GB567904A - Improvements in or relating to the production and treatment of artificial textile fibres - Google Patents

Abstract

The resistance of artificial fibres, filaments, threads and the like, obtained from solutions of lactic casein, to attack by hot liquids, is improved by subjecting them first to a preliminary hardening treatment and then to a treatment with an aqueous solution containing formaldehyde, at least 30 per cent calcium chloride and 3 to 7 per cent of hydrochloric acid. The preliminary hardening treatment may be effected in a solution containing formaldehyde and sodium sulphate. The solution is preferably neutral, its pH value being adjusted substantially to 7 by the addition of an alkali, e.g. sodium hydroxide or sodium carbonate. In the examples, a solution of milk casein is extruded into a coagulating bath containing sulphuric acid and sodium sulphate. The resultant threads are passed through an aqueous bath containing sodium sulphate and aluminium sulphate or through aqueous baths of sodium chloride and aluminium sulphate with sodium chloride, and preliminarily hardened in a bath or baths of a solution of sodium sulphate containing formaldehyde, the pH value of which may be adjusted to 7 by addition of sodium hydroxide. They are then washed, dried, immersed in a saturated solution of calcium chloride containing hydrochloric acid and formaldehyde, and finally washed and dried. Specifications 483,810, 502,710, 511,160, 512,640, 513,910 and 533,952 are referred to.