GB762401A - Improvements in or relating to a method for insolubilising artificial filaments, threads, fibres and the like obtained by the spinning of solutions of proteins - Google Patents

Abstract

<PICT:0762401/IV(a)/1> A continuous travelling tow of protein filaments, obtained by spinning aqueous alkaline solutions of vegetable seed globulins and (or) phospho-proteins into a sulphuric acid-sodium sulphate bath, is insolubilized under substantially tension-free conditions by impregnation first with a concentrated solution at a pH up to 7 of at least one salt which is a non-hardening agent for protein, the solution being retained in contact with the filaments at a temperature between 40-98 DEG C. until a sample on washing and drying gives discrete filaments, and then at a raised temperature (70-98 DEG C., preferably 90-98 DEG C.) with a strongly acidified aqueous formaldehyde solution containing at least 340 gms. sodium sulphate and 200 gms. sulphuric acid per litre, and preferably also containing sodium chloride. The total treatment time with the two insolubilizing solutions is 1-30 minutes. The salt, which is a non-hardening agent, preferably has a concentration of more than 10 per cent, and may be an alkali metal salt of hydro-chloric, sulphuric or phosphoric acid or ammonium or magnesium sulphate; this solution may additionally contain a colour-improving agent such as sodium chlorite, sodium formaldehyde sulphoxylate or sodium dithionite. As shown, a tow 3 is obtained by spinning a globulin solution into the sodium sulphate-sulphuric acid bath 2. The filaments are stretched by godets 4, 5 and by godets 6, 7 immersed in another sodium sulphate sulphuric acid bath 8, and then pass to godets 10, 11 which are immersed in the slightly alkaline bath 12 (pH8-9) containing sodium sulphate and sodium chloride at 25 DEG C. The emerging filaments have liquid adhering to them of pH3-6 and pass to a ring trough 13 (which slowly rotates) immersed in a bath of the same salt concentration, but at pH 4 and a temperature of 70 DEG C., in which they stay for about 10 minutes for the first stage of the insolubilization. The filaments then pass to a constant feed cone 20 and tube 24 for the second and final stage of the insolubilization with a solution of sodium sulphate, sodium chloride, sulphuric acid and formaldehyde at a temperature of 85-90 DEG C., the second stage being completed in about 7 minutes. Specifications 513,910, 533,952, 597,497, 605,830, 623,460, 642,359 and 708,057 are referred to.