Experimental Investigation on Cryogenic Impact Properties of Packaging Films, 1990 Polymers, Laminations & Coatings Conference Proceedings

Two Plackett-Burman fractional factorial experiments are conducted in order to determine the effect of cast film line process variables and resin variables on physical properties of extruded polypropylene film. Resins evaluated include a 3.5 MFR home-polymer, a 8.5 MFR homopolymer, a 3.5 MFR random copolymer, and an 8.5 MFR random copolymer. Machine independent variables are melt temperature, cast roll temperature, line speed, film gage, and roll tension.

The objective of this evaluation is to identify and quantify the important machine operating parameters as they affect cast film extrusion, attenuation, and quench characteristics, and to compare the process features of both homopolymers and copolymers, each at low and high melt flows.

Analysis of data from significance tables and effects graphs indicates that resin molecular weight influences physical and optical properties, but can be compensated for by controlling melt temperature. Roll tension is also an important factor in physical properties. Copolymer films are found to be less sensitive to machine operating parameter effects on tensile properties, but more sensitive to effects on optical and impact properties.