Olefin polymer films

摘要

A film or sheet material 95-60 wt. % heteroplastic olefin polymer compsn. (I) and 5-40 wt. % of an ethylene alpha-olefin copolymer (II) of density 0.890-0.940 g/cc in which the alpha-olefin is of formula CH2=CHR (R = 1-8C alkyl). The heteroplastic olefin polymer compsn. (I) comprises 10-50 wt. % propylene polymer (III), 5-20 wt. % semi-crystalline linear copolymer fraction (IV) and 40-80 wt. % xylene-soluble copolymer fraction (V). (III) has an isotactic index greater than 80 and is propylene homopolymer or a copolymer contg. over 80 wt. % propylene with ethylene and/or a 4-10C alpha-olefin. (IV) has a crystallinity of 20-60 % and is insoluble in xylene at room temp. (IV) is a copolymer of ethylene and propylene contg. over 55 wt. % ethylene, or a copolymer of ethylene, propylene and 1-10 wt. % 4-10C alpha-olefin in which the combined content of ethylene and 4-10C alpha-olefin is over 55 wt. %, as a copolymer of ethylene and a 4-10C alpha olefin contg. over 55 wt. % 4-10C alpha-olefin. (V) has a intrinsic viscosity of 1.5-4.0 dl/g and is a copolymer of ethylene and propylene contg. 20-40 wt. % ethylene at a copolymer of ethylene, propylene and 1-10 wt. % 4-10C alpha-olefin in which the combined content of ethylene and 4-10C alpha-olefin is 20-40 wt. % or a copolymer of ethylene, 4-10C alpha-olefin and opt. 0.5-10 wt. %, diene, in which the 4-10C alpha-olefin content is 20-40 wt. %. The wt. ratio of (IV):(V) is less than 0.4:1. (I) is prepd. by polymerisation in at least 2 stages.