JP2012246329A - Thermoplastic elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer composition excellent in low compression set.SOLUTION: The thermoplastic elastomer composition is obtained by feeding 100 pts.wt. of the total of (A) 10-70 pts.wt. of an ethylene-α-olefin-nonconjugated polyene copolymer rubber and (B) 30-90 pts.wt. of an ethylene-α-olefin-based copolymer rubber and a crosslinking agent to a melt kneader followed by conducting a dynamic heat treatment of components A and B in the presence of the crosslinking agent.

Description

  The present invention relates to a thermoplastic elastomer composition.

Olefin-based thermoplastic elastomer compositions can be processed with ordinary thermoplastic resin molding machines, are recyclable, and are more flexible, so they can be used for automobile interior parts such as console boxes and instrument panel skins, and window moldings. It is used for various parts including automobile exterior parts.
For example, two types of olefinic thermoplastic elastomer compositions obtained by dynamically heat-treating ethylene-propylene-ethylidenenorbornene copolymer rubber and polypropylene resin are blended as olefinic thermoplastic elastomer compositions for skin sheets of automobile interior parts. A composition has been proposed (see, for example, Patent Document 1).

JP-A-6-136205

  However, the thermoplastic elastomer comprising the above composition is not fully satisfactory in terms of low compression strain.

  Under such circumstances, the problem to be solved by the present invention is to provide a thermoplastic elastomer composition excellent in low compression set.

In the present invention, 10 to 70 parts by weight of the following component (A), 30 to 90 parts by weight of the following component (B) (provided that the total of the component (A) and the component (B) is 100 parts by weight) and a crosslinking agent. Is supplied to a melt-kneading apparatus, and a thermoplastic elastomer composition obtained by dynamically heat-treating component (A) and component (B) in the presence of a crosslinking agent.
Component (A): Polypropylene resin component (B): Contains the following rubber component (1), rubber component (2), and optionally a mineral oil-based softener, and comprises rubber component (1) and rubber component (2). The rubber component (1) content is 60 wt% or more and 75 wt% or less, and the rubber component (2) content is 40 wt% or less and 25 wt% or more, with the total being 100 wt%. A rubber in which the total content of 1) and the rubber component (2) is 100 parts by weight, and the content of the mineral oil softener is 0 to 200 parts by weight.
Rubber component (1): The content of monomer units based on ethylene is 50 mol% or more and 80 mol% or less, and the content of monomer units based on α-olefin is 50 mol% or less and 20 mol% or more (however, The total of the monomer units based on ethylene and the monomer units based on α-olefin is 100 mol%.) And an ethylene-α-olefin-nonconjugated polyene copolymer having an iodine value of 2 or more and 45 or less. Polymer rubber component (2): The content of monomer units based on ethylene is more than 80 mol% and 95 mol% or less, the content of monomer units based on α-olefin is less than 20 mol% and 5 mol% or more (However, the total of the monomer unit based on ethylene and the monomer unit based on α-olefin is 100 mol%), the iodine value is 0 or more and 30 or less, and [rubber component (1) Iodine value of rubber-rubber Ethylene-α-olefin copolymer rubber having an iodine value of component (2) of 2 to 30

  According to the present invention, a thermoplastic elastomer composition excellent in low compression set can be provided.

The thermoplastic elastomer composition of the present invention comprises 10 to 70 parts by weight of the following component (A), 30 to 90 parts by weight of the following component (B) (however, the total of the component (A) and the component (B) is 100 parts by weight) And the crosslinking agent are supplied to a melt-kneading apparatus, and the component (A) and the component (B) are dynamically heat-treated in the presence of the crosslinking agent.
Component (A): Polypropylene resin component (B): Contains the following rubber component (1), rubber component (2), and optionally a mineral oil-based softener, and comprises rubber component (1) and rubber component (2). The rubber component (1) content is 60 wt% or more and 75 wt% or less, and the rubber component (2) content is 40 wt% or less and 25 wt% or more, with the total being 100 wt%. A rubber in which the total content of 1) and the rubber component (2) is 100 parts by weight, and the content of the mineral oil softener is 0 to 200 parts by weight.
Rubber component (1): The content of monomer units based on ethylene is 50 mol% or more and 80 mol% or less, and the content of monomer units based on α-olefin is 50 mol% or less and 20 mol% or more (however, The total of the monomer units based on ethylene and the monomer units based on α-olefin is 100 mol%.) And an ethylene-α-olefin-nonconjugated polyene copolymer having an iodine value of 2 or more and 45 or less. Polymer rubber component (2): The content of monomer units based on ethylene is more than 80 mol% and 95 mol% or less, the content of monomer units based on α-olefin is less than 20 mol% and 5 mol% or more (However, the total of the monomer unit based on ethylene and the monomer unit based on α-olefin is 100 mol%), the iodine value is 0 or more and 30 or less, and [rubber component (1) Iodine value of rubber-rubber Ethylene-α-olefin copolymer rubber having an iodine value of component (2) of 2 to 30

(Ingredient (A))
Component (A) is a homopolymer of propylene, or a random copolymer or block copolymer of propylene and ethylene and / or an α-olefin having 4 to 10 carbon atoms, and the content of propylene units Is a polymer having a melting point of 100 ° C. or higher as measured in accordance with JIS K7121 at a rate of temperature increase and rate of temperature decrease of 5 ° C./min. Component (A) may be a combination of two or more of the homopolymer, the random copolymer, and the block copolymer.

  As the above random copolymer, in order to increase the heat resistance of the thermoplastic elastomer composition, (1) the content of propylene units is 90 to 99.5% by weight, and the content of ethylene units is 0.5. Propylene-ethylene random copolymer (the total of propylene units and ethylene units is 100% by weight); (2) the content of propylene units is 90 to 99% by weight and ethylene units The propylene-ethylene-α-olefin random copolymer has a content of 0.5 to 9.5% by weight and a content of α-olefin units having 4 to 10 carbon atoms of 0.5 to 9.5% by weight. A polymer (the total of propylene units, ethylene units and α-olefin units is 100% by weight); or (3) the content of propylene units is 90 to 99.5% by weight, and the number of carbon atoms is 4 to 0 of α- olefin content units propylene -α- olefin random copolymer is 0.5 to 10% by weight (the total of 100 weight% of propylene units and α- olefin units) is preferred.

  The block copolymer is a step (1) of producing a first polymer which is a homopolymer of propylene or a random copolymer of propylene and ethylene and / or α-olefin, and A first polymer and a second polymer produced by a production method comprising the step (2) of producing a second polymer which is a random copolymer of propylene and ethylene and / or an α-olefin in the presence thereof. Content of monomer units other than propylene units contained in the second polymer (that is, content of ethylene units, content of α-olefin units, or ethylene units and α-olefin units) And the content of the monomer unit other than the propylene unit contained in the first polymer.

  In order to increase the heat resistance of the thermoplastic elastomer composition, the block copolymer preferably has a content of monomer units other than propylene units contained in the first polymer of 0 to 10% by weight (first weight). The total content of all monomer units contained in the coalescence is 100% by weight.) More preferably, the content of monomer units other than propylene units contained in the second polymer is 5 to 50% by weight. (The total of all monomer units contained in the second polymer is 100% by weight), more preferably, the content of the second polymer is 5 to 70% by weight (the block copolymer). The amount of coalescence is 100% by weight.).

  Linear α-olefins such as 1-butene, 1-pentene, 1-hexene, 1-octene and 1-decene as the α-olefin having 4 to 10 carbon atoms; 3-methyl-1-butene And branched α-olefins such as 3-methyl-1-pentene; and combinations of two or more thereof.

  The melt flow rate (MFR) of the component (A) measured at 230 ° C. under a load of 21.18 N according to JIS K7210 is preferably 0.1 g / 10 min or more, more preferably 1 g / min in order to improve processability. It is 10 minutes or more, and preferably 150 g / 10 minutes or less, more preferably 100 g / 10 minutes or less, in order to increase the low compression set of the thermoplastic elastomer composition and to increase the strength.

  Examples of component (A) include propylene homopolymer, ethylene-propylene random copolymer, ethylene-propylene-butene random copolymer, ethylene-propylene block copolymer, and ethylene-propylene-butene block copolymer. can do. Among these, a homopolymer of propylene, an ethylene-propylene random copolymer, and an ethylene-propylene block copolymer are preferable.

  As a method for producing the polypropylene resin of component (A) in the present invention, a known Ziegler-Natta catalyst or a known complex catalyst such as a metallocene complex and a nonmetallocene complex is used. Examples of the method include homopolymerization of propylene or copolymerization of propylene and other monomers by known polymerization methods such as a polymerization method, a bulk polymerization method, and a gas phase polymerization method. The component (A) may be a commercially available product.

(Ingredient (B))
A rubber containing the rubber component (1) and the rubber component (2). The α-olefin of the rubber component (1) and the rubber component (2) is preferably an α-olefin having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1 -Linear α-olefins such as octene, 1-nonene and 1-decene; branched α-olefins such as 3-methyl-1-butene, 3-methyl-1-pentene and 4-methyl-1-pentene can give. These may be used alone or in combination of two or more. The α-olefin is preferably propylene or 1-butene, more preferably propylene.

  Examples of the non-conjugated polyene of the rubber component (1) and the rubber component (2) include 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5- Chain non-conjugated dienes such as heptadiene and 7-methyl-1,6-octadiene; cyclohexadiene, dicyclopentadiene, methyltetraindene, 5-vinyl-2-norbornene, 5- (2-propenyl) -2-norbornene, 5- (3-butenyl) -2-norbornene, 5- (4-pentenyl) -2-norbornene, 5- (5-hexenyl) -2-norbornene, 5- (5-heptenyl) -2-norbornene, 5- (7-octenyl) -2-norbornene, 5-methylene-2-norbornene, 5-ethylidene-2-norbornene, 6-chloromethyl-5 Cyclic non-conjugated dienes such as isopropenyl-2-norbornene; 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2,2-norbornadiene, 1, 3,7-octatriene, 1,4,9-decatriene, 6,10-dimethyl-1,5,9-undecatriene, 5,9-dimethyl-1,4,8-decatriene, 4-ethylidene-8 -Methyl-1,7-nonadiene, 13-ethyl-9-methyl-1,9,12-pentadecatriene, 8,14,16-trimethyl-1,7,14-hexadecatriene, 4-ethylidene-12 -Trienes such as methyl-1,11-pentadecadien. These may be used alone or in combination of two or more. The nonconjugated polyene is preferably at least one compound selected from the group of nonconjugated polyenes consisting of 5-ethylidene-2-norbornene, dicyclopentadiene and 5-vinyl-2-norbornene.

  Examples of the rubber component (1) ethylene-α-olefin-nonconjugated polyene copolymer rubber include ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber and ethylene-propylene-dicyclopentadiene copolymer. Rubber, ethylene-propylene-5-vinyl-2-norbornene copolymer rubber, ethylene-1-butene-5-ethylidene-2-norbornene copolymer rubber, ethylene-1-butene-dicyclopentadiene copolymer rubber, Mention may be made of ethylene-1-butene-5-vinyl-2-norbornene copolymer rubber.

  The content of the monomer unit (ethylene unit) based on ethylene of the rubber component (1) is 50 to 80 mol%, and the content of the monomer unit (α-olefin unit) based on the α-olefin is 50. The mol% is 20 mol% or less. In order to increase the low compression set and to increase the strength, the ethylene unit content is preferably 55 mol% or more and 79 mol% or less, and the α-olefin unit content is 45 mol% or less 21 mol. More preferably, the ethylene unit content is 60 mol% or more and 78 mol% or less, and the α-olefin unit content is 40 mol% or less and 22 mol% or more. However, the total of the ethylene unit content and the α-olefin unit content is 100 mol%.

  The iodine value (g / 100 g polymer) of the rubber component (1) is 4 or more and 45 or less. In order to enhance the low compression set, it is preferably 6 or more, more preferably 8 or more. Moreover, in order to improve a weather resistance, Preferably it is 40 or less, More preferably, it is 35 or less.

  Examples of the rubber component (2) ethylene-α-olefin copolymer rubber include ethylene-α-olefin copolymer rubber and ethylene-α-olefin-nonconjugated polyene copolymer rubber. Examples of the ethylene-α-olefin copolymer rubber include ethylene-propylene copolymer rubber, ethylene-1-butene copolymer rubber, ethylene-1-hexene copolymer rubber, and ethylene-1-octene copolymer. Examples thereof include rubber, ethylene-propylene-1-butene copolymer rubber, and ethylene-propylene-1-hexene copolymer rubber. Examples of the ethylene-α-olefin-nonconjugated polyene copolymer rubber include ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber, ethylene-propylene-dicyclopentadiene copolymer rubber, and ethylene-propylene- 5-vinyl-2-norbornene copolymer rubber, ethylene-1-butene-5-ethylidene-2-norbornene copolymer rubber, ethylene-1-butene-dicyclopentadiene copolymer rubber, ethylene-1-butene- Examples thereof include 5-vinyl-2-norbornene copolymer rubber.

  The rubber unit (2) has an ethylene unit content of more than 80 mol% and 95 mol% or less, and an α-olefin unit content of less than 20 mol% and 5 mol% or more. In order to increase the low compression set and to increase the rigidity, the ethylene unit content is preferably 81 mol% or more and 92 mol% or less, and the α-olefin unit content is 19 mol% or less and 8 mol%. More preferably, the ethylene unit content is 82 mol% or more and 90 mol% or less, and the α-olefin unit content is 18 mol% or less and 10 mol% or more. However, the total of the ethylene unit content and the α-olefin unit content is 100 mol%.

  The iodine value (g / 100 g polymer) of the rubber component (2) is 0 or more and 30 or less. In order to enhance the low compression set, it is preferably 1 or more, more preferably 2 or more. Moreover, in order to improve a weather resistance, Preferably it is 27 or less, More preferably, it is 25 or less.

  The value of [iodine value of rubber component (1) −iodine value of rubber component (2)] is 2 or more and 30 or less. The value is preferably 3 or more, more preferably 4 or more, in order to increase rigidity. Further, the value is preferably 25 or less, more preferably 20 or less, in order to enhance the low compression set.

  The content of the rubber component (1) in the component (B) is 60 wt% or more and 75 wt% or less, and the content of the rubber component (2) is 40 wt% or less and 25 wt% or more. Preferably, the rubber component (1) content is 62 wt% or more and 74 wt% or less, and the rubber component (2) content is 38 wt% or less and 26 wt% or more.

  The intrinsic viscosity [η] of the rubber component consisting of the rubber component (1) and the rubber component (2) in the component (B) is preferably 1 dl / in order to increase the low compression set and increase the strength. g or more, more preferably 1.5 dl / g or more, and still more preferably 1.8 dl / g or more. Further, it is preferably 10 dl / g or less, more preferably 8 dl / g or less, and further preferably 5 dl / g or less. The intrinsic viscosity [η] is measured at 135 ° C. in tetralin.

  The iodine value (g / 100 g polymer) of the rubber component comprising the rubber component (1) and the rubber component (2) in the component (B) is preferably 1 to 39, more preferably 3 to 37, Preferably it is 4-33.

  The molecular weight distribution of the rubber component comprising the rubber component (1) and the rubber component (2) in the component (B) (ratio of polystyrene-equivalent Z average molecular weight (Mz) to number average molecular weight (Mn): Mz / Mw) is In order to improve the kneading processability and kneading workability, it is preferably 2-7. The molecular weight distribution is preferably unimodal in order to increase the strength.

  As a method for producing the rubber component (1) and the rubber component (2), it is preferable to use two reaction tanks connected in series in order to enhance the appearance of a molded article made of a thermoplastic elastomer composition. Either one of (1) and the rubber component (2) is produced in the first reaction tank, and the copolymer rubber produced in the first reaction tank is supplied to the second reaction tank. In the presence, a method of producing the other copolymer rubber in the second reaction tank can be mentioned. For example, ethylene, α-olefin, non-conjugated polyene, solvent, hydrogen and polymerization catalyst are supplied to the first reaction tank, and either one of the rubber component (1) and the rubber component (2) is produced in the first reaction tank. The copolymer rubber, ethylene, α-olefin, non-conjugated polyene, solvent, hydrogen and polymerization catalyst produced in the first reaction tank are supplied to the second reaction tank, and the other copolymer rubber is supplied to the second reaction tank. The method of manufacturing with a tank is mention | raise | lifted.

  Examples of the catalyst used in the production of the rubber component (1) and the rubber component (2) in the present invention include known Ziegler-Natta catalysts or known complex catalysts such as metallocene complexes and nonmetallocene complexes. be able to.

As a polymerization catalyst used for production of the rubber component (1), a vanadium compound represented by the following general formula (1) and an organoaluminum compound represented by the following general formula (2) are preferably used as the polymerization catalyst component. The polymerization catalyst.
General formula (1)
VO (OR) _m X _3-m (wherein R represents a linear hydrocarbon group having 1 to 8 carbon atoms, X represents a halogen atom, and m represents a number satisfying 0 ≦ m ≦ 3) To express.)
General formula (2)
R ″ _j AlX ″ _3-j (wherein R ″ represents a hydrocarbon group, X ″ represents a halogen atom, and j represents a number satisfying 0 <j ≦ 3).

  In the general formula (1), R represents a linear hydrocarbon group having 1 to 8 carbon atoms, for example, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n- Examples thereof include straight-chain alkyl groups having 1 to 8 carbon atoms such as hexyl group. Preferably, it is a linear alkyl group having 1 to 3 carbon atoms. X represents a halogen atom, and examples thereof include a chlorine atom. M represents a number satisfying 0 ≦ m ≦ 3, and preferably a number satisfying 0 ≦ m ≦ 2.

Examples of the vanadium compound represented by the general formula (1) include VOCl ₃ , VO (OCH ₃ ) Cl ₂ , VO (OC ₂ H ₅ ) Cl ₂ , VO (O (n—C ₃ H ₇ )) Cl ₂ , _{VO (O (n-C 4} H 9)) Cl 2, VO (O (n-C 5 H 11)) Cl 2, VO (O (n-C 6 H 13)) Cl 2, VO (O (n _{-C 7 H 15)) Cl 2} , VO (O (n-C 8 H 17)) Cl 2, VO (OCH 3) 0.5 Cl 2.5, VO (OC 2 H 5) 0.5 Cl 2.5, VO (O (n _{-C 3 H 7)) 0.5 Cl} 2.5, VO (O (n-C 4 H 9)) 0.5 Cl 2.5, VO (O (n-C 5 H 11)) 0.5 Cl 2.5, VO (O (n-C _{6 H 13)) 0.5 Cl 2.5} , VO (O (n-C 7 H 15)) 0.5 Cl 2.5, VO (O (n-C 8 H 17)) 0.5 Cl 2.5, VO (OCH 3) 1.5 Cl 0.5, VO (OC ₂ H ₅ ) _1.5 Cl _0.5 , VO (O (n—C ₃ H ₇ )) _1.5 C l _0.5 , VO (O (n—C ₄ H ₉ )) _1.5 Cl _0.5 , VO (O (n—C ₅ H ₁₁ )) _1.5 Cl _0.5 , VO (O (n—C ₆ H ₁₃ )) _1.5 Cl _0.5 , VO (O (n-C 7 H 15)) 1.5 Cl 0.5, VO (O (n-C 8 H 17)) 1.5 Cl 0.5, VO (OCH 3) 0.8 Cl 2.2, VO (OC 2 H 5) 0.8 Cl _2.2 , VO (O (n—C ₃ H ₇ )) _0.8 Cl _2.2 , VO (O (n—C ₄ H ₉ )) _0.8 Cl _2.2 , VO (O (n—C ₅ H ₁₁ )) _0.8 Cl _2.2 , VO (O (n-C 6 H 13)) 0.8 Cl 2.2, VO (O (n-C 7 H 15)) 0.8 Cl 2.2, the _{VO (O (n-C 8} H 17)) 0.8 Cl 2.2 , etc. I can give you. Preferably, VOCl ₃ , VO (OC ₂ H ₅ ) Cl ₂ , VO (OC ₂ H ₅ ) _0.5 Cl _2.5 , VO (OC ₂ H ₅ ) _1.5 Cl _0.5 , VO (OC ₂ H ₅ ) _0.8 Cl _2.2 .

The vanadium compound represented by the general formula (1) is obtained by a method in which VOX ₃ and ROH are reacted at a predetermined molar ratio. For example, the reaction between VOCl ₃ and C ₂ H ₅ OH is represented by the following formula.
VOCl ₃ + m · C ₂ H ₅ OH → VO (OC ₂ H ₅ ) _m Cl _3-m + m · HCl

  In the general formula (2), R ″ represents a hydrocarbon group, for example, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a pentyl group, a hexyl group, etc. And an alkyl group having 1 to 10 carbon atoms, X ″ represents a halogen atom, such as a chlorine atom. J represents a number satisfying 0 <j ≦ 3, and preferably a number satisfying 1 ≦ m ≦ 2.

Examples of the organoaluminum compound represented by the general formula (2) include (C ₂ H ₅ ) ₂ AlCl, (n-C ₄ H ₉ ) ₂ AlCl, (iso-C ₄ H ₉ ) ₂ AlCl, (n-C ₆ H ₁₃ ) ₂ AlCl, (n-C ₂ H ₅ ) _1.5 AlCl _1.5 , (n-C ₄ H ₉ ) _1.5 AlCl _1.5 , (iso-C ₄ H ₉ ) _1.5 AlCl _1.5 , (n-C ₆ H ₁₃ ) _1.5 AlCl _1.5 , C ₂ H ₅ AlCl ₂ , (n—C ₄ H ₉ ) AlCl ₂ , (iso-C ₄ H ₉ ) AlCl ₂ , (n—C ₆ H ₁₃ ) AlCl _{2 and the} like can be exemplified.

As a polymerization catalyst used for production of the rubber component (2), a vanadium compound represented by the following general formula (3) and an organoaluminum compound represented by the above general formula (2) are preferably used as the polymerization catalyst component. The polymerization catalyst.
General formula (3)
VO (OR ′) _n X ′ _3-n (wherein R ′ represents a secondary or tertiary hydrocarbon group having 3 to 8 carbon atoms, X ′ represents a halogen atom, and n is 0 < It represents the number that satisfies n ≦ 3.)

  In the general formula (3), R ′ represents a secondary or tertiary hydrocarbon group having 3 to 8 carbon atoms, for example, a carbon atom such as an iso-propyl group, a sec-butyl group, or a tert-butyl group. Examples thereof include secondary or tertiary alkyl groups of 3 to 8. Preferably, it is a secondary or tertiary alkyl group having 3 to 4 carbon atoms. X ′ represents a halogen atom, and examples thereof include a chlorine atom. N represents a number satisfying 0 <n ≦ 3, and preferably 0.5 <n ≦ 2.

Examples of the vanadium compound represented by the general formula (3) include VO (O (iso-C ₃ H ₇ )) Cl ₂ , VO (O (iso-C ₃ H ₇ )) _0.5 Cl _2.5 , VO (O (iso -C ₃ H ₇ )) _1.5 Cl _0.5 , VO (O (iso-C ₃ H ₇ )) _0.8 Cl _{2.2 and the} like. Preferably, VO (O (iso-C 3 H 7)) is _0.8 Cl _2.2.

The vanadium compound represented by the general formula (3) is obtained by a method in which VOX ′ ₃ and R′OH are reacted at a predetermined molar ratio. For example, the reaction between VOCl ₃ and iso-C ₃ H ₇ OH is represented by the following formula.
VOCl ₃ + n · iso-C ₃ H ₇ OH
→ VO (O (iso-C 3 H 7) n Cl 3-n + n · HCl

  In the production of the rubber component (1) and the rubber component (2), the molar ratio between the amount of the organoaluminum compound used and the amount of the vanadium compound used (mole of the organoaluminum compound / mol of the vanadium compound) is preferably 2 .5-50.

  As the solvent, an inert solvent such as aliphatic hydrocarbons such as propane, butane, isobutane, pentane, hexane, heptane, and octane; and alicyclic hydrocarbons such as cyclopentane and cyclohexane can be used.

  The polymerization temperature is usually from -20 to 200 ° C, preferably from 0 to 150 ° C, more preferably from 20 to 120 ° C. The polymerization pressure is usually 0.1 to 10 MPa, preferably 0.1 to 5 MPa, and more preferably 0.1 to 3 MPa.

  The component (B) may be an oil-extended rubber extended with a mineral oil-based softening agent. When component (B) is an oil-extended rubber, the content of the mineral oil softener in component (B) is 100 parts by weight of the total of rubber component (1) and rubber component (2). In order to improve the low compression set, it is preferably 20 parts by weight or more, more preferably 22 parts by weight or more, and further preferably 24 parts by weight or more. Further, the content of the mineral oil softener is preferably 200 parts by weight or less, more preferably 180 parts by weight or less, and further preferably 160 parts by weight or less in order to increase the strength. Here, examples of the mineral oil softener include those used in the component (C) described later.

  The amount of component (A) and component (B) subjected to dynamic heat treatment is 10 to 70 parts by weight of component (A), with the total of component (A) and component (B) being 100 parts by weight. The amount of (B) is 30 to 90 parts by weight. In order to enhance fluidity, the amount of component (A) is preferably 12 parts by weight or more (the amount of component (B) is 88 parts by weight or less), more preferably the amount of component (A) is 14 parts by weight. Above (the amount of the component (B) is 86 parts by weight or less). In order to enhance the low compression set, the amount of the component (A) is preferably 60 parts by weight or less (the amount of the component (B) is 40 parts by weight or more), more preferably the component (A). The amount is 50 parts by weight or less (the amount of component (B) is 50 parts by weight or more).

(Ingredient (C))
Component (C) is a mineral oil softener. Examples of component (C) include high-boiling fractions (average molecular weight of 300 to 1500, pour point of 0 ° C. or lower) of petroleum such as aroma mineral oil, naphthenic mineral oil, and paraffin mineral oil. Of these, paraffinic mineral oil is preferred.

  In addition to component (A) and component (B), component (C) is supplied to the melt-kneading apparatus, and component (A), component (B) and component (C) are dynamically added in the presence of a crosslinking agent. You may heat-process. The amount of the component (C) supplied to the melt-kneading apparatus is preferably 2 parts by weight or more, and more preferably 2 parts by weight or more in order to improve fluidity, with the total amount of the component (A) and the component (B) being 100 parts by weight. Is 4 parts by weight or more, more preferably 8 parts by weight or more. Further, in order to enhance the low compression set, and in order to enhance the appearance of the molded article made of the thermoplastic elastomer composition, it is preferably 60 parts by weight or less, more preferably 50 parts by weight or less, The amount is preferably 40 parts by weight or less.

(Crosslinking agent / Crosslinking aid)
Examples of the crosslinking agent include organic peroxides, sulfur compounds and alkylphenol resins. Of these, organic peroxides are preferred.

  Organic peroxides include known ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peresters, percarbonates, peroxydicarbonates, and peroxydicarbonates. Oxyesters can be exemplified. Specific organic peroxides include dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxide). Oxy) hexyne, 1,3-bis (t-butylperoxyisopropyl) benzene, t-butylcumyl peroxide, di-t-butyl peroxide, 2,2,4-trimethylpentyl-2-hydroperoxide, diisopropyl Benzohydroperoxide, cumene peroxide, t-butyl peroxide, 1,1-di (t-butylperoxy) 3,5,5-trimethylcyclohexane, 1,1-di-t-butylperoxycyclohexane, isobutyl Peroxide, 2,4-dichlorobenzoyl peroxide, o-methylbenzoyl peroxide , Bis-3,5,5-trimethyl hexanoyl peroxide, lauroyl peroxide, benzoyl peroxide, and p- chlorobenzoyl peroxide; and can be a combination of two or more thereof.

  The amount of the crosslinking agent is preferably 0.01 wt.% In order to increase the strength and to increase the low compression set, with the total amount of component (A), component (B) and component (C) being 100 parts by weight. Part or more, more preferably 0.05 part by weight or more, and still more preferably 0.1 part by weight or more. Further, the amount of the crosslinking agent is preferably 10 parts by weight or less, more preferably 2 parts by weight or less, and still more preferably 1 part by weight or less in order to improve fluidity.

  The cross-linking agent may be combined with a cross-linking aid in order to improve the cross-linking degree of the produced thermoplastic elastomer composition. A preferred crosslinking aid is a compound having two or more double bonds. N, N-m-phenylene bismaleimide, toluylene bismaleimide, p-quinone dioxime, nitrosobenzene, diphenylguanidine, trimethylolpropane, trimethylolpropane trimethacrylate, and divinylbenzene as crosslinking aids; and these Two or more combinations can be exemplified.

  The amount of the crosslinking aid is preferably 0.01 in order to increase the strength and to increase the low compression set, with the total amount of component (A), component (B) and component (C) being 100 parts by weight. In order to improve fluidity, the amount is preferably 10 parts by weight or less.

(Thermoplastic elastomer composition)
The thermoplastic elastomer composition of the present invention supplies component (A), component (B), a crosslinking agent, and optionally component (C) to a melt-kneading apparatus, and the components (A), (B) It is a composition obtained by dynamically heat-treating component (C) as necessary in the presence of a crosslinking agent. The dynamic heat treatment means that the crosslinking reaction is performed at a temperature suitable for the crosslinking reaction while melt-mixing all or some of the components of the composition of the present invention. Examples of the melt-kneading apparatus used for the dynamic heat treatment include known apparatuses such as a twin-screw extruder and a Banbury mixer. For similar treatments, the term dynamic crosslinking is also used. Details of these methods are described in documents such as Thermoplastic Elastomers 2nd. Ed., 153-190 (Hanser Gardner Publications, 1996).

  The dynamic heat treatment temperature is usually 150 to 250 ° C., and the dynamic heat treatment time is usually 1 to 30 minutes. In the melt kneading of the dynamic heat treatment, all components to be kneaded may be melt kneaded all at once, or some components not selected after kneading some components may be added and melt kneaded. May be used once or more than once. Preferably, a method of melting and kneading all the components to be kneaded together is preferable.

  The thermoplastic elastomer composition of the present invention comprises an inorganic filler (for example, talc, calcium carbonate and calcined kaolin), an organic filler (for example, fiber, wood powder and cellulose powder), an antioxidant (for example, phenol-based, sulfur-based, Phosphorus, lactone and vitamins), weathering stabilizers, UV absorbers (eg benzotriazoles, tridiamines, anilides and benzophenones), heat stabilizers, light stabilizers (eg hindered amines and benzoates) , Antistatic agents, nucleating agents, pigments, adsorbents (eg metal oxides such as zinc oxide and magnesium oxide), metal chlorides (eg iron chloride and calcium chloride), hydrotalcite, aluminates, Lubricants (eg fatty acids, higher alcohols, aliphatic amides, aliphatic esters) It may contain additives such as silicone compounds beauty. The additive may be added to either component (A) or component (B) in advance, or may be prepared in advance before preparing the thermoplastic elastomer composition. If necessary, component (A) and component (B) may be used. The component (C) may be added after the dynamic heat treatment or during the dynamic heat treatment.

  The amount of the additive is preferably 100 parts by weight of the total of the component (A), the component (B), and the component (C) from the viewpoint of demolding property, abrasion resistance, and scratch resistance. 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight.

  The melt flow rate (MFR) of the thermoplastic elastomer composition is usually 0.1 to 150 g / 10 minutes, preferably 0.5 to 100 g / 10 minutes.

  The thermoplastic elastomer composition of the present invention is excellent in low compression set. Moreover, fluidity | liquidity and intensity | strength are also favorable.

  The thermoplastic elastomer composition of the present invention is suitably used for automotive interior parts such as console boxes and instrument panel skins, automotive exterior parts such as window moldings, home appliances, and furniture.

  Hereinafter, the present invention will be described in more detail by way of examples and comparative examples.

[I] Rubber Evaluation Method (1) Amount of ethylene units / amount of propylene Units were measured by infrared absorption spectroscopy.
(2) Iodine value It measured by the infrared absorption spectrum method.
(3) Weight average molecular weight It measured and calculated | required by the following conditions (A)-(H) using the gel permeation chromatograph (GPC) method.
(A) Apparatus: Waters 150C manufactured by Water
(B) Separation column: TOSOH TSKgelGMH6-HT
(C) Measurement temperature: 140 ° C
(D) Carrier: Orthodichlorobenzene (E) Flow rate: 1.0 mL / min (F) Injection volume: 500 μL
(G) Detector: Differential refraction (H) Molecular weight standard substance: Standard polystyrene

[II] Physical property measurement method (1) Melt flow rate (MFR)
According to JIS K7210, the load was 98.07 N and the temperature was 230 ° C.
(2) Hardness A hardness was measured according to JIS K6253.
(3) Tensile test In accordance with JIS K6251, the tensile strength at break and the tensile elongation at break were determined under the conditions of JIS No. 3 dumbbell and tensile speed of 200 mm / min.
(4) Compression set According to JIS K6262, compression set was measured under the conditions of 70 ° C., 22 hours, 25% compression.

Example 1
(Manufacture of oil-extended rubber)
In a first polymerization tank made of stainless steel equipped with a stirrer and maintained at 45 ° C., 0.755 kg / (hr · L) of hexane and 41.8 g of ethylene per unit time / unit volume of the first polymerization tank / (Hr · L), propylene was supplied at a rate of 89.5 g / (hr · L). VOCl ₃ was supplied to the first polymerization tank at a rate of 29.1 mg / (hr · L) and ethanol at 14.0 mg / (hr · L) (VOCl ₃ /ethanol=1/1.8 (molar ratio)). did. VOCl ₃ and ethanol were mixed and stirred with a line mixer before being supplied to the polymerization tank. Further, ethylaluminum sesquichloride (EASC) was supplied to the first polymerization tank at a rate of 166 mg / (hr · L) and hydrogen at a rate of 0.050 NL / (hr · L). Further, 5-ethylidene-2-norbornene was supplied to the first polymerization tank at a rate of 3.5 g / (hr · L).
The polymerization solution was extracted from the first polymerization tank so that the amount of the polymerization solution in the polymerization tank was constant. As a result of analyzing the polymerization solution withdrawn from the first polymerization tank, 40 g / (hr · L) copolymer rubber per unit time / unit volume of the first polymerization tank was generated in the first polymerization tank. It was. The copolymer rubber had an ethylene unit amount / propylene unit amount (molar ratio) of 75/25 and an iodine value of 11 (g / 100 g rubber).

The polymerization solution extracted from the first polymerization tank was fed to a second polymerization tank having a stainless steel temperature of 60 ° C. equipped with a stirrer having the same volume as the first polymerization tank. Per unit time / unit volume of the second polymerization tank, hexane was supplied to the second polymerization tank at a rate of 0.423 kg / (hr · L) and ethylene at 18.0 g / (hr · L). VO (O (iso-C ₃ H ₇ )) _0.8 Cl _2.2 was fed to the second polymerization tank at a rate of 9.7 mg / (hr · L). Further, ethylaluminum sesquichloride (EASC) was supplied to the second polymerization tank at a rate of 34 mg / (hr · L) and hydrogen at a rate of 0.080 NL / (hr · L).
The polymerization solution was extracted from the second polymerization tank so that the amount of the polymerization solution in the polymerization tank was constant. As a result of analyzing the polymerization solution extracted from the second polymerization tank, the content of the copolymer rubber in the polymerization solution was 55 g / (hr · L) per unit time / unit volume of the second polymerization tank. there were.
30 parts by weight of paraffinic mineral oil (Diana PW380 manufactured by Idemitsu Kosan Co., Ltd.) per 100 parts by weight of copolymer rubber in the polymerization solution is added to the polymerization solution extracted from the second polymerization tank, and polymerization is performed from the polymerization solution. The solvent was removed to prepare an oil-extended rubber (hereinafter referred to as EPDM-1).
When EPDM-1 was analyzed, the ethylene unit amount / propylene unit amount (molar ratio) of the copolymer rubber in EPDM-1 was 77/23, and the iodine value was 10 (g / 100 g rubber). The viscosity was 3.1 dl / g and the molecular weight distribution was 2.2.
In the second polymerization tank, 15 g / (hr · L) of copolymer rubber is produced per unit time / unit volume of the second polymerization tank, and ethylene unit amount / propylene unit amount (molar ratio) of the copolymer rubber. ) Was 83/17, and the iodine value was found to be 7 (g / 100 g rubber).

(Production of thermoplastic elastomer composition)
Polypropylene resin [Nobrene D101 manufactured by Sumitomo Chemical Co., Ltd., MFR (230 ° C., 21.18N) = 0.4 g / 10 min]: 15 parts by weight, EPDM-1: 58.5 parts by weight, trimethylolpropane trimethacrylate: 0.2 part by weight, 3,9-bis [1,1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] -2 as an antioxidant , 4,8,10-tetraoxaspiro [5,5] -undecane: 0.1 part by weight, 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chloro as an ultraviolet absorber Benzotriazole: 0.2 parts by weight, and 1- (2-hydroxyethyl) -2,2,6,6-tetramethyl-4-piperidinol / dimethyl succinate polycondensate: 0.2 Was put into a twin screw extruder with an inner diameter of 47 mm, paraffinic mineral oil (Diana PW380, manufactured by Idemitsu Kosan Co., Ltd.): 26.5 parts by weight, an organic peroxide solution [trade name “APO-10DL, manufactured by Kayaku Akzo Co., Ltd.” (2,5-dimethyl-2,5-di (t-butylperoxy) hexane diluted to 10% with paraffinic mineral oil (Diana PW100 manufactured by Idemitsu Kosan Co., Ltd.)): 3.2 parts by weight The thermoplastic elastomer composition was added through separate inlets in the middle of the shaft extruder and subjected to dynamic heat treatment under conditions of an extruder temperature of 200 ± 10 ° C. and a screw speed of 270 rpm downstream from the cross-linking agent supply section. The obtained composition was molded and measured for physical properties, and the results are shown in Table 1.

Comparative Example 1
(Manufacture of oil-extended rubber)
In a first polymerization tank made of stainless steel equipped with a stirrer and maintained at 45 ° C., 0.332 kg / (hr · L) of hexane and 22.5 g of ethylene per unit time / unit volume of the first polymerization tank / (Hr · L), propylene was fed at a rate of 59.8 g / (hr · L). VOCl ₃ was supplied to the first polymerization tank at 15.2 mg / (hr · L). Further, ethylaluminum sesquichloride (EASC) was supplied to the first polymerization tank at a rate of 91.3 mg / (hr · L) and hydrogen at a rate of 0.047 NL / (hr · L). Further, 5-ethylidene-2-norbornene was supplied to the first polymerization tank at a rate of 0.82 g / (hr · L).
The polymerization solution was extracted from the first polymerization tank so that the amount of the polymerization solution in the polymerization tank was constant. As a result of analyzing the polymerization solution withdrawn from the first polymerization tank, 24 g / (hr · L) copolymer rubber per unit time / unit volume of the first polymerization tank was produced in the first polymerization tank. It was. The copolymer rubber had an ethylene unit amount / propylene unit amount (molar ratio) of 79/21 and an iodine value of 12 (g / 100 g rubber).

The polymerization solution extracted from the first polymerization tank was fed into a second polymerization tank having a stainless steel temperature maintained at 45 ° C. equipped with a stirrer having the same volume as the first polymerization tank. Per unit time per unit volume of the second polymerization tank at a rate of 0.151 kg / (hr · L) of hexane, 14.1 g / (hr · L) of ethylene and 53.0 g / (hr · L) of propylene It supplied to the 2nd polymerization tank. VOCl ₃ was fed to the second polymerization tank at a rate of 7.4 mg / (hr · L). Ethyl aluminum sesquichloride (EASC) was supplied to the second polymerization tank at a rate of 44 mg / (hr · L).
The polymerization solution was extracted from the second polymerization tank so that the amount of the polymerization solution in the polymerization tank was constant. As a result of analyzing the polymerization solution withdrawn from the second polymerization tank, the content of the copolymer rubber in the polymerization solution was 36 g / (hr · L) per unit time / unit volume of the second polymerization tank. there were.
40 parts by weight of paraffinic mineral oil (Diana PW380 manufactured by Idemitsu Kosan Co., Ltd.) per 100 parts by weight of copolymer rubber in the polymerization solution is added to the polymerization solution extracted from the second polymerization tank, and polymerization is performed from the polymerization solution. The solvent was removed to prepare an oil-extended rubber (hereinafter referred to as EPDM-2).
When EPDM-2 was analyzed, the ethylene unit amount / propylene unit amount (molar ratio) of the copolymer rubber in EPDM-2 was 79/21, and the iodine value was 12 (g / 100 g rubber). The viscosity was 2.5 dl / g and the molecular weight distribution was 2.1.
In the second polymerization tank, 12 g / (hr · L) of copolymer rubber is produced per unit time / unit volume of the second polymerization tank, and the ethylene unit amount / propylene unit amount (molar ratio) of the copolymer rubber. ) Was 79/21, and the iodine value was found to be 12 (g / 100 g rubber).

(Production of thermoplastic elastomer composition)
The composition of the thermoplastic elastomer of Example 1 except that EPDM-1 is changed to 58.5 parts by weight, EPDM-2 is changed to 63 parts by weight, and paraffinic mineral oil is changed to 26.5 parts by weight to 22 parts by weight. It carried out like manufacture of a thing. The results are shown in Table 1.

Comparative Example 2
(Manufacture of oil-extended rubber)
In a first polymerization tank made of stainless steel equipped with a stirrer and maintained at a temperature of 50 ° C., 0.220 kg / (hr · L) of hexane and 28.6 g of ethylene per unit time / unit volume of the first polymerization tank / (Hr · L), propylene was supplied at a rate of 70.2 g / (hr · L). VOCl ₃ was supplied to the first polymerization tank at 33.3 mg / (hr · L). Further, ethylaluminum sesquichloride (EASC) was supplied to the first polymerization tank at a rate of 200 mg / (hr · L) and hydrogen at a rate of 0.087 NL / (hr · L). Further, 5-ethylidene-2-norbornene was supplied to the first polymerization tank at a rate of 1.1 g / (hr · L).
The polymerization solution was extracted from the first polymerization tank so that the amount of the polymerization solution in the polymerization tank was constant. As a result of analyzing the polymerization solution withdrawn from the first polymerization tank, 34 g / (hr · L) copolymer rubber per unit time / unit volume of the first polymerization tank was formed in the first polymerization tank. It was. The copolymer rubber had an ethylene unit amount / propylene unit amount (molar ratio) of 78/22 and an iodine value of 12 (g / 100 g rubber).

The polymerization solution extracted from the first polymerization tank was fed into a second polymerization tank having a stainless steel temperature of 58 ° C. equipped with a stirrer having the same volume as the first polymerization tank. Per unit time per unit volume of the second polymerization tank, hexane is 0.094 kg / (hr · L), ethylene is 17.3 g / (hr · L), and propylene is 60.4 g / (hr · L). It supplied to the 2nd polymerization tank. VOCl ₃ was fed to the second polymerization tank at a rate of 29.1 mg / (hr · L). Ethyl aluminum sesquichloride (EASC) was supplied to the second polymerization tank at a rate of 87 mg / (hr · L).
The polymerization solution was extracted from the second polymerization tank so that the amount of the polymerization solution in the polymerization tank was constant. As a result of analyzing the polymerization solution extracted from the second polymerization tank, the content of the copolymer rubber in the polymerization solution was 51 g / (hr · L) per unit time / unit volume of the second polymerization tank. there were.
50 parts by weight of paraffinic mineral oil (Diana PW380 manufactured by Idemitsu Kosan Co., Ltd.) per 100 parts by weight of copolymer rubber in the polymerization solution is added to the polymerization solution extracted from the second polymerization tank, and polymerization is performed from the polymerization solution. The solvent was removed to prepare an oil-extended rubber (hereinafter referred to as EPDM-3).
When EPDM-3 was analyzed, the ethylene unit amount / propylene unit amount (molar ratio) of the copolymer rubber in EPDM-3 was 78/22, and the iodine value was 12 (g / 100 g rubber). The viscosity was 1.9 dl / g and the molecular weight distribution was 2.7.
In the second polymerization tank, 17 g / (hr · L) of copolymer rubber is produced per unit time / unit volume of the second polymerization tank, and the ethylene unit amount / propylene unit amount (molar ratio) of the copolymer rubber. ) Was 78/22, and the iodine value was found to be 12 (g / 100 g rubber).

(Production of thermoplastic elastomer composition)
EPDM-1: 58.5 parts by weight EPDM-3: 60 parts by weight, polypropylene resin: 15 parts by weight, 20 parts by weight, paraffinic mineral oil: 26.5 parts by weight, 20 parts by weight Except for the parts, the same procedure as in the production of the thermoplastic elastomer composition of Example 1 was performed. The results are shown in Table 1.

Comparative Example 3
(Manufacture of copolymer rubber)
A copolymer rubber (hereinafter referred to as EPDM-4) was prepared in the same manner as in the production of the oil-extended copolymer rubber of Comparative Example 2 except that no paraffinic mineral oil was added to the polymerization solution. .

(Production of thermoplastic elastomer composition)
EPDM-1: 58.5 parts by weight EPDM-4: 40 parts by weight, polypropylene resin: 20 parts by weight, paraffinic mineral oil: 26.5 parts by weight, 40 parts by weight Except for the parts, the same procedure as in the production of the thermoplastic elastomer composition of Example 1 was performed. The results are shown in Table 1.

Claims (6)

Melting and kneading apparatus comprising 10 to 70 parts by weight of the following component (A), 30 to 90 parts by weight of the following component (B) (provided that the total of component (A) and component (B) is 100 parts by weight) and a crosslinking agent. A thermoplastic elastomer composition obtained by dynamically heat-treating component (A) and component (B) in the presence of a crosslinking agent.
Component (A): Polypropylene resin component (B): Contains the following rubber component (1), rubber component (2), and optionally a mineral oil-based softener, and comprises rubber component (1) and rubber component (2). The rubber component (1) content is 60 wt% or more and 75 wt% or less, and the rubber component (2) content is 40 wt% or less and 25 wt% or more, with the total being 100 wt%. A rubber in which the total content of 1) and the rubber component (2) is 100 parts by weight, and the content of the mineral oil softener is 0 to 200 parts by weight.
Rubber component (1): The content of monomer units based on ethylene is 50 mol% or more and 80 mol% or less, and the content of monomer units based on α-olefin is 50 mol% or less and 20 mol% or more (however, The total of the monomer units based on ethylene and the monomer units based on α-olefin is 100 mol%.) And an ethylene-α-olefin-nonconjugated polyene copolymer having an iodine value of 2 or more and 45 or less. Polymer rubber component (2): The content of monomer units based on ethylene is more than 80 mol% and 95 mol% or less, the content of monomer units based on α-olefin is less than 20 mol% and 5 mol% or more (However, the total of the monomer unit based on ethylene and the monomer unit based on α-olefin is 100 mol%), the iodine value is 0 or more and 30 or less, and [rubber component (1) Iodine value of rubber-rubber Ethylene-α-olefin copolymer rubber having an iodine value of component (2) of 2 to 30   The thermoplastic elastomer composition according to claim 1, wherein the component (B) is an oil-extended rubber having a mineral oil softener content of 20 to 200 parts by weight. The total amount of the component (A) and the component (B) is 100 parts by weight, and 2 to 60 parts by weight of the following component (C) is supplied to the melt-kneading apparatus, and the component (A), the component (B) and the component ( The thermoplastic elastomer composition according to claim 1 or 2, which is obtained by dynamically heat-treating C) in the presence of a crosslinking agent.
Ingredient (C): Mineral oil softener   The thermoplastic elastomer composition according to any one of claims 1 to 3, wherein the melt-kneading apparatus is a twin screw extruder.   The rubber component (1) and the rubber component (2) are produced by using the two reaction tanks connected in series to produce either the rubber component (1) or the rubber component (2) in the first reaction tank. The heat according to any one of claims 1 to 4, which is a rubber component obtained by supplying a component produced in one reaction tank to a second reaction vessel and producing the other rubber component in a second reaction vessel. Plastic elastomer composition.   The thermoplastic elastomer composition according to any one of claims 1 to 5, wherein the crosslinking agent is an organic peroxide.