Process for manufacturing fibres or films from polyvinyl alcohol graft-copolymerized with acrylonitrile

摘要

1,126,975. Filaments and films of graft polymers. KURASHIKI RAYON K.K. 2 Feb., 1966 [21 April, 1965 (2)], No. 4560/66, Heading B5B. [Also in Division C3] Filaments and films are wet-spun or wet-cast from a dope comprising not less than 5% by wt. of a graft copolymer of polyvinyl alcohol (PVA) and acrylonitrile (AN), said copolymercontaining from 30-200% by weight AN based on the PVA, dissolved in an aqueous solution containing 25-80% of one or more of the salts ZnCl 2 , AlCl 3 , CaCl 2 , MgCl 2 , KCNS, NaCNS, NH 4 CNS and Ca(CNS) 2 . In examples filaments are wet spun (1) into 20% aqueous ZnCl 2 and dried, followed by polyethylene glycol sizing, stretching 6Î at 180‹ C., and heat shrinking by 20% at 140‹ C.; (2) into water and dried, followed by polypropylene glycol sizing, stretching 6 x in a molten metal bath at 180‹ C., and shrinking 20% in air at 150‹ C. In Example (3) a film is wet cast in water, longitudinally stretched 2 x while coagulated, dried, stretched 5 x longitudinally and then heat set at 180‹ C.