Thick marbled thermoplastics sheets mfr. by calendering - comprises uniformly compounding and calibrating the moulding cpd. through a roller nip

摘要

The process comprises feeding a moulding cpd. between 2 feed-in rollers, into a pressure chamber defined by closely adjacent calender rollers, preventing a relaxation (detensioning) or pressure redn. of the material as it issues from the feed roller nip. At the same time, the cpd. is calibrated as it leaves the pressure chamber. The multi-coloured material is subjected to a uniform compounding action along a mirror-symmetrical path from the feed-in roller nip through the pressure chamber until it issues through the calibrating nip. A marbled or veined effect is achieved which extends throughout the entire thickness of the sheet.