Patent ID: 6203750
Filing Date: 2001-03-20
Classification: A22C,B29C,B29K,B29L,B32B,C08L

Abstract:
A process of making a biaxially-oriented multilayer film, comprising:(A) extruding a tubular multilayer tape comprising:(i) a first layer comprising a composition consisting essentially of a first polyamide and a second polyamide, wherein the first polyamide is a crystalline polyamide and wherein the second polyamide is a crystalline copolyamide, wherein the second polyamide has a different crystal structure than the first polyamide, and the first layer has a thickness of from about 2 to 12 percent, based on a total thickness of the tape;(ii) a second layer comprising a first polyolefin;(iii) a third layer which is an O.sub.2 -barrier layer comprising at least one member selected from the group consisting of ethylene/vinyl alcohol copolymer, polyvinylidene chloride, and polyalkylene carbonate, the third film layer having a thickness of less than about 15 percent, based on a total thickness of the tape;(iv) a fourth layer comprising a second polyolefin;(B) inflating the tape so that the tape is biaxially oriented by stretching in a transverse direction and machine direction, so that a tubular multilayer film is formed.