Stretchable sheet and laminate

Abstract

Provided is a stretchable sheet that is formed from a resin composition containing: a copolymer (a) which is a block copolymer containing a polymer block A mainly composed of a vinyl aromatic compound and a polymer block B mainly composed of a conjugated diene compound, or is a hydrogenated product of the block copolymer; a hydrocarbon-based softening agent (b) in an amount of 50-200 parts by mass relative to 100 parts by mass of the copolymer (a); and a styrene-containing oligomer (c) in an amount of 5-20 parts by mass relative to 100 parts by mass of the copolymer (a). The stretchable sheet has a thickness of not more than 200 μm.

Description

Stretchable sheet and laminate

[0001] The present invention relates to a stretchable sheet and a laminate.

[0002] Clothing, daily necessities, sanitary products, and the like have parts that require elasticity, and various elastic materials including thermoplastic synthetic resins such as polyurethane resins, polystyrene resins, and vinyl resins, as well as natural resins, have been studied for use in these parts.

[0003] For example, Patent Document 1 discloses an elastic material having elasticity and flexibility, which contains a specific block copolymer and has adjusted physical properties such as residual strain. Patent Document 2 discloses an elastic member made of a thermoplastic polymer composition containing two specific block copolymers. Patent Document 3 discloses a porous sheet containing a specific block copolymer and a hydrocarbon-based softener.

[0004] Japanese Patent Application Publication No. 2002-363376 Japanese Patent Application Publication No. 2006-89546 Japanese Patent No. 6931363

[0005] According to the inventors' investigations, it has been found that with repeated use, conventionally used stretch sheets tend to lose their elasticity and become sagging. Furthermore, conventionally used stretch sheets made from polyurethane resins tend to be too tight, and when used in clothing, for example, this can adversely affect the comfort of the clothing.

[0006] Therefore, an object of the present invention is to provide a stretchable sheet that has a stretchable portion that exerts little tightness and does not sag even after repeated use.

[0007] The present inventors conducted extensive research into the materials and physical properties of stretchable sheets in order to solve the above problems, and as a result, discovered that the above problems could be solved by a stretchable sheet formed from a specific resin composition and having a specific thickness, thereby completing the present invention. That is, the present invention includes the following aspects.

[0008] [1] A stretchable sheet having a thickness of 200 μm or less, formed from a resin composition containing copolymer (a), which is a block copolymer containing a polymer block A mainly composed of a vinyl aromatic compound and a polymer block B mainly composed of a conjugated diene compound, or a hydrogenated copolymer thereof, and, relative to 100 parts by mass of copolymer (a), 50 to 200 parts by mass of hydrocarbon-based softener (b) and 5 to 20 parts by mass of styrene-containing oligomer (c). [2] The stretchable sheet according to [1], which has a tension of 1.5 N / 5 mm or less at 100% elongation. [3] The stretchable sheet according to [1] or [2], in which the combined amount of copolymer (a), hydrocarbon-based softener (b), and styrene-containing oligomer (c) is 85% by mass or more based on the total amount of the resin composition. [4] The stretchable sheet according to any one of [1] to [3], in which the resin composition has a flow initiation temperature of 200° C. or less. [5] The stretchable sheet according to any one of [1] to [4], which is heat-sealable at a temperature of 170°C or less. [6] The stretchable sheet according to any one of [1] to [5], in which the weight-average molecular weight of the copolymer (a) is 50,000 to 140,000. [7] The stretchable sheet according to any one of [1] to [6], in which the copolymer (a) contains structural units derived from a styrene-based monomer, and the amount of the structural units derived from the styrene-based monomer is 15% by mass or more based on the amount of all structural units of the copolymer (a). [8] The stretchable sheet according to any one of [1] to [7], in which the weight-average molecular weight of the styrene-containing oligomer (c) is 1,000 to 6,000. [9] The stretchable sheet according to any one of [1] to [8], in which the resin composition further contains 1 to 50 parts by mass of a polyolefin-based resin (d) per 100 parts by mass of the copolymer (a).

[10] The stretchable sheet according to [9], wherein the polyolefin resin (d) has a melt flow rate of 0.1 to 100 g / 10 min.

[11] The polyolefin resin (d) is a copolymer of ethylene and at least one C ３－ C １２The stretchable sheet according to [9] or

[10] , which is a copolymer with an α-olefin.

[12] The stretchable sheet according to any one of [1] to

[11] , wherein the amount of the acrylic block copolymer in the resin composition is 0 parts by mass or more and less than 20 parts by mass per 100 parts by mass of copolymer (a).

[13] The stretchable sheet according to any one of [1] to

[12] , wherein the length recovery rate of the stretchable sheet after 100% elongation is repeated three times at room temperature is 99.0% or more.

[14] The stretchable sheet according to any one of [1] to

[13] , wherein the length recovery rate of the stretchable sheet after being held in a 50% elongated state at 35°C for two hours is 87.0% or more.

[15] The stretchable sheet according to any one of [1] to

[14] , which is an stretchable tape.

[16] A laminate having at least a stretchable substrate layer (1) and a resin layer (2) adjacent to the stretchable substrate layer, the resin layer (2) being a layer formed from the stretchable sheet according to any one of [1] to

[15] .

[17] The laminate according to

[16] , in which the stretchable substrate layers (1) are adjacent to both sides of the resin layer (2).

[0009] According to the present invention, it is possible to provide a stretchable sheet that has a stretchable portion that exerts little tightness and does not sag even after repeated use.

[0010] Hereinafter, embodiments of the present invention will be described in detail. Note that the scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the spirit of the present invention.

[0011] The stretchable sheet of the present invention is formed from a resin composition containing: copolymer (a), which is a block copolymer containing polymer block A mainly composed of a vinyl aromatic compound and polymer block B mainly composed of a conjugated diene compound, or a hydrogenated copolymer thereof; and, relative to 100 parts by mass of copolymer (a), 50 to 200 parts by mass of a hydrocarbon-based softener (b) and 5 to 20 parts by mass of a styrene-containing oligomer (c), and the resin composition contains the following: copolymer (a) containing a vinyl aromatic compound; polymer block A mainly composed of a vinyl aromatic compound; and polymer block B mainly composed of a conjugated diene compound; copolymer (a), which is a block copolymer or a hydrogenated copolymer thereof;

[0012] [Resin Composition] (Copolymer (a)) The resin composition forming the stretch sheet of the present invention contains copolymer (a), which is a block copolymer or a hydrogenated product thereof, including polymer block A mainly composed of a vinyl aromatic compound and polymer block B mainly composed of a conjugated diene compound.

[0013] The polymer block A is a polymer block primarily composed of a vinyl aromatic compound. Examples of the vinyl aromatic compound include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-t-butylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 2,4,6-trimethylstyrene, 2-ethyl-4-benzylstyrene, 4-(phenylbutyl)styrene, 1-vinylnaphthalene, 2-vinylnaphthalene, vinylanthracene, N,N-diethyl-4-aminoethylstyrene, vinylpyridine, 4-methoxystyrene, monochlorostyrene, dichlorostyrene, and divinylbenzene. These vinyl aromatic compounds may be used alone or in combination of two or more. Among these, from the viewpoints of reducing stress at 100% elongation and improving stretchability, styrene, α-methylstyrene, and 4-methylstyrene are preferred, and styrene is more preferred.

[0014] As used herein, the phrase "mainly composed of a vinyl aromatic compound" means that the amount of structural units derived from a vinyl aromatic compound in polymer block A is greater than 50% by mass, based on the total amount of structural units in polymer block A. The amount of structural units derived from a vinyl aromatic compound is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more, particularly preferably 95% by mass or more, and especially preferably 100% by mass, based on the total amount of structural units in polymer block A.

[0015] Furthermore, from the viewpoint of reducing stress at 100% elongation and improving stretchability, the amount of structural units derived from a vinyl aromatic compound is preferably 5 to 75 mass %, more preferably 10 to 50 mass %, based on the amount of all structural units of copolymer (a).

[0016] Polymer block A may contain structural units derived from monomers other than vinyl aromatic compounds, such as monomers constituting polymer block B described below. In this case, the content of structural units derived from monomers other than vinyl aromatic compounds in polymer block A is less than 50% by mass, preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, still more preferably 10% by mass or less, and particularly preferably 5% by mass or less.

[0017] The polymer block B is a polymer block mainly composed of a conjugated diene compound. Examples of conjugated diene compounds include butadiene, isoprene, 2,3-dimethylbutadiene, 2-phenylbutadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 1,3-octadiene, 1,3-cyclohexadiene, 2-methyl-1,3-octadiene, 1,3,7-octatriene, myrcene, farnesene, and chloroprene. These conjugated diene compounds may be used alone or in combination of two or more. Among these, from the viewpoints of reducing stress at 100% elongation and improving stretchability, the conjugated diene compound is preferably at least one selected from the group consisting of butadiene, isoprene, and farnesene, and more preferably at least one selected from the group consisting of butadiene and isoprene.

[0018] As used herein, the phrase "mainly composed of a conjugated diene compound" means that the amount of structural units derived from a conjugated diene compound in polymer block B is more than 50% by mass, based on the amount of all structural units in polymer block B. The amount of structural units derived from a conjugated diene compound is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more, particularly preferably 95% by mass or more, and especially preferably 100% by mass, based on the amount of all structural units in polymer block B. When copolymer (a) is an at least partially hydrogenated polymer, the structural units derived from a conjugated diene compound also include structural units derived from a hydrogenated conjugated diene compound.

[0019] Furthermore, from the viewpoint of reducing stress at 100% elongation and improving stretchability, the amount of the structural units derived from the conjugated diene compound is preferably 25 to 95% by mass, more preferably 50 to 90% by mass, based on the amount of all structural units of the copolymer (a).

[0020] Polymer block B may contain structural units derived from monomers other than the conjugated diene compound, for example, other monomers such as the monomers constituting polymer block A. In this case, the content of structural units derived from monomers other than the conjugated diene compound in polymer block B is less than 50% by mass, preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, still more preferably 10% by mass or less, and particularly preferably 5% by mass or less.

[0021] The copolymer (a) is a block copolymer containing a polymer block A and a polymer block B or a hydrogenated product thereof, and is preferably a hydrogenated product of a block copolymer containing a polymer block A and a polymer block B. When the copolymer (a) is a hydrogenated product, preferably 50 mol % or more, more preferably 75 mol % or more, and even more preferably 95 mol % or more of the carbon-carbon double bonds derived from the conjugated diene compound of the polymer block B are hydrogenated.

[0022] Copolymer (a) may contain at least one polymer block A and at least one polymer block B. However, from the viewpoint of the heat resistance, mechanical properties, stretchability, etc. of the stretchable sheet, it preferably contains at least two or more polymer blocks A and one or more polymer blocks B. The bonding mode between polymer block A and polymer block B may be linear, branched, or any combination thereof. When polymer block A is represented by A and polymer block B is represented by B, a triblock structure represented by A-B-A or (A-B) ｎ , (A-B) ｎ Examples of suitable copolymers include multiblock copolymers represented by the formula A-B-A (where n is an integer of 2 or greater), and among these, those having a triblock structure represented by A-B-A are preferred from the viewpoints of the heat resistance, mechanical properties, stretchability, and handleability of the stretchable sheet. When copolymer (a) contains two or more polymer blocks A, the respective polymer blocks A may be the same or different. The same applies to the polymer blocks B.

[0023] The weight average molecular weight of copolymer (a) is preferably 50,000 or more, more preferably 52,000 or more, from the viewpoints of film-forming properties, heat resistance of the stretchable sheet, mechanical properties, stretchability, and ease of handling. From the viewpoint of stretchability, for example, return property after repeated stretching operations and / or after the stretched state has been maintained for a certain period of time, and from the viewpoint of reducing the thickness of the sheet, it is preferably 140,000 or less, more preferably 120,000 or less, and even more preferably 100,000 or less. The weight average molecular weight of copolymer (a) is preferably 50,000 to 140,000, more preferably 50,000 to 120,000, and even more preferably 52,000 to 100,000. The weight average molecular weight referred to in this specification refers to the weight average molecular weight in terms of standard polystyrene determined by gel permeation chromatography (GPC) measurement, for example, under the following conditions:

[0024] Measurement conditions: GPC: LC Solution (manufactured by SHIMADZU) Detector: differential refractometer RID-10A (manufactured by SHIMADZU) Column: two TSKgel G4000Hxl in series (manufactured by TOSOH) Guard column: TSKguardcolumnHxl-L (manufactured by TOSOH) Solvent: tetrahydrofuran Temperature: 40°C Flow rate: 1 ml / min Concentration: 2 mg / ml

[0025] In a preferred embodiment of the present invention, the copolymer (a) preferably contains a structural unit derived from a styrene-based monomer. In this embodiment, the content of the styrene-based monomer in the copolymer (a) 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 the total amount of the copolymer (a), from the viewpoint of improving elasticity. Furthermore, from the viewpoint of flexibility, it is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less. From the above viewpoints, the content of the styrene-based monomer in the copolymer (a) is preferably 15 to 50% by mass, more preferably 20 to 40% by mass, and even more preferably 25 to 35% by mass. The content of the structural unit derived from the styrene-based monomer in the copolymer (a) (also referred to as the styrene content) may be calculated from the monomer ratio when producing the copolymer (a), or １ It may also be calculated by H-NMR analysis or the like.

[0026] From the viewpoint of reducing stress at 100% elongation, the hardness of the copolymer (a) is preferably 20 A to 50 A, more preferably 25 A to 45 A, and even more preferably 30 A to 40 A. The hardness can be measured using a type A durometer based on JIS K 6253-1997 durometer hardness test.

[0027] The content of copolymer (a) contained in the resin composition is preferably 20% by mass or more, more preferably 25% by mass or more, and even more preferably 30% by mass or more, based on the total amount of the resin composition, from the viewpoint of improving stretchability, and is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 55% by mass or less, from the viewpoint of processability and handleability. From the above viewpoints, the content of copolymer (a) contained in the resin composition is preferably 20 to 70% by mass, more preferably 25 to 60% by mass, and even more preferably 30 to 55% by mass.

[0028] (Hydrocarbon-based softener (b)) The resin composition forming the stretch sheet of the present invention further contains a hydrocarbon-based softener (b) in addition to the copolymer (a). Examples of the hydrocarbon-based softener (b) include process oils such as paraffinic oil, naphthenic oil, and aromatic oil, and liquid paraffin, with process oils such as paraffinic oil and naphthenic oil being preferred. These may be used alone or in combination of two or more. The hydrocarbon-based softener (b) is preferably a non-aromatic hydrocarbon-based softener. Note that a non-aromatic hydrocarbon-based softener is a softener in which the proportion of the number of carbon atoms in the aromatic ring to the total number of carbon atoms in the molecule is preferably less than 35%, more preferably less than 30%, and even more preferably less than 25%.

[0029] The content of the hydrocarbon-based softener (b) is 50 to 200 parts by mass relative to 100 parts by mass of the copolymer (a) contained in the resin composition. If the content of the hydrocarbon-based softener (b) is less than 50 parts by mass, the elasticity of the resin composition may be too high, making it difficult to obtain stretchability. In addition, the resin composition may not have sufficient film-forming properties. On the other hand, if the content exceeds 200 parts by mass, the mechanical strength may not be obtained. From the viewpoint of reducing the stress at 100% elongation, the content of the hydrocarbon-based softener (b) is preferably 55 to 170 parts by mass, more preferably 60 to 150 parts by mass, and even more preferably 70 to 120 parts by mass relative to 100 parts by mass of the copolymer (a) contained in the resin composition.

[0030] The kinematic viscosity of the hydrocarbon-based softener (b) is preferably 10 to 500 mm when measured at 40°C in accordance with JIS K 2283:2000. ２ / s, and more preferably 50 to 450 mm ２ / s, and more preferably 100 to 400 mm ２ / s.

[0031] (Styrene-Containing Oligomer (c)) The resin composition forming the stretch sheet of the present invention further contains a styrene-containing oligomer (c) in addition to the copolymer (a) and the hydrocarbon-based softener (b). Herein, the styrene-containing oligomer is an oligomer having a structural unit derived from a styrene-based monomer, and does not fall under the category of the copolymer (a) described above. Examples of the styrene-containing oligomer (c) include polystyrene, poly-α-methylstyrene, poly-4-methylstyrene, styrene / α-methylstyrene copolymer, styrene / 4-methylstyrene copolymer, α-methylstyrene / 4-methylstyrene copolymer, and styrene / α-methylstyrene / 4-methylstyrene copolymer. The styrene-containing oligomer (c) may be used alone or in combination of two or more types.

[0032] As the styrene-containing oligomer (c), a commercially available product may be used.Commercially available products that can be used as the styrene-containing oligomer (c) include, for example, Picolastic A5 (polystyrene, softening point 5°C, Mw 350), Picolastic A-75 (polystyrene, softening point 74°C, Mw 1300), Picotex 75 (α-methylstyrene / 4-methylstyrene copolymer, softening point 75°C, Mw 1100), Picotex LC (α-methylstyrene / 4-methylstyrene copolymer, softening point 91°C, Mw 1350), Crystallex 3070 (styrene / α-methylstyrene copolymer, softening point 70°C, Mw 9 ... aromatic polymers manufactured by Eastman Corporation, such as Krystalex 3085 (styrene / α-methylstyrene copolymer, softening point 85°C, Mw 1150), Krystalex 3100 (styrene / α-methylstyrene copolymer, softening point 100°C, Mw 1500), Krystalex 5140 (styrene / α-methylstyrene copolymer, softening point 139°C, Mw 4900), Endex 155 (poly α-methylstyrene, softening point 153°C, Mw 6900), and Endex 160 (poly α-methylstyrene, softening point 158°C, Mw 9200); and Hymer ST-9 5 (polystyrene, softening point 95°C, Mw 4000; manufactured by Sanyo Chemical Industries), YS Resin SX-100 (polystyrene, softening point 100°C, Mw 2500; manufactured by Yasuhara Chemical Co., Ltd.), FMR-0150 (styrene / aromatic hydrocarbon copolymer, softening point 145°C, Mw 2040; manufactured by Mitsui Chemicals, Inc.), FTR-6100 (styrene / aliphatic hydrocarbon copolymer, softening point 95°C, Mw 1210; manufactured by Mitsui Chemicals, Inc.), FTR-6110 (styrene / aliphatic hydrocarbon copolymer, softening point 110°C, Mw 1570; manufactured by Mitsui Chemicals, Inc.), FTR-6125 (styrene / aliphatic hydrocarbon copolymer, softening point 110°C, Mw 1570; manufactured by Mitsui Chemicals, Inc.), Examples of such copolymers include FTR-7100 (styrene / α-methylstyrene / aliphatic hydrocarbon copolymer, softening point 100°C, Mw 1440; manufactured by Mitsui Chemicals), FTR-0100 (poly-α-methylstyrene, softening point 100°C, Mw 1960; manufactured by Mitsui Chemicals), FTR-2120 (styrene / α-methylstyrene copolymer, softening point 120°C, Mw 2630; manufactured by Mitsui Chemicals), and FTR-2140 (styrene / α-methylstyrene copolymer, softening point 137°C, Mw 3230; manufactured by Mitsui Chemicals).

[0033] The content of the styrene-containing oligomer (c) is 5 to 20 parts by mass relative to 100 parts by mass of the copolymer (a) contained in the resin composition. If the content of the styrene-containing oligomer (c) is less than 5 parts by mass, the styrene phase of the copolymer (a) is not reinforced, and it cannot withstand long-term elongation stress. On the other hand, if the content exceeds 20 parts by mass, the stretchable sheet may not have sufficient stretchability. From the viewpoint of preventing sagging, the content of the styrene-containing oligomer (c) is preferably 5 to 18 parts by mass, more preferably 6 to 17 parts by mass, and even more preferably 7 to 15 parts by mass relative to 100 parts by mass of the copolymer (a) contained in the resin composition.

[0034] The weight average molecular weight of the styrene-containing oligomer (c) is preferably 300 or more, more preferably 700 or more, even more preferably 1,000 or more, even more preferably 1,500 or more, and particularly preferably 2,000 or more, from the viewpoint of the styrene phase reinforcing effect of the copolymer (a). From the viewpoint of compatibility with the styrene phase of the copolymer (a), it is preferably 10,000 or less, more preferably 8,000 or less, even more preferably 6,000 or less, even more preferably 5,500 or less, and particularly preferably 5,000 or less. Therefore, the weight average molecular weight of the styrene-containing oligomer (c) is preferably 300 to 10,000, more preferably 700 to 8,000, even more preferably 1,000 to 6,000, even more preferably 1,500 to 5,500, and particularly preferably 2,000 to 5,000. The weight average molecular weight of the styrene-containing oligomer (c) can be determined by gel permeation chromatography in terms of standard polystyrene. The mechanism by which the styrene-containing oligomer reinforces the styrene phase of copolymer (a) is not clear, but it is thought that when a styrene-containing oligomer of a specific molecular weight is dissolved in the styrene phase of copolymer (a), the cohesive strength of the styrene phase increases, resulting in a reinforcing effect.

[0035] The content of the structural units derived from the styrene-based monomer in the styrene-containing oligomer (c) is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more, based on the total amount of the styrene-containing oligomer (c), from the viewpoint of compatibility with the styrene phase of the copolymer (a), and from the viewpoint of recovery after application of elongation stress for a long period of time, it is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. Therefore, from the above viewpoints, the content of the structural units derived from the styrene-based monomer in the styrene-containing oligomer (c) is preferably 40 to 90% by mass, more preferably 50 to 80% by mass, and even more preferably 60 to 70% by mass.

[0036] The softening point of the styrene-containing oligomer (c) is not particularly limited, but from the viewpoint of handling, it is preferably 110° C. or higher, more preferably 120° C. or higher, and even more preferably 130° C. or higher.

[0037] The resin composition forming the stretchable sheet of the present invention contains at least the above-mentioned copolymer (a), hydrocarbon-based softener (b), and styrene-containing oligomer (c), and the total amount of these components is, from the viewpoint of improving stretchability, preferably 85% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, based on the total amount of the resin composition, as long as it is 100% by mass or less.

[0038] (Other Components) The resin composition forming the stretchable sheet of the present invention may contain other components in addition to the copolymer (a), hydrocarbon-based softener (b), and styrene-containing oligomer (c) described above. Examples of other components include polyolefin-based resins (d), fillers (e), antioxidants (f), other resins, lubricants, light stabilizers, processing aids, colorants such as pigments and dyes, flame retardants, antistatic agents, matting agents, silicone oils, antiblocking agents, UV absorbers, release agents, foaming agents, antibacterial agents, antifungal agents, and fragrances.

[0039] The polyolefin resin (d) is not particularly limited as long as it is a resin obtained by polymerizing an olefin monomer, but from the viewpoint of the strength, moldability, chemical resistance, heat resistance, etc. of the stretchable sheet, propylene polymers, ethylene polymers, and mixtures thereof are preferred.

[0040] Examples of propylene-based polymers include homopolypropylene and copolymers of propylene and other α-olefins (e.g., random copolymers, block copolymers). The stereoregularity is not particularly limited, and the polymer may be isotactic polypropylene, syndiotactic polypropylene, atactic polypropylene, or the like. Among these, copolymers of other α-olefins and propylene (e.g., random copolymers and block copolymers) are preferred. Examples of other α-olefins include ethylene and α-olefins having 4 to 20 carbon atoms, such as ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 4-methyl-1-pentene. One type of other α-olefin may be used, or two or more types may be used in combination.

[0041] Examples of ethylene-based polymers include ethylene homopolymers such as low-density polyethylene (LDPE), medium-density polyethylene, and high-density polyethylene (HDPE); and copolymers of ethylene with other α-olefins (e.g., random copolymers and block copolymers). Examples of other α-olefins include α-olefins having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 4-methyl-1-pentene. One type of other α-olefin may be used, or two or more types may be used in combination. Specific examples include ethylene-α-olefin copolymers such as ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-heptene copolymer, ethylene-1-octene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-1-nonene copolymer, and ethylene-1-decene copolymer.

[0042] Furthermore, in order to enhance the compatibility between the copolymer (a) and the polyolefin resin (d), an active group-containing olefin resin may be used, which is obtained by copolymerizing (random copolymerization, graft copolymerization) the polyolefin resin (d) with a monomer having an active group such as a hydrosil group, a carbonyl group, an amide group, and / or an ester group.

[0043] From the viewpoint of film formability, the polyolefin resin (d) is preferably an ethylene polymer, more preferably a polymer of ethylene and at least one C ３－ C １２ and copolymers of ethylene and at least one C ３－ C ６ It is a copolymer with an α-olefin.

[0044] When the resin composition contains the polyolefin resin (d), the content thereof is preferably 1 to 50 parts by mass, more preferably 2 to 40 parts by mass, even more preferably 3 to 30 parts by mass, and even more preferably 4 to 20 parts by mass, relative to 100 parts by mass of the copolymer (a). When the content of the polyolefin resin (d) is within the above range, it is preferable because film-forming property and stretchability can be compatible.

[0045] The melt flow rate of the polyolefin resin (d) is preferably 0.1 to 100 g / 10 min, more preferably 1 to 80 g / 10 min, and even more preferably 5 to 50 g / 10 min, from the viewpoint of film formability when molding a stretchable sheet using the resin composition. The melt flow rate can be measured in accordance with JIS K7210-1:2014 (230°C, 2.16 kg load).

[0046] From the viewpoint of adhesiveness to fabrics, the melting point of the polyolefin resin (d) is preferably 100 to 150° C., more preferably 110 to 140° C., and even more preferably 120 to 130° C. The melting point can be measured by DSC.

[0047] Examples of the filler (e) include organic or inorganic fillers. Examples of the organic or inorganic filler include scaly inorganic fillers such as clay, diatomaceous earth, silica, talc, barium sulfate, calcium carbonate, magnesium carbonate, metal oxides, mica, graphite, and aluminum hydroxide. Furthermore, the organic or inorganic filler may include granular or powdered solid fillers such as various metal powders, wood chips, glass powder, ceramic powder, and granular or powdered polymers, as well as various other natural or artificial short or long fibers (e.g., straw, wool, glass fiber, metal fiber, and various other polymer fibers). From the viewpoint of handleability (reduced tackiness), the content of the filler (e) is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, and even more preferably 0 to 3% by mass, based on the total amount of the resin composition. In one embodiment of the present invention, the content of the filler (e) in the resin composition is preferably 10 mass% or less, more preferably 5 mass% or less, and even more preferably 1 mass% or less, relative to 100 mass parts of the copolymer (a). Even more preferably, the resin composition does not contain the filler (e).

[0048] Examples of the antioxidant (f) include hindered phenol-based, phosphorus-based, lactone-based, and hydroxyl-based antioxidants. Among these, hindered phenol-based antioxidants are preferred. When antioxidant (f) is contained, the content thereof is preferably within a range that does not cause coloration when the resin composition is melt-kneaded, and is preferably 0.1 to 5 parts by mass per 100 parts by mass of copolymer (a).

[0049] Examples of other resins include tackifying resins. Examples of tackifying resins include rosin-based resins, terpene-phenolic resins, terpene resins, aromatic hydrocarbons, modified terpene resins, aliphatic petroleum resins, alicyclic petroleum resins, aromatic petroleum resins, coumarone-indene resins, phenolic resins, and xylene resins. From the viewpoint of film-forming properties and processability when producing a stretchable sheet, the softening point of the tackifying resin is preferably 85 to 160°C, more preferably 100 to 150°C, and even more preferably 105 to 145°C. When the tackifying resin is contained, its content is preferably within a range that does not impair the mechanical properties of the resin composition, and is preferably 100 parts by mass or less, more preferably 70 parts by mass or less, even more preferably 30 parts by mass or less, and particularly preferably 10 parts by mass or less, per 100 parts by mass of copolymer (a).

[0050]

[0032] Another example of the resin is an acrylic block copolymer. The amount of the acrylic block copolymer in the resin composition of the present invention is preferably 0 parts by mass or more and less than 20 parts by mass, more preferably 0 parts by mass or more and 15 parts by mass or less, even more preferably 0 parts by mass or more and 10 parts by mass or less, and still more preferably 0 parts by mass or more and 5 parts by mass or less, relative to 100 parts by mass of the copolymer (a).

[0051] The flow initiation temperature of the resin composition forming the stretch sheet of the present invention is, from the viewpoint of film-forming properties and processability when producing the stretch sheet, preferably 200 ° C or less, more preferably 190 ° C or less, even more preferably 180 ° C or less, even more preferably 170 ° C or less, particularly preferably 160 ° C or less, especially more preferably 150 ° C or less, and extremely preferably 140 ° C or less; from the viewpoint of heat resistance, it is preferably 110 ° C or more, more preferably 120 ° C or more, and even more preferably 130 ° C or more. Therefore, the flow initiation temperature of the resin composition is preferably 110 to 200 ° C, more preferably 110 to 190 ° C, even more preferably 110 to 180 ° C, even more preferably 120 to 170 ° C, especially preferably 120 to 160 ° C, especially more preferably 130 to 150 ° C, and extremely preferably 130 to 140 ° C. The flow initiation temperature of the resin composition can be measured using a flow tester, and in detail, it can be measured by the method described in the examples.

[0052] The resin composition forming the stretchable sheet of the present invention preferably has a melt flow rate of 5 to 100 g / 10 min, more preferably 10 to 90 g / 10 min, and even more preferably 30 to 80 g / 10 min, from the viewpoints of film-forming properties and processability when producing the stretchable sheet. The melt flow rate can be measured in accordance with JIS K7210-1:2014 (190°C, 2.16 kg load).

[0053] The stretchable sheet of the present invention is a thin sheet having a thickness of 200 μm or less. From the viewpoint of producing such a thin sheet, the resin composition is required to have sufficiently high film-forming properties. From the viewpoint of improving film-forming properties, the extensibility of the resin composition is important, and the take-up speed at break measured by capillography under conditions of a piston extrusion speed of 10 mm / min, a die hole diameter of 1.0 mm, and a temperature of 170°C is preferably 35 m / min or more, more preferably 40 m / min or more, and even more preferably 50 m / min or more. Details of the method for measuring the take-up speed are as described in the examples.

[0054] The method for producing the resin composition forming the stretchable sheet of the present invention is not particularly limited, as long as it can uniformly mix the copolymer (a), hydrocarbon-based softener (b), styrene-containing oligomer (c), and, if necessary, other components such as polyolefin-based resin (d), filler (e), and antioxidant (f). Examples include a method in which these components are dissolved in a solvent, mixed, and optionally dried, or a method in which these components are melt-kneaded. From the viewpoint of enhancing the dispersibility of each component, a melt-kneading method is preferably used. Melt-kneading can be carried out using a melt-kneading device such as a single-screw extruder, twin-screw extruder, kneader, batch mixer, roller, or Banbury mixer. The resin composition forming the stretchable sheet of the present invention can be obtained by melt-kneading, preferably under conditions of 170 to 270°C and a screw rotation speed of 50 to 500 rpm.

[0055] [Stretchable Sheet] The stretchable sheet of the present invention is a sheet having stretchability and formed from the resin composition described above. The thickness of the stretchable sheet is 200 μm or less.

[0056] The thickness of the stretchable sheet of the present invention is 200 μm or less. Because the stretchable sheet of the present invention is a thin sheet of 200 μm or less, it is easy to use by laminating it to a substrate, and it can achieve both reduced tightening and stretchability. Furthermore, since the stretchable sheet is formed from the resin composition described above, it is possible to produce an extremely thin sheet of 200 μm or less. The thickness of the stretchable sheet can be measured, for example, using a thickness measuring device (thickness gauge). The thickness of the stretchable sheet of the present invention is not particularly limited as long as it is 200 μm or less and may be adjusted appropriately depending on the desired thickness. However, from the viewpoint of achieving both reduced stress at 100% elongation and fabric adhesion, it is preferably 50 to 200 μm, more preferably 60 to 170 μm, and even more preferably 70 to 150 μm.

[0057] The tension of the stretchable sheet at 100% elongation is preferably 1.5 N / 5 mm or less. When the tension at 100% elongation is 1.5 N / 5 mm or less, the constriction of the stretchable portion is small, and therefore when the stretchable sheet is used in, for example, clothing, it is thought that it is less likely to cause discomfort to the wearer of the clothing. From the viewpoint of achieving both reduced constriction and stretchability, the tension at 100% elongation of the stretchable sheet of the present invention is more preferably 0.3 N / 5 mm or more and 1.5 N / 5 mm or less, even more preferably 0.4 N / 5 mm or more and 1.2 N / 5 mm or less, and even more preferably 0.5 N / 5 mm or more and 1.0 N / 5 mm or less.

[0058] The tension of a stretchable sheet at 100% elongation is the tension value when a sample obtained by cutting the stretchable sheet to a width of 5 mm is used as a measurement sample, benchmark lines are drawn at a predetermined interval (for example, 20 mm) in the center of the measurement sample, and the sheet is pulled until the interval between the benchmark lines doubles (until 100% elongation), and can be measured, for example, by the method described in the Examples. Note that if the width of the stretchable sheet is less than 5 mm, the result of measurement using the sheet may be converted to a value corresponding to a 5 mm width, and this value may be used as the tension of the stretchable sheet at 100% elongation.

[0059] The stress at 100% elongation of the stretchable sheet is the tension at 100% elongation per cross-sectional area obtained by dividing the tension at 100% elongation measured as described above by the cross-sectional area of ​​the measurement sample. From the viewpoint of reducing tightening, the stress at 100% elongation of the stretchable sheet is preferably 0.33 to 0.76 MPa, more preferably 0.35 to 0.7 MPa, and even more preferably 0.40 to 0.65 MPa.

[0060] From the viewpoint of improving the stretchability and easily suppressing the occurrence of sagging during repeated use, the stretch sheet of the present invention preferably has a length recovery rate (hereinafter also referred to as "recovery rate A") of 99.0% or more after 100% elongation is repeated three times at room temperature. The recovery rate A is measured by using a sheet cut into a width of 5 mm and a length of 80 mm as a measurement sample, and measuring the distance between the gauge lines of the sheet before 100% elongation is repeated three times at room temperature. α The distance between the gauge lines of the stretchable sheet after the repetition is L βThe recovery rate is calculated by the following formula: Recovery rate A (%) = (1 - (L β -L α ) / L α )×100 The recovery rate A is more preferably 99.0% or more, even more preferably 99.5% or more, and even more preferably 99.9% or more.

[0061] From the viewpoint of improving the stretchability and easily suppressing the occurrence of sagging during repeated use, the stretch sheet of the present invention preferably has a length recovery rate of 84% or more after being held in a 50% elongated state at 35° C. for 2 hours (hereinafter also referred to as "recovery rate B"). The recovery rate B is measured by using a sheet cut into a width of 5 mm and a length of 80 mm as a measurement sample, and measuring the distance between the gauge lines of the sheet before being held in a 50% elongated state at 35° C. for 2 hours as L. ０ The distance between the gauge lines of the stretchable sheet after holding is L １ The recovery rate is calculated by the following formula: Recovery rate B (%) = (1 - (L １ -L ０ ) / L ０ )×100 The recovery rate B is more preferably 85% or more, even more preferably 87% or more, and even more preferably 89% or more.

[0062] The stretchable sheet of the present invention is typically a heat-sealable sheet. The stretchable sheet of the present invention may be used by heat-sealing to a substrate, or may not be heat-sealed. When heat-sealing to a substrate, the heat-sealing temperature is not particularly limited. However, from the viewpoint of ease of use in various applications, the stretchable sheet is preferably heat-sealable at a temperature of 215°C or less, more preferably 205°C or less, even more preferably 195°C or less, even more preferably 185°C or less, particularly preferably 175°C or less, especially preferably 170°C or less, extremely preferably 160°C or less, extremely preferably 150°C or less, and extremely preferably 140°C or less. Note that heat sealing is achieved by bonding the molten stretchable sheet to the substrate by close contact, so heat sealing is more likely to occur at high temperatures. On the other hand, from the viewpoint of reducing the impact of heat on the substrate and reducing the load on production equipment, a lower heat-sealing temperature is preferred. In this specification, the statement that a stretchable sheet is heat-sealable at or below a specific temperature does not exclude sheets that are heat-sealable at temperatures higher than that temperature, but means that the lower limit of the heat-sealable temperature range is at or below the specific temperature. Whether or not a stretchable sheet is heat-sealable at a specific temperature can be determined by placing the stretchable sheet on a test substrate and using a flat press (for example, a flat auto press HP-54N) at a specific temperature and a pressure of 4.0 N / cm. ２ If the sheet and the substrate do not peel off and can be bonded together when they are bonded together for 20 seconds, the sheet is considered to be heat-sealable at that temperature. It has been confirmed that stretchable sheets can be heat-sealed at temperatures that are 15°C higher than the flow initiation temperature of the resin composition that forms the stretchable sheet, and therefore the flow initiation temperature of the resin composition + 15°C may be used as the lower limit of the heat-sealable temperature.

[0063] The shape of the stretch sheet of the present invention is not particularly limited as long as it has a thickness of 200 μm or less, and may be, for example, a film, tape, or the like of a predetermined size. Furthermore, the stretch sheet may or may not be processed to be porous as necessary. In a preferred embodiment, the stretch sheet of the present invention is a non-porous sheet.

[0064] In a preferred embodiment of the present invention, the stretch sheet of the present invention is a stretch tape, for example, a stretch tape in which a long tape is wound around a core material. The size of the stretch tape may be appropriately set depending on the application for which the stretch tape is to be used and is not particularly limited, but for example, the width is preferably 1.0 to 5.0 cm, more preferably 1.5 to 4.5 cm, and even more preferably 2.0 to 4.0 cm. The length is preferably 20 to 50 m, more preferably 25 to 45 m, and even more preferably 30 to 40 m.

[0065] (Method for Producing Stretchable Sheet) The method for producing a stretchable sheet is not particularly limited as long as it is possible to produce a thin stretchable sheet having a thickness of 200 μm or less using the resin composition described above, and can be appropriately selected depending on the desired shape of the sheet. For example, the stretchable sheet of the present invention can be produced by molding the resin composition into a sheet having a thickness of 200 μm or less using a processing machine such as a heat press roll, a hot press, an injection molding machine, an insert injection machine, a sheet molding machine, a coextrusion sheet molding machine, an extrusion molding machine, or a calendar roll molding machine. To obtain a multilayer sheet, a coextrusion sheet molding machine, an extrusion lamination molding machine, a wet laminator, or the like may also be used. A method may also be used in which the resin composition is dissolved in a solvent such as toluene, and then the solution is applied and dried on a heated cast roll or a release film. Alternatively, a sheet having a thickness of more than 200 μm may be produced by any of the above methods, and then the thickness may be adjusted to 200 μm or less by performing additional processes such as a heat press process or a stretching process to produce the stretchable sheet of the present invention.

[0066] The stretchable sheet of the present invention can be used as a stretchable member as it is, or can be used in a state where it is laminated with at least one substrate. For example, in clothing applications, the stretchable sheet of the present invention can be used as a tape material used in stretchable parts or tightening parts at the ends, as a reinforcing material in parts where prevention of sagging of fabric is required, or as a seam tape in parts where waterproofing is required.

[0067] [Laminate] The present invention also provides a laminate in which the stretchable sheet of the present invention is laminated with, for example, at least one substrate. For example, a stretchable substrate and the stretchable sheet of the present invention may be laminated, and if necessary, the substrate and the stretchable sheet may be heat-sealed and / or sewn together to obtain a laminate in which a substrate layer and a resin layer formed from the stretchable sheet of the present invention are laminated. The present invention also provides a laminate having at least a stretchable substrate layer (1) and a resin layer (2) adjacent to the stretchable substrate layer, the resin layer (2) being a layer formed from the stretchable sheet of the present invention.

[0068] The stretchable substrate layer (1) is a layer of a substrate having stretchability, and examples of the substrate include knitted or woven fabrics, nonwoven fabrics, synthetic resin films, etc. The laminate of the present invention is preferably a stretchable laminate.

[0069] The method for producing the laminate of the present invention is not particularly limited, but examples include a method in which an elastic substrate is superimposed on one or both sides of the stretchable sheet of the present invention, and heat is applied while applying pressure as necessary to thermally fuse the stretchable substrate and the stretchable sheet. Alternatively, the laminate of the present invention may be produced by superimposing an elastic substrate on one or both sides of the stretchable sheet of the present invention and sewing them together.

[0070] The above-mentioned stretchable sheets and laminates can be used in various applications that require stretchable components, such as clothing, health products, medical products, sports equipment (especially sportswear), and underwear.

[0071] The present invention will be described below with reference to examples, but the present invention is not limited to these examples. First, the methods for measuring the physical properties in the examples and comparative examples are shown below.

[0072] [Weight-average molecular weight] The weight-average molecular weight was measured by gel permeation chromatography (GPC) under the following conditions: Measurement conditions: GPC: LC Solution (manufactured by Shimadzu Corporation) Detector: differential refractometer RID-10A (manufactured by Shimadzu Corporation) Column: two TSKgel G4000Hxl columns in series (manufactured by Tosoh Corporation) Guard column: TSKguard column Hxl-L (manufactured by Tosoh Corporation) Solvent: tetrahydrofuran Temperature: 40°C Flow rate: 1 ml / min Concentration: 2 mg / ml

[0073] [Melt flow rate (MFR)] The MFR of the resin composition was measured in accordance with JIS K7210-1:2014 under conditions of 190°C and a load of 2.16 kg. If the resin composition does not flow at 190°C, measurement is impossible and is marked with "X". If it is 55 or higher, it is marked with "O".

[0074] [Hardness] Type A durometer hardness Three 2 mm thick test sheets 1 were stacked (total 6 mm) after being left in a room at a temperature of 23°C and a humidity of 50% for one day to condition the sheets. The Type A durometer hardness was measured 3 seconds after the start of measurement in accordance with JIS K6253-3:2012. A value of 80 or higher is considered "hard."

[0075] [Ductility (winding speed at break)] Ductility was evaluated as an index of thin film moldability. Ductility is an index of thermoformability, blow moldability, foam moldability, etc., and an improvement in ductility can be considered as an improvement in molding processability. Ductility was measured as follows. Using a Capilograph 1D PMD-C (Toyo Seiki Seisakusho, Ltd.), extrusion was performed at a piston extrusion speed of 10 mm / min, and the winding speed [m / min] at which the strand broke was read. The die hole diameter was 1.0 mm, and the temperature was 170°C. Seven measurements were performed, and the median value was taken as the ductility value.

[0076] [Flow Start Temperature and Weldable Temperature] Measurements were performed using a flow tester (Shimadzu Corporation, product name: CFT-500D) with a die having a length of 10 mm and a hole diameter of 1.0 mm. 1.7 g of a film of the resin composition was weighed and placed in the measuring device. After that, the temperature at which the resin started to flow under conditions of a load of 15 kgf and a temperature rise rate of 5°C / min was defined as the flow start temperature of each sample. The temperature obtained by this measurement + 15°C was defined as the weldable temperature.

[0077] [Tension at 100% Elongation and Stress at 100% Elongation] The tension at 100% elongation and stress at 100% elongation were measured using a tensile tester (Shimadzu Corporation's Autograph Tensile Tester (AGX-V)). Strip test specimens measuring 5 mm wide and 80 mm long were prepared, with marked lines at 20 mm intervals in the center. One end of the test specimen was fixed with a fixed jig (chuck) and the other end was fixed with a movable jig (chuck). The measured tension at 100% elongation was recorded as the value (N) of the tension at 100% elongation for each sample. The tension at 100% elongation per cross-sectional area was also determined, and the stress at 100% elongation (MPa) was also calculated.

[0078] [Recovery Rate A of Elastic Tape Length After 100% Elongation Repeated Three Times at Room Temperature] The cycle test at 100% elongation was performed using a tensile tester (Shimadzu Corporation's Autograph Tensile Tester (AGX-V)). A strip test piece measuring 5 mm wide and 80 mm long was prepared, with marks at 20 mm intervals in the center. One end of the test piece was fixed with a fixed jig (chuck) and the other end was fixed with a movable jig (chuck). The test piece was stretched at a speed of 300 mm / min until the distance between the marks reached 40 mm (100% elongation), and then the test piece was returned to the initial chuck position at a speed of 300 mm / min, and this operation was repeated three times. The test piece was removed from the device, and the length between the marks after the three-cycle elongation test was measured. From the results obtained, the recovery rate (recovery rate A) of the elastic tape length after three repeated 100% elongation at room temperature was calculated according to the following formula: Recovery rate A (%) = (1-(L β -L α ) / L α ) x 100 L α: Initial gauge length (20 mm) L β : Gauge distance after 3-cycle elongation test (mm)

[0079] [Recovery Rate B of Elastic Tape Length After Holding in 50% Elongation State at 35°C for 2 Hours] A strip test piece measuring 5 mm wide x 80 mm long was prepared, and marked lines were provided at 20 mm intervals in the center. One end of the test piece was fixed with a fixed jig (chuck), and the other end was fixed with a movable jig (chuck), and the test piece was stretched and fixed until it was 50% elongated (30 mm between the marked lines). After leaving it to stand in an oven at 35°C for 2 hours, the elongation stress was released, and it was allowed to cool at room temperature of 25°C for 10 minutes, and the length between the marked lines was measured. From the obtained results, the recovery rate of the elastic tape length (recovery rate B) after holding in a 50% elongation state at 35°C for 2 hours was calculated according to the following formula: Recovery rate B (%) = (1 - (L １ -L ０ ) / L ０ ) x 100 L ０ : Initial gauge length (20 mm) L １ : Gauge distance (mm) after keeping at 35°C for 2 hours

[0080] [Thickness] The thickness was measured by the micrometer method in accordance with 7.4.1.1 of JIS C2330 (2001).

[0081] Example 1 A copolymer (a1) (SEPTON 4033 manufactured by Kuraray, styrene content: 30% by mass, Mw: 92,000, hardness: 76A) of 70 parts by mass and a copolymer (a2) ("SEPTON 2002" manufactured by Kuraray, styrene content: 30% by mass, Mw: 54,000, MFR: 70 g / 10 min, hardness: 80A) of 30 parts by mass were mixed with 80 parts by mass of a hydrocarbon-based softener (b1) (PW-100G manufactured by Idemitsu, paraffin oil) and a styrene-containing oligomer. 10 parts by mass of (c1) (FTR2140 manufactured by Mitsui Chemicals, α-methylstyrene-styrene copolymer, weight average molecular weight 3,230) and 7 parts by mass of polyolefin resin (d1) (Evolue SP1071C manufactured by Prime Polymer Co., Ltd., C6-LLDPE, MFR: 10 g / 10 min (230°C, 2.16 kg load), melting point 112°C, metallocene catalyst) were kneaded at 200°C using a twin-screw extruder to obtain resin composition 1.

[0082] Resin composition 1 was placed in an extrusion lamination molding machine (T-die type single layer extrusion lamination film forming machine, diameter 40 mm, L / D = 24), and extruded at an extrusion temperature of 200°C to obtain an elastic sheet 1 having a thickness of 75 μm.

[0083] [Example 2] Resin composition 1 obtained in the same manner as in Example 1 was placed in an extrusion lamination molding machine (T-die type single-layer extrusion lamination film-forming machine, aperture 40 mm, L / D = 24), and resin composition 1 was extruded at an extrusion temperature of 200°C to obtain a stretchable sheet 2 having a thickness of 150 μm.

[0084] Example 3 A stretchable sheet 3 having a thickness of 75 μm was obtained in the same manner as in Example 1, except that the hydrocarbon-based softener (b1) (PW-100G manufactured by Idemitsu, paraffin oil) was replaced with a hydrocarbon-based softener (b2) (PW-380 manufactured by Idemitsu, hydrogenated paraffin oil, high viscosity oil).

[0085] Example 4 A stretchable sheet 4 having a thickness of 75 μm was obtained in the same manner as in Example 1, except that the styrene-containing oligomer (c1) (FTR2140 manufactured by Mitsui Chemicals, Inc., an α-methylstyrene-styrene copolymer) was replaced with a styrene-containing oligomer (c2) (Crystalex 5140 manufactured by EASTMAN, a weight average molecular weight of 4,900).

[0086] Example 5 A stretchable sheet 5 having a thickness of 75 μm was obtained in the same manner as in Example 1, except that copolymer (a1) (SEPTON 4033 manufactured by Kuraray, styrene content: 30% by mass, Mw: 92,000, hardness 76A) was replaced with copolymer (a3) ​​(TAIPOL 6150 manufactured by TSRC, styrene content: 29% by mass, Mw: 90,000, hardness 76A).

[0087] Example 6 A stretchable sheet 6 having a thickness of 75 μm was obtained in the same manner as in Example 5, except that copolymer (a2) ("SEPTON 2002" manufactured by Kuraray, styrene content: 30% by mass, Mw: 54,000, MFR: 70 g / 10 min, hardness 80 A) was replaced with copolymer (a4) (TAIPOL 6152 manufactured by TSRC, styrene content: 29% by mass, Mw: 55,000, hardness 76 A).

[0088] Example 7 A stretchable sheet 7 having a thickness of 75 μm was obtained in the same manner as in Example 1, except that the polyolefin resin (d1) (Evolue SP1071C, C6-LLDPE, MFR: 10 g / 10 min (230°C, 2.16 kg load), melting point 112°C, manufactured by Prime Polymer Co., Ltd.) was changed to polyolefin resin (d2) (Neozex 2015M, solution process C4-LLDPE, MFR: 1.2 g / 10 min (230°C, 2.16 kg load), melting point 121°C, manufactured by Prime Polymer Co., Ltd.).

[0089] Examples 8 to 20 Stretch sheets 8 to 20 with a thickness of 75 μm were obtained in the same manner as in Example 1, except that the composition of each component was changed as shown in Tables 1 and 2.

[0090] Example 21 A stretchable sheet 21 having a thickness of 75 μm was obtained in the same manner as in Example 1, except that the copolymer (a1) in Example 11 (SEPTON 4033 manufactured by Kuraray, styrene content: 30% by mass, Mw: 92,000, hardness 76A) was replaced with copolymer (a1′) (SEPTON 4044 manufactured by Kuraray, styrene content: 30% by mass, Mw: 92,000, hardness 76A).

[0091] Comparative Examples 1 to 3 Stretch sheets were obtained in the same manner as in Example 1, except that the composition of each component was changed as shown in Table 2. The copolymer (a5) was "SEPTON 4055" manufactured by Kuraray, with a styrene content of 30% by mass and an Mw of 298,000. The hardness could not be measured.

[0092] Comparative Example 4 A resin composition was obtained by changing the composition of each component as shown in Table 2. The obtained resin composition was charged into an extrusion lamination molding machine (T-die type single-layer extrusion lamination film forming machine, aperture 40 mm, L / D = 24) and extruded at an extrusion temperature of 200°C to form a sheet with a thickness of 200 μm. A water-resistant, fabric-less double-sided adhesive sheet (HJ-9150W manufactured by Nitto Denko) with a release paper attached to one side was attached to one side of the sheet. Next, the obtained sheet was processed using a carbon dioxide laser processing machine (EFL1300 model) manufactured by Els Engineering to obtain a mesh film with a diameter of 1 mm.

[0093] Comparative Examples 5 to 8 Stretchable sheets were obtained in the same manner as in Example 11, except that the composition of each component was changed as shown in Table 2.

[0094]

[0095]

[0096] The hardness, melt flow rate, flow initiation temperature, fusion temperature and take-up speed at break of the resin compositions obtained in the examples and comparative examples were measured according to the methods described above.

[0097] The thickness, tension at 100% elongation, stress at 100% elongation, recovery rate A, and recovery rate B of the stretch sheets obtained in the examples and comparative examples were measured according to the methods described above. The results are shown in Tables 1 and 2.

[0098] [Clothing Pressure] The 75 μm thick films of Example 1 and Comparative Example 2 were cut into 1.2 cm × 80 cm pieces, and a plain knit fabric (140 g / m2) was applied to both sides of the pieces. ２ The band was then heat-sealed (temperature 160°C x pressure 0.1 MPa x time 20 seconds) to a sheet of fabric (composition ratio: polyester / polyurethane = 83 / 17). Both ends were then sewn to create a band with a width of 1.2 cm and a circumference of 75 cm. As a proxy characteristic for wearing comfort, the band was worn on the abdomen of a mannequin with a waist size of 80 cm using a clothing pressure measuring device (manufactured by AMI Techno Co., Ltd., model number AMI3037-10) in an environment with a room temperature of 25°C and a relative humidity of 50%. An air pack was placed between the mannequin and the band, and air (approximately 0.3 cm ３ The pressure was measured when the sintered body was sealed in the container, and the results are shown in Table 3.

[0099]

[0100] Although the stretch sheets described in Examples 1 to 21 have low tension at 100% elongation, they have a high length recovery rate (recovery rate A) after three repeated 100% elongations at room temperature. Garments using these stretch sheets have sufficient stretchability despite low stress, resulting in little constriction, as shown in Table 3. Furthermore, the stretch sheets described in Examples 1 to 21 also have a high length recovery rate (recovery rate B) after being held in a 50% elongated state at 35°C for two hours. Garments using these stretch sheets are resistant to repeated stretching and are less likely to sag. In contrast, the stretch sheets of Comparative Examples 1 to 3, 5, and 8 provide a tight fit when used in garments, as shown in Table 3. Furthermore, the stretch sheets of Comparative Examples 1 to 8 also have a low recovery rate B and are prone to sagging. Comparative Examples 4 to 5 and 8 have poor extensibility, and sheets with thicknesses of less than 100 μm could not be obtained.

Claims

1. An elastic sheet having a thickness of 200 μm or less, which is formed from a resin composition containing: a block copolymer (a) containing a polymer block A mainly made of a vinyl aromatic compound and a polymer block B mainly made of a conjugated diene compound, or a hydrogenated copolymer thereof; 50 to 200 parts by mass of a hydrocarbon-based softener (b) and 5 to 20 parts by mass of a styrene-containing oligomer (c) per 100 parts by mass of the copolymer (a).

2. The stretchable sheet according to claim 1, having a tension of 1.5 N / 5 mm or less at 100% elongation.

3. The stretchable sheet according to claim 1 or 2, wherein the total amount of the copolymer (a), the hydrocarbon-based softener (b) and the styrene-containing oligomer (c) is 85 mass% or more based on the total amount of the resin composition.

4. The stretchable sheet according to any one of claims 1 to 3, wherein the resin composition has a flow initiation temperature of 200°C or lower.

5. The stretchable sheet according to any one of claims 1 to 4, which is heat-sealable at a temperature of 170°C or less.

6. The stretch sheet according to any one of claims 1 to 5, wherein the weight average molecular weight of the copolymer (a) is 50,000 to 140,000.

7. The stretch sheet according to any one of claims 1 to 6, wherein copolymer (a) contains a structural unit derived from a styrene-based monomer, and the amount of the structural unit derived from the styrene-based monomer is 15 mass% or more based on the amount of all structural units of copolymer (a).

8. The stretch sheet according to any one of claims 1 to 7, wherein the weight average molecular weight of the styrene-containing oligomer (c) is 1,000 to 6,000.

9. The stretchable sheet according to any one of claims 1 to 8, wherein the resin composition further contains 1 to 50 parts by mass of a polyolefin resin (d) per 100 parts by mass of the copolymer (a).

10. The stretch sheet according to claim 9, wherein the polyolefin resin (d) has a melt flow rate of 0.1 to 100 g / 10 min.

11. Polyolefin resin (d) is a copolymer of ethylene and at least one C ３－ C １２ The stretch sheet according to claim 9 or 10, which is a copolymer with an α-olefin.

12. The stretch sheet according to any one of claims 1 to 11, wherein the amount of the acrylic block copolymer in the resin composition is 0 parts by mass or more and less than 20 parts by mass per 100 parts by mass of copolymer (a).

13. A stretch sheet according to any one of claims 1 to 12, which has a length recovery rate of 99.0% or more after 100% elongation is repeated three times at room temperature.

14. A stretchable sheet according to any one of claims 1 to 13, which has a length recovery rate of 87.0% or more after being held in a 50% elongated state at 35°C for 2 hours.

15. The stretchable sheet according to any one of claims 1 to 14, which is a stretchable tape.

16. A laminate comprising at least an elastic substrate layer (1) and a resin layer (2) adjacent to the elastic substrate layer, the resin layer (2) being a layer formed from the elastic sheet according to any one of claims 1 to 15.

17. The laminate according to claim 16, in which the elastic substrate layer (1) is adjacent to both sides of the resin layer (2).

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