Multi-layer film with enhanced lamination bond strength

Abstract

A laminated film structure that includes a primary web having a migratory additive in a first outer layer and a metallocene polyethylene in a second outer layer that can be laminated to a secondary web without treating the surface of the second outer layer with a primer or solvent. The primary web further includes a core substrate layer disposed between the two outer layers that can include a biaxially oriented polypropylene. The laminated film structures have improved bond strength between the primary web and the secondary web.

What is claimed is:  
     
         1 . A film structure comprising: 
 a primary web comprising: 
 (a) a first outer layer comprising a migratory additive;  
 (b) a second outer layer comprising a metallocene polyethylene and having an interior surface and an exterior surface; and  
 (c) a core substrate layer;  
 wherein said core substrate layer is disposed between said first outer layer and said second outer layer, and wherein said interior surface of said second outer layer is adjacent to said core substrate layer; and  
   a secondary web;    wherein said exterior surface of said outer layer of said primary web is laminated to said secondary web.    
     
     
         2 . The film structure of    claim 1   , wherein said migratory additive is selected from the group consisting of silicone oil, polydialkylsiloxanes, polydimethylsiloxane, polyalkylphenylsiloxanes, olefin-modified siloxane oils, polyether-modified silicone oils, olefin/polyether-modified silicone oils, epoxy-modified silicone oils, alcohol-modified silicone oils, antiblocking agents, antistatic agents, and slip agents.  
     
     
         3 . The film structure of    claim 1   , wherein said migratory additive is a silicone oil having a viscosity of from about 10,000 to about 30,000 centistokes.  
     
     
         4 . The film structure of    claim 1   , wherein said metallocene polyethylene is selected from the group consisting of ethylene homopolymers, copolymers of ethylene and at least one C 4 -C 20  alpha-olefin, wherein said alpha olefin is polymerized using a single-site metallocene catalyst and has a molecular weight distribution (Mw/Mn) below 5.5 and a Melt Index at 190 C of from 0.3 to 20 dg/min.  
     
     
         5 . The film structure of    claim 1   , wherein said first outer layer further comprises a polyolefin selected from the group consisting of homopolymers of polyethylene, polypropylene and polybutylene, and copolymers and terpolymers of polyethylene, polypropylene and polybutylene.  
     
     
         6 . The film structure of    claim 1   , wherein said primary web is not treated with a primer prior to lamination.  
     
     
         7 . The film structure of    claim 1   , wherein said metallocene polyethylene comprises an additive selected from the group consisting of 0.2 to 20 weight % high density polyethylene, 1 to 6,000 ppm spherical antiblock, 1 to 6,000 ppm random shape antiblock, antistatic agents and slip agents.  
     
     
         8 . The film structure of    claim 1   , wherein said metallocene polyethylene is selected from the group consisting of linear low density polyethylene, very low density polyethylene, ultra low density polyethylene, polyethylene plastomer and blends thereof.  
     
     
         9 . The film structure of    claim 1   , wherein said second outer layer further comprises a polyolefin selected from the group consisting of blends of 1% to 99% metallocene-based polyethylene and 99% to 1% Ziegler-Natta catalyzed ethylene homopolymer or copolymer and homopolymers and copolymers of polypropylene and polybutylene  
     
     
         10 . The film structure of    claim 1   , wherein said core substrate layer comprises a polyolefin selected from the group consisting of oriented polypropylene, high density polyethylene, and blends of polypropylene and polyethylene.