GB376295A - Improvements in and relating to the treatment of textile filaments and fabrics and other manufactured coherent structures formed from or containing cellulosic material - Google Patents

Abstract

Cellulose filaments, yarns and fabrics whether artificially produced or not, and other manufactured or coherent cellulosic structures are rendered water-repellant or are improved as regards their feel and suppleness by partial esterification with higher fatty acid radicles by means of acid chlorides in the presence of pyridine as in the process of Specification 343,104. The conditions to be observed in the present process are (1) a diluent other than pyridine should not be used, (2) the acid chloride should be in relatively high concentration in the pyridine, for example, 1 part of acid chloride to 7,5-15 parts of pyridine, (3) the esterification should be carried out in the absence of water as by the use of a closed vessel for the esterification and by pre-drying the materials, (4) for imparting water-repellent properties, the increase in weight of the materials should not exceed 10 per cent, preferably it should be 1-2 per cent, (5) to improve the feel and suppleness, the increase in weight should not exceed 30 per cent, preferably it should be 5-10 per cent, and generally the higher fatty acid radicles should be introduced in an amount exceeding twice the amount in the natural fibre, (8) dressings, finishes, &c. should be removed prior to esterification, (9) the period of esterification should not exceed 1-2 hours at 90 DEG C., conveniently it should be about half an hour, (10) any acid set free during the esterification is neutralized by the presence of finely-divided alkali metal carbonate in the reaction mixture, and (11) piece goods during the esterification should be maintained in motion as by passage through the liquid by winding backwards and forwards between rollers. Thus, in carrying out the esterification of piece goods, a closed chamber provided with a hot-water jacket and with a pair of winding rollers arranged to be alternately driven, is conveniently employed; the fabric if not previously dried, is drawn backwards and forwards while warm air is passed through the chamber until all moisture is removed; the fabric is then soaked in pyridine and at the same time finely-divided alkali metal carbonate incorporated therein, the chamber being heated to 85-90 DEG C.; stearic acid chloride is then run in, the fabric being still kept in motion; after about half an hour the esterification liquid is removed, and a solution of soda added to saponify any remaining acid chloride, and afterwards the material is washed with warm water or with soap solution, and alcohol, benzene, or petrol. To protect the parts of apparatus from corrosion, the vessel itself is enamelled, and the drums are of porcelain and of large diameter so that their bearings are not immersed in the liquid; and the latter may be further protected by stuffing-boxes, and they may be water-cooled to condense escaping pyridine vapour. The drums are allowed axial movement to prevent any running-off of the fabric. Reference has been directed by the Comptroller to Specification 343,104.