Polymeric film and film structures having improved oxygen transmission, forming, and puncture resistance

摘要

Disclosed herein is a breathable polymeric film involving at least one polymeric layer of 100% neutralized ionomer containing sufficient aliphatic, mono-functional organic acid salt to essentially triple the oxygen transmission value (OTV) and/or at least one polymeric layer of metallocene polyethylene (mPE) optional blended with low density polyethylene and preferably in combination with one or more outer layers of highly neutralized ionomer (e.g., Surlyn(r)). Such polymeric film and polymeric film structure has sufficient oxygen permeability, water vapor transmission, formability, and structural strength to be useful in wrapping food products requiring breathable films such as case ready meat, fish, sausage, fresh produce, and the like. Particularly disclosed is a multilayer polymer film, wherein at least one layer of said multilayer polymeric film consists essentially of (1) one or more E/X/Y copolymers or ionomers of E/X/Y copolymers and optionally an antioxidant, or (2) a blend of (a) one or more aliphatic, mono-functional organic acids having fewer than 36 carbon atoms or salts thereof and (b) one or more E/X/Y copolymers or ionomers of E/X/Y copolymers and optionally (c) an antioxidant; where E is derived from ethylene, X is derived from C3 to C8 a,b-ethylenically unsaturated carboxylic acids, and Y is derived from a softening comonomer; wherein X is about 3 to 30 wt.% of said E/X/Y copolymer, and Y is 0 to about 30 wt. % of said E/X/Y copolymer; and from 15% to 100% of all acid moieties of (a) and of (b) are nominally neutralized to the corresponding salts of magnesium, sodium, zinc or mixtures thereof.