Abstract: A crosslinked, unsaturated elastomeric polymer of a C.sub.4 to C.sub.7 isomonoolefin and a C.sub.4 to C.sub.14 conjugated multiolefin is produced by curing the corresponding uncrosslinked polymer having a low level of chemically bound halogen with a curing agent which reacts only with the halogen (e.g., zinc oxide) in combination with a bifunctional dienophile (e.g., a bismaleimide). The uncrosslinked elastomeric polymer is particularly suitable for use in the pharmaceutical industry, for example, for container closures. Shaped rubbery products comprising the crosslinked copolymer are also provided.

Abstract: A partially crosslinked, unsaturated elastomeric polymer of a C.sub.4 to C.sub.7 isomonoolefin and a C.sub.4 to C.sub.14 conjugated multiolefin is provided which has a low crosslink density. The partially crosslinked polymer is produced by curing an uncrosslinked unsaturated polymer having a low level of chemically bound halogen with a curing agent which reacts only with the halogen. Processes for preparing these partially crosslinked unsaturated polymers are also provided.

Abstract: A partially crosslinked, unsaturated elastomeric polymer of a C.sub.4 to C.sub.7 isomonoolefin and a C.sub.4 to C.sub.14 conjugated multiolefin is provided which has a low crosslink density. The partially crosslinked polymer is produced by curing an uncrosslinked unsaturated polymer having a low level of chemically bound halogen with a curing agent which reacts only with the halogen. Processes for preparing these partially crosslinked unsaturated polymers are also provided.

Abstract: A stabilized halogenated butyl rubber composition comprises halogenated butyl rubber, an alkali metal or alkaline earth metal carboxylate, an ether and an oxide or hydroxide of a Group IIA metal as exemplified by halogenated butyl rubber containing both bromine and chlorine stabilized with a composition comprising calcium stearate, polyethoxylated adducts of sorbitol esterified with from 1 to 6 moles of oleic acid and mixtures thereof, and calcium hydroxide.Halogenated butyl rubbers stabilized in the manner disclosed exhibit improved resistance to discoloration upon high temperature exposure, such as during the drying of polymers in the course of manufacture.

Abstract: A stabilized halobutyl rubber composition comprises (1) a halobutyl rubber e.g. chlorobutyl, (2) an alkali metal carboxylate or an alkaline earth metal carboxylate e.g. calcium stearate and (3) an ether, e.g. a polyether.With this stabilization system during the drying process in the halobutyl plant hydrogen halide evolution is strongly delayed and even if some hydrogen halide is evolved, usually no cross-linking occurs.