PRODUCTION OF DRAWN HIGH-MOLECULAR WEIGHT POLYOLEFIN

摘要

PURPOSE:To enable the drawing of a polyolefin over a long period while suppressing the breakage in drawing and to obtain the subject drawn polymer having high draw ratio by extruding a high-molecular weight polyolefin (composition) kneaded in molten state and supplying the obtained drawing precursor to a drawing apparatus while keeping the precursor at a specific temperature. CONSTITUTION:An ultra-high molecular weight polyolefin having an intrinsic viscosity [<=] of >=5dL/g or a composition consisting of a mixture of the ultra- high molecular weight polyolefin powder and paraffin wax is melted and kneaded with a twin screw extruder having the same screw-revolution directions and continuously melt-spun from a spinning die attached to the extruder. The obtained undrawn fiber of the drawing precursor is supplied at <40 deg.C to a drawing apparatus in air or in an inert gas atmosphere and subjected to multi- stage drawing at a draw ratio of 5-80 using four godet rolls to enable the drawing of the polyolefin over a long period while suppressing the troubles such as breakage in drawing and obtain the objective drawn polyolefin having high molecular weight.