Patent GB-323785-A (GB)
Title: Improvements in the production of waterproof materials
IPC: D06M13/188
Filed: 1928-08-07
Abstract: 323,785. British Celanese, Ltd., and Ellis, G. H. Aug. 7, 1928. Addition to 323,501. Yarns, treating with liquids.-Materials formed of or containing organic substitution derivatives of celluloses such as " immunized cotton," cellulose acetate, formate, propionate, butyrate or other ester, and methyl, ethyl, benzyl or other cellulose ether are waterproofed by treating them with an emulsion of wax in a soap solution and precipitating the soap in the material in the form of an insoluble metallic soap, the metallic radicle being applied while the cellulose derivative is in a swollen condition. This treatment also subdues the lustre of the material. The precipitating solutions may comprise chlorides, sulphates or thiocyanates of tin, aluminium calcium, barium, lead, iron, chromium, bismuth, zinc or antimony and they may be applied before or after the wax emulsion. The metallic solution itself, as in the case of thiocyanates, may act as the swelling agent, the metallic solution being applied in such concentration or under such conditions as to produce the swelling of the cellulose derivative as described in the parent Specification. Or a separate swelling agent may be employed either before or during treatment with the metallic solution, and such separate swelling agent may be employed even though the metallic solution itself acts as a swelling agent, as, for example, in the case of a concentrated solution of a chloride. Alternatively, the metallic radicles may be incorporated in the spinning solution used for the manufacture of the filaments &c. Suitable swelling agents, particularly in aqueous solution, are acetic, formic, glycollic or lactic acids ; ethyl alcohol, acetone, diacetone alcohol or diacetin; phenol, hydroquinone or other water soluble phenols or polyhydric phenols; thiocyanates or cyanates and urea, urethanes, thiourea, thiourethanes, guanidine or alkyl or other simple derivatives thereof. Such swelling agents may be added to the solutions of the metallic compounds or they may be used previous to treatment with such solutions. The waxes specified are Japan wax, Carnauba wax, osokerite and beeswax and the soaps include, in addition to fatty acid salts, salts of sulphonated fatty acids or oils, resins, naphthenic acids and other soap forming substances and the free acids themselves. The material may be coloured before or after waterproofing or dyestuffs may be incorporated in the wax emulsions if soluble therein so as to colour and waterproof the material simultaneously. In an example, cellulose acetate fabric is steeped at 45‹ C. for 15 minutes in an emulsion of 5 grams of Japan wax, 5 grams of soapflakes and 30 c.cs. of ammonia (S.G. 0.880) per litre and is then lifted, squeezed evenly and then worked for 10 minutes in a 5' Tw. aluminium acetate solution at 20‹ C. In another example, cellulose acetate fabric is padded at 30‹ C. in a solution of tin chlorothiocyanate (3 parts stannic chloride and 1 part of ammonium thiocyanate dissolved in the least quantity of water and diluted to 42‹ Tw.). The goods are then batched for 3 hours at 30‹ C. and then, without rinsing, treated for 15 minutes at 45‹ C. in an emulsion of 5 grams of Carnauba wax and 5 grams of soapflakes per litre and then washed till free from thiocyanate and dried or otherwise treated. Treated in this way the fabric acquires a subdued lustre which may be modified to a greater degree by raising the temperature of the soap bath.