INCREMENTALLY STRETCHED FILMS WITH ENHANCED PROPERTIES AND METHODS FOR MAKING THE SAME

摘要

Methods of enhancing one or more physical properties of a thermoplastic film include incrementally stretching thermoplastic films in the machine direction and/or transverse direction. In one or more implementations, methods of incrementally stretching thermoplastic films include reducing the gauge of the films without reducing the films' machine-direction tear resistance. The methods can involve cold stretching the films and imparting rib patterns into the film. The linear ribs can have alternating thick and thin gauges. Incrementally stretched thermoplastic films can have a machine-direction tear resistance that is approximately equal to or greater than the machine-direction tear resistance of the film prior to stretching.

主权项

1. A method of enhancing one or more physical properties of a thermoplastic film, comprising:
providing a blown film of thermoplastic material with a first machine-direction tear resistance and a first gauge by weight; and cold transverse-direction ring rolling the film; wherein:
the machine-direction and transverse-direction ring rolled film has a second machine-direction tear resistance that is equal to or greater than the first machine-direction tear resistance, andthe machine-direction and transverse-direction ring rolled film has a second gauge by weight that is less than about 0.95 times the first gauge by weight.