Thermoplastic elastomer composition

Abstract

To provide a thermoplastic elastomer composition from which a molded article having creep resistance can be obtained.SOLUTION: A thermoplastic elastomer composition contains: a component A that contains a block copolymer comprising a polymer block a containing a constitutional unit derived from an aromatic vinyl compound and a polymer block b containing a constitutional unit derived from a conjugated diene compound; a component B that is an olefin polymer; a component C that is a polybutene and / or a hydrogenated product of the polybutene; a component D that is a constitutional unit derived from a (meth)acrylic acid ester; and an acrylic polymer having a weight average molecular weight of 400,000 or more; wherein the content of the component B is 1 part by mass or more and 50 parts by mass or less, the content of component C is 30 parts by mass or more and 400 parts by mass or less, and the content of the component D is 1 part by mass or more and 50 parts by mass or less, based on 100 parts by mass of the component A.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a thermoplastic elastomer composition.

Background Art

[0002] Conventionally, as a rubber product having excellent gas barrier properties, Patent Document 1 etc. disclose a crosslinked product of butyl rubber. Since the rubber crosslinked product deteriorates by contacting with the atmosphere, there is a concern that the performance may deteriorate due to long-term use. On the other hand, Patent Document 2 discloses a thermoplastic elastomer as a material having excellent gas barrier properties. Since the thermoplastic elastomer has no crosslinked component, it is less likely to deteriorate when contacting with the atmosphere, but permanent deformation may occur when receiving compressive or extensional (tensile) stress for a long time. Therefore, when using such a thermoplastic elastomer for a connecting portion, there is a concern about seal leakage etc. Thus, even when using a thermoplastic elastomer, there remain unstable points in long-term reliability.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, the problem of the present invention relates to providing a thermoplastic elastomer composition capable of obtaining a molded article having resistance to compressive or extensional (tensile) stress, that is, creep resistance.

Means for Solving the Problems

[0005] The present invention relates to the following [1] to [7]. [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, and the structural unit derived from the aromatic vinyl compound in Component A being 10% by mass or more and 65% by mass or less. Component B: An olefin polymer Component C: A polybutene having a number average molecular weight of 800 or more and 2,500 or less and a kinematic viscosity at 100 °C of 100 mm 2 / s or more and 3,000 mm 2 / s or less, and / or a hydrogenated product of the polybutene, and Component D: An acrylic polymer containing a structural unit derived from a (meth)acrylate and having a weight average molecular weight of 400,000 or more comprising: A thermoplastic elastomer composition, wherein, based on 100 parts by mass of Component A, the content of Component B is 1 part by mass or more and 50 parts by mass or less, the content of Component C is 30 parts by mass or more and 400 parts by mass or less, and the content of Component D is 1 part by mass or more and 50 parts by mass or less. [2] Further, the thermoplastic elastomer composition according to [1] above, containing 1 part by mass or more and 100 parts by mass or less of the following Component E, based on 100 parts by mass of Component A. Component E: A polyphenylene ether resin [3] Further, the thermoplastic elastomer composition according to [1] or [2] above, containing 10 parts by mass or more and 300 parts by mass or less of the following Component F, based on 100 parts by mass of Component A. Component F: A filler [4] The thermoplastic elastomer composition according to any one of [1] to [3] above, wherein Component C is a hydrogenated product of polybutene. [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 tubes. [7] A molded article obtained by extrusion molding the thermoplastic elastomer composition according to any one of [1] to [6] above.

Advantages of the Invention

[0006] According to the present invention, it is possible to provide a thermoplastic elastomer composition capable of obtaining a molded article having creep resistance.

Embodiments for Carrying Out the Invention

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

[0008] Component A in the composition of the present invention is a block copolymer containing a polymer block a and a 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. Since the crosslinking component is not the main component in the composition of the present invention, the effect of ozone resistance described later can also be expected.

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

[0010] The polymer block a may contain a compound other than the aromatic vinyl compound as a monomer within a range that does not impair the effects of the present invention. Examples of such a compound include ethylene, acrylonitrile, acrylic ester, vinyl acetate, etc.

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

[0012] The content of the structural unit derived from the aromatic vinyl compound 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, it is 65% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less from the viewpoint of flexibility. In this specification, the content of the structural unit derived from the aromatic vinyl compound can be measured by the measurement method of the composition of the block copolymer described in the examples.

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

[0014] Polymer block b may contain a compound other than the conjugated diene compound as a monomer as long as the effects of the invention are not impaired. Examples of such a compound include styrene, α-olefin, farnesene, etc.

[0015] The proportion of the structural unit derived from the conjugated diene compound in all the structural units constituting polymer block b is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more. In this specification, the content of the structural unit derived from the conjugated diene compound can be measured by the measurement method of the composition of the block copolymer described in the examples.

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

[0017] In Component A, the bonding form of polymer block a and polymer block b is not particularly limited, and it may be any of linear, branched, radial, or a combination of two or more of them. However, from the viewpoint of extrusion moldability, a linearly bonded form is preferred. When polymer block a is represented as "A" and polymer block b is represented as "B", (A-B) l , A-(B-A) m , B-(A-B)n It is preferably in the combined form of (wherein l, m, and n each independently represent an integer of 1 or more). From the viewpoints of mechanical properties, extrusion moldability, etc., (A - B) l and A - (B - A) m , A - (B - A) n -A, and more preferably it is in the combined form represented by A - (B - A) - A. Even more preferably, it is in the combined form of a diblock structure represented by A - B or a triblock structure represented by A - B - A.

[0018] Also, when component A has two or more polymer blocks a or two or more polymer blocks b, the respective polymer blocks a and polymer blocks b may be blocks having the same configuration or different configurations from each other. For example, in the triblock structure represented by [A - B - A], the two polymer blocks A may have the same or different types of aromatic vinyl compounds constituting them.

[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 viewpoints of heat resistance, creep resistance, and ozone resistance. The 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 are hydrogenated. The hydrogenation rate of polymer block b is 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 measurement method of the hydrogenation rate described in the examples.

[0021] The hydrogenated component A may optionally have one or more functional groups such as carboxy group, hydroxy group, acid anhydride group, amino group, epoxy group, etc. in the molecular chain and / or at the molecular terminals, as long as the effects of the present invention are not impaired.

[0022] Specific examples of the 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, and the like. These may be used alone or as a mixture of two or more. From the viewpoints of creep resistance and gas barrier properties, SEBS, SEPS, and SEEPS are preferred, and SEBS is more preferred. In addition, within the range not impairing the effects of the present invention, generally available Kaneka Corporation's SIBSTAR series such as styrene-isobutylene-styrene block copolymer (SIBS) may be used together with the component A.

[0023] The weight average molecular weight of the component A is 150,000 or more and 500,000 or less. From the viewpoints of preventing deterioration of physical properties such as strength and creep resistance and formability during extrusion molding, and ensuring the moldability of hollow products such as tubes, the weight average molecular weight of the component A is 150,000 or more, preferably 180,000 or more, more preferably 200,000 or more. On the other hand, from the viewpoint of preventing deterioration of the moldability of the extruded molded product, the weight average molecular weight of the component A is 500,000 or less, preferably 450,000 or less, more preferably 400,000 or less. In this specification, the weight average molecular weight (Mw) of the component A can be measured by the method for measuring the 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 indicating the amount of the side chains of the conjugated diene polymer molecular chain. From the viewpoint of gas barrier properties, the amount of 1,2-vinyl bonds in Component A is preferably 10% by mass or more, more preferably 15% by mass or more, still more preferably 20% by mass or more in the conjugated diene compound. On the other hand, from the viewpoints of creep resistance and ozone resistance, it is preferably 70% by mass or less, more preferably 60% by mass or less, still more preferably 50% by mass or less in the conjugated diene compound. In the present specification, the amount of 1,2-vinyl bonds can be measured by the measurement method of the content of 1,2-vinyl bond units described in the examples.

[0025] As the content of Component A in the composition of the present invention, from the viewpoint of imparting flexibility and heat resistance to the composition, it is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, while it is preferably 70% by mass or less, more preferably 60% by mass or less, still more preferably 50% by mass or less.

[0026] Component A can be produced by a conventionally known method. Component A is available as a commercial product. Examples of commercial products include the Clayton G series, Clayton FG series, Clayton MD series, Clayton A series manufactured by Clayton Polymer Co., Ltd., the Tough Tech series, S.O.E. series manufactured by Asahi Kasei Corporation, the Septon series, Hybrid series manufactured by Kuraray Co., Ltd., and the like.

[0027] Component B in the composition of the present invention is an olefin polymer. Component B has excellent miscibility with Component A, and at the initial stage during the melt production of the composition of the present invention, it gives a strong shearing force (kneading force) to Component A, and further has the effect of reducing the viscosity of Component A as the mixing progresses. Therefore, it promotes the dispersion of Component A and reduces the generation of lumps due to poor kneading. Furthermore, when Component B is mixed with Component A, it has the effect of improving the strength, heat resistance, and moldability of the composition.

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

[0029] From the viewpoint of heat resistance, the melting point of Component B is preferably 100°C or higher, and from the viewpoint of moldability, it is preferably 200°C or lower. From these viewpoints, the range of the melting point of Component B is more preferably 120 to 190°C, still more preferably 140 to 185°C, and still 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] From the viewpoint of moldability, the melt mass flow rate of Component B at 230°C and 21 N is preferably 0.1 g / 10 min or more, and from the viewpoint of moldability, it is preferably 100 g / 10 min or less. From these viewpoints, the range of the melt mass flow rate of Component B at 230°C and 21 N is preferably 0.1 to 100 g / 10 min, more preferably 0.5 to 80 g / 10 min, and still 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] From the viewpoint of heat resistance, the flexural modulus of Component B is preferably 30 MPa or more, and from the viewpoint of flexibility, it is preferably 2,500 MPa or less. From these viewpoints, the range of the flexural modulus of Component B is more preferably 50 to 2,000 MPa, still more preferably 100 to 1,850 MPa, and still 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] As for the ratio of component A and component B in the composition of the present invention, from the viewpoints of kneadability with component A and extrusion moldability, component B is 1 part by mass or more, preferably 3 parts by mass or more, more preferably 5 parts by mass or more with respect to 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, component B is 50 parts by mass or less, preferably 30 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 15 parts by mass or less with respect to 100 parts by mass of component A.

[0033] As for the content of component B in the composition of the present invention, from the viewpoints of kneadability with component A and extrusion moldability, it is preferably 0.5% by mass or more, more preferably 1% by mass or more, still more preferably 1.5% by mass or more. On the other hand, 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, still more preferably 5% by mass or less.

[0034] Component B can be produced by a conventionally known method. Component B is available as a commercial product. Examples of commercial products include the PM series manufactured by Sun Allomer Co., Ltd., the Novatec PP series manufactured by Nippon Polypropylene Co., Ltd., and the Prime Polypro series manufactured by Prime Polymer Co., Ltd.

[0035] Component C in the composition of the present invention is polybutene and / or a hydrogenated product of the polybutene. The polybutene of component C in the present invention is also widely known as polyisobutylene. Component C has the effects of improving flexibility, moldability, gas barrier property and permanent set in the composition of the present invention. From the viewpoint of ozone resistance, a hydrogenated product of polybutene is preferred. The number average molecular weight of component C is 800 or more and 2,500 or less. From the viewpoint of improving the gas barrier property, it is preferably 850 or more, 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 2,000 or less, more preferably 1,500 or less. In the present specification, the number average molecular weight can be measured by the method for measuring the number average molecular weight described in the examples.

[0036] Furthermore, the kinematic viscosity of Component C at 100 °C is 100 mm 2 / s or more and 3,000 mm 2 / s or less. From the viewpoint of improving gas barrier properties, it is preferably 150 mm 2 / s or more, more preferably 200 mm 2 / s or more. On the other hand, from the viewpoints 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, still more preferably 600 mm 2 / s or less. In this specification, the kinematic viscosity can be measured by the method for measuring kinematic viscosity described in the examples.

[0037] Due to ozone in the atmosphere, the unsaturated bond portion in Component C is more likely to be depolymerized, resulting in a decrease in performance such as cracking on the surface of the molded body of the composition of the present invention, deterioration of creep resistance, bleeding, and stickiness. Polybutene is produced by so-called cationic polymerization using butene and isobutene as main raw materials and using 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 remain in the polybutene molecular chain. The remaining unsaturated double bonds are radicalized by ozone in the atmosphere, cleaving the polybutene molecular chain and generating low molecular weight components. The generated low molecular weight components bleed to the surface of the thermoplastic elastomer molded body, causing problems such as stickiness. Therefore, a hydrogenated product of 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 hydrogenated polybutene is preferably 80% or more, more preferably 90% or more, still more preferably 99% or more, and even more preferably 99.8% or more. In this specification, the hydrogenation rate in hydrogenated polybutene can be measured by the method for measuring the hydrogenation rate described in the examples.

[0039] As for the ratio of component A and 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, component C is 30 parts by mass or more, preferably 40 parts by mass or more, more preferably 50 parts by mass or more with respect to 100 parts by mass of component A. On the other hand, from the viewpoint of suppressing stickiness on the surface of the molded body of the composition of the present invention, component C is 400 parts by mass or less, preferably 300 parts by mass or less, more preferably 250 parts by mass or less, still more preferably 200 parts by mass or less with respect to 100 parts by mass of component A.

[0040] As for the content of component C in the composition of the present invention, from the viewpoints of the flexibility and gas barrier properties of the composition of the present invention, it is preferably 5% by mass or more, more preferably 15% by mass or more, still more preferably 20% by mass or more. On the other hand, from the viewpoint of suppressing stickiness on the surface of the molded body of the composition of the present invention, it is preferably 80% by mass or less, more preferably 70% by mass or less, still more preferably 60% by mass or less.

[0041] Component C can be produced by a conventionally known method. Component C is available as a commercial product. Examples of commercial products include Nisseki Polybutene HV series manufactured by ENEOS, Palmrene series manufactured by NOF Corporation, Indopol series and Panarine series manufactured by INEOS, etc. Note that paraffin oil or the like may be added as a softening agent together with component C of the present invention as long as the effects of the present invention are not impaired. Examples of generally available paraffin oils include Diana Process Oil series manufactured by Idemitsu Kosan Co., Ltd., Lucant series manufactured by Mitsui Chemicals, Inc., VIVA - B - FIX series manufactured by H&R, etc.

[0042] Component D in the composition of the present invention is an acrylic polymer having a weight average molecular weight of 400,000 or more and containing a structural unit derived from (meth)acrylic acid ester. Since it is a polar polymer, it has a high molecular cohesive force, and due to its high molecular weight, it has the effect of increasing the melt viscosity and further the melt tension during melt kneading or extrusion molding of the composition of the present invention.

[0043] As a result, it is possible to expect an effect of improving the extrusion moldability by crushing lumps of poor dispersion caused by insufficient kneading of component A, which is one of the causes of surface roughness of the molded body obtained using the composition of the present invention. In addition, the melt viscosity and melt tension during the extrusion molding of the composition of the present invention are adjusted to impart formability during the extrusion molding, improve the extrusion moldability, and furthermore, it is presumed that component A is immiscible at room temperature and forms a unique dispersed phase in the molded body. As a result, it is also possible to expect an effect of improving the creep resistance of acrylic molecules having high cohesive force with respect to the composition of the present invention.

[0044] Component D is not particularly limited except that it is an acrylic polymer containing a structural unit derived from a (meth)acrylic acid ester. However, a polymer containing a structural unit derived from methyl methacrylate is preferable, a methacrylic acid ester-acrylic acid ester copolymer is preferable, and a methacrylic acid alkyl-acrylic acid alkyl copolymer is more preferable.

[0045] Here, “(meth)acryl” means acrylic and / or methacryl. “(meth)acrylic acid ester” means acrylic acid ester and / or methacrylic acid ester. Further, “alkyl acrylate” and “alkyl methacrylate” each mean an alkyl ester of acrylic acid and an alkyl ester of methacrylic acid, respectively.

[0046] The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms. Examples of the (meth)acrylic acid alkyl having an alkyl group having 1 to 4 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate. As the methacrylic acid ester, methyl methacrylate (MMA) is preferable from the viewpoint of increasing the melt viscosity. As the acrylic acid ester, normal butyl acrylate (n-BA), isobutyl acrylate (i-BA), and 2-ethylhexyl acrylate (HA) are preferable from the viewpoint of affinity with component A of the present invention.

[0047] As the alkyl methacrylate-alkyl acrylate copolymer, from the viewpoints of extrusion moldability and creep resistance, a copolymer of an alkyl methacrylate and normal butyl acrylate is preferable, and a copolymer of methyl methacrylate and normal butyl acrylate is more preferable. Here, as the ratio of the alkyl methacrylate and the alkyl acrylate, 95 to 55% by mass and 45 to 10% by mass are preferable respectively, 90 to 60% by mass and 40 to 10% by mass are more preferable respectively, and 88 to 80% by mass and 12 to 20% by mass are still more preferable respectively. A random copolymer in which methyl methacrylate and normal butyl acrylate are randomly bonded or a block copolymer having a block polymerization unit in which normal butyl acrylate is repeatedly bonded is more preferable. In addition, considering the copolymerizability of the alkyl methacrylate and the normal butyl acrylate, since a small block of the normal butyl acrylate is naturally generated, such a block may be present in the alkyl methacrylate-alkyl acrylate copolymer. In this specification, the ratio of the alkyl methacrylate and the alkyl acrylate can be measured by the measurement method of pyrolysis gas chromatography / mass spectrometry described in the examples.

[0048] Component D may further contain at least one other vinyl monomer copolymerizable with the (meth)acrylate ester as a constituent unit. Here, from the viewpoint of creep resistance, the ratio of the (meth)acrylate ester is preferably 70% by mass or more, more preferably 90% by mass or more, still more preferably 100% by mass. On the other hand, the ratio of the "other vinyl monomer" is preferably 30% by mass or less, more preferably 10% by mass or less, still more preferably 0% by mass.

[0049] The molecular structure of component D may be any of a linear structure, a branched structure, a graft structure grafted on a crosslinked rubber, and a so-called core-shell rubber. However, from the viewpoints of increasing the melt viscosity, improving the extrusion moldability, and further preventing the generation of lumps due to the crosslinking component, an uncrosslinked linear structure and a branched structure are preferable. More preferably, from the viewpoint of increasing the melt viscosity, it is a linear structure.

[0050] From the perspective 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. On the other hand, from the perspective of extrusion moldability, it 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 the weight-average molecular weight described in the examples.

[0051] Regarding the ratio of Component A and Component D in the composition of the present invention, from the perspective of improving the extrusion moldability and creep resistance of the composition of the present invention, Component D is 1 part by mass or more, preferably 2 parts by mass or more, and more preferably 4 parts by mass or more with respect to 100 parts by mass of Component A. On the other hand, from the perspective of maintaining the flexibility of the composition of the present invention, Component D is 50 parts by mass or less, preferably 30 parts by mass or less, and more preferably 20 parts by mass or less with respect to 100 parts by mass of Component A.

[0052] Regarding the content of Component D in the composition of the present invention, from the perspective of improving the extrusion moldability and creep resistance of the composition of the present invention, it 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. On the other hand, from the perspective of maintaining the flexibility of the composition of the present invention, it is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.

[0053] Component D can be produced by a conventionally known method. Component D is available as a commercial product. Examples of commercial products include those known as acrylic processing aids such as "Metablen P series" from Mitsubishi Chemical Corporation, "Paraloid K series" from Dow Chemical Company, and "Kaneka PA series" from Kaneka Corporation.

[0054] Component E in the composition of the present invention is a polyphenylene ether resin. Component E is miscible with the polymer block a containing structural units derived from the aromatic vinyl compound of component A, and has the effect of raising the glass transition point 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.

[0055] Specific examples of component E include, for example, 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), poly(2,6-dichloro-1,4-phenylene ether), and copolymers of 2,6-dimethylphenol and other phenols (for example, copolymers with 2,3,6-trimethylphenol and copolymers with 2-methyl-6-butylphenol as described in Japanese Patent Publication No. 52-17880) and other polyphenylene ether copolymers. Furthermore, the polyphenylene ether resin may be a modified polyphenylene ether resin in which all or part is modified.

[0056] From the viewpoint of miscibility, the reduced viscosity of component E is preferably 0.1 dL / g or more, and from the viewpoints of dispersibility and the surface property of the molded body, 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 still more preferably 0.2 dL / g to 0.45 dL / g. In this specification, the reduced viscosity can be measured by the method for measuring the reduced viscosity described in the examples.

[0057] From the perspective of compression set resistance, the glass transition temperature of component E is preferably 170°C or higher, and from the perspective of thermal degradation during the production of the composition, it is preferably 260°C or lower. From these perspectives, the glass transition temperature of component E is preferably 170 - 260°C, more preferably 180 - 250°C, and even more preferably 190 - 240°C. In this specification, the glass transition temperature can be measured by the method for measuring the glass transition temperature described in the examples.

[0058] When the composition of the present invention contains component E, from the perspective of improving the compression set resistance of the composition of the present invention, the ratio of component A to component E is 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 with respect to 100 parts by mass of component A. On the other hand, from the perspective of flexibility, component E 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 with respect to 100 parts by mass of component A.

[0059] 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 perspective of improving the compression set resistance of the composition of the present invention. On the other hand, from the perspective 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.

[0060] Component E can be produced by a conventionally known method. Component E is available as a commercial product. Examples of commercial products include the Zylon series manufactured by Asahi Kasei Corporation, the Noryl series manufactured by SABIC Corporation, the Upias series manufactured by Global Polyacetal Corporation, the Remaloy series, and the Bestran series manufactured by Polyplastics Evonik Corporation.

[0061] The filler of component F can be expected to have the effect of improving the gas barrier property of the composition of the present invention. Therefore, it is preferable that the composition of the present invention contains component F.

[0062] 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.

[0063] From the perspective of gas barrier properties, the shape of Component F is preferably one with a large plate surface area relative to the particle size, such as plate-shaped or flaky fillers. More specifically, from the perspective of gas barrier properties, the aspect ratio represented by the major axis / thickness of Component F is preferably 1.1 or more, more preferably 1.2 or more. From the perspective 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. From the perspective of gas barrier properties, the shape of Component F is preferably one with a large plate surface area relative to the particle size, such as plate-shaped or flaky fillers.

[0064] It is preferable to define the filler of Component F of the present invention within a specific range of volume-based median diameter (D50) and aspect ratio. It is widely known that plate-shaped or flaky inorganic fillers are superior in gas barrier properties compared to organic materials such as Component A and Component B of the present invention. However, the influence of the volume-based median diameter (D50), particularly the aspect ratio, on compression set resistance is not known. Compression set resistance means that in an environment of high temperature (70°C in the present invention), a constant strain compressive force is applied to a thermoplastic elastomer molded body for several tens of hours, causing displacement (creep) due to the stress load of thermoplastic elastomer molecules such as Component A, and immediately after releasing the constant strain compressive force, it is used as an index to measure whether the displacement (creep) is restored or whether displacement (creep) has occurred. This deviation (creep) phenomenon is considered to be in a state where creep is more likely to occur at the filler interface than in the matrix part due to stress concentration by compressive force, especially at the interface of particularly hard inorganic fillers in the thermoplastic elastomer composition. In addition, the deviation (creep) of the thermoplastic elastomer molecules generated at the filler interface becomes a resistance to creep recovery at the interface of the inorganic filler and is considered to be in a state where it is difficult to recover immediately after releasing the constant strain compressive force. The inventors of the present invention have found that this phenomenon is more likely to occur as the aspect ratio increases. Also, regarding tensile stress, stress concentration at the filler interface similarly occurs, leading to a decrease in mechanical strength. Therefore, it is preferable to define the upper limit of the aspect ratio of Component F of the present invention in consideration of the adverse effect on compression set resistance, and it is preferable to define the lower limit in order to obtain the effect of improving gas barrier properties.

[0065] Regarding the particle size of Component F, from the viewpoints of extrusion moldability and gas barrier properties, the volume-based median diameter is preferably 150 μm or less, more preferably 50 μm or less, still more preferably 20 μm or less, and on the other hand, preferably 0.1 μm or more, more preferably 1 μm or more, still more preferably 10 μm or more. In this specification, the volume-based median diameter can be measured by the measurement method of the volume-based median diameter (D50) described in the examples.

[0066] When the composition of the present invention contains Component F, from the viewpoint of gas barrier properties, the ratio of Component A to Component F is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, still more preferably 40 parts by mass or more with respect to 100 parts by mass of Component A. On the other hand, from the viewpoint of flexibility, the ratio of Component F is preferably 300 parts by mass or less, more preferably 250 parts by mass or less, still more preferably 200 parts by mass or less with respect to 100 parts by mass of Component A.

[0067] 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, still more preferably 20% by mass or more from the viewpoint of gas barrier properties. On the other hand, from the viewpoint of flexibility, it is preferably 60% by mass or less, more preferably 50% by mass or less, still more preferably 40% by mass or less.

[0068] Component F can be produced by a conventionally known method. Component F is available as a commercial product. Examples of commercial products include fine powder talc series, general-purpose talc series manufactured by Nippon Talc Co., Ltd., P talc, and Hi-Tron series manufactured by Takehara Chemical Industry Co., Ltd.

[0069] The composition of the present invention may contain, if necessary, within a range not impairing the effects of the present invention, organic fillers (for example, wood powder, cellulose powder, organic fibers), antioxidants (for example, phenolic, sulfur-based, and phosphorus-based), softeners other than component C of the present invention, weather resistance stabilizers, ultraviolet absorbers (for example, benzotriazole-based, triamine-based, anilide-based, and benzophenone-based), heat stabilizers, anti-aging agents, light stabilizers (for example, hindered amine-based and benzoate-based), antistatic agents, nucleating agents, pigments, adsorbents (for example, metal oxides), metal chlorides (for example, iron chloride and calcium chloride), hydrotalcite, aluminate, lubricants (for example, fatty acids, higher alcohols, aliphatic amides, and aliphatic esters), flame retardants, foaming agents, silicone compounds, and other various additives.

[0070] Regarding the total amount of component A, component B, component C, and component D in the thermoplastic elastomer composition of the present invention, from the viewpoint of adjusting the flexibility, gas barrier properties, creep resistance, and extrusion moldability aimed at by the present invention, it is preferably 20% by mass or more, more preferably 40% by mass or more, still more preferably 50% by mass or more. The upper limit value of the total amount is 100% by mass, but it is preferably 90% by mass or less, more preferably 80% by mass or less, still more preferably 70% by mass or less.

[0071] The thermoplastic elastomer composition of the present invention is obtained by mixing raw materials including component A, component B, component C, and component D, and further, if necessary, component E and / or component F, and various additives, etc., and solidifying by cooling.

[0072] The "mixing" referred to in the present invention is not particularly limited as long as various components are well mixed. The various components may be dissolved and mixed in an organic solvent capable of dissolving them, or may be mixed by heat melting and kneading. However, the mixing of the raw materials is preferably carried out under conditions where the raw materials other than component F are melted.

[0073] When heat melting and kneading, a general extruder can be used. In order to improve the kneading state, it is preferable to use a multi-screw extruder having two or more screws. The supply to the extruder may be a mixture of various components previously mixed using a mixing device such as a Henschel mixer supplied from one hopper, or each component may be charged into two hoppers and supplied while being metered by a screw or the like under the hopper.

[0074] The product obtained by mixing the raw materials constituting the thermoplastic elastomer composition can be formed into shapes such as pellets and sheets according to the use. For example, it is heated and melt-kneaded by an extruder and extruded into strands, and while being cooled in cold water, it is cut into pellets such as cylindrical or rice grain shapes by a cutter.

[0075] The thermoplastic elastomer composition of the present invention can be made into a thermoplastic elastomer molded body by various known molding methods, such as extrusion molding, press molding, injection molding, calender molding, blow molding, foam molding, and the like. Therefore, one of the preferred uses of the thermoplastic elastomer composition of the present invention is extrusion molding because, needless to say, injection molding in which the mold surface is transferred, but even without mold surface transfer, it has excellent extrudability of the extruded molded body. Furthermore, molded bodies such as sheets and pellets can be secondary processed by thermoforming or the like again.

[0076] The A hardness of the thermoplastic elastomer composition of the present invention in accordance with JIS K 6253 is preferably 10 points or more, more preferably 20 points or more, and still more preferably 30 points or more from the viewpoint of heat resistance. Further, from the viewpoint of flexibility, it is preferably 90 points or less, more preferably 70 points or less, and still more preferably 60 points or less.

[0077] The melt mass flow rate of the thermoplastic elastomer composition of the present invention at 230 °C under a load of 49 N in accordance with JIS K 7210-1 is preferably 0.05 g / 10 min or more, more preferably 0.1 g / 10 min or more, and still more preferably 0.2 g / 10 min or more from the viewpoint of extrusion productivity. From the viewpoints of extrusion moldability and shapeability, it is preferably 50 g / 10 min or less, more preferably 20 g / 10 min or less, and still more preferably 15 g / 10 min or less.

[0078] The thermoplastic elastomer composition of the present invention can obtain a molded article having resistance (also referred to as tensile permanent elongation) to compressive (also referred to as compression set) or tensile stress, that is, creep resistance. In particular, a molded article having creep resistance at a high temperature, for example, 70 °C can be obtained. Therefore, the thermoplastic elastomer composition of the present invention can be particularly preferably used for tube parts that require flexibility for transporting liquids that can reach high temperatures. Further, not only at high temperatures but also in the temperature range around room temperature, a molded article having long-term creep resistance can be obtained.

[0079] Examples of the performance evaluation items required for such a liquid transport tube include permanent distortion (creep resistance), excellent extrusion moldability with smoothness, gas barrier performance, ozone resistance, and the like.

[0080] Permanent distortion (creep resistance) refers to the durability against long-term compressive or tensile stress. It is a compressive strain resistance performance such that when the tube is crushed with a clip or the like to stop the liquid flow, and then the clip is removed, the liquid flow path can be immediately released. When inserted into a connection port with a diameter larger than the inner diameter of the tube, it is more preferable to have a tensile creep performance that creeps over a long period without breaking.

[0081] Excellent extrusion formability with smoothness refers to the surface property for preventing liquid blockage by growing bubbles starting from minute irregularities on the inner surface of the tube. Especially when not used for a long time, gas pockets may form inside the tube, and the content liquid may be blocked. Therefore, it is preferable that the surface of the molded body is smoother.

[0082] Gas barrier performance is more important for tubes with a larger surface area per inner diameter compared to hoses, and is a performance required to prevent oxidative degradation of the content liquid components and liquid blockage due to bubbles.

[0083] Ozone resistance is the long-term physical property stability against the degradation of physical properties by ozone in the atmosphere, and further, the effect of suppressing the elution of low molecular weight components generated by ozone oxidation into the content liquid and the degradation of the quality of the content liquid.

Examples

[0084] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. Various physical properties of the raw materials used in the examples and the like were measured by the following methods.

[0085] <Component A: Block copolymer> 〔Weight average molecular weight (Mw)〕 The weight average molecular weight (Mw) was determined as the weight average molecular weight in terms of polystyrene by gel permeation chromatography under the following measurement conditions. Measuring device · Pump: PU-980 manufactured by JASCO (JASCO Corporation, Japan) · Column oven: AO-50 manufactured by Showa Denko K.K. ·Detector: Hitachi, RI (Differential Refractometer) detector, L-3300 ·Column type: One each of "K-805L (8.0×300 mm)" and "K-804L (8.0×300 mm)" manufactured by Showa Denko K.K. are used in series ·Column temperature: 40 °C ·Guard column: K-G (4.6×10 mm) ·Eluent: Chloroform ·Eluent flow rate: 1.0 mL / min ·Sample concentration: Approximately 1 mg / mL ·Sample solution filtration: Disposable filter with a pore size of 0.45 μm made of polytetrafluoroethylene ·Standard sample for calibration curve: Polystyrene manufactured by Showa Denko K.K.

[0086] 〔Composition of block copolymer〕 Proton NMR measurement was carried out using a nuclear magnetic resonance apparatus (manufactured by BRUKER, Germany, DPX-400). For example, the content of the structural unit derived from styrene and / or styrene derivative was determined by quantifying the characteristic groups of styrene. The content of other monomer units can also be determined by proton NMR measurement.

[0087] 〔Content of 1,2-vinyl bond units in polymer block b〕 The block copolymer before hydrogenation was dissolved in CDCl3 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.

[0088] <Component B: Olefin polymer> 〔Melt mass flow rate (MFR)〕 It was measured under the conditions of 230 °C and a load of 21 N by a method in accordance with JIS K6921-2.

[0089] 〔Flexural modulus〕 A test piece with a length of 80 mm, a width of 10 mm, and a thickness of 4 mm was measured by a three-point bending test at a speed of 2 mm / min according to the method conforming to JIS K7171.

[0090] 〔Melting point〕 The melting point was measured in accordance with ISO11357-3 using a differential scanning calorimeter under a nitrogen atmosphere at a heating rate of 10 °C / min to measure the melting peak temperature.

[0091] <Component C: polybutene and / or hydrogenated product of the polybutene> 〔Kinematic viscosity〕 It was measured at temperatures of 100 °C and 40 °C using a Brookfield type rotational viscometer in accordance with JIS K 7117-1.

[0092] 〔Hydrogenation rate〕 The hydrogenation rate in the hydrogenated product of polybutene was determined by the area ratio of the signal intensities of the signals due to saturated carbon bonds and the signals due to unsaturated carbon bonds when measured by proton NMR. Hereinafter, this ratio is also referred to as the saturated / unsaturated signal.

[0093] 〔Weight-average molecular weight (Mw), number-average molecular weight (Mn)〕 The weight-average molecular weight was determined in the same manner as that of the block copolymer of Component A. The number-average molecular weight was also determined in the same manner as that of Component A to obtain the number-average molecular weight in terms of polystyrene.

[0094] <Component D: acrylic polymer> 〔Weight-average molecular weight (Mw)〕 It was determined in the same manner as that of the block copolymer of Component A.

[0095] 〔MMA / n-BA ratio〕 The MMA / n-BA ratio was determined as follows. It was quantified by the peak ratio of identification and detection by mass, obtained by pyrolysis gas chromatography / mass spectrometry (GC / MS). Mass spectrometer: JMS-T100GC manufactured by JEOL Pyrolyzer: PY2020D manufactured by Frontier Lab Gas chromatograph: Agilent 6890N manufactured by Agilent Technologies Column: DB-SMS Gas flow rate: 1.0 ml / min Pyrolysis temperature: 550 °C

[0096] <Polyphenylene ether resin of Component E> [Reduced viscosity] The reduced viscosity of Component E was taken as the viscosity at 30 °C of a solution dissolved at a concentration of 0.5 g / dL in chloroform by a method conforming to JIS K 7367.

[0097] [Glass transition temperature] The glass transition temperature of Component E was measured at the midpoint temperature at a heating rate of 10 °C / min in a nitrogen atmosphere using a differential scanning calorimeter in accordance with ISO 11357-2.

[0098] <Filler of Component F> [Aspect ratio: length / thickness ratio] The aspect ratio of the filler was determined as follows using a scanning electron microscope. As the scanning electron microscope, the SU1510 type manufactured by Hitachi High-Technologies Fielding was used. [Sample preparation] Conductive carbon double-sided tape was attached to an aluminum sample stage for the electron microscope, and after thinly spreading the target filler powder in a tape shape, excess filler powder was removed by air blowing. [Measurement] The sample stage with the sample was installed in the electron microscope apparatus, and at an acceleration voltage of 10 kV, appropriate numbers of magnified photographs with different magnification and positions were taken according to the particle size and aspect ratio (length and thickness) of each filler sample. Thirty arbitrary non-aggregated particles were selected from the particles observed in the photographs, and the average values obtained by measuring their individual lengths and thicknesses using image analysis and measurement software ("WinRooF2015" manufactured by Mitani Shosha) were used.

[0099] [Volume-based median diameter] The volume-based median diameter (D50) of the filler of Component F was determined as follows. In accordance with the laser diffraction / scattering method defined in JIS Z 8825, 0.1 g of the sample was dispersed in 10 mL of deionized water, and the slurry dispersed with ultrasonic waves at 70 w for 30 seconds was measured for particle size distribution using the "Master Sizer 2000" manufactured by Malvern. The 50% value in the volume-based cumulative fraction was taken as the volume-based median diameter.

[0100] <Thermoplastic elastomer composition> 〔A hardness〕 For a stack of three 2-mm-thick sheets (total 6 mm), in accordance with JIS K 6253, the measurement was carried out using a Type A durometer. The A hardness (the value 1 second after the start of the test) with a measurement time of 1 second was measured. The measurement was carried out after conditioning for 1 day in a room at a temperature of 23°C and a humidity of 50%.

[0101] 〔Melt mass flow rate (MFR)〕 In accordance with JIS K 7210-1, the measurement was carried out under the test conditions of 230°C and a load of 49 N.

[0102] Examples 1 to 15 and Comparative Examples 1 to 6 (1) Preparation of thermoplastic elastomer composition (pellets) The components shown in Tables 1 to 5, and 0.5 parts by mass of a hindered phenol-based antioxidant (Irganox 1010, manufactured by BASF) and 0.5 parts by mass of a phosphorus-based antioxidant (Irgafos 168, manufactured by BASF) were charged all at once into the Super Mixer SMV-20Ba manufactured by Kawata with respect to 100 parts by mass of Component A, and the raw material powder obtained by heating and mixing at 60°C to 80°C was supplied from the raw material supply hopper to an extruder and melt-kneaded under the following conditions. The strand-like resin discharged from the extruder was cut by a cutter to a diameter of about 3 mm and a thickness of about 3 mm while being cooled in cold water to obtain pellets.

[0103] <Melt-kneading conditions> Extruder: Shibaura Machine Co., Ltd., twin-screw kneading extruder, TEM-26SX-16 / 1V Cylinder temperature: The temperature condition near the hopper was set at 180 °C, and up to the extruder outlet was set at 240 °C. Screw rotation speed: 400 r / min Extrusion die: A strand die with a diameter of 3 mm Raw material supply rate: 15 kg / h

[0104] (2) Preparation of a 2-mm-thick sheet The pellets were injection-molded under the following conditions to produce a sheet with a width of 125 mm × a length of 125 mm × a thickness of 2 mm.

[0105] <Injection molding conditions> Injection molding machine: 100MSIII-10E (trade name, manufactured by Mitsubishi Heavy Industries, Ltd.) Injection molding temperature: 200 °C Injection pressure: 30% Injection time: 10 sec Mold temperature: 40 °C

[0106] The details of the typical components used in the examples, comparative examples, etc. are summarized below.

[0107] Component A: Styrene-ethylene·butylene-styrene block copolymer (SEBS) (manufactured by Kraton Corporation, Kraton G1651, weight-average molecular weight (Mw): 290,000, styrene content: 33 mass%, 1,2-vinyl bond content: 37 mass%) Component B: Homopolypropylene (manufactured by Sun Allomer Co., Ltd., PM600A, MFR at 230 °C and 21 N: 7.5 g / 10 min, melting point: 163 °C, flexural modulus: 1,680 MPa)

[0108] Component C-1: Hydrogenated polybutene (manufactured by NOF Corporation, Pearl Lime 18, kinematic viscosity at 100 °C: 300 mm 2 / s, kinematic viscosity at 40 °C: 10,500 mm 2 / s, saturation / unsaturation signal: 99.99 / 0.01, weight-average molecular weight: 1,940, number-average molecular weight: 1,000) Component C-2: Polybutene (manufactured by ENEOS Corporation, HV-300, kinematic viscosity at 100 °C: 590 mm 2 / s, kinematic viscosity at 40 °C: 26,000 mm2 / s, saturation / unsaturation signal: 99.65 / 0.35, weight average molecular weight: 3,107, number average molecular weight: 1,400) Component C-3: Polybutene (manufactured by ENEOS, HV-100, kinematic viscosity at 100 °C: 220 mm 2 / s, kinematic viscosity at 40 °C: 9,500 mm 2 / s, saturation / unsaturation signal: 99.47 / 0.53, weight average molecular weight: 1,901, number average molecular weight: 980) Component C-4: Polybutene (manufactured by ENEOS, HV-1900, kinematic viscosity at 100 °C: 3,710 mm 2 / s, kinematic viscosity at 40 °C: 160,000 mm 2 / s, saturation / unsaturation signal: 99.80 / 0.20, weight average molecular weight: 6,500, number average molecular weight: 2,900) Component C-5: Paraffin oil (manufactured by Idemitsu Kosan Co., Ltd., PW-380, kinematic viscosity at 100 °C: 31 mm 2 / s, kinematic viscosity at 40 °C: 408 mm 2 / s, saturation / unsaturation signal: (none), weight average molecular weight: 1,263, number average molecular weight: 1,128) Note that Component C-4 and Component C-5 do not correspond to Component C and are components for comparison with Component C.

[0109] Component D-1: MMA (methyl methacrylate)-n-BA (n-butyl acrylate) copolymer (manufactured by Mitsubishi Chemical Corporation, Metablen P-531A, MMA / n-BA ratio (mass%): 80 / 20, weight average molecular weight (Mw): 4,500,000) Component D-2: MMA-n-BA copolymer (manufactured by Mitsubishi Chemical Corporation, Metablen P-551A, MMA / n-BA ratio (mass%): 88 / 12, weight average molecular weight (Mw): 1,500,000) Component D-3: MMA-n-BA copolymer (manufactured by Mitsubishi Chemical Corporation, Metablen P-550A, MMA / n-BA ratio (mass%): 88 / 12, weight average molecular weight (Mw): 950,000) Component D-4: MMA-n-BA copolymer (manufactured by Mitsubishi Chemical Corporation, Metablen P-570A, MMA / n-BA ratio (mass%): 50 / 50, weight average molecular weight (Mw): 300,000) Component D-5: Polytetrafluoroethylene (PTFE) (manufactured by Mitsubishi Chemical Corporation, Metablen A-3000A, MMA / n-BA ratio (mass%): (none), weight average molecular weight (Mw): (none)) Note that Component D-4 is an acrylic processing aid, but its Mw does not apply, and Component D-5 is a PTFE processing aid and does not fall under Component D of the present invention. It is a comparative component for Component D.

[0110] Component E: Polyphenylene ether (PPE) (manufactured by Asahi Kasei Chemicals Corporation, Zylon S202A, reduced viscosity: 0.42 dL / g, Tg: 214 °C) Component F-1: Talc (manufactured by Hayashi Chemical Co., Ltd., TP-TK, volume-based median diameter (D50): 13 μm, aspect ratio: 33, shape: plate-like)

[0111] Using the thermoplastic elastomer compositions obtained in the examples and comparative examples, the following evaluations were carried out. The results are shown in Tables 1 to 5.

[0112] 〔Oxygen Permeability Coefficient〕 From a 2-mm-thick sheet, a piece with a width of 25 mm × a length of 30 mm was cut out. Using a press mold with a thickness of 0.5 mm × a width of 100 mm × a length of 120 mm, a hot press machine (manufactured by Toho Machinery Co., Ltd., hydraulic molding machine TB-50-2 type) heated to 160 °C was used for hot pressing for 2 minutes, and then cooling pressing for 3 minutes to produce a sheet-like press-molded body with a thickness of 0.5 mm as a test piece. The test piece dimensions were 90 mm × 90 mm × 0.5 mm, and the permeation area was 38.5 cm 2 of this size was used. Measured at 23 °C using a gas permeability measuring device "BR-3" manufactured by Toyo Seiki Seisaku-sho, Ltd. according to the method in accordance with JIS K 7126.

[0113] 〔Compression Set Ratio〕 A circular sheet with a diameter of 29 mm and a thickness of 2 mm was produced from a 2-mm-thick sheet using a circular punching blade with a diameter of 29 mm, inserted into a cylindrical mold with a height of 12.5 mm and a diameter of 29 mm, and 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, and then cooled and pressed for 5 minutes to create a cylindrical test piece with a thickness of 12.5 mm and a diameter of 29 mm. The compression set (CS) was measured in an environment with a compression ratio of 25%, a temperature of 70 °C, and 24 hours according to the method conforming to JIS K 6262.

[0114] 〔High-temperature tensile holding test〕 A No. 3 test piece described in JIS K 6251 was produced from a 2-mm-thick sheet using a die-cutting machine, and markings with a distance of 20 mm between the markings were drawn at positions 10 mm to the left and right from the center. Using a tensile testing machine (Tensilon RTF-1325 type) manufactured by A&D Company, Limited equipped with a constant-temperature bath, the distance between the markings was extended to 40 mm, and the time until the test piece broke (breaking time) was measured while standing still at 70 °C under the condition of 100% elongation.

[0115] 〔Extrusion evaluation: Extrudability〕 A single-screw extruder with a screw diameter of 40 mm (device: manufactured by Ikegai Corporation, FS-40) was used. The barrel temperature was set to 140 - 220 °C and the die temperature was set to 220 °C, and the screw rotation speed was 40 r / min. The surface of the produced tube molded product (tube size: outer diameter 4 mm, inner diameter 2.5 mm) was evaluated for extrudability (unevenness) by a panelist touching it with a finger. The evaluation was performed by sensory evaluation (relative evaluation) based on the following criteria. ◎: The tube surface was smooth and free of bumps. ○: The tube surface was smooth, but there were some bumps. △: The tube surface was not smooth. ×: The undulation of the tube surface was extremely poor.

[0116] 〔Ozone resistance test〕 A sheet with a thickness of 2 mm, a width of 50 mm, and a length of 50 mm was placed in a tester (apparatus: manufactured by Suga Test Instruments Co., Ltd., ozone weather meter OZWM-150A) with an ozone concentration of 10 ppm and a flow rate of 12 - 16 mm / sec without applying strain, and left standing at a temperature of 23°C and a humidity of 50%RH for 40 hours. Then, the appearance change, stickiness, and bleeding of the sheet were confirmed. ◎: As felt by the panelist, there was no stickiness or bleeding on the surface. ○: As felt by the panelist, stickiness was felt on the surface. △: There was a slight amount of bleeding. ×: There was significant bleeding and stickiness.

[0117]

Table 1

[0118] In Examples 1 - 3 and Comparative Examples 1 - 3, the effects of Component D were examined. In Comparative Example 1, Component D was not used, and the time until breakage in the high-temperature tensile retention test was short (i.e., the tensile permanent elongation was poor). In Examples 1 - 3, compared with Comparative Example 1, any of Components D-1 - D-3 (Mw: 400,000 or more) was used, and the tensile permanent elongation was improved. Moreover, it was found from Examples 1 - 3 that the composition of the present invention exhibits creep resistance even at a high temperature of 70°C. Component D-4 used in Comparative Example 2 had a low Mw (300,000), so the tensile permanent elongation was poor. Component D-5 is a polymer that does not contain (meth)acrylate as a constituent unit, and the tensile permanent elongation was poor.

[0119]

Table 2

[0120] In Examples 4 - 5 and Comparative Examples 4 - 5, the effects of the PPE resin of Component E and the filler of Component F were examined respectively. Example 4 is obtained by adding component E to Example 1, and the gas barrier and compression set resistance are improved. Example 5 is obtained by adding component F-1 (talc) to Example 1, and the gas barrier is improved. In Comparative Examples 4 and 5, component D (specifically, component D-1), which is an essential component, was not used with respect to Examples 4 and 5, and the tensile set was poor. Furthermore, in Example 6 and Comparative Example 6, the case where both PPE and filler were used was examined.

[0121] Example 6 uses both component E and component F with respect to Example 1, and compared with Examples 4 to 5, the performance of both the gas barrier and compression set became even more excellent. Comparative Example 6 does not use component D with respect to Example 6, and the tensile set was poor.

[0122]

Table 3

[0123] Examples 7 to 8 and Comparative Examples 7 to 8 examined the differences in the types of component C (polybutene viscosity, paraffin oil). In Examples 7 to 8, the type of component C (polybutene molecular weight and kinematic viscosity) was changed with respect to Example 6. As shown in Table 3, performance equivalent to that of Example 6 was confirmed. In Comparative Example 7, the molecular weight and kinematic viscosity of component C-4 were too high, and the miscibility with component A was poor, so the compression set and tensile set were poor. In Comparative Example 8, paraffin oil of component C-5 was used as a comparison target for component C. This paraffin oil corresponds to a hydrogenated product of polybutene, but it did not correspond to component C in terms of kinematic viscosity at 100 °C. As a result, the gas barrier property was poor.

[0124] On the other hand, regarding ozone resistance, it was good only when using hydrogenated polybutene (C-1 "Pearl Rim", C-5 "paraffin oil"), which is a hydrogenated product of polybutene. When using non-hydrogenated polybutene, bleed products such as "stickiness" occurred on the surface after the ozone resistance test.

[0125]

Table 4

[0126] In Examples 6, 9 to 12 and Comparative Examples 9 to 10, the usage amount of Component C-1 was examined. In Examples 6, 9 to 12, 50 to 300 parts by mass of Component C-1 was used. These showed good physical properties. In Comparative Example 9, 20 parts by mass of Component C-1 was used. As a result, the compression set was poor. In Comparative Example 10, 500 parts by mass of Component C-1 was used. As a result, the miscibility with the styrene-based elastomer was poor and the moldability was poor, so that a gas barrier evaluation test piece could not be produced. Also, the tensile permanent elongation was poor.

[0127]

Table 5

[0128] In Examples 13 to 14, the usage amount of Component D-1 was examined. Based on the amount of Component D-1 in Example 6, the amount was changed. In Example 13, the D-1 component was 5 parts by mass (half of that in Example 6), but the tensile permanent elongation was improved compared to Comparative Example 6 which contained no D component at all. Example 14 showed the same performance as Example 6. Also, in Example 15, the D-2 component was used with respect to Comparative Example 6. As a result, the tensile permanent elongation was improved compared to Comparative Example 6.

Industrial Applicability

[0129] The thermoplastic elastomer composition of the present invention can be used for sheets, extruded films, tubes, seal packings, etc. used in the fields of electric and electronic products, vehicle fields, packaging fields, and medical fields. The thermoplastic elastomer composition of the present invention can be particularly preferably used for tube parts that require flexibility for liquid transportation.

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, and the structural unit derived from the aromatic vinyl compound in Component A being 10% by mass or more and 65% by mass or less, Component B: An olefin polymer, Component C: polybutene having a number average molecular weight of 800 or more and 2,500 or less and a kinematic viscosity at 100 °C of 100 mm ２ / s or more and 3,000 mm ２ / s or less, and / or a hydrogenated product of the polybutene, and Component D: An acrylic polymer containing a structural unit derived from a (meth)acrylate and having a weight average molecular weight of 400,000 or more and comprising, A thermoplastic elastomer composition wherein, based on 100 parts by mass of Component A, the content of Component B is 1 part by mass or more and 50 parts by mass or less, the content of Component C is 30 parts by mass or more and 400 parts by mass or less, and the content of Component D is 1 part by mass or more and 50 parts by mass or less.

2. The thermoplastic elastomer composition according to Claim 1, further comprising the following Component E in an amount of 1 part by mass or more and 100 parts by mass or less based on 100 parts by mass of Component A. Component E: A polyphenylene ether resin

3. The thermoplastic elastomer composition according to Claim 1 or 2, further comprising the following Component F in an amount of 10 parts by mass or more and 300 parts by mass or less based on 100 parts by mass of Component A. Component F: A filler

4. The thermoplastic elastomer composition according to Claim 1 or 2, wherein Component C is a hydrogenated product of polybutene.

5. The thermoplastic elastomer composition according to Claim 1 or 2, which is for extrusion molding.

6. The thermoplastic elastomer composition according to Claim 1 or 2, which is for tubes.

7. A molded article obtained by extrusion molding the thermoplastic elastomer composition according to Claim 1 or 2.

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