Transparent polyolefin foil prodn. - using calender rollers, the last pair of which is maintained below crystalline m.pt. and accelerated w.r.t. preceding rollers

摘要

Transparent polyolefin foils are produced by passage through calendar rollers, such that at the nip of the first calender roller pair the temp. of the foils is maintained above that of the crystalline m. pt. and the surface of at least the last pair of calender rollers is maintained below the m. pt., whilst the preceding pairs of rollers are maintained above the temp. Rollers are maintained at below the temp. are given an acceleration from 10-100% and the conditions at the nip are selected such that the bead forming at the inlet to the nip is imparted a rotary motion. The process is for mfr. of transparent polyolefin foils or plates having a turbidity index 10% measured at 200 mu in accordance with DIN 53490.