A vacuum melting device, in which the material to be treated with the aid of an electrical gas discharge in front of gear, with simultaneous supply of a controllable amount of gas into the discharge zone, can be heated to melting heat, and a method for the operation of this device

摘要

An extrudable composition comprises 100 parts by weight of an isoolefin-conjugated diene copolymer and 1 to 20 parts by weight of an ethylene polymer which has a density of at least 0.94 at 25 DEG C., a crystallinity of at least 80% at 25 DEG C., and a softening point of at least 250 DEG F. Crystallinity is determined by nuclear magnetic resonance. The ethylene polymer may be made using a "Ziegler" type catalyst or a supported metal oxide-type catalyst, and may be polyethylene or a copolymer of ethylene with propylene, 1-butene, 2-butene, or 1-octene. The isoolefin may be isobutylene, iso-pentene, or isooctene, and the diene butadiene, 2-methyl-1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, or 1,3-hexadiene. The composition may be made by blending in a Banbury mixer, or on a roll mill at a temperature up to 300 DEG F.