Thermoplastic elastomer composition and extruded article

Abstract

The present invention relates to a thermoplastic elastomer composition comprising: (1) a component A, which is a block copolymer containing a polymer block a and a polymer block b, wherein the polymer block a contains a structural unit derived from an aromatic vinyl compound, the polymer block b contains a structural unit derived from a conjugated diene compound, and the hydrogenation rate of the polymer block b is 80% or more; (2) a component B, which is an olefin-based polymer; and (3) a hydrogenated product of a polybutene. The content of the component B is 1-50 parts by mass with respect to 100 parts by mass of the component A. The present invention provides: an extruded article that can achieve both gas barrier properties and ozone resistance; and a thermoplastic elastomer composition from which said extruded article can be obtained.

Description

Thermoplastic elastomer composition and extruded product

[0001] The present invention relates to a thermoplastic elastomer composition and further to a molded article obtained by extruding the composition, i.e., an extrusion molded article.

[0002] Conventionally, Patent Document 1 and other publications have disclosed cross-linked butyl rubber as rubber products with excellent gas barrier properties. Cross-linked rubber products are susceptible to degradation by atmospheric ozone, raising concerns that their performance may decline with long-term use. Meanwhile, Patent Document 2 discloses thermoplastic elastomers as materials with excellent gas barrier properties. While thermoplastic elastomers have excellent ozone resistance due to the absence of cross-linking components, they may experience permanent deformation if subjected to compressive or expansive (tensile) stress for extended periods. Therefore, when such thermoplastic elastomers are used in connections, concerns remain about seal leakage and other issues. Thus, even when thermoplastic elastomers are used, concerns remain about long-term reliability.

[0003] JP 2009-138076 A JP 2012-172136 A

[0004] Therefore, an object of the present invention is to provide an extrusion-molded product that can achieve both gas barrier properties and ozone resistance, and to provide a thermoplastic elastomer composition from which such an extrusion-molded product can be obtained.

[0005] The present invention relates to the following [1] to [7]. [1] Component A: a block copolymer comprising a polymer block a containing structural units derived from an aromatic vinyl compound and a polymer block b containing structural units derived from a conjugated diene compound, the weight average molecular weight being 150,000 to 500,000, the structural units derived from the aromatic vinyl compound in Component A being 10% by mass to 65% by mass, and the hydrogenation rate of the polymer block b being 80% or more, Component B: an olefin-based polymer, and Component C: a kinetic viscosity at 100°C of 100 mm ２ / s or more 3,000mm ２

[0023]

[0024] A thermoplastic elastomer composition comprising a hydrogenated polybutene having a viscosity of 1 / s or less, wherein the content of Component B is 1 part by mass or more and 50 parts by mass or less per 100 parts by mass of Component A. [2] The thermoplastic elastomer composition according to [1] above, wherein the content of Component A is 5% by mass or more and 70% by mass or less, the content of Component B is 0.5% by mass or more and 25% by mass or less, and the content of Component C is 5% by mass or more and 80% by mass or less. [3] The thermoplastic elastomer composition according to [1] or [2] above, further comprising 1 part by mass or more and 150 parts by mass or less of the following Component E per 100 parts by mass of Component A. Component E: polyphenylene ether resin. [4] The thermoplastic elastomer composition according to any one of [1] to [3] above, further comprising 10 parts by mass or more and 300 parts by mass or less of the following Component F per 100 parts by mass of Component A. Component F: Filler [5] The thermoplastic elastomer composition according to any one of [1] to [4] above, which is for extrusion molding. [6] The thermoplastic elastomer composition according to any one of [1] to [5] above, which is for use in a tube. [7] A molded article obtained by extrusion molding the thermoplastic elastomer composition according to any one of [1] to [6] above.

[0006] According to the present invention, it is possible to provide an extrusion molded article that can achieve both gas barrier properties and ozone resistance, and further according to the present invention, it is possible to provide a thermoplastic elastomer composition from which such an extrusion molded article can be obtained.

[0007] The thermoplastic elastomer composition of the present invention is a composition containing components A, B, and C as essential components.

[0008] Component A in the composition of the present invention is a block copolymer containing polymer block a and polymer block b, which will be described in detail below. Component A imparts flexibility, heat resistance, and creep resistance to the composition of the present invention. Because the composition of the present invention does not primarily contain a crosslinking component, the effect of ozone resistance, which will be described later, can also be expected.

[0009] Polymer block a contains a structural unit derived from an aromatic vinyl compound. Examples of aromatic vinyl compounds include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 1,3-dimethylstyrene, and vinylnaphthalene, and two or more of these may be used in combination. Among these, styrene is preferred because it is easily available.

[0010] Polymer block a may contain a compound other than an aromatic vinyl compound as a monomer, as long as the effect of the present invention is not impaired. Examples of such a compound include ethylene, acrylonitrile, acrylic acid esters, and vinyl acetate.

[0011] The proportion of structural units derived from aromatic vinyl compounds in all structural units constituting polymer block a is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0012] The content of structural units derived from aromatic vinyl compounds in Component A is 10% by mass or more, preferably 15% by mass or more, more preferably 20% by mass or more, from the viewpoint of creep resistance. On the other hand, from the viewpoint of flexibility, it is 65% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less. In this specification, the content of structural units derived from aromatic vinyl compounds can be measured by the method for measuring the composition of block copolymers described in the Examples.

[0013] Polymer block b contains a structural unit derived from a conjugated diene compound, such as butadiene, isoprene, isobutylene, or 1,3-pentadiene, and two or more of these may be used in combination.

[0014] The polymer block b may contain a compound other than the conjugated diene compound as a monomer, as long as the effect of the invention is not impaired. Examples of such a compound include styrene, α-olefin, and farnesene.

[0015] The proportion of the structural units derived from a conjugated diene compound among all the structural units constituting polymer block b is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. In this specification, the content of the structural units derived from a conjugated diene compound can be measured by the method for measuring the composition of a block copolymer described in the Examples.

[0016] The block copolymer of component A comprises at least one polymer block a and at least one polymer block b.

[0017] In component A, the bonding form between polymer block a and polymer block b is not particularly limited, and may be linear, branched, radial, or a combination of two or more thereof. From the viewpoint of extrusion moldability, a linear bonding form is preferred. When polymer block a is represented by "A" and polymer block b is represented by "B", the bonding form is (A-B) ｌ , A-(B-A) ｍ , B-(A-B) ｎ (wherein l, m, and n each independently represent an integer of 1 or more), and from the viewpoints of mechanical properties, extrusion moldability, etc., it is preferable that the bonding form is (A-B): ｌ , A-(B-A) ｍ , and A-(B-A) ｎ A bonding form represented by -A is more preferred, and a bonding form of a diblock structure represented by AB or a triblock structure represented by ABA is even more preferred.

[0018] Furthermore, when component A has two or more polymer blocks a or two or more polymer blocks b, the polymer blocks a and b may have the same or different structures. For example, the two polymer blocks A in the triblock structure represented by [A-B-A] may be composed of the same or different aromatic vinyl compounds.

[0019] In component A, the mass ratio of polymer block a to polymer block b (polymer block a / polymer block b) is preferably 5 / 95 to 70 / 30, more preferably 10 / 90 to 50 / 50, and even more preferably 15 / 85 to 40 / 60, from the viewpoints of flexibility, heat resistance, and creep resistance.

[0020] In the present invention, component A is preferably a hydrogenated product from the viewpoint of heat resistance, creep resistance, and ozone resistance. Hydrogenated component A (hereinafter also referred to as hydrogenated component A) is substantially a product in which some or all of the unsaturated double bonds (carbon-carbon double bonds) in polymer block b have been hydrogenated. The hydrogenation rate of polymer block b is 80% or more, preferably 85% or more, more preferably 90% or more, and even more preferably 95% or more. In the present invention, the hydrogenation rate of polymer block b can be determined by the method for measuring the hydrogenation rate described in the Examples.

[0021] The hydrogenation component A may optionally have one or more functional groups, such as a carboxy group, a hydroxy group, an acid anhydride group, an amino group, or an epoxy group, in the molecular chain and / or at the molecular terminal, within a range that does not impair the effects of the present invention.

[0022] Specific examples of hydrogenated component A include styrene-ethylene-butylene block copolymer (SEB), styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene block copolymer (SEP), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-ethylene-propylene block copolymer (SEEP), styrene-(ethylene-ethylene-propylene)-styrene block copolymer (SEEPS), (α-methylstyrene)-ethylene-butylene block copolymer, (α-methylstyrene)-ethylene-butylene-(α-methylstyrene) block copolymer, etc. These may be used alone or in a mixture of two or more types, but from the viewpoints of creep resistance and gas barrier properties, SEBS, SEPS, and SEEPS are preferred, and SEBS is more preferred. Note that, as long as the effects of the present invention are not impaired, commonly available styrene-isobutylene-styrene block copolymers (SIBS), such as the SIBSTAR series manufactured by Kaneka Corporation, may be used together with component A.

[0023] The weight-average molecular weight of component A is 150,000 or more and 500,000 or less. From the viewpoint of ensuring the moldability of hollow articles such as tubes, which is prevented by a decrease in physical properties such as strength and creep resistance and a decrease in formability during extrusion molding, the weight-average molecular weight of component A is 150,000 or more, preferably 180,000 or more, and more preferably 200,000 or more. On the other hand, from the viewpoint of preventing a decrease in the moldability of extrusion-molded articles, the weight-average molecular weight of component A is 500,000 or less, preferably 450,000 or less, and more preferably 400,000 or less. In this specification, the weight-average molecular weight (Mw) of component A can be measured by the method for measuring weight-average molecular weight described in the Examples.

[0024] The amount of 1,2-vinyl bonds derived from the conjugated diene compound in Component A is an index showing the amount of side chains in the conjugated diene polymer molecular chain. From the viewpoint of gas barrier property, the amount of 1,2-vinyl bonds in Component A is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, in the conjugated diene compound. On the other hand, from the viewpoint of creep resistance and ozone resistance, the amount of 1,2-vinyl bonds is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less, in the conjugated diene compound. In this specification, the amount of 1,2-vinyl bonds can be measured by the method for measuring the content of 1,2-vinyl bond units in polymer block b described in the Examples.

[0025] From the viewpoint of imparting flexibility and heat resistance to the composition, the content of component A in the composition of the present invention is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, and on the other hand, is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less.

[0026] Component A can be produced by a conventionally known method. Component A is available as a commercially available product. Examples of commercially available products include the Kraton G series, Kraton FG series, Kraton MD series, and Kraton A series manufactured by Kraton Polymers, the Tuftec series and S.O.E. series manufactured by Asahi Kasei Corporation, and the Septon series and Hybler series manufactured by Kuraray Co., Ltd.

[0027] Component B in the composition of the present invention is an olefin polymer. Component B has excellent miscibility with component A, applies strong shear force (kneading force) to component A in the early stages of melt production of the composition of the present invention, and has the effect of reducing the viscosity of component A as the mixing progresses, thereby promoting the dispersion of component A and reducing the occurrence of lumps due to poor kneading. Furthermore, the mixing of component B with component A improves the strength, heat resistance, and moldability of the composition.

[0028] Examples of olefin polymers that can be used as component B include known polymers such as polyethylene, polypropylene, ethylene-propylene copolymers, and α-olefin copolymers. Among these, polypropylene and ethylene-propylene copolymers are preferred from the viewpoints of heat resistance and miscibility. Polypropylene is more preferred from the viewpoint of heat resistance.

[0029] The melting point of component B is preferably 100°C or higher from the viewpoint of heat resistance, and preferably 200°C or lower from the viewpoint of moldability. From these viewpoints, the melting point of component B is more preferably in the range of 120 to 190°C, even more preferably 140 to 185°C, and even more preferably 150 to 180°C. In this specification, the melting point can be measured by the melting point measurement method described in the Examples.

[0030] The melt mass-flow rate of Component B at 230°C and 21N is preferably 0.1 g / 10 min or more from the viewpoint of moldability, and preferably 100 g / 10 min or less from the viewpoint of moldability. From these viewpoints, the range of the melt mass-flow rate of Component B at 230°C and 21N is preferably 0.1 to 100 g / 10 min, more preferably 0.5 to 80 g / 10 min, and even more preferably 1.0 to 50 g / 10 min. In this specification, the melt mass-flow rate can be measured by the melt mass-flow rate measurement method described in the Examples.

[0031] The flexural modulus of component B is preferably 30 MPa or more from the viewpoint of heat resistance, and preferably 2,500 MPa or less from the viewpoint of flexibility. From these viewpoints, the flexural modulus of component B is more preferably in the range of 50 to 2,000 MPa, even more preferably 100 to 1,850 MPa, and even more preferably 200 to 1,700 MPa. In this specification, the flexural modulus can be measured by the flexural modulus measurement method described in the Examples.

[0032] The ratio of Component A to Component B in the composition of the present invention is, from the viewpoints of kneadability with Component A and extrusion moldability, 1 part by mass or more, preferably 3 parts by mass or more, and more preferably 5 parts by mass or more of Component B per 100 parts by mass of Component A. On the other hand, from the viewpoint of maintaining the flexibility of the composition of the present invention, 50 parts by mass or less, preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less of Component B per 100 parts by mass of Component A.

[0033] The content of component B in the composition of the present invention is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 1.5% by mass or more, from the viewpoint of kneadability with component A and extrusion moldability, while from the viewpoint of maintaining the flexibility of the composition of the present invention, it is preferably 25% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less.

[0034] Component B can be produced by a conventionally known method. Component B is available as a commercially available product. Examples of commercially available products include the PM series manufactured by SunAllomer Co., Ltd., the Novatec PP series manufactured by Japan Polypropylene Corporation, and the Prime Polypropylene series manufactured by Prime Polymer Co., Ltd.

[0035] Component C in the composition of the present invention is a hydrogenated polybutene. The polybutene of component C of the present invention is also widely known as polyisobutylene. The use of such component C is preferred because it not only improves flexibility, moldability, gas barrier properties, and permanent set of the composition of the present invention, but also imparts ozone resistance. From the viewpoint of improving gas barrier properties, the number average molecular weight of component C is preferably 800 or more, more preferably 850 or more, and even more preferably 900 or more. On the other hand, from the viewpoints of miscibility with component A and creep resistance, the number average molecular weight of component C is preferably 2,500 or less, more preferably 2,000 or less, and even more preferably 1,500 or less. In this specification, the number average molecular weight can be measured by the method for measuring number average molecular weight described in the examples.

[0036] The kinematic viscosity of component C at 100°C is 100 mm ２ / s or more, 3,000mm ２From the viewpoint of improving the gas barrier property, it is preferably 150 mm ２ / s or more, more preferably 200 mm ２ On the other hand, from the viewpoint of miscibility with component A and creep resistance, the kinematic viscosity of component C is preferably 2,000 mm ２ / s or less, more preferably 1,000 mm ２ / s or less, more preferably 600 mm ２ In this specification, the kinematic viscosity can be measured by the kinematic viscosity measurement method described in the examples.

[0037] Ozone in the atmosphere tends to cause the unsaturated bonds in component C to undergo lower molecular weight, which can result in cracking on the surface of molded articles of the composition of the present invention, deterioration in creep resistance, increased bleeding, and reduced performance such as stickiness. Polybutene is produced by so-called cationic polymerization using butene and isobutene as the main raw materials and a Lewis acid such as boron trifluoride or aluminum chloride and an initiator such as water as a catalyst. After production, a small amount of unsaturated double bonds remains in the polybutene molecular chain. The remaining unsaturated double bonds are radicalized by ozone in the atmosphere, scission of the polybutene molecular chain, and the formation of low-molecular-weight components. The generated low-molecular-weight components bleed to the surface of thermoplastic elastomer molded articles, causing problems such as stickiness. Therefore, a hydrogenated polybutene is preferred as component C.

[0038] From the viewpoint of suppressing such a decrease in performance, hydrogenated polybutene is more preferred as component C. The hydrogenation rate in the hydrogenated polybutene is preferably 80% or more, more preferably 90% or more, even more preferably 99% or more, and still more preferably 99.8% or more. In this specification, the hydrogenation rate in the hydrogenated polybutene can be measured by the method for measuring the hydrogenation rate described in the Examples.

[0039] The ratio of Component A to Component C in the composition of the present invention, from the viewpoints of maintaining the flexibility of the composition of the present invention and imparting gas barrier properties, is preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and even more preferably 50 parts by mass or more, of Component C per 100 parts by mass of Component A. On the other hand, from the viewpoint of suppressing stickiness on the surface of a molded article of the composition of the present invention, the ratio of Component C per 100 parts by mass of Component A is preferably 400 parts by mass or less, more preferably 300 parts by mass or less, even more preferably 250 parts by mass or less, and even more preferably 200 parts by mass or less.

[0040] The content of component C in the composition of the present invention is preferably 5% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, from the viewpoint of flexibility and gas barrier properties of the composition of the present invention, while it is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less, from the viewpoint of suppressing stickiness on the surface of a molded article of the composition of the present invention.

[0041] Component C can be produced by a conventionally known method. Component C is available as a commercially available product. Examples of commercially available products include the Nippon Oil Polybutene HV series manufactured by ENEOS Corporation, the Palmream series manufactured by NOF Corporation, and the Indopol series and Panalane series manufactured by INEOS Corporation.

[0042] Furthermore, paraffin oil or the like may be added as a softener together with component C of the present invention, provided that the effects of the present invention are not impaired. Commonly available paraffin oils include the Diana Process Oil series manufactured by Idemitsu Kosan Co., Ltd., the Lucant series manufactured by Mitsui Chemicals, Inc., and the VIVA-B-FIX series manufactured by H&R.

[0043] From the viewpoint of improving bleeding properties, the number average molecular weight of such paraffin oil is preferably 300 or more, more preferably 500 or more, and even more preferably 700 or more. On the other hand, from the viewpoint of miscibility with Component A and creep resistance, the number average molecular weight of Component C is preferably 2,500 or less, more preferably 2,000 or less, and even more preferably 1,500 or less. In this specification, the number average molecular weight can be measured by the method for measuring number average molecular weight described in the Examples.

[0044] The kinematic viscosity of such paraffin oil at 40°C is preferably 30 mmHg or less from the viewpoint of bleeding property to component A. ２ / s or more, more preferably 80 mm ２ / s or more, more preferably 150 mm ２ On the other hand, from the viewpoint of miscibility with component A, it is preferably 1,000 mm ２ / s or less, more preferably 800 mm ２ / s or less, more preferably 500 mm ２ In this specification, the kinematic viscosity can be measured by the kinematic viscosity measurement method described in the examples.

[0045] The hydrogenated polybutene used as component C in the present invention can be used in combination with a softener other than component C, such as paraffin oil, and the weight ratio of hydrogenated polybutene to paraffin oil used is preferably in the range of 1 / 99 to 99 / 1. From the viewpoint of gas barrier property, the lower limit of the hydrogenated polybutene is more preferably 10 / 90 or more, even more preferably 15 / 85 or more, and even more preferably 20 / 80 or more. On the other hand, from the viewpoint of compression set, the upper limit of the hydrogenated polybutene is more preferably 90 / 10 or less, even more preferably 85 / 15 or less, and even more preferably 80 / 20 or less.

[0046] Component D in the composition of the present invention is an acrylic polymer containing structural units derived from a (meth)acrylic acid ester and having a weight-average molecular weight of 400,000 or more. Component D is a polar polymer and therefore has high molecular cohesion, and due to its high molecular weight, when the composition of the present invention contains Component D, it has the effect of increasing the melt viscosity and melt tension of the composition of the present invention during melt-kneading or extrusion molding.

[0047] As a result, it is expected that the extrusion moldability will be improved by grinding up poorly dispersed particles resulting from insufficient kneading of component A, which is one of the causes of surface roughness in molded articles obtained using the composition of the present invention. In addition, it adjusts the melt viscosity and melt tension of the composition of the present invention during extrusion molding, imparts shapeability during extrusion molding, and improves extrusion moldability. Furthermore, it is presumed that it is immiscible with component A at room temperature and forms a unique dispersed phase in the molded article, and as a result, the acrylic molecules with high cohesive strength are expected to have the effect of improving the creep resistance of the composition of the present invention.

[0048] Component D is not particularly limited as long as it is an acrylic polymer containing a structural unit derived from a (meth)acrylic acid ester, but a polymer containing a structural unit derived from methyl methacrylate is preferred, a methacrylic acid ester-acrylic acid ester copolymer is preferred, and an alkyl methacrylate-alkyl acrylate copolymer is more preferred.

[0049] Here, "(meth)acrylic" means acrylic and / or methacrylic. "(meth)acrylic acid ester" means acrylic acid ester and / or methacrylic acid ester. Furthermore, "alkyl acrylate" and "alkyl methacrylate" mean alkyl esters of acrylic acid and alkyl esters of methacrylic acid, respectively.

[0050] The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms. Examples of alkyl (meth)acrylates having an alkyl group having 1 to 4 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate, and from the viewpoint of increasing the melt viscosity, methyl methacrylate (MMA) is preferred as the methacrylic acid ester, and from the viewpoint of affinity with Component A of the present invention, normal butyl acrylate (n-BA), isobutyl acrylate (i-BA), and 2-ethylhexyl acrylate (HA) are preferred as the acrylic acid ester.

[0051] From the viewpoints of extrusion moldability and creep resistance, the alkyl methacrylate-alkyl acrylate copolymer is preferably a copolymer of alkyl methacrylate and n-butyl acrylate, and more preferably a copolymer of methyl methacrylate and n-butyl acrylate. Here, the proportions of alkyl methacrylate and alkyl acrylate are preferably 95 to 55% by mass and 45 to 10% by mass, respectively, more preferably 90 to 60% by mass and 40 to 10% by mass, respectively, and even more preferably 88 to 80% by mass and 12 to 20% by mass, respectively. Random copolymers in which methyl methacrylate and n-butyl acrylate are randomly bonded, and block copolymers having block polymerization units in which n-butyl acrylate is repeatedly bonded, are more preferred. Considering the copolymerizability of alkyl methacrylate and n-butyl acrylate, a small amount of n-butyl acrylate blocks will naturally be formed, and the presence of such blocks in the alkyl methacrylate-alkyl acrylate copolymer is acceptable. In this specification, the ratio of alkyl methacrylate to alkyl acrylate can be measured by the pyrolysis gas chromatography / mass spectrometry measurement method described in the Examples.

[0052] Component D may further contain at least one other vinyl monomer copolymerizable with the (meth)acrylic acid ester as a constituent unit. Here, from the viewpoint of creep resistance, the proportion of the (meth)acrylic acid ester is preferably 70% by mass or more, more preferably 90% by mass or more, and even more preferably 100% by mass, while the proportion of the "other vinyl monomer" is preferably 30% by mass or less, more preferably 10% by mass or less, and even more preferably 0% by mass.

[0053] The molecular structure of component D may be any of a linear structure, a branched structure, and a graft structure grafted onto a crosslinked rubber, i.e., a so-called core-shell rubber, but from the viewpoints of increasing the melt viscosity, improving the extrusion moldability, and preventing the generation of lumps due to the crosslinked component, a non-crosslinked linear structure or a branched structure is preferred, and from the viewpoint of increasing the melt viscosity, a linear structure is more preferred.

[0054] From the viewpoint of creep resistance, the weight average molecular weight of component D is 400,000 or more, preferably 700,000 or more, and more preferably 1,000,000 or more. From the viewpoint of extrusion moldability, the weight average molecular weight is preferably 7,000,000 or less, more preferably 6,000,000 or less, and even more preferably 5,000,000 or less. In this specification, the weight average molecular weight can be measured by the method for measuring weight average molecular weight described in the Examples.

[0055] When the composition of the present invention contains Component D, the ratio of Component A to Component D in the composition of the present invention is, from the viewpoint of improving the extrusion moldability and creep resistance of the composition of the present invention, preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 4 parts by mass or more of Component D per 100 parts by mass of Component A. On the other hand, from the viewpoint of maintaining the flexibility of the composition of the present invention, preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less of Component D per 100 parts by mass of Component A.

[0056] When the composition of the present invention contains Component D, the content of Component D in the composition of the present invention is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more, from the viewpoint of improving the extrusion moldability and creep resistance of the composition of the present invention, while it is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less, from the viewpoint of maintaining the flexibility of the composition of the present invention.

[0057] Component D can be produced by a conventionally known method. Component D is available as a commercially available product. Examples of commercially available products include those known as acrylic processing aids, such as Mitsubishi Chemical's "Metablen P Series," Dow Chemical's "Paraloid K Series," and Kaneka's "Kane Ace PA Series."

[0058] Component E in the composition of the present invention is a polyphenylene ether resin. Component E is miscible with polymer block a containing structural units derived from an aromatic vinyl compound of Component A and has the effect of increasing the glass transition temperature of the styrene phase. As a result, the heat resistance and creep resistance of the composition of the present invention can be expected to be improved. Therefore, it is preferable that the composition of the present invention contains Component E.

[0059] Specific examples of component E include homopolymers such as poly(2,6-dimethyl-1,4-phenylene ether), poly(2-methyl-6-ethyl-1,4-phenylene ether), poly(2-methyl-6-phenyl-1,4-phenylene ether), and poly(2,6-dichloro-1,4-phenylene ether), as well as polyphenylene ether copolymers such as copolymers of 2,6-dimethylphenol with other phenols (for example, copolymers with 2,3,6-trimethylphenol and copolymers with 2-methyl-6-butylphenol as described in JP-B No. 52-17880). Furthermore, the polyphenylene ether resin may be a modified polyphenylene ether resin in which all or part of the polyphenylene ether resin has been modified.

[0060] From the viewpoint of miscibility, the reduced viscosity of Component E is preferably 0.1 dL / g or more, and from the viewpoint of dispersibility and the surface properties of the molded product, it is preferably 0.45 dL / g or less. From these viewpoints, the reduced viscosity of Component E is preferably 0.1 dL / g to 0.45 dL / g, more preferably 0.15 dL / g to 0.45 dL / g, and even more preferably 0.2 dL / g to 0.45 dL / g. In this specification, the reduced viscosity can be measured by the reduced viscosity measurement method described in the Examples.

[0061] From the viewpoint of resistance to compression set, the glass transition temperature of Component E is preferably 170° C. or higher, and from the viewpoint of thermal degradation during production of the composition, it is preferably 260° C. or lower. From these viewpoints, the glass transition temperature of Component E is preferably 170 to 260° C., more preferably 180 to 250° C., and even more preferably 190 to 240° C. In this specification, the glass transition temperature can be measured by the method for measuring glass transition temperature described in the examples.

[0062] When the composition of the present invention contains Component E, the ratio of Component A to Component E is, from the viewpoint of improving the compression set resistance of the composition of the present invention, preferably 1 part by mass or more, more preferably 10 parts by mass or more, and even more preferably 20 parts by mass or more of Component E per 100 parts by mass of Component A. On the other hand, from the viewpoint of flexibility, the ratio of Component E per 100 parts by mass of Component A is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 70 parts by mass or less.

[0063] When the composition of the present invention contains Component E, the content of Component E in the composition of the present invention is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, from the viewpoint of improving the compression set resistance of the composition of the present invention, while from the viewpoint of flexibility, it is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less.

[0064] Component E can be produced by a conventionally known method. Component E is available as a commercially available product. Examples of commercially available products include the Zylon series manufactured by Asahi Kasei Corporation, the Noryl series manufactured by SABIC Corporation, the Iupiace series and Lemalloy series manufactured by Global Polyacetal Corporation, and the Bestran series manufactured by Polypla-Evonik.

[0065] The filler of component F is expected to have the effect of improving the gas barrier properties of the composition of the present invention. Therefore, the composition of the present invention preferably contains component F.

[0066] Preferred materials for component F include inorganic fillers such as talc, calcium carbonate, mica, kaolin, wollastonite, ferrite, clay, glass flakes, titanium oxide, silica, and alumina.

[0067] From the viewpoint of gas barrier properties, the shape of component F is preferably one in which the plate surface is large relative to the particle size, for example, a plate-like or scaly filler. More specifically, from the viewpoint of gas barrier properties, the aspect ratio of component F, expressed as the major axis / thickness, is preferably 1.1 or more, more preferably 1.2 or more. From the viewpoint of compression set resistance, it is 50 or less, more preferably 40 or less. In this specification, the aspect ratio can be measured by the aspect ratio measurement method described in the examples.

[0068] From the viewpoints of extrusion moldability and gas barrier properties, the particle size of component F is preferably 150 μm or less, more preferably 50 μm or less, and even more preferably 20 μm or less, in terms of volume-based median diameter, and is preferably 0.1 μm or more, more preferably 1 μm or more, and even more preferably 10 μm or more. In this specification, the volume-based median diameter can be measured by the method for measuring volume-based median diameter described in the Examples.

[0069] When the composition of the present invention contains Component F, the ratio of Component A to Component F, from the viewpoint of gas barrier property, is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 40 parts by mass or more, of Component F per 100 parts by mass of Component A. On the other hand, from the viewpoint of flexibility, the ratio of Component F per 100 parts by mass of Component A is preferably 300 parts by mass or less, more preferably 250 parts by mass or less, and even more preferably 200 parts by mass or less.

[0070] When the composition of the present invention contains component F, the content of component F in the composition of the present invention is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, from the viewpoint of gas barrier property, while it is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less, from the viewpoint of flexibility.

[0071] Component F can be produced by a conventionally known method. Component F is available as a commercially available product. Examples of commercially available products include the fine powder talc series and general-purpose talc series manufactured by Nippon Talc Co., Ltd., and the P-talc and Hitron series manufactured by Takehara Chemical Industry Co., Ltd.

[0072] The composition of the present invention may contain various additives, as needed, within the range that does not impair the effects of the present invention, such as organic fillers (e.g., wood flour, cellulose powder, and organic fibers), antioxidants (e.g., phenolic, sulfur-based, and phosphorus-based), softeners other than Component C of the present invention, weather resistance stabilizers, ultraviolet absorbers (e.g., benzotriazole-based, tridiamine-based, anilide-based, and benzophenone-based), heat stabilizers, antioxidants, light stabilizers (e.g., hindered amine-based and benzoate-based), antistatic agents, nucleating agents, pigments, adsorbents (e.g., metal oxides), metal chlorides (e.g., iron chloride and calcium chloride), hydrotalcite, aluminates, lubricants (e.g., fatty acids, higher alcohols, aliphatic amides, and aliphatic esters), flame retardants, foaming agents, and silicone compounds.

[0073]

[0033] From the viewpoint of adjusting the flexibility, gas barrier property, creep resistance, and extrusion moldability aimed at by the present invention, the total amount of Component A, Component B, and Component C in the thermoplastic elastomer composition of the present invention is preferably 20% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more. The upper limit of the total amount is 100% by mass, but is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less.

[0074] The thermoplastic elastomer composition of the present invention can be obtained by mixing raw materials including component A, component B, component C, and, if necessary, component D, component E and / or component F, and various additives, and solidifying the mixture by cooling.

[0075] The term "mixing" as used herein is not particularly limited as long as it is a method by which the various components can be mixed well. The various components may be mixed by dissolving them in an organic solvent in which they can be dissolved, or by heating and melt-kneading. However, it is preferable that the raw materials be mixed under conditions in which the raw materials other than component F are melted.

[0076] In the case of heat-melt kneading, a general extruder can be used, and it is preferable to use a multi-screw extruder having two or more screws to improve the kneading state. The components may be mixed in advance using a mixing device such as a Henschel mixer and then fed to the extruder from one hopper, or the components may be charged into two hoppers and fed in measured amounts using screws or the like below the hoppers.

[0077] The product obtained by mixing the raw materials constituting the thermoplastic elastomer composition can be formed into pellets, sheets, etc. depending on the application. For example, the product is heated, melted, kneaded, and extruded into strands using an extruder, and then cooled in cold water and cut into cylindrical, rice-grain-shaped, or other pellets using a cutter.

[0078] The thermoplastic elastomer composition of the present invention can be formed into a thermoplastic elastomer molded article by various known molding methods, such as extrusion molding, press molding, injection molding, calendar molding, blow molding, and foam molding. Therefore, one of the preferred uses of the thermoplastic elastomer composition of the present invention is, of course, injection molding, in which the mold surface is transferred, but also extrusion molding, because the extrusion molded article has excellent extrusion moldability even without mold surface transfer. Furthermore, molded articles such as sheets or pellets can also be further processed by thermoforming or the like.

[0079] The thermoplastic elastomer composition of the present invention has an A hardness, as measured in accordance with JIS K 6253, of preferably 10 points or more, more preferably 20 points or more, and even more preferably 30 points or more, from the viewpoint of heat resistance, and preferably 90 points or less, more preferably 70 points or less, and even more preferably 60 points or less, from the viewpoint of flexibility.

[0080] The melt mass-flow rate of the thermoplastic elastomer composition of the present invention at 230°C under a load of 49 N according to JIS K 7210-1 is preferably 0.05 g / 10 min or more, more preferably 0.1 g / 10 min or more, and even more preferably 0.2 g / 10 min or more, from the viewpoint of extrusion productivity. From the viewpoint of extrusion moldability and shapeability, it is preferably 50 g / 10 min or less, more preferably 20 g / 10 min or less, and even more preferably 15 g / 10 min or less.

[0081] The thermoplastic elastomer composition of the present invention can be used to obtain molded articles having resistance to compressive (also known as compression set) or dilatational (tensile) stress (also known as tensile set), i.e., creep resistance, and in particular, can obtain molded articles having creep resistance at high temperatures, for example, at 70°C. Therefore, the thermoplastic elastomer composition of the present invention is particularly suitable for use in tube parts that require flexibility for transporting liquids that may be exposed to high temperatures. Furthermore, molded articles having even longer-term creep resistance can be obtained, not only at high temperatures but also at temperatures around room temperature.

[0082] The performance evaluation items required for such a liquid transport tube include permanent deformation (creep resistance), extrusion moldability with excellent smoothness, gas barrier properties, ozone resistance, and the like.

[0083] Permanent set (creep resistance) refers to durability against long-term compression and expansion (tensile) stress, and is the resistance to compressive strain such that when the tube is crushed with a clip or the like to stop the liquid flow, the liquid flow path can be immediately released when the clip is removed. It is more preferable that the tube has tensile creep resistance that will not rupture over the long term when inserted into a connection port with a diameter larger than the inner diameter of the tube.

[0084] The term "extrusion moldability with excellent smoothness" refers to a surface property that allows bubbles to grow from minute irregularities on the inner surface of the tube, preventing liquid blockage. In particular, if the tube is not used for a long period of time, gas may accumulate inside the tube, causing blockage of the liquid inside, so it is preferable that the surface of the molded product is smoother.

[0085] Gas barrier performance is even more important for tubes, which have a larger surface area per inner diameter than hoses, and is required to prevent oxidation and deterioration of the liquid components contained in the tubes and liquid blockage due to bubbles.

[0086] Ozone resistance refers to the long-term stability of physical properties against deterioration due to atmospheric ozone, and also to the effect of preventing deterioration in the quality of the content liquid due to the elution of low-molecular-weight components generated by ozone oxidation into the content liquid.

[0087] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Various physical properties of the raw materials used in the examples were measured by the following methods.

[0088] <Component A: Block Copolymer> [Weight Average Molecular Weight (Mw)] The weight average molecular weight (Mw) was determined as a polystyrene-equivalent weight average molecular weight by gel permeation chromatography under the following measurement conditions. Measurement equipment Pump: PU-980 manufactured by JASCO (Japan Spectroscopic Corporation) Column oven: AO-50 manufactured by Showa Denko K.K. Detector: RI (differential refractometer) detector, L-3300 manufactured by Hitachi Column type: One each of "K-805L (8.0 x 300 mm)" and "K-804L (8.0 x 300 mm)" manufactured by Showa Denko K.K. used in series Column temperature: 40°C Guard column: K-G (4.6 x 10 mm) Eluent: chloroform Eluent flow rate: 1.0 mL / min Sample concentration: approximately 1 mg / mL Sample solution filtration: polytetrafluoroethylene 0.45 μm pore size disposable filter Standard sample for calibration curve: polystyrene manufactured by Showa Denko K.K.

[0089] [Composition of Block Copolymer] Proton NMR measurement was performed using a nuclear magnetic resonance apparatus (DPX-400, manufactured by BRUKER, Germany) to determine the content of structural units derived from styrene and / or styrene derivatives, for example, by quantifying the characteristic groups of styrene. The content of other monomer units, such as structural units derived from aromatic vinyl compounds and conjugated diene compounds, can also be determined by proton NMR measurement.

[0090] [Content of 1,2-vinyl bond units in polymer block b] The block copolymer before hydrogenation was dissolved in CDCl ３ The resulting solution was dissolved in 1,2-vinyl bond units and the proton NMR spectrum was measured (apparatus: JNM-Lambda 500 (manufactured by JEOL Ltd.), measurement temperature: 50°C). The content of 1,2-vinyl bond units was calculated from the ratio of the total peak area of ​​the conjugated diene compound units to the peak area corresponding to the 1,2-vinyl bond units in the conjugated diene compound units.

[0091] [Hydrogenation Rate] The hydrogenation rate of polymer block b was determined by measuring the content of carbon-carbon double bonds derived from the conjugated diene compound in the block copolymer by proton NMR spectroscopy before and after hydrogenation, and then determining the hydrogenation rate from the measured value.

[0092] <Component B: Olefin Polymer> [Melt Mass Flow Rate (MFR)] Measured at 230° C. and a load of 21 N according to a method in accordance with JIS K6921-2.

[0093] [Flexural Modulus] A test piece having a length of 80 mm, a width of 10 mm and a thickness of 4 mm was subjected to a three-point bending test at a speed of 2 mm / min according to a method in accordance with JIS K7171.

[0094] [Melting Point] The melting point was measured in accordance with ISO 11357-3 using a differential scanning calorimeter in a nitrogen atmosphere at a temperature rise rate of 10°C / min, as the melting peak temperature.

[0095] <Component C: Hydrogenated Polybutene> [Kinematic Viscosity] Kinematic viscosity was measured at temperatures of 100°C and 40°C using a Brookfield rotational viscometer in accordance with JIS K 7117-1.

[0096] [Hydrogenation Ratio] The hydrogenation ratio of a hydrogenated polybutene was determined by the area ratio of the signal intensities of a signal due to saturated carbon bonds to a signal due to unsaturated carbon bonds when the polybutene was measured by proton NMR. Hereinafter, this ratio will also be referred to as saturated / unsaturated signals.

[0097] [Weight-average molecular weight (Mw), number-average molecular weight (Mn)] The weight-average molecular weight was determined in the same manner as for the block copolymer of Component A. The number-average molecular weight was also determined in polystyrene equivalent terms in the same manner as for Component A.

[0098] <Component D: Acrylic Polymer> [Weight-Average Molecular Weight (Mw)] The weight-average molecular weight (Mw) was determined in the same manner as for the block copolymer of component A.

[0099] [MMA / n-BA ratio] The MMA / n-BA ratio was determined as follows. It was identified by mass obtained by pyrolysis gas chromatography / mass spectrometry (GC / MS) and quantified by the detected peak ratio. Mass spectrometer: JMS-T100GC manufactured by JEOL Ltd. Pyrolyzer: PY2020D manufactured by Frontier Labs Gas chromatograph: Agilent 6890N manufactured by Agilent Technologies Column: DB-SMS Gas flow rate: 1.0 ml / min Pyrolysis temperature: 550°C

[0100] <Polyphenylene Ether Resin of Component E> [Reduced Viscosity] The reduced viscosity of Component E was determined by the method according to JIS K 7367, and was determined as the viscosity at 30° C. of a solution obtained by dissolving Component E in chloroform at a concentration of 0.5 g / dL.

[0101] [Glass Transition Temperature] The glass transition temperature of component E was measured in accordance with ISO 11357-2 using a differential scanning calorimeter in a nitrogen atmosphere at a temperature rise rate of 10°C / min, measuring the midpoint temperature.

[0102] <Filler of Component F> [Aspect Ratio: Length / Thickness Ratio] The aspect ratio of the filler was determined using a scanning electron microscope as follows. A Hitachi High-Tech Fielding SU1510 scanning electron microscope was used. [Sample Preparation] Conductive carbon double-sided tape was attached to an aluminum electron microscope stage, and the target filler powder was thinly spread on the tape. The excess filler powder was then removed with an air blower. [Measurement] The sample stage was placed in an electron microscope, and an appropriate number of enlarged photographs were taken at different magnifications and positions at an accelerating voltage of 10 kV depending on the particle diameter and aspect ratio (length and thickness) of each filler sample. Thirty particles were randomly selected from the unagglomerated particles observed in the photographs, and their individual lengths and thicknesses were measured using image analysis and measurement software ("WinRooF2015" manufactured by Mitani Shoji Co., Ltd.) to determine the average values.

[0103] [Volume Median Diameter] The volume median diameter (D50) of the filler of component F was determined as follows: In accordance with the laser diffraction / scattering method specified in JIS Z 8825, 0.1 g of a sample was dispersed in 10 mL of deionized water and ultrasonically dispersed at 70 W for 30 seconds. The particle size distribution of the resulting slurry was measured using a Mastersizer 2000 manufactured by Malvern Instruments, and the 50% value in the volume-based cumulative fraction was taken as the volume median diameter.

[0104] <Thermoplastic elastomer composition> [A hardness] Three 2 mm thick sheets were stacked (total thickness: 6 mm), and the A hardness was measured using a Type A durometer in accordance with JIS K 6253. The A hardness was measured at a measurement time of 1 second (value 1 second after the start of the test). The measurement was carried out after conditioning for 1 day indoors at a temperature of 23°C and humidity of 50%.

[0105] [Melt Mass Flow Rate (MFR)] Measured in accordance with JIS K 7210-1 under test conditions of 230° C. and a load of 49 N.

[0106] Examples 1 to 12, Comparative Examples 1 to 3, and Reference Example 1 (1) Preparation of Thermoplastic Elastomer Composition (Pellets) The components shown in Tables 1 to 4 and 100 parts by mass of component A were all charged into a Kawata Supermixer SMV-20Ba, and the resulting raw material powder was heated and mixed at 60 to 80°C. The resulting raw material powder was fed from the raw material feed hopper to an extruder and melt-kneaded under the following conditions: The strand-shaped resin discharged from the extruder was cooled in cold water and cut into pellets with a diameter of about 3 mm and a thickness of about 3 mm using a cutter.

[0107] <Melt-kneading conditions> Extruder: Shibaura Machine Co., Ltd., twin-screw kneading extruder, TEM-26SX-16 / 1V Cylinder temperature: The temperature conditions near the hopper were set to 180°C, and up to the extruder outlet to 240°C Screw rotation speed: 400 r / min Extrusion die: 3 mm diameter strand die Raw material supply rate: 15 kg / h

[0108] (2) Preparation of 2 mm thick sheet The pellets were injection molded under the following conditions to prepare a sheet having a width of 125 mm, a length of 125 mm, and a thickness of 2 mm.

[0109] <Injection molding conditions> Injection molding machine: 100MSIII-10E (product name, manufactured by Mitsubishi Heavy Industries, Ltd.) Injection molding temperature: 200°C Injection pressure: 30% Injection time: 10 seconds Mold temperature: 40°C

[0110] Details of typical components used in the Examples, Comparative Examples, and Reference Examples are summarized below.

[0111] Component A-1: ​​Styrene-ethylene butylene-styrene block copolymer (SEBS) (Kraton Corporation, Kraton G1651, weight average molecular weight (Mw): 290,000, styrene content: 33 mass%, 1,2-vinyl bond content: 37 mass%, hydrogenation rate of polymer block b: 99.6%) Component A-2: Styrene-ethylene butylene-styrene block copolymer (SEBS) (Kraton Corporation, Kraton G1641, weight average molecular weight (Mw): 240,000, styrene content: 33 mass%, 1,2-vinyl bond content: 67 mass%, hydrogenation rate of polymer block b: 99.6%) Component A-3: Styrene-isobutylene-styrene block copolymer (SIBS) (Kaneka Corporation, SIBSTAR 103T-UC, weight average molecular weight (Mw): 120,000, styrene content: 30 mass%) Component A-3 does not fall under Component A, but is a comparative component for Component A.

[0112] Component B: Homopolypropylene (manufactured by SunAllomer Co., Ltd., PM600A, MFR at 230°C and 21N: 7.5 g / 10 min, melting point: 163°C, flexural modulus: 1,680 MPa)

[0113] Component C-1: Hydrogenated polybutene (NOF Corporation, Parleam 18, kinematic viscosity at 100°C: 300 mm ２ / s, kinematic viscosity at 40 ° C: 10,500 mm ２ / s, saturated / unsaturated signal: 99.99 / 0.01, weight average molecular weight: 1,940, number average molecular weight: 1,000) Component C-2: non-hydrogenated polybutene (ENEOS Corporation, HV-300, kinematic viscosity at 100°C: 590 mm ２ / s, kinematic viscosity at 40 ° C: 26,000 mm ２ / s, saturated / unsaturated signal: 99.65 / 0.35, weight average molecular weight: 3,107, number average molecular weight: 1,400) Component C-3: non-hydrogenated polybutene (ENEOS Corporation, HV-100, kinematic viscosity at 100°C: 220 mm ２ / s, kinematic viscosity at 40 ° C: 9,500 mm ２ / s, saturated / unsaturated signal: 99.47 / 0.53, weight average molecular weight: 1,901, number average molecular weight: 980) Component C-4: Paraffin oil (Idemitsu Kosan Co., Ltd., PW-380, kinematic viscosity at 100°C: 31 mm ２ / s, kinematic viscosity at 40 ° C: 408 mm ２ / s, saturated / unsaturated signal: (none), weight average molecular weight: 1,263, number average molecular weight: 1,128) Components C-2 to C-4 do not correspond to component C, but are components for comparison with component C.

[0114] Component E: Polyphenylene ether (PPE) (manufactured by Asahi Kasei Chemicals Corporation, Zylon S202A, reduced viscosity: 0.42 dL / g, Tg: 214°C) Component F: Talc (manufactured by Hayashi Chemical Co., Ltd., TP-TK, volume-based median diameter (D50): 13 μm, aspect ratio: 33, shape: plate-like)

[0115] The thermoplastic elastomer compositions obtained in the Examples, Comparative Examples, and Reference Examples were evaluated as follows. The results are shown in Tables 1 to 4.

[0116] [Oxygen Permeability Coefficient] A 2 mm thick sheet was cut into a piece 25 mm wide x 30 mm long, and a 0.5 mm thick x 100 mm wide x 120 mm long press mold was used. The piece was hot-pressed for 2 minutes using a hot press machine (Toho Machinery Co., Ltd., hydraulic molding machine TB-50-2) heated to 160°C, and then cooled and pressed for 3 minutes to produce a 0.5 mm thick press-molded sheet as a test piece. The test piece dimensions were 90 mm x 90 mm x 0.5 mm, and the permeation area was 38.5 cm. ２ The gas permeability was measured at 23° C. using a gas permeability measuring device "BR-3" manufactured by Toyo Seiki Seisakusho Co., Ltd., in accordance with the method of JIS K 7126.

[0117] [Compression set rate] A circular sheet of 29 mm diameter x 2 mm thickness was prepared from a 2 mm thick sheet using a 29 mm diameter circular punching blade, and inserted into a cylindrical mold of 12.5 mm height and 29 mm diameter. The sheet was hot-pressed for 5 minutes using a hot press machine (Toho Machinery Co., Ltd., hydraulic molding machine TB-50-2 type) heated to 200°C, followed by cold pressing for 5 minutes to prepare a cylindrical test piece of 12.5 mm thickness and 29 mm diameter. The compression set rate (CS) was measured at a compression rate of 25%, at a temperature of 70°C, and for 24 hours according to a method in accordance with JIS K 6262.

[0118] [Ozone Resistance Test] A sheet measuring 2 mm thick, 50 mm wide, and 50 mm long was left to stand without distortion in a testing machine (device: Ozone Weather Meter OZWM-150A, manufactured by Suga Test Instruments Co., Ltd.) with an ozone concentration of 10 ppm and a flow rate of 12 to 16 mm / sec at a temperature of 23°C and a humidity of 50% RH for 40 hours, and then the sheet was checked for changes in appearance, stickiness, and bleeding. A: When the panelist felt the surface, there was no stickiness or bleeding. B: When the panelist felt the surface, there was stickiness. C: There was some bleeding. F: There was significant bleeding and the sheet was sticky.

[0119] [Bending Stress Test] A bending test was carried out on a sheet having a thickness of 2 mm, a width of 50 mm and a length of 50 mm in accordance with JIS K7171, and the bending stress (MPa) was calculated from the results of the bending test.

[0120] [Mechanical Strength (Tensile Strength and Elongation at Break)] A sheet having a thickness of 2 mm, a width of 50 mm, and a length of 50 mm was cut using a die-cutting machine to prepare a No. 3 test piece (20 mm long) according to JIS K7113. This test piece was pulled at a speed of 200 mm / min in a temperature environment of 23°C using a tensile tester (Autograph AG-50kND model) manufactured by Shimadzu Corporation. The stress (MPa) at break of the test piece was recorded as the tensile strength. Furthermore, the elongation at break ((length of test piece at break (mm) - 20) / 20 x 100, %) was calculated from the length of the test piece at break.

[0121]

[0122] The effect of Component C was investigated in Example 1 and Comparative Examples 1 to 3. Example 1 used hydrogenated polybutene as Component C-1, and therefore had better gas barrier performance than Comparative Example 1, which used paraffin oil as Component C-4, which does not fall under Component C. Furthermore, Example 1 had better ozone resistance than Comparative Examples 2 and 3, which used non-hydrogenated polybutenes as Component C-2 or C-3, which do not fall under Component C.

[0123]

[0124] In Examples 2 to 4 and Reference Example 1, the amount of Component C used was investigated. It was found that when the amount of Component C-1 used was in the range of 20 to 250 parts by mass, the gas barrier performance and ozone resistance were excellent, and further, when the amount of Component C-1 used was in the range of 50 to 250 parts by mass, the gas barrier performance, compression set, and ozone resistance were excellent.

[0125]

[0126] In Examples 5 to 7, the amount of Component E used was investigated. In Examples 5 to 7, 10 to 50 parts by mass of the polyphenylene ether resin of Component E was added to the composition of Example 1. As a result, the gas barrier properties were improved compared to Example 1, and an effect of improving compression set was observed as the amount used increased. In Example 8, a filler was further added to the composition of Example 7. As a result, the gas barrier performance of Example 8 was improved compared to Example 7.

[0127]

[0128] In Examples 9 to 11, the effects of using a hydrogenated polybutene (Component C-1) in combination with paraffin oil (Component C-4) were examined. In Example 11, a styrene-based elastomer (Component A-2) was used instead of Component A-1, and the hydrogenated polybutene (Component C-1) was used in combination with paraffin oil (Component C-4). As a result, excellent ozone resistance and gas barrier properties were achieved. In Example 12, a styrene-based elastomer (Component A-2) was used in combination with a styrene-isobutylene-styrene copolymer (Component A-3) instead of Component A-1. As a result, excellent ozone resistance and gas barrier properties were achieved.

[0129] The thermoplastic elastomer composition of the present invention can be used for sheets, extruded films, tubes, seal packings, etc., which are used in the fields of electric and electronic products, vehicles, packaging, and medical care. The thermoplastic elastomer composition of the present invention can be particularly suitably used for tube parts that require flexibility for transporting liquids.

Claims

1. Component A: A block copolymer containing a polymer block a containing a structural unit derived from an aromatic vinyl compound and a polymer block b containing a structural unit derived from a conjugated diene compound, having a weight average molecular weight of 150,000 or more and 500,000 or less, wherein the structural unit derived from the aromatic vinyl compound in Component A is 10% by mass or more and 65% by mass or less, and the hydrogenation rate of the polymer block b is 80% or more. Component B: An olefin polymer, and Component C: A hydrogenated product of polybutene having a kinematic viscosity at 100 °C of 100 mm ２ / s or more and 3,000 mm ２ / s or less, and the content of Component B is 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of Component A. A thermoplastic elastomer composition.

2. The thermoplastic elastomer composition according to claim 1, wherein the content of component A is 5% by mass or more and 70% by mass or less, the content of component B is 0.5% by mass or more and 25% by mass or less, and the content of component C is 5% by mass or more and 80% by mass or less.

3. The thermoplastic elastomer composition according to claim 1 or 2, further comprising 1 part by mass or more and 150 parts by mass or less of the following component E per 100 parts by mass of component A. Component E: polyphenylene ether resin 4. The thermoplastic elastomer composition according to any one of claims 1 to 3, further comprising 10 parts by mass or more and 300 parts by mass or less of the following component F per 100 parts by mass of component A. Component F: filler 5. The thermoplastic elastomer composition according to any one of claims 1 to 4, which is for extrusion molding.

6. The thermoplastic elastomer composition according to any one of claims 1 to 5, which is for tubes.

7. A molded article obtained by extrusion molding the thermoplastic elastomer composition according to any one of claims 1 to 6.

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