GB525577A - Improvements in and relating to the preduction of textile threads - Google Patents

Abstract

525,577. Artificial filaments &c. COURTAULDS, Ltd., and WILSON, D. L. Feb. 23, 1939, No. 6052. [Class 2 (ii)] Artificial filaments, yarns, films, or the like obtained from solutions of casein, soya bean protein, arachis nut protein, or similar protein are subjected to the action of a hardening medium containing formaldehyde in such manner that only part of the desired hardening takes place, and the final hardening is effected after drying the partially hardened filaments, by subjecting them to a heat treatment. The partial hardening may be effected in stages. After the partial hardening has been carried out, sufficient of the hardening agent is left in or on the filaments to enable the further hardening to take place during the subsequent heating. In addition to the formaldehyde, the hardening medium may contain other aldehydes, synthetic tanning agents, salts of aluminium or chromium, organic or inorganic salts of alkali metals, and substances having an acid or alkaline reaction added to adjust the pH value. The heating of the dried products may take place at 90-135‹C. and if desired in an inert atmosphere or under reduced pressure. Between the partial hardening and the drying steps, the products may be washed with water or a solution of formaldehyde and a salt. If desired, thorough washing may be followed by re-impregnation with formaldehyde. The treated products may have a reduced affinity for wool dyestuffs. In an example, an aqueous solution of casein in caustic soda is spun into sulphuric acid and sodium sulphate. The threads produced are drawn through solutions of sodium chloride and then through solutions containing sodium chloride, sodium sulphate, and aluminium sulphate. It is then cut to staple fibre. The fibres are then further hardened by treatment with a solution of sodium acetate, and formaldehyde. The partially hardened fibres are rinsed and dried and then heated at 130-135‹C. for a few hours. In other examples the fibres are partially hardened with a solution of chromium sulphate or basic aluminium nitrate and formaldehyde. In another example, the fibres are washed with water and then with acetone before the drying and heating step. In another example, the casein fibres, preliminarily hardened with aluminium sulphate solution are further hardened with a solution of basic aluminium sulphate and formaldehyde, then washed, treated with sodium phosphate and formaldehyde, dried, and then heated at 130‹C.