Thermoplastic elastomer composition

Abstract

To provide a thermoplastic elastomer composition that offers an excellent balance of moldability, flexibility, and heat resistance. [Solution] A thermoplastic elastomer composition comprising (A) an isobutylene-isoprene copolymer elastomer, (C) a propylene-based flexible polyolefin having a melting enthalpy of less than 50 J / g and a melt mass flow rate of 0.1 to 50 g / 10 min measured at 230°C and 21.18 N in accordance with JIS K7210-1:2014, (D) a non-aromatic rubber softener, and (E) a phenolic resin crosslinking agent. Furthermore, (B) polypropylene, (F) a crosslinking accelerator, (G) petroleum resin, etc., may also be included. The melting point of (C) the propylene-based flexible polyolefin is preferably 130°C or higher.

Description

[Technical Field]

[0001] This invention relates to thermoplastic elastomer compositions. [Background technology]

[0002] Conventionally, thermoplastic elastomer compositions obtained by melt-kneading a composition containing isobutylene-isoprene copolymer elastomer, polypropylene, and a rubber softener in the presence of a crosslinking agent such as a phenolic resin have been proposed as materials for sealing members such as medical plugs due to their excellent gas barrier properties. On the other hand, these thermoplastic elastomer compositions have the following drawbacks: (1) the isobutylene-isoprene copolymer elastomer is crosslinked by a crosslinking agent such as a phenolic resin, which tends to result in insufficient moldability; (2) if the amount of polypropylene is increased to maintain moldability, the result tends to be insufficient flexibility; and (3) if the amount of rubber softener is increased to maintain flexibility, the result is that the rubber softener bleeds out when used at high temperatures for a long time. To solve these problems, Patent Document 1 proposes using a propylene-based low-crystalline polymer. However, the thermoplastic elastomer composition described in Patent Document 1 contains a large amount of propylene-based low-crystalline polymer having properties as a wax or hot-melt adhesive, resulting in insufficient heat resistance. Therefore, when used as a material for medical plugs, it has the disadvantage of not being able to be subjected to high-pressure steam sterilization. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-080444 [Patent Document 2] Japanese Patent Publication No. 2008-056824 [Patent Document 3] Japanese Patent Publication No. 2007-231267 [Patent Document 4] Japanese Patent Application Laid-Open No. 2021-172812

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a thermoplastic elastomer composition excellent in the balance of molding processability, flexibility, and heat resistance.

Means for Solving the Problems

[0005] As a result of intensive studies, the present inventor has found that the above problems can be achieved by a specific thermoplastic elastomer composition. <000095> That is, aspects of the present invention are as follows. [1]. (A) 100 parts by mass of an isobutylene-isoprene copolymer elastomer, (B) 5 to 100 parts by mass of polypropylene, (C) 1 to 100 parts by mass of a hydrogenated product of a block copolymer of an aromatic vinyl compound and a conjugated diene compound, (D) 1 to 200 parts by mass of a non-aromatic rubber softener, and (E) 0.5 to 25 parts by mass of a phenolic resin crosslinking agent, a thermoplastic elastomer composition containing the same. [2]. The hydrogenated product of the block copolymer of the aromatic vinyl compound and the conjugated diene compound as the above component (C) has an elution peak having a peak top in the region of a polystyrene-equivalent molecular weight of 2.0 to 20×10 ,

[0006] in the differential molecular weight distribution curve measured by gel permeation chromatography, the thermoplastic elastomer composition according to item [1]. <OO00101>[3]. The hydrogenated product of the block copolymer of the aromatic vinyl compound and the conjugated diene compound as the above component (C) is the largest in the differential molecular weight distribution curve measured by (C1) gel permeation chromatography, and has a polystyrene-equivalent molecular weight of 2.0 to 20×10 4A thermoplastic elastomer composition according to item [1] or [2], comprising a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound having an elution peak with a peak top in the region. [4]. The hydrogenated block copolymer of component (C) of an aromatic vinyl compound and a conjugated diene compound is the largest in the differential molecular weight distribution curve measured by (C2) of the hydrogenated block copolymer of component (C1) of an aromatic vinyl compound and a conjugated diene compound, and has a polystyrene-equivalent molecular weight of 20 × 10⁻¹⁰. 4 The thermoplastic elastomer composition according to item [3], comprising a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound having an elution peak with a peak top in the region exceeding [3]. [5]. The thermoplastic elastomer composition according to item [4], wherein the mass ratio (amount of component (C1) / amount of component (C2)) of the hydrogenated block copolymer of component (C1) and the component (C2) is 20 / 80 to 98 / 2. [6]. The thermoplastic elastomer composition according to any one of items [1] to [5], wherein the above component (C) a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound comprises (C3) a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound having a structural unit derived from β-farnesene. [7]. A thermoplastic elastomer composition according to any one of items [1] to [6], wherein the above component (B) polypropylene comprises (B1) polypropylene having a melt mass flow rate of 0.01 to 10 g / 10 min measured in accordance with JIS K7210-1:2014 at a temperature of 230°C and a load of 21.18 N, and (B2) polypropylene having a melt mass flow rate of more than 10 g / 10 min and 100 g / 10 min or less measured in accordance with JIS K7210-1:2014 at a temperature of 230°C and a load of 21.18 N. [8]. The thermoplastic elastomer composition according to item [7], wherein the mass ratio of the amount of component (B1) polypropylene to the amount of component (B2) polypropylene (amount of component (B1) / amount of component (B2)) is 95 / 5 to 5 / 95. [9]. The thermoplastic elastomer composition described in any one of sections [1] to [8], wherein the above component (B) polypropylene contains (B3) polypropylene that satisfies the following properties (1) and (2): (1) the enthalpy of melting is less than 50 J / g, and (2) the melt mass flow rate measured in accordance with JIS K7210-1:2014 at a temperature of 230°C and a load of 21.18 N is 0.01 to 50 g / 10 min.

[10] The thermoplastic elastomer composition according to item [9], wherein the melting point of component (C) propylene-based flexible polyolefin is 130°C or higher.

[11] . The thermoplastic elastomer composition according to item [9] or

[10] , wherein the melting enthalpy of the above component (C) propylene-based flexible polyolefin is 5 to 30 J / g.

[12] . The kinematic viscosity at 40°C of the above component (D), a non-aromatic rubber softener, as measured according to JIS K2283:2000, is 1000 to 10000 mm². 2 A thermoplastic elastomer composition according to any one of items [1] to

[11] , wherein the temperature is 1 / s or higher.

[13] . Furthermore, the thermoplastic elastomer composition according to any one of items [1] to

[12] , further comprising 1 to 100 parts by mass of one or more selected from the group consisting of (G) petroleum resins, terpene resins, and rosins, per 100 parts by mass of the above component (A) isobutylene-isoprene copolymer elastomer.

[14] . An article comprising a thermoplastic elastomer composition as described in any one of items [1] to

[13] . [Effects of the Invention]

[0007] The thermoplastic elastomer composition of the present invention exhibits an excellent balance of moldability, flexibility, and heat resistance. The preferred thermoplastic elastomer composition of the present invention also has good mechanical properties and gas barrier properties. Therefore, the thermoplastic elastomer composition of the present invention can be suitably used as a material for sealing members such as plugs, gaskets, and packings used in various articles, such as medical plugs. Furthermore, in one embodiment, the thermoplastic elastomer composition of the present invention also exhibits excellent vibration damping characteristics, and can therefore be suitably used as vibration damping members and soundproofing members for automobiles, as well as for vibration damping members and soundproofing members for home appliances such as audio equipment, refrigerators, vacuum cleaners, and air conditioners. [Modes for carrying out the invention]

[0008] In this specification, the term "resin" is used to include resin mixtures containing two or more resins, as well as resin compositions containing components other than resins. The same applies to the term "elastomer."

[0009] In this specification, the term "film" is used interchangeably or interchangeably with the term "sheet." In this specification, the terms "film" and "sheet" are used for materials that can be industrially wound into rolls. The term "plate" is used for materials that cannot be industrially wound into rolls. In this specification, lamination of one layer with another includes both directly laminating those layers and laminating them with one or more other layers, such as an anchor coat, interposed between them.

[0010] In this specification, the term "greater than or equal to" in relation to a numerical range means a certain number or greater than a certain number. For example, "20% or more" means 20% or greater than 20%. The term "less than or equal to" in relation to a numerical range means a certain number or less than a certain number. For example, "20% or less" means 20% or less than 20%. The symbol "~" in relation to a numerical range means a certain number, greater than a certain number and less than another certain number, or another certain number. Here, the other certain number is a number greater than a certain number. For example, "10~90%" means 10%, greater than 10% and less than 90%, or 90%. Furthermore, the upper and lower limits of a numerical range can be combined arbitrarily, and embodiments with such arbitrary combinations should be discernible. For example, from descriptions relating to the numerical range of a certain characteristic, such as "usually 10% or more, preferably 20% or more. On the other hand, usually 40% or less, preferably 30% or less," or "usually 10-40%, preferably 20-30%," it can be inferred that, in one embodiment, the numerical range of that characteristic is 10-40%, 20-30%, 10-30%, or 20-40%.

[0011] Except in the examples, or unless otherwise specified, all numerical values ​​used herein and in the claims should be understood to be modified by the term “approximately.” Without attempting to limit the application of the doctrine of equivalents to the claims, each numerical value should be interpreted in terms of significant figures and by applying common rounding methods.

[0012] In this specification, terms used to specify shapes or geometric conditions, such as parallel, orthogonal, and perpendicular, shall include not only their strict meanings but also substantially equivalent conditions.

[0013] In this specification, when we describe a composition as "containing a certain substance," it should be understood that in one embodiment, it contains a certain substance, consists of a certain substance, or consists solely of a certain substance. For example, from the description "Composition A contains substance a1 and substance a2," it should be understood that in one embodiment, Composition A contains substance a1 and substance a2, Composition A consists of substance a1 and substance a2, or Composition A consists solely of substance a1 and substance a2.

[0014] 1. Thermoplastic elastomer composition: The thermoplastic elastomer composition of the present invention comprises (A) an isobutylene-isoprene copolymer elastomer, (B) polypropylene, (C) a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound, (D) a softening agent for non-aromatic rubbers, and (E) a phenolic resin crosslinking agent. In one preferred embodiment, the thermoplastic elastomer composition of the present invention may further contain (F) at least one or more crosslinking accelerators selected from the group consisting of zinc oxide, magnesium oxide, and stannous chloride. In another preferred embodiment, the thermoplastic elastomer composition of the present invention may further contain (G) one or more selected from the group consisting of petroleum resins, terpene resins, and rosins. The components are described below.

[0015] (A) Isobutylene / isoprene copolymer elastomer: The thermoplastic elastomer composition of the present invention comprises (A) an isobutylene-isoprene copolymer elastomer. The (A) isobutylene-isoprene copolymer elastomer enhances the flexibility, gas barrier properties, and vibration damping characteristics of the thermoplastic elastomer composition of the present invention.

[0016] (A) The isobutylene-isoprene copolymer elastomer is a low-unsaturation, rubbery, amorphous copolymer containing constituent units derived from isobutylene (2-methylpropene) and constituent units derived from isoprene (2-methyl-1,3-butadiene). (A) The isobutylene-isoprene copolymer elastomer can be obtained, for example, by polymerizing isobutylene and a small amount of isoprene in methyl chloride with anhydrous aluminum chloride as a catalyst.

[0017] (A) The content of isoprene-derived structural units in the isobutylene-isoprene copolymer elastomer may be preferably 0.5 to 15 mol%, more preferably 0.8 to 5.0 mol%, from the viewpoint of controlling the crosslink density within an appropriate range and improving mechanical properties and moldability, with the total structural units being 100 mol%.

[0018] (A) In one embodiment, the isobutylene-isoprene copolymer elastomer may contain chlorinated isobutylene-isoprene copolymer elastomers and halogenated isobutylene-isoprene copolymer elastomers such as brominated isobutylene-isoprene copolymer elastomers. In this case, the amount of halogen element added may be 5.0% by mass or less, 4.0% by mass or less, 3.0% by mass or less, 0.1 to 2.5% by mass, or 0 to 5.0% by mass, based on 100% by mass of the isobutylene-isoprene copolymer elastomer in one embodiment.

[0019] (A) The isobutylene-isoprene copolymer elastomer may contain constituent units derived from other monomers other than isobutylene and isoprene, to the extent that it does not contradict the purpose of the present invention, such as aromatic divinyl compounds such as divinylbenzene, styrene, aromatic vinyl compounds such as p-methylstyrene, and conjugated dienes other than isoprene such as 1,3-butadiene. In this case, the content of constituent units derived from other monomers may be 3.0 mol% or less, 2.5 mol% or less, 2.0 mol% or less, 1.5 mol% or less, 1.0 mol% or less, 0.1 to 0.5 mol%, or 0 to 3.0 mol%, with the total constituent units being 100 mol%, in one embodiment.

[0020] (A) The isobutylene-isoprene copolymer elastomer may include a modified product obtained by reacting it with an unsaturated compound having a functional group such as a carboxyl group, an acid anhydride group, a hydrosilyl group, an amino group, and an epoxy group, to the extent that it does not contradict the purpose of the present invention. In this case, the amount of the unsaturated compound added may be 20% by mass or less, 15% by mass or less, 10% by mass or less, 5% by mass or less, 3% by mass or less, 0.1 to 1% by mass, or 0 to 20% by mass, based on 100% by mass of the isobutylene-isoprene copolymer elastomer in one embodiment.

[0021] (A) One or more of these can be used as the isobutylene-isoprene copolymer elastomer.

[0022] The amount of (A) isobutylene-isoprene copolymer elastomer blended may be, with the total components of the thermoplastic elastomer composition as 100% by mass, preferably 40% by mass or more, more preferably 45% by mass or more, even more preferably 50% by mass or more, even more preferably 55% by mass or more, and most preferably 60% by mass or more, depending on the types of components other than (A) isobutylene-isoprene copolymer elastomer. On the other hand, the amount of (A) isobutylene-isoprene copolymer elastomer blended may be, with the total components of the thermoplastic elastomer composition as 100% by mass, preferably 45% by mass or more, even more preferably 50% by mass or more, even more preferably 55% by mass or more, and most preferably 60% by mass or more.

[0023] (B) Polypropylene: The thermoplastic elastomer composition of the present invention contains (B) polypropylene. (B) polypropylene enhances the moldability of the thermoplastic elastomer composition of the present invention.

[0024] (B) Polypropylene is a resin that mainly contains structural units derived from propylene. Here, "mainly contains structural units derived from propylene" means that the content of structural units derived from propylene is 50 to 100 mol%. In one embodiment, the content of structural units derived from propylene in (B) polypropylene may be 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, or 90 to 100 mol%, with the total structural units being 100 mol%.

[0025] (B) From the viewpoint of heat resistance, the melting point of polypropylene may be preferably 120°C or higher, more preferably 130°C or higher, even more preferably 140°C or higher, even more preferably 150°C or higher, and most preferably 160°C or higher. (B) From the viewpoint of heat resistance, a higher melting point is preferable for polypropylene. However, since it is polypropylene, the melting point will probably be around 167°C at most.

[0026] (B) The enthalpy of fusion of polypropylene can be appropriately selected from the viewpoint of flexibility and heat resistance. (B) When heat resistance is important, the enthalpy of fusion of polypropylene may be 50-120 J / g, 60-115 J / g, 70-110 J / g, or 80-105 J / g. (B) When flexibility is important, the enthalpy of fusion of polypropylene may be 0-80 J / g, 1-50 J / g, 5-40 J / g, or 10-30 J / g.

[0027] In this specification, (B) the melting point and enthalpy of melting of polypropylene are calculated from the DSC second melting curve (the melting curve measured during the final heating process) measured using a differential scanning calorimetry (DSC) device in accordance with JIS K7121-1987, with a program that involves holding at 230°C for 5 minutes, cooling to -50°C at 10°C / min, holding at -50°C for 5 minutes, and heating to 230°C at 10°C / min. The melting point is the peak top temperature of the melting peak appearing in the second melting curve. If two or more melting peaks are observed, the peak top temperature of the melting peak with the largest peak top height is taken as the melting point. Furthermore, the following points should be noted when measuring and calculating: (1) The melting peak appearing in the DSC second melting curve of crystalline polypropylene usually has a long, gradual tail on the low-temperature side; (2) The tail on the high-temperature side often also has a long, gradual tail; (3) The baseline should be drawn so that the straight line extending the high-temperature baseline towards the low-temperature side and the straight line extending the low-temperature baseline towards the high-temperature side coincide, as shown in Figure 1 of JIS K7121-1987, 9. How to Read DTA or DSC Curves.

[0028] (B) According to JIS K7210-1:2014 for polypropylene, the melt mass flow rate measured under conditions of a temperature of 230°C and a load of 21.18N may be preferably 0.01 to 100 g / 10 min, more preferably 0.1 to 80 g / 10 min, even more preferably 0.5 to 60 g / 10 min, and even more preferably 1.0 to 40 g / 10 min, from the viewpoint of moldability.

[0029] (B) Examples of polypropylenes that can be used as polypropylene and have the above-mentioned properties include isotactic polypropylenes, syndiotactic polypropylenes, and atactic polypropylenes, such as propylene homopolymers and copolymers (including block copolymers and random copolymers) of propylene with one or more other α-olefins (e.g., ethylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene).

[0030] (B) One or more of these types of polypropylene may be used.

[0031] (B) The amount of polypropylene added is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, per 100 parts by mass of (A) isobutylene-isoprene copolymer elastomer, from the viewpoint of moldability. On the other hand, the amount of polypropylene added is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, even more preferably 60 parts by mass or less, and even more preferably 40 parts by mass or less, from the viewpoint of gas barrier properties and vibration damping characteristics.

[0032] (B) Polypropylene may, in one preferred embodiment, from the viewpoint of improving the moldability of the thermoplastic elastomer composition of the present invention, include (B1) polypropylene with a melt mass flow rate of 0.01 to 10 g / 10 min measured at a temperature of 230°C and a load of 21.18 N in accordance with JIS K7210-1:2014, and (B2) polypropylene with a melt mass flow rate of more than 10 g / 10 min and 100 g / 10 min or less measured at a temperature of 230°C and a load of 21.18 N in accordance with JIS K7210-1:2014. Hereinafter, an embodiment in which (B) polypropylene includes (B1) polypropylene and (B2) polypropylene may be referred to as "Embodiment A".

[0033] While there is no intention to be bound by theory, the following reasons are considered for the preference, from the viewpoint of improving the moldability of the thermoplastic elastomer composition of the present invention, for using (B) polypropylene containing (B1) polypropylene and (B2) polypropylene. When polypropylene with a large molecular weight (small melt mass flow rate) is used alone, the shear stress increases from the time it is extruded from the die or injected into the mold due to its large molecular weight, and molding defects caused by this (high shear stress) are likely to occur. On the other hand, when polypropylene with a small molecular weight (large melt mass flow rate) is used alone, because of its small molecular weight and high molecular mobility, phase separation from (A) isobutylene-isoprene copolymer elastomer and (C) hydrogenated block copolymer of aromatic vinyl compound and conjugated diene compound is likely to occur during the cooling and solidification process after it is extruded from the die or injected into the mold, and molding defects caused by this (phase separation) are likely to occur. Therefore, by using polypropylene with a high molecular weight and polypropylene with a low molecular weight in combination, both molding defects caused by high shear stress and molding defects caused by phase separation can be suppressed.

[0034] (B1) Polypropylene will be described below. (B1) Polypropylene is (B) Polypropylene, which is polypropylene with a melt mass flow rate of 0.01 to 10 g / 10 min measured at a temperature of 230°C and a load of 21.18 N in accordance with JIS K7210-1:2014. The melt mass flow rate of (B1) Polypropylene measured at 230°C and 21.18 N in accordance with JIS K7210-1:2014 may be preferably 0.1 to 10 g / 10 min, more preferably 0.5 to 10 g / 10 min, and even more preferably 1.0 to 10 g / 10 min, from the viewpoint of moldability.

[0035] (B1) The enthalpy of melt of polypropylene may be preferably 50 J / g or more, more preferably 60 J / g or more, even more preferably 70 J / g or more, and even more preferably 80 J / g or more, from the viewpoint of heat resistance. On the other hand, from the viewpoint of flexibility, the enthalpy of melt of polypropylene may be usually 120 J / g or less, preferably 115 J / g or less, and more preferably 110 J / g or less.

[0036] (B1) From the viewpoint of heat resistance, the melting point of polypropylene may be preferably 120°C or higher, more preferably 130°C or higher, even more preferably 140°C or higher, even more preferably 150°C or higher, and most preferably 160°C or higher. (B1) From the viewpoint of heat resistance, a higher melting point is preferable for polypropylene. However, since it is polypropylene, the melting point will probably be around 167°C at most.

[0037] (B1) Examples of polypropylenes that can be used as polypropylene and have the above-mentioned properties include propylene homopolymers and isotactic polypropylenes such as copolymers (including block copolymers and random copolymers) of propylene with one or more other α-olefins (e.g., ethylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene).

[0038] Furthermore, as one variation of Embodiment A, (B3) polypropylene, described later, may be used as (B1) polypropylene if its melt mass flow rate, measured under conditions of 230°C and 21.18N load in accordance with JIS K7210-1:2014, is 0.01 to 10 g / 10 min.

[0039] (B1) One or more of these types of polypropylene can be used.

[0040] (B2) Polypropylene will be described below. (B2) Polypropylene is (B) polypropylene, and according to JIS K7210-1:2014, the melt mass flow rate measured at a temperature of 230°C and a load of 21.18N is greater than 10 g / 10 min and 100 g / 10 min or less. According to JIS K7210-1:2014, the melt mass flow rate of (B2) polypropylene measured at a temperature of 230°C and a load of 21.18N may be preferably 15 to 80 g / 10 min, more preferably 20 to 60 g / 10 min, from the viewpoint of moldability.

[0041] (B2) The enthalpy of melt of polypropylene may be preferably 50 J / g or more, more preferably 60 J / g or more, even more preferably 70 J / g or more, and even more preferably 80 J / g or more, from the viewpoint of heat resistance. On the other hand, from the viewpoint of flexibility, the enthalpy of melt of polypropylene may be usually 120 J / g or less, preferably 115 J / g or less, and more preferably 110 J / g or less.

[0042] (B2) From the viewpoint of heat resistance, the melting point of polypropylene may be preferably 120°C or higher, more preferably 130°C or higher, even more preferably 140°C or higher, even more preferably 150°C or higher, and most preferably 160°C or higher. (B2) From the viewpoint of heat resistance, a higher melting point is preferable for polypropylene. However, since it is polypropylene, the melting point will probably be around 167°C at most.

[0043] (B2) Examples of polypropylenes that can be used as polypropylene and have the above-mentioned properties include propylene homopolymers and isotactic polypropylenes such as copolymers (including block copolymers and random copolymers) of propylene with one or more other α-olefins (e.g., ethylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene).

[0044] Another variation of Embodiment A may be used as (B2) polypropylene, which is (B3) polypropylene as described later, and which has a melt mass flow rate of more than 10 g / 10 min and 50 g / 10 min or less, measured under the conditions of a temperature of 230°C and a load of 21.18 N in accordance with JIS K7210-1:2014.

[0045] (B2) One or more of these types of polypropylene can be used.

[0046] The mass ratio of the amount of (B1) polypropylene to the amount of (B2) polypropylene (amount of (B1) / amount of (B2)) may be preferably 95 / 5 to 5 / 95, more preferably 80 / 20 to 10 / 90, and even more preferably 70 / 30 to 15 / 85, from the viewpoint of moldability.

[0047] The sum of the amounts of (B1) polypropylene and (B2) polypropylene is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, per 100 parts by mass of (A) isobutylene-isoprene copolymer elastomer, from the viewpoint of heat resistance and moldability. On the other hand, the sum of the amounts of (B1) polypropylene and (B2) polypropylene is usually 100 parts by mass or less, preferably 60 parts by mass or less, more preferably 50 parts by mass or less, even more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less, from the viewpoint of flexibility, gas barrier properties and vibration damping characteristics.

[0048] (B) Polypropylene may, in one of the other preferred embodiments, include (B3) polypropylene that satisfies the following properties (1) and (2) from the viewpoint of improving the balance between the flexibility and moldability of the thermoplastic elastomer composition of the present invention: (1) The enthalpy of melting is 50 J / g or less than 50 J / g. (2) The melt mass flow rate measured at a temperature of 230°C and a load of 21.18 N in accordance with JIS K7210-1:2014 is 0.01 to 50 g / 10 min. Hereinafter, embodiments in which (B) polypropylene includes (B3) polypropylene may be referred to as "Embodiment B".

[0049] (B3) Polypropylene will be described below. (B3) Polypropylene is (B) polypropylene that satisfies the above-described properties (1) and (2). (B3) Polypropylene may be amorphous or low-crystallinity. Here, "amorphous" means that no melting peak is observed in the DSC second melting curve. "Low-crystallinity" means that the enthalpy of melting calculated from the melting peak of the DSC second melting curve is greater than 0 J / g and less than 50 J / g.

[0050] (B3) From the viewpoint of heat resistance, polypropylene may preferably have a melting peak in the DSC second melting curve. From the viewpoint of heat resistance, the enthalpy of melting of (B3) polypropylene may preferably be 5 J / g or more, more preferably 10 J / g or more. On the other hand, from the viewpoint of flexibility, the enthalpy of melting of (B3) polypropylene may usually be less than 50 J / g, preferably 40 J / g or less, more preferably 30 J / g or less, even more preferably 25 J / g or less, and most preferably 20 J / g or less.

[0051] (B3) From the viewpoint of heat resistance, the melting point of polypropylene may be preferably 120°C or higher, more preferably 130°C or higher, even more preferably 140°C or higher, even more preferably 150°C or higher, and most preferably 155°C or higher. (B3) From the viewpoint of heat resistance, a higher melting point is preferable for polypropylene. However, since it is a propylene-based polyolefin, the melting point will probably be around 167°C at most.

[0052] (B3) The melt mass flow rate of polypropylene, measured in accordance with JIS K7210-1:2014 at a temperature of 230°C and a load of 21.18N, may, from the viewpoint of heat resistance, be normally 50 g / 10 min or less, preferably 40 g / 10 min or less, more preferably 30 g / 10 min or less, even more preferably 20 g / 10 min or less, and even more preferably 10 g / 10 min or less. On the other hand, the melt mass flow rate of (B3) polypropylene may, from the viewpoint of moldability, be preferably 0.01 g / 10 min or more, more preferably 0.1 g / 10 min or more, even more preferably 0.5 g / 10 min or more, and even more preferably 1.0 g / 10 min or more.

[0053] (B3) Examples of polypropylenes having the above-mentioned properties that can be used as polypropylene include atactic polypropylene, low stereoregularity polypropylene, and copolymers (including block copolymers and random copolymers) of propylene with one or more other α-olefins (e.g., ethylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene).

[0054] (B3) When polypropylene is a copolymer of the above-mentioned propylene and one or more other α-olefins, the content of constituent units derived from the α-olefin may be, depending on the stereoregularity and the amount of abnormal insertions, but from the viewpoint of imparting the above-mentioned amorphous or low crystallinity, it may be usually 5 to 50 mol% (content of constituent units derived from propylene 95 to 50 mol%), preferably 10 to 45 mol% (content of constituent units derived from propylene 90 to 55 mol%), and more preferably 15 to 40 mol% (content of constituent units derived from propylene 85 to 60 mol%).

[0055] Furthermore, as one variation of Embodiment B, a mixture of (B3) polypropylene with a melt mass flow rate of 0.01 to 10 g / 10 min measured under the conditions of a temperature of 230°C and a load of 21.18 N in accordance with JIS K7210-1:2014 and (B3) polypropylene with a melt mass flow rate of more than 10 g / 10 min and 50 g / 10 min or less measured under the conditions of a temperature of 230°C and a load of 21.18 N in accordance with JIS K7210-1:2014 may be used.

[0056] (B3) One or more of these types of polypropylene can be used.

[0057] (B3) The amount of polypropylene added is usually 5 parts by mass or more, preferably 10 parts by mass or more, and more preferably 15 parts by mass or more, per 100 parts by mass of (A) isobutylene-isoprene copolymer elastomer, from the viewpoint of flexibility and moldability. On the other hand, the amount of polypropylene added is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, even more preferably 60 parts by mass or less, and even more preferably 40 parts by mass or less, from the viewpoint of heat resistance, gas barrier properties and vibration damping characteristics.

[0058] (C) Hydrogenated block copolymers of aromatic vinyl compounds and conjugated diene compounds: The thermoplastic elastomer composition of the present invention comprises (C) a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound. The hydrogenated block copolymer of (C) an aromatic vinyl compound and a conjugated diene compound suppresses the bleeding of (D) a non-aromatic rubber softener and improves flexibility and moldability.

[0059] (C) A hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound is a substance obtained by adding hydrogen to a block polymer containing one or more aromatic vinyl compound polymer segments (c1) and one or more conjugated diene compound polymer segments (c2), thereby converting some or all of the carbon-carbon double bonds in the block polymer into carbon-carbon single bonds. (C) Examples of hydrogenated block copolymers of an aromatic vinyl compound and a conjugated diene compound include those having segment structures such as (c1)-(c2), (c1)-(c2)-(c1), (c2)-(c1)-(c2), (c1)-(c2)-(c1)-(c2), and (c1)-(c2)-(c1)-(c2)-(c1).

[0060] The above aromatic vinyl compounds are polymerizable monomers having polymerizable carbon-carbon double bonds and aromatic rings. Examples of the above aromatic vinyl compounds include styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N,N-diethyl-p-aminoethylstyrene, vinyltoluene, and p-tertiary butylstyrene. The above aromatic vinyl compounds may preferably contain styrene. (C) One or more of these aromatic vinyl compounds can be used in the production of hydrogenated block copolymers of aromatic vinyl compounds and conjugated diene compounds.

[0061] The above-mentioned conjugated diene compound is a polymerizable monomer having a structure in which two carbon-carbon double bonds are connected by one carbon-carbon single bond. Examples of the above-mentioned conjugated diene compounds include 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 1,3-octadiene, 1,3-cyclohexadiene, 2-methyl-1,3-octadiene, 1,3,7-octatriene, 7-methyl-3-methyleneocta-1,6-diene (β-myrcene), 3,7,11-trimethyl-1,3,6,10-dodecatetraene (α-farnesene), 7,11-dimethyl-3-methylene-1,6,10-dodecatriene (β-farnesene), and chloroprene (2-chloro-1,3-butadiene). The above-mentioned conjugated diene compound may preferably contain one or more selected from the group consisting of 1,3-butadiene, isoprene, β-myrcene, α-farnesene, and β-farnesene. (C) One or more of these conjugated diene compounds can be used as the above-mentioned conjugated diene compound used in the production of a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound.

[0062] (c1) The aromatic vinyl compound polymer segment is a polymer segment that mainly contains constituent units derived from the above aromatic vinyl compound. Here, "mainly contains" means that the content of constituent units derived from the above aromatic vinyl compound is more than 50% by mass and 100% by mass or less. From the viewpoint of heat resistance, the content of constituent units derived from the above aromatic vinyl compound may be preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and most preferably 99 to 100% by mass.

[0063] (c1) Examples of aromatic vinyl compound polymer segments include the homopolymer segment of the above aromatic vinyl compound and the copolymer segment of the above aromatic vinyl compound and the above conjugated diene compound. (c1) When there are two or more aromatic vinyl compound polymer segments, they may have the same structure or they may have different structures.

[0064] (c2) The conjugated diene compound polymer segment is a polymer segment that mainly contains structural units derived from the above conjugated diene compound. Here, "mainly contains" means that the content of structural units derived from the above conjugated diene compound is 50 to 100% by mass. From the viewpoint of flexibility, the content of structural units derived from the above conjugated diene compound may be preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and most preferably 99 to 100% by mass.

[0065] (c2) Examples of conjugated diene compound polymer segments include the homopolymer segment of the above conjugated diene compound and the copolymer segment of the above conjugated diene compound and the above aromatic vinyl compound. (c2) When there are two or more conjugated diene compound polymer segments, they may have the same structure or they may have different structures.

[0066] (C) The hydrogenation rate of the hydrogenated block copolymer of the aromatic vinyl compound and the conjugated diene compound (the ratio of the number of carbon-carbon single bonds obtained by hydrogenation to the number of carbon-carbon double bonds in the block copolymer of the aromatic vinyl compound and the conjugated diene compound before hydrogenation) is usually 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, and most preferably 90 to 100 mol% from the viewpoint of heat resistance.

[0067] (C) The content of the structural unit derived from the aromatic vinyl compound in the hydrogenated product of the block copolymer of an aromatic vinyl compound and a conjugated diene compound is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, and still more preferably 15 to 40% by mass from the viewpoints of flexibility and heat resistance.

[0068] (C) The polystyrene-reduced mass average molecular weight (Mw) determined from the differential molecular weight distribution curve (hereinafter sometimes abbreviated as "GPC curve") measured by gel permeation chromatography (hereinafter sometimes abbreviated as "GPC") of the hydrogenated product of the block copolymer of an aromatic vinyl compound and a conjugated diene compound is preferably 1.5×10 4 or more, more preferably 4.5×10 4 or more, and still more preferably 1.5×10 5 or more from the viewpoint of tensile properties. On the other hand, the mass average molecular weight (Mw) is preferably 1.5×10 6 or less, more preferably 1.2×10 6 or less from the viewpoint of molding processability.

[0069] (C) The polystyrene-reduced number average molecular weight (Mn) determined from the GPC curve of the hydrogenated product of the block copolymer of an aromatic vinyl compound and a conjugated diene compound is preferably 1.0×10 4 or more, more preferably 3.0×10 4 or more, and still more preferably 1.0×10 5 or more from the viewpoint of tensile properties. On the other hand, the number average molecular weight (Mn) is preferably 1.0×10 6 or less, more preferably 8.0×10 5 or less from the viewpoint of moldability.

[0070] (C) The GPC measurement of the hydrogenated product of the block copolymer of an aromatic vinyl compound and a conjugated diene compound can be carried out using a high-performance liquid chromatography system "HLC-8320 (trade name)" of Tosoh Corporation (a system including a degasser, a liquid delivery pump, an autosampler, a column oven, and a RI (differential refractive index) detector) as the system, and using two GPC columns "KF-806L (trade name)" of Shodex, one "KF-802 (trade name)", and one "KF-801 (trade name)", a total of four columns, connected in series in the order of KF-806L, KF-806L, KF-802, and KF-801 from the upstream side, using tetrahydrofuran (without stabilizer) as the mobile phase, and performing the measurement under the conditions of a column temperature of 40 °C, a flow rate of 1.0 mL / min, a sample concentration of 1 mg / mL, and a sample injection volume of 100 μL. The elution volume at each retention volume can be determined from the detection amount of the RI detector assuming that the molecular weight dependence of the refractive index of the measurement sample is absent. The calibration curve from each retention volume to the polystyrene-equivalent molecular weight can be created using standard polystyrene. At this time, it should be noted that the standard polystyrene to be used should be appropriately selected so that the retention volume of the measurement sample is interpolated into the plot of the calibration curve. For the theory and actual measurement of GPC, reference can be made to reference books such as "Size Exclusion Chromatography, High-Performance Liquid Chromatography of Polymers, Author: Sadao Mori, First Edition, First Printing, December 10, 1991" by Kyoritsu Shuppan Co., Ltd., and "Synthetic Polymer Chromatography, Editors: Hajime Ohtani, Tatsuya Takasaki (the upper part of '崎' is '立'), First Edition, First Printing, July 25, 2013" by Ohmsha, Ltd.

[0071] (C) Examples of hydrogenated block copolymers of aromatic vinyl compounds and conjugated diene compounds include styrene-ethylene-butene block copolymer (SEB), styrene-ethylene-propylene block copolymer (SEP), styrene-ethylene-butene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene copolymer block (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-butadiene-butylene-styrene copolymer (partially hydrogenated styrene-butadiene-styrene copolymer: SBBS), partially hydrogenated styrene-isoprene-styrene copolymer, partially hydrogenated styrene-isoprene-butadiene-styrene copolymer, and hydrogenated styrene-β-farnesene block copolymer.

[0072] (C) One or more of these can be used as hydrogenators for block copolymers of aromatic vinyl compounds and conjugated diene compounds.

[0073] (C) The amount of hydrogenated material added to the block copolymer of the aromatic vinyl compound and the conjugated diene compound is usually 1 part by mass or more, preferably 3 parts by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, per 100 parts by mass of (A) isobutylene-isoprene copolymer elastomer, from the viewpoint of suppressing the bleeding of (D) non-aromatic rubber softener and improving flexibility and moldability. On the other hand, from the viewpoint of heat resistance, the amount of hydrogenated material added to the block copolymer of the aromatic vinyl compound and the conjugated diene compound is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, even more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less.

[0074] (C) Hydrogenated block copolymers of aromatic vinyl compounds and conjugated diene compounds, in one preferred embodiment, have a polystyrene-equivalent molecular weight of 2.0 to 20 × 10 on the GPC curve. 4 The region, preferably 2.0 to 16 × 10 4The region, more preferably 2.0 to 12 × 10 4 It may have one or more elution peaks (L) with peak tops in the region. When the thermoplastic elastomer composition of the present invention is used in sealing members such as medical stoppers, it can suppress and prevent leakage when inserting or removing needles. Hereinafter, (C) as a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound, the polystyrene-equivalent molecular weight of the GPC curve is 2.0 to 20 × 10 4 Embodiments that use a molecule having one or more elution peaks (L) with peak tops in the region are sometimes referred to as "Embodiment C".

[0075] In Embodiment C, the ratio of the sum of peak top heights of the elution peaks (L) to the sum of peak top heights of the elution peaks (M) other than the elution peaks (L) that appear in the GPC curve (elution peak (L) / elution peak (M)) is usually 10 / 90 to 100 / 0, preferably 20 / 80 to 100 / 0, more preferably 30 / 70 to 98 / 2, even more preferably 50 / 50 to 95 / 5, and even more preferably 60 / 40 to 90 / 10.

[0076] While not intended to be bound by theory, the following considerations explain why, using the thermoplastic elastomer composition of Embodiment C, a sealing member is obtained that suppresses and prevents liquid leakage when inserting or removing a needle. A sealing member made of a thermoplastic elastomer composition has elastic properties, and when a needle is inserted into the sealing member / while the needle is inserted, stress acts to prevent a gap from forming between the sealing member and the needle / to seal the gap. On the other hand, a sealing member made of a thermoplastic elastomer composition also has viscous properties, and this stress gradually relaxes, so after the needle is removed from the sealing member, it takes a short amount of time for the hole / gap to be completely sealed. This time increases in proportion to the relaxation of the aforementioned stress, and therefore becomes longer when the needle is removed after being attached for a long time. Liquid leakage occurs when this time is long, and the thermoplastic elastomer composition of Embodiment C has relatively low molecular weight components (polystyrene equivalent molecular weight 2.0~20×10 on the GPC curve). 4 Because it contains components that exhibit a peak top in the region, in other words, components with a short relaxation time τ, or more precisely, components that readily undergo viscous flow, this time is sufficiently short, and no leakage occurs.

[0077] As one variation of Embodiment C, (C) a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound is (C1) the largest in the GPC curve and has a polystyrene-equivalent molecular weight of 2.0 to 20 × 10 4 The region, preferably 2.0 to 16 × 10 4 The region, more preferably 2.0 to 12 × 10 4 This may include a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound having an elution peak with its peak top in the region.

[0078] In this embodiment, with the total amount of hydrogenated blocks copolymers of all (C) aromatic vinyl compounds and conjugated diene compounds being 100% by mass, the amount of hydrogenated blocks copolymers of (C1) aromatic vinyl compounds and conjugated diene compounds may be typically 10 to 100% by mass, preferably 20 to 100% by mass, more preferably 30 to 98% by mass, even more preferably 50 to 95% by mass, and even more preferably 60 to 90% by mass, from the viewpoint of suppressing and preventing leakage and from the viewpoint of mechanical properties.

[0079] As another variation of Embodiment C, (C) a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound has a polystyrene-equivalent molecular weight of 2.0 to 20 × 10⁻¹⁶ on the GPC curve. 4 The region, preferably 2.0 to 16 × 10 4 The region, more preferably 2.0 to 12 × 10 4 The elution peak (L) has its peak top in the region, and the polystyrene-equivalent molecular weight is 20 × 10 4 A region exceeding 22-200 × 10 4 It may include at least one elution peak (H) with its peak top located in the specified region.

[0080] In this embodiment, the ratio of the sum of peak top heights of elution peaks (L) to the sum of peak top heights of elution peaks (H) (elution peaks (L) / elution peaks (H)) is usually 10 / 90 to 100 / 0, preferably 20 / 80 to 100 / 0, more preferably 30 / 70 to 98 / 2, even more preferably 50 / 50 to 95 / 5, and even more preferably 60 / 40 to 90 / 10.

[0081] As yet another variation of Embodiment C, (C) a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound is (C1) the hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound, and (C2) is the largest in the differential molecular weight distribution curve measured by gel permeation chromatography, and has a polystyrene-equivalent molecular weight of 20 × 10 4The region exceeding 22-200 × 10 4 The present invention includes a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound having an elution peak with a peak top in the region, preferably comprising (C1) a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound and (C2) a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound.

[0082] In this embodiment, the mass ratio (amount of (C1) / amount of (C2)) of the amount of hydrogenated block copolymer of (C1) an aromatic vinyl compound and a conjugated diene compound to the amount of hydrogenated block copolymer of (C2) an aromatic vinyl compound and a conjugated diene compound is usually 10 / 90 to 100 / 0, preferably 20 / 80 to 100 / 0, more preferably 30 / 70 to 98 / 2, even more preferably 50 / 50 to 95 / 5, and even more preferably 60 / 40 to 90 / 10.

[0083] (C) The hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound may, in one of the other preferred embodiments, include a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound having a constituent unit derived from (C3) β-farnesene, such as the hydrogenated styrene-β-farnesene block copolymer. Since β-farnesene is obtained by fermenting sugar from sugarcane, the environmental impact can be reduced. In addition, the presence of a constituent unit derived from β-farnesene can enhance flexibility.

[0084] As yet another variation of Embodiment C, a hydrogenated block copolymer of an aromatic vinyl compound having a structural unit derived from (C3)β-farnesene and a conjugated diene compound, having an elution peak (L), may be used as component (C1). A hydrogenated block copolymer of an aromatic vinyl compound having a structural unit derived from (C3)β-farnesene and a conjugated diene compound, having an elution peak (H), may be used as component (C2). Both may be used in combination.

[0085] (D) Non-aromatic rubber softeners: The thermoplastic elastomer composition of the present invention contains (D) a non-aromatic rubber softener. The non-aromatic rubber softener (D) enhances the flexibility of the thermoplastic elastomer composition of the present invention and suppresses molding defects caused by high shear stress.

[0086] (D) Non-aromatic rubber softeners are non-aromatic mineral oils (hydrocarbon compounds derived from petroleum, etc.) or synthetic oils (synthetic hydrocarbon compounds). Here, "non-aromatic" means that, in the case of mineral oils, they are not classified as aromatic in the following categories (the number of aromatic carbon atoms is less than 30%). In the case of synthetic oils, it means that aromatic monomers are not used.

[0087] Mineral oils used as rubber softeners are mixtures of one or more of the following: paraffin chains, naphthenic rings, and aromatic rings. Those with 30-45% of the naphthenic ring carbons are called naphthenic, those with 30% or more of the aromatic carbons are called aromatic, and those that do not belong to either naphthenic or aromatic, and where the number of carbons in the paraffin chains accounts for 50% or more of the total carbons, are called paraffinic.

[0088] (D) Examples of non-aromatic rubber softeners include paraffinic mineral oils such as linear saturated hydrocarbons, branched saturated hydrocarbons, and their derivatives; naphthenic mineral oils; and synthetic oils such as α-olefin oligomers such as ethylene-α-olefin copolymer oligomers, hydrogenated polyisobutylene, polyisobutylene, and polybutene. Here, α-olefin oligomers as (D) non-aromatic rubber softeners and (B) polypropylene are clearly distinguished in that the former is a liquid that flows at room temperature, while the latter is a solid (non-flowing) at room temperature.

[0089] (D) In ​​one preferred embodiment, the non-aromatic rubber softener may contain one or more selected from the group consisting of α-olefin oligomers and paraffinic mineral oils, from the viewpoint of suppressing bleed-out. In this case, the number of aromatic carbon atoms in the paraffinic mineral oil may be preferably 20% or less, more preferably 10% or less, and even more preferably 0 to 5%.

[0090] (D) The kinematic viscosity at 40°C of the non-aromatic rubber softener, as measured in accordance with JIS K2283:2000, is 80 mm in one embodiment, from the viewpoint of suppressing bleed-out and gas barrier properties. 2 / s or more, 300mm 2 / s or more, or 1000mm 2 It may be 10,000 mm² or more. On the other hand, the kinematic viscosity of (D) the non-aromatic rubber softener is preferably 10,000 mm² from the viewpoint of the effect of imparting flexibility and the ease of handling when manufacturing the thermoplastic elastomer composition of the present invention. 2 / s or less, more preferably 6000mm 2 / s or less, more preferably 3000mm 2 It can be less than or equal to / s.

[0091] (D) One or more of these can be used as non-aromatic rubber softeners.

[0092] (D) The amount of non-aromatic rubber softener added is usually 1 part by mass or more, preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, per 100 parts by mass of (A) isobutylene-isoprene copolymer elastomer, from the viewpoint of moldability. (D) The amount of non-aromatic rubber softener added is 20 parts by mass or more, 30 parts by mass or more, 40 parts by mass or more, 50 parts by mass or more, or 60 parts by mass or more in one embodiment, from the viewpoint of obtaining a desired level of flexibility. On the other hand, (D) the amount of non-aromatic rubber softener added is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, even more preferably 100 parts by mass or less, and even more preferably 80 parts by mass or less, from the viewpoint of suppressing bleed-out. (D) The amount of non-aromatic rubber softener added may be 60 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, or 20 parts by mass or less in one embodiment, from the viewpoint of obtaining the desired gas barrier properties.

[0093] (E) Phenolic resin crosslinking agent: The thermoplastic elastomer composition of the present invention contains (E) a phenolic resin crosslinking agent. The (E) phenolic resin crosslinking agent crosslinks (A) an isobutylene-isoprene copolymer elastomer, thereby improving the heat resistance and mechanical properties of the thermoplastic elastomer composition of the present invention.

[0094] (E) Phenolic resin crosslinking agents can be obtained by condensing a bifunctional phenol dialcohol compound, or by condensing a phenol or alkyl-substituted phenol with an aldehyde compound, preferably formaldehyde, in an alkaline medium.

[0095] (E) Examples of phenolic resin crosslinking agents include condensates of bifunctional phenol dialcohol compounds such as dimethylolalkylphenol resin, condensates of halogenated bifunctional phenol dialcohol compounds such as halogenated dimethylolalkylphenol resin, condensates of phenol and aldehyde compounds such as phenol formaldehyde resin, halogenated products of said condensates, condensates of alkyl-substituted phenol and aldehyde compounds such as alkylphenol formaldehyde resin, and halogenated alkylphenol formaldehyde resin.

[0096] The above-mentioned dimethylolalkylphenol resin is a condensate of a dimethylolphenol compound having a hydrocarbon group at the p position, preferably a hydrocarbon group having 1 to 15 carbon atoms, more preferably a saturated hydrocarbon group having 1 to 15 carbon atoms, and even more preferably a saturated hydrocarbon group having 1 to 10 carbon atoms.

[0097] The above-mentioned halogenated dimethylolalkylphenol resin is a resin having a structure in which at least one of the terminal alcoholic hydroxyl groups of the above-mentioned dimethylolalkylphenol resin is halogenated with a halogen element such as bromine.

[0098] The alkylphenol formaldehyde resin described above is a condensate of formaldehyde and an alkyl-substituted phenol having a hydrocarbon group at the o, m, or p position, preferably at the p position, preferably a hydrocarbon group having 1 to 15 carbon atoms, more preferably a saturated hydrocarbon group having 1 to 15 carbon atoms, and even more preferably a saturated hydrocarbon group having 1 to 10 carbon atoms.

[0099] The above-mentioned halogenated alkylphenol formaldehyde resin is a resin having a structure in which at least one of the terminal alcoholic hydroxyl groups of the alkylphenol formaldehyde resin is halogenated with a halogen element such as bromine.

[0100] (E) One or more of these can be used as the phenolic resin crosslinking agent.

[0101] (E) The amount of phenolic resin crosslinking agent blended is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, even more preferably 2.0 parts by mass or more, and even more preferably 3.0 parts by mass or more, per 100 parts by mass of (A) isobutylene-isoprene copolymer elastomer, from the viewpoint of heat resistance and mechanical properties. On the other hand, the amount of (E) phenolic resin crosslinking agent blended is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, even more preferably 15 parts by mass or less, even more preferably 12 parts by mass or less, and most preferably 9 parts by mass or less, from the viewpoint of moldability.

[0102] (F) Crosslinking accelerator: In one preferred embodiment, the thermoplastic elastomer composition of the present invention may further contain (F) at least one or more crosslinking promoters selected from the group consisting of zinc oxide, magnesium oxide, and stannous chloride. (E) The crosslinking function of the phenolic resin crosslinking agent can be expressed more effectively.

[0103] (F) The amount of the crosslinking accelerator is an optional component and is not particularly limited as long as it does not contradict the purpose of the present invention. (F) The amount of the crosslinking accelerator is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass or more, per 100 parts by mass of (A) isobutylene-isoprene copolymer elastomer, from the viewpoint of reliably obtaining its effect. On the other hand, (F) the amount of the crosslinking accelerator is preferably 6 parts by mass or less, more preferably 4 parts by mass or less, and even more preferably 2 parts by mass or less, from the viewpoint of moldability.

[0104] (G) Petroleum resin, etc.: In one preferred embodiment, the thermoplastic elastomer composition of the present invention may further contain one or more selected from the group consisting of (G) petroleum resins, terpene resins, and rosins (hereinafter sometimes abbreviated as "(G) petroleum resin, etc."). By including (G) petroleum resin, etc., the vibration damping characteristics of the thermoplastic elastomer composition of the present invention can be improved.

[0105] The above-mentioned petroleum resin is an unsaturated hydrocarbon compound produced by the decomposition of naphtha, etc., and is a polymer of an unsaturated hydrocarbon compound with a large number of carbon atoms (usually around 4 to 20 carbon atoms) (including derivatives such as hydrogenated polymers of the polymer). The above-mentioned unsaturated hydrocarbon compound used as a monomer for the above-mentioned petroleum resin is typically an aliphatic unsaturated hydrocarbon compound, and / or an aromatic unsaturated hydrocarbon compound.

[0106] Examples of the above-mentioned aliphatic unsaturated hydrocarbon compounds include 1-butene, 2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, 3-hexene, 1-heptene, 2-heptene, 3-heptene, 1,3-pentadiene, cyclopentadiene (cyclopenta-1,3-diene), methylcyclopentadiene, ethylcyclopentadiene, 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), and dicyclopentadiene (tricyclo[5.2.1.02,6]deca-3,8-diene).

[0107] Examples of the above-mentioned aromatic unsaturated hydrocarbon compounds include styrene, α-methylstyrene, β-methylstyrene, 4-methylstyrene, vinylxylene, indene, methylindene, and ethylindene.

[0108] One or more of the above unsaturated hydrocarbon compounds can be used as monomers for the above petroleum resin.

[0109] Examples of the terpene resins mentioned above include polymers of terpenes (hydrocarbons with isoprene as a constituent unit), copolymers of terpenes and phenols, and copolymers of terpenes and monomers copolymerizable with terpenes, such as copolymers of terpenes and styrenes.

[0110] Examples of the above-mentioned rosins include gum rosin, wood rosin, and tall oil rosin, as well as hydrogenated rosin and rosin derivatives such as rosin esters (esters of rosin and polyhydric alcohols).

[0111] (G) Petroleum resins, etc. are preferably hydrogenated from the viewpoint of miscibility with (A) isobutylene-isoprene copolymer elastomers, (B) polypropylene, (C) propylene-based flexible polyolefins, and (D) non-aromatic rubber softeners. The hydrogenation rate of (G) petroleum resins, etc. (the ratio of the number of carbon-carbon single bonds that become carbon-carbon bonds due to hydrogenation to the number of carbon-carbon double bonds in (D) petroleum resins, etc. before hydrogenation) is preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 95 to 100 mol%. The above hydrogenation can be carried out by known methods, for example, by treatment with a hydrogenation catalyst in an inert solvent.

[0112] (G) The softening point of petroleum resin, etc., is preferably 90°C or higher, more preferably 100°C or higher, even more preferably 110°C or higher, even more preferably 120°C or higher, and most preferably 130°C or higher, from the viewpoint of heat resistance. On the other hand, (G) the softening point of petroleum resin, etc., is preferably 200°C or lower, more preferably 180°C or lower, and even more preferably 160°C or lower, from the viewpoint of moldability. Here, the softening point is measured according to JIS K2207-1996 6.4 Softening point test method (ring and ball method).

[0113] (G) One or more of these types of petroleum resins may be used.

[0114] (G) The amount of petroleum resin etc. is not particularly limited as it is an optional component. If vibration damping characteristics are particularly important, a large amount of (G) petroleum resin etc. may be added. The amount of (G) petroleum resin etc. is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, per 100 parts by mass of (A) isobutylene-isoprene copolymer elastomer. On the other hand, the amount of (G) petroleum resin etc. is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, even more preferably 60 parts by mass or less, and even more preferably 40 parts by mass or less, from the viewpoint of gas barrier properties, heat resistance and flexibility.

[0115] The thermoplastic elastomer composition of the present invention may optionally further contain components other than those listed above (A) to (G), to the extent that it does not contradict the purpose of the present invention.

[0116] Examples of the above optional components include (A) isobutylene-isoprene copolymer elastomers, (B) polypropylene, (C) hydrogenated block copolymers of aromatic vinyl compounds and conjugated diene compounds, and (G) other thermoplastic resins or thermoplastic elastomers other than petroleum resins, (D) other softeners or plasticizers other than non-aromatic rubber softeners, (E) phenolic resin crosslinking agents, and (F) other crosslinking agents or crosslinking accelerators other than crosslinking accelerators, as well as fillers, additives, colorants, and flame retardants.

[0117] Examples of the above-mentioned other thermoplastic resins or thermoplastic elastomers include ethylene-α-olefin-non-conjugated polyene copolymer elastomers, ethylene-α-olefin copolymer elastomers, polyethylene, and block copolymers (unhydrogenated) of aromatic vinyl compounds and conjugated diene compounds.

[0118] Examples of the above-mentioned other crosslinking agents or crosslinking accelerators include silicone resin crosslinking agents such as methylhydrogen polysiloxane and alkylmethylpolysiloxane; sulfur compounds, maleimide resin crosslinking agents, and organic peroxides such as 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

[0119] Examples of the above-mentioned fillers include inorganic fillers such as talc, calcium carbonate, silica (silicon dioxide), mica, clay, hydrotalcite, and zeolite; and organic fillers such as cross-linked acrylic resin particles.

[0120] Examples of the above additives include weathering agents such as anti-aging agents, light stabilizers, and ultraviolet absorbers; antioxidants such as hindered phenol antioxidants, phosphite antioxidants, thioether antioxidants, and amine antioxidants; lubricants such as acid amides, fatty acids, fatty acid esters, fatty acid metal salts, waxes such as polyethylene wax, modified waxes such as modified polyethylene wax, silicone oil, and modified silicone oil; nucleating agents such as aromatic metal phosphate salts and gelols; antistatic agents such as glycerin fatty acid esters; and hydrolysis inhibitors, mold release agents, processing aids, and anti-contamination agents.

[0121] Examples of the above-mentioned colorants include inorganic colorants such as titanium dioxide (titania), red iron oxide (ferric oxide), ultramarine (ultramarine blue), and carbon black; and organic colorants such as aniline black, quinacridone red, isoindolinone yellow, and phthalocyanine blue.

[0122] Examples of the above-mentioned flame retardants include antimony-based flame retardants, halogen-based flame retardants, metal hydroxides, zinc-based flame retardants, organophosphate ester-based flame retardants, and nitrogen-containing compound-based flame retardants.

[0123] As the optional components mentioned above, one or more of these may be used.

[0124] When using the above optional components, the amount of such components is not particularly limited, as they are optional components, as long as it does not contradict the purpose of the present invention. When using the above optional components, the amount of such components may be 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, 20 parts by mass or less, 10 parts by mass or less, 5 parts by mass or less, 3 parts by mass or less, 1 part by mass or less, 0 to 0.5 parts by mass, or approximately 0.01 to 50 parts by mass, per 100 parts by mass of (A) isobutylene-isoprene copolymer elastomer, in one embodiment.

[0125] In one embodiment, the thermoplastic elastomer composition of the present invention may not contain any one or more of the above-mentioned optional components.

[0126] In this specification, "not containing any of the above optional components" means that the component is not intentionally included. In the art of thermoplastic elastomer compositions, when an optional component is intentionally included, it is usually added in an amount of 0.01 parts by mass or more per 100 parts by mass of elastomer. Therefore, "not containing any of the above optional components" can also be rephrased as the content of the component being less than 0.01 parts by mass, preferably 0.001 parts by mass or less, and more preferably 0 to 0.0001 parts by mass, per 100 parts by mass of (A) isobutylene-isoprene copolymer elastomer.

[0127] 2. Manufacturing method: The thermoplastic elastomer composition of the present invention can be obtained by using any melt kneader to simultaneously or in any order introduce components (A) to (E) and any optional components to be used, and melt kneading, preferably at a resin temperature of 180 to 240°C. The kneading time is preferably 1 minute or more, more preferably 3 to 20 minutes, and even more preferably 5 to 10 minutes.

[0128] Examples of the above-mentioned melting and mixing machines include batch mixers such as pressure kneaders and mixers; extrusion mixers such as single-screw extruders, co-rotating twin-screw extruders, and opposite-rotating twin-screw extruders; and calender roll mixers. These may be used in any combination.

[0129] The resulting thermoplastic elastomer composition can be pelletized by any method and then molded into any article by any molding method. Pelletization can be carried out by methods such as hot cutting, strand cutting, and underwater cutting.

[0130] Alternatively, the obtained thermoplastic elastomer composition may be used directly for molding (without going through the pelletizing process).

[0131] 3. Goods: The articles of the present invention include the thermoplastic elastomer composition of the present invention. The articles of the present invention can be obtained by using the thermoplastic elastomer composition of the present invention and molding it into a desired shape by any molding method. Examples of such molding methods include injection molding, extrusion molding, blow molding, press molding, compression molding, and methods combining two or more of these.

[0132] Examples of articles of the present invention include medical articles such as syringes and medical containers, food packaging articles such as beverage containers, printer articles such as ink cartridges and toner cartridges, sealing members such as stoppers, gaskets and packings used in these articles, vibration damping members and soundproofing members for automobiles, and vibration damping members and soundproofing members for home appliances such as audio equipment, refrigerators, vacuum cleaners and air conditioners. [Examples]

[0133] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0134] Measurement method The tests (b) to (e) below were performed after conditioning the test specimens for 16 hours or more in an environment of 23±2℃ and 50±10% relative humidity, and then under the same temperature and humidity conditions unless otherwise specified.

[0135] (i) Extrusion moldability: Using a thermoplastic elastomer composition, a sheet with a width of 50 mm and a thickness of 0.5 mm was extruded using a 40 mm extruder at a die outlet resin temperature of 200 °C. The obtained sheets were evaluated based on visual inspection and tactile feel according to the following criteria. A (Excellent): The sheet's shape was very stable, the edges were very clean, the surface of the sheet was very smooth, and it had a very smooth feel. B (Good): The sheet had a stable shape, clean edges, a smooth surface, and a pleasant feel. C (Pass): The sheet had a stable shape, clean edges, and a smooth surface, but it had a slightly powdery texture. D (Fail): The sheet's shape was unstable, and the edges were not clean. In addition, the sheet's surface had powdery bumps and flow marks.

[0136] (b) Durometer hardness (Type A): In accordance with JIS K6253-2012, a 6.3 mm thick press sheet made using a thermoplastic elastomer composition was used as a test specimen, and the 15-second value of the durometer hardness (Type A) was measured. In the table, durometer hardness (Type A) is indicated as "Hardness A".

[0137] (h) Tensile properties: In accordance with JIS K6251:2017, a thermoplastic elastomer composition was used, and an injection molding machine with a clamping pressure of 120 tons was used. Under the conditions of a molding temperature of 220°C, mold temperature of 30°C, injection speed of 55 mm / sec, injection pressure of 140 MPa, holding pressure of 40 MPa, injection time of 5 seconds, and cooling time of 20 seconds, a dumbbell-shaped No. 3 test specimen was punched out from a sheet measuring 130 mm in length, 130 mm in width, and 2 mm in thickness. A tensile test was performed at a test speed of 500 mm / min, and the tensile fracture stress (unit: MPa), 100% strain tensile stress (unit: MPa), and tensile fracture strain (unit: %) were calculated from the obtained stress-strain curve.

[0138] (ii) Compression set: In accordance with JIS K6262-2003, test specimens were punched out from a 6.3 mm thick press sheet made using a thermoplastic elastomer composition, and the compression set (in %) was measured under the conditions of 25% compression deformation, a temperature of 120°C, and 22 hours.

[0139] (e) Gas barrier properties: Using the GTR-20XART differential pressure type transmittance measuring device (product name) from GTR Tech Co., Ltd., and following the device's instruction manual and JIS K7126-1:2006 Plastics - Films and Sheets - Gas Permeability Test Method Part 1: Differential Pressure Method, samples were punched out from a 0.3 mm thick press sheet made from a thermoplastic elastomer composition, and the oxygen permeability (unit: cm) was measured under test conditions of 40°C and 90% relative humidity. 3 / (m 2 (day / atm), and moisture permeability (unit: cm) 3 / (m 2 The following measurements were taken: The amount of oxygen permeating was measured according to Annex 2 (gas chromatography method) of the above JIS standard. The oxygen partial pressure on the high-pressure side (supply side) was set to 71.02 cmHg (94.69 kPa).

[0140] Raw materials used (A) Isobutylene / isoprene copolymer elastomer (A-1) Butyl rubber "Butyl 268 (product name)" from Nippon Butyl Co., Ltd.

[0141] (B) Polypropylene: (B1-1) BC3HF (trade name), a block copolymer of propylene and ethylene from Nippon Polypropylene Co., Ltd., melt mass flow rate (temperature 230°C, load 21.18N) 8.5g / 10min, melting point 164°C, enthalpy of fusion 88J / g. (B1-2) Propylene homopolymer "PX201N (product name)" from Sun Allomer Co., Ltd., melt mass flow rate (temperature 230℃, load 21.18N) 0.8g / 10min, melting point 163℃, enthalpy of fusion 87J / g.

[0142] (B2-1) Propylene homopolymer "PM900A (product name)" manufactured by Sun Allomer Co., Ltd., melt mass flow rate (temperature 230℃, load 21.18N) 30g / 10min, melting point 163℃, enthalpy of fusion 106J / g.

[0143] (B3-1) Mitsui Chemicals, Inc.'s flexible polypropylene "Toughmer PN3560 (product name)" has a melt mass flow rate (temperature 230℃, load 21.18N) of 6.0g / 10min, a melting point of 162℃, and an enthalpy of fusion of 16J / g. According to Japanese Patent Publication No. 2020-111709, it is a propylene-ethylene-1-butene copolymer with a content of 15 mol% (10 mass%) of constituent units derived from ethylene, 15 mol% (20 mass%) of constituent units derived from 1-butene, and 70 mol% (70 mass%) of constituent units derived from propylene.

[0144] (C) Hydrogenated block copolymers of aromatic vinyl compounds and conjugated diene compounds: (C1-1) Kuraray Co., Ltd.'s hydrogenated block copolymer of styrene and isoprene (styrene-ethylene-propylene-styrene copolymer) "Septon 2002 (product name)", styrene-derived constituent unit content 30% by mass, mass-average molecular weight (Mw) in polystyrene equivalent determined from GPC curve 4.3 × 10 4 , number average molecular weight (Mn) 4.0×10 4The peak top is molecular weight 4.9 × 10 4 It has the maximum elution peak at this position.

[0145] (C2-1) Kuraray Co., Ltd.'s hydrogenated block copolymer of styrene and isoprene (styrene-ethylene-ethylene-propylene-styrene copolymer) "Septon 4077 (product name)", styrene-derived constituent unit content 30% by mass, mass-average molecular weight (Mw) in polystyrene equivalent calculated from GPC curve 38 × 10 4 , number average molecular weight (Mn) 26×10 4 The peak top is molecular weight 47 × 10 4 It has the maximum elution peak at this position. (C2-2) Hydrogenated block copolymer of styrene and 1,3-butadiene (styrene-ethylene-butene-styrene copolymer) "Taipol 6159 (trade name)" from Taiwan Synthetic Rubber Co., Ltd. (TSRC), styrene-derived constituent unit content 30% by mass, mass-average molecular weight (Mw) of polystyrene equivalent determined from GPC curve 41 × 10⁻⁶ 4 , number average molecular weight (Mn) 27×10 4 The peak top is molecular weight 51 × 10 4 It has the maximum elution peak at this position.

[0146] (C3-1) Kuraray Co., Ltd.'s hydrogenated styrene-β-farnesene block copolymer "Septon BIO SF904 (product name)", styrene-derived constituent unit content 21% by mass, mass-average molecular weight (Mw) in polystyrene equivalent calculated from GPC curve 8.6 × 10 4 , number average molecular weight (Mn) 7.8×10 4 The peak top is molecular weight 9.7 × 10 4 It has the maximum elution peak at this position.

[0147] (D) Non-aromatic rubber softeners: (D-1) Paraffin oil "Diana Process Oil PW-90 (product name)" from Idemitsu Kosan Co., Ltd. Kinematic viscosity at 40°C measured according to JIS K2283:2000: 90 mmHg 2 / s. (D-2) Synthetic oil "Lucant LX010 (product name)" manufactured by Mitsui Chemicals, Inc. Kinematic viscosity at 40°C was 1300 mmHg, measured according to JIS K2283:2000. 2 / s.

[0148] (E) Phenolic resin crosslinking agent: (E-1) Taoka Chemical Industry Co., Ltd.'s alkylphenol formaldehyde resin (CAS number 26678-93-3) is the active ingredient in the phenol resin crosslinking agent "Tackirol 202 (product name)," with an active ingredient content of over 90% by mass. The table shows the amount used for "Tackirol 202 (product name)."

[0149] (F) Crosslinking accelerator: (F-1) Anhydrous stannous chloride. CAS number 7772-99-8. (F-2) Two types of zinc oxide as specified in JIS K1410-1995.

[0150] (G) Petroleum resin, etc.: (G-1) Idemitsu Kosan Co., Ltd.'s petroleum resin "iMarb P-140 (product name)," a hydrogenated copolymer of dicyclopentadiene and aromatic unsaturated hydrocarbon compounds. Softening point: 140°C. (G-2) YS Polystar T145 (product name), a terpene phenol resin from Yasuhara Chemical Co., Ltd. Softening point: 145°C.

[0151] Example 1 A mixture consisting of 100 parts by mass of component (A-1), 6 parts by mass of component (B1-1), 15 parts by mass of component (B2-1), 15 parts by mass of component (C1-1), 3 parts by mass of component (C2-1), 40 parts by mass of component (D-1), 6 parts by mass of component (E-1), 0.36 parts by mass of component (F-1), and 0.54 parts by mass of component (F-2) was melt-kneaded using a 20L capacity pressurized kneader under the conditions of a resin temperature of 200°C at discharge and a kneading time of 5 to 10 minutes to obtain a thermoplastic elastomer composition. Tests (a) to (e) above were performed. The results are shown in Table 1.

[0152] Examples 2-19 A thermoplastic elastomer composition was obtained in the same manner as in Example 1, except that the formulation was changed as shown in one of Tables 1 to 3. Tests (a) to (e) above were performed. The results are shown in one of Tables 1 to 3. Note that significant bleed-out of the rubber softener was observed in the extruded sheet obtained in test (a) above, the press sheets prepared for tests (b), (d), and (e) above, and the injection-molded sheet molded for test (c) above, using the thermoplastic elastomer composition of Example 19.

[0153] [Table 1]

[0154] [Table 2]

[0155] [Table 3]

[0156] The thermoplastic elastomer composition of the present invention was found to have an excellent balance of moldability, flexibility, and heat resistance. Furthermore, since no bleed-out of the rubber softener was observed in the injection-molded sheet for the tensile properties in the above test (c), it was concluded that bleed-out of the rubber softener was also suppressed. The preferred thermoplastic elastomer composition of the present invention was also found to have good mechanical properties and gas barrier properties. Therefore, it was concluded that the thermoplastic elastomer composition of the present invention can be suitably used as a material for sealing members such as plugs, gaskets, and packings used in various articles, such as medical plugs.

[0157] (H) Loss tangent tanδ (an index of vibration damping characteristics) For Examples 1 and 2, (e) the loss tangent tanδ was also measured. Using a dynamic viscoelasticity analyzer, a sample measuring 25 mm in length and 10 mm in width, taken from a 1 mm thick press sheet made of a thermoplastic elastomer composition, was set with a chuck distance of 5 mm. The temperature-loss tangent curve was obtained under the following conditions: tension mode, frequency of 1 Hz, and temperature -80°C for 1 minute, followed by heating to 80°C at a heating rate of 4°C / min. The same measurement was taken for a frequency of 10 Hz.

[0158] Figure 1 shows the temperature-loss tangent curve of a press sheet prepared using the thermoplastic elastomer composition of Example 1, and Figure 2 shows the temperature-loss tangent curve of a press sheet prepared using the thermoplastic elastomer composition of Example 2. These results show that the thermoplastic elastomer composition of the present invention also has good vibration damping characteristics. Furthermore, it was found that the vibration damping characteristics can be improved by using (G) petroleum resin, etc. Therefore, it was concluded that the thermoplastic elastomer composition of the present invention can be suitably used as vibration damping members and soundproofing members for automobiles, as well as vibration damping members and soundproofing members for home appliances such as audio equipment, refrigerators, vacuum cleaners, and air conditioners.

[0159] (T) Leakage resistance For Examples 1, 4, and 5, a further (t) leakage resistance test was also performed. Using a thermoplastic elastomer composition, a cylindrical test specimen with a diameter of 22 mm and a height of 5.6 mm was prepared by injection molding at a temperature of 220°C and an injection pressure of 150 MPa. Next, 500 ml of distilled water was placed inside a polypropylene fitting unit with a volume of 1000 ml, an inner diameter of 18 mm at the mouth, and a neck length of 8 mm, where the inner diameter of the neck portion was constant. The test specimen and the fitting unit were then sealed together using tape to prevent water leakage (see Figure 3). Subsequently, a 3.6 mm diameter plastic needle (JY-ND323L (product name) from JMS Co., Ltd.) was inserted into the test specimen, and the fitting unit with the test specimen attached was inverted. It was then left in this state at a temperature of 23°C and a relative humidity of 50% for 24 hours. After that, the plastic needle was removed, and a visual inspection was performed for 1 minute to determine whether or not water leakage occurred from the test specimen. The same test was repeated five times, and the number of times there were no leaks was recorded.

[0160] The results were as follows: Example 1 had 5 leaks (0 leaks), Example 4 had 3 leaks (2 leaks), and Example 5 had 5 leaks (0 leaks). From these results, it was found that the preferred thermoplastic elastomer composition of the present invention also has good resistance to liquid leakage. Furthermore, (C) as a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound, the polystyrene-equivalent molecular weight of the GPC curve was 2.0 to 20 × 10 4 It was found that by using a material that includes an elution peak with its peak top in the specified region, the resistance to liquid leakage can be improved. Therefore, it was considered that the preferred thermoplastic elastomer composition of the present invention can be suitably used as a sealing member such as a medical stopper, and in particular as a material for a medical injection stopper. [Brief explanation of the drawing]

[0161] [Figure 1] This is the temperature-loss tangent curve of a press sheet prepared using the thermoplastic elastomer composition of Example 1. [Figure 2] This is the temperature-loss tangent curve of a press sheet prepared using the thermoplastic elastomer composition of Example 2. [Figure 3] This is a conceptual diagram explaining the liquid leakage resistance test. [Explanation of symbols]

[0162] 1: Inner diameter of the opening 2: Length of the mouth and neck 3: Test piece fitted into the opening of the mating unit 4: Water placed inside the mating unit

Claims

1. (A) Isobutylene / isoprene copolymer elastomer 100 parts by mass, (B) Polypropylene 5 to 100 parts by mass, (C) Hydrogenated block copolymer of aromatic vinyl compound and conjugated diene compound: 1 to 100 parts by mass, (D) 1 to 200 parts by mass of non-aromatic rubber softener, and (E) Phenolic resin crosslinking agent: 0.5 to 25 parts by mass, A thermoplastic elastomer composition containing the following:

2. The hydrogenated block copolymer of component (C) of an aromatic vinyl compound and a conjugated diene compound, as measured by gel permeation chromatography, shows a polystyrene-equivalent molecular weight of 2.0 to 20 × 10⁻⁶ in the differential molecular weight distribution curve. ４ The thermoplastic elastomer composition according to claim 1, having one or more elution peaks with peak tops in the region.

3. The above component (C) is a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound, (C1) The differential molecular weight distribution curve measured by gel permeation chromatography is the maximum, and the polystyrene-equivalent molecular weight is 2.0 to 20 × 10 ４ The hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound has an elution peak with a peak top in the region, The thermoplastic elastomer composition according to claim 1.

4. The above component (C) is a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound, The above-mentioned component (C1) is a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound, and (C2) The differential molecular weight distribution curve measured by gel permeation chromatography is the largest, and the polystyrene-equivalent molecular weight is 20 × 10 ４ This includes a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound having an elution peak with a peak top in the region exceeding the limit. The thermoplastic elastomer composition according to claim 3.

5. The thermoplastic elastomer composition according to claim 4, wherein the mass ratio (amount of component (C1) / amount of component (C2)) of the amount of hydrogenated block copolymer of component (C1) and a conjugated diene compound to the amount of hydrogenated block copolymer of component (C2) is 20 / 80 to 98 / 2.

6. The thermoplastic elastomer composition according to claim 1, wherein the above component (C) hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound comprises (C3) a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound having a structural unit derived from β-farnesene.

7. The above component (B) polypropylene (B1) According to JIS K7210-1:2014, the melt mass flow rate measured under conditions of a temperature of 230°C and a load of 21.18 N is 0.01 to 10 g / 10 min for polypropylene. (B2) Polypropylene containing a melt mass flow rate greater than 10 g / 10 min and less than or equal to 100 g / 10 min, measured at a temperature of 230°C and a load of 21.18 N in accordance with JIS K7210-1:2014. The thermoplastic elastomer composition according to claim 1.

8. The thermoplastic elastomer composition according to claim 7, wherein the mass ratio of the amount of component (B1) polypropylene to the amount of component (B2) polypropylene (amount of component (B1) / amount of component (B2)) is 95 / 5 to 5 / 95.

9. The thermoplastic elastomer composition according to claim 1, wherein the above component (B) polypropylene comprises (B3) polypropylene that satisfies the following properties (1) and (2): (1) The enthalpy of melting is less than 50 J / g. (2) The melt mass flow rate measured under conditions of a temperature of 230°C and a load of 21.18 N, in accordance with JIS K7210-1:2014, is 0.01 to 50 g / 10 min.

10. The thermoplastic elastomer composition according to claim 9, wherein the melting point of the above component (C) propylene-based flexible polyolefin is 130°C or higher.

11. The thermoplastic elastomer composition according to claim 9, wherein the melting enthalpy of the above component (C) propylene-based flexible polyolefin is 5 to 30 J / g.

12. The kinematic viscosity at 40°C of the above component (D), a non-aromatic rubber softener, as measured according to JIS K2283:2000, is between 1,000 and 10,000 mm². ２ A thermoplastic elastomer composition according to any one of claims 1 to 11, wherein the value is 1 / s or more.

13. Furthermore, the thermoplastic elastomer composition according to any one of claims 1 to 11, comprising (G) one or more selected from the group consisting of petroleum resins, terpene resins, and rosins, in an amount of 1 to 100 parts by mass per 100 parts by mass of the above component (A) isobutylene / isoprene copolymer elastomer.

14. An article comprising the thermoplastic elastomer composition according to any one of claims 1 to 11.

15. An article comprising the thermoplastic elastomer composition according to claim 12.

16. An article comprising the thermoplastic elastomer composition described in claim 13.

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