HIGH MODULUS POLYVINYL ALCOHOL SYNTHETIC FIBERS AND PROCESS FOR PRODUCING THE SAME

摘要

1314000 Polyvinyl alcohol synthetic fibres UNITIKA Ltd 25 June 1971 [27 June 1970 (2)] 29987/71 Heading B5B Polyvinyl alcohol fibres are produced by spindrawing to give fibres of homogeneous crosssection which are then drawn at least twice at a high temperature. Preferably the draw ratios are 3À5 to 5 during spin-drawing and at least 3 during the first and at least 1À1 during the second hot drawing step. The preferred temperatures are above 160‹ C. for the first step and above 180‹ C. for the second and successive drawing steps. The moisture content during drawing steps after the first is preferably between 20 and 50%. The fibres exemplified are prepared by wet spinning an aqueous solution of polyvinyl alcohol into an alkaline coagulant bath.