GB615305A - Improvements relating to the manufacture of textile fibres composed of casein or casein and cellulose - Google Patents

Abstract

Textile filaments or fibres are obtained by extruding a solution, particularly an aqueous solution, of casein or of casein and viscose into a coagulation bath which does not contain formaldehyde and treating the coagulated filaments in a succession of baths including or comprising a bath or baths consisting of urea dissolved in a solution of a neutral or acid salt of a mineral or organic acid and a urea-free saline bath or baths containing formaldehyde, the urea treatment preceding the formaldehyde treatment. The treated filaments are resistant to moisture and to hot soap solutions and dilute acids. The tensile strength may be increased by stretching the filaments and maintaining them under tension during their passage through at least the bath or baths containing formaldehyde or after leaving the bath and until they are cut to staple fibres. A large number of filaments may be gathered together and passed in ribbon form through the post-coagulation treatment baths. To obtain a higher resistance to hot acid liquors, one or more of the baths containing formaldehyde may be heated, e.g. to 70-75 DEG C. The saline solutions of urea may be concentrated as regards the salt and may have an astringent effect on the filaments. The salt may be sodium chloride, aluminium sulphate or other chloride, sulphate, formate, acetate, lactate, or nitrate. Instead of urea, there may be used a water-soluble urea salt or thiourea. In an example, casein is dissolved in caustic soda solution and the matured solution is spun into a coagulating bath containing sulphuric acid and sodium sulphate. The bundle of filaments obtained is passed in succession through an aqueous saline bath containing 200 grams per litre of sodium chloride, an aqueous saline bath containing 150 grams of sodium chloride, 200 grams of aluminium sulphate and 50 grams of alumina paste containing 10 per cent Al2O3, per litre, a similar bath containing in addition 100 grams of urea per litre and saturated as regards sodium chloride, and a similar bath containing 30-40 grams of formaldehyde per litre, but free from urea. The filaments are then cut to staple fibres and these are treated with a solution containing aluminium sulphate, sodium chloride and formaldehyde. The insolubilized fibres are washed and treated with an aqueous solution of sodium phosphate. Specifications 483,731, 483,807, 483,808, 483,809, 483,810, 510,131, 510,616, 510,656 and 511,160 are referred to.