Resin composition, molded article, and elastic member

Abstract

Provided is a resin composition comprising a block copolymer (X) that includes a polymer block (A) which has a structural unit derived from an aromatic vinyl compound and a polymer block (B) which has a structural unit derived from a conjugated diene compound and an oil (Y), wherein: the polymer block (B) includes a crystalline ethylene block (B1); the content of the oil (Y) in the resin composition is greater than 10 parts by mass but less than 230 parts by mass per 100 parts by mass of the block copolymer (X); and the crystallization peak temperature T1 of the resin composition in a temperature range of -5°C to +50°C in differential scanning calorimetry is 8.0-34.0°C. Also provided are: a molded article of the resin composition; and an elastic member comprising the molded article.

Description

Resin composition, molded body, and stretchable member

[0001] The present invention relates to a resin composition, a molded article, and an elastic material. Specifically, the present invention relates to a resin composition, a molded article such as a film, a sheet, a thread, and a nonwoven fabric, and an elastic material including the molded article.

[0002] Polyurethane elastic yarns are widely used as elastic materials for waist gathers and side leakage prevention gathers in disposable diapers, as well as in sportswear such as swimwear and spats. While polyurethane elastic yarns have good elasticity, they generally have too much tightness, which tends to reduce comfort for the user. Furthermore, polyurethane elastic yarns are difficult to recycle, and there are concerns about the generation of toxic gases caused by polyurethane elastic yarns. For these reasons, there is a demand for alternative materials to polyurethane elastic yarns. However, the reality is that no alternative material to polyurethane elastic yarns has yet been developed that has adequate tightness, can maintain stress for a long period of time, and is suitable for recycling.

[0003] Patent Document 1 describes a styrene-based elastomer composition intended to improve solvent resistance, and Patent Document 2 describes a polypropylene resin composition containing a hydrogenated block copolymer intended to achieve both flexibility and low-temperature impact resistance.

[0004] U.S. Patent No. 6,703,449 International Publication No. 2017 / 188190

[0005] Patent Document 1 discloses that by reducing the vinyl content of the polybutadiene block in a block copolymer having both an aromatic vinyl hydrocarbon block and a polybutadiene block, the block copolymer becomes harder after hydrogenation and exhibits improved solvent resistance. However, Patent Document 1 does not disclose that the resin composition has a crystallization peak temperature within a temperature range of −5°C to +50°C as measured by differential scanning calorimetry, nor does it disclose spinning or recycling. Patent Document 2 discloses a hydrogenated block copolymer (a-3) having a crystallization peak at 12.5°C and a hydrogenated block copolymer (a-12) having a crystallization peak at 21.0°C. However, Patent Document 2 does not disclose that these hydrogenated block copolymers can be combined with a predetermined amount of oil to produce a resin composition suitable for spinning.

[0006] The present invention has been devised to solve the above-mentioned problems, and aims to provide a resin composition that has good spinnability and can be spun, and that produces a molded body having high stretchability, high stress retention, and good unwinding properties; molded bodies thereof, such as films, sheets, yarns, and nonwoven fabrics; and elastic members that include the molded bodies.

[0007] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have conceived the following invention and found that it is possible to solve the above-mentioned problems. That is, the present invention encompasses the following inventions: [1] A resin composition comprising a block copolymer (X) including a polymer block (A) containing structural units derived from an aromatic vinyl compound and a polymer block (B) containing structural units derived from a conjugated diene compound, and an oil (Y), wherein the polymer block (B) contains a crystalline ethylene block (B1), the content of the oil (Y) in the resin composition is more than 10 parts by mass and less than 230 parts by mass per 100 parts by mass of the block copolymer (X), and the crystallization peak temperature T1 of the resin composition within a temperature range of −5° C. to +50° C. as measured by differential scanning calorimetry is 8.0° C. to 34.0° C. [2] The resin composition according to [1] above, wherein the crystallization enthalpy ΔH1 of the resin composition, determined from the exothermic peak area in a temperature range of −5° C. to +50° C. by differential scanning calorimetry, is 2.0 J / g or more and 11.0 J / g or less. [3] The resin composition according to [1] or [2] above, wherein the order-disorder transition temperature ODT of the resin composition, determined by dynamic viscoelasticity measurement, is 300° C. or less. [4] The resin composition according to any one of [1] to [3] above, wherein the ratio MA / MB of the mass MA of the polymer block (A) to the mass MB of the polymer block (B) is 16 / 84 to 40 / 60. [5] The resin composition according to any one of [1] to [4] above, wherein the weight-average molecular weight Mw of the block copolymer (X) is 250,000 or less. [6] The resin composition according to any one of [1] to [5] above, wherein the oil (Y) is at least one selected from the group consisting of vegetable oil, mineral oil, white oil, paraffin oil, and naphthenic oil. [7] The resin composition according to any one of [1] to [6] above, wherein the oil (Y) is at least one selected from the group consisting of vegetable oil and paraffin oil. [8] The resin composition according to any one of [1] to [7] above, wherein the oil (Y) is vegetable oil. [9] A molded article obtained by using the resin composition according to any one of [1] to [8] above.

[10] A film which is the molded article according to [9] above.

[11] A sheet which is the molded article according to the above item [9].

[12] A yarn which is the molded article according to the above item [9].

[13] A nonwoven fabric which is the molded article according to the above item [9].

[14] A stretchable member comprising the molded article according to the above item [9].

[0008] According to the present invention, there are provided a resin composition which has good spinnability and can be spun, and which produces a molded body having high elasticity, high stress retention, and good unwinding properties; molded bodies thereof such as films, sheets, yarns, and nonwoven fabrics; and elastic members comprising the molded bodies.

[0009] 1 is an explanatory diagram of a method for measuring the order-disorder transition temperature (ODT);

[0010] The present invention will be described below based on one or more embodiments. However, the embodiments shown below are merely examples for embodying the technical concept of the present invention, and the present invention is not limited to the following description. Furthermore, although preferred embodiments are shown in this specification, a combination of two or more of the individual preferred embodiments is also a preferred embodiment. For matters shown as numerical ranges, when there are several numerical ranges, the lower limit and upper limit can be selectively combined to form a preferred embodiment. Furthermore, when a numerical range is described as "XX to YY" in this specification, it means "XX or more and YY or less."

[0011] [Resin Composition] A resin composition according to one or more embodiments of the present invention is a resin composition comprising a block copolymer (X) including a polymer block (A) containing a structural unit derived from an aromatic vinyl compound and a polymer block (B) containing a structural unit derived from a conjugated diene compound, and an oil (Y), wherein the polymer block (B) contains a crystalline ethylene block (B1), the content of the oil (Y) in the resin composition is more than 10 parts by mass and less than 230 parts by mass per 100 parts by mass of the block copolymer (X), and the resin composition has a crystallization peak temperature T1 of 8.0°C or higher and 34.0°C or lower within a temperature range of −5°C or higher and +50°C or lower, as measured by differential scanning calorimetry.

[0012] The crystallization peak temperature T1 of the resin composition is measured in accordance with JIS K7121 (2012). Specifically, the crystallization peak temperature T1 is expressed as the peak-top temperature of an exothermic peak in a temperature range of -5°C to +50°C observed when a sample is heated from 25°C to 200°C at a heating rate of 10°C / min using a differential scanning calorimeter (DSC) and then cooled from 200°C to -100°C at a cooling rate of 10°C / min. The peak-top temperature of the exothermic peak refers to the peak-top temperature of an exothermic peak associated with crystallization having an area of ​​1 g / J or more. The crystallization peak temperature T1 is specifically measured by the method described in the Examples.

[0013] As a result of various investigations, the present inventors have found that when the polymer block (B) constituting the resin composition contains a crystalline ethylene block (B1) and the resin composition contains a specific amount of oil (Y), good stress and appropriate spinnability are ensured, resulting in spinning and unwinding. The detailed reasons why the resin composition is spinnable and unwindable are not limited to these, but one of the reasons is thought to be that the dense microstructure provided by the crystalline ethylene block (B1) ensures unwindability, and the appropriate amount of oil provides good flexibility.

[0014] The crystallization peak temperature T1 of the resin composition is preferably 8.5°C or higher, more preferably 9.0°C or higher, and even more preferably 9.5°C or higher, from the viewpoint of easily achieving both good spinnability and high stress retention. It is also preferably 33.5°C or lower, more preferably 33.0°C or lower, even more preferably 32.5°C or lower, still more preferably 30.0°C or lower, still more preferably 28.0°C or lower, and even more preferably 25.0°C or lower. In other words, the crystallization peak temperature T1 is preferably 8.5°C or higher and 33.5°C or lower, more preferably 9.0°C or higher and 33.0°C or lower, even more preferably 9.0°C or higher and 32.5°C or lower, still more preferably 9.0°C or higher and 30.0°C or lower, still more preferably 9.0°C or higher and 28.0°C or lower, and even more preferably 9.5°C or higher and 25.0°C or lower. The crystallization peak temperature T1 of the resin composition is set as described above, for example, by blending a block copolymer (X) having an appropriate crystallization peak temperature T2 with an appropriate amount of oil.

[0015] The crystallization enthalpy ΔH1 of the resin composition, determined from the exothermic peak area in a temperature range of -5 ° C. or more and +50 ° C. by differential scanning calorimetry, is preferably 2.0 J / g or more, more preferably 2.5 J / g or more, and even more preferably 2.9 J / g or more. Also, preferably 11.0 J / g or less, more preferably 10.5 J / g or less, more preferably 10.0 J / g or less, even more preferably 9.5 J / g or less, even more preferably 9.0 J / g or less, even more preferably 8.5 J / g or less, even more preferably 8.0 J / g or less, even more preferably 7.5 J / g or less, even more preferably 7.0 J / g or less, even more preferably 6.5 J / g or less, and even more preferably 6.2 J / g or less. In other words, the crystallization enthalpy ΔH1 is preferably 2.0 J / g or more and 11.0 J / g or less, more preferably 2.5 J / g or more and 10.5 J / g or less, even more preferably 2.5 J / g or more and 10.0 J / g or less, still more preferably 2.5 J / g or more and 9.5 J / g or less, even more preferably 2.5 J / g or more and 9.0 J / g or less, still more preferably 2.9 J / g or more and 8.5 J / g or less, still more preferably 2.9 J / g or more and 8.0 J / g or less, still more preferably 2.9 J / g or more and 7.5 J / g or less, still more preferably 2.9 J / g or more and 7.0 J / g or less, still more preferably 2.9 J / g or more and 6.5 J / g or less, and still more preferably 2.9 J / g or more and 6.2 J / g or less. By having the ΔH1 in the above numerical range, it becomes easier to achieve both high stress retention and good spinnability. The ΔH1 is measured in accordance with JIS K7122 (2012). Specifically, it is measured by the method described in the Examples. The ΔH1 of the resin composition is set as described above, for example, by mixing a block copolymer (X) having an appropriate crystallization enthalpy with an appropriate amount of oil.

[0016] The order-disorder transition temperature (ODT) of the resin composition, as determined by dynamic viscoelasticity measurement, is preferably 300°C or less, more preferably 299°C or less. The lower limit is not particularly limited, but may be 0°C or more, 50°C or more, or 100°C or more. In other words, the order-disorder transition temperature (ODT) is preferably 0°C or more and 300°C or less, 50°C or more and 300°C or less, or 100°C or more and 299°C or less. Having the ODT within the above ranges provides excellent moldability and allows molding at low temperatures, making it easier to suppress deterioration of the resin composition during molding. The ODT is measured in accordance with JIS K7244-10 (2005), and more specifically, is measured by the method described in the Examples. The ODT of the resin composition can be set as described above, for example, by mixing the block copolymer (X) with an appropriate amount of oil.

[0017] Hereinafter, each component for obtaining the resin composition and a molded article using the same will be described in detail.

[0018] <Block Copolymer (X)> The block copolymer (X) constituting the resin composition according to one or more embodiments of the present invention comprises a polymer block (A) containing structural units derived from an aromatic vinyl compound and a polymer block (B) containing structural units derived from a conjugated diene compound. The block copolymer (X) comprises at least one selected from the group consisting of an unhydrogenated block copolymer (X0), which is a block copolymer that has not been hydrogenated, and a hydrogenated block copolymer (X1), which is a block copolymer that has been hydrogenated. The block copolymer (X) may comprise only the hydrogenated block copolymer (X1), only the unhydrogenated block copolymer (X0), or both the hydrogenated block copolymer (X1) and the unhydrogenated block copolymer (X0). From the viewpoint of facilitating the production of a crystalline ethylene block, the block copolymer (X) preferably comprises only the hydrogenated block copolymer (X1) or both the hydrogenated block copolymer (X1) and the unhydrogenated block copolymer (X0). In the latter case, the content of the hydrogenated block copolymer (X1) in 100% by mass of the block copolymer (X) is preferably 55.0% by mass or more, more preferably 65.0% by mass or more, and even more preferably 75.0% by mass or more, from the viewpoint of facilitating the formation of a crystalline ethylene block. It may also be 100% by mass or less, or may be 99.9% by mass or less. The content of the hydrogenated block copolymer (X1) in 100% by mass of the block copolymer (X) is preferably 55.0% by mass or more and 99.9% by mass or less, more preferably 65.0% by mass or more and 99.9% by mass or less, and even more preferably 75.0% by mass or more and 99.9% by mass or less.

[0019] Hereinafter, each component constituting the block copolymer (X) will be described, but unless otherwise specified, these descriptions apply to both the unhydrogenated block copolymer (X0) and the hydrogenated block copolymer (X1).

[0020] (Polymer Block (A)) The polymer block (A) contains a structural unit derived from an aromatic vinyl compound (hereinafter, sometimes abbreviated as "aromatic vinyl compound unit"). From the viewpoint of mechanical properties, the content of the structural unit derived from the aromatic vinyl compound is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, still more preferably 90% by mass or more, particularly preferably 95% by mass or more, based on 100% by mass of the polymer block (A). It may also be 100% by mass or less, 95% by mass or less, or even 90% by mass or less. In other words, the content of the structural unit derived from the aromatic vinyl compound based on 100% by mass of the polymer block (A) 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 85% by mass or more and 100% by mass or less, still more preferably 90% by mass or more and 100% by mass or less, particularly preferably 95% by mass or more and 100% by mass or less.

[0021] Examples of the aromatic vinyl compound include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, β-methylstyrene, 2,6-dimethylstyrene, 2,4-dimethylstyrene, α-methyl-o-methylstyrene, α-methyl-m-methylstyrene, α-methyl-p-methylstyrene, β-methyl-o-methylstyrene, β-methyl-m-methylstyrene, β-methyl-p-methylstyrene, 2,4,6-trimethylstyrene, α-methyl-2,6-dimethylstyrene, α-methyl-2,4-dimethylstyrene, β-methyl-2,6-dimethylstyrene, β-methyl-2,4-dimethylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, 2,6-dichlorostyrene, 2,4-dichlorostyrene, and α-chloro-o-chlorostyrene. Examples of the aromatic vinyl compounds include styrene, α-chloro-m-chlorostyrene, α-chloro-p-chlorostyrene, β-chloro-o-chlorostyrene, β-chloro-m-chlorostyrene, β-chloro-p-chlorostyrene, 2,4,6-trichlorostyrene, α-chloro-2,6-dichlorostyrene, α-chloro-2,4-dichlorostyrene, β-chloro-2,6-dichlorostyrene, β-chloro-2,4-dichlorostyrene, o-t-butylstyrene, m-t-butylstyrene, p-t-butylstyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-chloromethylstyrene, m-chloromethylstyrene, p-chloromethylstyrene, o-bromomethylstyrene, m-bromomethylstyrene, p-bromomethylstyrene, styrene derivatives substituted with a silyl group, indene, and vinylnaphthalene. These aromatic vinyl compounds may be used alone or in combination of two or more. Among these, from the viewpoint of the balance between production costs and physical properties, the aromatic vinyl compound is preferably at least one selected from the group consisting of styrene, α-methylstyrene, p-methylstyrene, and mixtures thereof, and more preferably styrene.

[0022] However, as long as the purpose and effects of the present invention are not hindered, polymer block (A) may contain less than 30 mass% of structural units derived from monomers other than aromatic vinyl compounds (hereinafter, sometimes abbreviated as "other monomer units"). Examples of such other monomers include at least one selected from the group consisting of butadiene, isoprene, 2,3-dimethylbutadiene, 1,3-pentadiene, 1,3-hexadiene, isobutylene, methyl methacrylate, methyl vinyl ether, N-vinylcarbazole, β-pinene, 8,9-p-menthene, dipentene, methylenenorbornene, and 2-methylenetetrahydrofuran. When polymer block (A) contains such other monomer units, the bonding form is not particularly limited and may be either random or tapered. The content of the structural units derived from the other monomers in 100% by mass of polymer block (A) is preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, still more preferably 10% by mass or less, particularly preferably 5% by mass or less, and may be substantially 0% by mass. It may also be 5% by mass or more, or even 10% by mass or more. In other words, the content of the structural units derived from the other monomers in 100% by mass of polymer block (A) is preferably 0% by mass or more and 30% by mass or less, more preferably 0% by mass or more and 20% by mass or less, even more preferably 0% by mass or more and 15% by mass or less, still more preferably 0% by mass or more and 10% by mass or less, particularly preferably 0% by mass or more and 5% by mass or less.

[0023] The block copolymer (X) may have at least one polymer block (A). When the block copolymer (X) has two or more polymer blocks (A), the polymer blocks (A) may be the same or different. When the polymer blocks (A) have one type of structural unit, "different polymer blocks (A)" means that at least one of the types of monomer units constituting the polymer block (A), the weight-average molecular weight Mw of the polymer block (A), and the stereoregularity of the polymer block (A) is different. When the polymer block (A) has two or more types of structural units, at least one of the types of monomer units constituting the polymer block (A), the weight-average molecular weight Mw of the polymer block (A), the stereoregularity of the polymer block (A), the ratio of each monomer unit, and the copolymerization form (random, tapered, block) is different. From the viewpoint of easily ensuring rubber elasticity, the block copolymer (X) preferably has two polymer blocks (A).

[0024] The weight-average molecular weight Mw of the polymer block (A) is not particularly limited, but from the viewpoints of mechanical strength and moldability, the weight-average molecular weight Mw of at least one polymer block (A) among the polymer blocks (A) contained in the block copolymer (X) is preferably 2,000 or more, more preferably 3,000 or more, even more preferably 4,000 or more, still more preferably 5,500 or more, and even more preferably 8,000 or more, and is also preferably 60,000 or less, more preferably 55,000 or less, even more preferably 50,000 or less, still more preferably 40,000 or less, still more preferably 35,000 or less, and even more preferably 30,000 or less. From the viewpoint of fluidity and impact resistance, the weight average molecular weight Mw of at least one polymer block (A) is preferably 3,000 or more, more preferably 3,500 or more, even more preferably 4,000 or more, still more preferably 4,200 or more, still more preferably 4,300 or more, and still more preferably 4,500 or more, and is preferably 60,000 or less, more preferably 15,000 or less, still more preferably 10,000 or less, still more preferably 9,000 or less, still more preferably 8,000 or less, and still more preferably 7,000 or less. In other words, from the viewpoint of mechanical strength and moldability, the weight average molecular weight Mw of the at least one polymer block (A) is preferably 2,000 or more and 60,000 or less, more preferably 3,000 or more and 55,000 or less, even more preferably 4,000 or more and 50,000 or less, still more preferably 5,500 or more and 40,000 or less, still more preferably 8,000 or more and 35,000 or less, and still more preferably 8,000 or more and 30,000 or less. From the viewpoint of fluidity and impact resistance, the weight average molecular weight Mw of the at least one polymer block (A) is preferably 3,000 or more and 60,000 or less, more preferably 3,500 or more and 15,000 or less, even more preferably 4,000 or more and 10,000 or less, still more preferably 4,200 or more and 9,000 or less, still more preferably 4,300 or more and 8,000 or less, and still more preferably 4,500 or more and 7,000 or less.

[0025] All "weight average molecular weights" described in this specification and claims are weight average molecular weights calculated in terms of standard polystyrene as determined by gel permeation chromatography (GPC). Detailed measurement methods can be performed in accordance with the methods described in the Examples. In the case of a triblock copolymer having an A1-B-A2 structure, which will be described later, the total weight average molecular weight of the polymer blocks "A1" and "A2" is the weight average molecular weight of the triblock copolymer. １ The weight average molecular weight of the polymer block "A2" can be calculated from the total content of the polymer blocks "A1" and "A2" confirmed by H-NMR measurement. The weight average molecular weight of the polymer block "A1" can be calculated by GPC measurement. The weight average molecular weight of the polymer block "A2" can be determined by subtracting the weight average molecular weight of the polymer block "A1" from the total content of the polymer blocks "A1" and "A2".

[0026] The content of polymer block (A) in 100% by mass of block copolymer (X) (when multiple polymer blocks (A) are present, the total content thereof) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, from the viewpoint of easily ensuring good stretchability and stress retention. It is also preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. In other words, the content of polymer block (A) in 100% by mass of the block copolymer (X) is preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 40% by mass or less, and even more preferably 15% by mass or more and 30% by mass or less. The content of polymer block (A) in the block copolymer (X) is １ It is determined by H-NMR measurement.

[0027] (Polymer Block (B)) The polymer block (B) includes a polymer block (B) containing a structural unit derived from a conjugated diene compound (hereinafter, sometimes abbreviated as a "conjugated diene compound unit"). In the resin composition according to one or more embodiments of the present invention, the block copolymer (X) includes a crystalline ethylene block (B1) as the polymer block (B), and preferably includes the crystalline ethylene block (B1) and an amorphous polymer block (B2). Here, the amorphous polymer block (B2) is different from the crystalline ethylene block (B1). The crystalline ethylene block (B1) and the amorphous polymer block (B2) will be described in detail later.

[0028] The conjugated diene compound unit is a structural unit derived from a conjugated diene compound. Specific examples include structural units derived from at least one conjugated diene compound selected from the group consisting of butadiene, isoprene, and β-farnesene. The conjugated diene compound is preferably at least one conjugated diene compound selected from the group consisting of butadiene and isoprene, and more preferably butadiene.

[0029] The content of the crystalline ethylene block (B1) in 100% by mass of the polymer block (B) is preferably 2% by mass or more, more preferably 3% by mass or more, and even more preferably 4% by mass or more, from the viewpoint of good unwinding property. Furthermore, from the viewpoint of easily ensuring good stretchability and stress retention, it is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. In other words, the content of the crystalline ethylene block (B1) in 100% by mass of the polymer block (B) is preferably 2% by mass or more and 20% by mass or less, more preferably 3% by mass or more and 15% by mass or less, and even more preferably 4% by mass or more and 10% by mass or less.

[0030] The content of the structural units derived from the conjugated diene compound in 100% by mass of polymer block (B) (i.e., the total content of the crystalline ethylene block (B1) and the amorphous polymer block (B2)) is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably substantially 100% by mass, from the viewpoint of easily achieving the desired effects. There is no particular upper limit, and it may be 100% by mass or less, 99% by mass or less, 98% by mass or less, 95% by mass or less, or 90% by mass or less. The content of the structural units derived from the conjugated diene compound in 100% by mass of polymer block (B) is preferably 60% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, even more preferably 80% by mass or more and 100% by mass or less, and particularly preferably 90% by mass or more and 100% by mass or less.

[0031] Furthermore, as long as the object and effect of the present invention are not hindered, polymer block (B) may contain structural units derived from other monomers other than the structural units derived from the conjugated diene compound. In this case, the content of structural units derived from other monomers other than the structural units derived from the conjugated diene compound in 100% by mass of polymer block (B) is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, particularly preferably 10% by mass or less, and may even be 0% by mass. There is no particular restriction on the lower limit of the content of structural units derived from other monomers other than the structural units derived from the conjugated diene compound in 100% by mass of polymer block (B), but it may be 0% by mass or more, 1% by mass or more, 2% by mass or more, 5% by mass or more, or 10% by mass or more. In other words, the content of structural units derived from monomers other than the structural units derived from the conjugated diene compound is preferably 0% by mass or more and 40% by mass or less, more preferably 0% by mass or more and 30% by mass or less, even more preferably 0% by mass or more and 20% by mass or less, and particularly preferably 0% by mass or more and 10% by mass or less.

[0032] Examples of the other monomer include aromatic vinyl compounds such as styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-t-butylstyrene, 2,4-dimethylstyrene, vinylnaphthalene, and vinylanthracene, as well as at least one compound selected from the group consisting of methyl methacrylate, methyl vinyl ether, N-vinylcarbazole, β-pinene, 8,9-p-menthene, dipentene, methylenenorbornene, 2-methylenetetrahydrofuran, 1,3-cyclopentadiene, 1,3-cyclohexadiene, 1,3-cycloheptadiene, and 1,3-cyclooctadiene.

[0033] When the polymer block (B) contains structural units derived from a monomer other than the structural units derived from a conjugated diene compound, the bonding form thereof is not particularly limited and may be either random or tapered, but is preferably random.

[0034] The vinyl bond content of polymer block (B) is preferably 10 mol % or more and 60 mol % or less, and more preferably 20 mol % or more and 50 mol % or less. The vinyl bond content refers to the total mol % of structural units derived from a conjugated diene compound bonded via 1,2-bonds, 3,4-bonds (in the case of farnesene), and 3,13-bonds (in the case of farnesene) relative to 100 mol % of all structural units constituting polymer block (B) (i.e., structural units derived from a conjugated diene compound bonded via a bond other than 1,4-bonds (in the case of farnesene) and 1,13-bonds (in the case of farnesene)). In other words, when the conjugated diene compound is other than farnesene, the vinyl bond content of polymer block (B) refers to the total mol % of structural units derived from a conjugated diene compound bonded via 1,2-bonds and 3,4-bonds relative to 100 mol % of all structural units constituting polymer block (B). Furthermore, when the conjugated diene compound is other than farnesene, the vinyl bond content of polymer block (B) refers to the total mol % of structural units derived from the conjugated diene compound that are bonded by bonds other than 1,4-bonds, relative to 100 mol % of all structural units constituting polymer block (B). When the conjugated diene compound is farnesene, the vinyl bond content of polymer block (B) refers to the total mol % of structural units derived from farnesene that are bonded by 3,13-bonds, relative to 100 mol % of all structural units constituting polymer block (B). Furthermore, when the conjugated diene compound is farnesene, the vinyl bond content of polymer block (B) refers to the total mol % of structural units derived from farnesene that are bonded by bonds other than 1,13-bonds, relative to 100 mol % of all structural units constituting polymer block (B). The vinyl bond content is measured by the method described in the Examples.

[0035] (Crystalline Ethylene Block (B1)) The polymer block (B) contains a crystalline ethylene block (B1). In this specification, a polymer block being "crystalline" means that it has a crystallization peak temperature. The crystallization peak temperature is measured in accordance with JIS K7121 (2012). Specifically, it is expressed as the peak-top temperature of an exothermic peak in a temperature range of -5°C or more and +50°C or less, observed when a sample is heated from 25°C to 200°C at a heating rate of 10°C / min and then cooled to -100°C at a cooling rate of 10°C / min using a differential scanning calorimeter (DSC). The peak-top temperature of the exothermic peak refers to the peak-top temperature of an exothermic peak associated with crystallization having an area of ​​1 g / J or more. Therefore, the crystalline ethylene block (B1) means a block in which ethylene skeletons are linked and exhibiting the above-mentioned "crystalline" property.

[0036] As described above, the presence of the crystalline ethylene block (B1) in the polymer block (B) provides good stretchability to the molded article obtained from the resin composition, and also makes it easier to unwind the fiber after spinning.

[0037] From the viewpoint of the balance between stretchability and unwindability, the content of the crystalline ethylene block (B1) in 100% by mass of the block copolymer (X) is preferably 3.0% by mass or more, more preferably 3.2% by mass or more, and even more preferably 3.5% by mass or more. It is also preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. In other words, the content of the crystalline ethylene block (B1) is preferably 3.0% by mass or more and 20% by mass or less, more preferably 3.2% by mass or more and 15% by mass or less, and even more preferably 3.5% by mass or more and 10% by mass or less.

[0038] In order to allow the crystalline ethylene block (B1) to be present in the polymer block (B), for example, a conjugated diene compound such as butadiene is used, and the polymerization conditions of the conjugated diene compound are adjusted (for example, a method in which a vinylating agent is not used or the amount of the vinylating agent is reduced, or a method in which a vinylating agent is added in the presence of a conjugated diene and then the conjugated diene is added) to produce structural units derived from a conjugated diene compound with a small vinyl bond content, followed by hydrogenation. In this specification, known vinylating agents can be used. Examples of vinylating agents include ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, and 2,2-di(2-tetrahydrofuryl)propane (DTHFP); glycol ethers such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether; amines such as triethylamine, N,N,N',N'-tetramethylenediamine, N,N,N',N'-tetramethylethylenediamine (TMEDA), and N-methylmorpholine; and metal salts such as sodium or potassium salts of aliphatic alcohols, such as sodium t-butylate, sodium t-amylate, and sodium isopentylate, or dialkylsodium cyclohexanolate, and sodium or potassium salts of alicyclic alcohols, such as sodium mentholate. These vinylating agents can be used alone or in combination of two or more.

[0039] The vinyl bond content of the polymer block (B1) is preferably 0 mol % or more and 20 mol % or less, and more preferably 2 mol % or more and 15 mol % or less. The vinyl bond content refers to the total mol % of structural units derived from a conjugated diene compound bonded via a 1,2-bond, a 3,4-bond (in the case of farnesene), and a 3,13-bond (in the case of farnesene) relative to 100 mol % of all structural units constituting the polymer block (B1) (i.e., structural units derived from a conjugated diene compound bonded via a bond other than a 1,4-bond (in the case of farnesene) and a 1,13-bond (in the case of farnesene)). In other words, when the conjugated diene compound is other than farnesene, the vinyl bond content of the polymer block (B1) refers to the total mol % of structural units derived from a conjugated diene compound bonded via a 1,2-bond and a 3,4-bond relative to 100 mol % of all structural units constituting the polymer block (B1). Furthermore, when the conjugated diene compound is other than farnesene, the vinyl bond content of the polymer block (B1) refers to the total mol % of structural units derived from the conjugated diene compound that are bonded by bonds other than 1,4-bonds, relative to 100 mol % of all structural units constituting the polymer block (B1). When the conjugated diene compound is farnesene, the vinyl bond content of the polymer block (B1) refers to the total mol % of structural units derived from farnesene that are bonded by 3,13-bonds, relative to 100 mol % of all structural units constituting the polymer block (B1). Furthermore, when the conjugated diene compound is farnesene, the vinyl bond content of the polymer block (B1) refers to the total mol % of structural units derived from farnesene that are bonded by bonds other than 1,13-bonds, relative to 100 mol % of all structural units constituting the polymer block (B1). The vinyl bond content is measured by the method described in the Examples.

[0040] (Amorphous Polymer Block (B2)) In the polymer block (B), the polymer block other than the crystalline ethylene block (B1) is an amorphous polymer block (B2) containing a structural unit derived from a conjugated diene compound. Examples of such an amorphous polymer block (B2) include polymer blocks containing a structural unit derived from a conjugated diene compound such as butadiene, isoprene, or β-farnesene. The conjugated diene compound is preferably at least one selected from the group consisting of butadiene and isoprene, and more preferably butadiene. The vinyl bond content of the amorphous polymer block (B2) is preferably 10 mol % or more and 60 mol % or less, more preferably 20 mol % or more and 50 mol % or less. The vinyl bond content of polymer block (B2) means the total mol % of structural units derived from a conjugated diene compound bonded via 1,2-bonds, 3,4-bonds (in the case of other than farnesene), and 3,13-bonds (in the case of farnesene) (i.e., structural units derived from a conjugated diene compound bonded via a bond other than 1,4-bonds (in the case of other than farnesene) and 1,13-bonds (in the case of farnesene)) relative to 100 mol % of the total of all structural units constituting polymer block (B2). In other words, when the conjugated diene compound is other than farnesene, the vinyl bond content of polymer block (B2) means the total mol % of structural units derived from a conjugated diene compound bonded via 1,2-bonds and 3,4-bonds relative to 100 mol % of all structural units constituting polymer block (B2). When the conjugated diene compound is other than farnesene, the vinyl bond content of polymer block (B2) means the total mol % of structural units derived from the conjugated diene compound which are bonded by bonds other than 1,4-bonds, relative to 100 mol % of all structural units constituting polymer block (B2). When the conjugated diene compound is farnesene, the vinyl bond content of polymer block (B2) means the total mol % of structural units derived from farnesene which are bonded by 3,13-bonds, relative to 100 mol % of all structural units constituting polymer block (B2).When the conjugated diene compound is farnesene, the vinyl bond content of the polymer block (B2) means the total mol % of structural units derived from farnesene that are bonded by bonds other than 1,13-bonds, relative to 100 mol % of the total of all structural units constituting the polymer block (B2). The vinyl bond content is measured by the method described in the examples.

[0041] As used herein, a polymer block being "non-crystalline" means that it does not have a crystallization peak. The crystallization peak temperature is measured in accordance with JIS K7121 (2012). Specifically, it is expressed as the peak-top temperature of an exothermic peak in the temperature range of -5°C or higher and +50°C or lower, observed when a sample is heated from 25°C to 200°C at a heating rate of 10°C / min and then cooled to -100°C at a cooling rate of 10°C / min using a differential scanning calorimeter (DSC). If the area of ​​the exothermic peak is less than 1 g / J or if no exothermic peak is present, it is considered that the polymer block does not have a crystallization peak.

[0042] The content of the amorphous polymer block (B2) in 100% by mass of the block copolymer (X) is preferably 50% by mass or more, more preferably 55% by mass or more, and even more preferably 60% by mass or more, from the viewpoint of ensuring good stretchability and stress retention. It is also preferably 85% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less. In other words, the content of the amorphous polymer block (B2) is preferably 50% by mass or more and 85% by mass or less, more preferably 55% by mass or more and 80% by mass or less, and even more preferably 60% by mass or more and 75% by mass or less.

[0043] In order to incorporate the amorphous polymer block (B2) into the resin composition, for example, the polymerization conditions of the conjugated diene compound may be adjusted (for example, by adding an appropriate type and amount of a vinylating agent) to produce a structural unit derived from a conjugated diene compound having a relatively large amount of vinyl bonds.

[0044] The mixing ratio of the conjugated diene compound in the entire polymer block (B) [mass of crystalline ethylene block (B1) / mass of amorphous polymer block (B2)] is not particularly limited as long as the effects of the present invention are not impaired. From the viewpoint of the balance between stretchability and unwinding property, it is preferably 2 / 98 to 20 / 80, more preferably 3 / 97 to 15 / 85, and even more preferably 4 / 96 to 10 / 90.

[0045] The block copolymer (X) may have at least one polymer block (B). When the polymer block (B) has two or more types of structural units, the bonding form thereof may be random, tapered, completely alternating, partially block-like, block, or a combination of two or more of these. When the block copolymer (X) has two or more polymer blocks (B), the polymer blocks (B) may be the same or different. Note that, when the polymer block (B) has one type of structural unit, "different polymer blocks (B)" means that at least one of the types of monomer units constituting the polymer block (B), the weight-average molecular weight Mw of the polymer block (B), and the stereoregularity of the polymer block (B) is different. When the polymer block has two or more types of structural units, it means that at least one of the types of monomer units constituting the polymer block (B), the weight-average molecular weight Mw of the polymer block (B), the stereoregularity of the polymer block (B), the ratio of each monomer unit, and the copolymerization form (random, tapered, block) is different.

[0046] There are no particular limitations on the bond form of the conjugated diene compound as long as it does not impair the objects and effects of the present invention. For example, the bond forms of butadiene and isoprene can be 1,2-bonds and 1,4-bonds in the case of butadiene, and 1,2-bonds, 3,4-bonds, and 1,4-bonds in the case of isoprene. Only one type of these bond forms may be present, or two or more types may be present.

[0047] The content of polymer block (B) in 100% by mass of the block copolymer (X) (when multiple polymer blocks (B) are present, the total content of these polymer blocks) is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, from the viewpoint of the balance between flexibility and stress. It is also preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less. In other words, the content of polymer block (B) in 100% by mass of the block copolymer (X) is preferably 50% by mass or more and 95% by mass or less, more preferably 60% by mass or more and 90% by mass or less, and even more preferably 70% by mass or more and 85% by mass or less. The content of polymer block (B) in the block copolymer (X) is １ It is determined by H-NMR measurement.

[0048] (Mass Ratio of Polymer Block (A) to Polymer Block (B) in Block Copolymer (X)) From the viewpoint of the balance between flexibility and stress, the ratio MA / MB of the mass MA of the polymer block (A) to the mass MB of the polymer block (B) in the block copolymer (X) is preferably 16 / 84 or more and 40 / 60 or less, more preferably 18 / 82 or more and 36 / 64 or less, and even more preferably 20 / 80 or more and 32 / 68 or less.

[0049] (Bonding Mode Between Polymer Block (A) and Polymer Block (B)) The bonding mode between polymer block (A) and polymer block (B) in the block copolymer (X) may be any of an A-B structure, an A-B-A structure, or an A-B-A-B structure, where the polymer block (A) is represented by "A" and the polymer block (B) is represented by "B". From the viewpoint of a balance between stretchability, stress retention, and spinnability, an A-B-A structure in which the polymer block (A) is located at both ends is preferred.

[0050] More specific examples of the A-B-A type structure include those in which the block copolymer (X) is at least one selected from the group consisting of polystyrene-polyethylene-polybutylene-polystyrene (SEBS) block copolymers, polystyrene-polyethylene-polyethylene-polypropylene-polystyrene (SEEPS) block copolymers, polystyrene-polyfarnesene-polystyrene (SFS) block copolymers, and polystyrene-polyethylene-polypropylene-polystyrene (SEPS) block copolymers.

[0051] When a plurality of polymer blocks (A) are present, the plurality of polymer blocks (A) may be the same as or different from one another. When a plurality of polymer blocks (B) are present, the plurality of polymer blocks (B) may be the same as or different from one another. That is, in the case of the A-B-A type, when A1 and A2 are different polymer blocks (A), the structure may be A1-B-A2 or A1-B-A1. In addition, in the case of the A-B-A-B type, when B1 and B2 are different polymer blocks (B), the structure may be A-B1-A-B2 or A-B1-A-B1.

[0052] (Peak Top Molecular Weights of Polymer Block (A) and Polymer Block (B)) From the viewpoint of the balance between elasticity and spinnability, it is preferable that the peak top molecular weight of the polymer block (A) is 5,000 or more and 15,000 or less, and the peak top molecular weight of the polymer block (B) is 50,000 or more and 150,000 or less. The peak top molecular weights are measured by preparing a polymer of each polymer block alone and subjecting the polymer to gel permeation chromatography (GPC) measurement under the same conditions as those for measuring the weight average molecular weight Mw described below.

[0053] (Weight-Average Molecular Weight Mw of Block Copolymer (X)) From the viewpoint of spinnability, the weight-average molecular weight Mw of the block copolymer (X) is preferably 250,000 or less, more preferably 200,000 or less, and even more preferably 150,000 or less. From the viewpoint of stretchability, it is preferably 50,000 or more, more preferably 70,000 or more, and even more preferably 80,000 or more. In other words, the weight-average molecular weight Mw of the block copolymer (X) is preferably 50,000 or more and 250,000 or less, more preferably 70,000 or more and 200,000 or less, and even more preferably 80,000 or more and 150,000 or less. The weight-average molecular weight Mw is measured by the method described in the Examples.

[0054] (Vinyl Bond Content of Block Copolymer (X)) From the viewpoint of elasticity and stress retention, the vinyl bond content of the block copolymer (X) is preferably 5 mol% or more, more preferably 20 mol% or more, and even more preferably 35 mol% or more. It is also preferably 60 mol% or less, more preferably 50 mol% or less, and even more preferably 45 mol% or less. In other words, the vinyl bond content of the block copolymer (X) is preferably 5 mol% or more and 60 mol% or less, more preferably 20 mol% or more and 50 mol% or less, and even more preferably 35 mol% or more and 45 mol% or less. The vinyl bond content of the block copolymer (X) can be set within the above range, for example, by adjusting the type and amount of vinylating agent added during polymerization. The vinyl bond content refers to the total mol % of structural units derived from a conjugated diene compound bonded via 1,2-bonds, 3,4-bonds (in the case of other than farnesene), and 3,13-bonds (in the case of farnesene) (i.e., structural units derived from a conjugated diene compound bonded via a bond other than 1,4-bonds (in the case of other than farnesene) and 1,13-bonds (in the case of farnesene)) relative to 100 mol % of all structural units constituting the block copolymer (X). In other words, when the conjugated diene compound is other than farnesene, the vinyl bond content of the block copolymer (X) refers to the total mol % of structural units derived from a conjugated diene compound bonded via 1,2-bonds and 3,4-bonds relative to 100 mol % of all structural units constituting the block copolymer (X). Furthermore, when the conjugated diene compound is other than farnesene, the vinyl bond content of the block copolymer (X) refers to the total mol % of structural units derived from a conjugated diene compound bonded via a bond other than 1,4-bonds relative to 100 mol % of all structural units constituting the block copolymer (X). When the conjugated diene compound is farnesene, the vinyl bond content of the block copolymer (X) means the total mol % of structural units derived from farnesene bonded via 3,13-bonds, relative to 100 mol % in total of all structural units constituting the block copolymer (X).When the conjugated diene compound is farnesene, the vinyl bond content of the block copolymer (X) means the total mol % of structural units derived from farnesene that are bonded by bonds other than 1,13-bonds, relative to 100 mol % of the total of all structural units constituting the block copolymer (X). The vinyl bond content is measured by the method described in the Examples.

[0055] (Hydrogenation Ratio of Block Copolymer (X)) From the viewpoint of spinnability, the hydrogenation ratio of the block copolymer (X) is preferably 55.0 mol% or more, more preferably 65.0 mol% or more, and even more preferably 75.0 mol% or more. It is also preferably 100 mol% or less, and preferably 99.9 mol% or less. In other words, the hydrogenation ratio of the block copolymer (X) is preferably 55.0 mol% or more and 100 mol% or less, more preferably 65.0 mol% or more and 100 mol% or less, and even more preferably 75.0 mol% or more and 99.9 mol% or less. The hydrogenation ratio is measured by the method described in the Examples.

[0056] (Other Physical Properties of Block Copolymer (X)) From the viewpoint of easily setting T1 of the resin composition within an appropriate range, the crystallization peak temperature T2 of the block copolymer (X) is preferably 8.0°C or higher, more preferably 10.0°C or higher, even more preferably 12.0°C or higher, and even more preferably 14.0°C or higher. It is also preferably 35.0°C or lower, more preferably 34.5°C or lower, even more preferably 30.0°C or lower, and even more preferably 27.0°C or lower. In other words, the crystallization peak temperature T2 is preferably 8.0°C or higher and 35.0°C or lower, more preferably 10.0°C or higher and 34.5°C or lower, even more preferably 12.0°C or higher and 30.0°C or lower, and even more preferably 14.0°C or higher and 27.0°C or lower. The crystallization peak temperature T2 of the block copolymer (X) can be set as described above, for example, by adjusting the polymerization conditions of the conjugated diene compound. The crystallization peak temperature T2 of the block copolymer (X) can be measured in accordance with JIS K7121 (2012).

[0057] From the viewpoint of easily setting the ΔH1 of the resin composition within an appropriate range, the crystallization enthalpy ΔH2 of the block copolymer (X) is preferably 3.0 J / g or more, more preferably 4.0 J / g or more, even more preferably 5.0 J / g or more, and even more preferably 5.5 J / g or more. It is also preferably 12.0 J / g or less, more preferably 11.5 J / g or less, even more preferably 11.0 J / g or less, and even more preferably 10.5 J / g or less. In other words, the crystallization enthalpy ΔH2 is preferably 3.0 J / g or more and 12.0 J / g or less, more preferably 4.0 J / g or more and 11.5 J / g or less, even more preferably 5.0 J / g or more and 11.0 J / g or less, and even more preferably 5.5 J / g or more and 10.5 J / g or less. The crystallization enthalpy ΔH2 of the block copolymer (X) can be set as described above, for example, by adjusting the polymerization conditions of the conjugated diene compound. The crystallization enthalpy ΔH2 can be measured in accordance with JIS K7122 (2012).

[0058] <Oil (Y)> As described above, the oil (Y) constituting the resin composition according to one or more embodiments of the present invention is contained in the resin composition in an amount of more than 10 parts by mass and less than 230 parts by mass relative to 100 parts by mass of the block copolymer (X). From the viewpoint of facilitating spinning, the content of oil (Y) in the resin composition is preferably 12 parts by mass or more, more preferably 15 parts by mass or more, even more preferably 18 parts by mass or more, still more preferably 20 parts by mass or more, still more preferably 30 parts by mass or more, still more preferably 40 parts by mass or more, even more preferably 42 parts by mass or more, and still more preferably 45 parts by mass or more relative to 100 parts by mass of the block copolymer (X). From the viewpoint of a balance between flexibility and stress and of easily preventing bleed-out of oil (Y), the content of oil (Y) in the resin composition is preferably 220 parts by mass or less, more preferably 210 parts by mass or less, and even more preferably 205 parts by mass or less. In other words, the content of the oil (Y) is preferably 12 parts by mass or more and 220 parts by mass or less, more preferably 15 parts by mass or more and 220 parts by mass or less, even more preferably 18 parts by mass or more and 220 parts by mass or less, still more preferably 20 parts by mass or more and 210 parts by mass or less, still more preferably 30 parts by mass or more and 210 parts by mass or less, still more preferably 40 parts by mass or more and 210 parts by mass or less, still more preferably 42 parts by mass or more and 205 parts by mass or less, and still more preferably 45 parts by mass or more and 205 parts by mass or less.

[0059] From the viewpoint of facilitating recycling, the oil (Y) preferably contains at least one selected from the group consisting of vegetable oil, mineral oil, white oil, paraffin oil, and naphthenic oil. The oil (Y) preferably contains at least one selected from the group consisting of vegetable oil and paraffin oil. Furthermore, the oil (Y) may contain paraffin oil together with the vegetable oil. From the viewpoint of facilitating recycling, the oil (Y) more preferably contains paraffin oil. From the viewpoint of facilitating recycling and from the viewpoint of increasing the bio-based content, the oil (Y) more preferably contains vegetable oil. From the viewpoint of facilitating recycling, the oil (Y) is preferably at least one selected from the group consisting of vegetable oil, mineral oil, white oil, paraffin oil, and naphthenic oil. The oil (Y) is preferably at least one selected from the group consisting of vegetable oil and paraffin oil. Furthermore, the oil (Y) may be a combination of vegetable oil and paraffin oil. From the viewpoint of facilitating recycling, the oil (Y) is more preferably paraffin oil. From the viewpoints of facilitating recycling and increasing the bio-based content, the oil (Y) is preferably a vegetable oil. The vegetable oil is preferably at least one selected from the group consisting of palm oil, palm kernel oil, olive oil, soybean oil, rapeseed oil, sunflower oil, safflower oil, cottonseed oil, shea butter, coconut oil, cocoa butter, linseed oil, corn oil, rice bran oil, avocado oil, and oat oil. A combination thereof is also acceptable. The vegetable oil is more preferably at least one selected from the group consisting of palm oil and palm kernel oil. Furthermore, vegetable oils that have been hydrogenated during the production process (hydrogenated products) can also be used. Among the vegetable oils, at least one selected from the group consisting of vegetable oils containing a compound having a structure represented by the following formula (I), vegetable oils containing a compound having a structure represented by the following formula (II), and vegetable oils containing a compound having a structure represented by the following formula (I) and a compound having a structure represented by the following formula (II) is preferred.

[0060] However, in formula (I), n １ ~n ３ are each independently 1 or 3, and R １ ~R ６ are each independently a hydrogen atom or an unsubstituted hydrocarbon group, and R １ and R ２ The total number of carbon atoms in R is 14, ３ and R ４ The total number of carbon atoms in R is 14, ５ and R ６ The total number of carbon atoms in R is 14, １ ~R ６ may have a branched structure.

[0061] However, in formula (II), n ４ and n ５ are each independently 1 or 3, and R ７ ~R １０ are each independently a hydrogen atom or an unsubstituted hydrocarbon group, and R ７ and R ８ The total number of carbon atoms in R is 14, ９ and R １０ The total number of carbon atoms in R is 14, ７ ~R １０ may have a branched structure.

[0062] <Contents of Component (X) and Component (Y) in Resin Composition> In the resin composition according to one or more embodiments of the present invention, the total mass of the block copolymer (X) and the oil (Y) is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more, when the mass of the resin composition is 100% by mass, from the viewpoint of easily ensuring good biodegradability and hydrolysis resistance. There is no particular upper limit, and it may be 100% by mass or less, 95% by mass or less, or 90% by mass or less. In other words, the total mass of the block copolymer (X) and the oil (Y) in 100% by mass of the resin composition according to one or more embodiments of the present invention 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.

[0063] <Other Resins> The resin composition according to one or more embodiments of the present invention may contain a resin other than the block copolymer (X), for example, at least one selected from the group consisting of a styrene-based resin, a polyolefin resin, a polyolefin-based elastomer, and a tackifier resin. Examples of such styrene-based resins include poly-α-methylstyrene resin and polystyrene resin. Examples of polyolefin resins include polypropylene and polyethylene. Examples of tackifier resins include phenol-based resins and terpene-based resins.

[0064] From the viewpoint of effectively obtaining the effects of the present invention, the content of the resin other than the block copolymer (X) in the resin composition is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less, relative to 100 parts by mass of the total of the block copolymer (X) and the resin other than the block copolymer (X). There is no particular restriction on the lower limit, and it may be 0 parts by mass or 5 parts by mass or more. In other words, the content of the other resin is preferably 0 parts by mass or more and 50 parts by mass or less, more preferably 0 parts by mass or more and 40 parts by mass or less, and even more preferably 0 parts by mass or more and 30 parts by mass or less.

[0065] <Components Other Than Block Copolymer (X) and the Resin> The resin composition according to one or more embodiments of the present invention may contain components other than the block copolymer (X) and the resin. Examples of components other than the block copolymer (X) and the resin include inorganic fillers, softeners, heat-aging inhibitors, antioxidants, light stabilizers, antistatic agents, mold release agents, flame retardants, foaming agents, pigments, dyes, brighteners, UV absorbers, and lubricants. From the viewpoint of preventing the generation of harmful gases when the resin composition is burned, it is preferable that the components other than the block copolymer (X) and the resin are compounds that do not contain halogens, cyanides, or the like. These may be used alone, or two or more may be used in combination. The content of the components other than the block copolymer (X) and the resin may be determined appropriately depending on the desired physical properties of the resin composition. From the viewpoint of making it easier for the resin composition to exhibit the desired performance, the content is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, based on 100% by mass of the resin composition. In other words, the content of components other than the block copolymer (X) and the resin is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.5% by mass or more and 25% by mass or less, even more preferably 1.0% by mass or more and 20% by mass or less, and still more preferably 1.5% by mass or more and 15% by mass or less.

[0066] <Other Physical Properties of Resin Composition> (Biobased Degree) The biobased degree of the resin composition is measured in accordance with ASTM D6866-21. The biobased degree of the resin composition is preferably higher from the viewpoint of facilitating a reduction in the environmental impact. It is preferably 15% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more, based on 100% by mass of the resin composition. There is no particular upper limit and it may be 100% by mass. However, from the viewpoint of ease of production, it is preferably 95% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less. In other words, the biobased degree is preferably 15% by mass or more and 100% by mass or less, more preferably 20% by mass or more and 95% by mass or less, even more preferably 25% by mass or more and 85% by mass or less, and even more preferably 25% by mass or more and 80% by mass or less, based on 100% by mass of the resin composition. The biobased degree can be increased, for example, by using a plant-derived oil (Y) and increasing its content.

[0067] [Method for Producing Resin Composition] The method for producing the resin composition according to one or more embodiments of the present invention is not particularly limited. It is sufficient to uniformly mix the block copolymer (X), oil (Y), and, if necessary, additives. Examples of mixing methods include melt-kneading using a single-screw extruder, multi-screw extruder, Banbury mixer, heated roll, Brabender, various kneaders, etc., or melt-kneading by feeding each component through a separate inlet. Pre-blending may also be performed before melt-kneading. Examples of pre-blending methods include using a mixer such as a Henschel mixer, high-speed mixer, V-blender, ribbon blender, tumbler blender, or conical blender. The temperature during melt-kneading can be selected from a range of preferably 100°C to 300°C, taking into account the melting point and decomposition temperature of the resin composition. The melt-kneading time is, for example, 1 minute to 5 minutes.

[0068] [Molded Article] A molded article according to one or more embodiments of the present invention is a molded article made using any of the resin compositions described above. Examples of such molded articles include films, sheets, threads, nonwoven fabrics, and stretchable materials. The method for producing the films and sheets is not particularly limited, and various known molding methods can be used. Examples include injection molding, blow molding, press molding, extrusion molding, calendar molding, and molding using a 3D printer. The threads and nonwoven fabrics are preferably spun products of the resin composition, and more preferably melt-spun products.

[0069] When the molded article is a yarn, its fineness is preferably 50 dtex or more, more preferably 75 dtex or more, and even more preferably 100 dtex or more. It is also preferably 2,000 dtex or less, more preferably 1,500 dtex or less, and even more preferably 1,000 dtex or less. In other words, the fineness is preferably 50 dtex or more and 2,000 dtex or less, more preferably 75 dtex or more and 1,500 dtex or less, and even more preferably 100 dtex or more and 1,000 dtex or less. The number of filaments constituting the yarn is preferably 4 or more, more preferably 8 or more, and even more preferably 12 or more. It is also preferably 64 or less, more preferably 48 or less, and even more preferably 24 or less. In other words, the number of filaments constituting the yarn is preferably 4 or more and 64 or less, and more preferably 4 or more and 48 or less. The yarn may be either a monofilament or a bifilament. A monofilament is a yarn composed of one filament, and a bifilament is a yarn composed of multiple filaments. The filament may have a sheath-core structure, in which the core of the filament is a molded article of the resin composition according to one or more embodiments of the present invention, and a sheath containing polystyrene, polyethylene, polypropylene, or a combination of two or more of these is formed around the core. The sheath may also consist solely of polystyrene, polyethylene, polypropylene, or a combination of two or more of these. Furthermore, the filament may be a composite filament of a filament spun from the resin composition according to one or more embodiments of the present invention and a synthetic fiber.

[0070] When the molded article is a nonwoven fabric, the method for producing the nonwoven fabric is not particularly limited, and known methods can be used. Examples include resin bond, thermal bond, spunlace, spunbond, and meltblown methods. The produced nonwoven fabric can be used as a nanofiber nonwoven fabric, meltblown resin bond nonwoven fabric, thermal bond nonwoven fabric, spunlace nonwoven fabric, spunbond nonwoven fabric, meltblown nonwoven fabric, or nanofiber nonwoven fabric.

[0071] When the molded article is a sheet, its thickness may be 500 μm or more, 800 μm or more, or 1,000 μm or more. It may also be 4,000 μm or less, 3,000 μm or less, or 2,000 μm or less. In other words, the thickness of the sheet may be 500 μm or more and 4,000 μm or less, 800 μm or more and 3,000 μm or less, or 1,000 μm or more and 2,000 μm or less.

[0072] When the molded article is a film, its thickness may be 30 μm or more, 100 μm or more, or 150 μm or more. It may also be 500 μm or less, 400 μm or less, or 300 μm or less. In other words, the thickness of the film may preferably be 30 μm or more and 500 μm or less, 100 μm or more and 400 μm or less, or 150 μm or more and 300 μm or less.

[0073] [Stretchable Member] The stretchable member according to one or more embodiments of the present invention is a stretchable member comprising a molded article of any of the resin compositions described above. More specifically, the stretchable member is a composite of a molded article of the resin composition and other components, such as flexible materials such as yarn or paper. Furthermore, because the stretchable member exhibits high stretchability and high stress retention, when used in body-worn components such as disposable diapers and supporters, it provides a comfortable fit and comfortable fit to the user while improving wearability. More specific examples include disposable diapers and mask ear straps in which a molded article of the resin composition is used as an elastic material for waist gathers or side leakage prevention gathers. The molded article of the resin composition used in the stretchable member is preferably at least one selected from the group consisting of yarn, nonwoven fabric, sheet, and film. The resin composition is not a polymer having urethane bonds, such as polyurethane elastic yarn. Therefore, when the molded article is used as a composite by combining it with other materials (such as olefin compounds) and then recovered and reused, it has high compatibility with other materials. Therefore, the stretchable member can be easily recycled.

[0074] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0075] <Measurement and Evaluation of Physical Properties of Block Copolymers and Resin Compositions> The block copolymers X-1 to X-6 described below, and the resin compositions obtained in the examples and comparative examples described below, were measured for their physical properties according to the measurement methods below, and were also evaluated according to the evaluation methods below.

[0076] (Weight-average molecular weight Mw) The polystyrene-equivalent weight-average molecular weight Mw of each block copolymer was determined by gel permeation chromatography (GPC) measurement under the following conditions. <<GPC measurement device and measurement conditions>> Device: GPC device "HLC-8020" (manufactured by Tosoh Corporation) Separation column: Two "TSKgel G4000HX" columns manufactured by Tosoh Corporation were connected in series. Eluent: Tetrahydrofuran Eluent flow rate: 0.7 mL / min Sample concentration: 5 mg / 10 mL Column temperature: 40°C Detector: Differential refractive index (RI) detector Calibration curve: Prepared using standard polystyrene

[0077] (Vinyl Bond Amount) For the block copolymers of the production examples described later, the block copolymers before hydrogenation were each subjected to a HCl distillation. ３ Dissolve in １ H-NMR measurement was carried out [apparatus: "AVANCE 400 Nanobay" (manufactured by Bruker), measurement temperature: 30°C]. The vinyl bond content of the block copolymer, polymer block (B), and crystalline ethylene block (B1) was calculated from the ratio of the peak area corresponding to the 3,4-bond unit and 1,2-bond unit in the structural unit derived from isoprene and the 1,2-bond unit in the structural unit derived from butadiene to the total peak area observed at 4.0 to 6.0 ppm of the structural units derived from butadiene. The vinyl bond content of the polymer block (B2) was calculated using the following formula: Vinyl bond amount (polymer block (B2))=vinyl bond amount (polymer block (B))−vinyl bond amount (crystalline ethylene block (B1))×amount of chemical solution (butadiene (1)) / (amount of chemical solution (butadiene (1))+amount of chemical solution (butadiene (2))) Note that the above-mentioned amount of chemical solution refers to the value of the amount of chemical solution shown in Table 1.

[0078] (Hydrogenation rate) The block copolymer of the production example described later was ３ Dissolve in １H-NMR measurement [apparatus: "AVANCE 400 Nanobay" (manufactured by Bruker), measurement temperature: 30°C] was carried out, and the hydrogenation rate was calculated from the ratio of the peak area of ​​butadiene or isoprene derived from residual olefins to the peak area of ​​hydrogenated butadiene and hydrogenated isoprene.

[0079] (Crystallization Peak Temperature T and Crystallization Enthalpy ΔH) The crystallization peak temperature T2 of the block copolymer in the Production Examples described later and the crystallization peak temperature T1 of the resin compositions in the Examples and Comparative Examples described later were measured in accordance with JIS K7121 (2012). The crystallization enthalpy ΔH2 of the block copolymer in the Production Examples described later and the crystallization enthalpy ΔH1 of the resin compositions in the Examples and Comparative Examples described later were measured in accordance with JIS K7122 (2012). Specifically, using a DSC250 (manufactured by TA Instruments), the temperature was changed in the following order: heating step 1, cooling step, and heating step 2. T was determined from the peak temperature within the temperature range of -5°C to +50°C of the DSC curve obtained in the cooling step, and ΔH was determined from the peak area. The peak area was calculated by using a straight line passing through the two points of the peak temperature -30°C and the peak temperature +20°C on the DSC curve as the baseline. Heating step 1: Heat from +25°C to +200°C at a heating rate of 10°C / min. Cooling step: Cool from +200°C to -100°C at a cooling rate of 10°C / min. Heating step 2: Heat from -100°C to +200°C at a heating rate of 10°C / min.

[0080] (Order-Disorder Transition Temperature ODT) The resin compositions of the examples and comparative examples described below were compression molded at 200°C and 1.0 MPa for 3 minutes to obtain sheet-like molded articles (150 mm long, 150 mm wide, 1 mm thick). Cylindrical test pieces with a diameter of 25 mm and a height of 1 mm were punched out from the sheet, and the storage modulus G' was measured using the following equipment and conditions in accordance with JIS K7244-10 (2005). From the obtained data, a chart (α) was created with the vertical axis representing the logarithmic scale of the storage modulus G' and the horizontal axis representing temperature (°C). The temperature at which G' suddenly decreased in chart (α) was defined as the order-disorder transition temperature (ODT). The specific value of ODT was determined by finding the intersection point (point P in Figure 1) of the obtained chart in accordance with Figure 95 of JIS B0103-5113 (2015), and the temperature at point P was taken as the order-disorder transition temperature (ODT). ・Apparatus: ARES-G2 (manufactured by TA Instruments) ・Parallel plates: diameter 25 mm ・Vibration mode: torsional vibration mode ・Distortion amount: 0.1% ・Frequency: 1 Hz ・Measurement temperature: 50°C to 300°C ・Heating rate: 3°C / min

[0081] (Bio-based content) First, the bio-based content of the block copolymer and oil described below was measured in accordance with ASTM D6866-21. Specifically, the resin composition molded into pellets was burned, and the CO generated by the combustion was measured. ２ The CO ２ Using an accelerator mass spectrometer (AMS), １４ The concentration of CO in the atmosphere was measured. ２ in １４ The concentration of C and the measured １４ The biobased content of each block copolymer and each oil was calculated by comparing the concentration of C with that of the block copolymer (X) and the oil (Y). Then, for the resin compositions described below, the biobased content was calculated from the mass ratio of block copolymer (X) and oil (Y) and the biobased content of each component using the following formula (1): Biobased content = (X × i + Y × ii) / (X + Y) Formula (1) % by mass of block copolymer (X) % by mass of oil (Y) % by mass of block copolymer (i) % by mass of oil (ii)

[0082] (Stress Retention Rate) For the resin compositions of Examples 1 to 15, A1, and Comparative Examples 1 to 7, and C1 described below, a test sample was prepared by compression molding using a punching die at 200°C and 1.0 MPa for 3 minutes into a strip-shaped molded article measuring 75 mm long x 25 mm wide x 0.5 mm thick. For the resin compositions of Examples 16 to 17, A1, A2, and Comparative Examples C2 and C3 described below, a test sample was prepared by cutting the resin compositions into 50 mm lengths using scissors and bundling four of the yarns together. For Comparative Example 9, a test sample was prepared by cutting HYOSUNG polyurethane elastic yarn "CREORA Comfort 800Dtex" into 50 mm lengths using scissors. Furthermore, for the resin compositions of Examples 18-19 and Comparative Examples 10-15 described below, a ThermoFisher short-axis screw machine was used to process the resin compositions at a take-up speed of 2 m / min and a die temperature of 220°C to produce films of the thicknesses listed in Table 4, which were used as test samples. The test samples were then attached to a precision universal testing machine Autograph AGX-V (manufactured by Shimadzu Corporation) equipped with a 50 N load cell and a pneumatic grip installed in a thermostatic chamber maintained at 40°C, and the test specimens were stretched at 250 mm / min until they reached 50% elongation, and held for 120 minutes. The stress retention rate was calculated using the following formula (2): Stress retention rate = stress after 120 minutes of 50% elongation / stress after 50% elongation × 100... Formula (2) The stress retention rate of the resin composition is preferably high from the viewpoint of maintaining holding properties for a long period of time.

[0083] (Cycle Test) Test samples were prepared using the same procedure as for stress retention for the resin compositions of Examples 1 to 15, A1, and Comparative Examples 1 to 7, and C1 described below, the resin compositions of Examples 16 to 17, A1, A2, and Comparative Examples 9, C2, and C3 described below, and the resin compositions of Examples 18 to 19 and Comparative Examples 10 to 15 described below. The test samples were then attached to the pneumatic grip of an Instron 3345 (manufactured by Instron) equipped with a 100 N load cell, and the test samples were stretched at 250 mm / min until they reached 200% elongation, held at 200% elongation for 30 seconds, and then returned to 0% elongation at 250 mm / min. This procedure was repeated twice. Then, from the chart obtained by the measurement (an example is shown in Figure 2), the stress when the strain reached 200% during the second elongation ("2nd forward 200% stress") and the stress when the strain reached 50% during the second contraction ("2nd return 50% stress") were determined. The area (a-1) of the region surrounded by the points 2-1 (origin), 2-2 (position corresponding to the stress when the strain reached 200% during the second elongation), 2-3 (position corresponding to the stress at 200% strain when contraction begins after the second elongation), 2-4 (position where the stress reaches zero during the second contraction), and 2-1, and the area (a-2) connecting 2-1, 2-2, 2-5 (positions on the horizontal axis representing the strain where the strain is 200%), and 2-1, were used to calculate the 2nd hysteresis loss using the following formula (3): 2nd hysteresis loss=(a-1) / (a-2)×100 Equation (3) When the resin composition is subjected to a cycle test, the cycle characteristics obtained are such that the 2nd forward 200% stress is preferably low from the viewpoint of reducing discomfort caused by strong tightening, and the 2nd return 50% stress is preferably high to improve holding ability, and further, the 2nd hysteresis loss is preferably small.

[0084] (Spinability) For the resin compositions of Examples 1 to 15, A1 and Comparative Examples 1 to 7, and C1 described below, a capillary rheometer SEAST SR20 (manufactured by Instron) equipped with a φ1 mm capillary die and a 15 mm barrel was used. The piston was lowered at 5 mm / min, and the strand extruded from the capillary die was passed through a take-up roll located 30 cm vertically below the capillary die and fixed at a take-up speed of 3 m / min, and the spinnability was evaluated according to the following criteria: A: The strand did not break for 1 minute after passing through the take-up roll, and the strand thickness was stable. B: The strand did not break for 1 minute after passing through the take-up roll, and necking of the strand occurred, but at a level that was acceptable for practical use. C: The strand broke within 1 minute after passing through the take-up roll, and at a level that was not suitable for practical use.

[0085] (Spinnability, Fineness, and Unwinding Property) Spinnability The resin compositions of Examples 16-17, A2, and A3, and Comparative Examples 8, C2, and C3 described below were melted in a single-screw extruder and extruded from a spinning nozzle at 280°C. The yarn extruded from the spinneret was cooled to approximately room temperature using a cooling air device, and silicone oil was added as an oiling agent. Next, this yarn was wound around a paper tube via a roller at a winding speed of 2,000 m / min to obtain a yarn. The spinnability was then evaluated according to the following criteria: A: The spun yarn and filaments could be wound without breakage for 10 minutes, and were at a level that was acceptable for practical use. B: Some filaments broke within 10 minutes, but the spun yarn did not break, and were at a level that was acceptable for practical use. C: The spun yarn broke within 10 minutes, and was at a level that was not suitable for practical use. Fineness The mass of the obtained yarn was measured, and the fineness of the yarn was calculated based on the following formula (4): Fineness (dtex) = Mass (g) of 1 m of yarn × 10,000 ... formula (4) Unwinding property The yarn wound on a paper tube was stored at 30°C for 1 week, and then the end of the yarn was attached to the pneumatic grip of an Instron 3345 (manufactured by Instron) equipped with a 100 N load cell, and the paper tube around which the yarn was wound was placed directly below the pneumatic grip. The load (N) when unwinding at 500 mm / min was measured, and this was taken as unwinding property.

[0086] (Tensile Test) (Breaking Strength and Breaking Elongation of Yarn) Yarns of the resin compositions obtained in Examples 16 to 17, A2, and A3 and Comparative Examples 9, C2, and C3 described below were cut with scissors to a length of 50 mm to prepare test pieces. The test pieces were attached to a pneumatic grip provided on a precision universal testing machine Autograph AGX-V (manufactured by Shimadzu Corporation) equipped with a 50 N load cell, and then stretched at 500 mm / min until the test pieces broke, and the breaking strength and breaking elongation were measured. Higher values ​​for breaking strength and breaking elongation indicate better tensile properties.

[0087] [Production Example 1] Production of Block Copolymer X-1 A nitrogen-purged, dried pressure vessel was charged with 50 kg of cyclohexane (solvent) dried over molecular sieves A4, and 0.086 kg of a 10.5 mass% cyclohexane solution of sec-butyllithium as an anionic polymerization initiator (effective amount of sec-butyllithium added: 9.03 g). After heating the pressure vessel to 50 ° C, 0.901 kg of styrene (1) was added and polymerized for 60 minutes, followed by addition of 0.338 kg of butadiene (1) and polymerization for 2 hours. Next, 0.105 kg of tetrahydrofuran was added as a vinylating agent, and 6.422 kg of butadiene (2) was added and polymerization was continued for 2 hours. Thereafter, 1.352 kg of styrene (2) was added and polymerized for 60 minutes, and methanol was added to terminate the reaction, yielding a reaction solution containing a block copolymer having a polymer skeleton of polystyrene-polyethylene-polybutadiene-polystyrene (SEBS). A Ziegler hydrogenation catalyst formed from nickel octylate and trimethylaluminum was added to the reaction solution under a hydrogen atmosphere, and the mixture was reacted for 5 hours under conditions of a hydrogen pressure of 1 MPa and 80° C. After allowing the reaction solution to cool and release the pressure, the catalyst was removed by washing with water, and the mixture was dried in a vacuum to obtain a block copolymer X-1 having a polymer skeleton of polystyrene-polyethylene-polybutylene-polystyrene (SEBS) (more specifically, polystyrene-crystalline polyethylene-amorphous polyethylene-polybutylene-polystyrene).

[0088] Production Example 2 Production of Block Copolymer X-2 Block copolymer X-2, whose polymer skeleton is polystyrene-polyethylene-polybutylene-polystyrene (SEBS) (more specifically, polystyrene-crystalline polyethylene-amorphous polyethylene-polybutylene-polystyrene), was produced in the same manner as in Production Example 1, except that the raw materials and the amounts used were as shown in Table 1.

[0089] [Production Examples 3 and 4] Production of Block Copolymers X-3 and X-4 Block copolymers X-3 and X-4, whose polymer skeleton was polystyrene-polyethylene-polybutylene-polystyrene (SEBS), were produced in the same manner as in Production Example 1, except that the raw materials and the amounts thereof were as shown in Table 1 and the addition and polymerization of butadiene (1) were omitted.

[0090] Production Example 5 Production of Block Copolymer X-5 Block copolymer X-5, whose polymer skeleton was polystyrene-polyethylene-polypropylene-polystyrene (SEEPS), was produced in the same manner as in Production Example 1, except that the raw materials and the amounts thereof were as shown in Table 1, the addition of butadiene (1) and its polymerization were omitted, and a mixture of butadiene (2) and isoprene in the amounts shown in Table 1 was used instead of butadiene (2).

[0091] Production Example 6 Production of Block Copolymer X-6 Block copolymer X-6, whose polymer skeleton was polystyrene-polyethylene-polybutylene-polystyrene (SEBS) (more specifically, polystyrene-crystalline polyethylene-amorphous polyethylene-polybutylene-polystyrene), was produced in the same manner as in Production Example 1, except that the raw materials and the amounts used were as shown in Table 1.

[0092]

[0093] As shown in Table 1, block copolymers X-1, X-2, and X-6 exhibited an exothermic peak in the temperature range of −5° C. or higher and +50° C. in differential scanning calorimetry, and the crystallization peak temperature T2 and crystallization enthalpy ΔH2 could be measured. On the other hand, block copolymers X-3 to X-5 did not exhibit an exothermic peak in the temperature range of −5° C. or higher and +50° C. in differential scanning calorimetry, and the crystallization peak temperature T2 and crystallization enthalpy ΔH2 could not be measured.

[0094] [Examples 1 to 15 and Example A1] and [Comparative Examples 1 to 7 and Comparative Example C1] The block copolymers obtained in the above Production Examples and the following oils were prepared according to the formulations shown in Table 2. These materials were fed into a twin-screw extruder ("Zsk26Mc" manufactured by Coperion; number of cylinders: 14) at a cylinder temperature of 200°C and a screw rotation speed of 300 rpm, and the premixed composition was supplied to the hopper. The mixture was then melt-kneaded, extruded into strands, and cut to obtain resin compositions. Oil Y-1: PW-90 (paraffin oil, manufactured by Idemitsu Kosan Co., Ltd.) Oil Y-2: PW-380 (paraffin oil, manufactured by Idemitsu Kosan Co., Ltd.) Oil Y-3: VIVASPES10233 (vegetable oil containing a compound having a structure represented by the following formula (I) and / or formula (II), manufactured by H&R)

[0095] However, in formula (I), n １ ~n ３ are each independently 1 or 3, and R １ ~R ６ are each independently a hydrogen atom or an unsubstituted hydrocarbon group, and R １ and R ２ The total number of carbon atoms in R is 14, ３ and R ４ The total number of carbon atoms in R is 14, ５ and R ６ The total number of carbon atoms in R is 14, １ ~R ６ may have a branched structure.

[0096] However, in formula (II), n ４ and n ５are each independently 1 or 3, and R ７ ~R １０ are each independently a hydrogen atom or an unsubstituted hydrocarbon group, and R ７ and R ８ The total number of carbon atoms in R is 14, ９ and R １０ The total number of carbon atoms in R is 14, ７ ~R １０ may have a branched structure.

[0097] The measurement and evaluation results of the resin compositions of the examples and comparative examples are shown in Tables 2-1 to 2-3.

[0098]

[0099]

[0100]

[0101] As shown in Tables 2-1 and 2-2, the resin compositions of Examples 1 to 15 and Example A1 had crystallization peak temperatures T1 in the range of 8.0°C or higher and 34.0°C or lower, order-disorder transition temperatures ODT of 300°C or lower, and crystallization enthalpies ΔH1 in the range of 2.0 J / g or higher and 11.0 J / g or lower. Furthermore, the resin compositions of Examples 1 to 15 and Example A1 generally exhibited good results in the 2nd return 50% stress test in the cycle test. Furthermore, the resin compositions of Examples 1 to 15 and Example A1 generally exhibited high stress retention. Furthermore, the resin compositions of Examples 1 to 15 and Example A1 generally exhibited good spinnability. Furthermore, the resin compositions of Examples 12 and Example 13 had a higher biobased content than the other examples.

[0102] On the other hand, as shown in Table 2-3, the resin compositions of Comparative Examples 1 and 2, in which the oil content was outside the range of more than 10 parts by mass and less than 230 parts by mass, and the resin compositions of Comparative Examples 3 to 7 and Comparative Example C1, which did not have a crystallization peak temperature T1 within the temperature range of -5°C or higher and +50°C or lower as measured by differential scanning calorimetry, were inferior to the Examples in any of the cycle test evaluation, stress retention, and spinnability. Specifically, the resin compositions of Comparative Examples 1, 3, 4, 6, and Comparative Example C1 had significantly higher 2nd hysteresis loss than those of the Examples. Furthermore, the resin compositions of Comparative Examples 2 to 7 and Comparative Example C1 had lower stress retention than those of the Examples, and the resin compositions of Comparative Examples 4 and 5 in particular broke during the test. Furthermore, the resin compositions of Comparative Examples 1, 6, and 7 had poor spinnability.

[0103] [Examples 16-17] and [Comparative Example 8] According to the formulations shown in Table 3, resin compositions were melted in a single-screw extruder and prepared in the same manner as above, and threads were obtained using the procedures described in the "Spinnability" column above. In Examples 16 and 17, four of the resulting threads were bundled and evaluated.

[0104] Examples A2-A3 and Comparative Examples C2-C3: Yarn containing filaments with a core-sheath structure was produced according to the following procedures. (Procedure 1) The resin composition shown in Table 3 was used as the core component, and Resin Z-1 (S106 (Prime Polymer Co., Ltd., polypropylene, MFR = 20 g / 10 min)) was used as the sheath component. The core component and sheath component were melted in separate extruders in the mass ratios shown in Table 3, and composite fibers with a core-sheath cross section were extruded from a composite spinning nozzle. (Procedure 2) The yarn extruded from the spinneret was cooled to approximately room temperature using a cooling air device, and then silicone oil was applied as an oil agent. The oil-applied yarn was then wound onto a cardboard tube via a roller at a winding speed of 2,000 m / min.

[0105] [Comparative Example 9] Measurement and evaluation of the physical properties of polyurethane elastic yarn "CREORA Comfort 800Dtex" manufactured by HYOSUNG Co., Ltd. The results of measurement and evaluation of the physical properties of the yarns of Examples 16 to 17, Examples A2 to A3, and Comparative Examples 8, 9, and Comparative Examples C2 to C3 are shown in Table 3.

[0106]

[0107] As shown in Table 3, the resin compositions of Examples 16-17 and Examples A2-A3 exhibited good spinnability, allowing yarns of the specified fineness to be wound. Furthermore, the wound yarns stored at 30°C for one week could be smoothly unwound. On the other hand, the resin composition of Comparative Example 8 exhibited good spinnability, allowing yarns of the specified fineness to be wound, but after storage at 30°C for one week, the yarns fused together and could not be unwound. Furthermore, the resin composition of Example 16 exhibited tensile strength, breaking elongation, and stress retention equivalent to those of Comparative Example 9. Furthermore, the resin compositions of Examples 16 and 17 exhibited a lower 200% stress at the second going stretch than Comparative Example 9, and a 50% return stress at the second going stretch equal to or greater than that of Comparative Example 9.

[0108] The yarn containing the sheath-core filament of Example A2 had good melt spinnability and unwindability, and showed higher breaking strength and stress retention and smaller second hysteresis loss than the yarn containing the sheath-core filament of Comparative Example C2. The yarn containing the sheath-core filament of Example A3 had good melt spinnability and unwindability, and showed higher breaking strength and stress retention and smaller second hysteresis loss than the yarn containing the sheath-core filament of Comparative Example C3.

[0109] [Examples 18 and 19] and [Comparative Examples 10 to 15] According to the formulations shown in Table 4, the block copolymers obtained in the above Production Examples and the following oils were mixed using a twin-screw extruder (Coperion's "ZSK26Mc"; number of cylinders: 14) under kneading conditions of a cylinder temperature of 200°C and a screw rotation speed of 300 rpm, and the premixed composition was supplied to the hopper. The mixture was then melt-kneaded, extruded into strands, and cut to produce pellets of the resin composition. Next, a film of the resin composition was produced using a 20 mm single-screw machine (Thermo Fisher) set at a temperature of 220°C under the molding conditions shown in Table 3. Oil Y-4: VIVA-B-FIX 10227 (vegetable oil containing a compound having a structure represented by the above formula (I) and / or formula (II), manufactured by H&R)

[0110] The measurement and evaluation results of the films of Examples 18 and 19 and Comparative Examples 10 to 15 are shown in Table 4.

[0111]

[0112] Examples and Comparative Examples were compared, each containing the same amount of block copolymer and oil. As shown in Table 4, the film of Example 18 exhibited higher 50% stress at second return and higher stress retention than the films of Comparative Examples 10 to 12. The film of Example 19 also exhibited higher 50% stress at second return than the films of Comparative Examples 13 and 14, and also exhibited higher stress retention than the films of Comparative Examples 13 to 15. From these results, it can be seen that the films of Examples 18 and 19 have high stretchability.

[0113] The present invention provides a resin composition and molded articles thereof that are not too tight, maintain a moderate fit for a long time, are easily recyclable, and have good spinnability. The molded articles can be used as films, sheets, threads, nonwoven fabrics, and stretchable materials. Specifically, the resin composition is useful for applications such as fibers, such as woven fabrics and nonwoven fabrics; sportswear, such as swimsuits, spats, leotards, and cycling wear; underwear, such as briefs; protective or cold-weather gear, such as tights, arm covers, and neck covers; outerwear, such as slacks; seat coverings for automobile seats, sofas, and chairs; medical supplies, such as taping and supports; and hygiene products, such as disposable diapers, napkins, and masks. The resin composition is also useful for applications such as disposable diaper films and saddle cover films. Furthermore, the resin composition is useful for applications such as waterproof sheets and truck bed covers. This application is based on a Japanese patent application (Patent Application No. 2023-189987) filed on November 7, 2023, the entire contents of which are incorporated by reference.

[0114] 2-1: Origin 2-2: Position corresponding to the stress when the strain reaches 200% during the second extension 2-3: Position corresponding to the stress at 200% strain when contraction begins after the second extension 2-4: Position where the stress reaches zero during the second contraction 2-5: Position on the horizontal axis representing the strain where the strain is 200% 2-6: Position corresponding to the stress when the stress reaches 50% during the first contraction P: Intersection point

Claims

1. A resin composition comprising a block copolymer (X) including a polymer block (A) containing a structural unit derived from an aromatic vinyl compound and a polymer block (B) containing a structural unit derived from a conjugated diene compound, and an oil (Y), wherein the polymer block (B) contains a crystalline ethylene block (B1), the content of the oil (Y) in the resin composition is more than 10 parts by mass and less than 230 parts by mass per 100 parts by mass of the block copolymer (X), and the crystallization peak temperature T1 of the resin composition within a temperature range of -5°C or more and +50°C or less as measured by differential scanning calorimetry is 8.0°C or more and 34.0°C or less.

2. The resin composition according to claim 1, wherein the crystallization enthalpy ΔH1 of the resin composition, determined from the exothermic peak area in a temperature range of -5°C or more and +50°C or less by differential scanning calorimetry, is 2.0 J / g or more and 11.0 J / g or less.

3. The resin composition according to claim 1 or 2, wherein the order-disorder transition temperature ODT of the resin composition determined by dynamic viscoelasticity measurement is 300° C. or lower.

4. A resin composition according to claim 1 or 2, wherein the ratio MA / MB of the mass MA of the polymer block (A) to the mass MB of the polymer block (B) is 16 / 84 to 40 / 60.

5. The resin composition according to claim 1 or 2, wherein the weight average molecular weight Mw of the block copolymer (X) is 250,000 or less.

6. The resin composition according to claim 1 or 2, wherein the oil (Y) is at least one selected from the group consisting of vegetable oil, mineral oil, white oil, paraffin oil and naphthenic oil.

7. The resin composition according to claim 1 or 2, wherein the oil (Y) is at least one selected from the group consisting of vegetable oils and paraffin oils.

8. The resin composition according to claim 1 or 2, wherein the oil (Y) is a vegetable oil.

9. A molded article made using the resin composition according to claim 1 or 2.

10. A film which is the molded article according to claim 9.

11. A sheet which is the molded article according to claim 9.

12. A yarn which is the molded article according to claim 9.

13. A nonwoven fabric, which is the molded article according to claim 9.

14. An elastic member comprising the molded article according to claim 9.