Patent GB-601167-A (GB)
Title: Improvements in or relating to process of rendering textile fabrics resistant to shrinking and creasing, and the improved textile fabric resulting therefrom
IPC: D06M15/423
Filed: 1945-05-29
Abstract: Textile materials are rendered resistant to shrinking and creasing by impregnating them with an aqueous solution of an infinitely water-soluble substantially monomeric methylol melamine condensation product which out of solution is substantially amorphous in character, said aqueous solution being supplied in sufficient amounts to deposit in the fabric about 1-15 per cent by weight of the condensation product based on the dry weight of the material, and thereafter drying and curing the condensation product.  The methylol melamine condensation product may be obtained by reacting melamine and aqueous formaldehyde solutions, containing 30-40 per cent of formaldehyde by weight, in ratios of 2-6 mols. of formaldehyde for each mol. of melamine. The reaction is carried out until a clear solution is obtained, usually 2-10 minutes.  The temperature should be at least 70 DEG  C. to avoid formation of crystals of low solubility but it should preferably be no higher than 90 DEG  C. to avoid premature polymerization.  The clear solution is spray dried at 70 DEG  C. or higher to form a solid, amorphous, water-soluble product.  The condensation is preferably carried out at a pH of 8.8-9.5 using sodium or ammonium hydroxide, or quaternary ammonium bases to adjust the pH.  A small amount of catalyst such as di-ammonium hydrogen phosphate, urea oxalate, di-ammonium phthalate, ammonium chloride, or ethyl ammonium phosphate, may be added to the solution immediately before the solution is applied to the fabric. After drying the treated material, the condensation product may be polymerized and rendered insoluble by heating to 225 DEG -300 DEG F.ALSO:An aqueous solution of an infinitely water-soluble substantially monomeric methylol melamine condensation product which out of solution is substantially amorphous in character, is prepared and used for impregnating textile materials.  The methylol melamine condensation product may be obtained by reacting melamine and aqueous formaldehyde solutions containing 30-40 per cent of formaldehyde by weight in ratios of 2-6 mols. of formaldehyde for each mol. of melamine.  The reaction is carried out until a clear solution is obtained, usually 2-10 minutes.  The temperature should be at least 70 DEG  C. to avoid formation of crystals of low solubility, but it should preferably be no higher than 90 DEG  C. to avoid premature polymerization.  The clear solution is spray dried at 70 DEG  C. or higher to form a solid, amorphous, water-soluble product.  The condensation is preferably carried out at a pH of 8.8-9.5 using sodium or ammonium hydroxide, or quaternary ammonium bases to adjust the pH.ALSO:Textile materials are rendered resistant to shrinking and creasing by impregnating them with an aqueous solution of an infinitely water-soluble substantially monomeric methylol melamine condensation product which out of solution is substantially amorphous in character, said aqueous solution being supplied in sufficient amounts to deposit in the fabric about 1-15 per cent by weight of the condensation product based on the dry weight of the material, and thereafter drying and curing the condensation product.  The treatment may be applied to natural, regenerated, or esterified cellulose fibres or fabrics, e.g. cotton, linen, viscose rayon, cellulose acetate, silk, mohair, or wool.  The tendency of woollen materials to felt is reduced.  The methylol melamine condensation product may be obtained by reacting melamine and aqueous formaldehyde solutions containing 30-40 per cent of formaldehyde by weight in ratios of 2-6 mols. of formaldehyde for each mol. of melamine (see Group IV (b)). A small amount of catalyst such as di-ammonium hydrogen phosphate, urea oxalate, di-ammonium phthalate, ammonium chloride or ethyl ammonium phosphate may be added to the solution immediately before application to the fabric.  The textile material may be sprayed or padded with the solution or immersed in the solution and then passed through squeeze rollers.  After drying the treated material, the condensation product may be polymerized and rendered insoluble by heating to 225-300 DEG  F.  In examples, cotton fabric, spun rayon fabric, wool flannel and dress goods containing cotton warp and wool and mohair weft are immersed or padded with a solution of amorphous tetramethylol melamine, and then subjected to drying and curing treatments.