Polyolefin compositions for heat-sealable films having controlled peel strength

摘要

Polyolefin compositions comprising: (A) 20 - 50 wt.% low density polyethylene (LDPE), high density polyethylene (HDPE) or ethylene-vinyl acetate copolymer (EVA) having melt flow rate (MFR) above 0.3 g/10 min.; (B) 50 - 80 wt.% random copolymer (B1) of propylene with 7 - 40 wt.% 4 - 8C alpha-olefin and optionally 0.5 - 6 wt.% ethylene, and optionally a random copolymer (B2) of propylene with up to 10 wt.% ethylene and/or 1 - 6 wt.% 4 - 8C alpha-olefin and/or a propylene homopolymer, (B1) comprising at least 20 wt.% of (B); and (C) 0 - 20 wt.% elastomeric or elastomeric thermoplastic olefin polymer. Also claimed are (1) Polyolefin compositions comprising: (A) as above; (B) 30 - 79 wt.% random copolymer (B2) of propylene with up to 10 wt.% ethylene and optionally 1 - 6 wt.% 4 - 8C alpha-olefin, and optionally a propylene homopolymer, (B2) comprising at least 20 wt.% of (B); and (C) 1 - 30 wt.% elastomeric or elastomeric thermoplastic olefin polymer, provided that, when it is a copolymer of propylene with a 4 - 8C alpha-olefin and optionally 0.5 - 6 wt.% ethylene, it contains more than 40 wt.% 4 - 8C alpha-olefin. (2) Multilayer film for packaging comprising sealing layer(s) composed of or comprising a polyolefin composition as above and support layer(s) composed of or comprising a polymeric material.