Block copolymer, resin composition, molded body, and method for producing resin composition

Abstract

To provide a block copolymer which enables production of a resin composition that has sufficient flowability at a temperature lower than a temperature to progress self polymerization reaction of an epoxy resin, has good solubility to a thermosetting resin, and is excellent in terms of workability, toughness, flexibility, low molding shrinkage property, and thermal stability.SOLUTION: A block copolymer (I) satisfies conditions (a) to (e). Condition (a): The block copolymer (I) contains at least one polymer block (A) mainly containing an aromatic vinyl monomer unit, and the content of the polymer block (A) is 10 mass% or more and 50 mass% or less. Condition (b): The block copolymer (I) contains a polymer block (B) mainly containing a conjugated diene monomer unit. Condition (c): The hydrogenation ratio of the conjugated diene monomer unit is 20% or more and 100% or less. Condition (d): The melt flow rate according to JIS K 7210 under the conditions of 230°C and a load of 2.16 kg is 100 to 300 g / 10 min. Condition (e): The value of a storage elastic modulus G' at 125°C in a viscoelasticity chart is less than 2.0×10-1 MPa.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a block copolymer, a resin composition, a molded article, and a method for producing a resin composition. [Background technology]

[0002] In recent years, autonomous driving has been attracting attention as a new direction in the automotive industry, while high-speed communication technology has been gaining attention in the communications industry. These trends have led to significant advances in semiconductor technology, making it extremely important to improve the performance and ensure the reliability of semiconductor devices.

[0003] Epoxy resins have excellent properties such as high insulation, heat resistance, mechanical strength, chemical resistance, adhesiveness, and moldability, and have therefore traditionally been used as encapsulating materials to protect semiconductor devices and reduce external influences. However, epoxy resins have a rigid molecular structure, which means that the cured epoxy resins are very brittle. To improve this brittleness and impart toughness, a technique has been published in which an elastomer material is blended into the epoxy resin. However, this technique relies on a process that uses organic solvents, which can have adverse effects on the environment, workability, and the quality of the final product.

[0004] As a technique for compounding an elastomer material with an epoxy resin, for example, a technique for improving toughness by blending an epoxy resin with an elastomer solution prepared by dissolving a styrene-based elastomer in an organic solvent has been disclosed (see, for example, Patent Document 1). However, this technique has problems such as the possibility of workers becoming poisoned by organic solvents and residual solvents remaining in the product, and does not meet the processing standards required in recent years.

[0005] In light of the above-mentioned background, there is a demand for a solvent-free toughening agent that can be mixed with epoxy resins. Thermoplastic elastomers are commonly used toughening agents, but when trying to mix such thermoplastic elastomers with epoxy resins without solvents, the heating temperature must be set to 150°C or higher. If the epoxy resin is processed for a long period of time under such temperature conditions, the epoxy resin itself will undergo a self-polymerization reaction, causing a sudden increase in viscosity and a loss of fluidity, which is a problem. Furthermore, toughening agents mixed into epoxy resins are required to have high fluidity. For example, in the semiconductor encapsulation process, the tablet-shaped epoxy encapsulant must be heated and melted below the temperature at which the curing reaction proceeds, and then encapsulated and cured by transfer molding. Therefore, if an epoxy resin composition modified with a toughening agent with poor fluidity is used, it will not fill the mold sufficiently, resulting in short shots (molding defects).

[0006] In view of the above-mentioned problems, hydrogenated block copolymers with high fluidity have been disclosed as toughening agents with good fluidity (see, for example, Patent Document 2). However, these hydrogenated block copolymers do not melt sufficiently at temperatures below 150°C and must be processed at higher temperatures, which makes them unsuitable for use as toughening agents for epoxy resins. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2022 / 102505 [Patent Document 2] International Publication No. 2023 / 145369 Summary of the Invention [Problem to be solved by the invention]

[0008] As described above, the conventionally proposed techniques have a problem in that they have not yet provided a toughening agent that has sufficient fluidity below the temperature at which the self-polymerization reaction of an epoxy resin proceeds.

[0009] Therefore, an object of the present invention is to provide a block copolymer that has sufficient fluidity below the temperature at which the self-polymerization reaction of an epoxy resin proceeds, has good solubility in a thermosetting resin, and when formed into a resin composition with an epoxy resin, achieves excellent processability, toughness, flexibility, and low molding shrinkage, and also has excellent thermal stability even during a long-term heat-curing reaction. [Means for solving the problem]

[0010] As a result of extensive research into solving the problems of the prior art described above, the present inventors have found that the problems of the prior art described above can be solved by specifying a block copolymer having a specific structure, in which the content of a polymer block mainly composed of aromatic vinyl monomer units, the hydrogenation rate of conjugated diene monomer units, the melt flow rate (hereinafter sometimes referred to as MFR) under specific conditions, and the storage modulus under specific conditions, and have thus completed the present invention. That is, the present invention is as follows.

[0011] [1] A block copolymer (I) comprising an aromatic vinyl monomer unit and a conjugated diene monomer unit, A block copolymer (I) that satisfies the following conditions (a) to (e): (Condition (A)) It contains at least one polymer block (A) mainly composed of aromatic vinyl monomer units, and the content of the polymer block (A) is 10% by mass or more and 50% by mass or less. (Condition (b)) It contains a polymer block (B) mainly composed of conjugated diene monomer units. (Condition (C)) The hydrogenation rate of the conjugated diene monomer units is 20% or more and 100% or less. (Condition (2)) The melt flow rate is 100-300g / 10min under the conditions of JIS K7210, 230℃ and 2.16kg load. (Condition (e)) The storage modulus G' at 125°C on the viscoelasticity chart is 2.0 x 10 -1 It is less than MPa. [2] Contains at least one polymer block (C) consisting of an aromatic vinyl monomer unit and a conjugated diene monomer unit, the content of aromatic vinyl monomer units in the polymer block (C) is 5% by mass or more and 79% by mass or less of the total mass of the block copolymer (I); The block copolymer (I) described in [1] above. [3] The block copolymer (I) according to [1] or [2] above, wherein the vinyl bond content of the conjugated diene monomer units in the block copolymer (I) is 30% by mass or more. [4] The weight average molecular weight Mw is less than 70,000. The block copolymer (I) according to any one of [1] to [3] above. [5] The block copolymer (I) has, in the molecule, at least one polar group selected from the group consisting of an acid anhydride group, an amine group, a hydroxyl group, a carboxylic acid group, and an epoxy group. The block copolymer (I) according to any one of [1] to [4] above. [6] The hydrogenation rate of the conjugated diene monomer units is 50% or more and 100% or less. The block copolymer (I) according to any one of [1] to [5] above. [7] the content of the polymer block (A) mainly composed of aromatic vinyl monomer units in the block copolymer (I) is 15% by mass or more and 40% by mass or less; The block copolymer (I) according to any one of [1] to [6] above. [8] The block copolymer (I) according to any one of [1] to [7] above, which has a melt flow rate of 150 to 300 g / 10 min under the conditions of 230° C. and a load of 2.16 kg according to JIS K7210. [9] The block copolymer (I) according to any one of [1] to [8] above, a thermosetting resin (II); Contains the content of the block copolymer (I) is 1% by mass or more and 30% by mass or less, A resin composition having a content of the thermosetting resin (II) of 70% by mass or more and 99% by mass or less.

[10] The resin composition according to [9] above, wherein the thermosetting resin (II) is an epoxy resin, and the softening point of the epoxy resin is 50°C or higher and 120°C or lower.

[11] The resin composition according to

[10] above, wherein the epoxy resin is at least one epoxy resin selected from the group consisting of naphthalene-type, cresol novolac-type, and dicyclopentadiene-type epoxy resins.

[12] Further containing a phenolic curing agent (III) and a curing accelerator (IV), the content of the block copolymer (I) is 1% by mass or more and 10% by mass or less, The content of the thermosetting resin (II) is 70% by mass or more and 80% by mass or less, The content of the phenol-based curing agent (III) is 10% by mass or more and 30% by mass or less, The content of the curing accelerator (IV) is 0.1% by mass or more and 5% by mass or less. The resin composition according to any one of [9] to

[11] above.

[13] A molded article of the resin composition according to any one of [9] to

[12] above.

[14] The molded article according to

[13] above, which is a semiconductor encapsulation material.

[15] A method for producing the resin composition according to any one of [9] to

[12] above, The method includes a step of mixing the block copolymer (I) and the thermosetting resin (II) without using a solvent. A method for producing a resin composition. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a block copolymer which has sufficient fluidity below the temperature at which the self-polymerization reaction of an epoxy resin proceeds, has good solubility in a thermosetting resin, and when formed into a resin composition with an epoxy resin, achieves excellent processability, toughness, flexibility, and low molding shrinkage, and also has excellent thermal stability even during a long-term heat-curing reaction. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. Note that the following present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content, and the present invention can be carried out in various modified forms within the scope of its gist.

[0014] [Block copolymer] The block copolymer of this embodiment (hereinafter, may be referred to as block copolymer (I) or hydrogenated block copolymer (I)) is a block copolymer containing aromatic vinyl monomer units and conjugated diene monomer units, and satisfies the following conditions (A) to (E): (Condition (A)) It contains at least one polymer block (A) mainly composed of aromatic vinyl monomer units, and the content of the polymer block (A) is 10% by mass or more and 50% by mass or less. (Condition (b)) It contains a polymer block (B) mainly composed of conjugated diene monomer units. (Condition (C)) The hydrogenation rate of the conjugated diene monomer units is 20% or more and 100% or less. (Condition (2)) The melt flow rate (MFR) is 100-300g / 10min under the conditions of JIS K7210, temperature 230℃, and load of 2.16kg. (Condition (e)) The storage modulus G' at 125°C on the viscoelasticity chart is 2.0 x 10 -1 It is less than MPa.

[0015] According to the above-mentioned configuration, it is possible to provide a block copolymer which has sufficient fluidity below the temperature at which the self-polymerization reaction of the epoxy resin proceeds, has good solubility in the epoxy resin, and when formed into a resin composition with the epoxy resin, realizes excellent processability, toughness, flexibility, and low molding shrinkage, and has excellent thermal stability even during a long-term heat-curing reaction.

[0016] In this specification, the state before being incorporated into a polymer is referred to as a "compound", and the state after being incorporated into a polymer is referred to as a "monomer unit".

[0017] (aromatic vinyl monomer unit) The block copolymer (I) of this embodiment contains vinyl aromatic monomer units. Examples of aromatic vinyl compounds that form aromatic vinyl monomer units include, but are not limited to, monomer units derived from styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylethylene, N,N-dimethyl-p-aminoethylstyrene, and N,N-diethyl-p-aminoethylstyrene. In particular, styrene is preferred from the viewpoint of the balance between cost and the mechanical strength of the resin composition containing the block copolymer. These may be used alone or in combination of two or more.

[0018] (Total aromatic vinyl monomer unit content) The block copolymer (I) of the present embodiment preferably has a total aromatic vinyl monomer unit content of 10% by mass or more and 80% by mass or less, more preferably 20% by mass or more and 70% by mass or less, and even more preferably 30% by mass or more and 65% by mass or less. When the content of all aromatic vinyl monomer units is 10% by mass or more, the block copolymer (I) of this embodiment tends to have good tensile strength. By adopting such an embodiment, it becomes possible to increase the tensile strength of the epoxy resin composition using the block copolymer (I) of this embodiment, and a semiconductor encapsulant with high strength against external stress tends to be obtained. The total content of vinyl aromatic monomer units in the block copolymer (I) of the present embodiment can be measured using an ultraviolet spectrophotometer with the block copolymer before and after hydrogenation as samples. The total content of aromatic vinyl monomer units in the block copolymer (I) can be controlled within the above-mentioned range by mainly adjusting the amount of aromatic vinyl compound added to the polymerization reactor, the reaction temperature, and the reaction time.

[0019] (conjugated diene monomer units) The block copolymer (I) of this embodiment contains conjugated diene monomer units. A conjugated diene monomer unit is a monomer unit derived from a diolefin having a pair of conjugated double bonds. Examples of such diolefins 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, and 1,3-hexadiene. In particular, 1,3-butadiene and isoprene are preferred from the viewpoint of a good balance between molding processability and mechanical strength of the resin composition of this embodiment. These may be used alone or in combination of two or more.

[0020] (Polymer block (A) mainly composed of aromatic vinyl monomer units) The block copolymer (I) of this embodiment contains at least one polymer block (A) mainly composed of aromatic vinyl monomer units, which improves the tensile strength of the block copolymer (I). The phrase "mainly composed of aromatic vinyl monomer units" means that the polymer block (A) contains aromatic vinyl monomer units in an amount of 85% by mass or more, preferably 90% by mass or more, and more preferably 95% by mass or more. The polymer block (C) described below has an aromatic vinyl monomer unit content of 5% by mass or more and 79% by mass or less, and therefore the polymer block (A) and the polymer block (C) can be clearly distinguished from each other. Furthermore, the block copolymer (I) of this embodiment has a polymer block (A) content of 10% by mass or more and 50% by mass or less, preferably 15% by mass or more and 40% by mass or less, and more preferably 20% by mass or more and 30% by mass or less. When the content of the polymer block (A) mainly composed of aromatic vinyl monomer units is 10% by mass or more, the tensile strength of the block copolymer (I) is improved, and the tensile strength of the resin composition of the present embodiment containing the block copolymer (I) can be increased. This tends to result in a semiconductor encapsulant with high strength against external stress, and the resin composition of the present embodiment, which will be described later, tends to exhibit good heat resistance. Furthermore, if the content of the polymer block (A) is 50% by mass or less, the hardness of the block copolymer (I) increases, and the effect of imparting flexibility to the epoxy resin tends to decrease. 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 and after hydrogenation as a sample. The content of the polymer block (A) in the block copolymer (I) can be controlled within the above-mentioned range mainly by adjusting the amount of the aromatic vinyl compound added to the polymerization reactor, the reaction temperature, and the reaction time.

[0021] (Polymer block (B) mainly composed of conjugated diene monomer units) The block copolymer (I) of this embodiment contains at least one polymer block (B) mainly composed of conjugated diene monomer units. The phrase "mainly composed of conjugated diene monomer units" means that the polymer block (B) contains conjugated diene monomer units in an amount of 85% by mass or more, preferably 90% by mass or more, and more preferably 95% by mass or more. In the block copolymer (I) of the present embodiment, the content of the polymer block (B) is not particularly limited, but is preferably from 3% by mass to 90% by mass, more preferably from 10% by mass to 80% by mass, and even more preferably from 15% by mass to 70% by mass. By including the polymer block (B) in the block copolymer (I) of this embodiment, the resin composition of this embodiment, which will be described later, tends to have excellent flexibility and exhibit good elongation and impact resistance. In particular, when the content of the polymer block (B) in the block copolymer (I) of this embodiment is 15% by mass or more, a resin composition with even better flexibility tends to be obtained. The polymer block (B) may be formed at the end of the block copolymer (I) of this embodiment. Forming the polymer block (B) at the end of the block copolymer (I) tends to increase the melt flow rate of the block copolymer (I). Providing the polymer block (B) at the molecular end reduces the cohesive force between the polymer blocks (A) primarily composed of aromatic vinyl monomer units, and the melt flow rate of the block copolymer (I) tends to be high. A block copolymer (I) having such a high melt flow rate tends to melt at lower temperatures when melt-kneaded with an epoxy resin, resulting in good processability. Furthermore, adding the block copolymer (I) of this embodiment to an epoxy resin tends to suppress an increase in the melt viscosity of the epoxy resin composition. The content of the polymer block (B) in the block copolymer (I) can be controlled within the above-mentioned range by adjusting the amount of conjugated diene added to the polymerization reactor, the reaction temperature, and the like.

[0022] (Hydrogenation rate of double bonds of conjugated diene monomer units in block copolymer (I)) The hydrogenation rate of the double bonds of the conjugated diene monomer units in the block copolymer (I) of this embodiment is 20% or more and 100% or less, preferably 50% or more, more preferably 80% or more, and even more preferably 95% or more, from the viewpoint of obtaining good thermal oxidative degradation resistance in the production of the resin composition of this embodiment described later. The hydrogenation rate of the double bonds of the conjugated diene monomer units in the block copolymer (I) can be controlled within the above-mentioned range by adjusting the amount of hydrogenation. The hydrogenation rate of the block copolymer (I) can be measured using a nuclear magnetic resonance (NMR) spectrometer or the like.

[0023] (Hydrogenation rate of aromatic double bonds of aromatic vinyl monomer units in block copolymer (I)) The hydrogenation rate of the aromatic double bonds of the aromatic vinyl monomer units in the block copolymer (I) of this embodiment is not particularly limited, but from the viewpoint of not reducing compatibility with epoxy resins, it is preferably 50% or less, more preferably 30% or less, and even more preferably 10% or less. Although the ring hydrogenation of the aromatic double bonds of the aromatic vinyl monomer units improves the heat resistance temperature of the block copolymer itself, it also reduces polarity and reduces compatibility with epoxy resins, so it is preferable to keep it within the above numerical range. The hydrogenation rate of the aromatic double bond of the aromatic vinyl monomer unit in the block copolymer (I) can be measured using a nuclear magnetic resonance (NMR) spectrometer or the like.

[0024] (MFR of block copolymer (I)) The block copolymer (I) of the present embodiment has an MFR, measured according to JIS K7210 at a temperature of 230°C under a load of 2.16 kg, of 100 g / 10 min or more and 300 g / 10 min or less, preferably 150 g / 10 min or more and 300 g / 10 min or less, more preferably 200 g / 10 min or more and 300 g / 10 min or less, and even more preferably 250 g / 10 min or more and 300 g / 10 min or less. When the block copolymer (I) of this embodiment has an MFR of 100 g / 10 min or more, it becomes possible to produce the epoxy resin composition described below without using an organic solvent, and the melt viscosity of the epoxy resin composition tends to be reduced, improving processability. Furthermore, production of an epoxy resin composition without using an organic solvent can avoid deterioration of mechanical properties due to residual solvent in the product, and contributes to reducing the burden on workers and the environmental load. The upper limit of the MFR of the hydrogenated block copolymer (I) of this embodiment is 300 g / 10 min or less from the viewpoint of finishability, which will be described later. The MFR of the block copolymer (I) of the present embodiment can be controlled within the above-mentioned numerical range by adjusting the weight average molecular weight of the block copolymer (I), the content of the polymer block (A), the content of the polymer block (B), the content of the aromatic vinyl monomer unit in the copolymer block (C) described below, the amount of vinyl bonds in the conjugated diene monomer unit, and the hydrogenation rate of the double bonds of the conjugated diene monomer unit. For example, the MFR of the block copolymer (I) of this embodiment tends to be improved by decreasing the weight-average molecular weight of the block copolymer (I), decreasing the content of the polymer block (A), increasing the content of the polymer block (B), increasing the content of the aromatic vinyl monomer unit in the copolymer block (C) described below, increasing the content of the polymer block (B) in the terminal block, decreasing the content of the polymer block (B) in the internal block, increasing the amount of vinyl bonds in the conjugated diene monomer units, or decreasing the hydrogenation rate of the double bonds in the conjugated diene monomer units.

[0025] (Storage modulus in viscoelasticity measurement chart of block copolymer (I)) The block copolymer (I) of this embodiment has a storage modulus G' of 2.0 × 10 at 125°C in a viscoelasticity chart. -1 MPa, preferably less than 1.5 × 10 -1 MPa, more preferably less than 1.0 × 10 -1 MPa, more preferably less than 5.0 × 10 -2 MPa or less, and even more preferably 1.0 × 10 -2 MPa or less, and even more preferably 5.0 × 10 -3 MPa or less. G' is 2.0×10 -1 MPa or less, the processability during production of an epoxy resin composition using the block copolymer (I) of this embodiment tends to be improved. The lower limit of G' is 1.0 × 10 or less from the viewpoint of flexibility and toughness when formed into an epoxy resin composition. -6 MPa or more, preferably 1.0 × 10-5 MPa or more, more preferably 1.0 × 10 -4 MPa or more, and more preferably 1.5 × 10 -4 MPa or more. The value of the storage modulus G′ at 125° C. in the viscoelasticity measurement chart of the block copolymer (I) of this embodiment can be adjusted to fall within the above-mentioned range by adjusting the content of the polymer block (A), the vinyl bond amount of the polymer block (B), the arrangement of the polymer block (B), the vinyl bond amount of the polymer block (C), the hydrogenation rate, the weight-average molecular weight, etc. In the production process of the block copolymer (I), the content of the polymer block (A), the vinyl bond amount of the polymer block (B), the arrangement of the polymer block (B), the vinyl bond amount of the polymer block (C), the hydrogenation rate, and the weight-average molecular weight can be controlled by adjusting the amount of polymerization initiator added, the order of monomer supply, and the amount of hydrogen supplied during the hydrogenation process.

[0026] (Copolymer block (C)) The block copolymer (I) of this embodiment may contain a polymer block (C) composed of an aromatic vinyl monomer unit and a conjugated diene monomer unit. The content of aromatic vinyl monomer units in the polymer block (C) is preferably 5% by mass or more and 79% by mass or less, more preferably 10% by mass or more and 70% by mass or less, and even more preferably 15% by mass or more and 60% by mass or less, of the entire block copolymer (I). When the content of aromatic vinyl monomer units in the copolymer block (C) is 5% by mass or more of the entire block copolymer (I), the low-temperature side glass transition temperature (hereinafter also referred to as Tg) of the block copolymer (I) of this embodiment shifts to a higher temperature side. The shift in the low-temperature side glass transition temperature to a higher temperature side tends to reduce molding shrinkage of a molded article of the resin composition of this embodiment. Furthermore, by making the content equal to or greater than the above range, the entanglement conversion molecular weight becomes small due to intermolecular interactions, and a block copolymer (I) with high strength tends to be obtained. If the content of aromatic vinyl monomer units in polymer block (C) exceeds 79% by mass of the entire block copolymer (I), it becomes difficult to clearly distinguish it from polymer block (A) mainly composed of aromatic vinyl monomer units in block copolymer (I) of the present embodiment, and hardness tends to increase, which in turn tends to reduce flexibility of the epoxy resin composition containing it and make it difficult to obtain sufficient elongation at break. The content of the aromatic vinyl monomer unit in the polymer block (C) can be measured by a nuclear magnetic resonance (NMR) spectrometer or the like. The content of the aromatic vinyl monomer unit in the polymer block (C) can be controlled within the above-mentioned range by adjusting the amounts of the aromatic vinyl compound and conjugated diene added to the polymerization reactor, the reaction temperature, etc.

[0027] (Amount of vinyl bonds in polymer block (B) mainly composed of conjugated diene monomer units) In the polymer block (B) mainly composed of conjugated diene monomer units of the present embodiment, the vinyl bond content of the conjugated diene moiety in the polymer block before hydrogenation is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 45% by mass or more. By setting the value within the above range, the block copolymer (I) of this embodiment tends to exhibit higher flexibility and MFR value. When the block copolymer (I) has excellent flexibility and a high MFR value, blending the block copolymer (I) of this embodiment with an epoxy resin tends to impart high flexibility and reduce the melt viscosity of the epoxy resin composition. The upper limit of the vinyl bond content of the conjugated diene moiety in the polymer block (B) mainly composed of conjugated diene monomer units before hydrogenation is not particularly limited, but is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. By setting the value within the above range, a block copolymer (I) having excellent thermal stability tends to be obtained. The vinyl bond amount of the conjugated diene moiety in the polymer block (B) mainly composed of conjugated diene monomer units before hydrogenation can be controlled by using a regulator such as a tertiary amine compound or an ether compound described below. When 1,3-butadiene is used as the conjugated diene, from the viewpoint of obtaining good impact resistance in the resin composition of this embodiment described below, the amount of 1,2-vinyl bonds in the conjugated diene portion in the polymer block (B) before hydrogenation of the polymer block (B) is preferably 30% by mass or more and 95% by mass or less, more preferably 35% by mass or more and 90% by mass or less, and even more preferably 40% by mass or more and 90% by mass or less. When isoprene is used as the conjugated diene, or when 1,3-butadiene and isoprene are used in combination, the total amount of 1,2-vinyl bonds and 3,4-vinyl bonds is preferably 3% by mass or more and 75% by mass or less, and more preferably 5% by mass or more and 60% by mass or less. In this embodiment, the total amount of 1,2-vinyl bonds and 3,4-vinyl bonds (however, when 1,3-butadiene is used as the conjugated diene, the amount of 1,2-vinyl bonds) is referred to as the amount of vinyl bonds. The vinyl bond content can be measured by measuring the copolymer before hydrogenation as a sample with an infrared spectrophotometer (for example, by the Hampton method).

[0028] (Vinyl bond content of copolymer block (C) consisting of aromatic vinyl monomer units and conjugated diene monomer units) The vinyl bond content of the conjugated diene portion in the polymer block of the copolymer block (C) consisting of aromatic vinyl monomer units and conjugated diene monomer units before hydrogenation is preferably 25% by mass or more, more preferably 30% by mass or more, and even more preferably 35% by mass or more. By setting the value within the above range, the block copolymer (I) of this embodiment tends to exhibit higher flexibility and MFR value. The excellent flexibility and high MFR value of the block copolymer (I) imparts flexibility when blended with an epoxy resin, and makes it possible to reduce the melt viscosity of an epoxy resin composition using the block copolymer (I) of this embodiment. The upper limit of the vinyl bond content of the conjugated diene moiety in the polymer block (C)) composed of aromatic vinyl monomer units and conjugated diene monomer units before hydrogenation is not particularly limited, but is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. By keeping it within the above numerical range, a block copolymer with better thermal stability tends to be obtained. The vinyl bond amount of the conjugated diene moiety in the polymer block (C) composed of aromatic vinyl monomer units and conjugated diene monomer units before hydrogenation can be controlled by using a regulator such as a tertiary amine compound or an ether compound described below. When 1,3-butadiene is used as the conjugated diene, from the viewpoint of obtaining good impact resistance in the resin composition of the present embodiment described below, the 1,2-vinyl bond content of the conjugated diene portion in the polymer block of polymer block (C) before hydrogenation is preferably 30% by mass or more and 95% by mass or less, more preferably 35% by mass or more and 90% by mass or less, and even more preferably 40% by mass or more and 90% by mass or less. When isoprene is used as the conjugated diene, or when 1,3-butadiene and isoprene are used in combination, the total amount of 1,2-vinyl bonds and 3,4-vinyl bonds is preferably 3% by mass or more and 75% by mass or less, and more preferably 5% by mass or more and 60% by mass or less. In this embodiment, the total amount of 1,2-vinyl bonds and 3,4-vinyl bonds (however, when 1,3-butadiene is used as the conjugated diene, the amount of 1,2-vinyl bonds) is referred to as the amount of vinyl bonds. The vinyl bond content can be measured by measuring the copolymer before hydrogenation as a sample with an infrared spectrophotometer (for example, by the Hampton method).

[0029] (Amount of vinyl bond in conjugated diene monomer unit) In the block copolymer (I) of this embodiment, the amount of vinyl bonds in all conjugated diene monomer units is preferably 30% by mass or more, more preferably 35% by mass or more, and even more preferably 40% by mass or more. When the vinyl bond content in all conjugated diene monomer units of the block copolymer (I) is 30% by mass or more, precipitation from the solution due to crystallization of the hydrogenated conjugated diene block can be suppressed in the hydrogenation step described below. Furthermore, by controlling the amount of vinyl bonds in all conjugated diene monomer units of the block copolymer (I) within the above numerical range, it tends to be possible to achieve a high MFR value. The amount of vinyl bonds in each block will be described in detail below. The vinyl bond content in all conjugated diene monomer units of the block copolymer (I) of this embodiment can be controlled within the above numerical range by using a regulator such as a tertiary amine compound or an ether compound described below.

[0030] (Weight-average molecular weight of block copolymer (I)) The block copolymer (I) of this embodiment preferably has a weight average molecular weight (Mw) of less than 70,000, more preferably less than 60,000, and even more preferably less than 50,000. When the weight-average molecular weight Mw of the block copolymer (I) of the present embodiment is within the above-mentioned numerical range, a block copolymer (I) satisfying the above-mentioned MFR value can be obtained, and the processability of the epoxy resin composition obtained by mixing the block copolymer (I) with an epoxy resin is improved, which tends to reduce the burden on the production process of the epoxy resin composition. If the weight average molecular weight (Mw) is 70,000 or more, it will not melt sufficiently at the temperature at which it is mixed with an epoxy resin to produce an epoxy resin composition, and processing will tend to become difficult. The lower limit of the weight-average molecular weight (Mw) of the block copolymer (I) of this embodiment is not particularly limited, but from the viewpoints of extrudability during pellet production of the block copolymer (I) of this embodiment and obtaining good mechanical strength in an epoxy resin composition mixed with an epoxy resin, the weight-average molecular weight (Mw) is preferably 10,000 or more, more preferably 20,000 or more, even more preferably 30,000 or more, and even more preferably 35,000 or more. When the weight-average molecular weight (Mw) is 10,000 or more, the epoxy resin composition tends to exhibit good mechanical strength. The weight average molecular weight of the block copolymer (I) of the present embodiment is determined by measuring it by gel permeation chromatography (GPC) and using a calibration curve (prepared using the peak molecular weight of the standard polystyrene) obtained from the measurement of a commercially available standard polystyrene.

[0031] (Molecular weight distribution (Mw / Mn) of block copolymer (I)) The molecular weight distribution (Mw / Mn) of the block copolymer (I) of the present embodiment is not particularly limited, but from the viewpoint of shear stability, it is preferably 10 or less, more preferably 1 to 8, and even more preferably 1.01 to 1.10. The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the block copolymer (I) are measured by gel permeation chromatography (GPC), and the molecular weight of the peak in the chromatogram is determined using a calibration curve (constructed using the peak molecular weight of the standard polystyrene) obtained from measurements of commercially available standard polystyrene. The molecular weight distribution (Mw / Mn) of the block copolymer (I) is determined from the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn).

[0032] (Structure of Block Copolymer (I)) The structure of the block copolymer (I) of this embodiment is not particularly limited, but examples thereof include those having a structure represented by the following general formula: (bc) n , c-(bc) n , b-(cb) n , (bc) m -X, (cb) m-X, c-(ba) n , c-(ab) n , c-(aba) n , c-(bab) n , c-(bca) n , a-(cbca) n , ac-(ba) n , ac-(ab) n , ac-(ba) n -b, ca-(ba) n -c, ac-(ba) n -c, ab-(ca) n -b, ac-(bc) n -ac, c-(abc) n -ac, a-(cb) n -ca, c-(ac) n -bcac, [(abc) n ] m -X, [a-(bc) n ] m -X, [(ab) n -c] m -X, [(aba) n -c] m -X, [(bab) n -c] m -X, [(cba) n ] m -X, [c-(ba) n ] m -X, [c-(aba) n ] m -X, [c-(bab) n ] m -X In each of the above general formulas, a represents a polymer block (A) mainly composed of aromatic vinyl monomer units, b represents a polymer block (B) mainly composed of conjugated diene monomer units, and c represents a copolymer block (C) composed of aromatic vinyl monomer units and conjugated diene monomer units. 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.

[0033] (Polar Groups Contained in Block Copolymer (I)) The block copolymer (I) of this embodiment can be a modified block copolymer in which an atomic group having a predetermined polar group is bonded. The presence of a predetermined polar group in the block copolymer of this embodiment tends to improve the toughness of the epoxy resin composition when it is formed into the composition. This is because the polar group in the block copolymer (I) reacts with the ring-opening site of the oxirane ring in the epoxy resin, improving the adhesive strength at the interface between the epoxy resin matrix and the dispersed phase of the block copolymer (I), thereby achieving high toughness. The atomic group having a functional group is preferably bonded as a step prior to the hydrogenation step described below. The "atomic group having a functional group" is not limited to the following, but examples thereof include atomic groups containing at least one functional group selected from 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, a phenyltin group, etc. Particularly preferred are atomic groups containing at least one functional group selected from a hydroxyl group, an epoxy group, an amino group, a silanol group, and an alkoxysilane group. Among these, from the viewpoint of reactivity with epoxy resins, a hydroxyl group, an amino group, a carboxyl group, an acid anhydride group, and an epoxy group are more preferred. The "atomic group having a functional group" can be bonded by 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, and N-methylpyrrolidone.

[0034] (Crystallization peak of block copolymer (I)) The block copolymer (I) of the present embodiment is preferably a hydrogenated product in which a crystallization peak due to the copolymer block (C) is substantially absent in the range of −25 to 80° C. in a differential scanning calorimetry (DSC) chart. Here, "substantially no crystallization peak attributable to the copolymer block (C) is present in the range of -25 to 80°C" means that, in this temperature range, no peak attributable to the crystallization of the copolymer block (C) portion appears, or even if a peak attributable to crystallization is observed, the calorific value of the crystallization peak due to the crystallization is less than 3 J / g, preferably less than 2 J / g, more preferably less than 1 J / g, and even more preferably there is no crystallization peak calorific value. As described above, when there is substantially no crystallization peak attributable to the polymer block (C) in the range of −25 to 80° C., the block copolymer (I) of the present embodiment has good flexibility, and the resin composition of the present embodiment, which will be described later, is preferably softened. To obtain a block copolymer (I) in which a crystallization peak due to the polymer block (C) does not substantially exist in the range of −25 to 80° C., a copolymer obtained by carrying out a polymerization reaction under the conditions described below using a predetermined regulator for adjusting the vinyl bond amount and the copolymerizability between the aromatic vinyl compound and the conjugated diene may be subjected to a hydrogenation reaction.

[0035] (Tan δ (loss tangent) peak temperature in the viscoelasticity measurement chart of block copolymer (I)) In the block copolymer (I) of this embodiment, at least one tan δ (loss tangent) peak is preferably present in a viscoelasticity measurement chart between -25°C and 60°C, more preferably between -15°C and 50°C, and even more preferably between -5°C and 40°C. This tan δ peak is a peak attributable to polymer block (C) in block copolymer (I). The presence of at least one such peak in the temperature range of −25° C. to 60° C. is important for maintaining a low mold shrinkage rate in the resin composition of this embodiment, which will be described later. As described above, the polymer block (C) is obtained by hydrogenating a copolymer block comprising aromatic vinyl monomer units and conjugated diene monomer units. In the block copolymer (I) of this embodiment, in order to ensure that at least one peak of tanδ (loss tangent) exists in the range of −25° C. or higher and 60° C. or lower, it is effective to control the conjugated diene monomer unit / aromatic vinyl monomer unit (mass ratio), and the conjugated diene monomer unit / aromatic vinyl monomer unit (mass ratio) is preferably 79 / 21 to 30 / 70, more preferably 75 / 35 to 30 / 70, and even more preferably 70 / 30 to 30 / 70. To obtain a block copolymer (I) having at least one peak of tanδ (loss tangent) in the range of −25° C. to 60° C., a copolymer obtained by carrying out a polymerization reaction under the conditions described below using a predetermined regulator that adjusts the vinyl bond amount in the copolymer block (C), the content of aromatic vinyl monomer units in the polymer block (C), and the copolymerizability between the aromatic vinyl compound and the conjugated diene may be subjected to a hydrogenation reaction. The tan δ of the block copolymer (I) can be measured using a viscoelasticity measuring device (ARES, manufactured by TA Instruments Co., Ltd.) under conditions of a strain of 0.5%, a frequency of 1 Hz, and a temperature rise rate of 3°C / min. Specifically, it can be measured by the method described in the Examples below.

[0036] [Method for producing block copolymer (I)] The block copolymer (I) of the present embodiment can be obtained, for example, by subjecting an aromatic vinyl compound and a conjugated diene compound to living anionic polymerization in a hydrocarbon solvent using a polymerization initiator such as an organic alkali metal compound, followed by hydrogenation.

[0037] (hydrocarbon solvent) Examples of hydrocarbon solvents include, but are not limited to, aliphatic hydrocarbons such as n-butane, isobutane, n-pentane, n-hexane, n-heptane, and n-octane; alicyclic hydrocarbons such as cyclohexane, cycloheptane, and methylcycloheptane; and aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene.

[0038] (Polymerization initiator) The polymerization initiator is not particularly limited, but examples thereof include organic alkali metal compounds such as aliphatic hydrocarbon alkali metal compounds, aromatic hydrocarbon alkali metal compounds, and organic amino alkali metal compounds, which are known to have anionic polymerization activity for aromatic vinyl compounds and conjugated dienes. The organic alkali metal compound is not limited to the following, but for example, an aliphatic or aromatic hydrocarbon lithium compound having 1 to 20 carbon atoms is preferable, and compounds containing one lithium atom per molecule, dilithium compounds containing multiple lithium atoms per molecule, trilithium compounds, and tetralithium compounds can be used. Specific examples include n-propyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, n-pentyllithium, n-hexyllithium, benzyllithium, phenyllithium, tolyllithium, a reaction product of diisopropenylbenzene with sec-butyllithium, and a reaction product of divinylbenzene with sec-butyllithium and a small amount of 1,3-butadiene. Furthermore, for example, organic alkali metal compounds disclosed in US Pat. No. 5,708,092, British Patent No. 2,241,239, and US Pat. No. 5,527,753 can also be used.

[0039] (adjusting agent) When an aromatic vinyl compound and a conjugated diene are copolymerized using an organic alkali metal compound as a polymerization initiator, the content of vinyl bonds (1,2-bonds or 3,4-bonds) resulting from the conjugated diene incorporated into the polymer and the random copolymerizability of the aromatic vinyl compound and the conjugated diene can be adjusted by using a specific adjusting agent. Such regulators include, but are not limited to, tertiary amine compounds, ether compounds, metal alcoholate compounds, and the like. The adjuster may be used alone or in combination of two or more. Examples of tertiary amine compounds include, but are not limited to, compounds represented by the general formula: R1R2R3N (wherein R1, R2, and R3 represent a hydrocarbon group having 1 to 20 carbon atoms or a hydrocarbon group having a tertiary amino group). Specific examples include 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 ether compound is not limited to the following, but for example, a linear ether compound and a cyclic ether compound can be used. Examples of linear ether compounds include, but are not limited to, dialkyl ether compounds of ethylene glycol such as dimethyl ether, diethyl ether, diphenyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and ethylene glycol dibutyl ether; and dialkyl ether compounds of diethylene glycol such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol dibutyl ether. Examples of cyclic ether compounds include, but are not limited to, tetrahydrofuran, dioxane, 2,5-dimethyloxolane, 2,2,5,5-tetramethyloxolane, 2,2-bis(2-oxolanyl)propane, and alkyl ethers of furfuryl alcohol. Examples of metal alcoholate compounds include, but are not limited to, sodium t-pentoxide, sodium t-butoxide, potassium t-pentoxide, and potassium t-butoxide.

[0040] (Polymerization method) As a method for polymerizing an aromatic vinyl compound and a conjugated diene using an organic alkali metal compound as a polymerization initiator, a conventionally known method can be applied. Although not limited to the following, for example, batch polymerization, continuous polymerization, or a combination thereof may be used, with batch polymerization being particularly suitable for obtaining a copolymer with 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 allows the monomer and solvent to be maintained in a liquid phase within the above temperature range. Furthermore, it is preferable to take care to prevent impurities such as water, oxygen, carbon dioxide gas, etc. that may inactivate the catalyst and living polymer from being mixed into the polymerization system.

[0041] Furthermore, at the end of the polymerization step, a required amount of a bifunctional or higher functional coupling agent may be added to carry out a coupling reaction. The bifunctional coupling agent may be any known one and is not particularly limited. Examples thereof include 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, the polyfunctional coupling agent having three or more functionalities may be any known one, and is not particularly limited. For example, polyhydric or higher alcohols, epoxidized soybean oil, diglycidyl bisphenol A, 1,3-bis(N-N'-diglycidylaminomethyl)cyclohexane and other polyhydric epoxy compounds; n (wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 3 to 4), such as methylsilyl trichloride, t-butylsilyl trichloride, silicon tetrachloride, and bromides thereof; n (wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 3 to 4), for example, polyvalent halogen compounds such as methyltin trichloride, t-butyltin trichloride, and tin tetrachloride. Dimethyl carbonate, diethyl carbonate, etc. may also be used.

[0042] (Denaturation process) As described above, the block copolymer (I) of the present embodiment is a modified block copolymer to which an atomic group having a functional group is bonded. The atomic group having a functional group is preferably bonded as a step prior to the hydrogenation step described below. The "atomic group having a functional group" is not limited to the following, but examples thereof include atomic groups containing at least one functional group selected from a hydroxyl group, a carboxyl group, a carbonyl group, a thiocarbonyl group, an acid halide group, an acid anhydride group, a carboxylic acid group, a thiocarboxylic acid group, an aldehyde group, a thioaldehyde group, a carboxylic acid ester group, an amide group, a sulfonic acid group, a sulfonate ester group, a phosphoric acid group, a phosphoric acid ester group, an amino group, an imino group, a nitrile group, a pyridyl group, a quinoline group, an epoxy group, a thioepoxy group, a sulfide group, an isocyanate group, an isothiocyanate group, a silicon halide group, a silanol group, an alkoxy silicon group, a tin halide group, a boronic acid group, a boron-containing group, a boronate salt group, an alkoxy tin group, a phenyl tin group, etc. Particularly preferred are atomic groups containing at least one functional group selected from an acid anhydride group, a carboxyl group, a hydroxyl group, an epoxy group, and an amino group.

[0043] The "atomic group having a functional group" can be bonded by 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, and N-methylpyrrolidone.

[0044] The modified block copolymer is not particularly limited, but can be obtained, for example, by anionic living polymerization using a polymerization initiator having a functional group or an unsaturated monomer having a functional group, by forming a functional group at the living terminal, or by addition reaction of a modifying agent containing a functional group. Another method is to react a block copolymer with an organic alkali metal compound such as an organic lithium compound (metallation reaction), and then add a modifier having a functional group to the block polymer to which the organic alkali metal compound has been added. However, in the latter method, a modified hydrogenated block copolymer can also be prepared by obtaining the block copolymer (I), subjecting it to a metalation reaction, and then reacting it with a modifying agent. The temperature at which the modification reaction is carried out is preferably 0 to 150° C., more preferably 20 to 120° C. The time required for the modification reaction varies depending on other conditions, but is preferably within 24 hours, more preferably 0.1 to 10 hours.

[0045] Depending on the type of modifying agent used, amino groups etc. may generally be in the form of organometallic salts at the stage of reacting with the modifying agent, in which case they can be converted to amino groups etc. by treating with a compound having active hydrogen such as water or alcohol. Note that in such modified block copolymers, some unmodified block copolymers may be present mixed in the modified block copolymer.

[0046] The modified block copolymer may be a secondary modified block copolymer obtained by reacting the modified block copolymer with a secondary modifier that is reactive with the functional groups of the modified block copolymer. The secondary modifying agent is not particularly limited, but examples thereof include a modifying agent having a functional group selected from a carboxyl group, an acid anhydride group, an isocyanate group, an epoxy group, a silanol group, and an alkoxysilane group, and the secondary modifying agent has at least two functional groups selected from these functional groups. However, when the functional group is an acid anhydride group, it may have one acid anhydride group. As described above, when the secondary modifier is reacted with the modified block copolymer, the amount of the secondary modifier used is preferably 0.3 to 10 mol, more preferably 0.4 to 5 mol, and even more preferably 0.5 to 4 mol per equivalent of the functional group bonded to the modified block copolymer. The method for reacting the modified block copolymer with the secondary modifier is not particularly limited and may be any known method. Examples include the melt-kneading method described below and a method in which the components are dissolved or dispersed in a solvent or the like and then reacted. It is preferable that the secondary modification is carried out after the hydrogenation step. Suitable secondary modifying agents include, but are not limited to, maleic anhydride, pyromellitic anhydride, 1,2,4,5-benzenetetracarboxylic dianhydride, toluylene diisocyanate, tetraglycidyl-1,3-bisaminomethylcyclohexane, and bis-(3-triethoxysilylpropyl)-tetrasulfane. Furthermore, the block copolymer (I) of this embodiment can be a modified block copolymer graft-modified with an α,β-unsaturated carboxylic acid or a derivative thereof, such as an anhydride, ester, amidation product, or imidation product thereof. Examples of α,β-unsaturated carboxylic acids or derivatives thereof include, but are not limited to, maleic anhydride, maleic anhydride imide, acrylic acid or its ester, methacrylic acid or its ester, endo-cis-bicyclo[2,2,1]-5-heptene-2,3-dicarboxylic acid or its anhydride, and the like. The amount of the α,β-unsaturated carboxylic acid or a derivative thereof added is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the hydrogenated block copolymer (a). The reaction temperature in the case of graft modification is preferably 100 to 300°C, more preferably 120 to 280°C. The method for graft modification is not particularly limited, but for example, the method described in JP-A-62-79211 can be applied.

[0047] (Hydrogenation reaction process) The block copolymer (I) of this embodiment can be obtained by subjecting the above-described non-hydrogenated unmodified or modified block copolymer to a hydrogenation reaction using a predetermined hydrogenation catalyst. The hydrogenation catalyst is not particularly limited, and examples thereof include known catalysts such as (1) supported heterogeneous hydrogenation catalysts in which a metal such as Ni, Pt, Pd, or Ru is supported on carbon, silica, alumina, or diatomaceous earth; (2) so-called Ziegler-type hydrogenation catalysts which use a transition metal salt such as an organic acid salt or an acetylacetone salt of Ni, Co, Fe, or Cr, etc., 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. In addition, the hydrogenation catalyst is not limited to the following, but for example, the hydrogenation catalysts described in JP-B-42-8704, JP-B-43-6636, JP-B-63-4841, JP-B-1-37970, JP-B-1-53851, and JP-B-2-9041 can also be used.

[0048] Suitable hydrogenation catalysts include titanocene compounds, reducing organometallic compounds, or mixtures thereof. Examples of titanocene compounds that can be used include, but are not limited to, compounds described in JP-A-8-109219. Specific examples 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. Examples of reducing organometallic compounds include, but are not limited to, organic alkali metal compounds such as organolithium compounds, organomagnesium compounds, organoaluminum compounds, organoboron compounds, and organozinc compounds.

[0049] The hydrogenation reaction will now be described. The reaction temperature is generally preferably in the range of 0 to 200°C, more preferably in the range of 30 to 150°C. The pressure of hydrogen used in the hydrogenation reaction is preferably 0.1 to 15 MPa, more preferably 0.2 to 10 MPa, and even more preferably 0.3 to 5 MPa. The hydrogenation reaction time is usually preferably 3 minutes to 10 hours, more preferably 10 minutes to 5 hours. The hydrogenation reaction may be a batch process, a continuous process, or a combination thereof.

[0050] It is preferable to remove catalyst residues as needed from the solution of the hydrogenated block copolymer obtained through the hydrogenation reaction, and then separate the hydrogenated block copolymer from the solution. The separation method is not limited to the following, but examples include a method in which a polar solvent that is a poor solvent for the hydrogenated modified copolymer, such as acetone or alcohol, is added to the reaction solution after hydrogenation to precipitate and recover the polymer; 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 polymer; and a method in which the polymer solution is directly heated to distill off the solvent. The hydrogenated block copolymer (I) of this embodiment may contain various stabilizers such as phenol-based stabilizers, phosphorus-based stabilizers, sulfur-based stabilizers, and amine-based stabilizers.

[0051] [Resin composition] The resin composition of this embodiment contains the block copolymer (I) of this embodiment and a thermosetting resin (II). The resin composition of the present embodiment preferably further contains a phenolic curing agent (III) and a curing accelerator (IV).

[0052] (Block copolymer (I)) The resin composition of this embodiment contains the block copolymer (I) of this embodiment described above. In the resin composition of the present embodiment, the content of the block copolymer (I) is 1% by mass or more and 30% by mass or less, preferably 1% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and even more preferably 1% by mass or more and 10% by mass or less. By setting the content of the block copolymer (I) within the above range, the viscosity of the resin composition of the present embodiment tends to be reduced.

[0053] (Thermosetting resin (II)) The resin composition of the present embodiment contains a thermosetting resin (II). Examples of the thermosetting resin (II) include, but are not limited to, epoxy resins, phenolic resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, urethane resins, polyimide resins such as bismaleimide resins, polyamide resins, polyamideimide resins, silicone resins, and acrylic resins. From the viewpoints of moldability and electrical properties, the thermosetting resin (II) is preferably at least one selected from the group consisting of epoxy resins and polyimide resins, more preferably at least one selected from the group consisting of epoxy resins and bismaleimide resins, and even more preferably an epoxy resin. The resin composition of the present embodiment may contain only one type of thermosetting resin (II), or may contain two or more types.

[0054] Hereinafter, an epoxy resin will be described as an example of the thermosetting resin (II). The type of epoxy resin is not particularly limited as long as it has an epoxy group in the molecule. Examples of epoxy resins include, but are not limited to, novolac epoxy resins (phenol novolac epoxy resins, orthocresol novolac epoxy resins, etc.) obtained by epoxidizing novolac resins obtained by condensing or co-condensing, under an acid catalyst, at least one phenolic compound selected from the group consisting of phenolic compounds such as phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, etc., and naphthol compounds such as α-naphthol, β-naphthol, dihydroxynaphthalene, etc., with an aliphatic aldehyde compound such as formaldehyde, acetaldehyde, propionaldehyde, etc.; triphenylmethane epoxy resins obtained by epoxidizing triphenylmethane phenolic resins obtained by condensing or co-condensing, under an acid catalyst, the above-mentioned phenolic compounds with aromatic aldehyde compounds such as benzaldehyde, salicylaldehyde, etc.; and triphenylmethane epoxy resins obtained by co-condensing, under an acid catalyst, the above-mentioned phenolic compounds and naphthol compounds with an aldehyde compound. Copolymer epoxy resins obtained by epoxidizing novolac resins; diphenylmethane-type epoxy resins, which are diglycidyl ethers of bisphenol A, bisphenol F, etc.; biphenyl-type epoxy resins, which are diglycidyl ethers of alkyl-substituted or unsubstituted biphenols; stilbene-type epoxy resins, which are diglycidyl ethers of stilbene-based phenolic compounds; sulfur-containing epoxy resins, which are diglycidyl ethers of bisphenol S, etc.; epoxy resins, which are glycidyl ethers of alcohols such as butanediol, polyethylene glycol, and polypropylene glycol; glycidyl ester-type epoxy resins, which are glycidyl esters of polycarboxylic acids such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid; glycidylamine-type epoxy resins, in which the active hydrogen bonded to the nitrogen atom of aniline, diaminodiphenylmethane, isocyanuric acid, etc. is substituted with a glycidyl group; and dicyclopentadiene-type epoxy resins, which are epoxidized co-condensation resins of dicyclopentadiene and phenolic compounds.Alicyclic epoxy resins such as vinylcyclohexene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane, which are produced by epoxidizing the olefin bonds in the molecule; paraxylylene-modified epoxy resins, which are glycidyl ethers of paraxylylene-modified phenolic resins; metaxylylene-modified epoxy resins, which are glycidyl ethers of metaxylylene-modified phenolic resins; terpene-modified epoxy resins, which are glycidyl ethers of terpene-modified phenolic resins; and dicyclopentadiene-modified phenolic resins, which are glycidyl ethers of dicyclopentadiene-modified phenolic resins. Examples of such epoxy resins include pentadiene-modified epoxy resins, which are glycidyl ethers of cyclopentadiene-modified phenolic resins, polycyclic aromatic ring-modified epoxy resins, which are glycidyl ethers of polycyclic aromatic ring-modified phenolic resins, naphthalene-type epoxy resins, which are glycidyl ethers of naphthalene ring-containing phenolic resins, halogenated phenol novolac-type epoxy resins, hydroquinone-type epoxy resins, trimethylolpropane-type epoxy resins, linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid, and aralkyl-type epoxy resins obtained by epoxidizing aralkyl-type phenolic resins such as phenol aralkyl resins and naphthol aralkyl resins. Further examples of the epoxy resin include epoxidized acrylic resins.

[0055] From the viewpoints of compatibility with the block copolymer (I) of this embodiment and the heat resistance of a semiconductor encapsulant using the resin composition of this embodiment, the thermosetting resin (II) is preferably a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a naphthalene type epoxy resin, a cresol novolac type epoxy resin, or a dicyclopentadiene type epoxy resin, and more preferably a naphthalene type epoxy resin, a cresol novolac type epoxy resin, or a dicyclopentadiene type epoxy resin. From the viewpoint of moisture resistance, it is preferable to use a biphenyl type epoxy resin. These epoxy resins may be used alone or in combination of two or more. The softening point of the epoxy resin used in the resin composition of this embodiment is preferably 50°C or higher and 120°C or lower, more preferably 60°C or higher and 120°C or lower, and even more preferably 70°C or higher and 120°C or lower. By using an epoxy resin having a softening point within the above numerical range, the handleability, moldability, and reflow resistance during production of the resin composition of this embodiment tend to be improved. The softening point of the epoxy resin can be controlled within the above range by appropriately selecting the type of monomer that constitutes the prepolymer.

[0056] The content of the thermosetting resin (II) in the resin composition of this embodiment is 70% by mass or more from the viewpoint of heat resistance and dimensional stability of the resin composition of this embodiment, and 99% by mass or less from the viewpoint of impact resistance, flexibility, and softness, preferably 75% by mass or more and 99% by mass or less, more preferably 80% by mass or more and 99% by mass or less, even more preferably 85% by mass or more and 99% by mass or less, and still more preferably 90% by mass or more and 99% by mass or less.

[0057] (Phenol-based hardener (III)) The resin composition of the present embodiment may contain a phenol-based curing agent (III). The phenol-based curing agent (III) is not particularly limited as long as it reacts with the epoxy resin to cure it, and examples thereof include various polyhydric phenol compounds such as phenol novolac resin, cresol novolac resin, and polyvinylphenol.

[0058] (Other hardeners) The resin composition of the present embodiment may contain other curing agents in addition to the phenol-based curing agent. Other curing agents include, for example, acid anhydrides such as maleic anhydride, phthalic anhydride, and pyromellitic anhydride, and aromatic diamines such as metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

[0059] The content of the curing agent, including the phenolic curing agent and other curing agents, in the resin composition of this embodiment is preferably 5% by mass or more from the viewpoint of the heat resistance and dimensional stability of the resin composition of this embodiment, and 60% by mass or less from the viewpoint of impact resistance, flexibility, and softness, more preferably 10% by mass or more and 55% by mass or less, even more preferably 10% by mass or more and 50% by mass or less, still more preferably 10% by mass or more and 45% by mass or less, and still more preferably 10% by mass or more and 40% by mass or less.

[0060] (Curing accelerator (IV)) The resin composition of the present embodiment preferably contains a curing accelerator (IV) to promote the reaction between the thermosetting resin (II), the phenolic curing agent (III), and other curing agents. The curing accelerator (IV) is not particularly limited as long as it accelerates the curing reaction, and examples thereof include imidazole compounds such as 2-methylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 2-heptadecylimidazole; tertiary amine compounds such as triethylamine, benzyldimethylamine, α-methylbenzyldimethylamine, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)undecene-7; organometallic compounds such as zirconium tetramethoxide, zirconium tetrapropoxide, tetrakis(acetylacetonato)zirconium, and tri(acetylacetonato)aluminum; and organic phosphine compounds such as triphenylphosphine, trimethylphosphine, triethylphosphine, tributylphosphine, tri(p-methylphenyl)phosphine, and tri(nonylphenyl)phosphine.

[0061] When the resin composition of the present embodiment contains the block copolymer (I), the thermosetting resin (II), the phenolic curing agent (III), and the curing accelerator (IV), the content of the block copolymer (I) is preferably 1 to 10 mass%. The content of the thermosetting resin (II) is preferably 70 to 80 mass %. The content of the phenolic curing agent (III) is preferably 10 to 30 mass %. The content of the curing accelerator (IV) is preferably 0.1% by mass or more from the viewpoint of reactivity, and is preferably 5% by mass or less from the viewpoint of suppressing a rapid reaction with the modifying group of the block copolymer (I), more preferably 0.3 to 4.5% by mass, even more preferably 0.5 to 4% by mass, and even more preferably 1 to 2% by mass.

[0062] (filler) The resin composition of the present embodiment may contain a filler. Examples of fillers include, but are not limited to, amorphous silica, crystalline silica, calcium carbonate, magnesium carbonate, alumina, magnesia, clay, talc, calcium silicate, titanium oxide, antimony oxide, asbestos, and glass fiber. In particular, amorphous silica is preferably used because it has a large effect of reducing the linear expansion coefficient and is effective in reducing stress. Examples of amorphous silica include fused silica produced by melting quartz and synthetic silica produced by various synthesis methods, and crushed or spherical silica is used. In particular, spherical silica is desirable from the viewpoint of improving fluidity, and its shape is preferably close to a perfect sphere to improve fluidity. The amount of fine powder with a particle size of 3 μm or less in the filler is preferably 3 to 45 mass %, more preferably 10 to 35 mass %.

[0063] (Flame retardants and other additives) The resin composition of the present embodiment may further contain various additives, such as halogen compounds such as halogenated epoxy, flame retardants such as phosphorus, flame retardant assistants such as antimony compounds, carbon black and various colorants, long-chain fatty acids and derivatives thereof, various mold release agents such as paraffin wax and polyethylene wax, ion scavengers such as hydrotalcites, and organic peroxides.

[0064] [Molded body] The molded article of this embodiment is an article molded from the resin composition of this embodiment described above. The molded article can be produced by a conventionally known method, and the molding method is not particularly limited, but it can be produced by, for example, compression molding. The shape of the molded body is not particularly limited, but is preferably tablet-shaped from the viewpoint of easy semiconductor encapsulation. When the molded body is tablet-shaped, it is preferable from the viewpoint of handleability that the dimensions and mass of the molded body be set to be suitable for the molding conditions of the package.

[0065] [Semiconductor encapsulation material] The molded article of this embodiment can be used as a semiconductor encapsulation material. The resin composition of the present embodiment, including its cured product, can be used in a variety of applications. For example, the epoxy resin composition can be used in semiconductor encapsulation resin compositions for semiconductor packages. Examples of encapsulation molding methods for semiconductor packages include transfer molding and underfill methods. The encapsulation epoxy resin composition is preferably in the form of a liquid, powder, granules, tablet, or sheet. In the case of transfer molding, the encapsulant is added in tablet form, so it must essentially be solid. From the viewpoints of heat resistance, moisture resistance, and flame retardancy, dicyclopentadiene epoxy, brominated epoxy, cresol novolac epoxy, biphenyl epoxy, and naphthol novolac epoxy are preferred. From the same viewpoints, phenol novolac, aralkyl novolac, dicyclopentadiene phenol, and trisphenol methane are preferred as curing agents. In the case of die-and-fill and underfill methods, the encapsulation resin must essentially be in liquid form. From the viewpoints of heat resistance and moisture resistance, bisphenol A-type epoxy and naphthalene epoxy are preferred, with naphthalene epoxy being more preferred.

[0066] [Method for producing resin composition] The resin composition of the present embodiment can be produced by a conventionally known method. The resin composition of the present embodiment can be produced by, but is not limited to, a method of melt-kneading the components (block copolymer (I), thermosetting resin (II), curing agent (III), curing accelerator (IV), and optionally fillers and other additives) using a mixer such as a high-shear mixer, a Banbury mixer, a roll, a single-screw extruder, a twin-screw extruder, a co-kneader, or a multi-screw extruder, or a method of dissolving or dispersing the components and then removing the solvent by heating. In particular, a melt-kneading method using a high-shear mixer and rolls is preferable from the viewpoint of productivity and good kneading properties.

[0067] The method for producing a resin composition according to the present embodiment is characterized in that the block copolymer (I) and the epoxy resin as the thermosetting resin (II) can be produced without using a solvent. The block copolymer (I) of the present embodiment exhibits sufficient melting properties within a temperature range in which the solid epoxy does not undergo a self-reaction and is melt-processable, and therefore, an epoxy resin composition can be easily produced within the following temperature range. The kneading temperature during production of the resin composition of this embodiment is preferably 70°C or higher from the viewpoint of the softening temperature of the epoxy resin as the thermosetting resin (II) and 180°C or lower from the viewpoint of suppressing self-reaction of the epoxy resin during kneading, more preferably 80°C or higher and 170°C or lower, even more preferably 90°C or higher and 160°C or lower, and even more preferably 100°C or higher and 150°C or lower. The stirring speed when kneading the resin composition of this embodiment is not particularly limited, but from the viewpoint of compatibility between the epoxy resin as the thermosetting resin (II) and the block copolymer (I), it is 250 rpm or more, preferably 500 rpm or more, more preferably 1000 rpm or more, even more preferably 1500 rpm or more, and still more preferably 2000 rpm or more. There is no upper limit. The shape of the resin composition of the present embodiment is not limited to the following, and may be any shape, such as tablet, pellet, sheet, strand, chip, etc. Furthermore, after melt-kneading, a molded article may be produced directly. When the resin composition of the present embodiment is used as a semiconductor encapsulant, which will be described later, it is preferably in the form of a tablet from the viewpoint of the encapsulation process. [Example]

[0068] The present invention will be described in detail below with reference to specific examples and comparative examples, but the present invention is not limited to the following examples and comparative examples. The methods for measuring and evaluating physical properties used in the examples and comparative examples are shown below.

[0069] [Method for identifying the structure of a block copolymer] ((1) Content of all aromatic vinyl monomer units (styrene) in block copolymer (I)) Using the block copolymer before hydrogenation, the content (mass %) of all aromatic vinyl monomer units (styrene) was measured with an ultraviolet spectrophotometer (Shimadzu Corporation, UV-2450).

[0070] ((2-1) Content of Polymer Block (Polystyrene Block) (A) Mainly Containing Aromatic Vinyl Monomer Units in Block Copolymer (I)) The block copolymer before hydrogenation was used to measure the content (mass%) of the polymer block (A) mainly composed of aromatic vinyl monomer units 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").

[0071] ((2-2) Content of polymer block (B) mainly composed of conjugated diene monomer units in block copolymer (I)) Using the block copolymer before hydrogenation, the content (mass %) of the polymer block (B) mainly composed of conjugated diene monomer units in the block copolymer (I) was measured by the same NMR method as described above.

[0072] ((2-3) Content of polymer block (C) consisting of aromatic vinyl monomer units and conjugated diene monomer units in block copolymer (I)) Using the block copolymer before hydrogenation, the content (mass%) of the polymer block (C) consisting of aromatic vinyl monomer units and conjugated diene monomer units in the block copolymer (I) was measured by the same NMR method as described above.

[0073] ((3) Amount of 1,2-vinyl bonds in block copolymer (I)) The amount of 1,2-vinyl bonds in the block copolymer before hydrogenation was measured using an infrared spectrophotometer (FT / IR-4100, manufactured by JASCO Corporation). The amount of 1,2-vinyl bonds in the block copolymer was calculated by the Hampton method.

[0074] ((4) Weight-average molecular weight Mw of block copolymer (I) The weight average molecular weight of the block copolymer (I) was measured by GPC [apparatus: HLC-82209PC (manufactured by Tosoh Corporation), column: TSKgeguard column SuperHZ-L (4.6 mm×20 cm)×3]. The solvent used was tetrahydrofuran. The measurements were carried out at a temperature of 35°C. The weight average molecular weight was determined by using the molecular weight of the peak in the chromatogram and a calibration curve (prepared using the peak molecular weight of the standard polystyrene) obtained by measuring commercially available standard polystyrene. When there are multiple peaks in the chromatogram, 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) was used as the weight average molecular weight (Mw). The molecular weight distribution (Mw / Mn) was also calculated from the ratio of Mw / Mn by measuring the number average molecular weight (Mn) by GPC in the same manner.

[0075] ((5) Hydrogenation Ratio of Double Bonds of Conjugated Diene Monomer Units of Block Copolymer (I)) The hydrogenation rate of the double bonds of the conjugated diene monomer units was measured using a block copolymer with a nuclear magnetic resonance spectrometer (ECS400, manufactured by JEOL RESONANCE).

[0076] ((6) Content of aromatic vinyl monomer units contained in polymer block (C)) The block copolymer before hydrogenation was used as a sample and measured 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") to measure the total aromatic vinyl monomer unit content in the block copolymer (I) and the content of the polymer block mainly composed of vinyl aromatic monomer units in the block copolymer (I). From this, the content of aromatic vinyl monomer units contained in the copolymer block (C) relative to the entire block copolymer (I) was calculated.

[0077] [Methods for measuring the physical properties and characteristics of block copolymers] ((1) tanδ peak temperature and storage modulus G') First, a "press-molded sheet" manufactured as described below was cut into a size of 12.5 mm in width and 40 mm in length to prepare a measurement sample. Next, this measurement sample was set in the torsion type geometry of the ARES (manufactured by TA Instruments Corporation, trade name) device, and the tan δ peak temperature was determined under the conditions of an effective measurement length of 25 mm, a strain of 0.5%, a frequency of 1 Hz, and a heating rate of 3°C / min. The tan δ peak temperature and storage modulus G' were values determined from peaks detected by automatic measurement using RSI Orchestrator (manufactured by TA Instruments Co., Ltd., trade name).

[0078] (2) Melt flow rate (hereinafter referred to as MFR, unit: g / 10 min) The MFR was measured in accordance with JIS K7210 under conditions of a temperature of 230°C and a load of 2.16 kg.

[0079] (3) Tensile strength Measured according to JIS K6251 using a No. 3 dumbbell at a crosshead speed of 500 mm / min. The value of the maximum strength in the stress-strain curve was taken as the tensile strength and was evaluated according to the following criteria. <Evaluation criteria> ◎: 35MPa or more 〇: 30MPa or more and less than 35MPa ×: Less than 30 MPa

[0080] ((4) Flexibility) According to JIS K6251, using a No. 3 dumbbell and a crosshead speed of 500 mm / min. Measured. The value of the displacement at break (breaking elongation) was used as an index of flexibility, and was evaluated according to the following evaluation criteria. <Evaluation criteria> ◎: 400% or more ○: 300% or more but less than 400% ×: Less than 300%

[0081] ((5) Hardness) The instantaneous hardness of the block copolymer (I) was measured using a durometer type D in accordance with JIS K6253. The hardness value was measured the instant the probe of the hardness tester was lowered onto the measurement sample. The measurement sample was a sheet laminate in which three 2 mm thick sheets prepared by pressing the block copolymer (I) at 180° C. for 3 minutes were stacked. <Evaluation criteria> ◎:D hardness 40 or less 〇: D hardness is over 40 and 45 or less ×: D hardness exceeds 45

[0082] [Production of Block Copolymer] (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. An n-hexane solution containing 200 mmol of trimethylaluminum was added to the mixture while thoroughly stirring, and the mixture was allowed to react at room temperature for about 3 days, thereby obtaining a hydrogenation catalyst.

[0083] (Preparation of block copolymers) Block copolymers 1 to 23 constituting the resin composition were prepared by the following procedure.

[0084] Example 1: Block Copolymer 1 Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 5 parts by mass of styrene (concentration: 20% by mass) was added. Next, 36.7 mL of n-butyllithium (2.4 mol / L), 4.4 mL of N,N,N',N'-tetramethylethylenediamine (6.7 mol / L) (hereinafter referred to as "TMEDA"), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65°C for 5 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 90 parts by mass of butadiene was added, and polymerization was carried out at 65°C for 60 minutes. Next, a cyclohexane solution (concentration 20% by mass) containing 5 parts by mass of styrene was added, and polymerization was carried out at 65°C for 5 minutes. After that, 6.9 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and the reaction was carried out. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 10% by mass, a polystyrene block content of 10% by mass, a total vinyl bond content in the block copolymer of 45% by mass, and a weight average molecular weight of 42,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer to obtain a hydrogenated block copolymer 1. The hydrogenation rate of the obtained hydrogenated block copolymer 1 was 80%. Other physical properties are shown in the table below.

[0085] Example 2: Block Copolymer 2 Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 7.5 parts by mass of styrene (concentration: 20% by mass) was added. Next, 35.3 mL of n-butyllithium (2.4 mol / L), 4.1 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 10 minutes. Next, a cyclohexane solution (20% by mass) containing 70 parts by mass of butadiene was added, and polymerization was carried out at 65°C for 50 minutes. Next, a cyclohexane solution (20% by mass) containing 15 parts by mass of styrene was added, and polymerization was carried out at 65°C for 10 minutes. After that, 6.5 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and the reaction was carried out. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 30% by mass, a polystyrene block content of 30% by mass, a total vinyl bond content in the block copolymer of 43% by mass, and a weight average molecular weight of 45,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer to obtain a hydrogenated block copolymer 2. The hydrogenation rate of the obtained hydrogenated block copolymer 2 was 83%. Other physical properties are shown in the table below.

[0086] Example 3: Block Copolymer 3 Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 25 parts by mass of styrene (concentration: 20% by mass) was added. Next, 36.7 mL of n-butyllithium (2.4 mol / L), 4.4 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 20 minutes. Next, a cyclohexane solution (20% by mass) containing 50 parts by mass of butadiene was added, and polymerization was carried out at 65°C for 40 minutes. Next, a cyclohexane solution (20% by mass) containing 25 parts by mass of styrene was added, and polymerization was carried out at 65°C for 20 minutes. After that, 6.8 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and the reaction was carried out. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 50% by mass, a polystyrene block content of 50% by mass, a total vinyl bond content in the block copolymer of 46% by mass, and a weight average molecular weight of 47,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer, and hydrogenated block copolymer 3 was obtained. The hydrogenation rate of the obtained hydrogenated block copolymer 3 was 80%. Other physical properties are shown in the table below.

[0087] Example 4: Block Copolymer 4 Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 15 parts by mass of styrene (concentration: 20% by mass) was added. Next, 34.2 mL of n-butyllithium (2.4 mol / L), 10.5 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 10 minutes. Next, a cyclohexane solution (20% by mass) containing 70 parts by mass of butadiene was added, and polymerization was carried out at 65°C for 40 minutes. Next, a cyclohexane solution (20% by mass) containing 15 parts by mass of styrene was added, and polymerization was carried out at 65°C for 5 minutes. After that, 6.2 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and the reaction was carried out. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 30% by mass, a polystyrene block content of 30% by mass, a total vinyl bond content in the block copolymer of 73% by mass, and a weight average molecular weight of 48,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer, and hydrogenated block copolymer 4 was obtained. The hydrogenation rate of the obtained hydrogenated block copolymer 4 was 81%. Other physical properties are shown in the table below.

[0088] Example 5: Block Copolymer 5 Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 5 parts by mass of styrene (concentration: 20% by mass) was added. Next, 36.2 mL of n-butyllithium (2.4 mol / L), 4.6 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 5 minutes. Next, a cyclohexane solution (20% by mass) containing 53 parts by mass of styrene and a cyclohexane solution (20% by mass) containing 37 parts by mass of butadiene were added and polymerized at 65°C for 70 minutes. Next, a cyclohexane solution (20% by mass) containing 5 parts by mass of styrene was added and polymerized at 65°C for 5 minutes. After that, 6.7 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and allowed to react. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 63% by mass, a polystyrene block content of 10% by mass, a total vinyl bond content in the block copolymer of 44% by mass, and a weight average molecular weight of 45,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer, and hydrogenated block copolymer 5 was obtained. The hydrogenation rate of the obtained hydrogenated block copolymer 5 was 80%. Other physical properties are shown in the table below.

[0089] Example 6: Block Copolymer 6 Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 15 parts by mass of styrene (concentration: 20% by mass) was added. Next, 37.8 mL of n-butyllithium (2.4 mol / L), 4.8 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 15 minutes. Next, a cyclohexane solution (20% by mass) containing 41 parts by mass of styrene and a cyclohexane solution (20% by mass) containing 39 parts by mass of butadiene were added and polymerized at 65°C for 60 minutes. Next, a cyclohexane solution (20% by mass) containing 15 parts by mass of styrene was added and polymerized at 65°C for 15 minutes. After that, 7.0 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and the reaction was continued. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 71% by mass, a polystyrene block content of 30% by mass, a total vinyl bond content in the block copolymer of 46% by mass, and a weight average molecular weight of 43,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer, and hydrogenated block copolymer 6 was obtained. The hydrogenation rate of the obtained hydrogenated block copolymer 6 was 85%. Other physical properties are shown in the table below.

[0090] Example 7: Block Copolymer 7 Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 25 parts by mass of styrene (concentration: 20% by mass) was added. Next, 36.0 mL of n-butyllithium (2.4 mol / L), 4.5 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 18 minutes. Next, a cyclohexane solution (20% by mass) containing 29 parts by mass of styrene and a cyclohexane solution (20% by mass) containing 21 parts by mass of butadiene were added and polymerized at 65°C for 50 minutes. Next, a cyclohexane solution (20% by mass) containing 25 parts by mass of styrene was added and polymerized at 65°C for 18 minutes. After that, 6.6 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and allowed to react. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 79% by mass, a polystyrene block content of 50% by mass, a total vinyl bond content in the block copolymer of 43% by mass, and a weight average molecular weight of 46,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer to obtain hydrogenated block copolymer 7. The hydrogenation rate of the obtained hydrogenated block copolymer 7 was 83%. Other physical properties are shown in the table below.

[0091] Example 8: Block Copolymer 8 Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 5 parts by mass of styrene (concentration: 20% by mass) was added. Next, 34.5 mL of n-butyllithium (2.4 mol / L), 4.2 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 5 minutes. Next, a cyclohexane solution containing 50 parts by mass of styrene (concentration 20% by mass) and a cyclohexane solution containing 35 parts by mass of butadiene (concentration 20% by mass) were added and polymerized at 65° C. for 60 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 5 parts by mass of butadiene was added and polymerization was carried out at 65° C. for 10 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 5 parts by mass of styrene was added and polymerization was carried out at 65° C. for 5 minutes. Then, 6.2 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and the reaction was continued. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 60% by mass, a polystyrene block content of 10% by mass, a total vinyl bond content in the block copolymer of 47% by mass, and a weight average molecular weight of 48,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer, and hydrogenated block copolymer 8 was obtained. The hydrogenation rate of the obtained hydrogenated block copolymer 8 was 83%. Other physical properties are shown in the table below.

[0092] Example 9: Block Copolymer 9 Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 15 parts by mass of styrene (concentration: 20% by mass) was added. Next, 34.1 mL of n-butyllithium (2.4 mol / L), 4.2 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 18 minutes. Next, a cyclohexane solution containing 38 parts by mass of styrene (concentration 20% by mass) and a cyclohexane solution containing 27 parts by mass of butadiene (concentration 20% by mass) were added and polymerized at 65° C. for 50 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 5 parts by mass of butadiene was added and polymerization was carried out at 65° C. for 10 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 15 parts by mass of styrene was added and polymerization was carried out at 65° C. for 18 minutes. Then, 6.1 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and the reaction was continued. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 68% by mass, a polystyrene block content of 30% by mass, a total vinyl bond content in the block copolymer of 45% by mass, and a weight average molecular weight of 49,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer, and hydrogenated block copolymer 9 was obtained. The hydrogenation rate of the obtained hydrogenated block copolymer 9 was 81%. Other physical properties are shown in the table below.

[0093] Example 10: Block Copolymer 10 Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 25 parts by mass of styrene (concentration: 20% by mass) was added. Next, 35.2 mL of n-butyllithium (2.4 mol / L), 4.2 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 20 minutes. Next, a cyclohexane solution containing 26 parts by mass of styrene (concentration 20% by mass) and a cyclohexane solution containing 19 parts by mass of butadiene (concentration 20% by mass) were added and polymerized at 65° C. for 45 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 5 parts by mass of butadiene was added and polymerization was carried out at 65° C. for 10 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 25 parts by mass of styrene was added and polymerization was carried out at 65° C. for 20 minutes. Then, 6.4 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and the reaction was continued. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 76% by mass, a polystyrene block content of 50% by mass, a total vinyl bond content in the block copolymer of 44% by mass, and a weight average molecular weight of 47,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer to obtain a hydrogenated block copolymer 10. The hydrogenation rate of the resulting hydrogenated block copolymer 10 was 83%. Other physical properties are shown in the table below.

[0094] Example 11: Block Copolymer 11 Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 5 parts by mass of styrene (concentration: 20% by mass) was added. Next, 34.3 mL of n-butyllithium (2.4 mol / L), 4.7 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 5 minutes. Next, a cyclohexane solution containing 44 parts by mass of styrene (concentration 20% by mass) and a cyclohexane solution containing 31 parts by mass of butadiene (concentration 20% by mass) were added and polymerized at 65° C. for 60 minutes. Next, a cyclohexane solution containing 9 parts by mass of butadiene (concentration: 20% by mass) was added and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 5 parts by mass of styrene was added and polymerization was carried out at 65° C. for 5 minutes. Next, a cyclohexane solution containing 6 parts by mass of butadiene (concentration: 20% by mass) was added and polymerization was carried out at 65° C. for 10 minutes. Then, 6.2 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and the reaction was continued. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 54% by mass, a polystyrene block content of 10% by mass, a total vinyl bond content in the block copolymer of 44% by mass, and a weight average molecular weight of 48,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer to obtain a hydrogenated block copolymer 11. The hydrogenation rate of the resulting hydrogenated block copolymer 11 was 85%. Other physical properties are shown in the table below.

[0095] Example 12: Block Copolymer 12 Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 15 parts by mass of styrene (concentration: 20% by mass) was added. Next, 33.0 mL of n-butyllithium (2.4 mol / L), 4.2 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution containing 32 parts by mass of styrene (concentration 20% by mass) and a cyclohexane solution containing 23 parts by mass of butadiene (concentration 20% by mass) were added and polymerized at 65° C. for 50 minutes. Next, a cyclohexane solution containing 9 parts by mass of butadiene (concentration: 20% by mass) was added and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 15 parts by mass of styrene was added and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution containing 6 parts by mass of butadiene (concentration: 20% by mass) was added and polymerization was carried out at 65° C. for 10 minutes. Then, 5.9 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and the reaction was continued. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 62% by mass, a polystyrene block content of 30% by mass, a total vinyl bond content in the block copolymer of 45% by mass, and a weight average molecular weight of 51,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer to obtain a hydrogenated block copolymer 12. The hydrogenation rate of the resulting hydrogenated block copolymer 12 was 82%. Other physical properties are shown in the table below.

[0096] Example 13: Block Copolymer 13 Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 25 parts by mass of styrene (concentration: 20% by mass) was added. Next, 32.7 mL of n-butyllithium (2.4 mol / L), 4.2 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 20 minutes. Next, a cyclohexane solution containing 21 parts by mass of styrene (concentration 20% by mass) and a cyclohexane solution containing 14 parts by mass of butadiene (concentration 20% by mass) were added and polymerized at 65° C. for 50 minutes. Next, a cyclohexane solution containing 9 parts by mass of butadiene (concentration: 20% by mass) was added and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 25 parts by mass of styrene was added and polymerization was carried out at 65° C. for 20 minutes. Next, a cyclohexane solution containing 6 parts by mass of butadiene (concentration: 20% by mass) was added and polymerization was carried out at 65° C. for 10 minutes. Then, 5.8 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and the reaction was continued. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 71% by mass, a polystyrene block content of 50% by mass, a total vinyl bond content in the block copolymer of 46% by mass, and a weight average molecular weight of 52,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer, and a hydrogenated block copolymer 13 was obtained. The hydrogenation rate of the resulting hydrogenated block copolymer 13 was 88%. Other physical properties are shown in the table below.

[0097] Example 14: Block Copolymer 14 Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 15 parts by mass of styrene (concentration: 20% by mass) was added. Next, 32.5 mL of n-butyllithium (2.4 mol / L), 4.0 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution containing 32 parts by mass of styrene (concentration 20% by mass) and a cyclohexane solution containing 23 parts by mass of butadiene (concentration 20% by mass) were added and polymerized at 65° C. for 50 minutes. Next, a cyclohexane solution containing 9 parts by mass of butadiene (concentration: 20% by mass) was added and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 15 parts by mass of styrene was added and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 6 parts by mass of butadiene was added, and polymerization was carried out for 10 minutes at 65° C. Thereafter, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 62% by mass, a polystyrene block content of 30% by mass, a total vinyl bond content in the block copolymer of 46% by mass, and a weight average molecular weight of 52,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer. The hydrogenation rate of the resulting block copolymer 14 was 81%. 100 parts by mass of this block copolymer and 1.7 parts by mass of maleic anhydride were fed through the throat of a twin-screw extruder whose entire length was set to 150 to 200°C, and 0.12 parts by mass of an organic peroxide (Peroxide 25B (NOF Corporation)) was fed through a feed port downstream of the twin-screw extruder to compound them. The strands discharged from the extruder outlet were pelletized. The pellets obtained as described above were dried in a dry oven at about 80° C. for 3 hours to obtain hydrogenated block copolymer 14. Other physical properties are shown in the table below.

[0098] Example 15: Block Copolymer 15 Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 15 parts by mass of styrene (concentration: 20% by mass) was added. Next, 32.5 mL of n-butyllithium (2.4 mol / L), 4.0 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution containing 32 parts by mass of styrene (concentration 20% by mass) and a cyclohexane solution containing 23 parts by mass of butadiene (concentration 20% by mass) were added and polymerized at 65° C. for 50 minutes. Next, a cyclohexane solution containing 9 parts by mass of butadiene (concentration: 20% by mass) was added and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 15 parts by mass of styrene was added and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 6 parts by mass of butadiene was added, and polymerization was carried out for 10 minutes at 65° C. Thereafter, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 62% by mass, a polystyrene block content of 30% by mass, a total vinyl bond content in the block copolymer of 46% by mass, and a weight average molecular weight of 52,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer. The hydrogenation rate of the resulting block copolymer 15 was 98%. Other physical properties are shown in the table below.

[0099] (Comparative Example 1: Block Copolymer 16) Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. A cyclohexane solution containing 100 parts by mass of styrene (concentration: 20% by mass) was added. Next, 34.0 mL of n-butyllithium (2.4 mol / L) was added, and polymerization was carried out for 60 minutes at 70° C. Thereafter, heptanol was added to terminate the polymerization reaction. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer, thereby obtaining block copolymer 16.

[0100] (Comparative Example 2: Block Copolymer 17) Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, 7.9 L of cyclohexane was charged into a tank reactor, and 34.0 mL of n-butyllithium (2.4 mol / L), 4.3 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added. Next, a cyclohexane solution containing 59 parts by mass of styrene (concentration 20% by mass) and a cyclohexane solution containing 41 parts by mass of butadiene (concentration 20% by mass) were added and polymerized at 65° C. for 80 minutes. Then, 6.1 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and the reaction was continued. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 59% by mass, a total vinyl bond content in the block copolymer of 46% by mass, and a weight-average molecular weight of 49,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer, and a hydrogenated block copolymer 17 was obtained. The hydrogenation rate of the obtained hydrogenated block copolymer 17 was 80%. Other physical properties are shown in the table below.

[0101] (Comparative Example 3: Block Copolymer 18) Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 5 parts by mass of styrene (concentration: 20% by mass) was added. Next, 35.0 mL of n-butyllithium (2.4 mol / L), 9.5 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 5 minutes. Next, a cyclohexane solution containing 56 parts by mass of styrene (concentration 20% by mass) and a cyclohexane solution containing 39 parts by mass of butadiene (concentration 20% by mass) were added and polymerized at 65° C. for 70 minutes. Then, 6.4 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and the reaction was continued. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 61% by mass, a polystyrene block content of 5% by mass, a total vinyl bond content in the block copolymer of 73% by mass, and a weight average molecular weight of 47,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer to obtain a hydrogenated block copolymer 18. The hydrogenation rate of the resulting hydrogenated block copolymer 18 was 85%. Other physical properties are shown in the table below.

[0102] (Comparative Example 4: Block Copolymer 19) Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 30 parts by mass of styrene (concentration: 20% by mass) was added. Next, 33.5 mL of n-butyllithium (2.4 mol / L), 3.9 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 25 minutes. Next, a cyclohexane solution (20% by mass) containing 23 parts by mass of styrene and a cyclohexane solution (20% by mass) containing 17 parts by mass of butadiene were added and polymerized at 65°C for 35 minutes. Next, a cyclohexane solution (20% by mass) containing 30 parts by mass of styrene was added and polymerized at 65°C for 25 minutes. After that, 6.0 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and allowed to react. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 83% by mass, a polystyrene block content of 60% by mass, a total vinyl bond content in the block copolymer of 44% by mass, and a weight average molecular weight of 51,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer to obtain a hydrogenated block copolymer 19. The hydrogenation rate of the resulting hydrogenated block copolymer 19 was 83%. Other physical properties are shown in the table below.

[0103] (Comparative Example 5: Block Copolymer 20) Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 15 parts by mass of styrene (concentration: 20% by mass) was added. Next, 34.0 mL of n-butyllithium (2.4 mol / L), 3.9 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution containing 32 parts by mass of styrene (concentration 20% by mass) and a cyclohexane solution containing 23 parts by mass of butadiene (concentration 20% by mass) were added and polymerized at 65° C. for 50 minutes. Next, a cyclohexane solution containing 9 parts by mass of butadiene (concentration: 20% by mass) was added and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 15 parts by mass of styrene was added and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution containing 6 parts by mass of butadiene (concentration: 20% by mass) was added and polymerization was carried out at 65° C. for 10 minutes. Then, 6.1 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and the reaction was continued. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 62% by mass, a polystyrene block content of 30% by mass, a total vinyl bond content in the block copolymer of 43% by mass, and a weight average molecular weight of 49,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer to obtain a hydrogenated block copolymer 20. The hydrogenation rate of the resulting hydrogenated block copolymer 20 was 15%. Other physical properties are shown in the table below.

[0104] (Comparative Example 6: Block Copolymer 21) Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 15 parts by mass of styrene (concentration: 20% by mass) was added. Next, 24.0 mL of n-butyllithium (2.4 mol / L), 3.2 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution containing 32 parts by mass of styrene (concentration 20% by mass) and a cyclohexane solution containing 23 parts by mass of butadiene (concentration 20% by mass) were added and polymerized at 65° C. for 50 minutes. Next, a cyclohexane solution containing 9 parts by mass of butadiene (concentration: 20% by mass) was added and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 15 parts by mass of styrene was added and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution containing 6 parts by mass of butadiene (concentration: 20% by mass) was added and polymerization was carried out at 65° C. for 10 minutes. Then, 3.7 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and the reaction was continued. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 62% by mass, a polystyrene block content of 30% by mass, a total vinyl bond content in the block copolymer of 48% by mass, and a weight average molecular weight of 81,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer to obtain a hydrogenated block copolymer 21. The hydrogenation rate of the resulting hydrogenated block copolymer 21 was 86%. Other physical properties are shown in the table below.

[0105] (Comparative Example 7: Block Copolymer 22) Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 15 parts by mass of styrene (concentration: 20% by mass) was added. Next, 60.3 mL of n-butyllithium (2.4 mol / L), 7.7 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution containing 32 parts by mass of styrene (concentration 20% by mass) and a cyclohexane solution containing 23 parts by mass of butadiene (concentration 20% by mass) were added and polymerized at 65° C. for 50 minutes. Next, a cyclohexane solution containing 9 parts by mass of butadiene (concentration: 20% by mass) was added and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 15 parts by mass of styrene was added and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution containing 6 parts by mass of butadiene (concentration: 20% by mass) was added and polymerization was carried out at 65° C. for 10 minutes. Then, 6.1 mL of 1,3-dimethyl-2-imidazolidinone (9.3 mol / L) was added and the reaction was continued. Finally, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 62% by mass, a polystyrene block content of 30% by mass, a total vinyl bond content in the block copolymer of 43% by mass, and a weight average molecular weight of 24,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer to obtain a hydrogenated block copolymer 22. The hydrogenation rate of the resulting hydrogenated block copolymer 22 was 83%. Other physical properties are shown in the table below.

[0106] (Comparative Example 8: Block Copolymer 23) Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 15 parts by mass of styrene (concentration: 20% by mass) was added. Next, 25.7 mL of n-butyllithium (2.4 mol / L), 3.5 mL of TMEDA (6.7 mol / L), and 0.04 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution containing 32 parts by mass of styrene (concentration 20% by mass) and a cyclohexane solution containing 23 parts by mass of butadiene (concentration 20% by mass) were added and polymerized at 65° C. for 50 minutes. Next, a cyclohexane solution containing 9 parts by mass of butadiene (concentration: 20% by mass) was added and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 15 parts by mass of styrene was added and polymerization was carried out at 65° C. for 12 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 6 parts by mass of butadiene was added, and polymerization was carried out for 10 minutes at 65° C. Thereafter, heptanol was added to terminate the polymerization reaction. The block copolymer obtained as described above had a styrene content of 62% by mass, a polystyrene block content of 30% by mass, a total vinyl bond content in the block copolymer of 43% by mass, and a weight average molecular weight of 73,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the resulting block copolymer in an amount of 100 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 65°C. Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the block copolymer to obtain a hydrogenated block copolymer 23. The hydrogenation rate of the obtained hydrogenated block copolymer 23 was 15%. Other physical properties are shown in the table below.

[0107] [Table 1]

[0108] [Table 2]

[0109] [Table 3]

[0110] [Production of Resin Composition and Evaluation of Physical Properties] A resin composition was produced using the block copolymer (component (I)) obtained as described above and the following components. Component (I): Block copolymers 1 to 23 Component (II): Naphthalene-type epoxy resin, HP-6000 (DIC Corporation) Component (III): Novolac-type phenolic resin curing agent, TD-2131 (manufactured by DIC Corporation) Component (IV): Triphenylphosphine (hereinafter referred to as TPP), Tokyo Chemical Industry Co., Ltd.

[0111] (Production Examples 1 to 15), (Production Comparative Examples 1 to 8) First, component (I) / component (II) / component (III) were dry-blended in a mass ratio of 5 / 100 / 50, and the mixture was placed in a 700 mL metal can. Next, the metal can was placed in an oil bath set to 140°C, and the mixture was kneaded for 20 minutes at a rotation speed of 2000 rpm using a high-shear mixer (manufactured by Silverson), while the temperature inside the metal can was controlled to 130°C. Next, 3 parts by mass of triphenylphosphine was added, and the mixture was kneaded at a rotation speed of 2000 rpm for 1 minute to obtain a resin composition. The obtained resin composition was poured into a JIS No. 1 dumbbell mold made of Teflon (registered trademark) and cured for 120 minutes in a hydraulic press set at 180°C to obtain a test piece of the epoxy cured resin composition. Using this test piece, various physical properties were evaluated by the following methods. The results are shown in the table below.

[0112] ((1) Solubility in epoxy resin) The epoxy resin and the block copolymer (I) were kneaded at 130°C and 2500 rpm for 20 minutes, and immediately after that, the state of separation between the epoxy resin and the block copolymer was visually confirmed to evaluate the solubility in the epoxy resin. <Evaluation criteria> ◯: There is no unmelted block copolymer (I) in the kneading vessel. ×: Unmelted block copolymer (I) remains in the kneading vessel.

[0113] (2) Melt viscosity (unit: mPa·s) The melt viscosity of the epoxy resin composition was measured by the EMS method (method described in Patent No. 5093599 of the University of Tokyo, National University Corporation) at a temperature of 130°C and a shear rate of 1000 rpm, and evaluated according to the following criteria. For the measurements, an EMS viscometer "EMS-1000S" manufactured by Kyoto Electronics Manufacturing Co., Ltd. was used. <Evaluation criteria> ◎: Melt viscosity at 130℃ is 850 mPa·s or less ○: Melt viscosity at 130℃ is more than 850 mPa·s and less than 900 mPa·s ×: Melt viscosity at 130°C exceeds 900 mPa·s

[0114] (3) Whether or not gelation occurs during hardening heating The resin composition was compression molded at 180°C for 120 minutes to prepare a cured sheet molded product having a thickness of 300 µm. Any unmelted material present in the sheet molded product was visually confirmed. <Evaluation criteria> ◯: No unmelted material was generated and the sheet was uniform. ×: Unmelted material was generated and the sheet was not uniform.

[0115] (4) Tensile strength The resin composition was compression molded at 180° C. for 120 minutes to prepare a pressed sheet (thickness: 300 μm), and the tensile strength was measured using a No. 1 dumbbell at a crosshead speed of 1 mm / min according to JIS K6251. The value of the maximum strength in the stress-strain curve was taken as the tensile strength, and was evaluated according to the following criteria. <Evaluation criteria> ◎: Maximum strength exceeds 80 MPa when pulled at 1 mm / min ○: Maximum strength when pulled at 1 mm / min is over 50 MPa and 80 MPa or less ×: Maximum strength when pulled at 1 mm / min is 50 MPa or less

[0116] ((5) Breaking Elongation) The same test as for the tensile strength as described above was carried out, and the value of the displacement at break (breaking elongation) was used as an index of flexibility, which was evaluated according to the following criteria. <Evaluation criteria> ◎: Breaking elongation exceeds 1% when pulled at 1 mm / min. ○: Breaking elongation when pulled at 1 mm / min is more than 0.5% and 1% or less ×: Breaking elongation when pulled at 1 mm / min is 0.5% or less

[0117] ((6) Flexibility) The JIS No. 1 dumbbell test piece sheet was punched out from the press sheet used in the evaluation of (4) tensile strength above, and both ends of the sheet were overlapped to evaluate the flexibility. The evaluation criteria are shown below. <Evaluation criteria> ○: No breakage occurs even when both ends of the JIS No. 1 dumbbell test piece sheet are overlapped. ×: The JIS No. 1 dumbbell test piece breaks when both ends of the sheet are brought close together.

[0118] ((7) Mold shrinkage rate) A 100 mm diameter disk mold was heated to 175°C, and its inner diameter (D1) was measured. Using this mold, a molded article of the resin composition was produced at 175°C, with an injection pressure of 50 kgf / cm2 and a molding time of 2 minutes. After curing at 175°C for 8 hours, the diameter (D2) of the molded article was measured at room temperature (23°C). Using the values of D1 and D2, the molding shrinkage was calculated according to the following formula. Mold shrinkage rate (%) = ((D1-D2) / (D1)) x 100 <Evaluation criteria> ◎: 0.3% or less ○: Over 0.3% and 0.5% or less ×: More than 0.5%

[0119] [Table 4]

[0120] [Table 5]

[0121] [Table 6]

[0122] The evaluation results of Production Examples 1 to 10 using the block copolymers of Examples 1 to 10 revealed that block copolymers having polymer blocks (A) at both ends have strong cohesive forces between the polymer blocks (A), resulting in high strength. Furthermore, due to their high fluidity, they have excellent processability, and it was found that tough resin compositions could be produced without solvent.

[0123] The evaluation results of Production Examples 5 to 7 using the block copolymers of Examples 5 to 7 showed that resin compositions containing block copolymers having polymer blocks (A) at both ends and copolymer blocks (C) of styrene and butadiene could achieve high strength and low mold shrinkage. This is thought to be because the styrene blocks at both ends exhibit high cohesive strength, and the copolymer block (C) shifts the glass transition temperature to a higher temperature, thereby reducing mold shrinkage.

[0124] The evaluation results of Production Examples 8 to 10 using the block copolymers of Examples 8 to 10 suggested that introducing a butadiene block (B) with a high vinyl bond content into the polymer block (A) at both ends could achieve high strength and even higher fluidity. It is believed that the placement of a butadiene block with a high vinyl bond content inside shortens the apparent molecular chain, resulting in high fluidity. This allows the copolymer to melt easily even at relatively low processing temperatures of 130°C when blended with an epoxy resin, significantly improving processability.

[0125] The evaluation results of Production Examples 11 to 13 using the block copolymers of Examples 11 to 13 showed that a block structure of (A)-(C)-(B)-(A)-(B) results in a block copolymer that satisfies high fluidity, high strength, and flexibility. It is believed that the cohesive strength of polymer block (A) contributes to high strength, the internal polymer block (B) with a high vinyl bond content contributes to high fluidity, and the terminal polymer block (B) with a high vinyl bond content contributes to flexibility. This has been shown to improve processability during resin composition production and to impart excellent mechanical properties to the resin composition. Furthermore, the presence of polymer block (C) enables low molding shrinkage.

[0126] From Comparative Example 1, it can be seen that the block copolymer 16 composed only of the polymer block (A) is very rigid because it does not contain a flexible butadiene component. As can be seen from Comparative Production Example 1, it was found that it is difficult to impart flexibility to an epoxy resin.

[0127] The block copolymer 17 produced in Comparative Example 2 did not have the polymer block (A), and therefore had weak cohesive force, which reduced the effect of pseudo-crosslinking by the polymer block (A), and tended to result in reduced strength.

[0128] The block copolymer 18 produced in Comparative Example 3 has a two-stage block structure of (A)-(C), and therefore has a high melt flow rate and excellent processability. However, it was found that the strength was reduced compared to the block copolymers produced in the Examples because the cohesive strength of the polymer block (A) was low.

[0129] The block copolymer 19 produced in Comparative Example 4 has a structure in which the content of polymer block (A) is outside the range of the present invention. It was found that when the content of polymer block (A) is outside the upper limit of the present invention, the flexibility is significantly reduced, the flexibility of the epoxy resin is reduced, and the epoxy resin is easily broken.

[0130] The block copolymer 20 produced in Comparative Example 5 has a structure in which the hydrogenation degree is outside the lower limit of the present invention. It was found that when the hydrogenation degree is outside the lower limit, thermal oxidative degradation occurs starting from the double bonds derived from butadiene in the block copolymer during the curing process of the resin composition, causing the formation of a large amount of gel in the molded product.

[0131] The block copolymer 21 produced in Comparative Example 6 has a structure in which the molecular weight exceeds the upper limit of the present invention. Exceeding the upper limit of the molecular weight reduces the melt flow rate and also deviates from the range of the storage modulus difference G'. This significantly reduces the fluidity, and significantly deteriorates the processability during the production of the resin composition.

[0132] The block copolymer 22 produced in Comparative Example 7 has a structure in which the melt flow rate exceeds the upper limit of the present invention. When the melt flow rate exceeds the upper limit, the processability is improved, but the excessively low molecular weight prevents sufficient formation of microphase separation, resulting in a decrease in flexibility and mechanical properties.

[0133] Block copolymer 23 produced in Comparative Example 8 has a structure that does not have polar groups in the block copolymer molecule. In the present invention, the polar groups in the block copolymer react with the epoxy groups in the epoxy resin. This reaction strengthens the interfacial adhesion between the epoxy resin matrix and the block copolymer, which is the dispersed phase, thereby reducing the occurrence of cracks that can lead to fracture when fatigue is applied. It was found that when a structure that does not have polar groups, such as block copolymer 23, is used as a resin composition, the interfacial adhesive strength with the matrix decreases, easily leading to fracture.

[0134] (Manufacturing Examples 16 to 19) Resin compositions were produced in the same manner as in Production Examples 1 to 15 and Production Comparative Examples 1 to 8, except that the blending amounts of each component were changed as shown in Table 7 below, and the physical properties were evaluated in the same manner as in Production Examples 1 to 15 and Production Comparative Examples 1 to 8. The evaluation results are shown in Table 7.

[0135] [Table 7]

[0136] From Production Examples 16 to 19, it was found that as the amount of block copolymer added increased, the flexibility and elongation at break improved. On the other hand, the melt viscosity tended to decrease, so it was found that it was necessary to consider the balance with the mechanical properties. [Industrial Applicability]

[0137] The block copolymer and resin composition thereof of the present invention have industrial applicability in the fields of electronic materials such as semiconductor encapsulants, aerospace and sporting goods that use carbon fiber composite materials (CFRP).

Claims

1. A block copolymer (I) comprising an aromatic vinyl monomer unit and a conjugated diene monomer unit, A block copolymer (I) that satisfies the following conditions (a) to (e): (Condition (a)) The composition contains at least one polymer block (A) mainly composed of an aromatic vinyl monomer unit, and the content of the polymer block (A) is 10% by mass or more and 50% by mass or less. (Condition (b)) It contains a polymer block (B) mainly composed of conjugated diene monomer units. (Condition (C)) The hydrogenation rate of the conjugated diene monomer units is 20% or more and 100% or less. (Condition (D)) The melt flow rate under the conditions of JIS K7210, 230°C and a load of 2.16 kg is 100 to 300 g / 10 min. (Condition (e)) The storage modulus G' at 125°C in the viscoelasticity chart is 2.0 x 10 -1 It is less than MPa.

2. Contains at least one polymer block (C) consisting of an aromatic vinyl monomer unit and a conjugated diene monomer unit, the content of aromatic vinyl monomer units in the polymer block (C) is 5% by mass or more and 79% by mass or less of the total mass of the block copolymer (I); The block copolymer (I) according to claim 1.

3. the vinyl bond content of the conjugated diene monomer units in the block copolymer (I) is 30% by mass or more; The block copolymer (I) according to claim 1.

4. The weight average molecular weight Mw is less than 70,000. The block copolymer (I) according to claim 1.

5. the block copolymer (I) has, in its molecule, at least one polar group selected from the group consisting of an acid anhydride group, an amine group, a hydroxyl group, a carboxylic acid group, and an epoxy group; The block copolymer (I) according to claim 1.

6. the hydrogenation rate of the conjugated diene monomer units is 50% or more and 100% or less; The block copolymer (I) according to claim 1.

7. the content of the polymer block (A) mainly composed of aromatic vinyl monomer units in the block copolymer (I) is 15% by mass or more and 40% by mass or less; The block copolymer (I) according to claim 1.

8. JIS K7210, the melt flow rate under the conditions of 230°C and a load of 2.16 kg is 150 to 300 g / 10 min; The block copolymer (I) according to claim 1.

9. The block copolymer (I) according to any one of claims 1 to 8, a thermosetting resin (II); Contains the content of the block copolymer (I) is 1% by mass or more and 30% by mass or less, The resin composition, wherein the content of the thermosetting resin (II) is 70% by mass or more and 99% by mass or less.

10. The thermosetting resin (II) is an epoxy resin, and the softening point of the epoxy resin is 50°C or higher and 120°C or lower. The resin composition according to claim 9.

11. The epoxy resin is at least one epoxy resin selected from the group consisting of a naphthalene type, a cresol novolac type, and a dicyclopentadiene type. The resin composition according to claim 10.

12. Further containing a phenolic curing agent (III) and a curing accelerator (IV), the content of the block copolymer (I) is 1% by mass or more and 10% by mass or less, The content of the thermosetting resin (II) is 70% by mass or more and 80% by mass or less, The content of the phenol-based curing agent (III) is 10% by mass or more and 30% by mass or less, The content of the curing accelerator (IV) is 0.1% by mass or more and 5% by mass or less. The resin composition according to claim 9.

13. A molded article made from the resin composition according to claim 9.

14. The molded article according to claim 13, which is a semiconductor encapsulant.

15. A method for producing the resin composition according to claim 9, The method includes a step of mixing the block copolymer (I) and the thermosetting resin (II) without using a solvent. A method for producing a resin composition.

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