GB719319A - Improvements relating to the treatment in pickling baths of artificial filaments andfibres of proteins - Google Patents

Abstract

In the wet spinning of globular water-insoluble proteins, the filaments are passed, prior to hardening and in the form of a roving, through one or more salt baths containing acid, the temperature of the bath or baths increasing gradually in the direction of travel of the roving and the minimum temperature of each bath being above 18 DEG C. The baths may be caused to flow counter to the direction of the travel of the roving, the temperature at the inlet end then being greater than that at the outlet end for the liquid and the rate of flow being adjusted to give the required temperature gradient. Where a succession of baths is used, the respective temperature ranges in the baths may increase in successive baths. The baths may contain sodium chloride, sodium formate, sodium acetate, sodium lactate, magnesium sulphate, zinc sulphate, aluminium sulphate or aluminium chloride, or mixtures of these, and the acid may be sulphuric, hydrochloric, formic, acetic or lactic acid, or mixtures of these. Suitable compositions are specified in the examples. The filaments may be stretched during and/or after their passage through the baths, or they may be held under tension or not in these baths. After leaving the baths the roving may be held under tension and cut into fibres, or it may be cut while being stretched. The filaments may also be stretched in the spinning bath or after leaving it and before entering the acidified salt baths. In an example, a solution of commercial lactic casein is spun into an aqueous spinning bath comprising sodium sulphate and sulphuric acid, assembled into a roving and passed under tension through two baths in succession and flowing counter-current to the roving, each bath comprising an aqueous solution of sodium chloride, aluminium sulphate and sulphuric acid in varying proportions. The temperatures for these baths are, for the first bath, 33-38 DEG C. and 40-45 DEG C. at the entrance and exit of the roving respectively, and, for the second bath, 48-55 DEG C. and 55-80 DEG C., respectively. The roving is then cut and hardened in known manner, e.g. with formaldehyde. U.S.A. Specification 2,338,916 is referred to.