Thermoplastic elastomer composition and extrusion molded article

Abstract

To provide a molded article having excellent gas barrier properties and compression set properties, and excellent mechanical strength, and to provide a thermoplastic elastomer composition capable of obtaining such a molded article.SOLUTION: A thermoplastic elastomer composition contains: a component A 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, in which the hydrogenation rate of the polymer block b is 80% or more; a component B that is an olefin polymer; a component C that is a softening agent; and a component F that is a filler having a volumetric median diameter of 1-100 μm and an aspect ratio of 15-50; wherein the content of the component B is 1 to 50 parts by mass, the content of the component C is 50 to 500 parts by mass, and the content of the component F is 30 to 300 parts by mass, 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. Further, the present invention relates to a molded article obtained by extrusion molding the composition, that is, an extruded molded article.

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 the thermoplastic elastomer containing an isobutylene block is excellent in gas barrier properties, it has problems of poor compression set, that is, heat resistance and mechanical strength.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, the problems of the present invention relate to providing a molded article excellent in both gas barrier properties and compression set properties, and mechanical strength (tensile strength), and providing a thermoplastic elastomer composition capable of obtaining such a molded article.

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, wherein the structural unit derived from the aromatic vinyl compound in Component A is 10% by mass or more and 65% by mass or less, and the hydrogenation rate of the polymer block b is 80% or more. Component B: An olefin polymer Component C: A softening agent, and Component F: A filler having a volume-based median diameter (D50) of 1 μm or more and 100 μm or less and an aspect ratio of 15 or more and 50 or less 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 50 parts by mass or more and 500 parts by mass or less, and the content of Component F is 30 parts by mass or more and 300 parts by mass or less. [2] Further, the thermoplastic elastomer composition according to [1] above, containing 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 Component A. Component E: A polyphenylene ether resin [3] The thermoplastic elastomer composition according to [1] or [2] above, wherein Component C is 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. [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 molded article excellent in both gas barrier properties and compression set properties and having excellent mechanical strength, and a thermoplastic elastomer composition capable of obtaining such a molded article.

Mode for Carrying Out the Invention

[0007] The thermoplastic elastomer composition of the present invention is a composition containing components A, B, C, and F 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 a structural unit derived from an aromatic vinyl compound. 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 as long as the effects of the present invention are not impaired. Examples of such a compound include ethylene, acrylonitrile, acrylic ester, vinyl acetate, etc.

[0011] 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.

[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, from the viewpoint of flexibility, it is 65% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less. In the present specification, the content of the structural unit derived from the aromatic vinyl compound can be measured by the method for measuring 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 within a range not impairing the effects of the invention. 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 the present specification, the content of the structural unit derived from the conjugated diene compound can be measured by the method for measuring 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 a 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 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 linking 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 linking form represented by A-(B - A)-A. Even more preferably, it is in the linking 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, each polymer block a and polymer block 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 80% or more, more preferably 85% or more, even more preferably 90% or more, and even more preferably 95% or more. In the present invention, the hydrogenation rate of polymer block b is determined by the proton NMR measurement method 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 terminal, 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. Note that, as long as the effects of the present invention are not impaired, generally available SIBSTAR series products manufactured by Kaneka Corporation 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 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 measuring method of the content of 1,2-vinyl bond units in the polymer block b 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, Hyper series manufactured by Kuraray Co., Ltd., and the like.

[0027] Component B in the composition of the present invention is an olefin-based 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 applies 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 caused by poor kneading. Furthermore, when Component B is miscible 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 α-olefin copolymer. 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., the Prime Polypro series manufactured by Prime Polymer Co., Ltd., and the like.

[0035] Component C in the composition of the present invention is a softening agent. The softening agent is not particularly limited as long as it is a softening agent known in the field of the present invention. For example, paraffin oil, polybutene and / or a hydrogenated product of the polybutene can be mentioned. Component C, polybutene of the present invention, is also widely known as polyisobutylene. Component C has the effects of improving flexibility, moldability, gas barrier property and permanent strain in the composition of the present invention, and from the viewpoint of ozone resistance, a hydrogenated product of polybutene is preferred. 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 from the viewpoint of improving gas barrier properties. 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 this 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, from the viewpoint of improving gas barrier properties, the kinematic viscosity of Component C at 100°C is preferably 100 mm 2 / s or more, more preferably 150 mm 2 / s or more, still 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 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, 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] 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, even 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 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, even more preferably 1,000 mm 2 / s or less, still more preferably 600 mm 2 / s or less. When Component C is paraffin oil, the kinematic viscosity at 40°C is preferably 30 mm 280 mm / s or more, more preferably 80 mm / s or more 2 150 mm / s or more, still more preferably 150 mm / s or more 2 / s or more. On the other hand, from the viewpoint of compression set, it is preferably 1,000 mm 2 / s or less, more preferably 800 mm 2 / s or less, still 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.

[0038] Ozone in the atmosphere makes it easier for the unsaturated bond portions in polybutene and / or the hydrogenated product of the polybutene to be depolymerized. As a result, cracks may occur on the surface of the molded body of the composition of the present invention, the creep resistance may deteriorate, bleeding may easily occur, and performance degradation such as stickiness may occur. The polybutene of the present invention is produced by so-called cationic polymerization using butene and isobutene as main raw materials and using initiators such as boron trifluoride and aluminum chloride and water as catalysts. 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, the polybutene molecular chain is cleaved, and low molecular weight components are generated. The generated low molecular weight components bleed to the surface of the thermoplastic elastomer molded body, resulting in problems such as stickiness. Therefore, the component C polybutene of the present invention preferably has a hydrogenated product.

[0039] From the viewpoint of suppressing such performance degradation, hydrogenated polybutene is more preferable 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.

[0040] As for the ratio of component A to 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 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.

[0041] 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.

[0042] 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. As paraffin oils, 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. can be mentioned.

[0043] The filler of component F can be expected to have an effect of improving the gas barrier properties of the composition of the present invention. Therefore, the composition of the present invention contains component F. As for the aspect ratio of component F represented by the major axis / thickness, from the viewpoint of gas barrier properties, it is 15 or more, preferably 20 or more, more preferably 25 or more. From the viewpoints of compression set resistance and strength, it is 50 or less, preferably 40 or less, more preferably 35 or less.

[0044] The filler of Component F of the present invention has a volume-based median diameter (D50) and an aspect ratio defined within a specific range. It is widely known that plate-like or scaly inorganic fillers are superior in gas barrier properties compared to organic materials such as Component A and Component B of the present invention. However, regarding the influence of the volume-based median diameter (D50), particularly the aspect ratio, on compression set resistance, nothing is known. Compression set resistance is measured by holding a constant-strain compressive force on a thermoplastic elastomer molded body for several tens of hours in an environment at a high temperature (70°C in the present invention), causing displacement (creep) due to stress loading of thermoplastic elastomer molecules such as Component A, and then measuring whether the shape immediately recovers after releasing the constant-strain compressive force. It is used as an indicator to show the degree to which the displacement (creep) recovers or the displacement (creep) has occurred. This displacement (creep) phenomenon is considered to be in a state where displacement (creep) is more likely to occur at the filler interface than in the matrix part because stress due to the compressive force concentrates at the interface of particularly hard inorganic fillers in the thermoplastic elastomer composition. Also, the displacement (creep) of thermoplastic elastomer molecules that occurs at the filler interface becomes a resistance to displacement (creep) recovery at the interface of the inorganic filler after releasing the constant-strain compressive force and is considered to be in a state where it is difficult to recover immediately. 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, the aspect ratio of Component F of the present invention is defined with an upper limit in consideration of the adverse effect on compression set resistance and a lower limit in order to obtain the effect of improving gas barrier properties. In this specification, the aspect ratio can be measured by the aspect ratio measurement method described in the examples.

[0045] From the perspective of gas barrier properties, as the shape of Component F, those with a large plate surface area relative to the particle size, for example, flat plate-like or scaly fillers, are preferred.

[0046] The volume-based median diameter (D50) of Component F is 1 μm or more and 100 μm or less, and from the viewpoint of gas barrier properties, it is preferably 2 μm or more, more preferably 5 μm or more. On the other hand, from the viewpoint of compression set resistance, it is preferably 50 μm or less, more preferably 20 μm or less. In this specification, the volume-based median diameter (D50) of Component F can be measured by the measurement method of the volume-based median diameter described in the examples.

[0047] 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.

[0048] The ratio of Component A to Component F is 30 parts by mass or more and 300 parts by mass or less with respect to 100 parts by mass of Component A. From the viewpoint of gas barrier properties, Component F is preferably 50 parts by mass or more, more preferably 80 parts by mass or more with respect to 100 parts by mass of Component A. On the other hand, from the viewpoints of strength and flexibility, Component F is preferably 250 parts by mass or less, more preferably 200 parts by mass or less with respect to 100 parts by mass of Component A.

[0049] 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.

[0050] Component F can be produced by a conventionally known method. Component F is available as a commercially available product. Examples of commercially available products include the fine powder talc series and general-purpose talc series manufactured by Nippon Talc Co., Ltd., P talc and the Hi-Tron series manufactured by Takehara Chemical Industry Co., Ltd.

[0051] 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 component D is a polar polymer, it has a high molecular cohesive force, and due to its high molecular weight, when the composition of the present invention contains component D, it has the effect of increasing the melt viscosity and further the melt tension during melt kneading or extrusion molding of the composition of the present invention.

[0052] As a result, it is expected to have the effect of improving the extrusion moldability by crushing the 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 extrusion molding of the composition of the present invention are adjusted to impart formability during extrusion molding, improve the extrusion moldability, and further, it is presumed that component A is immiscible at room temperature and forms a unique dispersed phase in the molded body. As a result, acrylic molecules with high cohesive force can also be expected to have the effect of improving the creep resistance of the composition of the present invention.

[0053] Component D is not particularly limited except that it is an acrylic polymer containing structural units derived from (meth)acrylic acid esters, but 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.

[0054] Here, "(meth)acrylic" means acrylic and / or methacrylic. "(meth)acrylic acid ester" means acrylic acid ester and / or methacrylic acid ester. Also, "acrylic acid alkyl" and "methacrylic acid alkyl" mean alkyl esters of acrylic acid and alkyl esters of methacrylic acid, respectively.

[0055] As the alkyl group, an alkyl group having 1 to 10 carbon atoms is preferable, and an alkyl group having 1 to 4 carbon atoms is more preferable. 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 methacrylic acid ester, from the viewpoint of increasing the melt viscosity, methyl methacrylate (MMA) is preferable. As the acrylic acid ester, from the viewpoint of affinity with component A of the present invention, normal butyl acrylate (n-BA), isobutyl acrylate (i-BA), and 2-ethylhexyl acrylate (HA) are preferable.

[0056] As the alkyl methacrylate-acrylic acid alkyl 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, the ratio of the alkyl methacrylate to the acrylic acid alkyl is preferably 95 to 55% by mass and 45 to 10% by mass, respectively, more preferably 90 to 60% by mass and 40 to 10% by mass, respectively, and even more preferably 88 to 80% by mass and 12 to 20% by mass, respectively. 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 consideration of the copolymerizability of the alkyl methacrylate and normal butyl acrylate, since a small block of normal butyl acrylate is naturally generated, such a block may be present in the alkyl methacrylate-acrylic acid alkyl copolymer. In this specification, the ratio of the alkyl methacrylate to the acrylic acid alkyl can be measured by the measurement method of thermal decomposition gas chromatography / mass spectrometry described in the examples.

[0057] Component D may further contain at least one other vinyl monomer copolymerizable with a (meth)acrylate ester as a constituent unit. Here, from the viewpoint of creep resistance, the proportion 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 proportion 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.

[0058] 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, a non-crosslinked linear structure and a branched structure are preferred. More preferably, from the viewpoint of increasing the melt viscosity, it is a linear structure.

[0059] Regarding the molecular weight of component D, from the viewpoint of creep resistance, the weight average molecular weight is 400,000 or more, preferably 700,000 or more, 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, still more preferably 5,000,000 or less. In this specification, the weight average molecular weight can be measured by the measurement method of the weight average molecular weight described in the examples.

[0060] When the composition of the present invention contains component D, the ratio of component A to component D in the composition of the present invention is preferably 1 part by mass or more, more preferably 2 parts by mass or more, still more preferably 4 parts by mass or more of component D with respect to 100 parts by mass of component A from the viewpoints of improving the extrusion moldability and creep resistance of the composition of the present invention. 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, still more preferably 20 parts by mass or less with respect to 100 parts by mass of component A.

[0061] When the composition of the present invention contains component D, the content of component D in the composition of the present invention is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1.0% by mass or more from the viewpoint of improving the extrusion moldability and creep resistance of the composition of the present invention. 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, still more preferably 3% by mass or less.

[0062] 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.

[0063] Component E in the composition of the present invention is a polyphenylene ether resin. Component E is miscible with the polymer block a containing the structural unit 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.

[0064] 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.

[0065] From the perspective of miscibility, the reduced viscosity of component E is preferably 0.1 dL / g or more, and from the perspectives of dispersibility and the surface properties of the molded body, it is preferably 0.45 dL / g or less. From these perspectives, 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.

[0066] From the perspective of resistance to compression set, the glass transition temperature of component E is preferably 170°C or more, and from the perspective of thermal deterioration during the production of the composition, it is preferably 260°C or less. From these perspectives, the glass transition temperature of component E is preferably 170 to 260°C, more preferably 180 to 250°C, and still 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.

[0067] When the composition of the present invention contains component E, from the perspective of improving the resistance to compression set 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 still 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 120 parts by mass or less, more preferably 100 parts by mass or less, still more preferably 80 parts by mass or less, and still more preferably 70 parts by mass or less with respect to 100 parts by mass of component A.

[0068] When the composition of the present invention contains component E, from the perspective of improving the resistance to compression set of the composition of the present invention, 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 still more preferably 10% by mass or more. 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 still more preferably 15% by mass or less.

[0069] Component E can be produced by a conventionally known method. Component E is commercially available. Examples of commercially available products include the Zylon series manufactured by Asahi Kasei Corporation, the Noryl series manufactured by SABIC, the Upias series manufactured by Global Polyacetal, the Remaloy series, and the Bestran series manufactured by Polyplastics Evonik.

[0070] The composition of the present invention may, if necessary and within a range that does not impair the effects of the present invention, contain organic fillers (e.g., wood powder and 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.

[0071] In the thermoplastic elastomer composition of the present invention, the total amount of component A, component B, component C, and component F is preferably 40% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, from the viewpoint of adjusting the flexibility, gas barrier property, creep resistance, and extrusion moldability aimed at by the present invention. The upper limit value of the total amount is 100% by mass, but preferably 95% by mass or less, more preferably 90% by mass or less.

[0072] The thermoplastic elastomer composition of the present invention is obtained by mixing raw materials containing component A, component B, component C, and component F, and further, if necessary, component D and / or component E, and furthermore various additives, etc., and solidifying by cooling.

[0073] As used in the present invention, "mixing" is not particularly limited as long as various components are well mixed. Various components may be dissolved in an organic solvent capable of dissolving them and then mixed, or they may be mixed by heat melting and kneading. However, it is preferable to carry out the mixing of raw materials under conditions where raw materials other than component F are melted.

[0074] 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.

[0075] 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.

[0076] The thermoplastic elastomer composition of the present invention can be made into 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 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 extrusion moldability of the extruded molded body. Furthermore, molded bodies such as sheets and pellets can be secondary processed by thermoforming or the like again.

[0077] 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. 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.

[0078] The flexural stress of the thermoplastic elastomer composition of the present invention is preferably 0.15 MPa or more, more preferably 0.20 MPa or more, and still more preferably 0.25 MPa or more, from the viewpoint of kinking when formed into, for example, a tube. From the viewpoint of ease of bending when formed into a tube, it is preferably 0.6 MPa or less, more preferably 0.5 MPa or less, and still more preferably 0.45 MPa or less.

[0079] The tensile strength of the thermoplastic elastomer composition of the present invention is preferably 1.0 MPa or more, more preferably 2.0 MPa or more, and still more preferably 2.5 MPa or more, from the viewpoint that generally, the higher the tensile strength, the higher the material strength and the higher the reliability during use.

[0080] The thermoplastic elastomer composition of the present invention can obtain a molded article having resistance (also referred to as tensile permanent elongation) to compression (also referred to as compression set) or expansion (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 further long-term creep resistance can be obtained.

[0081] Examples of the performance evaluation items required for such a liquid transport tube include permanent distortion (creep resistance), gas barrier performance, ozone resistance, and the like.

[0082] Permanent distortion (creep resistance) refers to the durability against long-term compression or expansion (tensile) stress. It is a compression set 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 having a larger diameter than the inner diameter of the tube, it is more preferable to have a tensile creep performance that does not break even after long-term creep.

[0083] The excellent extrusion formability in terms of smoothness refers to the surface property that bubbles grow starting from minute irregularities on the inner surface of the tube to prevent liquid blockage. Particularly when not in use for a long period, gas accumulation may occur inside the tube, causing the content liquid to become blocked. Therefore, it is preferable that the surface of the molded body is smoother.

[0084] 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 bubbles.

[0085] Ozone resistance is the long-term physical property stability against degradation of physical properties caused 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.

[0086] Bending stress is an index indicating the self-supporting property of the tube and the blockage of the tube due to kinks (bends). For tubes used as mechanical parts, an appropriate bending stress is required so that they do not sag due to their own weight or the weight of the content liquid and the inner diameter is not blocked by bending.

Examples

[0087] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples. The various physical properties of the raw materials used in the examples and the like were measured by the following methods.

[0088] <Component A: Block copolymer> 〔Weight average molecular weight (Mw)〕 The weight average molecular weight (Mw) was determined as 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: RI (differential refractometer) detector, L-3300 manufactured by Hitachi · 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.

[0089] 〔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 other monomer units can also be determined by proton NMR measurement.

[0090] 〔Content of 1,2-vinyl bond units in polymer block b〕 The block copolymer before hydrogenation was dissolved in CDCl3 and the proton spectrum was measured (apparatus: JNM-Lambda 500 (manufactured by JEOL Ltd., Japan), measurement temperature: 50 °C). The content of 1,2-vinyl bond units was calculated from the ratio of the total peak area of the conjugated diene compound units to the peak area corresponding to the 1,2-vinyl bond units in the conjugated diene compound units.

[0091] 〔Hydrogenation rate〕 The hydrogenation rate of polymer block b was determined by measuring the content of carbon-carbon double bonds derived from the conjugated diene compound in the block copolymer before and after hydrogenation using a proton NMR spectrum.

[0092] <Component B: Olefin polymer> 〔Melt mass flow rate (MFR)〕 It was measured at 230 °C under a load of 21 N by a method conforming to JIS K6921-2.

[0093] 〔Flexural modulus〕 A test piece with a length of 80 mm × width of 10 mm × thickness of 4 mm was measured by a three-point bending test at a speed of 2 mm / min by a method conforming to JIS K7171.

[0094] 〔Melting point〕 The melting point was measured in accordance with ISO11357-3 using a differential scanning calorimeter. The melting peak temperature was measured under a nitrogen atmosphere at a heating rate of 10 °C / min.

[0095] <Component C: Plasticizer> 〔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.

[0096] 〔Hydrogenation rate〕 When Component C is a hydrogenated product of polybutene, the hydrogenation rate was determined by the area ratio of the signal intensities of the signals attributable 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.

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

[0098] <Component D: Acrylic polymer> 〔Weight-average molecular weight (Mw)〕 It was determined in the same manner as for the block copolymer of Component A.

[0099] 〔MMA / n-BA ratio〕 The MMA / n-BA ratio was determined as follows. It was identified by mass and quantified by the detection 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

[0100] <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.

[0101] [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.

[0102] <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, 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 an electron microscope, and the target filler powder was thinly spread in a tape shape. Then, excess filler powder was removed by air blowing. [Measurement] A sample stage equipped with a sample was installed in an electron microscope apparatus. At an acceleration voltage of 10 kV, appropriate numbers of magnified images with different measurement magnifications and positions were taken according to the particle diameters and aspect ratios (length and thickness) of each filler sample. Thirty arbitrary non-aggregated particles were selected from the particles observed in the photographs, and their individual lengths and thicknesses were measured using image analysis and measurement software ("WinRooF2015" manufactured by Mitani Shosha Co., Ltd.), and the average values obtained were used.

[0103] 〔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 for 30 seconds with 70 w of ultrasonic waves was measured for its particle size distribution using "Mastersizer 2000" manufactured by Malvern Panalytical Ltd., and the 50% value in the volume-based cumulative fraction was taken as the volume-based median diameter.

[0104] <Thermoplastic elastomer composition> 〔A hardness〕 For a stack of three sheets with a thickness of 2 mm (total 6 mm), in accordance with JIS K 6253, 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%.

[0105] Examples 1 to 13 and Comparative Examples 1 to 11 (1) Preparation of thermoplastic elastomer composition (pellets) The components shown in Tables 1 to 4, and 0.5 parts by mass of a hindered phenol-based antioxidant (Irganox1010 manufactured by BASF SE) and 0.5 parts by mass of a phosphorus-based antioxidant (Irgafos168 manufactured by BASF SE) were collectively charged into a Super Mixer SMV-20Ba manufactured by Kawata Co., Ltd. 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-shaped 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.

[0106] <Melting and 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 to 180 °C, and the temperature up to the extruder outlet was set to 240 °C. Screw rotation speed: 400 r / min Extrusion die: Strand die with a diameter of 3 mm Raw material supply rate: 15 kg / h

[0107] (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.

[0108] (3) Preparation of bending test specimens The pellets were injection-molded under the following conditions to prepare rod-shaped test specimens with a width of 23.5 mm × a length of 150 mm × a thickness of 6 mm. <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

[0109] The details of the typical components used in the examples, comparative examples, etc. are summarized below.

[0110] 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%, hydrogenation rate of polymer block b: 99.6%) 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)

[0111] 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, saturated / unsaturated 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-100, kinematic viscosity at 100°C: 220 mm 2 / s, kinematic viscosity at 40°C: 9,500 mm 2 / s, saturated / unsaturated signal: 99.47 / 0.53, weight average molecular weight: 1,901, number average molecular weight: 980) Component C-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, saturated / unsaturated signal: (none), weight average molecular weight: 1,263, number average molecular weight: 1,128)

[0112] Component E: Polyphenylene ether (PPE) (manufactured by Asahi Kasei Chemicals Corporation, Zylon S202A, reduced viscosity: 0.42 dL / g, Tg: 214°C)

[0113] Component F-1: Calcium carbonate (manufactured by Maruo Calcium Co., Ltd., Super 3S, volume-based median diameter (D50): 3.4 μm, aspect ratio: 1.5, shape: powdery) Component F-2: Talc (manufactured by Nippon Talc Co., Ltd., Nano Ace D-800, volume-based median diameter (D50): 0.8 μm, aspect ratio: 20, shape: plate-like) Component F-3: Talc (manufactured by Hayashi Chemical Co., Ltd., TP-TK, volume-based median diameter (D50): 13 μm, aspect ratio: 33, shape: plate-like) Component F-4: Talc (manufactured by Nippon Talc Co., Ltd., SG-95, volume-based median diameter (D50): 2.1 μm, aspect ratio: 30, shape: plate-like) Component F-5: Mica (manufactured by Repco, M-60, volume-based median diameter (D50): 160 μm, aspect ratio: 60, shape: plate-like) Note that since Component F-1 does not correspond to the aspect ratio value and Components F-2 and F-5 do not correspond to the D50 value, they are components for comparison of Component F.

[0114] 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.

[0115] 〔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 was carried out for 3 minutes to produce a sheet-shaped 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 Seisakusho in accordance with the method specified in JIS K 7126.

[0116] 〔Compression Set Ratio〕 From a 2-mm-thick sheet, a circular sheet with a diameter of 29 mm was produced using a circular punching blade with a diameter of 29 mm. It was inserted into a cylindrical mold with a height of 12.5 mm and a diameter of 29 mm, and a hot press machine (manufactured by Toho Machinery Co., Ltd., hydraulic molding machine TB-50-2 type) heated to 200 °C was used for hot pressing for 5 minutes, and then cooling pressing was carried out for 5 minutes to produce a cylindrical test piece with a thickness of 12.5 mm and a diameter of 29 mm. In accordance with the method specified in JIS K 6262, the compression set ratio (CS) was measured under a compression ratio of 25%, a temperature of 70 °C, and an environment of 24 hours.

[0117] 〔Ozone Resistance Test〕 A sheet with a thickness of 2 mm, a width of 50 mm, and a length of 50 mm was left standing at a temperature of 23°C and a humidity of 50% RH for 40 hours in a testing machine (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 distortion. After that, 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 state with some bleeding. ×: It was in a sticky state with significant bleeding.

[0118] 〔Bending Stress Test〕 Using a rod-shaped test piece with a width of 23.5 mm × a length of 150 mm × a thickness of 6 mm and conforming to JIS K7171, and using a tensile testing machine (Autograph AG-50kND type) manufactured by Shimadzu Corporation, the bending stress (MPa) was calculated at a temperature environment of 23°C, a distance between supports of 48 mm, and a bending speed of 2 mm / min.

[0119] 〔Mechanical Strength (Tensile Strength)〕 Regarding a sheet with a thickness of 2 mm, a width of 50 mm, and a length of 50 mm, a No. 3 test piece (length 20 mm) described in JIS K7113 was produced using a die-cutting machine. Regarding this test piece, using a tensile testing machine (Autograph AG-50kND type) manufactured by Shimadzu Corporation, the test piece was pulled at a speed of 200 mm / min in a temperature environment of 23°C. The stress (MPa) at the time of test piece breakage was recorded as the tensile strength.

[0120]

Table 1

[0121] In Examples 1 - 3 and Comparative Examples 1 - 4, paraffin oil was used as a softening agent to examine the effects of various fillers. In Examples 1 and 2, filler F-4 or F-3 was added to Comparative Example 1. As a result, these fillers had little effect on compression set and the gas barrier properties were improved. Furthermore, regarding the aspect ratio of the fillers, when comparing in the order of F-1 to F-5, a tendency was observed that the gas barrier properties improved as the aspect ratio increased. On the other hand, Comparative Example 4 using filler F-5 with an aspect ratio of 60 was slightly inferior in compression set and also inferior in terms of tensile strength compared to Examples 1 and 2. Example 3 is an experiment in which the amount of filler F-5 was increased compared to Example 2. From the results of Example 3, it was found that increasing the amount of the filler had no adverse effect on compression set and the gas barrier properties were further improved. In addition, Examples 1 to 3 were also excellent in ozone resistance.

[0122]

Table 2

[0123] In Examples 4 to 5 and Comparative Examples 5 to 8, non-hydrogenated polyisobutene was used as the softening agent to examine the effects of various fillers.

[0124]

Table 3

[0125] In Examples 6 to 8 and Comparative Examples 9 to 10, hydrogenated polyisobutene was used as the softening agent to examine the effects of various fillers. When summarizing the results of Examples 4 to 7 and Comparative Examples 5 to 10, even when using non-hydrogenated polyisobutene or hydrogenated polyisobutene as the softening agent, the effects of the fillers similar to those in Examples 1 to 2 using paraffin oil as the softening agent could be confirmed. On the other hand, when filler F-5 was used in Comparative Example 8, the result was inferior tensile strength. Example 8 is an experiment in which the amount of filler F-3 is increased compared to Example 7. From the results of Example 8, it was found that even when the amount of the filler was increased, there was no adverse effect on the compression set, and the gas barrier property was further improved. On the other hand, when filler F-5 was used in Comparative Example 10, the tensile strength was inferior. In addition, Examples 6 to 7 were also excellent in ozone resistance.

[0126]

Table 4

[0127] In Examples 9 to 13 and Comparative Example 11, polyphenylene ether resin of Component E was added to examine its effect. As a result, it was confirmed that the compression set and the gas barrier property were improved as the amount of F-3 component used was increased. Examples 12 to 13 are examples in which the amount of Component E is reduced or increased compared to the amount in Comparative Example 11. Even when the amount of Component E was increased or decreased, the effect of adding the filler was confirmed. In addition, Examples 9 to 13 were also excellent in ozone resistance.

Industrial Applicability

[0128] 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, wherein the structural unit derived from the aromatic vinyl compound in Component A is 10% by mass or more and 65% by mass or less, and the hydrogenation rate of the polymer block b is 80% or more. Component B: An olefin-based polymer Component C: A softening agent, and Component F: A filler having a volume-based median diameter (D50) of 1 μm or more and 100 μm or less and an aspect ratio of 15 or more and 50 or less which is contained to form A thermoplastic elastomer composition, wherein with respect to 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 50 parts by mass or more and 500 parts by mass or less, and the content of Component F is 30 parts by mass or more and 300 parts by mass or less.

2. Furthermore, the thermoplastic elastomer composition according to Claim 1, containing 1 part by mass or more and 120 parts by mass or less of the following Component E with respect to 100 parts by mass of Component A. Component E: A polyphenylene ether resin

3. Component C is 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 is the thermoplastic elastomer composition according to claim 1 or 2.

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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