GB741137A - Improvements in or relating to the treatment of cellulosic textile materials with polyisocyanates - Google Patents

Abstract

Cellulosic textile materials of modified properties are obtained by reacting them with polyisocyanates in the presence of a minor amount of one or more anhydrous inorganic salts of heavy metals. Specified polyisocyanates are ethylene-, hexamethylene- and dicyclohexyl-methane diisocyanates, and toluene-2 : 4 : 6-and triphenylmethane-4 : 41 : 411-triisocyanates. Reaction products of polyisocyanates which liberate the polyisocyanates under the conditions of the reaction such as the bisulphite adducts and the reaction products with compounds containing reactive methylene groups, e.g. acetoacetic esters, and the reaction products with phenyl urethanes, may also be employed. Specified heavy metal salts are calcium and ferric halides. The polyisocyanate may be applied as a vapour or as a solution or dispersion in an aqueous or organic liquid. The reaction may also be effected in the presence of a nitrogenous base such as urea, acetamide or melamine. Mechanical finishes, e.g. glazing, embossing and dimensional stabilization, on the textiles, may be rendered more permanent by effecting the reaction during or after the application of the mechanical finish (see Group IV (c)). The process is applicable to fibres of natural or regenerated cellulose or of cellulose esters or ethers, if desired in the presence of other fibres. Numerous examples describe the fixation of glaze effects on cotton fabrics, the heavy metal salts employed being cadmium iodide and ferric chloride and, in each case, the treated fabric is finally heated at 150 DEG C. to complete the reaction. Specification 656,643 is referred to.ALSO:Mechanical finishes, e.g., glazing, embossing and dimensional stabilisation, on cellulosic textile materials are rendered more permanent by reacting the materials, during or after the application of the mechanical finish, with polyisocyanates in the presence of a minor amount of one or more anhydrous inorganic salts of heavy metals, e.g., a cadmium or a ferric halide. The polyisocyanates may be applied before the mechanical finish in which case the reaction is effected by the conditions of the mechanical treatment or by a subsequent heating operation, or the polyisocyanates may be applied after the mechanical finish. Specified polyisocyanates are ethylene-, hexamethylene-, and dicyclohexylmethane - diisocyanates, and toluene-2:4:6- and triphenylmethane-4:41:411-triisocyanates. Reaction products of polyisocyanates which liberate the polyisocyanates under the conditions of the reaction such as the bisulphite adducts and the reaction products with compounds containing reactive methylene groups, e.g., acetoacetic esters, and the reaction products with phenyl urethanes, may also be employed. The polyisocyanate may be applied as a vapour or as a solution or dispersion in an aqueous or organic liquid. The reaction may also be effected in the presence of a nitrogenous base such as urea, acetamide or melamine. The process is applicable to fibres of natural or regenerated cellulose or of cellulose esters or ethers, if desired in the presence of other fibres. Numerous examples describe the fixation of glaze effects on cotton fabrics, the heavy metal salts employed being cadmium iodide and ferric chloride, and in each case the treated fabric is finally heated at 150 DEG C. to complete the reaction. Specification 656,643 is referred to.