Multi-layer film with core layer of syndiotactic polypropylene

Abstract

The present invention is directed to a biaxially oriented multi-layer film which comprises: (a) a core layer comprising a syndiotactic propylene homopolymer; and (b) at least one additional layer adjacent to the core layer comprising a polymer which is an ethylene or a propylene homopolymer, ethylene copolymer or terpolymer containing comonomers of propylene and/or butene-1. Optionally, there can be a skin layer applied to the exposed surface of the outer layer. The skin layer and/or the at least one additional layer is a polyolefin selected from the group consisting of isotactic polypropylene, polyethylene, ethylene-propylene random copolymer, ethylene-propylene block copolymer or ethylene-propylene-butene-1 terpolymer.

What is claimed is  
     
         1 . A biaxially oriented multi-layer film which comprises: 
 (a) a core layer comprising a syndiotactic propylene polymer; and    (b) at least one additional layer adjacent to the core layer comprising an ethylene or propylene homopolymer, an ethylene copolymer, a terpolymer containing propylene, ethylene, and butene-1 as comonomers, or a blend thereof.    
     
     
         2 . The biaxially oriented multi-layer film of    claim 1    which further comprises a coating and/or a skin layer adjacent the at least one additional layer, the skin layer comprising a polyolefin.  
     
     
         3 . The biaxially oriented multi-layer film of    claim 1    in which the skin layer is a polyolefin selected from the group consisting of isotactic polypropylene, ethylene-propylene random copolymer, ethylene-propylene block copolymer or ethylene-propylene-butene-1 terpolymer.  
     
     
         4 . The biaxially oriented multi-layer film of    claim 2    in which the coating is selected from the group consisting of a polyvinylidene chloride coating, a polyvinyl alcohol coating and an acrylic polymer coating.  
     
     
         5 . The biaxially oriented multi-layer film of    claim 1    in which the at least one additional layer further comprises silica particles.  
     
     
         6 . The biaxially oriented multi-layer film of    claim 1    further comprising an alicyclic hydrocarbon.  
     
     
         7 . A process for preparing an oriented multi-layer film which comprises the steps of: 
 (a) melt coextruding a film comprising: (i) a core layer comprising syndiotactic polypropylene, and (ii) at least one additional layer adjacent the core layer comprising an ethylene or propylene homopolymer, an ethylene copolymer, a terpolymer containing propylene, ethylene and butene-1 as comonomers, or a blend thereof; and    (b) orienting the coextruded combination in at least one direction.