THERMOPLASTIC ELASTOMER COMPOSITION
An object of the invention is to provide a thermoplastic elastomer composition, which includes a halogenated isoolefin/para-alkylstyrene copolymer rubber dispersed in a polyamide resin in order to improve the fatigue durability of a polyamide resin, while maintaining high flowability of the polyamide resin, even if a halogenated isoolefin/para-alkylstyrene copolymer rubber is finely dispersed and loaded to a high content. A thermoplastic elastomer composition comprising a continuous phase composed of a modified polyamide resin (A) and a dispersed phase composed of a halogenated isoolefin/para-alkylstyrene copolymer rubber (B) is provided. The modified polyamide resin (A) is a resin obtained by melt-kneading 100 parts by weight of a polyamide resin (C) with not less than 0.05 part by weight and less than 3 parts by weight a compound (D), such as a monofunctional epoxy compound, capable of binding to a terminal amino group of the polyamide resin at a temperature not lower than the melting point of the polyamide resin (C). The thermoplastic elastomer composition can be favorably used as an inner liner of a pneumatic tire.
1 . A thermoplastic elastomer composition comprising a continuous phase composed of a modified polyamide resin (A) and a dispersed phase composed of a halogenated isoolefin/para-alkylstyrene copolymer rubber (B), wherein the modified polyamide resin (A) is a resin obtained by melt-kneading 100 parts by weight of a polyamide resin (C) with not less than 0.05 part by weight and less than 3 parts by weight of a compound (D) capable of binding to a terminal amino group of the polyamide resin at a temperature of not lower than the melting point of the polyamide resin (C).
2 . The thermoplastic elastomer composition according to claim 1 , wherein the compound (D) capable of binding to a terminal amino group of the polyamide resin is a monofunctional epoxy compound.
3 . The thermoplastic elastomer composition according to claim 1 , wherein the polyamide resin (C) is at least one selected from the group consisting of nylon 11, nylon 12, nylon 6, nylon 66, nylon 6/66, nylon 6/12, nylon 6/10, nylon 4/6, nylon 6/66/12 and aromatic nylons.
4 . The thermoplastic elastomer composition according to claim 1 , wherein the halogenated isoolefin/para-alkylstyrene copolymer rubber (B) is a brominated isobutylene/para-methylstyrene copolymer rubber.
5 . The thermoplastic elastomer composition according to claim 1 , wherein the halogenated isoolefin/para-alkylstyrene copolymer rubber (B) is dynamically cross-linked.
6 . The thermoplastic elastomer composition according to claim 1 , wherein the amount of the halogenated isoolefin/para-alkylstyrene copolymer rubber (B) is 57 to 70 parts by weight based on 100 parts by weight of the total of the polyamide resin (C) and the halogenated isoolefin/para-alkylstyrene copolymer rubber (B).
7 . The thermoplastic elastomer composition according to claim 1 , further comprising a plasticizer (E) in an amount of 5 to 20 parts by weight based on 100 parts by weight of the total of the polyamide resin (C) and the plasticizer (E).
8 . The thermoplastic elastomer composition according to claim 7 , wherein the plasticizer (E) is butylbenzenesulfonamide.
9 . The thermoplastic elastomer composition according to claim 5 , wherein a cross-linking agent used for the dynamic cross-linking is zinc oxide.
10 . The thermoplastic elastomer composition according to claim 5 , wherein a cross-linking agent used for the dynamic cross-linking is a secondary amine.
11 . A pneumatic tire having an inner liner comprising the thermoplastic elastomer composition according to claim 1 .