Method for preparing thermoplastic elastomer composition
View Patent ↗Provided is 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. 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 composition can be used as an inner liner of a pneumatic tire.
1. A method for preparing 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), which comprises
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) to obtain a modified polyamide (A); and
melt-kneading the modified polyamide (A) and a halogenated isoolefin/para-alkylstyrene copolymer rubber (B)
wherein the compound (D) capable of binding to a terminal amino group of the polyamide resin is a monofunctional epoxy compound.
2. The method according to claim 1 , wherein the polyamide resin (C) is at least one member 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.
3. The method according to claim 1 , wherein the halogenated isoolefin/para-alkyl styrene copolymer rubber (B) is a brominated isobutylene/para-methylstyrene copolymer rubber.
4. The method according to claim 1 , wherein the halogenated isoolefin/para-alkylstyrene copolymer rubber (B) is dynamically cross-linked.
5. The method 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).
6. The method 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).
7. The method according to claim 6 , wherein the plasticizer (E) is butylbenzenesulfonamide.
8. The method according to claim 4 , wherein a cross-linking agent used for the dynamic cross-linking is zinc oxide.
9. The method according to claim 4 , wherein a cross-linking agent used for the dynamic cross-linking is a secondary amine.
10. A pneumatic tire having an inner liner comprising the thermoplastic elastomer composition obtained by the method according to claim 1 .