JP2005232246A - Thermoplastic polymer composition having excellent stretchability and its molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic polymer composition which has a small tensile stress relaxation rate and a tensile permanent elongation under a high temperature condition (for example, 70°C) and has excellent stretchability, and to provide a molded article comprising the same. <P>SOLUTION: This thermoplastic polymer composition having excellent stretchability comprises (a) 100 pts. mass of an α-methylstyrene-based block copolymer having a polymer block A consisting mainly of α-methylstyrene units and a polymer block B consisting mainly of conjugated diene units and having a number-average mol. wt. of 30,000 to 500,000 and/or its hydrogenation product, and (b) ≤200 pts. mass of a softener for non-aromatic rubbers. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is a thermoplastic polymer composition excellent in stretchability, having a low tensile stress relaxation rate and a tensile permanent elongation, having stretchability and flexibility close to vulcanized rubber, and small performance degradation even under high temperature conditions. And a molded body thereof.

  Thermoplastic elastomers do not require a vulcanization process and can be molded in the same way as thermoplastic resins. In recent years, such as automotive parts, home appliance parts, electric wire coverings, medical parts, building material parts, footwear, sundries, etc. Used in a wide range of fields. On the other hand, in the field of stretchable materials, thermoplastic elastomers that have rubber elasticity at room temperature and that can be easily plasticized and melted by heating to be molded and that can be recycled are used as sanitary materials and medical materials. , Belt materials, band materials, miscellaneous goods and so on.

  Among thermoplastic elastomers, styrene-based thermoplastic elastomers, which are styrene-conjugated diene block copolymers or their hydrogenated products, are characterized by excellent flexibility, moldability, etc., low specific gravity, and recyclability. Therefore, in recent years, it has been used in a wide range of fields as a substitute for vulcanized rubber and polyvinyl chloride in combination with problems such as environmental pollution.

With respect to stretchable materials using styrene-based thermoplastic elastomers, various proposals have been made for the purpose of further improving molding processability and stretchability. For example, [1] a polymer mainly composed of a vinyl aromatic compound. A hydrogenated block copolymer comprising a hydrogenated block copolymer obtained by hydrogenating a block copolymer having at least two blocks A and at least two polymer blocks B mainly composed of a conjugated diene compound, and fibers made of polyolefin. Copolymer and polyolefin have specific weight ratios and are composed of ultrafine fibers with an average fiber diameter of 10 μm or less. Excellent stretch properties (elongation, stretch recovery), strength (water pressure resistance), and light resistance. A stretchable nonwoven fabric having a soft texture (see Patent Document 1); [2] mainly composed of a vinyl aromatic compound At least two polymer blocks A, at least two polymer blocks B mainly composed of a conjugated diene compound, and at least one polymer block B is at the end of the polymer chain, and the total number average molecular weight And a stretchable nonwoven fabric excellent in elongation characteristics, etc., comprising thermoplastic fibers produced from a hydrogenated block copolymer having a vinyl aromatic compound content in a specific range (see Patent Document 2); [3] (A) a thermoplastic polymer having a polar functional group such as a polyamide-based resin or a polyester-based resin, and (b) a block copolymer comprising a vinyl aromatic compound polymer block and a conjugated diene compound polymer block, and / or Block grafts in which the hydride or the copolymer is a trunk part, and the graft part is a radical decay type polymer A modified block copolymer in which a molecular unit containing a functional group that binds or interacts with the thermoplastic polymer (a) (for example, a unit group based on maleic anhydride) is bound to the copolymer; Or the stretchable nonwoven fabric (refer patent document 3) etc. which are excellent in the stretch recovery property, a softness | flexibility, light resistance, etc. which are formed from the thermoplastic polymer composition containing a modified block * graft copolymer are mentioned.
In recent years, cases in which thermoplastic elastomers are used under high temperature conditions (for example, 70 ° C.) are increasing, and the demand for materials that can maintain performance even under such high temperature conditions tends to increase.

JP-A-3-130448 JP-A-2-259151 JP-A-63-203857

  However, the stretchable materials (stretchable nonwoven fabrics) described in Patent Documents 1 to 3 are not necessarily satisfactory in performance such as tensile stress relaxation rate and tensile permanent elongation under high temperature conditions (for example, 70 ° C.). There was still room for improvement in these performances.

  Thus, the object of the present invention is to solve such problems, to reduce the tensile stress relaxation rate and the tensile permanent elongation, to have stretchability and flexibility close to vulcanized rubber, and to be used under high temperature conditions (for example, 70 It is an object to provide a thermoplastic polymer composition excellent in stretchability and a molded product thereof, in which performance degradation is small even at (° C.).

According to the present invention, the above object is (a) the number average molecular weight having a polymer block A mainly composed of α-methylstyrene units and a polymer block B mainly composed of conjugated diene units is in the range of 30,000 to 500,000. A thermoplastic polymer composition excellent in elasticity, comprising 100 parts by mass of an α-methylstyrene block copolymer and / or a hydrogenated product thereof, and (b) 200 parts by mass or less of a softener for non-aromatic rubber. Achieved by providing.
As a preferred embodiment of the present invention, in addition to the above composition, (c) polyolefin resin, polystyrene resin, polyphenylene ether resin, polycarbonate resin, polyvinyl chloride resin, polyvinyl acetate resin, polyester resin, polyamide The thermoplastic polymer composition excellent in the elasticity which contains at least 1 type of a system resin in the ratio of 100 mass parts or less with respect to 100 mass parts of block copolymers (a) is included.
In the present invention, the block copolymer (a) is (1) a polymer block A mainly composed of α-methylstyrene having a number average molecular weight of 1,000 to 50,000, and (2) a number average molecular weight of 1,000 to 30,000. The conjugated diene unit constituting the block has a block b1 in which the 1,4-bond amount is less than 30% and the number average molecular weight is 10,000 to 400,000, and the conjugated diene unit constituting the block has 1, 4- Polymer having a block b2 having a bond amount of 30% or more and having at least one (A-b1-b2) structure, and having excellent stretch properties as described above A polymer composition is included as a preferred embodiment.

  According to the present invention, it is possible to provide a thermoplastic polymer composition excellent in stretchability such as tensile stress relaxation rate and tensile permanent elongation under high temperature conditions (for example, 70 ° C.). The thermoplastic polymer composition excellent in stretchability of the present invention does not contain substances that cause environmental pollution, and is used in a wide range of applications such as stretchable fibers, films, strips, nonwoven fabrics, etc. In particular, it can be suitably used for sanitary materials such as disposable diapers and sanitary products.

The present invention is described in detail below.
The block copolymer (a) constituting the thermoplastic polymer composition of the present invention includes a polymer block A mainly composed of α-methylstyrene and a hydrogenated polymer mainly composed of conjugated diene. A block copolymer having a block B and having a number average molecular weight of 30,000 to 500,000. The number average molecular weight of the block copolymer (a) is more preferably in the range of 35,000 to 400,000, and further preferably in the range of 40000 to 300,000. When the number average molecular weight of the block copolymer (a) is less than 30,000, the stretchability of the molded product obtained from the thermoplastic polymer composition is lowered, whereas when it exceeds 500,000, the thermoplastic polymer The molding processability of the composition is inferior. In addition, the number average molecular weight here means the weight average molecular weight in terms of polystyrene determined by gel permeation chromatography (GPC) measurement.

  In such a block copolymer (a), the polymer block A is preferably composed only of structural units derived from α-methylstyrene. However, the polymer block A is an unsaturated monomer other than α-methylstyrene, such as butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 3-pentadiene, 1,3-hexadiene, isobutylene, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, pt-butylstyrene, 2,4-dimethylstyrene, vinylnaphthalene, vinylanthracene, methacryl A small amount of one or more structural units derived from methyl acid, methyl vinyl ether, N-vinyl carbazole, β-pinene, 8,9-p-mentene, dipentene, methylene norbornene, 2-methylene tetrahydrofuran, The range of 10% by mass or less as a ratio with respect to the polymer block A You may have.

The content of the polymer block A in the block copolymer (a) is preferably in the range of 5 to 45% by mass from the viewpoint of the tensile stress relaxation rate and the tensile permanent elongation of the thermoplastic polymer composition. More preferably, it is in the range of ˜40 mass%. The content of the polymer block A in the block copolymer (a), for example, can be determined by such ^{1 H-NMR} spectrum.

  The polymer block B in the block copolymer (a) is mainly composed of a structural unit derived from a conjugated diene and may be hydrogenated. Examples of the conjugated diene constituting the polymer block B include butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, and the like. B may be composed of one kind of these conjugated dienes, or may be composed of two or more kinds. Among these, the polymer block B is preferably composed of butadiene, isoprene or a mixture of butadiene and isoprene.

  When the polymer block B is composed of two or more kinds of conjugated dienes (for example, butadiene and isoprene), their bonding form is not particularly limited, and is random, tapered, completely alternating, partially blocky or their It can consist of a combination of two or more.

  In addition, the polymer block B may contain other unsaturated monomers such as styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methyl, as long as the object and effect of the present invention are not hindered. Styrene, pt-butylstyrene, 2,4-dimethylstyrene, vinylnaphthalene, vinylanthracene, methyl methacrylate, methyl vinyl ether, N-vinylcarbazole, β-pinene, 8,9-p-mentene, dipentene, methylene norbornene One or more structural units derived from 2-methylenetetrahydrofuran or the like may be contained in a small amount, preferably in a range of 10% by mass or less as a ratio to the polymer block B.

From the viewpoint of heat resistance and weather resistance, the polymer block B in the block copolymer (a) is hydrogenated (hydrogenated) at least 50 mol% of the carbon-carbon double bond based on the conjugated diene unit. More preferably, 70 mol% or more is hydrogenated, and more preferably 90 mol% or more is hydrogenated. In addition, said hydrogenation rate is based on the content of the carbon-carbon double bond based on the conjugated diene unit in the polymer block B, before and after hydrogenation, iodine value measurement, infrared spectrophotometer, ¹ H- It can be measured from an NMR spectrum or the like and obtained from the measured value.

  As long as the polymer block A and the polymer block B are bonded to the block copolymer (a), the bonding type is not limited, and is linear, branched, radial, or two or more thereof Any of the combined forms may be used. Among them, it is preferable that the bond form of the polymer block A and the polymer block B is a linear form, for example, when the polymer block A is represented by A and the polymer block B is represented by B. Further, a triblock copolymer represented by A-B-A, a tetrablock copolymer represented by A-B-A-B, a pentablock copolymer represented by A-B-A-B-A, etc. Can be mentioned. Especially, a triblock copolymer (ABA) is used preferably from points, such as the ease of manufacture of a block copolymer (a), and a softness | flexibility.

  The block copolymer (a) has one kind of functional group such as a carboxyl group, a hydroxyl group, an acid anhydride group, an amino group, and an epoxy group in the molecular chain and / or at the molecular end unless the purpose of the present invention is impaired. Or you may have 2 or more types. Moreover, you may mix and use the block copolymer (a) which has an above described functional group, and the block copolymer (a) which does not have a functional group as a block copolymer (a).

The block copolymer (a) can be produced by an anionic polymerization method, and the following specific synthesis examples are shown. (1) α-methylstyrene after polymerization of a conjugated diene using a dianionic initiator such as 1,4-dilithio-1,1,4,4-tetraphenylbutane in a tetrahydrofuran solvent and then at −78 ° C. Is obtained by sequential polymerization to obtain a triblock copolymer represented by A-B-A (see Macromolecules, Vol. 2, pages 453-458 (1969)), (2) cyclohexane, etc. After α-methylstyrene is polymerized with an anionic polymerization initiator such as sec-butyllithium in a nonpolar solvent, conjugated dienes are polymerized, and then coupling agents such as tetrachlorosilane and diphenyldichlorosilane (α, α '-Dichloro-p-xylene, phenyl benzoate, etc. can also be used) to carry out the coupling reaction. (A-B) Method for obtaining an nX-type block copolymer (Kautschuk Gumi Kunststoff, 37, 377-379 (1984); Polymer Bullin, 12 71-77 (1984)), (3) In a nonpolar solvent, an organic lithium compound is used as an initiator, and in the presence of a polar compound having a concentration of 0.1 to 10% by mass, the temperature is -30 to 30 ° C. At temperature, α-methylstyrene having a concentration of 5 to 50% by mass is polymerized, a conjugated diene is polymerized to the resulting living polymer, a coupling agent is added, and ABA type block copolymer (4) Presence of a polar compound having a concentration of 0.1 to 10% by mass using an organolithium compound as an initiator in a nonpolar solvent The α-methylstyrene polymer having a concentration of 5 to 50% by mass is polymerized at a temperature of −30 to 30 ° C., the conjugated diene is polymerized to the resulting living polymer, and the resulting α-methylstyrene polymer block and the conjugated diene are obtained. A method of obtaining an ABC type block copolymer by polymerizing an anion polymerizable monomer other than α-methylstyrene to a living polymer of a block copolymer comprising polymer blocks.
Among the specific methods for producing the block copolymer, the methods (3) and (4) are preferred, and the method (3) is particularly preferred. The above method will be specifically described below.

  Examples of the organic lithium compound used as an initiator in the above method include monolithium compounds such as n-butyllithium, sec-butyllithium and tert-butyllithium, and dilithium compounds such as tetraethylenedilithium. These compounds may be used alone or in combination of two or more.

  The solvent used in the polymerization of α-methylstyrene is a nonpolar solvent, such as aliphatic hydrocarbons such as cyclohexane, methylcyclohexane, n-hexane, n-heptane, aromatic hydrocarbons such as benzene, toluene, xylene, etc. Can be mentioned. These nonpolar solvents may be used alone or in combination of two or more.

The polar compound used in the polymerization of α-methylstyrene is a compound that does not have a functional group (hydroxyl group, carbonyl group, etc.) that reacts with anionic species and has a hetero atom such as an oxygen atom or a nitrogen atom in the molecule. For example, diethyl ether, monoglyme, tetramethylethylenediamine, dimethoxyethane, tetrahydrofuran and the like can be mentioned. These polar compounds may be used alone or in admixture of two or more.
The concentration of the polar compound in the reaction system is such that α-methylstyrene is polymerized at a high conversion rate, and the amount of 1,4-bond in the conjugated diene polymer block is controlled when the subsequent conjugated diene is polymerized. To 0.1 to 10% by weight, and more preferably 0.5 to 3% by weight.

  The α-methylstyrene concentration in the reaction system is preferably in the range of 5 to 50% by mass from the viewpoint of the viscosity of the reaction solution in the latter stage of polymerization by polymerizing α-methylstyrene at a high conversion rate. A range of 40% by mass is more preferred.

  The above conversion rate means the ratio of unpolymerized α-methylstyrene converted into a polymer by polymerization, and in the present invention, the degree is preferably 70% or more, and 85% or more. More preferably.

  The temperature conditions during the polymerization of α-methylstyrene are the ceiling temperature of α-methylstyrene (the temperature at which the polymerization reaction reaches an equilibrium state and does not proceed substantially), the polymerization rate of α-methylstyrene, the living property, etc. From this point, it is preferably within the range of -30 to 30 ° C, more preferably -20 to 10 ° C, and further preferably -15 to 0 ° C. By setting the polymerization temperature to 30 ° C. or less, α-methylstyrene can be polymerized at a high conversion rate, and the proportion of the living polymer to be deactivated is small, so that homopoly α- Suppresses the mixing of methylstyrene and does not impair physical properties. In addition, by setting the polymerization temperature to −30 ° C. or higher, the reaction solution can be stirred without increasing the viscosity in the latter stage of polymerization of α-methylstyrene, and the cost necessary to maintain the low temperature state does not increase. Economically preferable.

  In the above method, as long as the characteristics of the α-methylstyrene polymer block are not impaired, another vinyl aromatic compound may coexist at the time of polymerization of α-methylstyrene, and this may be copolymerized with α-methylstyrene. . Examples of the vinyl aromatic compound include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, 2,4-dimethyl styrene, vinyl naphthalene, and vinyl anthracene. A vinyl aromatic compound may be used independently or may be used 2 or more types.

  Living poly α-methylstyryl lithium is produced by polymerization of α-methylstyrene using an organolithium compound as an initiator, and this is then polymerized with a conjugated diene. Examples of the conjugated diene include butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, and the like. These conjugated dienes may be used alone or in combination of two or more. Of these, butadiene and isoprene are preferable, and these may be used in combination.

  The conjugated diene is subjected to polymerization by being added to the reaction system. The method for adding the conjugated diene to the reaction system is not particularly limited, and the conjugated diene may be added directly to the living poly α-methylstyryllithium solution or diluted with a solvent. As a method of diluting a conjugated diene in a solvent, the conjugated diene may be added and then diluted with a solvent, the conjugated diene and the solvent may be added simultaneously, or the conjugated diene may be added after diluting with a solvent. Good. Suitably, an amount of conjugated diene corresponding to 1 to 100 molar equivalents, preferably 5 to 50 molar equivalents of living poly α-methylstyryl lithium is added and polymerized to form a conjugated diene block (hereinafter referred to as a heavy polymer). (Sometimes referred to as coalescing block b1) and the living active terminal is variably diluted, then diluted with a solvent, and then charged with the remaining conjugated diene, at a temperature above 30 ° C., preferably 40-80 ° C. A method in which a polymerization reaction is carried out in a range to further form a conjugated diene block (hereinafter sometimes referred to as polymer block b2) is recommended. When changing the active terminal of living poly α-methylstyryllithium, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, vinylnaphthalene, vinyl instead of conjugated diene Vinyl aromatic compounds such as anthracene and 1,1-diphenylethylene may be used.

  Examples of the solvent that can be used for dilution include aliphatic hydrocarbons such as cyclohexane, methylcyclohexane, n-hexane, and n-heptane, and aromatic hydrocarbons such as benzene, toluene, and xylene. . These solvents may be used alone or in combination of two or more.

  For example, a polyfunctional coupling agent is added to a living polymer of a block copolymer comprising an α-methylstyrene polymer block and a conjugated diene polymer block obtained by copolymerizing a conjugated diene with living poly α-methylstyryl lithium. By reacting, a triblock or radial teleblock type block copolymer (a) can be produced. The block copolymer in this case is a mixture containing diblock, triblock, and radial teleblock block copolymers at an arbitrary ratio, which is obtained by adjusting the amount of the polyfunctional coupling agent used. May be. Examples of multifunctional coupling agents include phenyl benzoate, methyl benzoate, ethyl benzoate, ethyl acetate, methyl acetate, methyl pivalate, phenyl pivalate, ethyl pivalate, α, α′-dichloro-o-xylene, α, α′-dichloro-m-xylene, α, α′-dichloro-p-xylene, bis (chloromethyl) ether, dibromomethane, diiodomethane, dimethyl phthalate, dichlorodimethylsilane, dichlorodiphenylsilane, trichloromethylsilane, Examples include tetrachlorosilane and divinylbenzene. In addition, what is necessary is just to adjust the usage-amount of a polyfunctional coupling agent suitably according to the number average molecular weight of a block copolymer (a), and there is no restriction | limiting in a strict meaning.

  A triblock or radial teleblock type block copolymer (a) obtained by reacting a living polymer of a block copolymer comprising an α-methylstyrene polymer block and a conjugated diene polymer block with a polyfunctional coupling agent (a ) Is hydrogenated (hydrogenated), an active hydrogen compound such as alcohols, carboxylic acids, or water is added as necessary to stop the coupling reaction. By hydrogenation in the presence of a hydrogenation catalyst in an active organic solvent, a hydrogenated block copolymer (a) can be obtained.

  In addition, when hydrogenating a block copolymer (a) comprising an α-methylstyrene polymer block and a conjugated diene polymer block, alcohols are obtained after polymerizing the conjugated diene with living poly α-methylstyryl lithium. Then, an active hydrogen compound such as carboxylic acids and water is added to stop the polymerization reaction, and hydrogenated in the presence of a hydrogenation catalyst in an inert organic solvent according to a known method to be described later, a hydrogenated block It can be set as a copolymer (a).

  Unfunctionalized non-hydrogenated block copolymer consisting of α-methylstyrene polymer block and conjugated diene polymer block, or living polymer of block copolymer consisting of α-methylstyrene polymer block and conjugated diene polymer block An unhydrogenated triblock or radial teleblock type block copolymer (both included in the block copolymer (a) used in the present invention) obtained by reacting a reactive coupling agent is produced Without replacing the solvent used in the above, it can be directly subjected to hydrogenation.

  In the hydrogenation reaction, Raney nickel; a heterogeneous catalyst in which a metal such as Pt, Pd, Ru, Rh, Ni is supported on a carrier such as carbon, alumina, diatomaceous earth; transition metal compound (nickel octylate, nickel naphthenate, Ziegler-based catalyst comprising a combination of nickel acetylacetonate, cobalt octylate, cobalt naphthenate, cobalt acetylacetonate, etc.) and an organoaluminum compound or organolithium compound such as triethylaluminum or triisobutylaluminum; titanium, zirconium, hafnium Of hydrogenation catalysts such as metallocene catalysts composed of combinations of transition metal bis (cyclopentadienyl) compounds and organometallic compounds composed of lithium, sodium, potassium, aluminum, zinc or magnesium The standing down, it can be carried out usually at a reaction temperature 20 to 100 ° C., under the conditions of a range of hydrogen pressure 0.1 to 10 MPa. The unhydrogenated block copolymer (a) is desirably hydrogenated until 70% or more, particularly preferably 90% or more of the carbon-carbon double bonds in the conjugated diene polymer block B are saturated, Thereby, the weather resistance of a block copolymer (a) can be improved.

  As the block copolymer (a) used in the present invention, those obtained by the above method are preferably used. In particular, an organolithium compound is used as an initiator in a nonpolar solvent, and the concentration is 0.1 to 10% by weight. In the presence of a polar compound, α-methylstyrene having a concentration of 5 to 50% by weight is polymerized at a temperature of −30 to 30 ° C., and then in the polymerization of the conjugated diene, first, 1 to the living poly α-methylstyryllithium. ˜100 molar equivalents of conjugated diene are added and polymerized while changing the living active terminal to form polymer block b1, and then the reaction system is heated to a temperature exceeding 30 ° C. and polymerized by adding conjugated diene and polymerization. It is desirable that the block is obtained by forming the combined block b2 because the stretchability of the block copolymer is excellent in a wide temperature range. That is, in this case, the polymer block B includes the polymer block b1 and the polymer block b2.

  The block copolymer (a) is not limited to a linear or branched structure as its structure, but among them, a block copolymer having at least one (A-b1-b2) structure is preferable. b1-b2-b2-b1-A-type copolymer, A-b1-b2-b2-b1-A-type copolymer and A-b1-b2-type copolymer, (A-b1-b2) nX Type copolymer (X represents a coupling agent residue, n is an integer of 2 or more) and the like.

The number average molecular weight of the polymer block A in the block copolymer (a) is preferably in the range of 1000 to 50000, and more preferably in the range of 2000 to 40000.
The number average molecular weight of the polymer block b1 in the block copolymer (a) is preferably in the range of 1000 to 30000, more preferably in the range of 2000 to 25000, and the polymer block b1 The 1,4-bond amount of the conjugated diene unit constituting is preferably less than 30%.
Further, the number average molecular weight of the polymer block b2 in the block copolymer (a) is preferably in the range of 10,000 to 400,000, more preferably in the range of 20,000 to 300,000, and the polymer block b2 The 1,4-bond amount of the conjugated diene unit constituting is 30% or more, preferably in the range of 35% to 95%, more preferably in the range of 40% to 80%.

  Examples of the non-aromatic rubber softener (b) in the thermoplastic polymer composition of the present invention include hydrocarbon oils such as paraffinic and naphthenic; vegetable oils such as peanut oil and rosin; phosphate esters; Known molecular weight polyethylene glycol; liquid paraffin; low molecular weight polyethylene, ethylene-α-olefin copolymer oligomer, liquid polybutene, liquid polyisoprene or hydrogenated product thereof, and hydrocarbon synthetic oil such as liquid polybutadiene or hydrogenated product thereof Softeners can be used. These may be used alone or in combination of two or more. Among these, in the present invention, hydrocarbon-based synthetic oils such as paraffin-based hydrocarbon oils and ethylene-α-olefin copolymer oligomers are preferably used as the non-aromatic rubber softener (b). The

  In the thermoplastic polymer composition of the present invention, the non-aromatic rubber softener (b) is preferably added in an amount of 200 parts by mass or less with respect to 100 parts by mass of the block copolymer (a), and 150 It is more preferable that the addition amount be less than or equal to part by mass. When the addition amount of the non-aromatic rubber softener (b) is more than 200 parts by mass with respect to 100 parts by mass of the block copolymer (a), the stretchability of the resulting thermoplastic polymer composition is lowered. Becomes larger.

In the thermoplastic polymer composition of the present invention, the component (c) that may be further added as necessary includes polypropylene, high density polyethylene (HDPE), medium density polyethylene, low density polyethylene (LDPE), ethylene- Propylene copolymer, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-heptene copolymer, ethylene-1-octene copolymer, ethylene-4-methyl-1-pentene Copolymer, ethylene-1-α-olefin copolymer such as ethylene-1-nonene copolymer, ethylene-1-decene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene- Acrylic acid ester copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer or this Polyolefin resins such as resins modified with maleic anhydride; polystyrenes such as polystyrene, poly α-methylstyrene, polyparamethylstyrene, acrylonitrile-styrene resin, acrylonitrile-butadiene-styrene resin, maleic anhydride-styrene resin Resin; Polyphenylene ether resin; Polycarbonate resin; Polyvinyl chloride resin; Polyvinyl acetate resin; Polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polylactic acid, polycaprolactone, polyamide 6, polyamide 6,6, polyamide 6・ 10, polyamide 11, polyamide 12, polyamide 6 ・ 12, polyhexamethylenediamine terephthalamide, polyhexamethylenediamine isophthalamide, xylene group Polyamide resins such as polyamide and the like. All of these have solubility parameters (Solubility Parameters of Polymers; hereinafter referred to as SP values) used as a measure of polymer compatibility in the range of 15 to 23 (MPa) ^1/2 . The SP value here is a value calculated from the cohesive energy constant G of atoms and atomic groups, the molecular weight M of the polymer structural unit, and the density ρ of the polymer by the formula: SP value = ρΣG / M. In addition, it is supposed that the polymers having close SP values are basically compatible.

  When the component (c) is further added to the thermoplastic polymer composition of the present invention, the amount added is preferably in the range of 100 parts by mass or less with respect to 100 parts by mass of the block copolymer (a). A range of 80 parts by mass or less is more preferable. When the addition amount of the component (c) exceeds 100 parts by weight with respect to 100 parts by weight of the block copolymer (a), the tensile stress relaxation rate and the tensile permanent elongation increase, and the expansion / contraction performance deteriorates.

  As the component (c), a polyolefin resin, a polystyrene resin, a polyphenylene ether resin, or a polycarbonate resin is used. These resins have excellent compatibility with the block copolymer (a) and are suitable for kneading conditions. However, it is preferable because a thermoplastic polymer composition that exhibits good stretchability is easily obtained. Among them, polystyrene resins, polyphenylene ether resins, and polycarbonate resins are excellent in compatibility with the polymer block A of the block copolymer (a), and exhibit good stretch performance without impairing flexibility. It is more preferable at the point which is easy to obtain a polymer composition.

  The thermoplastic polymer composition of the present invention may further contain a rubber reinforcing agent or a filler, if necessary, as long as the gist of the present invention is not impaired.

  Examples of the rubber reinforcing agent or filler include inorganic fillers such as carbon black, calcium carbonate, talc, silica, and diatomaceous earth; organic fillers such as rubber powder and wood powder. These may be used alone or in combination of two or more. When the rubber reinforcing agent or filler is contained, the content thereof is preferably 30% by mass or less based on the total amount of the thermoplastic polymer composition.

  In addition, the thermoplastic polymer composition of the present invention is a heat stabilizer, an antioxidant, a light stabilizer, a flame retardant, a foaming agent, an antistatic agent, if necessary, as long as the gist of the present invention is not impaired. An agent, a pigment, a crosslinking agent and the like may be further contained.

  The mixing for obtaining the thermoplastic polymer composition of the present invention can be performed by a conventional method. For example, using a kneader such as a single screw extruder, a twin screw extruder, a Banbury mixer, a Brabender, an open roll, or a kneader, the respective constituent components are kneaded to obtain a thermoplastic polymer composition. In general, the kneading temperature is preferably in the range of 160 to 280 ° C, more preferably in the range of 190 to 260 ° C.

  In the above kneading, for example, (1) a method in which all the components constituting the thermoplastic polymer composition are dry-blended in advance using a mixer such as a Henschel mixer or a tumbler before being kneaded and batch-kneaded. (2) After kneading the other components excluding the non-aromatic rubber softener (b) in advance, a predetermined amount of the non-aromatic rubber softener (b) is added to the kneader using a side feeder or the like. Method of adding; (3) A method of adding a predetermined amount of component (c) into a kneader using a side feeder after kneading other components excluding component (c) in advance. May be adopted.

  The thermoplastic polymer composition of the present invention has a tensile stress relaxation rate of 30% when held at 40 ° C. and 50% elongation for 100 minutes in a stress relaxation test described in JIS K 6263 as a measure of excellent stretchability. The tensile stress relaxation rate when held for 10 minutes at 70 ° C. and 50% elongation is 50% or less. When this condition is satisfied, the object of the present invention can be achieved more effectively.

  Various molded articles having stretchability can be prepared from the thermoplastic polymer composition thus obtained. For example, it can be made into the form suitable for each according to a use, such as a fiber, a film, a strip, a strand, and a nonwoven fabric.

  In the present invention, the method of shaping the various molded articles having the above-described stretchability from the thermoplastic polymer composition is not particularly limited, and a general molding method according to the form of the various molded bodies having the stretchability. Can be suitably used.

For example, the device for shaping into a fiber shape may be substantially the same as the device used when melt spinning an ordinary thermoplastic resin. That is, for example, a type in which a gear pump is coupled to a screw extruder may be used. By controlling the spinning temperature, spinning pressure, extrusion speed, spinning hole diameter and winding speed, the denier configuration of the fiber to be produced can be variously changed as in the case of ordinary melt spinning. In order to prevent sticking between the wound fibers, an aqueous surfactant solution or finely divided talc, calcium carbonate, titanium oxide, silica, alumina, etc. are added to the spun yarn before winding. It is preferable to apply a dispersed aqueous solution.
The fiber wound in this manner may be stretched as in the case of ordinary thermoplastic synthetic fibers, but may not be stretched, and steps such as heat treatment can be omitted.

  Moreover, when shape | molding, for example to a film, a strand, or a strip | belt body, it can shape | mold using a single screw extruder or a twin screw extruder. In addition, when forming into a nonwoven fabric, for example, by using an ordinary melt blown nonwoven fabric manufacturing apparatus, melt spinning the thermoplastic polymer composition and forming a fiber web on the collecting surface, the melt blown Nonwoven fabric can be manufactured. The nonwoven fabric can also be produced by a spunbond method in which a fiber web is formed in advance and then heated by a roll or the like to partially bond the fiber contacts.

  As the processing temperature when shaping various molded products having the above-described stretchability from the thermoplastic polymer composition of the present invention, a temperature of 160 to 300 ° C is generally preferable, and a temperature of 170 to 290 ° C is more preferable. .

  When the form of the stretchable molded body is a fiber, its thickness can be arbitrarily selected within a range of several deniers as in the case of ordinary thermoplastic synthetic fibers. The cross-sectional shape of the fiber may be any of a flat cross-section, a polygonal cross-section, a multi-leaf cross-section, a hollow cross-section, etc. in addition to a normal round cross-section.

  When the form of the stretchable molded body is a film, the thickness and width are not particularly limited, but the film thickness is usually preferably in the range of 15 μm to 200 μm. When the shape of the stretchable molded body is a strand, the cross-sectional shape of the strand is not particularly limited, and for example, a shape such as a circle, an ellipse, or a square is preferable. When the shape of the stretchable molded body is a band-like body, the thickness and width are not particularly limited, but usually the thickness of the band-like body is preferably in the range of 200 μm to 2 mm.

When the form of the stretchable molded body is a nonwoven fabric, there is no particular limitation on the fineness, basis weight, etc. of the fibers constituting the nonwoven fabric, and it can be made suitable according to the application. In addition, it is preferable from the point which is excellent in the tensile stress relaxation rate and the tensile permanent elongation that the fiber which comprises this nonwoven fabric is a long fiber with uniform fineness. The basis weight of the nonwoven fabric is preferably in the range of 5 to 200 g / m ² from the viewpoint of handleability.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the content of the present invention is not limited to these examples.
In the following reference examples, the number average molecular weight is a molecular weight in terms of polystyrene by GPC method, and the hydrogenation rate, the content of α-methylstyrene and styrene, and the amount of 1,4-bond are measured by ¹ H-NMR method. did.
In the following examples and comparative examples, the physical properties of the obtained thermoplastic polymer compositions were evaluated by the following methods.

<a> Tensile stress relaxation rate A sheet having a thickness of 2 mm was obtained by press-molding the thermoplastic polymer compositions obtained in Examples and Comparative Examples at 200 ° C. A strip-shaped test piece No. 2 described in JIS K 6263 is punched out from this sheet, and using this test piece, the distance between grips is 20 mm under the measurement conditions set in advance using an Instron universal tensile tester. After measuring the initial tensile stress (m ₀ ) when the test speed was extended by 50% at 300 mm / min, the tensile stress (m ₁ ) when held for a certain period of time was measured. The tensile stress relaxation rate was determined. The measurement conditions were {1} atmosphere temperature 40 ° C., 100 minute hold, and {2} atmosphere temperature 70 ° C., 10 minute hold.
Tensile stress relaxation rate (%) = 100 × (m ₀ -m ₁ ) / m ₀

<B> Tensile Permanent Elongation A sheet having a thickness of 2 mm was obtained by press-molding the thermoplastic polymer compositions obtained in Examples and Comparative Examples at 200 ° C. A strip-shaped test piece No. 2 described in JIS K 6262 was punched from this sheet, a mark line with a width of 2 cm was attached to the test piece, and it was stretched by 50% at an ambient temperature of 25 ° C. or 70 ° C. and held for 2 hours. After 30 minutes, the length between the marked lines (l ₁ (cm)) was measured 30 minutes later, and the tensile permanent elongation was determined by the following equation.
Tensile elongation (%) = 100 × (l ₁ −2) / 2

The contents of each component used in the following examples and comparative examples are as follows.
Block copolymer (a)
Reference example 1
(1) 90.9 g of α-methylstyrene, 138 g of cyclohexane, 15.2 g of methylcyclohexane, and 3.1 g of tetrahydrofuran were charged into a pressure-resistant vessel equipped with a stirrer purged with nitrogen. To this mixed solution, 11.2 ml of sec-butyllithium (1.3 M cyclohexane solution) was added and polymerized at −10 ° C. for 3 hours. When the number average molecular weight of poly α-methylstyrene (Block A) 3 hours after the start of polymerization was measured by GPC, it was 5500 in terms of polystyrene, and the polymerization conversion of α-methylstyrene was 89%. Next, 23.0 g of butadiene was added to the reaction mixture, and the mixture was stirred at −10 ° C. for 30 minutes to polymerize the block b1, and then 930 g of cyclohexane was added. The polymerization addition rate of α-methylstyrene at this time is 89%, the number average molecular weight (GPC measurement, polystyrene conversion) of the polybutadiene block (b1) is 3200, and 1,4 determined from ¹ H-NMR measurement -The binding amount was 19%.
Next, 30.0 g of butadiene was further added to the reaction solution, and a polymerization reaction was performed at 50 ° C. for 2 hours. The number average molecular weight (GPC measurement, polystyrene conversion) of the polybutadiene block (b2) of the block copolymer (structure: A-b1-b2) obtained by sampling at this time is 57000, which is obtained from ¹ H-NMR measurement. The amount of 1,4-bond was 62%.

(2) Subsequently, 14.5 ml of dichlorodimethylsilane (0.5 M toluene solution) was added to this polymerization reaction solution, and the mixture was stirred at 50 ° C. for 1 hour, and poly (α-methylstyrene) -polybutadiene-poly (α -Methylstyrene) triblock copolymer was obtained. The coupling efficiency at this time was determined as follows: coupling body (poly (α-methylstyrene) -polybutadiene-poly (α-methylstyrene) triblock copolymer: A-b1-b2-X-b2-b1-A) It was 93% when calculated from the area ratio of UV absorption in GPC of the unreacted block copolymer (poly (α-methylstyrene) -polybutadiene block copolymer: A-b1-b2). Moreover, as a result of ¹ H-NMR analysis, the α-methylstyrene polymer block content in the poly (α-methylstyrene) -polybutadiene-poly (α-methylstyrene) triblock copolymer was 20%, and butadiene The amount of 1,4-bond in the entire polymer block B (that is, block b1 and block b2) was 60%.

(3) A Ziegler-type hydrogenation catalyst formed from nickel octylate and triethylaluminum is added to the polymerization reaction solution obtained in the above (2) under a hydrogen atmosphere, and a hydrogen pressure of 0.8 MPa at 80 ° C. By performing a hydrogenation reaction for a period of time, a hydrogenated product of poly (α-methylstyrene) -polybutadiene-poly (α-methylstyrene) triblock copolymer (hereinafter abbreviated as block copolymer a-1). Obtained). As a result of GPC measurement of the obtained block copolymer a-1, the main components were Mt (peak top of average molecular weight) = 108000, Mn (number average molecular weight) = 106000, Mw (weight average molecular weight) = 108000, Mw / This is a hydrogenated product (coupling body) of poly (α-methylstyrene) -polybutadiene-poly (α-methylstyrene) triblock copolymer having Mn = 1.02, and the area of UV (254 nm) absorption in GPC From the ratio, it was found that 93% of the coupling body was contained. Moreover, the hydrogenation rate of the butadiene polymer block B comprised from the block b1 and the block b2 was 98% by < ¹ > H-NMR measurement. These results are summarized in Table 1.

Reference example 2
In Reference Example 1, the amount of sec-butyllithium (1.3 M cyclohexane solution) used was changed from 11.2 ml to 5.7 ml, the total amount of butadiene used was changed from 323 g to 164.3 g, and dichlorodimethylsilane (0.5 M toluene solution). ) Was changed from 14.5 ml to 7.4 ml, and other operations were carried out in the same manner as in Reference Example 1 to perform a block copolymer (hereinafter abbreviated as block copolymer a-2). Got. The molecular properties are summarized in Table 1.

Reference example 3
In Reference Example 1, the amount of sec-butyllithium (1.3 M cyclohexane solution) used was changed from 11.2 ml to 9.4 ml, the total amount of butadiene used was changed from 323 g to 164.3 g, and dichlorodimethylsilane (0.5 M toluene solution). ) Was changed from 14.5 ml to 12.2 ml, and other operations were carried out in the same manner as in Reference Example 1 to perform a block copolymer (hereinafter abbreviated as block copolymer a-3). Got. The molecular properties are summarized in Table 1.

Reference example 4
In a pressure vessel equipped with a stirrer purged with nitrogen, 81 g of styrene, 1100 g of cyclohexane, and 3.1 g of tetrahydrofuran were charged. To this solution, 11.2 ml of sec-butyllithium (1.3 M, cyclohexane solution) was added and polymerized at 50 ° C. for 1 hour. Next, 323 g of butadiene was added to the reaction mixture, and polymerization was carried out at 50 ° C. for 1 hour. Thereafter, 14.5 ml of dichlorodimethylsilane (0.5 M, toluene solution) was further added to this reaction mixture, and the mixture was stirred at 50 ° C. for 1 hour, whereby a reaction mixture containing a polystyrene-polybutadiene-polystyrene triblock copolymer was obtained. Obtained. A Ziegler-type hydrogenation catalyst consisting of nickel octylate / triethylaluminum was added to this reaction mixture, and a hydrogenation reaction was carried out at 80 ° C. for 5 hours at a hydrogen pressure of 0.8 MPa. A hydrogenated product of the polymer (hereinafter, abbreviated as block copolymer a-4) was obtained. The molecular properties are summarized in Table 1.

Reference Example 5
In Reference Example 4, the amount of sec-butyllithium (1.3 M cyclohexane solution) used was changed from 11.2 ml to 5.7 ml, the amount of butadiene used was changed from 323 g to 164.3 g, and dichlorodimethylsilane (0.5 M toluene solution). Was changed from 14.5 ml to 7.4 ml, and other operations were carried out in the same manner as in Reference Example 1 to obtain a block copolymer (hereinafter abbreviated as block copolymer a-5). Obtained. The molecular properties are summarized in Table 1.

Reference Example 6
In Reference Example 1, the amount of sec-butyllithium (1.3 M cyclohexane solution) used was changed from 11.2 ml to 9.4 ml, the amount of butadiene used was changed from 323 g to 164.3 g, and dichlorodimethylsilane (0.5 M toluene solution). Was changed from 14.5 ml to 12.2 ml, and other operations were carried out in the same manner as in Reference Example 1 to obtain a block copolymer (hereinafter abbreviated as block copolymer a-6). Obtained. The molecular properties are summarized in Table 1.

Non-aromatic rubber softener (b)
(B-1): Paraffin-based process oil (trade name: Diana Process Oil PW-380, manufactured by Idemitsu Kosan Co., Ltd.)
(B-2): Paraffinic process oil (trade name: Diana Process Oil PW-90, manufactured by Idemitsu Kosan Co., Ltd.)

Ingredient (c)
(C-1): Polystyrene (trade name: GPPS679, manufactured by A & M Polystyrene, MFR = 19 g / 10 min (200 ° C., 5 kgf))
(C-2): Linear low density polyethylene (LLDPE) (trade name: Novatec LL UJ480, manufactured by Nippon Polychem, MFR = 30 g / 10 min (190 ° C., 2.16 kgf))

Example 1
The block copolymer a-1 obtained in Reference Example 1 was melt-kneaded at 230 ° C. with a twin-screw extruder, extruded into a strand, and cut to prepare pellets. The physical property evaluation results are shown in Table 2.

Comparative Example 1
The block copolymer a-4 obtained in Reference Example 4 was melt-kneaded at 230 ° C. with a twin-screw extruder, extruded into a strand, and cut to prepare pellets. The physical property evaluation results are shown in Table 2.

Examples 2-3
The block copolymer a-2 obtained in Reference Example 1 was 100 parts by mass, and the non-aromatic rubber softener b-1 was preliminarily mixed using 100 parts by mass or 50 parts by mass. Then, it melt-kneaded at 230 degreeC with the twin-screw extruder, extruded in the shape of a strand, and cut | disconnected, and prepared the pellet-shaped thermoplastic polymer composition. Table 2 shows the physical property evaluation results of the obtained thermoplastic polymer compositions.

Comparative Examples 2-3
The block copolymer a-5 obtained in Reference Example 5 was 100 parts by mass, and the non-aromatic rubber softener b-1 was preliminarily mixed using 100 parts by mass or 50 parts by mass. Then, it melt-kneaded at 230 degreeC with the twin-screw extruder, extruded in the shape of a strand, and cut | disconnected, and prepared the pellet-shaped thermoplastic resin composition. Table 2 shows the physical property evaluation results of the obtained thermoplastic polymer compositions.

Example 4
100 parts by mass of the block copolymer a-2 obtained in Reference Example 2 and 100 parts by mass of the non-aromatic rubber softener b-2 were preliminarily mixed with each other, followed by biaxial extrusion. The mixture was melt-kneaded at 230 ° C. in a machine, extruded into a strand, and cut to prepare a pellet-shaped thermoplastic polymer composition. Table 2 shows the physical property evaluation results of the obtained thermoplastic polymer composition.

Comparative Example 4
100 parts by weight of the block copolymer a-5 obtained in Reference Example 5 and 100 parts by weight of the non-aromatic rubber softener b-2 were mixed together, and then biaxially extruded. The mixture was melt-kneaded at 230 ° C. in a machine, extruded into a strand, and cut to prepare a pellet-shaped thermoplastic polymer composition. Table 2 shows the physical property evaluation results of the obtained thermoplastic polymer composition.

Examples 5-6
After 100 parts by mass of block copolymer a-1 obtained in Reference Example 1 and 10 parts by mass or 25 parts by mass of component c-1 were both premixed with a twin screw extruder. It was melt-kneaded at 230 ° C., extruded into a strand, and cut to prepare a pellet-shaped thermoplastic polymer composition. Table 3 shows the physical property evaluation results of the obtained thermoplastic polymer compositions.

Comparative Examples 5-6
After 100 parts by mass of the block copolymer a-4 obtained in Reference Example 4 and 10 parts by mass or 25 parts by mass of the component c-1 were premixed with each other, a twin screw extruder was then used. It was melt-kneaded at 230 ° C., extruded into a strand, and cut to prepare a pellet-shaped thermoplastic polymer composition. Table 3 shows the physical property evaluation results of the obtained thermoplastic polymer compositions.

Example 7
Using 100 parts by mass of the block copolymer a-2 obtained in Reference Example 2, using 120 parts by mass of the non-aromatic rubber softener b-1 and 20 parts by mass of the component c-2. These were premixed and then melt-kneaded at 230 ° C. in a twin-screw extruder, extruded into a strand, and cut to prepare a pellet-shaped thermoplastic polymer composition. Table 3 shows the physical property evaluation results of the obtained thermoplastic polymer composition.

Comparative Example 7
Using 100 parts by mass of the block copolymer a-5 obtained in Reference Example 5, using 120 parts by mass of the softening agent b-1 for non-aromatic rubber and 20 parts by mass of the component c-2. These were premixed and then melt-kneaded at 230 ° C. in a twin-screw extruder, extruded into a strand, and cut to prepare a pellet-shaped thermoplastic polymer composition. Table 3 shows the physical property evaluation results of the obtained thermoplastic polymer composition.

Example 8
Using 100 parts by mass of the block copolymer a-3 obtained in Reference Example 3, using 35 parts by mass of the non-aromatic rubber softener b-1 and 65 parts by mass of the component c-1 These were premixed and then melt kneaded at 230 ° C. in a twin screw extruder, extruded into a strand, and cut to prepare a pellet-shaped thermoplastic polymer composition. Table 3 shows the physical property evaluation results of the obtained thermoplastic polymer composition.

Comparative Example 8
Using 100 parts by mass of the block copolymer a-6 obtained in Reference Example 6, using 35 parts by mass of non-aromatic rubber softener b-1 and 65 parts by mass of component c-1 These were premixed and then melt kneaded at 230 ° C. in a twin screw extruder, extruded into a strand, and cut to prepare a pellet-shaped thermoplastic polymer composition. Table 3 shows the physical property evaluation results of the obtained thermoplastic polymer composition.

Example 9
Using 100 parts by mass of the block copolymer a-3 obtained in Reference Example 3, using 35 parts by mass of the non-aromatic rubber softener b-2 and 65 parts by mass of the component c-1 These were premixed and then melt kneaded at 230 ° C. in a twin screw extruder, extruded into a strand, and cut to prepare a pellet-shaped thermoplastic polymer composition. Table 3 shows the physical property evaluation results of the obtained thermoplastic polymer composition.

Comparative Example 9
Using 100 parts by mass of the block copolymer a-6 obtained in Reference Example 6, using 35 parts by mass of non-aromatic rubber softener b-2 and 65 parts by mass of component c-1 These were premixed and then melt kneaded at 230 ° C. in a twin screw extruder, extruded into a strand, and cut to prepare a pellet-shaped thermoplastic polymer composition. Table 3 shows the physical property evaluation results of the obtained thermoplastic polymer composition.

  From the results shown in Table 2 and Table 3, the tensile stress relaxation rate and tensile permanent elongation at 25 ° C., 40 ° C., and high temperature (70 ° C.) of the thermoplastic polymer compositions obtained in the examples of the present invention are as follows: All are small and superior to the thermoplastic polymer compositions obtained in the comparative examples. That is, the thermoplastic polymer composition of the present invention and the molded product thereof are materials having excellent stretchability even under high temperature conditions (for example, 70 ° C.).

The thermoplastic polymer composition of the present invention can be shaped into the above-described various molded articles by taking advantage of its excellent stretchability. Sanitary materials such as molded articles, paper diapers, toilet training pants, sanitary products, underwear; medical materials such as base materials for compresses, elastic tapes, bandages, surgical gowns, supporters, orthodontic gowns; hair bands, wristbands It can be used effectively for a wide range of applications such as band use such as watch bands and eyeglass bands; miscellaneous goods such as rubber bands and training tubes.

Claims (8)

(A) an α-methylstyrene block copolymer having a polymer block A mainly composed of α-methylstyrene units and a polymer block B mainly composed of conjugated diene units and having a number average molecular weight in the range of 30,000 to 500,000, and / or Alternatively, a thermoplastic polymer composition excellent in stretchability comprising 100 parts by mass of the hydrogenated product and 200 parts by mass or less of (b) a non-aromatic rubber softener. Further, (c) at least one of a polyolefin resin, a polystyrene resin, a polyphenylene ether resin, a polycarbonate resin, a polyvinyl chloride resin, a polyvinyl acetate resin, a polyester resin, and a polyamide resin is added to a block copolymer ( a) The thermoplastic polymer composition having excellent stretchability according to claim 1, which is contained at a ratio of 100 parts by mass or less with respect to 100 parts by mass. The block copolymer (a) is (1) a polymer block A mainly composed of α-methylstyrene having a number average molecular weight of 1,000 to 50,000, and (2) a number average molecular weight of 1,000 to 30,000, The amount of 1,4-bond of the conjugated diene unit constituting the block is less than 30% and the number average molecular weight is 10,000 to 400,000, and the amount of 1,4-bond of the conjugated diene unit constituting the block is 30% 3. The thermoplastic polymer composition having excellent stretchability according to claim 1, comprising a polymer block B containing the block b2 as described above and containing at least one (A-b1-b2) structure. Stuff. In the stress relaxation test described in JIS K 6263, the tensile stress relaxation rate is 30% or less when held at 40 ° C. and 50% elongation for 100 minutes, or the tensile stress relaxation rate when held at 70 ° C. and 50% elongation for 10 minutes. The thermoplastic polymer composition having excellent stretchability according to any one of claims 1 to 3, wherein the thermoplastic polymer composition is 50% or less. The elastic fiber which consists of a thermoplastic polymer composition of any one of Claims 1-4. The stretchable film which consists of a thermoplastic polymer composition of any one of Claims 1-4. The stretchable strip | belt body which consists of a thermoplastic polymer composition of any one of Claims 1-4. The elastic nonwoven fabric which consists of a thermoplastic polymer composition of any one of Claims 1-4.