabilizers, and amine-based stabilizers.

[0044] The block copolymer of this embodiment may have a "polar group" to the extent that the low dielectric loss tangent and low dielectric constant are not impaired. Examples of the "polar group" include, but are not limited to, functional groups 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, and atomic groups containing at least one of these functional groups.

[0045] The "polar group" can be formed using a modifying agent. 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.

[0046] The method for forming the "polar group" in the block copolymer of this embodiment can be any known method, and is not particularly limited. Examples of such methods include a melt-kneading method, a method in which each component is dissolved or dispersed in a solvent or the like and then reacted, etc. Other examples include a method of polymerizing by anionic living polymerization using a polymerization initiator having a functional group or an unsaturated monomer having a functional group, a method of modifying by addition reaction of a modifier that forms or contains a functional group at the living end, and a method of reacting a block copolymer with an organic alkali metal compound such as an organolithium compound (metalation reaction) and then adding a modifier that has a functional group to the block polymer to which the organic alkali metal has been added.

[0047] [Resin composition] The resin composition of this embodiment contains the block copolymer of this embodiment (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): Polar resin (excluding component (I)) Component (IV): Hardener (excluding component (II))

[0048] From the viewpoint of achieving a low dielectric constant, a low dielectric loss tangent, and flexibility of the resin composition of this embodiment and a cured product thereof, the resin composition of this embodiment preferably contains component (I): the block copolymer; and component (II): a radical initiator.

[0049] (Component (II): Radical initiator) As the radical initiator, any known radical initiator can be used. For example, thermal radical initiators include 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), and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne. Examples of the peroxides include dialkyl peroxides such as butyl peroxy-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.

[0050] (Component (III): Polar resin) The resin composition of this embodiment may contain component (III): a polar resin (excluding component (I)) from the viewpoint of imparting performance such as heat resistance and adhesiveness to a predetermined substrate, within a range that does not impair the low dielectric loss tangent and low dielectric constant of the cured product. By containing a polar resin, the resin composition of this embodiment tends to have excellent heat resistance. When component (III) is a polar resin having radical reactivity, the amount of the above-mentioned component (II): radical initiator can be appropriately adjusted depending on the reactivity, or component (II) can be omitted.

[0051] Examples of the radically reactive polar resin as component (III) include a polymer having at least one vinyl group in the polymer, a homopolymer of a compound containing a halogen element, and a copolymer of these with any compound, etc. From the viewpoint of reactivity, the radically reactive polar resin as component (III) is preferably a polymer having a vinyl group. The polymer having a vinyl group may be a polymer consisting of a repeating unit having a vinyl group, a polymer of a compound having a vinyl group and a compound having a polar group, or a polymer having a vinyl group obtained by reaction of the polar groups of a compound having a polar group. Examples of compounds having a vinyl group and a polar group include, but are not limited to, (meth)acrylic acid (in this specification, "(meth)acrylic" means methacrylic or acrylic), maleic acid, maleic acid monoalkyl ester, carboxyl group-containing vinyl monomers such as fumaric acid, vinyl sulfonic acid, (meth)allyl sulfonic acid, methyl vinyl sulfonic acid, styrene sulfonic acid, sulfone group-containing vinyl monomers such as vinyl sulfonic acid, (meth)allyl sulfonic acid, methyl vinyl sulfonic acid, styrene sulfonic acid, hydroxyl group-containing vinyl monomers such as hydroxystyrene, N-methylol (meth)acrylamide, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, phosphate group-containing vinyl monomers such as 2-hydroxyethyl (meth)acryloyl phosphate, phenyl-2-acryloyloxyethyl phosphate, 2-acryloyloxyethyl phosphonic acid, hydroxy Examples of the vinyl monomer include hydroxy group-containing vinyl monomers such as styrene, N-methylol (meth)acrylamide, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, polyethylene glycol (meth)acrylate, and 1-butene-3-ol; amino group-containing vinyl monomers such as aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and diethylaminoethyl (meth)acrylate; amide group-containing vinyl monomers such as (meth)acrylamide, N-methyl (meth)acrylamide, and N-butylacrylamide; nitrile group-containing vinyl monomers such as (meth)acrylonitrile, cyanostyrene, and cyanoacrylate; and epoxy group-containing vinyl monomers such as glycidyl methacrylate, tetrahydrofurfuryl (meth)acrylate, and p-vinylphenyl phenyloxide. Examples of compounds containing halogen elements include, but are not limited to, vinyl chloride, vinyl bromide, vinylidene chloride, allyl chloride, chlorostyrene, bromostyrene, dichlorostyrene, chloromethylstyrene, tetrafluorostyrene, and chloroprene.

[0052] (Component (IV): Curing agent) When the above-mentioned component (III) has low or no radical reactivity, from the viewpoint of reactivity, the resin composition of the present embodiment preferably contains component (IV): a curing agent. Component (IV): a curing agent generally has the function of reacting with component (III): a polar resin 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."

[0053] From the viewpoint of curing reactivity, it is preferable that component (IV): curing agent has two or more polar groups in one molecular chain that can react with the functional groups of component (III): polar resin. The component (IV) may be used alone or in combination of two or more. 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; Amino groups, carboxyl groups, carbonyl groups, hydroxyl groups, acid anhydride groups, sulfonic acid groups, and aldehyde groups; Isocyanate groups and hydroxyl, carboxylic, and phenolic hydroxyl groups; an anhydride group and a hydroxy group; silanol groups, hydroxyl groups, and carboxylic acid groups; Halogen groups, carboxylic acid groups, carboxylic acid ester groups, amino groups, phenol groups, and thiol groups; Alkoxy groups, hydroxy groups, alkoxide groups, and amino groups; Maleimide group and cyanate group etc. Whether the bond of these polar groups is component (III) or component (IV) can be selected arbitrarily.

[0054] 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 an epoxy group and component (IV) is a curing agent having an acid anhydride group, the reactivity between the epoxy group and the acid anhydride group is usually very low, but by adding a compound having an amino group as a curing accelerator, the epoxy group and the amino group 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 component (IV): the curing agent.

[0055] From the viewpoint of reactivity, the ratio of the amount of component (III): polar resin to the amount of component (IV): curing agent is preferably a molar ratio of polar groups of component (III): polar groups of component (IV) of 1:0.01 to 1:20, more preferably 1:0.05 to 1:15, and even more preferably 1:0.1 to 1:10.

[0056] Component (IV): Curing agent is a curing agent having an ester group, but is not limited to the following, and examples thereof include 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] Examples of curing agents having a carbodiimide group include, but are not limited to, V-03 and V-07 manufactured by Nisshinbo Chemical Inc.

[0061] 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. From the viewpoint of reactivity, the amino group is preferably a primary amine or a secondary amine, more preferably a primary amine.

[0062] 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.

[0063] 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.

[0064] When the resin composition of this embodiment contains the component (III), the polar resin (component (III)) is preferably at least one selected from the group consisting of epoxy resins, polyimide resins, polyphenylene ether resins, liquid crystal polyester resins, and fluorine-containing resins, from the viewpoints of the heat resistance and adhesiveness described above. More preferably, it is at least one selected from the group consisting of epoxy resins, polyimide resins, and polyphenylene ether resins.

[0065] From the viewpoint of heat resistance, the polyimide resin may be any resin that has an imide bond in the repeating unit and falls into the category of polyimide resins. For example, a typical polyimide structure obtained by polycondensation (imide bond) of a tetracarboxylic acid or its dianhydride with a diamine can be mentioned. From the viewpoint of curability, it is preferable that the polyimide structure has an unsaturated group at the end. Examples of polyimide resins having an unsaturated group at the end include, but are not limited to, maleimide polyimide resins, nadimide polyimide resins, and allylnadimide polyimide resins. The tetracarboxylic acid or its dianhydride is not limited to the following, but may be, for example, an aromatic tetracarboxylic acid dianhydride, an alicyclic tetracarboxylic acid dianhydride, an aliphatic tetracarboxylic acid dianhydride, etc. These may be used alone or in combination of two or more. The diamine is not limited to the following, but examples thereof include aromatic diamines, alicyclic diamines, aliphatic diamines, etc., which are commonly used in the synthesis of polyimides. These may be used alone or in combination of two or more. Furthermore, from the viewpoint of reducing the dielectric constant and the dielectric loss tangent of the resin composition and the cured product of the present embodiment, at least one of the tetracarboxylic acid, the dianhydride thereof, and the diamine may have one or more functional groups of at least one type selected from the group consisting of a fluorine group, a trifluoromethyl group, a hydroxyl group, a sulfone group, a carbonyl group, a heterocycle, a long-chain alkyl group, an allyl group, and the like.

[0066] Furthermore, as the polyimide resin, commercially available polyimide resins may be used, and examples thereof include, but are not limited to, Neoprim (registered trademark) C-3650 (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name), Neoprim C-3G30 (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name), Neoprim C-3450 (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name), Neoprim P500 (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name), BT (bismaleimide-triazine) resin (manufactured by Mitsubishi Gas Chemical Company, Inc.), JL-20 (manufactured by New Japan Chemical Company, Inc., trade name) (the varnishes of these polyimide resins may contain silica), and Rikacoat SN20 and Rikacoat PN2, both manufactured by New Japan Chemical Company, Inc. 0, Pyre-ML manufactured by IST, Upia-AT, Upia-ST, Upia-NF, Upia-LB manufactured by Ube Industries, Ltd., PIX-1400, PIX-3400, PI2525, PI2610, HD-3000, AS-2600 manufactured by Hitachi Chemical Co., Ltd., HPC-5000, HPC-5012, HPC-1000, HPC-5020, HPC-3010, HPC-6000, HPC-9000, HCI-7000, HCI-1000S, HCI-1200E, HCI-1300 manufactured by Showa Denko K.K., BMI-2300 manufactured by Daiwa Kasei Kogyo Co., Ltd., and MIR-3000 manufactured by Shin Nippon Kayaku Co., Ltd.

[0067] The polyphenylene ether resin, component (III), may be any resin that belongs to the category known as polyphenylene ether resin and contains phenylene ether units as repeating structural units, and may also contain other structural units in addition to phenylene ether units. In the homopolymer having a phenylene ether unit, the phenylene group in the phenylene unit may or may not have a substituent. Examples of the substituent include, but are not limited to, acrylic groups such as an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a tert-butyl group; cyclic alkyl groups such as a cyclohexyl group; vinyl groups, allyl groups, isopropenyl groups, 1-butenyl groups, 1-pentenyl groups, p-vinylphenyl groups, p-isopropenylphenyl groups, m-vinylphenyl groups, m-isopropenylphenyl groups, o-vinylphenyl groups, o-isopropenylphenyl groups, p-vinylbenzyl groups, p-isopropenylbenzyl groups, m-vinylbenzyl groups, m-isopropenylbenzyl groups, o-vinylbenzyl groups, o-isopropenylbenzyl groups, p-vinylphenylethenyl groups, p-vinylphenylpropenyl groups, p-vinylphenylbutenyl groups, m-vinylphenylethenyl groups, m-vinylphenylpropenyl groups, m-vinylphenylbutenyl groups, o-vinyl Examples of the functional group-containing substituent include an unsaturated bond-containing substituent such as an o-vinylphenylethenyl group, an o-vinylphenylpropenyl group, an o-vinylphenylbutenyl group, a methacryl group, an acryl group, a 2-ethylacryl group, or a 2-hydroxymethylacryl group; and a functional group-containing substituent such as 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, or a phenyltin group. From the viewpoint of curability, it is preferable that the compound has any polar group for the purpose of having radical reactivity and / or reactivity with the curing agent (IV).

[0068] From the viewpoint of the curability of the resin composition of the present embodiment, the polyphenylene ether resin as component (III) preferably has a molecular weight of 100,000 or less, more preferably 50,000 or less, and even more preferably 10,000 or less. The polyphenylene ether resin may have a linear structure or a crosslinked or branched structure.

[0069] The liquid crystal polyester resin of component (III) is a polyester that forms an anisotropic molten phase and may be any resin that falls into the category of liquid crystal polyester resins, including, but not limited to, Eastman Kodak's "X7G," Dartco's Xyday, Sumitomo Chemical's Econol, and Celanese's Vectra.

[0070] The fluorine-based resin as component (III) may be any resin that falls into the category of fluorine-based resins, and is an olefin polymer containing a fluorine group. Examples of the fluorine-based resin include, but are not limited to, polytetrafluoroethylene, perfluoroalkoxyalkane, ethylene-tetrafluoroethylene copolymer, perfluoroethylene-propene copolymer, polyvinylidene fluoride, polychlorotrifluoroethylene, and ethylene-chlorotrifluoroethylene copolymer.

[0071] 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.

[0072] In addition, 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, and from the viewpoint of reactivity, a carboxy group, an imidazole group, a hydroxyl group, a benzoxazine group, and a carbodiimide group are preferred, and from the viewpoint of dielectric performance, 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.

[0073] 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-type polyimide 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): a radical initiator and the above-mentioned component (IV): a curing agent from the viewpoint of curability.

[0074] Furthermore, when a polar resin having a high melting point and high rigidity is used as the polar resin (component (III)), the resin composition of this embodiment does not need to contain component (IV). Examples of the polar resin having a high melting point and high rigidity as component (III) include liquid crystal polyester resins and fluorine-based resins such as polytetrafluoroethylene. Since component (III) has a high melting point and high rigidity, the composition tends to have heat resistance and / or strength required for practical use even when component (IV) is not contained.

[0075] (Component (V): Additive) The resin composition of the present embodiment may further contain various additives such as a curing accelerator, a filler, and a flame retardant as component (V). Furthermore, the additives contained in the component (I) block copolymer are the same as those of the component (V) of the resin composition.

[0076] The curing accelerator is added to promote the reactivity between the above-mentioned components, and any conventionally known accelerator can be used, such as a phosphorus-based curing accelerator, an amine-based curing accelerator, an imidazole-based curing accelerator, a guanidine-based curing accelerator, or a metal-based curing accelerator. The curing accelerator may be used alone or in combination of two or more.

[0077] Examples of phosphorus-based curing accelerators include, but are not limited to, triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate, with triphenylphosphine and tetrabutylphosphonium decanoate being preferred.

[0078] Examples of the amine-based curing accelerator include, but are not limited to, trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene, with 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene being preferred.

[0079] Examples of the imidazole curing accelerator include, but are not limited to, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-phenylimidazole. Imidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazol-2-one 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2 Examples of imidazole compounds include 1-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline, as well as adducts of imidazole compounds with epoxy resins, and 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole are preferred. As the imidazole-based curing accelerator, a commercially available product may be used, and examples thereof include, but are not limited to, P200-H50 manufactured by Mitsubishi Chemical Corporation.

[0080] Examples of the guanidine curing accelerator include, but are not limited to, dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, and 7-methyl-1,5,7-trimethylguanidine. Examples include triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, and 1-(o-tolyl)biguanide, and dicyandiamide and 1,5,7-triazabicyclo[4.4.0]dec-5-ene are preferred.

[0081] Examples of metal-based curing accelerators include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Examples of organometallic complexes include, but are not limited to, organic cobalt complexes such as cobalt(II) acetylacetonate and cobalt(III) acetylacetonate, organic copper complexes such as copper(II) acetylacetonate, organic zinc complexes such as zinc(II) acetylacetonate, organic iron complexes such as iron(III) acetylacetonate, organic nickel complexes such as nickel(II) acetylacetonate, and organic manganese complexes such as manganese(II) acetylacetonate. Examples of organic metal salts include, but are not limited to, zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0082] Examples of fillers include, but are not limited to, inorganic fillers such as silica, calcium carbonate, magnesium carbonate, magnesium hydroxide, aluminum hydroxide, calcium sulfate, barium sulfate, carbon black, glass fiber, glass beads, glass balloons, glass flakes, graphite, titanium oxide, potassium titanate whiskers, carbon fiber, alumina, kaolin clay, silicic acid, calcium silicate, quartz, mica, talc, clay, zirconia, potassium titanate, alumina, and metal particles; and organic fillers such as wood chips, wood powder, pulp, and cellulose nanofibers. These may be used alone or in combination of two or more. The shape of these fillers is not particularly limited and may be any of scaly, spherical, granular, powdery, irregular, etc.

[0083] The resin composition or cured product of this embodiment is often exposed to high temperatures during molding, etc., and to prevent shrinkage due to the temperature change and deformation of the molded product, the filler preferably has a small linear expansion coefficient. From the viewpoint of reducing the linear expansion coefficient, silica is preferred as the filler, and examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica.

[0084] Examples of the flame retardant include halogen-based flame retardants such as bromine compounds, phosphorus-based flame retardants such as aromatic compounds, and flame retardants containing aromatic bromine compounds such as metal hydroxides, alkyl sulfonates, antimony trioxide, aluminum hydroxide, magnesium hydroxide, zinc borate, hexabromobenzene, decabromodiphenylethane, 4,4-dibromobiphenyl, and ethylenebistetrabromophthalimide. These flame retardants may be used singly or in combination of two or more. The above flame retardants also include so-called flame retardant assistants, which by themselves have a low flame retardancy effect but when used in combination with other flame retardants, exhibit a synergistically superior effect.

[0085] Fillers and flame retardants that have been previously surface-treated with a surface treatment agent such as a silane coupling agent can also be used. Examples of surface treatment agents include fluorine-containing silane coupling agents, aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, alkoxysilanes, organosilazane compounds, titanate coupling agents, etc. These may be used alone or in combination.

[0086] There are no particular restrictions on the other additives, so long as they are generally used in compounding resin compositions and cured products. Examples of other additives include, but are not limited to, pigments and / or colorants such as carbon black and titanium oxide; lubricants such as stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, and ethylene bisstearamide; mold release agents; plasticizers such as organic polysiloxanes, fatty acid esters such as phthalate esters, adipate compounds, and azelaate compounds, and mineral oil; antioxidants such as hindered phenols and phosphorus-based heat stabilizers; hindered amine light stabilizers; benzotriazole-based ultraviolet absorbers; antistatic agents; organic fillers; thickeners; antifoaming agents; leveling agents; resin additives such as adhesion promoters; other additives, or mixtures thereof.

[0087] From the viewpoint of reducing the dielectric constant and the dielectric loss tangent of the resin composition and the cured product of the present embodiment, it tends to be preferable that the resin composition of the present embodiment does not contain a pigment, a colorant, a lubricant, a release agent, or an antistatic agent.

[0088] 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 capable of dissolving them and stirring them (hereinafter referred to as "varnish"). However, varnish is preferred from the viewpoint of ease of handling. Examples of solvents include, but are not limited to, ketones such as acetone, methyl ethyl ketone (MEK), cyclohexanone, and γ-butyrolactone; acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, carbitol acetate, and diethyl glycol monoacerate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; and amide solvents such as dimethylformamide, dimethylacetamide (DMAc), and N-methylpyrrolidone. The organic solvents may be used alone or in combination of two or more.

[0089] [Cured product] The cured product of this embodiment contains the block copolymer of this embodiment described above. The cured product of the present embodiment is a cured product of the resin composition of the present embodiment, and is obtained by subjecting the resin composition to a curing reaction at any temperature and for any period of time. The concept encompasses not only a completely cured product, but also a form 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 drying and removing the solvent. The drying method may be 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. When carrying out the curing reaction after solvent removal, the resin composition is dried so that the amount of solvent in the resin composition is preferably 10% by mass or less, more preferably 5% by mass or less.

[0090] [Resin film] The resin film of the present embodiment is made of the resin composition of the present embodiment. The resin film of this embodiment can be obtained by spreading a varnish made of the resin composition of this embodiment onto a suitable support to form a uniform thin film, and then drying the varnish as described above to remove 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. Examples of the support include a film made of a plastic material, a metal foil, and release paper. Examples of films made of plastic materials that serve as supports include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polycarbonate, acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, and polyimides, with polyethylene terephthalate and polyethylene naphthalate being preferred from the standpoints of availability and cost. Examples of metal foils include copper foil and aluminum foil, with copper foil being preferred. As the copper foil, a foil made of a single metal, copper, or an alloy of copper and another metal (e.g., tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) may be used. The surface of the support that is to be bonded to the resin composition layer may be subjected to a matte treatment, a corona treatment, an antistatic treatment, or a release treatment.

[0091] [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 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, and then removing the solvent by the drying method described above. Examples of substrates include various glass cloths such as roving cloth, cloth, chopped mat, and surfacing mat; asbestos cloth, metal fiber cloth, and other synthetic or natural inorganic fiber cloths; woven or nonwoven fabrics obtained from liquid crystal fibers such as wholly aromatic polyamide fiber, wholly aromatic polyester fiber, and polybenzoxazole fiber; natural fiber cloths such as cotton cloth, linen cloth, and felt; natural cellulose-based substrates such as carbon fiber cloth, kraft paper, cotton paper, and cloth obtained from paper-glass blended fiber yarn; and polytetrafluoroethylene porous film. Of these, glass cloth is preferred from the viewpoint of low dielectric loss tangent and low dielectric constant. These substrates may be used singly or in combination of two or more. The proportion of solids in the prepreg made of the resin composition of this embodiment is preferably 30 to 80% by mass, more preferably 40 to 70% by mass. Having this proportion of 30% by mass or more tends to provide better insulation reliability when the prepreg is used for electronic substrates, etc. Having this proportion of 80% by mass or less tends to provide better mechanical properties, such as rigidity, when used for electronic substrates, etc.

[0092] [Laminate] The laminate of this embodiment includes the resin film and metal foil described above, and also includes the cured product of the prepreg described above and metal foil. The laminate of the present embodiment can be produced, for example, through a process including 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 thereby obtain a prepreg; step (b) of flattening the resin layer by heating and pressurizing it to obtain a cured prepreg; and step (c) of further forming a predetermined wiring layer made of a metal foil on the resin layer. In the step (a), the method for laminating the resin film on the substrate is not particularly limited, but examples thereof include lamination methods using a multi-stage press, a vacuum press, a normal pressure laminator, and a laminator that heats and presses under vacuum, and a method using a laminator that heats and presses under vacuum is preferred. By using this laminator, even if the target electronic circuit board has a fine wiring circuit on the surface, the resin can be embedded between the circuits without generating voids. In addition, lamination may be performed by a batch method or a continuous method using a roll or the like.

[0093] Examples of the substrate of the laminate described above include the substrates constituting the prepregs described above, as well as glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, polyphenylene ether substrates, fluororesin substrates, 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.

[0094] 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. 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 using 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.

[0095] 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.

[0096] [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 and curing the resin composition of the present embodiment or the prepreg of the present embodiment and a metal foil, and a portion of the metal foil is removed from the metal-clad laminate. 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.

[0097] Examples of metal foils 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 placed on one or both sides of the composite to form a laminate. Examples of the method for producing the 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 cured to obtain a laminate in which the cured prepreg and the metal foil are laminated together. One particularly preferred application of the 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 of this embodiment can be formed by a method of pressurizing and heat molding using the prepreg of this embodiment described above. The substrate can be the same as that described above for the prepreg. By including the resin composition of this embodiment, the printed wiring board has excellent strength and electrical properties (low dielectric constant and low dielectric loss tangent), and can suppress fluctuations in electrical properties due to environmental changes. It also has excellent insulation reliability and mechanical properties.

[0098] [Materials for electronic circuit boards] The material for an electronic circuit board of this embodiment includes a cured product of the resin composition of this embodiment. 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 includes at least one selected from the group consisting of a cured product of the resin composition described above, a resin film containing the resin composition of this embodiment or a cured product thereof, and a composite of a substrate and the resin composition, for example, a prepreg. The material for electronic circuit boards of this embodiment can be used as a printed wiring board having a resin-coated metal foil. [Example]

[0099] 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.

[0100] The methods for identifying the structure and measuring the physical properties of the block copolymer (component (I)) used in the following Examples and Comparative Examples are shown below.

[0101] [Methods for identifying polymer structure and measuring physical properties] ((1) Content of vinyl aromatic monomer units in block copolymers) The content of vinyl aromatic monomer units in the block copolymer before hydrogenation was measured using an ultraviolet spectrophotometer (Shimadzu Corporation, UV-2450).

[0102] ((2) Amount of vinyl bonds in block copolymer) The block copolymer before hydrogenation was measured using an infrared spectrophotometer (manufactured by JASCO Corporation, FT / IR-230). The vinyl bond content of the block copolymer was calculated by the Hampton method.

[0103] ((3) Molecular weight and molecular weight distribution of block copolymers) The molecular weight of the component (I) block copolymer before modification and before hydrogenation was measured by GPC [apparatus: LC-10 (Shimadzu Corporation), column: TSKgel GMHXL (4.6 mm x 30 cm)]. Tetrahydrofuran was used as the solvent. Measurement was performed at 35°C. The molecular weight is the weight average molecular weight calculated from the molecular weight of the peak in the chromatogram using a calibration curve (prepared using the peak molecular weight of the standard polystyrene) obtained 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). The molecular weight distribution is the ratio (Mw / Mn) of the obtained weight average molecular weight (Mw) to the number average molecular weight (Mn).

[0104] ((4) Hydrogenation rate of double bonds of conjugated diene monomer units of block copolymer) The hydrogenation rate of the double bonds of the conjugated diene monomer units was measured using the component (I) block copolymer after hydrogenation with a nuclear magnetic resonance spectrometer (manufactured by BRUKER, DPX-400).

[0105] [Block copolymer, resin composition material] (Preparation of hydrogenation catalyst) In the examples and comparative examples described later, the hydrogenation catalyst used in producing the block copolymer 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.

[0106] (Component (I) Block Copolymer) A block copolymer of a vinyl aromatic compound and a conjugated diene was prepared as follows. The structural values ​​of each block copolymer are shown in Tables 1 and 2. In the table, (A) indicates a polymer block (A) mainly composed of vinyl aromatic monomer units, (B) indicates a polymer block (B) mainly composed of conjugated diene monomer units, and (C) indicates a polymer block (C) composed of vinyl aromatic monomer units and conjugated diene monomer units.

[0107] <Block copolymer (1)> Batch polymerization was carried out using a tank-type reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 35 parts by mass of butadiene (concentration: 20% by mass) was added. Next, 0.65 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.8 mol of tetramethylethylenediamine (TMEDA) relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70° C. for 20 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 30 parts by mass of styrene was added and polymerization was carried out at 70° C. for 25 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 35 parts by mass of butadiene was added and polymerization was carried out for 20 minutes, after which methanol was added to terminate the polymerization reaction, thereby obtaining a block copolymer. The block copolymer (1) obtained as described above had a styrene content of 30% by mass and a weight-average molecular weight of 1.0×10 4 The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 70%.

[0108] <Block copolymer (2)> Batch polymerization was carried out using a tank-type reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 27.5 parts by mass of butadiene (concentration: 20% by mass) was added. Next, 0.65 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.8 mol of tetramethylethylenediamine (TMEDA) relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70° C. for 20 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 45 parts by mass of styrene was added and polymerization was carried out at 70° C. for 30 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 27.5 parts by mass of butadiene was added and polymerization was carried out for 20 minutes, after which methanol was added to terminate the polymerization reaction, thereby obtaining a block copolymer. The block copolymer (2) obtained as described above had a styrene content of 55% by mass and a weight-average molecular weight of 1.0×10 4 The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 71%.

[0109] <Block copolymer (3)> Batch polymerization was carried out using a tank-type reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 15 parts by mass of butadiene (concentration: 20% by mass) was added. Next, 0.65 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.8 mol of tetramethylethylenediamine (TMEDA) relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70° C. for 15 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 70 parts by mass of styrene was added and polymerization was carried out at 70° C. for 35 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 15 parts by mass of butadiene was added and polymerization was carried out for 15 minutes, after which methanol was added to terminate the polymerization reaction, thereby obtaining a block copolymer. The block copolymer (3) obtained as described above had a styrene content of 70% by mass and a weight-average molecular weight of 1.0×10 4 The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 69%.

[0110] <Block copolymer (4)> Batch polymerization was carried out using a tank-type reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 7.5 parts by mass of butadiene (concentration: 20% by mass) was added. Next, 0.65 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.8 mol of tetramethylethylenediamine (TMEDA) relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70° C. for 10 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 85 parts by mass of styrene was added and polymerization was carried out at 70° C. for 40 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 7.5 parts by mass of butadiene was added and polymerization was carried out for 10 minutes, after which methanol was added to terminate the polymerization reaction, thereby obtaining a block copolymer. The block copolymer (4) obtained as described above had a styrene content of 85% by mass and a weight-average molecular weight of 1.0×10 4 The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 70%.

[0111] <Block copolymer (5)> The polymerization reaction was carried out in the same manner as in the block copolymer (3), except that 0.5 mol of TMEDA was added per 1 mol of n-butyllithium. The block copolymer (5) obtained as described above had a styrene content of 70% by mass and a weight-average molecular weight of 1.0×10 4 The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 30%.

[0112] <Block copolymer (6)> The polymerization reaction was carried out in the same manner as in the block copolymer (3), except that 2 mol of TMEDA was added per 1 mol of n-butyllithium, the polymerization temperature was set to 50°C, and the polymerization time for each block was extended by 10 minutes. The block copolymer (6) obtained as described above had a styrene content of 70% by mass and a weight-average molecular weight of 1.0×10 4 The molecular weight distribution was 1.13, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 85%.

[0113] <Block copolymer (7)> A polymerization reaction was carried out in the same manner as in the block copolymer (3), except that 0.19 parts by mass of n-butyllithium was added relative to 100 parts by mass of the total monomers. The block copolymer (7) obtained as described above had a styrene content of 70% by mass and a weight-average molecular weight of 3.5×10 4 The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 71%.

[0114] <Block copolymer (8)> A polymerization reaction was carried out in the same manner as in the block copolymer (3), except that 0.34 parts by mass of n-butyllithium was added based on 100 parts by mass of the total monomers. The block copolymer (8) obtained as described above had a styrene content of 70% by mass and a weight-average molecular weight of 2.0×10 4The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 71%.

[0115] <Block copolymer (9)> A polymerization reaction was carried out in the same manner as in the block copolymer (3), except that 1.42 parts by mass of n-butyllithium was added based on 100 parts by mass of the total monomers. The block copolymer (8) obtained as described above had a styrene content of 70% by mass and a weight-average molecular weight of 0.5×10 4 The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 69%.

[0116] <Block copolymer (10)> The polymerization reaction was carried out in the same manner as in the case of the block copolymer (3). The resulting block copolymer was further added with the hydrogenation catalyst prepared as described above in an amount of 90 ppm (Ti basis) per 100 parts by mass of the block copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C for approximately 0.15 hours to obtain hydrogenated block copolymer (10). The resulting hydrogenated block copolymer (10) had a styrene content of 70% by mass and a weight-average molecular weight of 1.0×10 4 The molecular weight distribution was 1.10, the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 71%, and the hydrogenation rate was 21%.

[0117] <Block copolymer (11)> The same procedure as for block copolymer (10) was carried out, except that the hydrogenation reaction was carried out for about 0.5 hours. The resulting hydrogenated block copolymer (11) had a styrene content of 70% by mass and a weight-average molecular weight of 1.0×10 4The molecular weight distribution was 1.10, the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 70%, and the hydrogenation rate was 49%.

[0118] <Block copolymer (12)> The same procedure was followed as for block copolymer (10), except that the hydrogenation reaction was carried out for about 0.75 hours. The resulting hydrogenated block copolymer (12) had a styrene content of 70% by mass and a weight-average molecular weight of 1.0×10 4 The molecular weight distribution was 1.10, the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 71%, and the hydrogenation rate was 70%.

[0119] <Block copolymer (13)> Batch polymerization was carried out using a tank-type reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 30 parts by mass of butadiene (concentration: 20% by mass) was added. Next, 0.65 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.8 mol of tetramethylethylenediamine (TMEDA) relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70° C. for 20 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 70 parts by mass of styrene was added and polymerization was carried out at 70° C. for 35 minutes. Thereafter, methanol was added to terminate the polymerization reaction, thereby obtaining a block copolymer. The block copolymer (13) obtained as described above had a styrene content of 70% by mass and a weight-average molecular weight of 1.0×10 4 The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 70%.

[0120] <Block copolymer (14)> Batch polymerization was carried out using a tank-type reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 15 parts by mass of butadiene (concentration: 20% by mass) was added. Next, 0.65 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.8 mol of tetramethylethylenediamine (TMEDA) relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70° C. for 10 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 15 parts by mass of butadiene and 70 parts by mass of styrene was added and polymerized at 70° C. for 25 minutes. Thereafter, methanol was added to terminate the polymerization reaction, thereby obtaining a block copolymer. The block copolymer (14) obtained as described above had a styrene content of 70% by mass and a weight-average molecular weight of 1.0×10 4 The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / conjugated diene monomer units of polymer block (B)+polymer block (C)) was 70%.

[0121] <Block copolymer (15)> Batch polymerization was carried out using a tank-type reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 10 parts by mass of butadiene (concentration: 20% by mass) was added. Next, 0.65 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.8 mol of tetramethylethylenediamine (TMEDA) relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70° C. for 5 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 10 parts by mass of butadiene and 70 parts by mass of styrene was added and polymerization was carried out at 70° C. for 20 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 10 parts by mass of butadiene was added and polymerization was carried out at 70° C. for 5 minutes. Thereafter, methanol was added to terminate the polymerization reaction, thereby obtaining a block copolymer. The block copolymer (15) obtained as described above had a styrene content of 70% by mass and a weight-average molecular weight of 1.0×10 4 The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)+conjugated diene monomer units of polymer block (C)) was 71%.

[0122] <Block copolymer (16)> Batch polymerization was carried out using a tank-type reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 37.5 parts by mass of butadiene (concentration: 20% by mass) was added. Next, 0.65 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.8 mol of tetramethylethylenediamine (TMEDA) relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70° C. for 20 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 25 parts by mass of styrene was added and polymerization was carried out at 70° C. for 20 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 37.5 parts by mass of butadiene was added and polymerization was carried out for 20 minutes, after which methanol was added to terminate the polymerization reaction, thereby obtaining a block copolymer. The block copolymer (16) obtained as described above had a styrene content of 25% by mass and a weight-average molecular weight of 1.0×10 4 The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 70%.

[0123] <Block copolymer (17)> The same procedure as for the block copolymer (3) was carried out, except that 0.17 parts by mass of n-butyllithium was added relative to 100 parts by mass of the total monomers. The resulting block copolymer (17) had a styrene content of 70% by mass and a weight-average molecular weight of 4.0 × 10 4The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 71%.

[0124] <Block copolymer (18)> Batch polymerization was carried out using a tank-type reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 35 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.65 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.8 mol of tetramethylethylenediamine (TMEDA) relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70° C. for 20 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 25 parts by mass of butadiene was added and polymerization was carried out at 70° C. for 15 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 35 parts by mass of styrene was added and polymerization was carried out for 20 minutes, after which methanol was added to terminate the polymerization reaction, thereby obtaining a block copolymer. The block copolymer (18) obtained as described above had a styrene content of 70% by mass and a weight-average molecular weight of 1.0×10 4 The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 70%.

[0125] <Block copolymer (19)> Batch polymerization was carried out using a tank-type reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, styrene x A cyclohexane solution (concentration: 20% by mass) containing parts by mass was added. Next, 0.65 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.8 mol of tetramethylethylenediamine (TMEDA) relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70° C. for 30 minutes. Next, 30 parts by mass of butadiene and styrene (70-x) parts by massA cyclohexane solution (concentration: 20% by mass) containing the compound was added and polymerized for 15 minutes at 70° C. Methanol was then added to terminate the polymerization reaction, thereby obtaining a block copolymer. The block copolymer (19) obtained as described above had a styrene content of 70% by mass and a weight-average molecular weight of 1.0×10 4 The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / conjugated diene monomer units of polymer block (C)) was 70%.

[0126] <Block copolymer (20)> Batch polymerization was carried out using a tank-type reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution (concentration: 20% by mass) containing 70 parts by mass of styrene and 30 parts by mass of butadiene was added. Next, 0.65 parts by mass of n-butyllithium per 100 parts by mass of the total monomers and 0.8 mol of tetramethylethylenediamine (TMEDA) per 1 mol of n-butyllithium were added, and polymerization was carried out for 90 minutes at 70°C. Methanol was then added to terminate the polymerization reaction, yielding a block copolymer. The block copolymer (20) obtained as described above had a styrene content of 70% by mass and a weight-average molecular weight of 1.0×10 4 The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / conjugated diene monomer units of polymer block (C)) was 70%.

[0127] <Block copolymer (21)> Batch polymerization was carried out using a tank-type reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 15 parts by mass of butadiene (concentration: 20% by mass) was added. Next, 0.65 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.8 mol of tetramethylethylenediamine (TMEDA) relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70° C. for 15 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 15 parts by mass of butadiene and 50 parts by mass of styrene was added, and polymerization was carried out for 30 minutes. Next, a cyclohexane solution containing 20 parts by mass of styrene (concentration: 20% by mass) was added, and polymerization was carried out for 25 minutes. Thereafter, methanol was added to terminate the polymerization reaction, thereby obtaining a block copolymer. The block copolymer (21) obtained as described above had a styrene content of 70% by mass and a weight-average molecular weight of 1.0×10 4 The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / conjugated diene monomer units of polymer block (B)+polymer block (C)) was 70%.

[0128] <Block copolymer (22)> The same procedure as in the case of block copolymer (2) was carried out, except that n-butyllithium was used in an amount of 0.30 parts by mass per 100 parts by mass of the total monomers. The block copolymer (22) obtained as described above had a styrene content of 55% by mass and a weight-average molecular weight of 2.7×10 4 The molecular weight distribution was 1.10, and the content of units (a) derived from 1,2-bonds and / or 3,4-bonds (vinyl bond amount: units (a) / polymer block (B)) was 70%.

[0129] (Component (II): Radical initiator) Perbutyl C (NOF Corporation) Park Mill D (manufactured by NOF Corporation)

[0130] (Component (III): Polar resin) As a polar resin, polyphenylene ether resin (PPE) was polymerized as follows. A 1.5-liter jacketed reactor equipped with a sparger at the bottom for introducing oxygen-containing gas, stirring turbine blades and baffles, and a reflux condenser on the vent gas line at the top of the reactor was charged with 0.2512 g of cupric chloride dihydrate, 1.1062 g of 35% hydrochloric acid, 3.6179 g of di-n-butylamine, 9.5937 g of N,N,N',N'-tetramethylpropanediamine, 211.63 g of methanol, 493.80 g of n-butanol, and 180.0 g of 2,6-dimethylphenol containing 5 mol% 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane. The mass ratio of the solvent used was n-butanol:methanol = 70:30. Next, oxygen was introduced into the reactor via the sparger at a rate of 180 mL / min with vigorous stirring. At the same time, a heat transfer medium was passed through the jacket to maintain the polymerization temperature at 40 °C. The polymerization solution gradually took on the appearance of a slurry. When the polyphenylene ether reached the desired number-average molecular weight, the oxygen-containing gas was stopped being passed through, and the resulting polymerization mixture was heated to 50°C. Hydroquinone (a reagent manufactured by Wako Pure Chemical Industries, Ltd.) was then added in small amounts, and the mixture was kept at 50°C until the slurry-like polyphenylene ether turned white. 720 g of a methanol solution containing 6.5% by mass of 36% hydrochloric acid was then added, and the mixture was filtered and repeatedly washed with methanol to obtain wet polyphenylene ether. The mixture was then vacuum-dried at 100°C to obtain dry polyphenylene ether. The ηsp / c was 0.103 dL / g, and the yield was 97%. The ηsp / c was measured by preparing a 0.5 g / dl chloroform solution of the polyphenylene ether and determining the reduced viscosity (ηsp / c) at 30° C. using an Ubbelohde viscometer. The unit is dl / g. The resulting polyphenylene ether was modified as follows. 152.5 g of polyphenylene ether and 152.5 g of toluene were mixed and heated to approximately 85°C. 2.1 g of dimethylaminopyridine was then added. Once all solids had dissolved, 18.28 g of methacrylic anhydride was slowly added. The resulting solution was maintained at 85°C for 3 hours with continuous mixing. The solution was then cooled to room temperature to obtain a toluene solution of methacrylate-capped polyphenylene ether. 1000 mL of 10°C methanol was added dropwise to the resulting toluene solution in a 3 L cylindrical stainless steel vessel equipped with a homogenizer for stirring. The resulting powder was filtered, washed with methanol, and dried at 85°C under nitrogen for 18 hours.

[0131] <Component (IV): Crosslinking agent> Triallyl isocyanurate (TAIC TM ) (Mitsubishi Chemical Corporation)

[0132] [Method for measuring physical properties of resin composition] ((1) Dielectric loss tangent and dielectric constant) The dielectric loss tangent at 10 GHz was 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.

[0133] <Evaluation criteria for Examples 1 to 18 and Comparative Examples 1 to 7> Dielectric tangent ◎: 0.0025 or less ○: 0.0030 or less △: Less than 0.0035 ×: 0.0035 or more dielectric constant ◎: 2.53 or less ○: 2.55 or less △: Less than 2.60 ×:2.60 or more

[0134] <Evaluation criteria for Examples 19 to 30 and Comparative Examples 8 to 19> The evaluation was based on the difference in dielectric loss tangent and dielectric constant between Comparative Example 8, which does not contain a block copolymer, and each Example or Comparative Example (Comparative Example 8 - Example or Comparative Example). Dielectric tangent ◎: 0.0012 or more ○: 0.0010 or more, less than 0.0012 △: 0.00080 or more, less than 0.0010 ×: Less than 0.00080 (including equal and positive differences) dielectric constant ◎: 0.12 or more ○: 0.10 or more, less than 0.12 △: 0.08 or more, less than 0.10 ×: Less than 0.08 (including equal and positive differences)

[0135] <Evaluation criteria for Examples 31 to 51 and Comparative Examples 20 to 39> The evaluation was based on the difference in dielectric loss tangent and dielectric constant between Comparative Example 20, which does not contain a block copolymer, and each Example or Comparative Example (Comparative Example 20 - Example or Comparative Example). Dielectric tangent ◎: 0.010 or more ○: 0.008 or more, less than 0.010 △: 0.005 or more, less than 0.008 ×: Less than 0.005 (including equal and positive differences) dielectric constant ◎: 0.4 or more ○: 0.3 or more, less than 0.4 △: 0.2 or more, less than 0.3 ×: Less than 0.2 (including equal and positive differences)

[0136] <Evaluation criteria for Examples 52 to 66 and Comparative Examples 40 to 57> The evaluation was based on the difference in dielectric loss tangent and dielectric constant between Comparative Example 40, which does not contain a block copolymer, and each Example or Comparative Example (Comparative Example 40 - Example or Comparative Example). Dielectric tangent ◎: 0.0012 or more ○: 0.0010 or more, less than 0.0012 △: 0.00080 or more, less than 0.0010 ×: Less than 0.00080 (including equal and positive differences) dielectric constant ◎: 0.15 or more ○: 0.12 or more, less than 0.15 △: 0.10 or more, less than 0.12 ×: Less than 0.10 (including equal and positive differences)

[0137] ((2) Strength (glass transition temperature: Tg)) The dynamic viscoelasticity of the resin compositions of the examples and comparative examples described below was measured, and the temperature at which tan δ was maximized was determined as the glass transition temperature (Tg). A high Tg indicates high strength over a wide temperature range. The measurement was performed using an ARES (trade name, manufactured by TA Instruments) in a tensile mode. A test piece measuring 35 mm in length, approximately 12.5 mm in width, and 0.3 mm in thickness was cut out from the cured film described below, and this was used as the measurement sample. The measurements were carried out at a frequency of 10 rad / s and at temperatures ranging from -150 to 270°C.

[0138] (3) Heat resistance (change in glass transition temperature) Using the same equipment, specimen shape, and test conditions as in the above-mentioned Tg measurement, the measurement was carried out for two cycles, and the difference in Tg between the first and second cycles was calculated and evaluated. When the difference is large, it is evaluated as indicating that the curing reaction is insufficient, the strength is unsuitable for use at high temperatures in particular, and the heat resistance is low. The heat resistance was evaluated based on the difference in Tg (2nd cycle Tg - 1st cycle Tg) according to the following criteria. ◎: Below 3℃ ○: Below 5℃ △: 15℃ or less ×: Below 25℃

[0139] [Preparation of Resin Composition] (Examples 1 to 30), (Comparative Examples 1 to 19) Using the above-mentioned components, a resin composition was prepared by the following preparation method. The component ratios and physical properties are shown in Tables 3 to 6 below. First, each component was added to toluene (special grade product manufactured by Wako Pure Chemical Industries, Ltd., used as is), stirred and dissolved to prepare a varnish with a concentration of 20% by mass to 50% by mass. The varnish was applied to a release-treated Kapton film at a speed of 30 mm / sec, and then dried in a nitrogen stream at 100°C for 30 minutes to obtain a film. The obtained film was cured in a nitrogen stream at 200°C for 90 minutes to obtain a cured film. The cured film was used as an evaluation sample. Examples 1 to 30 and Comparative Examples 1 to 19 demonstrate that the block copolymer of the present invention, as a cured product, has an excellent balance of dielectric properties, strength, and heat resistance. It was found that the cured product is particularly suitable for glass cloth and printed wiring boards using metal laminates.

[0140] [Table 1]

[0141] [Table 2]

[0142] [Table 3]

[0143] [Table 4]

[0144] [Table 5]

[0145] [Table 6]

[0146] (Examples 31 to 51), (Comparative Examples 20 to 39) In addition to the above-mentioned components, the following components were further used to prepare resin compositions according to the following preparation method.

[0147] <Component (II): Radical initiator> Perbutyl P-90 (NOF Corporation)

[0148] <Component (III): Polar resin> Bisphenol A epoxy resin EXA-850CRP (DIC Corporation) Phenoxy resin YP-50S (Nippon Steel Chemicals)

[0149] <Component (IV): Hardener> 1-benzyl-2-phenylimidazole (Tokyo Chemical Industry Co., Ltd.) Phenol-based hardener KA-1163 (DIC Corporation)

[0150] The component ratios and physical properties are shown in Tables 7 to 10 below. First, all components except the phenol-based curing agent were added to toluene, stirred and dissolved to prepare a varnish with a concentration of 20% by mass to 50% by mass. When a phenolic curing agent was used, a 50% by mass solution of the phenolic curing agent was prepared using methyl ethyl ketone (a special grade product manufactured by Wako Pure Chemical Industries, Ltd.) as the solvent, and the solution was added to the varnish and stirred to prepare the varnish. The varnish was applied to a release-treated Kapton film at a speed of 30 mm / sec, and then dried in a nitrogen stream in a blower dryer at 100° C. for 30 minutes to obtain a film. The resulting film was subjected to a curing reaction in a nitrogen stream in a blower dryer at 200° C. for 90 minutes to obtain a cured film. The cured film was used as an evaluation sample.

[0151] [Table 7]

[0152] [Table 8]

[0153] [Table 9]

[0154] [Table 10]

[0155] (Examples 52 to 66), (Comparative Examples 40 to 57) In addition to the above-mentioned components, the following components were further used to prepare resin compositions according to the following preparation method.

[0156] <Component (III): Polar resin> [Polyimide resin] Bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (BMI-70) (K.I. Chemical Co., Ltd.) 4,4'-Bismaleimidodiphenylmethane (BMI-H) (K.I. Chemical Co., Ltd.)

[0157] <Component (IV): Hardener> Cyanate ester curing agent: 2,2-bis(4-cyanatephenyl)propane (Tokyo Chemical Industry Co., Ltd.) Diamine curing agent: 4,4'-diaminodiphenylmethane (Tokyo Chemical Industry Co., Ltd.)

[0158] The component ratios and physical properties are shown in Tables 11 to 13 below. First, a polar polyimide resin and a cyanate ester curing agent and / or a diamine curing agent were dissolved at 160°C in the blending ratios shown in Tables 11 to 13 below, and the mixture was allowed to react for 6 hours with stirring to obtain a bismaleimide-triazine resin oligomer. The obtained bismaleimide-triazine resin oligomer was dissolved in toluene, and the remaining components were added, stirred, and dissolved to prepare a varnish with a concentration of 20% to 50% by mass. The varnish was applied to a release-treated Kapton film at a speed of 30 mm / sec, and then dried in a nitrogen stream in a blower dryer at 100°C for 30 minutes to obtain a film. The film was subjected to a curing reaction in a nitrogen gas flow in a blower dryer at 200°C for a maximum of 90 minutes to obtain a cured film. The cured film was used as an evaluation sample. Examples 31 to 66 and Comparative Examples 20 to 57 demonstrate that the block copolymer of the present invention has an excellent balance of dielectric properties, strength, and heat resistance as a cured product, and is suitable for use in printed wiring boards using glass cloth and metal laminates.

[0159] [Table 11]

[0160] [Table 12]

[0161] [Table 13]

[0162] This application is based on a Japanese patent application (Patent Application No. 2022-033430) filed with the Japan Patent Office on March 4, 2022, and an international application (PCT / JP2023 / 000868) filed on January 13, 2023, the contents of which are incorporated herein by reference. [Industrial Applicability]

[0163] The block copolymer of the present invention, a resin composition containing the block copolymer, and a cured product thereof have industrial applicability as materials for films, prepregs, electronic circuit boards, and next-generation communication boards.

Claims

1. a polymer block (B) mainly composed of conjugated diene monomer units; A block copolymer having a polymer block (A) mainly composed of vinyl aromatic monomer units and / or a polymer block (C) composed of vinyl aromatic monomer units and conjugated diene monomer units, the conjugated diene monomer units of the polymer block (B) and the polymer block (C) in the block copolymer contain units (a) derived from a 1,2-bond and / or a 3,4-bond and units (b) derived from a 1,4-bond, and the content of the units (a) derived from a 1,2-bond and / or a 3,4-bond is 10 to 95% when the total content of the conjugated diene monomer units of the polymer block (B) and the polymer block (C) is taken as 100%, A block copolymer that satisfies the following conditions (i) to (iii): <Condition (i)> The weight average molecular weight of the block copolymer is 35,000 or less. <Condition (ii)> The content of vinyl aromatic monomer units in the block copolymer is 30% by mass or more. <Condition (iii)> The polymer block (B) is present in an amount of 5 parts by mass or more relative to 100 parts by mass of the block copolymer and is located at the terminal of the block copolymer.

2. When the total content of conjugated diene monomer units in the polymer block (B) and the polymer block (C) in the block copolymer is taken as 100%, the content of the units (a) derived from the 1,2-bond and / or the 3,4-bond is 25 to 85%. The block copolymer of claim 1 .

3. Component (I): the block copolymer of claim 1; Contains at least one component selected from the group consisting of the following components (II) to (IV): Resin composition. Component (II): Radical initiator Component (III): Polar resin (excluding component (I)) Component (IV): Curing agent (excluding component (II))

4. The component (III) is At least one resin selected from the group consisting of epoxy resins, polyimide resins, polyphenylene ether resins, liquid crystal polyester resins, and fluorine-based resins; The resin composition according to claim 3.

5. A cured product comprising the block copolymer according to claim 1.

6. A cured product of the resin composition according to claim 3 or 4.

7. A resin film comprising the resin composition according to claim 3 or 4.

8. A substrate; A prepreg which is a composite with the resin composition according to claim 3 or 4.

9. The prepreg according to claim 8 , wherein the substrate is a glass cloth.

10. A laminate comprising the resin film according to claim 7 and a metal foil.

11. A cured product of the prepreg according to claim 8, a metal foil, A laminate having:

12. A material for electronic circuit boards, comprising the cured product according to claim 5 .

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