Biaxially oriented and heat-set multilayer thermoplastic film for packaging
AssigneeCryovac, Inc.
InventorsEugenio Longo, Roberto Forloni, Gregorio Di Cesare
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Abstract
A multi-layer, thermoplastic film bi-axially oriented at a stretching ratio ≧ to about 3.0:1 in the machine direction and at a stretching ratio ≧ about 6.0:1 in the transverse direction, which film comprises a layer a) comprising at least 50 wt. % of a crystalline or partially crystalline co-polyamide characterized by a Tg≦100° C. and at least one outer heat-sealing layer b) comprising a polyolefin, said film being further characterized in that it has a % free shrink at 100° C.≦3 in each direction.
Claims15
A multi-layer, thermoplastic film, bi-axially oriented at a stretching ratio greater than or equal to 3.0:1 in the machine direction and at a stretching ratio greater than or equal to 6.0:1 in the transverse direction, which film comprises
- a) a layer comprising at least 50 wt.% of a crystalline or partially crystalline co-polyamide characterized by a Tg less than or equal to 100° C., and
- b) an outer heat-sealing layer comprising a polyolefin in, said film being further characterized in that it has a % free shrink at 100° C. less than or equal to 3 in each of the machine and transverse directions.
A process of manufacture of a film comprising:
- a) stretching an extruded tape comprising
- i) a layer comprising at least 50 wt.% of a crystalline or partially crystalline co-polyamide characterized by a Tg less than or equal to 100° C., and
- ii) at least one outer heat-sealing layer comprising a polyolefin in, in the machine direction with a stretching ratio of greater than or equal to 3.0:1 and in the transverse direction with a stretching ratio of greater than or equal to 6.0:1, either sequentially or simultaneously, at a suitably se-lected orientation temperature, to produce an oriented film, and then
- b) heat-setting the film;
- such that the heat set film is characterized by a % free shrink at 100° C. less than or equal to 3 in each of the machine and transverse directions.
Dependencies are inferred from the claim text.