GB526098A - Improved process for the finishing of cellulosic textile materials - Google Patents

Abstract

526,098. Treating textiles with liquids. CALICO PRINTERS' ASSOCIATION, Ltd., LANTZ, L. A., and MILLER, W. S. Dec. 7, 1938, No. 35661. [Class 15 (ii)] Cellulosic textile yarns or fabrics are rendered resistant to shrinkage on washing and extension when damp without at the same time becoming resistant to creasing, by impregnating them with so much of a solution of formaldehyde and an acid at a pH value of not more than 2 that after drying the material so as to cause a reaction between the cellulose and formaldehyde there is fixed on the treated material, after washing and drying, not less than 0.5 per cent. and not more than 1.75 per cent. of formaldehyde in the case of regenerated cellulose and not less than 0.1 per cent. and not more than 0.4 per cent. formaldehyde in the case of natural cellulose fibres, the material during the drying operation being kept at or slightly over the final dimensions until completely dry. Treatments in which embossing, glazing or similar mechanical treatment is effected subsequent to impregnation but before the heat treatment, or in which the impregnation is carried out for a period of two hours or more, are excluded. The concentration of formaldehyde may be 15 per cent. or less. The acid used may be sulphuric, nitric, phosphoric, phosphorous, pyrophosphoric, hydroxymethane sulphonic, trichloroacetic, oxalic, maleic, malonic, chloracetic, tartaric, or citric acid. Instead of the free acid a substance which liberates acids on heating or by reaction with the formaldehyde, e.g. cyclohexylamine perchlorate, may be used. The temperature of drying may be 60-130‹C. Unfixed formaldehyde is removed by washing in weakly alkaline solution. In examples viscose crepe fabric is treated with a solution containing 5-15 per cent. of formaldehyde and 2.5 per cent. of tartaric acid or 2 per cent. of phosphoric acid, or 1 per cent. of nitric acid, and squeezed till 108 per cent. of solution remains in the cloth. Drying is effected at 70-110‹C. for a few minutes. In another example, cotton fabric is impregnated with a solution containing 3 per cent. of formaldehyde and 0.13 per cent. of sulphuric acid, squeezed until 70 per cent. of solution remains in the cloth and dried at 105‹C. Specifications 452,150 and 477,084 are referred to.