Patent ID: 6040061
Filing Date: 2000-03-21
Classification: B32B,Y10T

Abstract:
A tear resistant film comprising a total of at least three stiff and ductile layers situated one on the other in a parallel array, the layers occurring essentially randomly in the array wherein (a) at least one layer is a stiff polyester or copolyester that has a tensile modulus greater than 200 kpsi, (b) at least one other layer is a ductile sebacic acid based copolyester that (i) comprises at least 1 mole equivalent of sebacic acid, including ester derivatives thereof, based on 100 mole equivalents of acid components, including ester derivatives thereof, in the copolyester, (ii) has a tensile modulus less than 200 kpsi, (iii) has a tensile elongation greater than 50%, and (iv) provides from about 1 weight percent to 50 weight percent of the tear resistant film, and (c) the tear resistant film demonstrates a Graves area in one direction of the film which exceeds the Graves area, in the same direction, of a single layer film having a thickness substantially equal to the thickness of the tear resistant film, the single layer film including only the stiff polyester or copolyester of the tear resistant film.