Patent ID: 6194060
Filing Date: 2001-02-27
Classification: B32B,Y10S,Y10T

Abstract:
An opaque, oriented polymeric film structure comprising:(a) a core layer consisting essentially of a thermoplastic polymeric matrix material which has a first surface and a second surface, the core layer having a plurality of voids, substantially all or all of the voids being free from a void-initiating particle and at least some of the voids being interconnected with an adjacent void in the polymeric matrix material, the number of voids not containing a void-initiating particle being sufficient to impart a significant degree of opacity to the film structure; and(b) at least one outer or skin layer containing a thermoplastic polymeric material and an effective amount of a nucleating agent to suppress cavitation in said at least one outer or skin layer,wherein said film structure is made by a process comprising melting and extruding said thermoplastic polymeric matrix material into a sheet, cooling said sheet to form an amorphous polymeric matrix material in which crystallization is initiated but not completed, and orienting the cooled sheet in at least one direction.