| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject composition having excellent heat-resistance, etc., of isobutylene copolymer and exhibiting excellent mechanical strength by including an isobutylene polymer, an organic rubber and a crosslinking agent for the organic rubber. SOLUTION: This composition contains (A) an isobutylene polymer having a number-average molecular weight of 3,000-50,000, containing a hydroxyl group or a hydrolyzable group bonded to silicon atom and holding on its molecular chain terminal at least one Si-containing group crosslinkable by forming a siloxane bond [preferably a hydrolyzable silyl group of the formula (R<1> and R<2> are each independently a 1-12C alkyl, a 6-20C aryl or the like; X groups are each independently hydroxyl group or a hydrolyzable group; (a) is 0, 1, 2 or 3; (b) is 0, 1 or 2; (a) and (b) are not 0 at the same time; (m) is 0 or an integer of 1-19)], (B) an organic rubber (e.g. natural rubber) and (C) a crosslinking agent for the component B. The composition is preferably further incorporated with (D) a silanol condensation catalyst. |
