Thermoplastic elastomer composition for tube and tube

Abstract

To provide a thermoplastic elastomer composition for a tube for producing a tube capable of making gas barrier properties compatible with resistance to compression or expansion (tensile) stress.SOLUTION: A thermoplastic elastomer composition for a tube contains: a component A-1 that is 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 A-2 that is a block copolymer comprising a polymer block c containing a constitutional unit derived from an aromatic vinyl compound and a polymer block d containing a constitutional unit derived from isobutylene; a component B that is an olefin polymer; a component C that is a softening agent; and a component F that is a filler; wherein the mass ratio of the component A-1 to the component A-2 ([A-1] / [A-2]) is 50 / 50 or more and 85 / 15 or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a thermoplastic elastomer composition for tubes. Further, the present invention relates to a tube formed by extrusion molding the composition.

Background Art

[0002] Thermoplastic elastomers are excellent in flexibility and mechanical strength and are used in a wide range of applications. In applications such as food and medical containers and tubes for electronic devices, further improvement in gas barrier properties is required from the viewpoints of heat resistance performance by high-temperature treatment and protection of the contents. Conventionally, as a means for improving gas barrier properties, Patent Document 1 has proposed an elastomer composition using a thermoplastic elastomer containing an isobutylene block. However, although a thermoplastic elastomer containing an isobutylene block is excellent in gas barrier properties, permanent deformation may occur when it is subjected to compressive or extensional (tensile) stress for a long period of time. Therefore, when using such a thermoplastic elastomer for a tube, concerns such as seal leakage at the connection part arise.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, an object of the present invention is to provide a tube capable of achieving both gas barrier properties and resistance to compressive or extensional (tensile) stress, and a thermoplastic elastomer composition for producing such a tube.

Means for Solving the Problems

[0005] The present invention relates to the following [1] to [4]. 〔1〕 Component A-1: 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, wherein the hydrogenation rate of the polymer block b is 80% or more. Component A-2: A block copolymer containing a polymer block c containing a structural unit derived from an aromatic vinyl compound and a polymer block d containing a structural unit derived from isobutylene. Component B: An olefin polymer Component C: A softening agent, and Component F: A filler which is contained to form The mass ratio of Component A-1 to Component A-2 ([A-1] / [A-2]) is 50 / 50 or more and 85 / 15 or less. Based on 100 parts by mass of the total of Component A-1 and Component A-2, 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 300 parts by mass or less, and the content of Component F is 10 parts by mass or more and 300 parts by mass or less. A thermoplastic elastomer composition for a tube. 〔2〕 The thermoplastic elastomer composition for a tube according to 〔1〕 above, wherein Component C contains at least one softening agent selected from the group consisting of polybutene and paraffin oil. 〔3〕 Furthermore, the thermoplastic elastomer composition for a tube according to 〔1〕 or 〔2〕 above, which contains 1 part by mass or more and 120 parts by mass or less of the following Component E based on 100 parts by mass of the total of Component A-1 and Component A-2. Component E: A polyphenylene ether resin 〔4〕 A tube formed by extrusion molding the thermoplastic elastomer composition for a tube according to any one of 〔1〕 to 〔3〕 above.

Advantages of the Invention

[0006] According to the present invention, it is possible to provide a tube that can achieve both gas barrier properties and resistance to compressive or extensional (tensile) stress. Furthermore, according to the present invention, it is possible to provide a thermoplastic elastomer composition for manufacturing such a tube.

Embodiments for Carrying Out the Invention

[0007] The thermoplastic elastomer composition for a tube of the present invention is a composition containing Component A-1, Component A-2, Component B, Component C, and Component F as essential components.

[0008] The tube of the present invention means a hollow long so-called tubular molded article intended for transporting fluid substances such as gases such as air, liquids such as water, and gases and liquids containing powders. Therefore, in order to produce such a molded article with high productivity, the extrusion molding method is widely known. In addition, single-layer or multi-layer tubes made of a thermoplastic elastomer composition are flexible, so they can be easily bent with a small bending radius, and the inner diameter can be expanded at a connection part larger than the inner diameter of the tube and inserted. Since it is easy to handle, it is widely used as parts for electronic and electrical equipment, machinery, and automobiles. Furthermore, since the thermoplastic elastomer composition of the present invention is excellent in chemical resistance to water, alcohol, and polar organic solvents, it can be used as a tube for transporting fluids containing polar liquids.

[0009] Component A-1 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-1 imparts flexibility, heat resistance, and creep resistance to the composition of the present invention. Since the cross-linking component is not the main component in the composition of the present invention, the effect of ozone resistance described below can also be expected.

[0010] 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 preferable.

[0011] The polymer block a may contain a compound other than an aromatic vinyl compound as a monomer as long as the effects of the present invention are not impaired. Examples of such compounds include ethylene, acrylonitrile, acrylate ester, vinyl acetate, and the like.

[0012] The proportion of the structural unit 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.

[0013] The content of the structural unit derived from the aromatic vinyl compound in the component A-1 is 10% by mass or more, preferably 15% by mass or more, and 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, and more preferably 40% by mass or less from the viewpoint of flexibility. In the present 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.

[0014] The 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, and the like, and two or more of these may be used in combination.

[0015] The 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 compounds include styrene, α-olefin, farnesene, and the like.

[0016] The proportion of the structural unit derived from the conjugated diene compound in all the structural units constituting the polymer block b is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more. In the present 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.

[0017] The block copolymer of Component A-1 contains at least one polymer block a and at least one polymer block b.

[0018] In Component A-1, 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 (wherein l, m, and n each independently represent an integer of 1 or more) is preferably the bonding form, and from the viewpoints of mechanical properties, extrusion moldability, etc., (A-B) l , A-(B-A) m , and A-(B-A) n -A is more preferably the bonding form, and a diblock structure represented by A-B or a triblock structure represented by A-B-A is even more preferably the bonding form.

[0019] Also, when Component A-1 has two or more polymer blocks a or two or more polymer blocks b, each polymer block a and polymer block b may be blocks of 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.

[0020] In Component A-1, 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.

[0021] In the present invention, component A-1 is preferably a hydrogenated product from the viewpoints of heat resistance, creep resistance, and ozone resistance. The hydrogenated component A-1 (hereinafter also referred to as hydrogenated A-1) is substantially a product in which some or all of the unsaturated double bonds (carbon-carbon double bonds) in the polymer block b are hydrogenated. The hydrogenation rate of the polymer block b is preferably 85% or more, more preferably 90% or more, and still more preferably 95% or more. In the present invention, the hydrogenation rate of the polymer block b can be determined by the measurement method of the hydrogenation rate described in the examples.

[0022] The hydrogenated component A-1 may optionally have one or more functional groups such as a carboxy group, a hydroxy group, an acid anhydride group, an amino group, and an epoxy group in the molecular chain and / or at the molecular terminal, as long as the effects of the present invention are not impaired.

[0023] Specific examples of the hydrogenated component A-1 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 extrusion moldability, SEBS, SEPS, and SEEPS are preferred, and SEBS is more preferred.

[0024] In terms of physical properties such as strength and creep resistance, and formability during extrusion molding, the weight average molecular weight of component A-1 is preferably 150,000 or more, more preferably 180,000 or more, and still more preferably 200,000 or more from the perspective of ensuring the formability of hollow products such as tubes. On the other hand, from the perspective of preventing a decrease in the formability of the extruded molded product, the weight average molecular weight of component A-1 is preferably 500,000 or less, more preferably 450,000 or less, and still more preferably 400,000 or less. In this specification, the weight average molecular weight (Mw) of component A-1 can be measured by the method for measuring the weight average molecular weight described in the examples.

[0025] The amount of 1,2-vinyl bonds derived from the conjugated diene compound in component A-1 is an index indicating the amount of the side chain of the conjugated diene polymer molecular chain. From the perspective of gas barrier properties, the amount of 1,2-vinyl bonds in component A-1 is preferably 10% by mass or more, more preferably 15% by mass or more, and still more preferably 20% by mass or more in the conjugated diene compound. On the other hand, from the perspectives of creep resistance and ozone resistance, it is preferably 70% by mass or less, more preferably 60% by mass or less, and still 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.

[0026] Regarding the content of component A-1 in the composition of the present invention, from the perspective of imparting flexibility and heat resistance to the composition, it is preferably 5% by mass or more, more preferably 10% by mass or more, and still more preferably 15% by mass or more, while it is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less.

[0027] Component A-1 can be produced by a conventionally known method. Component A-1 is commercially available. Examples of commercially available 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, Highbler series manufactured by Kuraray Co., Ltd., and the like.

[0028] Component A-2 in the composition of the present invention is a block copolymer containing polymer block c and polymer block d, which will be described in detail below. Component A-2 imparts gas barrier properties to the composition of the present invention. The polymer block a in Component A-1 and the polymer block c in Component A-2 may be the same or different.

[0029] Polymer block c contains structural units derived from aromatic vinyl compounds. Examples of aromatic vinyl compounds include the same compounds as the above polymer block a, and two or more of these may be used in combination. Among these, styrene, which is easily available, is preferred.

[0030] Polymer block c may contain a compound other than an aromatic vinyl compound as a monomer as long as the effects of the present invention are not impaired. Examples of such compounds include ethylene, acrylonitrile, acrylate ester, vinyl acetate, and the like.

[0031] The proportion of the structural units derived from aromatic vinyl compounds in all the structural units constituting polymer block c is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more.

[0032] The content of the structural units derived from aromatic vinyl compounds in Component A-2 is 10% by mass or more, preferably 15% by mass or more, and 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, and more preferably 40% by mass or less from the viewpoint of flexibility. In the present specification, the content of the structural units derived from aromatic vinyl compounds can be measured by the method for measuring the composition of the block copolymer described in the examples.

[0033] The polymer block d contains a structural unit derived from isobutylene.

[0034] The polymer block d may contain a compound other than isobutylene as a monomer as long as the effects of the invention are not impaired. Examples of such compounds include styrene, α-olefin, and farnesene.

[0035] The proportion of the structural unit derived from isobutylene in all the structural units constituting the polymer block d is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more.

[0036] The block copolymer of Component A-2 contains at least one polymer block c and at least one polymer block d.

[0037] In Component A-2, the bonding form of the polymer block c and the polymer block d is not particularly limited and may be any of linear, branched, radial, or a combined form of two or more of them. However, from the viewpoint of extrusion moldability, a linearly bonded form is preferred. When the polymer block c is represented by "C" and the polymer block d is represented by "D", (C-D) l , C-(D-C) m , D-(C-D) n (wherein l, m, and n each independently represent an integer of 1 or more) is preferably the bonding form, and from the viewpoints of mechanical properties, extrusion moldability, etc., (C-D) l and C-(D-C) m , C-(D-C) n -C is more preferably the bonding form, and a diblock structure represented by C-D or a triblock structure represented by C-D-C is even more preferably the bonding form.

[0038] When component A-2 has two or more polymer blocks c or two or more polymer blocks d, each polymer block c and polymer block d may be blocks having the same structure or different structures from each other. For example, in the triblock structure represented by [C-D-C], the two polymer blocks A-2 may have the same or different types of aromatic vinyl compounds constituting them.

[0039] In component A-2, the mass ratio of polymer block c to polymer block d (polymer block c / polymer block d) is preferably 5 / 95 to 70 / 30, more preferably 10 / 90 to 50 / 50, and still more preferably 15 / 85 to 40 / 60 from the viewpoints of flexibility, heat resistance, and gas barrier properties.

[0040] A-2 may optionally have one or more functional groups such as carboxy groups, hydroxy groups, acid anhydride groups, amino groups, and epoxy groups in the molecular chain and / or at the molecular terminals, as long as the effects of the present invention are not impaired.

[0041] Specific examples of A-2 include styrene-isobutylene-styrene block copolymer (SIBS) and styrene-ethylene-isobutylene-styrene block copolymer. These may be used alone or as a mixture of two or more, but from the viewpoint of gas barrier properties, styrene-isobutylene-styrene block copolymer (SIBS) is preferred.

[0042] From the viewpoint of ensuring the formability of hollow products such as tubes, where physical properties such as strength decrease and the formability during extrusion molding deteriorates, the weight average molecular weight of component A-2 is preferably 50,000 or more, more preferably 75,000 or more, and still more preferably 100,000 or more. On the other hand, from the viewpoint of preventing a decrease in the formability of extrusion molded products, the weight average molecular weight of component A-2 is preferably 500,000 or less, more preferably 450,000 or less, and still more preferably 400,000 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.

[0043] As the content of component A-2 in the composition of the present invention, from the viewpoint of imparting gas barrier properties to the composition, it is preferably 5% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more. On the other hand, from the viewpoint of creep resistance, it is preferably 30% by mass or less, more preferably 25% by mass or less, still more preferably 20% by mass or less.

[0044] Component A-2 can be produced by a conventionally known method. Component A-2 is available as a commercial product. Examples of commercial products include the SIBSTAR series manufactured by Kaneka Corporation.

[0045] In the thermoplastic elastomer composition for a tube of the present invention, component A-1 has good compression set and extrusion moldability, but is inferior in gas barrier properties. On the other hand, component A-2 has good gas barrier properties, but is inferior in compression set (creep resistance) and extrusion moldability. Therefore, in order to achieve both good compression set and gas barrier properties and further balance the extrusion moldability, the mass ratio ([A-1] / [A-2]) of component A-1 and component A-2 is defined. The mass ratio ([A-1] / [A-2]) of component A-1 and component A-2 of the present invention is 50 / 50 or more and 85 / 15 or less from the viewpoint of compression set resistance. Here, it is preferably 55 / 45 or more, more preferably 60 / 40 or more. On the other hand, from the viewpoint of gas barrier properties, it is preferably 80 / 20 or less, more preferably 75 / 25 or less.

[0046] As the total content of component A-1 and component A-2 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. On the other hand, it is preferably 70% by mass or less, more preferably 60% by mass or less, still more preferably 50% by mass or less.

[0047] Component B in the composition of the present invention is an olefin polymer. Component B has excellent miscibility with Component A-1 and Component A-2. At the initial stage during the melt production of the composition of the present invention, it applies a strong shearing force (kneading force) to Component A-1 and Component A-2, and further has the effect of reducing the viscosities of Component A-1 and Component A-2 as the miscibility progresses. Therefore, it promotes the dispersion of Component A-1 and Component A-2 and reduces the generation of lumps caused by poor kneading. Furthermore, when Component B is miscible with Component A-1 and Component A-2, it has the effect of improving the strength, heat resistance, and moldability of the composition.

[0048] Examples of the olefin polymer that can be used as Component B include known ones, such as polyethylene, polypropylene, ethylene-propylene copolymer, α-olefin copolymer, etc. Among these, from the viewpoints of heat resistance and miscibility, polypropylene and ethylene-propylene copolymer are preferred. From the viewpoint of heat resistance, polypropylene is more preferably used.

[0049] 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 - 190 °C, still more preferably 140 - 185 °C, and still more preferably 150 - 180 °C. In this specification, the melting point can be measured by the melting point measurement method described in the examples.

[0050] 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 extrusion 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 - 100 g / 10 min, more preferably 0.5 - 80 g / 10 min, and still more preferably 1.0 - 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.

[0051] 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 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 measuring method of the flexural modulus described in the examples.

[0052] In the composition of the present invention, the ratio of Component A-1, Component A-2, and Component B is such that, from the viewpoints of the kneadability and extrusion moldability of Component A-1 and Component A-2, Component B is 1 part by mass or more, preferably 3 parts by mass or more, and more preferably 5 parts by mass or more with respect to 100 parts by mass in total of Component A-1 and Component A-2. 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, and still more preferably 15 parts by mass or less with respect to 100 parts by mass in total of Component A-1 and Component A-2.

[0053] 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 still more preferably 1.5% by mass or more from the viewpoints of the kneadability with Component A-1 and Component A-2 and extrusion moldability. 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, and still more preferably 5% by mass or less.

[0054] 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 Japan Polypropylene Co., Ltd., and the Prime Polypro series manufactured by Prime Polymer Co., Ltd.

[0055] Component C in the composition of the present invention is a softening agent. The plasticizer is not particularly limited as long as it is a plasticizer known in the field of the present invention. For example, component C contains at least one plasticizer selected from the group consisting of polybutene and paraffin oil. Polybutene and / or paraffin oil may be mentioned. The polybutene may be a hydrogenated product. Polybutene is also widely known as polyisobutylene. From the viewpoint of improving gas barrier properties, the number average molecular weight of component C is preferably 300 or more, more preferably 500 or more, and still more preferably 700 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 still more preferably 1,500 or less. In the present specification, the number average molecular weight can be measured by the measurement method of the number average molecular weight described in the examples.

[0056] Furthermore, when component C is polybutene, the kinematic viscosity at 100 °C is preferably 100 mm 2 / s or more, more preferably 150 mm 2 / s or more, and still more preferably 200 mm 2 / s or more from the viewpoint of improving gas barrier properties. On the other hand, from the viewpoints of miscibility with component A-1 and component A-2 and creep resistance, the kinematic viscosity of component C is preferably 3,000 mm 2 / s or less, more preferably 2,000 mm 2 / s or less, still more preferably 1,000 mm 2 / s or less, and still more preferably 600 mm 2 / s or less.

[0057] When component C is paraffin oil, the kinematic viscosity at 40 °C is preferably 30 mm 2 / s or more, more preferably 80 mm 2 / s or more, and still more preferably 150 mm 2 / s or more from the viewpoint of bleeding properties to component A-1 and component A-2. On the other hand, from the viewpoint of miscibility with component A-1 and component A-2, it is preferably 1,000 mm 2 / s or less, more preferably 800 mm 2 / s or less, more preferably 500 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.

[0058] Due to ozone in the atmosphere, the unsaturated bond part in Component C is more likely to be depolymerized, resulting in a decrease in performance such as the occurrence of cracks on the surface of the tube of the present invention, deterioration of creep resistance, easy occurrence of bleeding, and stickiness. Polybutene is mainly made from butene and isobutene and is produced by so-called cationic polymerization 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, as Component C, a hydrogenated polybutene is preferred.

[0059] 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 still 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.

[0060] As for the ratio of component A-1, component A-2, and component C in the composition of the present invention, from the viewpoint 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 in total of component A-1 and component A-2. On the other hand, from the viewpoint of suppressing stickiness on the surface of the tube 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 in total of component A-1 and component A-2.

[0061] As for the content of component C in the composition of the present invention, from the viewpoints of 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 tube 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.

[0062] Both polybutene and / or hydrogenated polybutene used for component C in the present invention and paraffin oil can be used. The weight ratio of polybutene and / or hydrogenated polybutene to paraffin oil is preferably in the range of 1 / 99 to 99 / 1. From the viewpoint of gas barrier properties, the lower limit of polybutene and / or hydrogenated polybutene is more preferably 10 / 90 or more, still more preferably 15 / 85 or more, still more preferably 20 / 80 or more. On the other hand, from the viewpoint of compression set, the upper limit of polybutene and / or hydrogenated polybutene is preferably 90 / 10 or less, more preferably 85 / 15 or less, still more preferably 80 / 20 or less.

[0063] Component C can be produced by a conventionally known method. Component C is commercially available. Examples of commercially available products include the ENEOS Nisseki Polybutene HV series, the NOF Palm Ream series, the INEOS Indopol series, and the Panarine series. Examples of paraffin oils include the Idemitsu Kosan Diana Process Oil series, the Mitsui Chemicals Lucant series, and the H&R VIVA-B-FIX series.

[0064] 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 structural units derived from (meth)acrylic acid esters. 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.

[0065] As a result, it is possible to expect the effect of improving the extrusion moldability by crushing the lumps of poor dispersion caused by insufficient kneading of component A-1, which is one of the causes of surface roughness of the tube obtained using the composition of the present invention. In addition, the melt viscosity and melt tension during extrusion molding of the composition of the present invention are adjusted to impart formability during extrusion molding, improve the extrusion moldability, and furthermore, it is presumed that component A-1 is immiscible at room temperature and forms a unique dispersed phase in the tube. As a result, it is also possible to expect the effect of improving the creep resistance of the acrylic molecules having a high cohesive force with respect to the composition of the present invention.

[0066] Component D is not particularly limited except that it is an acrylic polymer containing structural units derived from (meth)acrylic acid esters. However, a polymer containing structural units derived from methyl methacrylate is preferred, a methacrylic acid ester-acrylic acid ester copolymer is preferred, and a methacrylic acid alkyl-acrylic acid alkyl copolymer is more preferred.

[0067] Here, “(meth)acryl” means acrylic and / or methacrylic. “(meth)acrylate” means acrylate and / or methacrylate. Also, “alkyl acrylate” and “alkyl methacrylate” mean alkyl esters of acrylic acid and alkyl esters of methacrylic acid, respectively.

[0068] 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 alkyl (meth)acrylate having an alkyl group with 1 to 4 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate. As the methacrylate, methyl methacrylate (MMA) is preferred from the viewpoint of increasing the melt viscosity. As the acrylate, n-butyl acrylate (n-BA), isobutyl acrylate (i-BA), and 2-ethylhexyl acrylate (HA) are preferred from the viewpoint of affinity with component A-1 of the present invention.

[0069] 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 normal butyl acrylate is naturally generated, such a block may exist 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.

[0070] 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.

[0071] The molecular structure of component D may be any of a linear structure, a branched structure, a graft structure grafted onto 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.

[0072] 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. On the other hand, from the viewpoint of extrusion moldability, it is preferably 7,000,000 or less, more preferably 6,000,000 or less, and still 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.

[0073] Regarding the ratio of Component A-1, Component A-2, and Component D in the composition of the present invention, from the viewpoint of improving the extrusion moldability and creep resistance of the composition of the present invention, Component D is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and still more preferably 4 parts by mass or more with respect to 100 parts by mass in total of Component A-1 and Component A-2. On the other hand, from the viewpoint of maintaining the flexibility of the composition of the present invention, Component D is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and still more preferably 20 parts by mass or less with respect to 100 parts by mass in total of Component A-1 and Component A-2.

[0074] Regarding the content of Component D in the composition of the present invention, from the viewpoint 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 still more preferably 1.0% 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 10% by mass or less, more preferably 5% by mass or less, and still more preferably 3% by mass or less.

[0075] 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" of Mitsubishi Chemical Corporation, "Paraloid K series" of Dow Chemical Company, and "Kaneka Ace PA series" of Kaneka Corporation.

[0076] Component E in the composition of the present invention is a polyphenylene ether resin. Component E is miscible with polymer block a and polymer block c containing structural units derived from aromatic vinyl compounds of components A-1 and A-2, 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.

[0077] 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.

[0078] 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 tube, 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.

[0079] 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 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 the glass transition temperature described in the examples.

[0080] 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-1, component A-2, and 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 of component E with respect to 100 parts by mass in total of component A-1 and component A-2. 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 in total of component A-1 and component A-2.

[0081] 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.

[0082] 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 Remalloy series, and the Bestran series manufactured by Polyplastics·Evonik Corporation.

[0083] The filler of component F can be expected to improve 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.

[0084] 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.

[0085] From the viewpoint of gas barrier properties, the shape of Component F is preferably a filler having a large plate surface area relative to the particle size, such as a flat plate shape or a flaky shape. More specifically, from the viewpoint 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 viewpoint of compression set resistance, it is 50 or less, more preferably 40 or less. In the present specification, the aspect ratio can be measured by the aspect ratio measurement method described in the examples.

[0086] It is preferable to define the volume-based median diameter (D50) and the aspect ratio of the filler of Component F of the present invention within specific ranges. It is widely known that plate-like 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 at a high temperature (70 °C in the present invention), a constant strain compression force is applied to a thermoplastic elastomer molded body for several tens of hours, causing displacement (creep) due to stress loading of thermoplastic elastomer molecules such as Component A, and immediately after releasing the constant strain compression force, it is used as an index to measure whether the displacement (creep) is recovered or the displacement (creep) has occurred by measuring whether the shape is immediately restored. 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 because stress concentrates due to the compressive force, especially at the interface of the particularly hard inorganic filler in the thermoplastic elastomer composition. In addition, the deviation (creep) of the thermoplastic elastomer molecules generated at the filler interface is considered to be in a state where it is difficult to recover immediately after releasing the constant strain compressive force because it becomes a resistance to creep recovery at the interface of the inorganic filler. The inventor of the present invention has 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.

[0087] Regarding the particle diameter 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 described in the examples.

[0088] When the composition of the present invention contains component F, from the viewpoint of gas barrier properties, the ratio of component A-1, component A-2, and 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 of component F with respect to 100 parts by mass in total of component A-1 and component A-2. On the other hand, from the viewpoint of flexibility, 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 in total of component A-1 and component A-2.

[0089] When the composition of the present invention contains component F, from the viewpoint of gas barrier properties, 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. 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.

[0090] 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.

[0091] The composition of the present invention may, if necessary, contain organic fillers (e.g., wood powder, cellulose powder, 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, triamine-based, anilide-based, and benzophenone-based), heat stabilizers, anti-aging agents, 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, aluminate, lubricants (e.g., fatty acids, higher alcohols, aliphatic amides, and aliphatic esters), flame retardants, foaming agents, silicone compounds, and other various additives within a range that does not impair the effects of the present invention.

[0092] In the thermoplastic elastomer composition for tubes of the present invention, from the viewpoint of adjusting the flexibility, gas barrier properties, creep resistance, and extrusion moldability targeted by the present invention, the total amount of component A-1, component A-2, component B, component C, and component F 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.

[0093] The thermoplastic elastomer composition for tubes of the present invention is obtained by mixing raw materials containing Component A-1, Component A-2, Component B, Component C, and Component F, and further, Component E and / or Component D, and various additives as required, and solidifying by cooling.

[0094] The "mixing" referred to in the present invention is not particularly limited as long as various components are well mixed. 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, it is preferable that the mixing of the raw materials is carried out under conditions where the raw materials other than Component F are melted.

[0095] When heat melting and kneading, a general extruder can be used. For improving the kneading state, it is preferable to use a multi-screw extruder having two or more screws. The supply to the extruder may be such that various components previously mixed using a mixing device such as a Henschel mixer are fed from one hopper, or each component may be charged into two hoppers and fed while being metered by a screw or the like under the hopper.

[0096] 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, extruded into strands, and cut into pellets such as cylindrical or rice grain shapes by a cutter while being cooled in cold water.

[0097] The thermoplastic elastomer composition for tubes of the present invention can be made into a tube as a thermoplastic elastomer molded body by various known molding methods, for example, various molding methods such as extrusion molding, press molding, injection molding, calender molding, blow molding, and foam molding. Therefore, one of the preferable uses of the thermoplastic elastomer composition for tubes of the present invention is extrusion molding because, needless to say, injection molding in which the mold surface is transferred, but also because it has excellent extrusion moldability of the extrusion molded body even without mold surface transfer. Furthermore, in addition to tubes, molded bodies such as sheets and pellets can also be secondary processed by thermoforming or the like again.

[0098] The A hardness of the thermoplastic elastomer composition for tubes 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. Also, 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.

[0099] The melt mass flow rate of the thermoplastic elastomer composition for tubes 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.

[0100] The thermoplastic elastomer composition for tubes of the present invention can obtain a tube having resistance to compression (also referred to as compression set) or expansion (tension) stress (also referred to as tensile permanent elongation), that is, creep resistance. In particular, a tube having creep resistance at high temperatures, for example, at 70 °C can be obtained. Therefore, the thermoplastic elastomer composition for tubes of the present invention can be particularly preferably used for tube parts that require flexibility for transporting liquids that can reach high temperatures. Also, not limited to high temperatures, a tube having longer-term creep resistance can be obtained even in a temperature range around room temperature.

[0101] Examples of the performance evaluation items required for such liquid transport tubes include permanent distortion (creep resistance), excellent extrusion moldability with smoothness, gas barrier performance, ozone resistance, and the like.

[0102] Permanent distortion (creep resistance) refers to the durability against long-term compressive and tensile stresses. It is a pressure-compression distortion 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 does not break after long-term creep.

[0103] The excellent extrusion moldability with smoothness is a surface property for preventing the growth of air bubbles starting from minute irregularities on the inner surface of the tube to prevent liquid blockage. Especially when not used for a long time, gas accumulations may form inside the tube, and the content liquid may be blocked. Therefore, it is preferable that the surface of the tube is smoother.

[0104] Gas barrier performance is more important for tubes with a larger surface area per inner diameter compared to hoses, and it is a performance required to prevent oxidative degradation of the content liquid components and liquid blockage due to air bubbles.

[0105] Ozone resistance is the long-term physical property stability against the degradation of physical properties by ozone in the atmosphere, and further, it is 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

[0106] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The various physical properties of the raw materials used in the examples and the like were measured by the following methods.

[0107] <Component A-1 and Component A-2: 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: Two columns of "K-805L (8.0×300 mm)" and "K-804L (8.0×300 mm)" manufactured by Showa Denko K.K. were 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.

[0108] 〔Composition of block copolymer〕 Proton NMR measurement was performed using a nuclear magnetic resonance apparatus (DPX-400 manufactured by BRUKER, Germany). For example, the content of structural units derived from styrene and / or styrene derivatives was determined by quantifying the characteristic groups of styrene. The content of structural units derived from other monomer units, such as aromatic vinyl compounds and conjugated diene compounds, can also be determined by proton NMR measurement

[0109] 〔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

[0110] <Component B: Olefin polymer> 〔Melt mass flow rate (MFR)〕 Measured under the conditions of 230 °C and a load of 21 N by a method in accordance with JIS K6921-2

[0111] 〔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.

[0112] 〔Melting point〕 The melting point was measured according to ISO11357-3 using a differential scanning calorimeter. The melting peak temperature was measured at a heating rate of 10 °C / min under a nitrogen atmosphere.

[0113] <Component C: Softening agent> 〔Kinematic viscosity〕 It was measured at temperatures of 100 °C and 40 °C using a Brookfield type rotational viscometer according to JIS K 7117-1.

[0114] 〔Hydrogenation rate〕 The hydrogenation rate in the hydrogenated product of polybutene as a softening agent was determined by the area ratio of the signal intensities of the signals attributed to saturated carbon bonds and unsaturated carbon bonds when measured by proton NMR. Hereinafter, this ratio is also referred to as the saturated / unsaturated signal.

[0115] 〔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-1. For the number average molecular weight, the number average molecular weight in terms of polystyrene was also determined by the same method as that of Component A-1.

[0116] <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-1.

[0117] 〔MMA / n-BA ratio〕 The MMA / n-BA ratio was determined as follows. It was quantified by the identification by mass and the detected peak ratio obtained by pyrolysis gas chromatography / mass spectrometry (GC / MS). Mass spectrometer: JMS-T100GC manufactured by JEOL Ltd. 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

[0118] <Polyphenylene ether resin of component E> [Reduced viscosity] The reduced viscosity of component E was defined as the viscosity at 30 °C of a solution dissolved at a concentration of 0.5 g / dL in chloroform by a method compliant with JIS K 7367.

[0119] [Glass transition temperature] The glass transition temperature of component E was measured at the midpoint temperature in a nitrogen atmosphere at a heating rate of 10 °C / min using a differential scanning calorimeter in accordance with ISO11357-2.

[0120] <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-Tech Fielding was used. [Sample preparation] Conductive carbon double-sided tape was attached to an aluminum sample stage for the electron microscope, and after the target filler powder was thinly spread in a tape shape, the excess filler powder was removed by air blowing. [Measurement] The sample stage with the sample was installed in the electron microscope device, and at an acceleration voltage of 10 kV, appropriate numbers of magnified photographs with different magnification ratios and positions were taken according to the particle size and aspect ratio (length and thickness) of each filler sample. Thirty arbitrary non-agglomerated 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 Corporation) were used.

[0121] [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 a "Master Sizer 2000" manufactured by Malvern, and the 50% value in the volume-based cumulative fraction was taken as the volume-based median diameter.

[0122] <Thermoplastic Elastomer Composition for Tubes> 〔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%.

[0123] 〔Melt Mass Flow Rate (MFR)〕 The measurement was carried out in accordance with JIS K 7210-1 under the test conditions of 230°C and a load of 49 N.

[0124] Examples 1 to 10, 21 to 27, Comparative Examples 1 to 7 and 21 (1) Preparation of Thermoplastic Elastomer Composition for Tubes (Pellets) The components shown in Tables 1 to 5 and, with respect to 100 parts by mass of Component A, 0.5 part by mass of a hindered phenol-based antioxidant (Irganox 1010 manufactured by BASF) and 0.5 part by mass of a phosphorus-based antioxidant (Irgafos 168 manufactured by BASF) were charged all at once into a Super Mixer SMV-20Ba manufactured by Kawata, heated and mixed at 60°C to 80°C, and the obtained raw material powder 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 cooled in cold water and cut by a cutter to a diameter of about 3 mm and a thickness of about 3 mm to obtain pellets.

[0125] <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 that 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

[0126] (2) Preparation of a 2-mm-thick sheet The pellets were injection-molded under the following conditions to prepare a sheet with a width of 125 mm × a length of 125 mm × a thickness of 2 mm.

[0127] <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

[0128] The details of the typical components used in the examples, comparative examples, etc. are summarized below.

[0129] Component A-1: Styrene-ethylene·butylene-styrene block copolymer (SEBS) (manufactured by Kraton Corporation, Kraton G1641, weight-average molecular weight (Mw): 240,000, styrene content: 33 mass%, 1,2-vinyl bond content: 67 mass%) Component A-2: Styrene-isobutylene-styrene block copolymer (SIBS) (manufactured by Kaneka Corporation, SIBSTAR 103T-UC, weight-average molecular weight (Mw): 120,000, styrene content: 30 mass%, 1,2-vinyl bond content: none) Component A-3: Crosslinked polyisobutylene (manufactured by Kaneka Corporation, SIBSTAR P1140B (isobutylene block polymer content 66 mass%), weight-average molecular weight (Mw) cannot be measured due to crosslinking.) Note that Component A-3 does not correspond to either Component A-1 or Component A-2 and is a component for comparison with these components.

[0130] 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)

[0131] Component C-1: Hydrogenated polybutene (manufactured by NOF Corporation, Pearl Rim 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 mm 2 / s, saturation / unsaturation signal: 99.65 / 0.35, weight average molecular weight: 3,107, number average molecular weight: 1,400) Component C-3: 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)

[0132] 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)

[0133] Using the thermoplastic elastomer compositions for tubes obtained in the examples and comparative examples, the following evaluations were conducted. The results are shown in Tables 1 to 5.

[0134] 〔Oxygen Permeability Coefficient〕 A sheet with a thickness of 2 mm was cut into pieces with a width of 25 mm and a length of 30 mm. Using a press mold with a thickness of 0.5 mm, a width of 100 mm, and 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 press was performed 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 those with a permeation area of 38.5 cm 2 were used. Measurement was carried out at 23 °C using a gas permeability measuring device "BR-3" manufactured by Toyo Seiki Seisakusho in accordance with the method specified in JIS K 7126.

[0135] [Compression set rate] A circular sheet with a diameter of 29 mm and a thickness of 2 mm was produced from a sheet with a thickness of 2 mm 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 (manufactured by Toho Machinery Co., Ltd., hydraulic molding machine TB-50-2 type) heated to 200 °C, and then cooling press was performed for 5 minutes to produce a cylindrical test piece with a thickness of 12.5 mm and a diameter of 29 mm. The compression set rate (CS) was measured under the conditions of a compression rate of 25%, a temperature of 70 °C, and an environment of 24 hours in accordance with the method specified in JIS K 6262.

[0136] [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 touched with a finger by a panelist to evaluate the extrudability (unevenness). The evaluation was carried out by sensory evaluation (relative evaluation) based on the following criteria. ◎: The tube surface was smooth and there were no 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.

[0137] 〔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 (device: 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. After standing at a temperature of 23°C and a humidity of 50% RH for 40 hours, the appearance change, stickiness, and bleed of the sheet were confirmed. ◎: As felt by the panelist, there was no stickiness or bleed on the surface. ○: As felt by the panelist, stickiness was felt on the surface. △: There was a slight amount of bleed. ×: There was significant bleed and stickiness.

[0138]

Table 1

[0139] In Examples 1 - 4, Comparative Examples 1 - 2, and Comparative Example 21, the mass ratio of Component A - 1 to Component A - 2 ([A - 1] / [A - 2]) was examined. In Examples 1 - 4, the above mass ratio was in the range of 60 / 40 - 80 / 20, and it was excellent in all of gas barrier property, compression set property, and extrusion moldability. On the other hand, in Comparative Examples 1 - 2, the above mass ratio was outside the range of 50 / 50 - 85 / 15. In Comparative Example 1 with less Component A - 1, the compression set property and extrusion moldability were lower than those of the above examples. In Comparative Example 2 with more Component A - 1, the gas barrier property was inferior. In Comparative Example 21 where Component A - 3, which is the comparative component of Component A - 2, was used instead of Component A - 2, since Component A - 3 was cross - linked, the melt viscosity was high and the lumps were difficult to disperse, so it was inferior in terms of extrusion moldability. Thus, even when Component A - 3 was used instead of Component A - 2, the same effects as in the examples were not exhibited.

[0140]

Table 2

[0141] In Examples 5 to 6 and Comparative Examples 3 to 4, experiments were conducted with the softening agent component changed to paraffin oil. As a result, the same results as in Examples 1 to 4 and Comparative Examples 1 to 2 were obtained.

[0142]

Table 3

[0143] In Examples 7 to 10, experiments were conducted by using an additional 30 parts by mass of PPE resin compared to Example 1. As a result, the effect of further improving the gas barrier property due to the use of PPE resin was further confirmed. In addition, the extrusion moldability was further improved in Examples 8 to 10. On the other hand, in Comparative Examples 5 and 6, the compression set was inferior, and in Comparative Example 7, the gas barrier property was inferior.

[0144]

Table 4

[0145] In Examples 21 to 24, in Example 1, a plurality of softening agents were used and their usage ratios were examined. As a result, it was found that even when polybutene and paraffin oil were used in combination, good properties could be ensured. Furthermore, the extrusion moldability was further improved in Examples 22 to 24.

[0146]

Table 5

[0147] In Examples 25 to 27, in Example 9, a plurality of softening agents were used and their usage ratios were examined. As a result, it was found that, similar to Examples 21 to 24, even when polybutene and paraffin oil were used in combination, good properties could be ensured. Furthermore, the gas barrier property was also further improved in Examples 25 to 27.

[0148] In summary, it was shown from the above examples and the like that the tube produced using the composition of the present invention is excellent in protecting the content liquid (storage stability) and has excellent performance in preventing the blockage of the flow of the content liquid.

Industrial Applicability

[0149] The thermoplastic elastomer composition for a tube of the present invention can be used for tubes used in the fields of electric and electronic products, vehicle fields, packaging fields, and medical fields. In particular, it can be suitably used for tube parts that require flexibility for liquid transportation.

Claims

1. Component A-1: 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, wherein the hydrogenation rate of the polymer block b is 80% or more. Component A-2: A block copolymer containing a polymer block c containing a structural unit derived from an aromatic vinyl compound and a polymer block d containing a structural unit derived from isobutylene. Component B: An olefin polymer. Component C: A softening agent, and Component F: A filler are contained, the mass ratio of Component A-1 to Component A-2 ([A-1] / [A-2]) is 50 / 50 or more and 85 / 15 or less, Based on 100 parts by mass of the total of Component A-1 and Component A-2, 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 300 parts by mass or less, and the content of Component F is 10 parts by mass or more and 300 parts by mass or less. A thermoplastic elastomer composition for tubes.

2. The thermoplastic elastomer composition for tubes according to Claim 1, wherein Component C contains at least one softening agent selected from the group consisting of polybutene and paraffin oil.

3. Furthermore, the thermoplastic elastomer composition for tubes according to Claim 1 or 2 contains 1 part by mass or more and 120 parts by mass or less of the following Component E based on 100 parts by mass of the total of Component A-1 and Component A-2. Component E: A polyphenylene ether resin

4. A tube formed by extrusion molding the thermoplastic elastomer composition for tubes according to Claim 1 or 2.

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