PREPARATION OF CONTROLLED ATMOSPHERE PACKAGING FILMS BY MELT BLENDING POLYMER/FILLER MIXTURE HAVING PREDETERMINED MOISTURE CONTENT AND STRETCHING THE RESULTANT CAST FILM IN ONE DIMENSION BY A FACTOR OF AT LEAST TWO

摘要

ANTOON CASE No. 2UNIAXIALlY ORIENTED FILLED FILMSFOR CONTROLLED ATMOSPHERE PACKAGINGAbstract of the DisclosureA uniaxially oriented, polyolefin film is prepared bymelt blending a mixture of a polyolefin, an inert filler, anda processing aid such as calcium stearate, maintaining themoisture level in the melt blend below 700 ppm, casting afilm, and uniaxially stretching the film at least about 2times its original casting dimension in one direction untilthe film has a sufficient number of elongated, microporousvoids in order to create a CO2 and 02 permeance in therange of 5,000 to 10,000,000 cc/1002-atm-day, the a filmbeing used as a panel in a side of a controlled atmospherepackaging container that is otherwise substantially gasimpermeable.