GB621989A - Method of rendering woollen material resistant to shrinking - Google Patents

Abstract

Wool or wool goods are rendered resistant to shrinking on subsequent washing and laundering by treating them with an alkaline hypochlorite solution containing 1-6 per cent of available chlorine for a short time of 1 to 60 seconds, and immediately thereafter eliminating the hypochlorite from them. The treatment also has a bleaching effect on undyed materials. If dyes which are resistant to hypochlorite are used, the anti-shrink treatment may be effected on the dyed materials. A wetting agent such as a sodium salt of a sulphuric acid ester of a higher secondary alcohol, or a highly sulphonated fatty ester, may be added to the hypochlorite solution. Preferably, the treatment is carried out at a pH value of 7.5-10. The temperature may be 0-35 DEG C. Wool in the form of raw stock, tops, yarn, woven or knitted fabrics, may be treated. Cotton, rayon, or other fibres may be present. The process is preferably carried out in a continuous manner. The material may be passed through the hypochlorite solution in a padding machine from which it passes through squeeze rollers and then through a bath containing an antichlor. It is then rinsed in running water. In an example, a solution containing 3 per cent of available chlorine at pH 8.5 is prepared by dissolving 1 per cent of borax in water, adding commercial sodium hypochlorite solution, adding 0.8 per cent of a wetting agent and adjusting the pH with 2N sulphuric acid. Flannel shirt material is passed through the solution at 20 DEG C. and thence to squeeze rollers. It is then passed directly into a 1 per cent sodium bisulphite solution and then rinsed with running water. In another example, calcium hypochlorite is used. The material may be treated with a solution of a wetting agent before it passes into the hypochlorite solution.