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JP-7855076-B2 - Thermoplastic elastomer composition and molded article thereof

JP7855076B2JP 7855076 B2JP7855076 B2JP 7855076B2JP-7855076-B2

Inventors

  • 柴田 泰裕
  • 千蒲 翔
  • 山本 昭広

Assignees

  • 三井化学株式会社

Dates

Publication Date
20260507
Application Date
20230912
Priority Date
20220913

Claims (12)

  1. The material comprises a crosslinked product of an ethylene-α-olefin-non-conjugated polyene copolymer (A) that satisfies the following requirements (a1) to (a4) (wherein the α-olefin has 3 or more carbon atoms) and a phenol resin-based crosslinking agent (E), and per 100 parts by mass of the copolymer (A), 360 to 460 parts by mass of crystalline polyolefin (B) having a melt flow rate of 8.0 g/10 min or less as measured under conditions of 230°C and a 2.16 kg load, A thermoplastic elastomer composition (I) containing 2 to 6 parts by mass of a fatty acid-based lubricant (D) and 80 parts by mass or more of a softening agent (C1), The half-crystallization time of the thermoplastic elastomer composition (I) at 120°C is 200 seconds or less. A thermoplastic elastomer composition (I) wherein the maximum spherulite size of the polyolefin component contained in the thermoplastic elastomer composition (I) is in the range of 8 μm or less. (a1) The weight-average molecular weight is 350,000 or more. (a2) The intrinsic viscosity [η] is 4.0 dL/g or greater. (a3) The ethylene content is 57.0% by mass or more. (a4) The non-conjugated polyene content is 4.0% by mass or more.
  2. The thermoplastic elastomer composition (I) according to claim 1, wherein the crystalline polyolefin (B) is a propylene homopolymer, and the melting point of the crystalline polyolefin (B), as measured by differential calorimetry, is 150 to 170°C.
  3. A molded article comprising the thermoplastic elastomer composition (I) according to claim 1 or 2.
  4. A layer comprising the thermoplastic elastomer composition (I) according to claim 1 or 2, A laminate comprising layers containing a soft material having a Type A hardness of 50 to 95 as measured in accordance with ISO 7619.
  5. The laminate according to claim 4, wherein the hardness of the type A of the soft material is 50 to 85.
  6. The soft material includes a thermoplastic elastomer composition (II) containing a thermoplastic elastomer, The thermoplastic elastomer composition (II) comprises a softener (C2) having a solubility parameter of 6.6 to 7.1. The laminate according to claim 4, wherein the mass fraction (W 2C ) of the softener (C2) relative to the total amount of the thermoplastic elastomer composition (II) is 30 to 60% by mass.
  7. The laminate according to claim 6, wherein the ratio of the mass fraction of the softener (C1) ( W1C ) to the total of the thermoplastic elastomer composition (I) to the ratio of W2C ( W1C / W2C ) is 0.5 or less.
  8. The molded article according to claim 3, which is a window frame seal, a glass run channel, or a building material gasket.
  9. The laminate according to claim 4, which is a window frame seal, a glass run channel, or a building material gasket.
  10. A method for producing a thermoplastic elastomer composition (I), The thermoplastic elastomer composition (I) satisfies the following requirements (X) and (Y), A step (α) to prepare a mixture (α) by kneading an ethylene-α-olefin-non-conjugated polyene copolymer (A) (where the number of carbon atoms in the α-olefin is 3 or more) that satisfies the following requirements (a1) to (a4) with a softening agent (C1), and The mixture (α) and Amount to 100 parts by mass of the copolymer (A): 360 to 460 parts by mass of crystalline polyolefin (B) having a melt flow rate of 8.0 g/10 min or less as measured under conditions of 230°C and a 2.16 kg load, A phenolic resin-based crosslinking agent (E) is provided in 2 to 9 parts by mass, Fatty acid-based lubricant (D) is 2 to 6 parts by mass, The process includes a step (β) of optionally mixing with a softening agent (C1), The total amount of the softener (C1) contained in the mixture (α) and the softener (C1) optionally mixed in step (β) is 80 parts by mass or more. A method for producing a thermoplastic elastomer composition (I), wherein the mass fraction of the softener (C1) contained in the mixture (α) and the softener (C1) optionally mixed in step (β) is 60 to 100% by mass. (X) The half-crystallization time of thermoplastic elastomer composition (I) at 120°C is 200 seconds or less. (Y) The maximum spherulite size of the polyolefin component contained in the thermoplastic elastomer composition (I) is in the range of 8 μm or less. (a1) The weight-average molecular weight is 350,000 or more. (a2) The intrinsic viscosity [η] is 4.0 dL/g or greater. (a3) The ethylene content is 57.0% by mass or more. (a4) The non-conjugated polyene content is 4.0% by mass or more.
  11. A method for producing a thermoplastic elastomer composition (I) according to claim 10, wherein the mass fraction of the softener (C1) contained in the mixture (α) and the softener (C1) optionally mixed in the step (β) is 95 to 100% by mass.
  12. A method for producing a thermoplastic elastomer composition (I) according to claim 10, wherein the step (β) includes a step of dynamically heat-treating the copolymer (A), the crystalline polyolefin (B), the softener (C1 ) , and the fatty acid-based lubricant (D) in the presence of the phenol resin-based crosslinking agent (E).

Description

This invention relates to a thermoplastic elastomer composition and a molded article thereof. As molded articles made of thermoplastic elastomer materials containing rubber components, resin components, etc., multilayer structures are known in which a sliding coating is formed on the surface of the substrate constituting the molded article (for example, in parts requiring sliding properties). An example of such a multilayer molded article is the glass run channel in an automobile. Materials used for sliding coatings in automotive glass run channels are required to possess a good balance of various properties. These properties include, in particular, oil resistance, low oil bleeding at high temperatures (hereinafter also referred to as "heat aging resistance"), hardness, and mechanical strength. Regarding this heat aging resistance, one theory is that when the coating, which is made of a material containing a softening agent, is laminated onto the substrate (glass run channel body), which is also made of a material containing a softening agent, the difference in concentration of the softening agent in the coating and the substrate causes the softening agent (oil) to migrate, resulting in a bleeding phenomenon. Patent Document 1 discloses a thermoplastic elastomer composition that includes a crosslinked product of an ethylene-α-olefin-non-conjugated polyene copolymer (A) (where the number of carbon atoms in the α-olefin is 3 to 20) with a phenolic resin-based crosslinking agent (E), and further includes 360 to 460 parts by mass of crystalline polyolefin (B), 70 to 140 parts by mass of a softener (C), and 2 to 6 parts by mass of a fatty acid-based lubricant (D) per 100 parts by mass of the copolymer (A), thereby exhibiting excellent heat aging resistance, excellent hardness and mechanical properties (tensile modulus, tensile breaking strength), and excellent moldability. International Publication No. 2020/189633 Electron microscope image showing the spherulitic state of the polyolefin component of the composition of Example 1.Electron microscope image showing the spherulitic state of the polyolefin component in the composition of Comparative Example 5. [Thermoplastic elastomer composition (I)] The thermoplastic elastomer composition (I) according to the present invention is The product contains a crosslinked product of an ethylene-α-olefin-non-conjugated polyene copolymer (A) that satisfies the following requirements (a1) to (a4), and a phenolic resin-based crosslinking agent (E), and also contains a crystalline polyolefin (B) with a melt flow rate of 8.0 g/10 min or less measured under conditions of 230°C and a 2.16 kg load, a softener (C1), and a fatty acid-based lubricant (D). The half-crystallization time of the thermoplastic elastomer composition (I) at 120°C is 200 seconds or less. The thermoplastic elastomer composition (I) is characterized in that the maximum spherulite size of the polyolefin component contained in it is in the range of 8 μm or less. (a1) The weight-average molecular weight is 350,000 or more. (a2) The intrinsic viscosity [η] is 4.0 dL/g or greater. (a3) The ethylene content is 57.0% by mass or more. (a4) The non-conjugated polyene content is 4.0% by mass or more. <Ethylene-α-olefin-non-conjugated polyene copolymer (A)> The ethylene-α-olefin-non-conjugated polyene copolymer (A) used in the present invention (hereinafter also simply referred to as "polymer (A)") is an ethylene-α-olefin-non-conjugated polyene copolymer comprising structural units derived from ethylene, structural units derived from at least one α-olefin having 3 or more carbon atoms (preferably 20 or less), and structural units derived from at least one non-conjugated polyene. Examples of the α-olefins include linear α-olefins without side chains such as propylene (3 carbon atoms), 1-butene (4 carbon atoms), 1-nonene (9 carbon atoms), 1-decene (10 carbon atoms), 1-nonadecene (19 carbon atoms), and 1-eicosene (20 carbon atoms); and α-olefins with side chains such as 4-methyl-1-pentene, 9-methyl-1-decene, 11-methyl-1-dodecene, and 12-ethyl-1-tetradecene. These α-olefins may be used individually or in combination of two or more. Among these, α-olefins with 3 to 10 carbon atoms, such as propylene, 1-butene, 1-nonene, and 1-decene, are preferred, and propylene is particularly preferred from the viewpoint of heat resistance. Examples of non-conjugated polyenes include linear non-conjugated dienes such as 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, and 7-methyl-1,6-octadiene; cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinyl-2-norbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, and 5-isopropylidene-2-norbornene. Examples include cyclic non-conjugated dienes such as 6-chloromethyl-5-isopropenyl-2-norbornene; and trienes such as 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2,5-norbornadiene, 1,3,7-octatriene, 1,4,9-decatr