GB440449A - Improvements in the manufacture of artificial silk or artificial spinning threads - Google Patents

Abstract

In the manufacture of artificial silk or artificial spinning threads of wool-like character from alkaline cellulose solutions, particularly viscose, by the wet spinning process, wherein an albuminous substance of vegetable or animal origin is added, this substance is added to the solution shortly before spinning in order to avoid material decomposition of the albuminous substance. The substance may, for example, be added immediately before or during the de-aeration of the spinning solution, or may be intermixed continuously as the spinning solution passes from the spinning tank to the spinning machine, mixing devices of known type being employed to ensure thorough mixing without aeration. Suitable substances are albumin and casein, or other albuminous substance of sufficiently high molecular weight to be insoluble in the spinning solution. Substances which aid the albuminous substance to produce in the cellulose fibres the capacity for being dyed with acid wool-dyestuffs, e.g. the sulphate of zinc, magnesium, or aluminium may be added to the spinning bath. The spun fibres may be after treated with formaldehyde. In an example a viscose solution containing 7,5 per cent of cellulose and 6--7 per cent of alkali is mixed with a 5 per cent aqueous albumin solution shortly before spinning and while avoiding access of air so that the solution contains about 10 parts of albumin per 100 parts of cellulose. The mixture is then spun, e.g. into a bath containing 13 per cent H2SO4 and 30 per cent Na2SO4. Metal salts, e.g. 0,5 per cent of zinc sulphate may be added to the spinning bath especially when spinning fine threads.