heißsiegelbare, flexible composite film and process for their production

摘要

The present invention relates to a heat-sealable flexible composite film comprising at least one heat-sealable film or heat-sealable layer based on a propylene copolymer with an ethylene content of 2.8 to 3.8% by weight and at least one carrier film or carrier layer based on a polyolefin, preferably based on polypropylene. The composite film can be thermoformed and is in the stretched state. The heat-sealable film(s) or heat-sealable layer(s) consist of 99.9-89.5% by weight, preferably 98.9-92.5% by weight, of the propylene copolymer, 0.05-7.5% by weight, preferably 1-5.5% by weight, of at least one high pressure polyethylene and 0.05-3% by weight, preferably 0.1-2% by weight, of at least one processing auxiliary and/or additive, preferably antiblocking agent, slip agent and/or lubricant, the torsion modulus of the propylene copolymer of the heat-sealable layer being below 35 N/mm2, preferably below 30 N/mm2, and the torsion modulus of the polymer of the carrier film or carrier layer being more than 7 N/mm2, preferably more than 20 N/mm2, higher than that of the random propylene copolymer of the heat-sealable layer.