Opaque polymeric films and processes for making the same

The present invention relates to opaque, oriented polymeric films and to processes for making such films. More particularly, the invention relates to opaque, oriented polymeric films comprising a cavitated or voided core layer and at least one smooth outer or skin layer, and to processes for making the same. An opaque, oriented polymeric film structure comprising: a core layer comprising a thermoplastic polymeric matrix material wherein the core layer has a first side and a second side, 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, wherein the core layer comprises the interior of the film structure; and a first skin layer comprising a thermoplastic polymeric material and an effective amount of a high-melting incompatible additive to suppress cavitation in said first skin layer, wherein the first skin layer is exterior to the first side of the core layer. In another embodiment, the film structure comprises a second skin layer comprising a thermoplastic polymeric material and an effective amount of a high-melting incompatible additive to suppress cavitation in said second skin layer, wherein the second skin layer is exterior to the second side of the core layer.