GB369139A - Manufacture of artificial materials from fibroin solutions - Google Patents

Abstract

Aqueous neutral or feebly alkaline fibroin solutions are spun into a concentrated salt solution and the coagulated product stretched. The coagulation bath may comprise a concentrated solution of an inorganic salt, or of an organic salt, or of a mixture of these, if desired with an addition of an inorganic or organic acid, or both. In examples, (1) natural silk waste is dissolved in sodium thiocyanate solution, which is dialysed, concentrated, and spun with stretching into a 40 per cent solution of ammonium sulphate; (2) a fibroin solution obtained as in (1) is spun into a bath containing 50-60 per cent of ammonium formate and 3 per cent of formic acid, and the thread stretched; (3) a fibroin solution prepared as in Specification 355,161 is spun into a bath of 42 per cent of ammonium sulphate and 4 per cent of sulphuric acid, and the thread stretched to 4,3 times its length; (4) a solution of fibroin in ammoniacal copper oxide, from which the ammonia has been removed, is spun into a bath containing 42 per cent of ammonium sulphate and 4 per cent of acetic acid, and the thread stretched to six times its length; (5) a fibroin solution as in (4) is spun into a bath containing 39 per cent of ammonium sulphate and 2,4 per cent of sulphuric acid, and the thread stretched to 4,5 times its length.