FABRICATION METHOD OF PENTALAYER POLYOLEFIN STRETCH FILM

The matter of invention is the fabrication method of stretch pentalayer polyolefin film, in particular the plane film. the fabrication method of stretch pentalayer polyolefin film composed of following substrates: low density polyethylene, very low density polyethylene and metalocene linear polyethylene of low density, with the use of screw extruders feeding sheet die characteristic of that: - the copolymer of ethylene and n-hexene of mass flow rate (MFR) 1.0 to 6.0 g/10min; the best 4.0 g/min, was introduced to the first extruder feeding sheet die, used for the formation of first layer of thickness corresponding to 10-12% of total film thickness, - the mixture of copolymer of ethylene and n-hexene of MFR 1.0 to 6.0 g/10min; the best 4.0 g/min with copolymer of ethylene and n-hexene obtained in presence of metalocene catalyst, with MFR 1.0 to 6.0 g/10min; the best 4.0 g/min, in proportions 20-80% of the former; the best 50%, was introduced to the second extruder feeding sheet die, used for the formation of second layer of thickness corresponding to 28-32% of total film thickness, - the copolymer analogous to that introduced to first extruder, was introduced into third extruder feeding sheet die, used for the formation of third layer of thickness corresponding to 14-18% of total film thickness, - the mixture of copolymer of ethylene and n-hexene of MFR 1.0 to 6.0 g/10min, consisting 20-80%o contribution; the best 60% with polypropylene of MFR 2.0 to 6.0 g/10min, consisting 80-20% contribution; the best 40%, was introduced to the fourth extruder feeding sheet die, used for the formation of fourth layer of thickness corresponding to 28-32% of total film thickness, - the mixture of copolymer of ethylene and n-hexene of MFR 1.0 to 6.0 g/10min, consisting 40-95%) contribution; the best 80%, with copolymer of ethylene and n- hexene obtained in presence of metalocene catalyst, of MFR 1.0 to 6.0 g/10min, consisting 60-5% contribution; the best 20%, was introduced to the fifth extruder feeding sheet die. The temperature of sheet and separator was 260 °C. La présente invention concerne le procédé de fabrication de film étirable à cinq couches en polyoléfine, en particulier du film plan. Procédé de fabrication de film étirable à cinq couches en polyoléfine composé des substrats suivants : polyéthylène à basse densité, polyéthylène à très basse densité et polyéthylène linéaire métallocène à basse densité, reposant sur l'utilisation d'une filière de feuilles alimentant