| 摘要 |
The invention relates to a method of continuously manufacturing profiled elements from crystal-clear polyvinyl chloride. According to the invention, the starting materials of the formulation are mixed, compounded by supplying heat and by friction in an extruder to form a homogeneous melt and subsequently the melt stream is introduced into a mould. According to the invention, on entry into the moulding area, the melt stream is subjected to an increased melt pressure. The consequence of this increased melt pressure is the occurrence of melt fracture in the moulding contact areas with the melt stream. The melt fracture thus produced is only eliminated incompletely on passing through a short, parallel die land at the end of the moulding area. As a result, a profiled surface having approximately the same roughness height in the longitudinal and transverse directions is achieved. |
