ORIENTED POLYMERIC PRODUCTS

摘要

A continuous method of extruding an oriented plastics article of improved strength. A chemically reactive polymer (33a, 33b), monomer or other compound is included in the matrix material(s) and a (multilayer) parison (34) is extruded or melt-formed having built-in thermoplastic orientation caused by shear or caused by elongational flow. A reaction can be activated in the molten state thereof by additional heat resulting in a cross-linked structure or at least the mobility of the molecules being reduced, resulting in a longer relaxation time which makes the freezing of permanent orientation possible. The soft matrix can be stretched while still hot in the hoop and/or axial direction. Then, the product thus obtained is calibrated and cooled in an oriented state.