Biaxially stretching thermoplastics sheet - edge beading for transverse stretching is formed after sheet is stretched longitudinally

摘要

An appts. for longitudinally and transversely stretching thermoplastics sheet utilises transverse stretching clamps which grip edge beadings of the sheet. These beadings are produced in the initially flat sheet by a separate beading device incorporated upstream of the transverse stretching section. Pref., the longitudinal stretching is effected by smooth rolls then the sheet passes through the beading device then it is transversely stretched. A heater may be used just upstream of the beading device.