Resin composition and molded article

Abstract

This resin composition comprises block copolymers (II). The block copolymers (II) include a block copolymer (II-1) and a block copolymer (II-2). The block copolymer (II-1) is a triblock copolymer having a bonding form of polymeric block (A1)-polymeric block (B1)-polymeric block (A1'). The block copolymer (II-2) is a diblock copolymer having a bonding form of polymeric block (A2)-polymeric block (B2). The polymeric block (A1), the polymeric block (A1'), and the polymeric block (A2) are each a polymeric block including a structural unit derived from an aromatic vinyl compound. The polymeric block (B1) and the polymeric block (B2) are each a polymeric block including a structural unit derived from a conjugated diene compound. This molded article is formed from said resin composition.

Description

Resin composition and molded article

[0001] The present invention relates to resin compositions and molded articles.

[0002] Rubber compositions, which are mixtures of thermoplastic elastomers with various types of rubber, possess excellent mechanical properties and flexibility, and are therefore used in a wide range of applications, including shoe soles, various types of tires, building materials such as gaskets, and machine parts. However, rubber compositions containing thermoplastic elastomers become slippery when moisture adheres to them, which poses a significant safety risk, especially in applications such as shoe soles and various types of tires.

[0003] Therefore, studies are being conducted to improve the wet grip properties of rubber compositions containing thermoplastic elastomers and rubber components. For example, resin compositions that specify the number-average molecular weight of the thermoplastic elastomer, the glass transition temperature of the rubber component, etc., or resin compositions containing tackifying resins, hydrogenated block copolymers, etc. have been proposed (for example, Patent Documents 1 to 8). In addition, resin compositions containing hydrogenated block copolymers containing polymer blocks containing farnesene-derived structural units have been proposed (for example, Patent Documents 9 to 10).

[0004] U.S. Patent Application Publication No. 2013 / 0086822, Specification International Publication No. 2006 / 121069, JP 2017-39819, JP 2016-210937, JP 2014-189697, JP 2014-520017, JP 2004-75882, JP 2003-292672, JP 2019-26826, International Publication No. 2021 / 100738

[0005] However, the technologies disclosed in Patent Documents 1 to 10 made it difficult to achieve a higher level of both dry grip and wet grip while suppressing a decrease in wear resistance.

[0006] Therefore, the object of the present invention is to provide a resin composition capable of forming a molded article that has good wear resistance and achieves a high degree of both dry grip and wet grip, and a molded article of the resin composition.

[0007] As a result of diligent research to solve the above problems, the present inventors have come up with the present invention described below and have found that it can solve the problems. That is, the present invention is as follows.

[0008] [1] A resin composition comprising rubber (I) and a block copolymer (II), wherein the block copolymer (II) comprises a block copolymer (II-1) and a block copolymer (II-2), the block copolymer (II-1) is a triblock copolymer having a polymer block (A1)-polymer block (B1)-polymer block (A1') bonding structure, the block copolymer (II-2) is a diblock copolymer having a polymer block (A2)-polymer block (B2) bonding structure, the polymer block (A1), the polymer block (A1'), and the polymer block (A2) are polymer blocks containing structural units derived from aromatic vinyl compounds, and the polymer block (B1) and the polymer block (B2) are polymer blocks containing structural units derived from conjugated diene compounds. [2] The resin composition according to [1], wherein the structural units derived from the conjugated diene compound in the polymer block (B1) and the polymer block (B2) contain at least one selected from the group consisting of structural units derived from isoprene and structural units derived from butadiene. [3] The resin composition according to [1], wherein the structural units derived from the conjugated diene compound in the polymer block (B1) and the polymer block (B2) contain structural units derived from isoprene. [4] The resin composition according to any one of [1] to [3], wherein the mass ratio of the rubber (I) to the block copolymer (II) [(I) / (II)] is 45 / 55 or more and 99 / 1 or less. [5] The resin composition according to any one of [1] to [4], wherein the block copolymer (II) is a hydrogenated block copolymer. [6] The resin composition according to [5], wherein the hydrogenation rate of the carbon-carbon double bond in the structural unit derived from the conjugated diene compound in the block copolymer (II) is 94 mol% or more and 100 mol% or less. [7] The resin composition according to any one of [1] to [6] above, wherein the weight-average molecular weight (Mw) of the block copolymer (II-1) is 50,000 or more and 600,000 or less. [8] The resin composition according to any one of [1] to [7] above, wherein the weight-average molecular weight (Mw) of the block copolymer (II-2) is 10,000 or more and 150,000 or less.[9] The resin composition according to any one of [1] to [8] above, wherein the content of vinyl bond units in 100 mol% of the total structural units derived from the conjugated diene compound contained in the block copolymer (II) is 0 mol% or more and 50.0 mol% or less.

[10] The resin composition according to any one of [1] to [9] above, further containing a crosslinking agent.

[11] The resin composition according to

[10] above, wherein the crosslinking agent contains sulfur or a sulfur-containing compound.

[12] The resin composition according to any one of [1] to

[11] above, further containing silica, wherein the silica content is 1 part by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the total of the rubber (I) and the block copolymer (II).

[13] The resin composition according to any one of [1] to

[12] above, wherein the hardness measured at 23°C using a type A durometer in accordance with JIS K 6253-3:2023 is 50 or more and 80 or less.

[14] A resin composition according to any one of [1] to

[13] above, for use in tires.

[15] A resin composition according to any one of [1] to

[13] above, for use in footwear.

[16] A molded article of a resin composition according to any one of [1] to

[15] above.

[0009] According to the present invention, it is possible to provide a resin composition capable of forming a molded article that has good wear resistance and achieves a high degree of both dry grip and wet grip, and a molded article of the resin composition.

[0010] The following description is based on an example of an embodiment of the present invention. However, the embodiments shown below are illustrative examples for realizing the technical concept of the present invention, and the present invention is not limited to the following description. Embodiments in which any of the descriptions in this specification are arbitrarily selected or arbitrarily combined are also included in the present invention. In this specification, preferred provisions can be arbitrarily selected, and combinations of preferred provisions can be said to be more preferred. In this specification, the description "XX to YY" means "XX or more and YY or less". In this specification, the lower limit and upper limit values ​​described in steps for a preferred numerical range (for example, a range of content, etc.) can be combined independently. For example, from the description "preferably 10 or more and 90 or less, more preferably 30 or more and 60 or less", the "preferred lower limit (10)" and the "more preferred upper limit (60)" can be combined to get "10 or more and 60 or less". The same applies when the preferred numerical range is described as "XX to YY".

[0011] [Resin Composition] The resin composition of this embodiment contains rubber (I) and a block copolymer (II), wherein the block copolymer (II) contains a block copolymer (II-1) and a block copolymer (II-2), the block copolymer (II-1) is a triblock copolymer having a polymer block (A1)-polymer block (B1)-polymer block (A1') bonding structure, the block copolymer (II-2) is a diblock copolymer having a polymer block (A2)-polymer block (B2) bonding structure, the polymer block (A1), the polymer block (A1'), and the polymer block (A2) are polymer blocks containing structural units derived from aromatic vinyl compounds, and the polymer block (B1) and the polymer block (B2) are polymer blocks containing structural units derived from conjugated diene compounds.

[0012] The resin composition of this embodiment, having the above configuration, is a resin composition capable of forming molded articles that have good abrasion resistance and a high degree of balance between dry grip and wet grip. The details of the reason for this are unknown, but it is presumed that the following is the case. The diblock copolymer contained in block copolymer (II) has a low melt viscosity, which is thought to contribute to the good dispersion of block copolymer (II) in rubber (I). Therefore, in the molded article formed from the resin composition of this embodiment, block copolymer (II) is well dispersed in rubber (I), and it is thought that this resulted in a good improvement in grip due to the flexibility of block copolymer (II). In addition, since block copolymer (II) contains a triblock copolymer with a high molecular weight, it is presumed that the abrasion resistance of the molded article was well maintained. The components contained in the resin composition of this embodiment will be described below. In the following description, "dry grip and wet grip" may be simply referred to as "grip".

[0013] <Rubber (I)> Examples of rubber (I) include natural rubber and various synthetic rubbers. Note that block copolymer (II) is not included in rubber (I). Rubber (I) may be used alone or in combination of two or more types.

[0014] Examples of natural rubber (NR) include TSR (Technically Specified Rubber) such as SMR (Malaysian TSR), SIR (Indonesian TSR), and STR (Thai TSR), as well as RSS (Ribbed Smoked Sheet); high-purity natural rubber; modified natural rubber such as epoxidized natural rubber, hydroxylated natural rubber, hydrogenated natural rubber, and grafted natural rubber.

[0015] Examples of synthetic rubbers include styrene-butadiene copolymer rubber (SBR), polyisoprene rubber (IR), polybutadiene rubber (BR), acrylonitrile-butadiene copolymer rubber (NBR), ethylene-propylene-diene copolymer (EP), ethylene-propylene copolymer rubber (EPPM), ethylene-propylene-non-conjugated diene copolymer rubber (EPDM), butyl rubber (isobutylene-isoprene rubber) (IIR), and halogenated butyl rubber (halogenated IIR) obtained by modifying butyl rubber.

[0016] Among the above rubbers, NR, SBR, IR, BR, NBR, EP, EPM, EPDM, IIR, and halogenated IIR are preferred from the viewpoint of physical properties such as strength, abrasion resistance, elasticity, and flexibility, as well as compatibility with various components such as block copolymers (II). When two or more types of rubber (I) are used in combination, two or more selected from the group consisting of NR, SBR, and BR are preferred from the viewpoint of balancing grip, abrasion resistance, and mechanical properties.

[0017] Commercially available SBR can be used as the SBR, and any of the following can be used, for example, emulsion polymerized styrene-butadiene rubber (E-SBR), solution polymerized styrene-butadiene rubber (S-SBR), or modified styrene-butadiene rubber (modified SBR). The styrene unit content in 100% by mass of SBR is preferably 0.1% by mass or more and 80% by mass or less, more preferably 5% by mass or more and 70% by mass or less, even more preferably 10% by mass or more and 50% by mass or less, even more preferably 12% by mass or more and 35% by mass or less, and even more preferably 15% by mass or more and 25% by mass or less. SBR has a good balance of physical properties such as elasticity and strength, and is also suitable from the viewpoint of processability such as kneading and molding, and availability.

[0018] Commercially available IRs can be used as the IR, and for example, IRs with a high cis isomer content polymerized with a Ziegler catalyst and ultra-high cis isomer content IRs obtained using a lanthanide rare earth metal catalyst are preferred. The weight-average molecular weight (Mw) of the IR is preferably 90,000 to 2,000,000, more preferably 150,000 to 1,500,000. When the weight-average molecular weight (Mw) is within the above range, the formability and tensile properties are good. The weight-average molecular weight of the IR is the weight-average molecular weight on a polystyrene basis determined from gel permeation chromatography (GPC) measurements. The vinyl bond content of the IR (total content of 1,2-bonding units and 3,4-bonding units) is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, per 100% by mass of the IR. The IR has a good balance of physical properties such as strength and is also suitable from the viewpoint of availability.

[0019] Commercially available BR can be used as the BR. From the viewpoint of imparting excellent wear resistance to the molded resin composition, BR with a high cis isomer content polymerized with a Ziegler-type catalyst and BR with an ultra-high cis isomer content obtained using a lanthanide-type rare earth metal catalyst are preferred. From the viewpoint of imparting excellent processability to the molded resin composition, BR with a low cis isomer content is preferred. In addition, BR with a high cis isomer content and BR with a low cis isomer content may be used in combination. The weight-average molecular weight (Mw) of BR is preferably 90,000 to 2,000,000, more preferably 150,000 to 1,500,000, even more preferably 250,000 to 1,000,000, and even more preferably 350,000 to 700,000. When the weight-average molecular weight (Mw) is within the above range, the moldability and tensile properties are good. The weight-average molecular weight (Mw) of BR is the weight-average molecular weight in polystyrene terms, determined from gel permeation chromatography (GPC) measurements. The vinyl bond content (content of 1,2-bonding units) of BR is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, of 100% by mass of BR. BR is suitable from the viewpoint of imparting excellent abrasion resistance to molded articles of resin compositions.

[0020] Commercially available NBR can be used as the NBR. The acrylonitrile unit content is preferably 20% to 50% by mass, and more preferably 25% to 41% by mass, based on 100% by mass of NBR. When the acrylonitrile unit content is within the above range, it is expected that good grip and abrasion resistance will be imparted to the molded resin composition.

[0021] Commercially available EP, EPM, and EPDM can be used as EP, EPM, and EPDM. Examples of non-conjugated diene compounds constituting EPDM include 5-ethylidene-2-norbornene (ENB), 1,4-hexadiene, 5-methylene-2-norbornene (MNB), 1,6-octadiene, 5-methyl-1,4-hexadiene, 3,7-dimethyl-1,6-octadiene, 1,3-cyclopentadiene, 1,4-cyclohexadiene, tetrahydroindene, methyltetrahydroindene, dicyclopentadiene, 5-isopropylidene-2-norbornene, 5-vinyl-norbornene, dicyclooctadiene, and methylenenorbornene. Among these, 5-ethylidene-2-norbornene (ENB) is preferred from the viewpoint of vulcanization rate. Among EP, EPM, and EPDM, EPDM is preferred from the viewpoint of obtaining a higher vulcanization rate.

[0022] Examples of IIRs include non-halogenated butyl rubber and recycled butyl rubber. Halogenated IIRs are modified IIRs by introducing a halogen into the molecule, and examples include brominated butyl rubber (Br-IIR) and chlorinated butyl rubber (Cl-IIR). Brominated isobutylene-p-methylstyrene copolymers can also be used.

[0023] (Rubber (I) content) The rubber (I) content in 100% by mass of the resin composition of this embodiment is preferably 10% by mass or more and 95% by mass or less, more preferably 20% by mass or more and 90% by mass or less, even more preferably 30% by mass or more and 85% by mass or less, even more preferably 40% by mass or more and 80% by mass or less, even more preferably 45% by mass or more and 75% by mass or less, and particularly preferably 50% by mass or more and 70% by mass or less, from the viewpoint of achieving a good balance between grip and abrasion resistance.

[0024] <Block Copolymer (II)> The resin composition of this embodiment contains block copolymer (II). Note that rubber (I) is not included in block copolymer (II). Block copolymer (II) contains block copolymer (II-1) and block copolymer (II-2). Block copolymer (II-1) is a triblock copolymer having a bonding configuration of polymer block (A1) - polymer block (B1) - polymer block (A1'). Block copolymer (II-2) is a diblock copolymer having a bonding configuration of polymer block (A2) - polymer block (B2). In block copolymer (II-1), polymer block (A1), polymer block (B1), and polymer block (A1') may each be different blocks, or polymer block (A1) and polymer block (A1') may be the same block, and polymer block (B1) may be a different block from polymer block (A1) and polymer block (A1'). In block copolymer (II-2), polymer block (A2) and polymer block (B2) are different blocks. The block copolymer (II) may be an unhydrogenated block copolymer or a hydrogenated block copolymer, but it is preferably a hydrogenated block copolymer.

[0025] (Polymer block (A1), polymer block (A1'), and polymer block (A2)) Polymer block (A1), polymer block (A1'), and polymer block (A2) are polymer blocks containing structural units derived from aromatic vinyl compounds. Polymer block (A1), polymer block (A1'), and polymer block (A2) may be the same or different. The content of structural units derived from aromatic vinyl compounds in 100% by mass of polymer block (A1) is preferably 70% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, even more preferably 90% by mass or more and 100% by mass or less, even more preferably 95% by mass or more and 100% by mass or less, and even more preferably 100% by mass. The content of structural units derived from aromatic vinyl compounds in 100% by mass of polymer block (A1') is preferably 70% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, even more preferably 90% by mass or more and 100% by mass or less, even more preferably 95% by mass or more and 100% by mass or less, and even more preferably 100% by mass. The content of structural units derived from aromatic vinyl compounds in 100% by mass of polymer block (A2) is preferably 70% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, even more preferably 90% by mass or more and 100% by mass or less, even more preferably 95% by mass or more and 100% by mass or less, and even more preferably 100% by mass. Examples of aromatic vinyl compounds include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-t-butylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 2,4,6-trimethylstyrene, 2-ethyl-4-benzylstyrene, 4-(phenylbutyl)styrene, 1-vinylnaphthalene, 2-vinylnaphthalene, vinylanthracene, N,N-diethyl-4-aminoethylstyrene, vinylpyridine, 4-methoxystyrene, monochlorostyrene, dichlorostyrene, and divinylbenzene. These aromatic vinyl compounds may be used individually or in combination of two or more.The structural units derived from aromatic vinyl compounds are preferably at least one selected from the group consisting of styrene, α-methylstyrene, and 4-methylstyrene, and more preferably structural units derived from styrene. Polymer block (A1), polymer block (A1'), and polymer block (A2) preferably contain structural units derived from the same aromatic vinyl compound, and polymer block (A1), polymer block (A1'), and polymer block (A2) more preferably contain structural units derived from styrene.

[0026] Polymer blocks (A1), polymer block (A1'), and polymer block (A2) may contain structural units derived from monomers other than aromatic vinyl compounds. For example, they may contain structural units derived from conjugated diene compounds, etc., as contained in polymer block (B1) and polymer block (B2) described later. Polymer blocks (A1), polymer block (A1'), and polymer block (A2) do not have to contain structural units derived from monomers other than aromatic vinyl compounds; in other words, they may consist only of structural units derived from aromatic vinyl compounds.

[0027] (Polymer block (B1) and polymer block (B2)) Polymer block (B1) and polymer block (B2) are polymer blocks containing structural units derived from conjugated diene compounds. Polymer block (B1) and polymer block (B2) may be the same or different. The content of structural units derived from conjugated diene compounds in 100% by mass of polymer block (B1) is preferably 70% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, even more preferably 90% by mass or more and 100% by mass or less, even more preferably 95% by mass or more and 100% by mass or less, and even more preferably 100% by mass. The content of structural units derived from conjugated diene compounds in 100% by mass of polymer block (B2) is preferably 70% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, even more preferably 90% by mass or more and 100% by mass or less, even more preferably 95% by mass or more and 100% by mass or less, and even more preferably 100% by mass. Examples of conjugated diene compounds include isoprene, butadiene, farnesene, 2,3-dimethyl-butadiene, 2-phenyl-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 1,3-octadiene, 1,3-cyclohexadiene, 2-methyl-1,3-octadiene, 1,3,7-octatriene, myrcene, chloroprene, and the like. These conjugated diene compounds may be used individually or in combination of two or more. Among these, the structural unit derived from the conjugated diene compound preferably contains at least one selected from the group consisting of structural units derived from isoprene and structural units derived from butadiene, and more preferably contains structural units derived from isoprene.

[0028] Polymer blocks (B1) and (B2) may contain structural units derived from monomers other than conjugated diene compounds. For example, they may contain structural units derived from aromatic vinyl compounds, etc. Polymer blocks (B1) and (B2) do not have to contain structural units derived from monomers other than conjugated diene compounds; in other words, they may consist only of structural units derived from conjugated diene compounds.

[0029] The structural unit derived from the conjugated diene compound contained in the polymer block (B1) and the structural unit derived from the conjugated diene compound contained in the polymer block (B2) may be the same or different, and it is more preferable that they are the same. Specifically, it is more preferable that the structural unit derived from the conjugated diene compound contained in the polymer block (B1) contains a structural unit derived from isoprene and the structural unit derived from the conjugated diene compound contained in the polymer block (B2) contains a structural unit derived from isoprene, or that the structural unit derived from the conjugated diene compound contained in the polymer block (B1) contains a structural unit derived from butadiene and the structural unit derived from the conjugated diene compound contained in the polymer block (B2) contains a structural unit derived from butadiene. It is even more preferable that the structural unit derived from the conjugated diene compound contained in the polymer block (B1) contains only a structural unit derived from isoprene and the structural unit derived from the conjugated diene compound contained in the polymer block (B2) contains only a structural unit derived from isoprene, or that the structural unit derived from the conjugated diene compound contained in the polymer block (B1) contains only a structural unit derived from butadiene and the structural unit derived from the conjugated diene compound contained in the polymer block (B2) contains only a structural unit derived from butadiene.

[0030] When the polymer block (B1) and the polymer block (B2) contain a structural unit derived from butadiene, the bonding form thereof can be a 1,2-bond or a 1,4-bond. When the polymer block (B1) and the polymer block (B2) contain a structural unit derived from isoprene, the bonding form thereof can be a 1,2-bond, a 3,4-bond or a 1,4-bond. In this specification, the 3,4-bond unit and the 1,2-bond unit are referred to as vinyl bond units.

[0031] The content of vinyl bond units in the total 100 mol% of structural units derived from the conjugated diene compound contained in the block copolymer (II) (hereinafter also referred to as "vinyl bond amount") is preferably 0 mol% to 50.0 mol%, more preferably 1.0 mol% to 45.0 mol%, even more preferably 3.0 mol% to 40.0 mol%, and even more preferably 5.0 mol% to 40.0 mol%, from the viewpoint of achieving a good balance between grip and abrasion resistance. The vinyl bond amount is determined according to the method described in the examples. １ This value was calculated by 1H-NMR measurement.

[0032] (Block copolymer (II-1)) Block copolymer (II-1) is a triblock copolymer having a bonding configuration of polymer block (A1) - polymer block (B1) - polymer block (A1'). Block copolymer (II-1) may be used alone or in combination of two or more types.

[0033] In this specification, when identical polymer blocks are linearly linked via a divalent coupling agent or the like, the entire set of linked identical polymer blocks is treated as a single polymer block. For example, polymer block (A1) - polymer block (B1) - X - polymer block (B1) - polymer block (A1') (where X represents a coupling agent residue) is treated as a triblock copolymer having the linkage configuration of polymer block (A1) - polymer block (B1) - polymer block (A1').

[0034] [Weight-average molecular weight of polymer block (A1) and polymer block (A1') in block copolymer (II-1)] The weight-average molecular weight (Mw) of polymer block (A1) and polymer block (A1') contained in block copolymer (II-1) is preferably 1,000 or more and 100,000 or less, more preferably 2,000 or more and 50,000 or less, still more preferably 3,000 or more and 30,000 or less, even more preferably 4,000 or more and 15,000 or less, even more preferably 4,500 or more and 10,000 or less, and even more preferably 5,000 or more and 8,500 or less, respectively. The weight-average molecular weight (Mw) of polymer block (A1) and the weight-average molecular weight (Mw) of polymer block (A1') may be the same or different. When the weight-average molecular weight (Mw) of polymer block (A1) and polymer block (A1') is at least the above lower limit value, more excellent abrasion resistance is likely to be exhibited. Also, when the weight-average molecular weight (Mw) of polymer block (A1) and polymer block (A1') is at most the above upper limit value, more excellent grip performance is likely to be exhibited. The weight-average molecular weight (Mw) in this specification is the weight-average molecular weight in terms of polystyrene determined from measurement by gel permeation chromatography (GPC), and is the value measured by the method described in the examples below.

[0035] [Content of polymer block (A1) and polymer block (A1') in block copolymer (II-1)] The content of polymer block (A1) in 100% by mass of block copolymer (II-1) is preferably 0.5% by mass or more and 25% by mass or less, more preferably 1% by mass or more and 20% by mass or less, even more preferably 3% by mass or more and 15% by mass or less, and even more preferably 5% by mass or more and 10% by mass or less. When the content of polymer block (A1) is above the lower limit, better abrasion resistance is more likely to be exhibited. Also, when the content of polymer block (A1) is below the upper limit, better grip is more likely to be exhibited. The content of polymer block (A1') in 100% by mass of block copolymer (II-1) is preferably 0.5% by mass or more and 25% by mass or less, more preferably 1% by mass or more and 20% by mass or less, even more preferably 3% by mass or more and 15% by mass or less, and even more preferably 5% by mass or more and 10% by mass or less. When the content of polymer block (A1') is above the lower limit, superior abrasion resistance is more likely to be exhibited. Also, when the content of polymer block (A1') is below the upper limit, superior grip is more likely to be exhibited. The total content of polymer block (A1) and polymer block (A1') in 100% by mass of block copolymer (II-1) is preferably 1% by mass or more and 50% by mass or less, more preferably 3% by mass or more and 40% by mass or less, even more preferably 7% by mass or more and 30% by mass or less, and even more preferably 10% by mass or more and 20% by mass or less. When the total content of polymer block (A1) and polymer block (A1') is above the lower limit, superior abrasion resistance is more likely to be exhibited. Also, when the total content of polymer block (A1) and polymer block (A1') is below the upper limit, superior grip is more likely to be exhibited.

[0036] [Content of polymer block (B1) in block copolymer (II-1)] The content of polymer block (B1) in 100% by mass of block copolymer (II-1) is preferably 50% by mass or more and 99% by mass or less, more preferably 60% by mass or more and 97% by mass or less, even more preferably 70% by mass or more and 93% by mass or less, and even more preferably 80% by mass or more and 90% by mass or less. When the content of polymer block (B1) is above the lower limit, better grip performance is more likely to be exhibited. Also, when the content of polymer block (B1) is below the upper limit, better abrasion resistance is more likely to be exhibited.

[0037] [Mass ratio of polymer block (A1) and polymer block (A1') to polymer block (B1) in block copolymer (II-1)] The mass ratio of polymer block (A1) and polymer block (A1') to polymer block (B1) in block copolymer (II-1) [[(A1) + (A1')] / (B1)] is preferably 1 / 99 or more and 95 / 5 or less, more preferably 5 / 95 or more and 80 / 20 or less, even more preferably 7 / 93 or more and 50 / 50 or less, even more preferably 10 / 90 or more and 20 / 80 or less, and even more preferably 12 / 88 or more and 15 / 85 or less, from the viewpoint of achieving a good balance between grip and abrasion resistance.

[0038] [Weight-average molecular weight (Mw) and molecular weight distribution of block copolymer (II-1)] The weight-average molecular weight (Mw) of block copolymer (II-1) is preferably 50,000 to 600,000, more preferably 100,000 to 500,000, even more preferably 120,000 to 300,000, and even more preferably 150,000 to 250,000. When the weight-average molecular weight (Mw) of block copolymer (II-1) is above the lower limit, better abrasion resistance is more likely to be exhibited. Also, when the weight-average molecular weight (Mw) of block copolymer (II-1) is below the upper limit, better grip is more likely to be exhibited.

[0039] The molecular weight distribution (Mw / Mn) of the block copolymer (II-1) is preferably 1.0 to 6.0, more preferably 1.0 to 4.0, even more preferably 1.0 to 3.0, even more preferably 1.0 to 2.0, even more preferably 1.0 to 1.5, even more preferably 1.0 to 1.3, and even more preferably 1.0 to 1.1. When the molecular weight distribution is within the above range, the viscosity variation of the block copolymer (II-1) is small, making it easy to handle. The molecular weight distribution (Mw / Mn) in this specification is the value measured by the method described in the examples below.

[0040] (Block copolymer (II-2)) Block copolymer (II-2) is a diblock copolymer having a polymer block (A2) - polymer block (B2) bonding configuration. Block copolymer (II-2) may be used alone or in combination of two or more types.

[0041] [Molecular weight of polymer block (A2) in block copolymer (II-2)] The weight-average molecular weight (Mw) of the polymer block (A2) in the block copolymer (II-2) is preferably 800 to 50,000, more preferably 1,000 to 30,000, even more preferably 1,200 to 10,000, even more preferably 1,500 to 7,000, and even more preferably 1,700 to 6,000. When the weight-average molecular weight (Mw) of the polymer block (A2) is above the lower limit, better abrasion resistance is more likely to be exhibited. Also, when the weight-average molecular weight (Mw) of the polymer block (A2) is below the upper limit, better grip is more likely to be exhibited.

[0042] [Content of polymer block (A2) in block copolymer (II-2)] The content of polymer block (A2) in 100% by mass of block copolymer (II-2) is preferably 1% by mass or more and 50% by mass or less, more preferably 3% by mass or more and 40% by mass or less, even more preferably 7% by mass or more and 30% by mass or less, and even more preferably 10% by mass or more and 20% by mass or less. When the content of polymer block (A2) is above the lower limit, better abrasion resistance is more likely to be exhibited. Also, when the content of polymer block (A2) is below the upper limit, better grip is more likely to be exhibited.

[0043] [Content of polymer block (B2) in block copolymer (II-2)] The content of polymer block (B2) in 100% by mass of block copolymer (II-2) is preferably 50% by mass or more and 99% by mass or less, more preferably 60% by mass or more and 97% by mass or less, even more preferably 70% by mass or more and 93% by mass or less, and even more preferably 80% by mass or more and 90% by mass or less. When the content of polymer block (B2) is above the lower limit, better grip performance is more likely to be exhibited. Also, when the content of polymer block (B2) is below the upper limit, better abrasion resistance is more likely to be exhibited.

[0044] [Mass ratio of polymer block (A2) and polymer block (B2) in block copolymer (II-2)] The mass ratio [(A2) / (B2)] of polymer block (A2) and polymer block (B2) in block copolymer (II-2) is preferably 1 / 99 or more and 95 / 5 or less, more preferably 5 / 95 or more and 80 / 20 or less, even more preferably 10 / 90 or more and 50 / 50 or less, and even more preferably 12 / 88 or more and 20 / 80 or less, from the viewpoint of achieving a good balance between grip and abrasion resistance.

[0045] [Weight-average molecular weight (Mw) and molecular weight distribution of block copolymer (II-2)] The weight-average molecular weight (Mw) of block copolymer (II-2) is preferably 10,000 to 150,000, more preferably 30,000 to 100,000, even more preferably 32,000 to 90,000, even more preferably 36,000 to 80,000, and even more preferably 40,000 to 70,000, from the viewpoint of achieving a good balance between grip and abrasion resistance. When the weight-average molecular weight (Mw) of block copolymer (II-2) is above the lower limit, better abrasion resistance is more likely to be exhibited. Also, when the weight-average molecular weight (Mw) of block copolymer (II-2) is below the upper limit, better grip is more likely to be exhibited.

[0046] The molecular weight distribution (Mw / Mn) of the block copolymer (II-2) is preferably 1.0 to 6.0, more preferably 1.0 to 4.0, even more preferably 1.0 to 3.0, even more preferably 1.0 to 2.0, even more preferably 1.0 to 1.5, even more preferably 1.0 to 1.3, and even more preferably 1.0 to 1.1. When the molecular weight distribution is within the above range, the viscosity variation of the block copolymer (II-2) is small, making it easy to handle.

[0047] [Mass ratio of block copolymer (II-1) to block copolymer (II-2)] In block copolymer (II), the mass ratio of block copolymer (II-1) to block copolymer (II-2) [(II-1) / (II-2)] is preferably 5 / 95 or more and 95 / 5 or less, more preferably 10 / 90 or more and 90 / 10 or less, even more preferably 20 / 80 or more and 85 / 15 or less, and even more preferably 30 / 70 or more and 80 / 20 or less, from the viewpoint of achieving a good balance between grip and abrasion resistance.

[0048] The total content of block copolymer (II-1) and block copolymer (II-2) in 100% by mass of block copolymer (II) is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, even more preferably 95% by mass or more and 100% by mass or less, and even more preferably 100% by mass, from the viewpoint of achieving a good balance between grip and abrasion resistance.

[0049] (Method for producing block copolymer (II)) Block copolymer (II) can be produced by solution polymerization or by methods described in Japanese Patent Publication No. 2012-502135, Japanese Patent Publication No. 2012-502136, etc. Among these, solution polymerization is preferred. As for solution polymerization, known methods such as anionic polymerization, cationic polymerization, and other ionic polymerization methods; radical polymerization; etc. can be applied. Among these, anionic polymerization is preferred.

[0050] An anionic polymerization method involves sequentially adding aromatic vinyl compounds and conjugated diene compounds in the presence of a solvent, an anionic polymerization initiator, and optionally a Lewis base to obtain a block copolymer. Examples of anionic polymerization initiators include alkali metals such as lithium, sodium, and potassium; alkaline earth metals such as beryllium, magnesium, calcium, strontium, and barium; lanthanide rare earth metals such as lanthanum and neodymium; compounds containing the alkali metals, compounds containing the alkaline earth metals, and compounds containing lanthanide rare earth metals. Among these, compounds containing alkali metals and compounds containing alkaline earth metals are preferred, and compounds containing alkali metals are more preferred. Among the alkali metal-containing compounds, organoalkali metal compounds are preferred.

[0051] Examples of organoalkali metal compounds include organolithium compounds such as methyllithium, ethyllithium, n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, stilbenithium, dilithithiomethane, dilithionaphthalene, 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, and 1,3,5-trilithiobenzene; sodium naphthalene, potassium naphthalene; and others. Among these, organolithium compounds are preferred, with n-butyllithium and sec-butyllithium being more preferred, and sec-butyllithium being even more preferred. The organoalkali metal compounds may also be reacted with secondary amines such as diisopropylamine, dibutylamine, dihexylamine, and dibenzylamine to form organoalkali metal amides. The amount of organoalkali metal compound used varies depending on the molecular weight of the target block copolymer (II), but is usually 0.01 parts by mass to 3 parts by mass per 100 parts by mass of the total amount of aromatic vinyl compound and conjugated diene compound.

[0052] There are no particular restrictions on the solvent as long as it does not adversely affect the anionic polymerization reaction. Examples include saturated aliphatic hydrocarbons such as n-pentane, isopentane, n-hexane, n-heptane, and isooctane; saturated alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane; and aromatic hydrocarbons such as benzene, toluene, and xylene. These may be used individually or in combination of two or more. There are no particular restrictions on the amount of solvent used.

[0053] Lewis bases play a role in controlling the microstructure of structural units derived from conjugated diene compounds. Examples of Lewis bases include ether compounds such as dibutyl ether, diethyl ether, tetrahydrofuran, dioxane, and ethylene glycol diethyl ether; pyridine; tertiary amines such as N,N,N',N'-tetramethylethylenediamine and trimethylamine; alkali metal alkoxides such as potassium t-butoxide; and phosphine compounds. When using Lewis bases, the amount is usually preferably 0.01 to 1000 molar equivalents per mole of anionic polymerization initiator.

[0054] The polymerization reaction temperature is typically -80 to +150°C, preferably 0 to 100°C, and more preferably 10 to 90°C. The polymerization reaction may be batch-type or continuous-type. Block copolymer (II) can be produced by continuously or intermittently supplying each monomer to the polymerization reaction solution so that the amounts of aromatic vinyl compounds and conjugated diene compounds in the polymerization reaction system are within a specific range, or by sequentially polymerizing each monomer in the polymerization reaction solution so that the amounts of each monomer are in a specific ratio. The polymerization reaction can be stopped by adding an alcohol such as methanol or isopropanol as a polymerization stopper. Block copolymer (II) can be isolated by pouring the obtained polymerization reaction solution into a poor solvent such as methanol to precipitate the block copolymer, or by washing the polymerization reaction solution with water, separating it, and drying it.

[0055] Block copolymer (II-1), which is a triblock copolymer, is preferably produced by the method described in [i] or [ii] below. [i] A method of polymerizing polymer block (A1), polymer block (B1), and polymer block (A1') in this order. [ii] A method of producing the product by synthesizing a diblock copolymer of polymer block (A1) and polymer block (B1), and coupling the ends of the polymer block (B1) of the diblock copolymer using a coupling agent.

[0056] The block copolymer (II-2), which is a diblock copolymer, is preferably produced by polymerizing polymer block (A2) and polymer block (B2) in that order.

[0057] Examples of coupling agents include: divinylbenzene; polyvalent epoxy compounds such as epoxidized 1,2-polybutadiene, epoxidized soybean oil, and tetraglycidyl-1,3-bisaminomethylcyclohexane; halides such as tin tetrachloride, tetrachlorosilane, trichlorosilane, trichloromethylsilane, dichlorodimethylsilane, and dibromodimethylsilane; methyl benzoate, ethyl benzoate, phenyl benzoate, diethyl oxalate, diethyl malonate, diethyl adipate, dimethyl phthalate, and tetraglycidyl hydroxypropyl Examples include ester compounds such as dimethyl lephthalate; carbonate ester compounds such as dimethyl carbonate, diethyl carbonate, and diphenyl carbonate; alkoxysilane compounds such as diethoxydimethylsilane, trimethoxymethylsilane, triethoxymethylsilane, tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, tetrakis(2-ethylhexyloxy)silane, bis(triethoxysilyl)ethane, and 3-aminopropyltriethoxysilane; and 2,4-tolylene diisocyanate. These coupling agents may be used individually or in combination of two or more. Halides are preferred as coupling agents, halogenated silanes are more preferred, and dichlorodimethylsilane is even more preferred.

[0058] Block copolymer (II-1) and block copolymer (II-2) may be manufactured separately. Specifically, a polymerization reaction solution containing block copolymer (II-1) and a polymerization reaction solution containing block copolymer (II-2) may be prepared separately, and then block copolymer (II-1) and block copolymer (II-2) may be mixed. The mixing may be done by mixing the polymerization reaction solutions together, or by isolating block copolymer (II-1) and block copolymer (II-2) using the method described above before mixing. When the polymerization reaction solutions are mixed together, a mixture of block copolymer (II-1) and block copolymer (II-2) can be obtained by isolating the block copolymer using the method described above afterward. When block copolymer (II-1) and block copolymer (II-2) are isolated and then mixed, they may be mixed when mixing with rubber (I), or before mixing with rubber (I). As a mixing method, the method of mixing rubber (I) and block copolymer (II) described later can be applied.

[0059] Block copolymer (II-1) and block copolymer (II-2) may be produced in the same polymerization reaction solution. A polymerization reaction solution containing block copolymer (II-2) can be prepared first, and a portion of the total amount of block copolymer (II-2) contained in the polymerization reaction solution can be coupled using a coupling agent to obtain a polymerization reaction solution containing block copolymer (II-1) and block copolymer (II-2). Subsequently, a mixture of block copolymer (II-1) and block copolymer (II-2) can be obtained by isolating the block copolymer using the method described above. In this case, the polymerized block (A1) and polymerized block (A1') of block copolymer (II-1) and the polymerized block (A2) of block copolymer (II-2) are the same, and the polymerized block (B1) of block copolymer (II-1) and the polymerized block (B2) of block copolymer (II-2) are the same.

[0060] In this embodiment, the block copolymer (II) is preferably a hydrogenated block copolymer (II). A known method can be used for hydrogenation. For example, a hydrogenation reaction can be carried out by adding a Ziegler catalyst, a nickel, platinum, palladium, ruthenium, or rhodium metal catalyst supported on carbon, silica, diatomaceous earth, etc., or an organometallic complex having cobalt, nickel, palladium, rhodium, or ruthenium metal, to a solution obtained by dissolving the block copolymer (II) in a solvent that does not affect the hydrogenation reaction. Among these, palladium carbon, in which palladium is supported on carbon, is preferred as the hydrogenation catalyst. Hydrogenation may also be carried out by adding the hydrogenation catalyst to a polymerization reaction solution containing the block copolymer (II) obtained by the above-described method for producing the block copolymer (II). In the hydrogenation reaction, the hydrogen pressure is preferably 0.1 to 20 MPa, the reaction temperature is preferably 100 to 200°C, and the reaction time is preferably 1 to 20 hours.

[0061] The hydrogenation rate of the carbon-carbon double bond in the structural unit derived from the conjugated diene compound in the block copolymer (II) is preferably 94 mol% to 100 mol%, more preferably 95 mol% to 100 mol%, even more preferably 96 mol% to 100 mol%, even more preferably 97 mol% to 100 mol%, and even more preferably 98 mol% to 99.5 mol%, from the viewpoint of obtaining better grip. The hydrogenation rate is measured by the method described in the examples.

[0062] (Content of block copolymer (II)) The content of block copolymer (II) in 100% by mass of the resin composition of this embodiment is preferably 0.5% by mass or more and 50% by mass or less, more preferably 1% by mass or more and 40% by mass or less, even more preferably 2% by mass or more and 30% by mass or less, even more preferably 3% by mass or more and 25% by mass or less, and even more preferably 5% by mass or more and 20% by mass or less, from the viewpoint of achieving a good balance between grip and abrasion resistance.

[0063] The mass ratio [(I) / (II)] of rubber (I) to block copolymer (II) in the resin composition of this embodiment is preferably 45 / 55 to 99 / 1, more preferably 50 / 50 to 98 / 2, even more preferably 60 / 40 to 97 / 3, and even more preferably 70 / 30 to 96 / 4, from the viewpoint of achieving a good balance between grip and abrasion resistance. The total content of rubber (I) and block copolymer (II) in 100% by mass of the resin composition of this embodiment is preferably 45% to 85% by mass, more preferably 50% to 80% by mass, even more preferably 55% to 75% by mass, even more preferably 60% to 72% by mass, and even more preferably 65% ​​to 70% by mass.

[0064] <Crosslinking Agent> The resin composition of this embodiment preferably further contains a crosslinking agent. The crosslinking agent is preferably one that crosslinks only the carbon-carbon double bond or its α-methylene in the structural unit derived from the conjugated diene compound. Here, α-methylene refers to the methylene adjacent to the carbon-carbon double bond. By including such a crosslinking agent, only the carbon-carbon double bond or the α-methylene of the carbon-carbon double bond in the block copolymer (II) (or the one remaining in the copolymer in the case of a hydrogenated block copolymer) is crosslinked, making it possible to maintain excellent flexibility while providing excellent grip and abrasion resistance, and good tensile properties can also be expected.

[0065] Examples of crosslinking agents include sulfur; sulfur-containing compounds; radical generators; phenolic resins such as alkylphenol resins and brominated alkylphenol resins; combinations of p-quinone dioxime and lead dioxide, and combinations of p,p'-dibenzoylquinone dioxime and trilead tetroxide. Among these, from the viewpoint of tensile properties, the crosslinking agent preferably contains sulfur or a sulfur-containing compound, and more preferably contains sulfur. One type of crosslinking agent may be used alone, or two or more types may be used in combination.

[0066] Examples of sulfur include finely powdered sulfur, precipitated sulfur, colloidal sulfur, and insoluble sulfur. Examples of sulfur-containing compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, and triazinethiols.

[0067] Examples of radical generators include organic peroxides such as dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyn-3, 1,3-bis(t-butylperoxyisopropyl)benzene, α,α'-bis(t-butylperoxy)diisopropylbenzene, 3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(t-butylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, t-butylperoxybenzoate, t-butylperoxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, and t-butylcumyl peroxide.

[0068] The crosslinking agent content is preferably 0.1 parts by mass or more and 10.0 parts by mass or less, more preferably 0.5 parts by mass or more and 6.0 parts by mass or less, even more preferably 0.8 parts by mass or more and 4.0 parts by mass or less, even more preferably 0.8 parts by mass or more and 3.0 parts by mass or less, even more preferably 1.0 part by mass or more and 2.5 parts by mass or less, and even more preferably 1.2 parts by mass or more and 2.0 parts by mass or less, from the viewpoint of being able to express grip, abrasion resistance, flexibility and tensile properties in a good balance with 100 parts by mass of the total content of rubber (I) and block copolymer (II). The crosslinking agent content in 100% by mass of the resin composition of this embodiment is preferably 0.1% by mass or more and 10.0% by mass or less, more preferably 0.5% by mass or more and 6.0% by mass or less, even more preferably 0.8% by mass or more and 4.0% by mass or less, even more preferably 1.0% by mass or more and 2.5% by mass or less, even more preferably 1.0% by mass or more and 2.0% by mass or less, and even more preferably 1.0% by mass or more and 1.5% by mass or less.

[0069] <Crosslinking accelerator> The resin composition of this embodiment may contain a crosslinking accelerator. Examples of crosslinking accelerators include thiazoles such as N-cyclohexyl-2-benzothiazole sulfenamide, N,N-diisopropyl-2-benzothiazole sulfenamide, 2-mercaptobenzothiazole, dibenzothiazole disulfide, and 2-(4-morpholinodithio)benzothiazole; guanidines such as diphenylguanidine and triphenylguanidine; aldehyde-amine reactions or aldehyde-ammonia reactions such as butyraldehyde-aniline reaction product and hexamethylenetetramine-acetaldehyde reaction product; imidazolines such as 2-mercaptoimidazoline; thiocarbanilide, diethylurea, Examples include thioureas such as dibutylthiourea, trimethylthiourea, and diorthotolylthiourea; thiram monosulfides or thiram polysulfides such as tetramethylthiram monosulfide, tetramethylthiram disulfide, tetrabutylthiram disulfide, and pentamethylenethiram tetrasulfide; thiocarbamates such as zinc dimethyldithiocarbamate, zinc ethylphenyldithiocarbamate, sodium dimethyldithiocarbamate, selenium dimethyldithiocarbamate, and tellurium diethyldithiocarbamate; xanthogenic salts such as zinc dibutylxanthonate; and salicylic acid. A crosslinking accelerator may be used alone or in combination of two or more.

[0070] The content of the crosslinking accelerator is preferably 0.05 parts by mass or more and 15.0 parts by mass or less, more preferably 0.1 parts by mass or more and 5.0 parts by mass or less, still more preferably 0.3 parts by mass or more and 3.0 parts by mass or less, even more preferably 0.4 parts by mass or more and 2.5 parts by mass or less, even more preferably 0.5 parts by mass or more and 2.0 parts by mass or less, with respect to 100 parts by mass of the total content of the rubber (I) and the block copolymer (II). The content of the crosslinking accelerator in 100% by mass of the resin composition of the present embodiment is preferably 0.1% by mass or more and 10.0% by mass or less, more preferably 0.2% by mass or more and 5.0% by mass or less, still more preferably 0.3% by mass or more and 3.0% by mass or less, even more preferably 0.4% by mass or more and 2.5% by mass or less, even more preferably 0.5% by mass or more and 2.0% by mass or less, even more preferably 0.6% by mass or more and 1.0% by mass or less.

[0071] <Filler> The resin composition of the present embodiment preferably contains a filler. Examples of the filler include wet silica (hydrous silicic acid); dry silica (anhydrous silicic acid); silicate compounds such as calcium silicate, aluminum silicate, kaolin, talc, clay, pyrophyllite, mica, montmorillonite, bentonite, wollastonite, sepiolite, zonnolite, zeolite, diatomaceous earth, halloysite, etc. Among these, silica is preferable, and wet silica is more preferable, from the viewpoints of further improving the molding processability, the mechanical strength and wear resistance of the obtained molded body, and further improving the grip property. The filler may be used alone or in combination of two or more kinds.

[0072] The specific surface area of the silica is preferably 20 m ２ / g or more and 500 m ２ / g or less, more preferably 50 m ２ / g or more and 500 m ２ / g or less, still more preferably 100 m ２ / g or more and 300 m ２ / g or less, even more preferably 150 m ２ / g or more and 300 m ２It is less than / g. The specific surface area of ​​the above silica can be measured by the BET method using nitrogen as the carrier gas, in accordance with ISO 9277:2010.

[0073] From the viewpoint of achieving a good balance between grip and abrasion resistance, the silica content is preferably 1 to 60 parts by mass, more preferably 10 to 55 parts by mass, even more preferably 20 to 50 parts by mass, and even more preferably 25 to 45 parts by mass, per 100 parts by mass of the total of rubber (I) and block copolymer (II). The silica content in 100% by mass of the resin composition of this embodiment is preferably 1% to 55% by mass, more preferably 5% to 50% by mass, even more preferably 10% to 45% by mass, even more preferably 15% to 40% by mass, and even more preferably 20% to 35% by mass.

[0074] <Silane Coupling Agent> The resin composition of this embodiment preferably contains a silane coupling agent. Examples of silane coupling agents include sulfide compounds, mercapto compounds, vinyl compounds, amino compounds, glycidoxy compounds, nitro compounds, chloro compounds, and the like. One silane coupling agent may be used alone, or two or more may be used in combination. From the viewpoint of reactivity with silica, the silane coupling agent preferably has an alkoxysilyl group. Among the silane coupling agents having an alkoxysilyl group, methoxysilane and ethoxysilane are preferred.

[0075] Examples of sulfide compounds include bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(3-triethoxysilylpropyl) trisulfide, bis(3-trimethoxysilylpropyl) trisulfide, bis(3-triethoxysilylpropyl) disulfide, bis(3-trimethoxysilylpropyl) disulfide, and 3-trimethoxysilylpropyl Examples include lylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, and 3-trimethoxysilylpropyl methacrylate monosulfide.

[0076] Examples of mercapto compounds include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyl-di(tridecane-1-oxy-13-penta(ethylene oxide))ethoxysilane, 2-mercaptoethyltrimethoxysilane, and 2-mercaptoethyltriethoxysilane.

[0077] Examples of vinyl compounds include vinyltriethoxysilane and vinyltrimethoxysilane.

[0078] Examples of amino compounds include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, and 3-(2-aminoethyl)aminopropyltrimethoxysilane.

[0079] Examples of glycidoxy compounds include γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and γ-glycidoxypropylmethyldimethoxysilane.

[0080] Examples of nitro compounds include 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane.

[0081] Examples of chloro compounds include 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, and 2-chloroethyltriethoxysilane.

[0082] Among these silane coupling agents, bis(3-triethoxysilylpropyl) disulfide, bis(3-triethoxysilylpropyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, and 3-mercaptopropyltriethoxysilane are preferred from the viewpoint of wear resistance.

[0083] The content of the silane coupling agent is preferably 0.01 parts by mass to 30 parts by mass, more preferably 0.1 parts by mass to 25 parts by mass, even more preferably 1 part by mass to 20 parts by mass, even more preferably 3 parts by mass to 15 parts by mass, and even more preferably 5 parts by mass to 10 parts by mass, per 100 parts by mass of silica. When the content of the silane coupling agent is within the above range, the dispersibility of silica in the resin composition is good, and the wear resistance of the molded article tends to improve further.

[0084] <Other Fillers> The resin composition of this embodiment may contain other fillers other than those described above. These other fillers may be inorganic fillers or organic fillers. These other fillers may be used individually or in combination of two or more.

[0085] As the inorganic filler, at least one selected from metal oxides, metal carbonates, and carbon fibers is preferred. Examples of metal oxides include titanium oxide, iron oxide, magnesium oxide, aluminum oxide, cerium oxide, antimony oxide, tin oxide, lead oxide, chromium oxide, cobalt oxide, tungsten oxide, and copper oxide. Examples of metal carbonates include calcium carbonate and magnesium carbonate.

[0086] Examples of organic fillers include particulate organic fillers and fibrous organic fillers. Examples of particulate organic fillers include urethane microparticles, acrylic microparticles, styrene microparticles, acrylic / styrene-based microparticles, styrene-olefin microparticles, fluorine-based microparticles, polyethylene-based microparticles, and silicone microparticles. Examples of fibrous organic fillers include synthetic fibers such as 6-nylon fibers, 6,6-nylon fibers, 4,6-nylon fibers, aromatic polyamide fibers, para-aramid fibers, meta-aramid fibers, polyethylene terephthalate (PET) fibers, polyethylene naphthalate (PEN) fibers, poly-paraphenylene benzoxazole (PBO) fibers, PVA fibers (Vinylon), polyarylene sulfide fibers, 2,6-hydroxynaphthoic acid / para-hydroxybenzoic acid fibers (Vectran), polyethylene (PE) fibers, polypropylene (PP) fibers, polylactic acid (PLA) fibers, polybutylene succinate (PBS) fibers, polyethylene succinate fibers, syndiotactic-1,2-polybutadiene (SPB) fibers, and polyvinyl chloride (PVC) fibers; and natural (regenerated) fibers such as cotton, linen, rayon, and cellulose fibers.

[0087] <Tackifying Resin> The resin composition of this embodiment may or may not contain a tackifying resin. From the viewpoint of easily obtaining good abrasion resistance and easily obtaining good hardness, the resin composition of this embodiment may not contain a tackifying resin, or if it does contain one, the total content of the tackifying resin is preferably less than 5 parts by mass, more preferably 4 parts by mass or less, even more preferably 3 parts by mass or less, even more preferably 2 parts by mass or less, and even more preferably 1 part by mass or less, per 100 parts by mass of rubber (I). Examples of tackifying resins include one or more selected from the group consisting of terpene resins and aliphatic petroleum resins. The softening point of one or more selected from the group consisting of terpene resins and aliphatic petroleum resins is, for example, 50 to 180°C.

[0088] <Other Additives> The resin composition of this embodiment may contain other additives other than those described above, as long as they do not impair the effects of the present invention. Examples of other additives include heat aging inhibitors, antioxidants, light stabilizers, antistatic agents, mold release agents, flame retardants, foaming agents, pigments, dyes, whitening agents, liquid polydienes and their hydrogenated products. Examples of liquid polydienes and their hydrogenated products include liquid polybutadiene, liquid polyisoprene, liquid isoprene / butadiene copolymer, liquid styrene / butadiene copolymer, and liquid styrene / isoprene copolymer. These additives may be used individually or in combination of two or more.

[0089] <Method for Manufacturing the Resin Composition> The resin composition of this embodiment can be manufactured, for example, by melt-kneading each component except for the crosslinking agent and crosslinking accelerator, then adding the crosslinking agent and crosslinking accelerator and crosslinking. There are no particular restrictions on the method of melt-kneading each component except for the crosslinking agent and crosslinking accelerator. One method is to simultaneously supply rubber (I), block copolymer (II), and other optional components to a kneading device, such as a single-screw extruder, multi-screw extruder, Banbury mixer, Brabender mixer, open roll, heated roll, various kneaders, etc., and melt-knead them. Alternatively, the rubber (I), block copolymer (II), and other optional components may be supplied from separate inputs and melt-kneaded, or the block copolymer (II) and some optional components such as silica and silane coupling agents may be melt-kneaded in advance, and then the melt-kneaded mixture may be melt-kneaded with the other components. The temperature during melt-kneading can usually be arbitrarily selected within the range of 20 to 270°C.

[0090] One crosslinking method involves adding a crosslinking agent and, if necessary, a crosslinking accelerator after the melt-kneading described above, and then crosslinking using a vulcanizing mold at a vulcanizing temperature of typically 120 to 200°C, preferably 140 to 200°C, and a vulcanizing pressure of typically 0.5 to 10 MPa, which is maintained for typically 1 minute to 2 hours.

[0091] <Physical Properties> (Grip Properties) The static friction coefficient of a molded article obtained from the resin composition of this embodiment under dry conditions is preferably 6.0 or higher, more preferably 7.0 or higher, even more preferably 7.3 or higher, and even more preferably 7.7 or higher. A higher static friction coefficient under dry conditions is preferable, but it may be 20.0 or lower, or 15.0 or lower. The static friction coefficient under dry conditions is preferably 6.0 or higher and 20.0 or lower, more preferably 7.0 or higher and 20.0 or lower, even more preferably 7.3 or higher and 15.0 or lower, and even more preferably 7.7 or higher and 15.0 or lower. The static friction coefficient of a molded article obtained from the resin composition of this embodiment under wet conditions is preferably 3.5 or higher, more preferably 4.0 or higher, even more preferably 4.5 or higher, even more preferably 5.0 or higher, and even more preferably 5.5 or higher. A higher static friction coefficient under wet conditions is preferable, but it may be 15.0 or lower, or 10.0 or lower. The static friction coefficient under wet conditions is preferably 3.5 to 15.0, more preferably 4.0 to 15.0, even more preferably 4.5 to 15.0, even more preferably 5.0 to 10.0, and even more preferably 5.5 to 10.0. The static friction coefficient under dry and wet conditions is measured using a molded article that is crosslinked by 90% or more, by the method described in the examples. In this specification, the degree of crosslinking is confirmed using a vulcanization tester, Curlastometer®.

[0092] (Abrasion Resistance) The amount of abrasion of a molded article obtained from the resin composition of this embodiment, as measured by a DIN abrasion test (rotating cylindrical abrasion tester) in accordance with JIS K 6264-2:2005, is preferably 150 mm. ３ More preferably, 130 mm ３ Further preferably, 115 mm ３ More preferably, 110 mm ３ The following applies. A smaller amount of wear is preferable, but 50 mm ３ It may be greater than or equal to 70 mm ３ The above wear amount may be greater than or equal to 50 mm. ３ 150mm or more ３ More preferably 50 mm３ 130mm or more ３ Further preferably, 70 mm ３ 115mm or more ３ More preferably, 70 mm ３ 110mm or more ３ The following applies. The amount of wear is measured using a molded body that is cross-linked by 90% or more, by the method described in the examples.

[0093] (Hardness) The hardness of the molded article obtained from the resin composition of this embodiment at 23°C, measured by a Type A durometer of JIS K 6253-3:2023 (hereinafter also referred to as "A hardness"), is preferably 50 to 80, more preferably 53 to 76, even more preferably 57 to 73, and even more preferably 60 to 70. When the A hardness is within the above range, the moldability is good, and the good flexibility leads to high frictional force, resulting in excellent grip and wear resistance. The above hardness is measured using a molded article that is crosslinked by 90% or more, by the method described in the example.

[0094] (Tensile Breaking Strength) The tensile strength at break (tensile breaking strength) of the molded article obtained from the resin composition of this embodiment, as measured in accordance with JIS K 6251:2023, is preferably 5.0 MPa or higher, more preferably 10.0 MPa or higher, even more preferably 15.0 MPa or higher, and even more preferably 20.0 MPa or higher. A higher tensile breaking strength is preferable, but it may be 40.0 MPa or lower, or 30.0 MPa or lower. The above tensile breaking strength is preferably 5.0 MPa or higher and 40.0 MPa or lower, more preferably 10.0 MPa or higher and 40.0 MPa or lower, even more preferably 15.0 MPa or higher and 30.0 MPa or lower, and even more preferably 20.0 MPa or higher and 30.0 MPa or lower. The above tensile breaking strength is measured using a molded article that is 90% or more crosslinked, by the method described in the example.

[0095] (Tensile Elongation at Break) The elongation at break (tensile elongation at break) of a molded article obtained from the resin composition of this embodiment, measured in accordance with JIS K 6251:2023, is preferably 100% or more, more preferably 300% or more, even more preferably 500% or more, and even more preferably 600% or more. A higher tensile elongation at break is preferable, but it may be 1,000% or less, or 800% or less. The above tensile elongation at break is preferably 100% or more and 1,000% or less, more preferably 300% or more and 1,000% or less, even more preferably 500% or more and 800% or less, and even more preferably 600% or more and 800% or less. The above tensile elongation at break is measured using a molded article that is crosslinked by 90% or more, by the method described in the example.

[0096] <Applications of the Resin Composition> The resin composition of this embodiment has good abrasion resistance and can form molded articles that have a high degree of both dry grip and wet grip, making it suitable for the manufacture of molded articles that require these properties. Examples of molded articles made from the resin composition include the same ones as the examples of molded articles of this embodiment described later. Among these, the resin composition of this embodiment is preferably for tires or footwear.

[0097] [Molded Article] The molded article of this embodiment is a molded article of the resin composition of this embodiment. The molded article can be obtained by molding the resin composition of this embodiment into a desired shape using a desired manufacturing method. The shape of the molded article is not particularly limited as long as it is a molded article that can be manufactured using the resin composition of this embodiment, and can be molded into various shapes such as pellets, films, sheets, plates, pipes, tubes, rods, granules, etc. The method of manufacturing the molded article is not particularly limited and can be molded by various conventional molding methods such as injection molding, blow molding, press molding, extrusion molding, calendering, etc. The molded article of the resin composition of this embodiment can be suitably obtained as a press-molded article.

[0098] The molded articles of this embodiment have good wear resistance and achieve a high degree of balance between dry grip and wet grip, making them suitable for molded articles where these characteristics are required. Specifically, they are suitable for soles of footwear such as hiking boots, sandals, safety shoes, mountaineering boots, marathon shoes, tabi boots, and rubber boots; sports equipment such as swimming goggles, snorkels, ski boots, and skis / snowboards; writing instruments such as pens and scissors; tools and power tools such as screwdrivers, pliers, and wrenches; water-related items such as toothbrushes and kitchen utensils (knives, spatulas, etc.); sports and fitness equipment such as golf clubs, ski poles, bicycles, and motorcycles; various grips for knives, etc.; parts for home appliances such as refrigerators, vacuum cleaners, and waterproof bodies (mobile phones, etc.); side moldings, rack / opinion boots, suspension boots, etc. It can be suitably used in automotive parts such as quick-release joint boots, weatherstrips, mudguards, floor mats, armrests, beltline moldings, flush mounts, and automotive interior and exterior parts (gears, knobs, etc.); tread components for tires, especially winter tires, studless tires, all-season tires, fuel-efficient tires, and heavy-duty tires; office equipment such as copier feed rollers and winding rollers; parts used in furniture such as sofas and chair seats; rubber parts such as switch covers, stoppers, casters, and foot rubbers; building materials such as covered plywood and covered steel plates; and industrial components such as industrial belts and industrial rubber hoses. Among these, it is particularly suitable for tires or footwear, and more suitable for tread components or soles for footwear.

[0099] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these.

[0100] The components used in the examples and comparative examples are as follows:

[0101] • Rubber (I)-1: Styrene-butadiene rubber (E-SBR), product name "JSR 1502", manufactured by JSR Corporation, produced by emulsion polymerization, styrene unit content = 23.5% by mass • Rubber (I)-2: Natural rubber, from Indonesia, RSS No. 1 • Rubber (I)-3: Polybutadiene rubber (BR), product name "JSR BR01", manufactured by JSR Corporation, cis isomer content = 95% by mass, vinyl bond content = 2.5% by mass, weight-average molecular weight (Mw) = 550,000 • Rubber (I)-4: Polyisoprene rubber (IR), product name "Nipol® IR2200", manufactured by Nippon Zeon Co., Ltd.

[0102] ・Block copolymer (II)-1: Produced in Production Example 1 described below. ・Block copolymer (II)-2: Produced in Production Example 2 described below. ・Block copolymer (II')-1: Produced in Production Example 3 described below. ・Block copolymer (II')-2: Produced in Production Example 4 described below. ・Block copolymer (II')-3: Produced in Production Example 5 described below. ・Block copolymer (II')-4: Produced in Production Example 6 described below. ・Block copolymer (II')-5: Produced in Production Example 7 described below. Note that in the following explanation, block copolymer (II)-1 to 2 and block copolymer (II')-1 to 5 may be referred to as "block copolymer (II) or (II')".

[0103] • Tackifying resin: Hydrogenated petroleum resin, product name "ARKON P100", manufactured by Arakawa Chemical Industries, Ltd., softening point (ring-sphere method) 100±5℃ • Zinc oxide: product name "Zinc Oxide Type 1", manufactured by Sakai Chemical Industry Co., Ltd. • Stearic acid: product name "Lunaq S-20", manufactured by Kao Corporation • Silica: Wet-processed silica, product name "Nipsil VN3", manufactured by Tosoh Silica Co., Ltd., specific surface area 200m² by BET method ２ / g • Silane coupling agent: Bis[3-(triethoxysilyl)propyl]tetrasulfide, product name "Si69", manufactured by Evonik Japan • Crosslinking agent: Sulfur, product name "Fine Sulfur Powder", manufactured by Tsurumi Chemical Industries, Ltd., 200 mesh • Crosslinking accelerator (1): N-cyclohexyl-2-benzothiazole sulfenamide, product name "Noxellar CZ", manufactured by Ouchi Shinko Chemical Industry Co., Ltd. • Crosslinking accelerator (2): Tetramethylthiuram disulfide, product name "Noxellar TT", manufactured by Ouchi Shinko Chemical Industry Co., Ltd. • Crosslinking accelerator (3): Dibenzothiazole disulfide, product name "Noxellar DM", manufactured by Ouchi Shinko Chemical Industry Co., Ltd. • Crosslinking accelerator (4): Tetrabutylthiuram disulfide, product name "Noxellar TBT", manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0104] The details of the measurement method for block copolymer (II) or (II') obtained in each production example are as follows.

[0105] (1) Measurement of weight-average molecular weight (Mw) and molecular weight distribution The weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of block copolymer (II), block copolymer (II'), polymer block (A1), polymer block (A1'), and polymer block (A2) were determined by GPC (gel permeation chromatography) using standard polystyrene equivalent molecular weight. Block copolymer (II) and block copolymer (II') were the target of measurement, and the following measurement equipment and conditions were used: • Equipment: Tosoh Corporation GPC instrument "HLC-8320GPC" • Separation column: Tosoh Corporation column "TSKgelSuperHZ4000" • Eluent: Tetrahydrofuran • Eluent flow rate: 0.7 mL / min • Sample concentration: 5 mg / 10 mL • Column temperature: 40°C

[0106] (2) Method for measuring the hydrogenation rate Block copolymer (II) or (II') before hydrogenation and block copolymer (II) or (II') after hydrogenation are measured in CDClone. ３ Dissolve in it, １¹H-NMR measurements were performed [instrument: "AVANCE 400 Nano bay" (Bruker), measurement temperature: 30°C]. The hydrogenation rate of carbon-carbon double bonds in structural units derived from conjugated diene compounds in block copolymer (II) or (II') was calculated from the proton peaks of carbon-carbon double bonds appearing at 4.5–6.0 ppm in the obtained spectrum using the following formula: Hydrogenation rate (mol%) = {1 - (number of moles of carbon-carbon double bonds per mole of block copolymer (II) or (II') after hydrogenation) / (number of moles of carbon-carbon double bonds per mole of block copolymer (II) or (II') before hydrogenation)} × 100

[0107] (3) Method for measuring the amount of vinyl bonds in block copolymer (II) or (II') Block copolymer (II) or (II') before hydrogenation is divided into two parts: ３ Dissolve in it, １ ¹H-NMR measurements were performed [instrument: "AVANCE 400 Nano bay" (Bruker), measurement temperature: 30°C]. The amount of vinyl binding was calculated from the ratio of the peak areas of 1,2-binding units and 3,4-binding units to the total peak area of ​​structural units derived from the conjugated diene compound contained in the block copolymer (II) or (II'). In each production example, the amount of vinyl binding was calculated according to the following method. In production examples 1, 3, and 5, the amount of vinyl binding was calculated from the ratio of the peak areas of 3,4-binding units and 1,2-binding units in the isoprene-derived structural units to the total peak area of ​​the isoprene-derived structural units. In production examples 2 and 4, the amount of vinyl binding was calculated from the ratio of the peak area of ​​1,2-binding units in the butadiene-derived structural units to the total peak area of ​​the butadiene-derived structural units. In production examples 6 and 7, the amount of vinyl bonding was calculated from the ratio of the peak area of ​​1,2-bonding units in butadiene-derived structural units and the peak areas of 3,4-bonding units and 1,2-bonding units in isoprene-derived structural units to the total peak area of ​​butadiene-derived structural units and isoprene-derived structural units.

[0108] <Production of Block Copolymer (II)> [Production Example 1] (Block Copolymer (II)-1) In a nitrogen-purged and dried pressure vessel, 50.0 kg of cyclohexane was charged as a solvent and 0.0611 kg of sec-butyllithium (10.5% by mass cyclohexane solution) was charged as an anionic polymerization initiator. After raising the temperature to 50°C, 0.81 kg of styrene (1) was added and polymerization was carried out for 1 hour, followed by the addition of 10.87 kg of isoprene and polymerization was carried out for 2 hours, and then 0.81 kg of styrene (2) was added and polymerization was carried out for 1 hour to obtain a reaction solution containing polystyrene-polyisoprene-polystyrene triblock copolymer. To this reaction solution, 5% by mass of palladium carbon (palladium loading: 5% by mass) was added to the block copolymer as a hydrogenation catalyst, and the reaction was carried out for 10 hours under conditions of hydrogen pressure of 2 MPa and 150°C. After cooling and depressurization, palladium carbon was removed by filtration, the filtrate was concentrated, and further vacuum-dried to obtain hydrogenated polystyrene-polyisoprene-polystyrene triblock copolymer (SEPS). Similarly to SEPS, 50.0 kg of cyclohexane was charged as a solvent and 0.4200 kg of sec-butyllithium (10.5% by mass cyclohexane solution) (44.1 g of sec-butyllithium) as an anionic polymerization initiator into a nitrogen-purged and dried pressure vessel. After raising the temperature to 50°C, 2.83 kg of styrene(1) was added and polymerization was carried out for 1 hour, followed by the addition of 19.81 kg of isoprene and polymerization was carried out for 2 hours to obtain a reaction solution containing polystyrene-polyisoprene triblock copolymer. Hydrogenation was carried out to this reaction solution in the same manner as for SEPS to obtain hydrogenated polystyrene-polyisoprene triblock copolymer (SEP). The SEPS and SEP obtained above were melt-kneaded using a Coperion twin-screw extruder "ZSK26 MagaCopounder" (L / D = 56) at a screw speed of 300 rpm and a kneading temperature of 200°C to obtain block copolymer (II)-1, a mixture of SEPS and SEP. The physical properties of block copolymer (II)-1 were measured as described above. The results are shown in Table 1.

[0109] [Production Example 2] (Block Copolymer (II)-2) In a nitrogen-purged and dried pressure vessel, 50.0 kg of cyclohexane was charged as the solvent, 0.2362 kg of sec-butyllithium (10.5% by mass cyclohexane solution) as an anionic polymerization initiator, and 0.090 kg of tetrahydrofuran as a Lewis base. After raising the temperature to 50°C, 2.05 kg of styrene (1) was added and polymerization was carried out for 1 hour, followed by the addition of 13.75 kg of butadiene and polymerization was carried out for 2 hours to obtain a reaction solution containing polystyrene-polybutadiene diblock copolymer. Subsequently, 0.0128 kg of dichlorodimethylsilane (0.5 M toluene solution) was added to this reaction solution and stirred at 50°C for 1 hour to obtain a polystyrene-polybutadiene-polystyrene triblock copolymer in which a portion of the polystyrene-polybutadiene diblock copolymer was linked via a coupling agent. To the above reaction solution, palladium carbon (palladium loading: 5% by mass) was added at a concentration of 5% by mass relative to the block copolymer as a hydrogenation catalyst, and the reaction was carried out for 10 hours under conditions of hydrogen pressure of 2 MPa and 150°C. After cooling and release of pressure, the hydrogenation catalyst was removed by filtration, the filtrate was concentrated, and further vacuum-dried to obtain a block copolymer (block copolymer (II)-2) containing hydrogenated polystyrene-polybutadiene diblock copolymer (SEB) and hydrogenated polystyrene-polybutadiene-polystyrene triblock copolymer (SEBS). The above physical properties of block copolymer (II)-2 were measured. The results are shown in Table 1.

[0110] <Production of Block Copolymer (II')> [Production Example 3] (Block Copolymer (II')-1) In a nitrogen-purged and dried pressure vessel, 50.0 kg of cyclohexane was charged as a solvent and 0.0880 kg of sec-butyllithium (10.5% by mass cyclohexane solution) was charged as an anionic polymerization initiator. After raising the temperature to 50°C, 0.79 kg of styrene (1) was added and polymerization was carried out for 1 hour, then 7.24 kg of isoprene was added and polymerization was carried out for 2 hours, and then 0.79 kg of styrene (2) was added and polymerization was carried out for another hour to obtain a reaction solution containing polystyrene-polyisoprene-polystyrene triblock copolymer. To the above reaction solution, 5% by mass of palladium carbon (palladium loading: 5% by mass) was added to the block copolymer as a hydrogenation catalyst, and the reaction was carried out for 10 hours under conditions of hydrogen pressure of 2 MPa and 150°C. After cooling and pressure release, the hydrogenation catalyst was removed by filtration, the filtrate was concentrated, and then vacuum-dried to obtain hydrogenated polystyrene-polyisoprene-polystyrene triblock copolymer (SEPS) (block copolymer (II')-1). The above physical properties were measured for block copolymer (II')-1. The results are shown in Table 1.

[0111] [Production Example 4] (Block Copolymer (II')-2) In a nitrogen-purged and dried pressure vessel, 50.0 kg of cyclohexane was charged as the solvent, 0.1028 kg of sec-butyllithium (10.5% by mass cyclohexane solution) as an anionic polymerization initiator, and 0.073 kg of tetrahydrofuran as a Lewis base. After raising the temperature to 50°C, 1.32 kg of styrene (1) was added and polymerization was carried out for 1 hour. A mixture of 6.18 kg of butadiene was added and polymerization was carried out for 2 hours. A further 1.32 kg of styrene (2) was added and polymerization was carried out for 1 hour to obtain a reaction solution containing polystyrene-polybutadiene-polystyrene triblock copolymer. To the above reaction solution, 5% by mass of palladium (palladium loading amount: 5% by mass) was added to the block copolymer as a hydrogenation catalyst, and the reaction was carried out for 10 hours under conditions of hydrogen pressure of 2 MPa and 150°C. After cooling and pressure release, the hydrogenation catalyst was removed by filtration, the filtrate was concentrated, and further vacuum-dried to obtain hydrogenated polystyrene-polybutadiene-polystyrene triblock copolymer (SEBS) (block copolymer (II')-2). The above physical properties were measured for block copolymer (II')-2. The results are shown in Table 1.

[0112] [Production Example 5] (Block Copolymer (II')-3) In a nitrogen-purged and dried pressure vessel, 50.0 kg of cyclohexane was charged as a solvent and 0.0488 kg of sec-butyllithium (10.5% by mass cyclohexane solution) was charged as an anionic polymerization initiator. After raising the temperature to 50°C, 3.31 kg of styrene (1) was added and polymerization was carried out for 1 hour, and 5.52 kg of isoprene was added and polymerization was carried out for 2 hours to obtain a reaction solution containing polystyrene-polyisoprene block copolymer. To the above reaction solution, 5% by mass of palladium carbon (palladium loading: 5% by mass) was added to the block copolymer as a hydrogenation catalyst, and the reaction was carried out for 10 hours under conditions of hydrogen pressure of 2 MPa and 150°C. After cooling and release of pressure, the hydrogenation catalyst was removed by filtration, the filtrate was concentrated, and further vacuum-dried to obtain a hydrogenated polystyrene-polyisoprene block copolymer (SEP) (Block Copolymer (II')-3). The above physical properties of Block Copolymer (II')-3 were measured. The results are shown in Table 1.

[0113] [Production Example 6] (Block Copolymer (II')-4) In a nitrogen-purged and dried pressure vessel, 50.0 kg of cyclohexane was charged as a solvent and 0.0531 kg of sec-butyllithium (10.5% by mass cyclohexane solution) was charged as an anionic polymerization initiator. After raising the temperature to 50°C, 1.41 kg of styrene (1) was added and polymerization was carried out for 1 hour. A mixture of 2.66 kg of butadiene and 3.34 kg of isoprene was added and polymerization was carried out for 2 hours. Further polymerization was carried out by adding 1.41 kg of styrene (2) for 1 hour to obtain a reaction solution containing polystyrene-poly(butadiene / isoprene)-polystyrene triblock copolymer. To the above reaction solution, 5% by mass of palladium carbon (palladium loading: 5% by mass) was added to the block copolymer as a hydrogenation catalyst, and the reaction was carried out for 10 hours under conditions of hydrogen pressure of 2 MPa and 150°C. After cooling and pressure release, the hydrogenation catalyst was removed by filtration, the filtrate was concentrated, and then vacuum-dried to obtain hydrogenated polystyrene-poly(butadiene / isoprene)-polystyrene triblock copolymer (SEEPS) (block copolymer (II')-4). The above physical properties were measured for block copolymer (II')-4. The results are shown in Table 1.

[0114] [Production Example 7] (Block Copolymer (II')-5) In a nitrogen-purged and dried pressure vessel, 50.0 kg of cyclohexane was charged as the solvent, 0.0781 kg of sec-butyllithium (10.5% by mass cyclohexane solution) as an anionic polymerization initiator, and 0.205 kg of tetrahydrofuran as a Lewis base. After raising the temperature to 60°C, 0.47 kg of styrene (1) was added and polymerization was carried out for 1 hour. A mixture of 7.75 kg of butadiene and 6.15 kg of isoprene was added and polymerization was carried out for 2 hours. Further polymerization was carried out by adding 1.42 kg of styrene (2) for 1 hour to obtain a reaction solution containing polystyrene-poly(butadiene / isoprene)-polystyrene triblock copolymer. To the above reaction solution, 5% by mass of palladium carbon (palladium loading: 5% by mass) was added to the block copolymer as a hydrogenation catalyst, and the reaction was carried out for 10 hours under conditions of hydrogen pressure of 2 MPa and 150°C. After cooling and pressure release, the hydrogenation catalyst was removed by filtration, the filtrate was concentrated, and then vacuum-dried to obtain a hydrogenated polystyrene-poly(butadiene / isoprene)-polystyrene triblock copolymer (SEEPS) (block copolymer (II')-5). The above physical properties were measured for block copolymer (II')-5. The results are shown in Table 1.

[0115] *1: If block copolymer (II) or (II') is a triblock copolymer having a polymer block (A1) - polymer block (B1) - polymer block (A1') bonding configuration, it means monomers of polymer block (A1) and polymer block (A1'). If block copolymer (II) or (II') is a diblock copolymer having a polymer block (A2) - polymer block (B2) bonding configuration, it means monomer of polymer block (A2). *2: If block copolymer (II) or (II') is a triblock copolymer having a polymer block (A1) - polymer block (B1) - polymer block (A1') bonding configuration, it means monomer of polymer block (B1). If block copolymer (II) or (II') is a diblock copolymer having a polymer block (A2) - polymer block (B2) bonding configuration, it means monomer of polymer block (B2). *3: If block copolymer (II) or (II') is a triblock copolymer having a polymer block (A1) - polymer block (B1) - polymer block (A1') bonding configuration, it means the mass ratio of polymer block (A1) and polymer block (A1') to polymer block (B1) [[(A1) + (A1')] / (B1)]. If block copolymer (II) or (II') is a diblock copolymer having a polymer block (A2) - polymer block (B2) bonding configuration, it means the mass ratio of polymer block (A2) to polymer block (B2) [(A2) / (B2)]. *4: Means the mass ratio of triblock copolymer to diblock copolymer [triblock / diblock]. *5: St = polystyrene block, Ip = polyisoprene block, Bd = polybutadiene block. *6: Values ​​listed in the form X / Y mean that X is the value in the triblock copolymer and Y is the value in the diblock copolymer.*7: If block copolymer (II) or (II') is a triblock copolymer having a polymer block (A1) - polymer block (B1) - polymer block (A1') bonding configuration, it means the weight-average molecular weight (Mw) of polymer block (A1) and the weight-average molecular weight (Mw) of polymer block (A1'). If block copolymer (II) or (II') is a diblock copolymer having a polymer block (A2) - polymer block (B2) bonding configuration, it means the weight-average molecular weight (Mw) of polymer block (A2).

[0116] Examples 1-9, Comparative Examples 1-11 (1) Melt-mixing (Production of resin composition) According to the compositions (parts by mass) listed in Tables 3-5, each component except the crosslinking agent and crosslinking accelerator was placed in a mixing roll (14-inch roll, manufactured by Kansai Roll Co., Ltd.) under the conditions shown in Table 2 and melt-mixed (Steps 1 and 2). The melt-mixed material was then removed from the open roll (Step 3). Next, this melt-mixed material was placed in a mixing roll (Step 4), the crosslinking agent and crosslinking accelerator were added (Step 5), and the mixture was re-mixed and removed (Step 6) to obtain the resin composition. (2) Molding (Production of molded article) The resin composition obtained above was also press-molded (165°C, 10 MPa, 7-40 minutes) to crosslink and obtain a rubber sheet with more than 90% crosslinking. Rubber sheets with a thickness of 0.5 mm and a thickness of 1.0 mm were produced.

[0117]

[0118] <Measurement and Evaluation> The rubber sheets obtained in the above examples and comparative examples were used to evaluate their physical properties based on the evaluation method described below. The results are shown in Tables 3 to 5.

[0119] (Static friction coefficient) (1) Dry The static friction coefficient of the surface of the 0.5 mm thick rubber sheet obtained in the examples and comparative examples was measured in accordance with ASTM D-1894. A test piece measuring 110 mm in length, 63.5 mm in width, and 0.5 mm in thickness was cut from the above rubber sheet, wrapped around a cell (weighing 200 g, 63.5 mm x 63.5 mm), and fixed to the autograph head so that the test piece stand of the friction coefficient measuring device was horizontal. The material of the friction stand was aluminum, and the static friction coefficient was measured at a tensile speed of 150 mm / min. The larger the value of the static friction coefficient, the greater the frictional force, the less slippery it is, and the better the dry grip. (2) Wet The static friction coefficient was measured in the same manner as in (1) dry above, except that 1 cc of distilled water was dropped onto the friction stand.

[0120] (Abrasion Resistance) The amount of abrasion was measured by the DIN abrasion test in accordance with JIS K 6264-2:2005. A smaller value indicates better abrasion resistance.

[0121] (Hardness and Hardness Change Rate) From the 1.0 mm thick rubber sheets obtained in the examples and comparative examples, dumbbell-shaped test specimens of type 3 with a thickness of 1.0 mm were obtained using a punching die in accordance with JIS K 6251:2023. Six of the obtained test specimens were stacked to form a 6 mm thick sheet, which was used for hardness measurement. In accordance with JIS K 6253-3:2023, the hardness of the sheet at 23°C was measured using a type A durometer. Then, the sheet was placed in a constant temperature bath at -20°C, and the hardness of the sheet in the constant temperature bath was measured after 30 minutes to 1 hour. The hardness change rate was calculated based on the following formula: Hardness change rate (%) = Hardness at -20°C × 100 / Hardness at 23°C

[0122] (Tensile breaking strength and tensile breaking elongation) Using a 1.0 mm thick dumbbell-shaped No. 3 test specimen prepared in the same manner as the hardness measurement described above, the tensile breaking strength and tensile breaking elongation were measured in accordance with JIS K 6251:2023. The higher the values ​​for tensile breaking strength and tensile breaking elongation, the better the tensile properties.

[0123] *1: This refers to the index calculated by the formula [static friction coefficient of each example × 100 / static friction coefficient of comparative example 1]. *2: This refers to the index calculated by the formula [100 / (amount of wear of each example / amount of wear of comparative example 1)].

[0124] *1: This refers to the index calculated by the formula [static friction coefficient of each example × 100 / static friction coefficient of comparative example 11]. *2: This refers to the index calculated by the formula [100 / (amount of wear of each example / amount of wear of comparative example 11)].

[0125]

[0126] From the results in Tables 3 to 5, it can be seen that the molded articles formed from the resin compositions of Examples 1 to 9 of this embodiment have good wear resistance and achieve a high degree of balance between dry grip and wet grip.

Claims

1. A resin composition comprising rubber (I) and a block copolymer (II), wherein the block copolymer (II) comprises a block copolymer (II-1) and a block copolymer (II-2), the block copolymer (II-1) is a triblock copolymer having a polymer block (A1)-polymer block (B1)-polymer block (A1') bonding structure, the block copolymer (II-2) is a diblock copolymer having a polymer block (A2)-polymer block (B2) bonding structure, the polymer block (A1), the polymer block (A1'), and the polymer block (A2) are polymer blocks containing structural units derived from aromatic vinyl compounds, and the polymer block (B1) and the polymer block (B2) are polymer blocks containing structural units derived from conjugated diene compounds.

2. The resin composition according to claim 1, wherein the polymer block (B1) and the polymer block (B2) contain at least one structural unit derived from a conjugated diene compound selected from the group consisting of isoprene-derived structural units and butadiene-derived structural units.

3. The resin composition according to claim 1, wherein the structural units derived from the conjugated diene compound in the polymer block (B1) and the polymer block (B2) contain structural units derived from isoprene.

4. The resin composition according to any one of claims 1 to 3, wherein the mass ratio [(I) / (II)] of the rubber (I) to the block copolymer (II) is 45 / 55 or more and 99 / 1 or less.

5. The resin composition according to any one of claims 1 to 4, wherein the block copolymer (II) is a hydrogenated block copolymer.

6. The resin composition according to claim 5, wherein the hydrogenation rate of carbon-carbon double bonds in the structural units derived from the conjugated diene compound in the block copolymer (II) is 94 mol% or more and 100 mol% or less.

7. The resin composition according to any one of claims 1 to 6, wherein the weight-average molecular weight (Mw) of the block copolymer (II-1) is 50,000 or more and 600,000 or less.

8. The resin composition according to any one of claims 1 to 7, wherein the weight-average molecular weight (Mw) of the block copolymer (II-2) is 10,000 or more and 150,000 or less.

9. The resin composition according to any one of claims 1 to 8, wherein the content of vinyl bond units in the total 100 mol% of structural units derived from the conjugated diene compound contained in the block copolymer (II) is 0 mol% or more and 50.0 mol% or less.

10. The resin composition according to any one of claims 1 to 9, further comprising a crosslinking agent.

11. The resin composition according to claim 10, wherein the crosslinking agent contains sulfur or a sulfur-containing compound.

12. The resin composition according to any one of claims 1 to 11, further containing silica, wherein the silica content is 1 part by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the total of the rubber (I) and the block copolymer (II).

13. A resin composition according to any one of claims 1 to 12, wherein the hardness measured at 23°C using a Type A durometer in accordance with JIS K 6253-3:2023 is 50 or more and 80 or less.

14. A resin composition according to any one of claims 1 to 13, for use in tires.

15. A resin composition according to any one of claims 1 to 13, for use in footwear.

16. A molded article of the resin composition according to any one of claims 1 to 15.

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