PURPOSE: To provide the titled composition having high green strength and creasing resistance, and excellent processability, by compounding a butyl rubber with an ethylene-α-olefin-nonconjugated diene copolymer rubber having specific green strength and cyclohexane-insoluble content.
CONSTITUTION: The objective composition can be produced by compounding (A) a copolymer rubber composed of ethylene, an α-olefin (a 3W12C α-olefin, preferably propylene) and a nonconjugated diene (preferably 5-ethylidene-2- norbornene and/or dicyclopentadiene), having a green strength of 10W40kgf/cm2, preferably 10W30kgf/cm2 and a cyclohexane-insoluble content of ≤15(wt)%, preferably ≤12% at 30°C in the state of raw rubber, and having an ethylene content of 60W85mol% (ethylene/α-olefin) and bonded amount of diene unit of 2W40 in terms of iodine value, with (B) a butyl rubber at a weight ratio of (5W40)/(95W60), preferably (5W30)/(95W70).
NISHIHATA SHUJI
KAWATOKO MITSUHIRO
MATSUMOTO HIRONORI
