Foamed pvc films prodn - by luvitherm method calendering pvc mix contg blowing agent at two different temps

摘要

The films are produced by calendering a PVC mix. contg. pref. 0.1 - 3 wt.% blowing agent in a first stage at a temp. below the activation pt. of the blowing agent and in a second stage at a temp. above this pt. Pref. the temps. are 150 - 180 degrees C and 210 - 250 degrees C resp. The foamed films produced have good tear resistance and mechanical strength and are used for packaging/insulation and as pressure sensitive carriers.