GB1043393A - A method of treating keratinic fibres to improve their resistance to felting - Google Patents

Abstract

Keratinic fibres, e.g. wool, are felt-proofed by treating them with an aqueous solution of an alkali metal salt of N-dichloroisocyanuric acid having a pH of 6.5-9 continuously while maintaining them in motion in the solution. The treating solution may contain 20-100 g per litre of the alkali metal salt of N-dichloroisocyanuric acid and is preferably maintained at a temperature of 5-35 DEG C. The solution may also contain an anionic, nonionic or cationic surface active agent, e.g. a condensate of ethylene oxide with buryl alcohol. The fibres may subsequently be treated with acidifying, dechlorinating, rinsing and softening baths in any order, the liquid taken up by the fibres in passing through one bath being at least partly removed before passage through the next bath, e.g. by the use of wringers or suction apparatus. The acidifying bath may be an aqueous solution of a mineral or organic acid, e.g. hydrochloric acid, having a concentration such that the solution has a pH of 1.5-5. Suitable reagents for use in the dechlorinating bath are sodium bisulphite and sodium hydrosulphite and the softening agent may be a quaternary ammonium halide or an anionic or nonionic compound. The speed of passage of the fibres through the different baths may be between 0.5 and 15 metres per minute. The process may be carried out in a smoothing machine comprising a series of tanks in which the fibres circulate to become impregnated with the liquid contained therein, each tank containing a perforated drum partly immersed in the liquid and rotating about its axis against which the fibres are applied, complete and homogeneous impregnation of the fibres being ensured by drawing the treatment liquid into the perforated drum and discharging it at the upper part of the tank. The keratinic fibres may be treated in the form of combed or carded yarn, raw wool, skeins, woven or knitted fabrics or ready to wear articles.