Patent GB-550541-A (GB)
Title: Improvements in treatment of animal fibres to reduce their tendency to felt
IPC: D06M15/423
Filed: 1941-07-22
Abstract: 550,541. Anti-shrink treatments. TOOTAL BROADHURST LEE CO., Ltd.. MARSH. J. T., WOOD. F. C., and COWLEY, J. F. July 22, 1941, Nos. 9230 and 9231. [Classes 2 (iii) and 15 (ii)] To avoid undue chemical attack, on wool or other animal fibre during anti-felting treatments, the material is first impregnated with a resist, which may subsequently be removed. The resists may include "potential" resists such as low molecular weight condensation products of urea, thiourea, cyanamide, melamine, ammonium cyanate, dicyanamide, casein, or phenol with formaldehyde, which are insolubilized by heat, or they may consist of already formed resins such as dispersions of urea and formaldehyde resins, esters of acrylic or methacrylic acids and other rubber-like compounds, natural rubber latex, the resin obtained by mixing ammonium salts of salicylic and boric acids, or phosphonitrilic chloride. As examples of anti-felting reagents for the subsequent treatment are mentioned gaseous chlorine or bromine, solutions of hypochlorites or hypobromites, solutions of chlorine or bromine or alkyl hypochlorites in organic solvents, aqueous solutions of nitrogen-chloro derivatives, aqueous and non-aqueous solutions of caustic alkalis, sodium peroxide, strong organic bases, sodium sulphide, oxidising and reducing agents, or enzymic preparations. When using non-aqueous solutions, more prolonged treatment may be necessary. According to one example of the use of an "internal" resist, in which the resist is formed within the fibres, a fabric of cotton and wool is impregnated with a solution of 100 gms. of urea in 200 c.c. of 40 per cent. neutralized formaldehyde which has been allowed to condense for 3-6 hours and then diluted to 60 per cent. concentration and 2.3 3 per cent. ammonium dihydrogen phosphate added. The fabric is squeezed out, dried, and treated for 3 minutes at 130‹C. The material is then immersed in bleaching powder solution of 3‹ Tw. for ten minutes, squeezed, and the resin removed by decinormal hydrochloric acid followed by washing and drying. In another example, a solution is made by adding 40 parts of ammonium salicylate and 20 parts of ammonium borate in 250 parts of wat er and a k nitted wool fabric immersed in it, passed through a mangle, dried below 100‹C., and then heated to 110‹C. for 5 minutes. The treated fabric is then immersed for 10 minutes in sodium hypochlorite solution containing 5 per cent. available chlorine on the weight of the wool, washed, given an anti-chlor treatment, and dried. The ammonium borate resin gives a slightly yellowish brown colour. According to an example of the use of an external resist, 150 grms. of urea are mixed with 375 cc. of 40 per cent. formaldehyde and 15 grms. of hexamethylenetetramine. The mixture is raised to the boil and refluxed until turbidity no longer appears on cooling. It is then rapidly cooled and stabilized with 7 per cent. sodium acetate. This solution is diluted to contain 14 per cent. of solids and the wetted wool is then impregnated therewith, dried, and heated. The treated wool is then immersed for 45 mins. in sodium hypochlorite solution containing 5 per cent. chlorine, the ratio of liquor to cloth being 50 to 1. The material is washed, rinsed and dried. The increase in weight due to the urea-formaldehyde resin is 3.4 per cent.