GB596536A - Improvements in or relating to the production of insolubilised protein artificial filamentary products - Google Patents

Abstract

Artificial filamentary products obtained from the spinning of vegetable seed globulins such as peanut proteins, or casein, in aqueous alkaline or other suitable media into acidified saline coagulating solutions are rendered insoluble by treatment in a solution of formaldehyde in substantially saturated sodium chloride solution at a pH between 4 and 6 at a temperature insufficient to soften the filaments and subsequently in an acidified brine formaldehyde solution containing not less than 30 parts of sodium chloride per 100 parts of water by weight and sufficient hydrochloric or sulphuric acid to bring the pH below 1. The unhardened filaments are rinsed free from the coagulating solution with saturated brine prior to the formaldehyde treatment. The formaldehydebrine solution should be in large excess and the time of treatment should vary with the temperature. At 40 DEG C. a few minutes should be sufficient, at room temperature a few hours. The concentration of formaldehyde in the solution of pH 4 to 6 may be of the order of 1 to 3 per cent. The second formaldehyde brine treatment may be carried out between 35 DEG and 50 DEG C. for several hours. It is not necessary to maintain the coagulated filaments under tension in either bath, since if contraction does occur products of good handle, lustre and physical properties are obtained. In an example, a 24 per cent solution of peanut globulin in dilute caustic soda is extruded into a coagulating bath consisting of 2 per cent sulphuric acid, 28 per cent sodium sulphate and 70 per cent water. The filaments are collected at several times the speed of extrusion. After being cut into fibres, the material is immersed in a large volume of solution made by dissolving sufficient formaldehyde in strong sodium chloride solution to give a formaldehyde concentration of 1 1/2 per cent, and then adding solid sodium chloride to saturate it. The pH is adjusted to 5 by the addition of either hydrochloric acid or sodium hydroxide, whichever is required. The time of immersion is two hours and the temperature 20 DEG C. It is removed, drained and immersed in a second formaldehyde-saturated brine bath containing 1 1/2 per cent of formaldehyde and 2 1/2 per cent of sulphuric acid. This bath is at 38 DEG C. and the time of treatment is 18 hours. After washing and centrifuging, the fibres are soaked in sodium cetyl sulphate and their residual acidity removed in a large excess of 0.5 per cent sodium carbonate solution. After a further washing and centrifuging, the fibres are dried at 40 DEG C. in a current of air. Specifications 513,910 and 543,586 are referred to.