Patent GB-547846-A (GB)
Title: Improvements in or relating to the aldehyde treatment of cellulosic textile materials
IPC: D06M15/423
Filed: 1940-02-22
Abstract: 547,846. Treating textiles with liquids etc.; cellulose derivatives. AKT.-GES. CILANDER. Feb. 22, 1940, No. 3379. Convention date, March 4, 1939. [Classes 2 (ii) and 15 (ii)] Textiles containing natural or artificial cellulosic fibres are subjected to the action of compounds containing aldehyde-groups in the presence of etherifying or esterifying agents and in the presence of catalysts. A sufficiently large proportion of aldehyde is used and the final reaction treatment is carried out at such a relatively high temperature that the main reaction which takes place is an aldehydecellulose reaction (Sthenosage). Fibres or yarns so treated may be woven or knitted with untreated yarns and the material so obtained may be treated with direct dyes or subjected to a shrinking treatment so as to obtain pattern or crepe effects. Before the final reaction treatment, the materials may be subjected to a shaping operation to impart a desired pattern or specified surface dimensions. The treatment results in products of increased strength in wet condition, decreased tendency to swell in acid, alkali, or salt solutions, increased resistance to shrinking and creasing, and increased ability to maintain the shape or form imparted by' calendering, stamping, ruffling, and like treatment. The dyeing affinity of the treated materials is modified. Pattern effects may be obtained by applying the treatment in selected areas. The treatment does not result in any substantial loss of extensibility. The treatment with aldehyde may be followed by a drying and by a further heat treatment. Aliphatic or aromatic aldehydes, polyaldehydes, aldehydic acids, aldehyde alcoholates, aldehyde bisulphites, and compounds capable of splitting off aldehydes, may be used. Formaldehyde, acetaldehyde, paraldehyde, trioxymethylene, glyoxal, hexamethylene tetramine, methylal, glucose, glycerine aldehyde, benzaldehyde, benzaldehyde sulphonic acid, benzaldehyde carboxylic acid, chloral, methylene carbamide, or products of aldehydes with sulphites, polysulphides, ammonium sulphide, or thiocyanates, are specified. The catalyst may be boric, lactic, succinic, acetic, chloracetic, formic, oxalic, benzene sulphonic, sulphanilic, an amino naphthol sulphonic, or a naphthol sulphonic acid, or ammonium sulphate, ammonium thiocyanate, a phosphate, persulphonate, a chlorsulphonate, aluminium chloride, silicon tetrachloride, or aluminium acetate. The esterifying or etherifying agent may be a solution, dispersion, or emulsion of an organic or inorganic acid anhydride or chloride. It may be a pyridinium or oxymethyl pyridinium compound containing radicals of acids particularly of saturated or unsaturated higher fatty acids of more than 10 carbon atoms or aromatic acids or containing. radicals of derivatives or substitution products of acids. It may be the substance sold under the Registered Trade Mark " Velan," or a similar pyridinium chloride compound in which instead of the radical of.a higher fatty acid, there is present the radical of another acid, e.g. of nitrobenzoic acid. The reaction with aldehyde may be effected in presence of a small amount of a substance which acts as a buffering or transmission agent for the aldehyde. For this purpose there may be used urea, thio-urea, methylene urea, compounds of aldehydes with polysulphides or thiocyanates, or lower condensation products of sulfine resins. The impregnating liquids may also contain starch, gelatine, glucose, methyl cellulose, rubber, synthetic rubber, dyes, pigments, fillers, wetting agents, water repelling agents, and other ingredients. Drying subsequently to the impregnation may be carried out with the materials in stretched or relaxed condition. The process is applicable to flocks, yarns, fabrics, hosiery, or felts. The cellulosic fibres may be mixed with animal fibres or artificial resin fibres. In an example, cotton flock is soaked with a solution of formaldehyde, "Velan PF," dimethylol urea, ammonium sulphate, and sodium acetate, and is centrifuged, dried, and then heated for several minutes. The flock is used as a nop for spinning with cotton to form a yarn or fabric which on dyeing gives a nop colour effect. Cotton yarn is impregnated with formaldehyde, "Velan," sodium acetate, and sodium persulphate solution, dried, and heated. Crepe effects are produced in a mixed fabric containing treated and untreated yarns by submitting it to the action of alkaline or acid shrinking agents. Viscose artificial silk fabric is impregnated with a solution of formaldehyde and soap-stearic anhydride emulsion and then sprayed with a solution of oxalic acid and ammonium persulphate. It is then dried and heated. The fabric is crease-proof and water-repellant. Specification 25647/06, [Class 2], is referred to.