Patent GB-1390318-A (GB)
Title: Process for the wrinkle resistance and other properties of  cellulosic fibre-containing fabric
IPC: D06M15/423
Filed: 1973-03-06
Abstract: 1390318 Durable press process COTTON INC 6 March 1973 [28 March 1972] 10773/73 Heading D1P The dimensional stability, wrinkle resistance, smooth drying characteristics and total shape retentivity of cellulosic fibre-containing fabric such as cotton fabric, are improved by post-heating the fabric to above 100‹C after treatment with acetic acid or formic acid vapours following impregnation of the fabric with an aqueous solution of a watersoluble crease-proofing agent containing reactive N-methylol groups such as methylolated melamine or cyclic methylol ureas. The contacting with the acid vapours, which may be pure or admixed with inert gases such as air, nitrogen, carbon dioxide, helium or steam, is effected at between 80‹C and 160‹C, preferably from 110-125‹C, for a time of between 10 seconds and two hours, preferably from 2-15 minutes. Prior to treatment with the vapours, the impregnated fabric may be conditioned to a moisture content of between 2 and 100%, preferably 3-65% by weight. Specified creaseproofing agents include trimethylol melamine, methylated methylol melamine, dimethylol dihydroxy ethylene urea, dimethylol propylene urea, dimethylol uron, dimethylol carbamate and condensation products of formaldehyde with urea or a phenol such as resorcinol. The fabric may be additionally treated, prior to the acid vapour catalytic treatment, with a dispersion or latex of a polymeric softening agent such as polyethylene, acrylonitrile-butadiene copolymer, urethane latex, diacetylated copolymers of ethylene and vinyl acetate, polyesters and polyamides. The softening agent may be added to the creaseproofing solution. The fabric preferably contains at least 20% of natural or artificial cellulosic fibres such as those of cotton, linen, hemp, viscose rayon and cuprammonium rayon. These fibres may be blended with each other or with fibres such as those of cellulose acetate, polyamides, polyesters, polyacrylonitrile, polyolefins, polyvinyl chloride, polyvinylidene chloride and polyvinyl alcohol. The fabric may be knitted, woven or non-woven and may be flat, creased, pleated, hemmed or sewn, e.g. to produce a garment. The fabric may be contacted with the acid vapours by a batch system utilising a closed vessel or tube containing the gaseous catalyst and into which the fabric may be placed, or by a continuous process wherein a gas stream containing the acid vapours is passed through a closed elongated chamber through which the impregnated fabric is passed either concurrently or counter-currently relative to the gas. Alternatively the gas stream may be passed over a stationary fabric. In the Examples a cylindrical aluminium vessel heated with band heaters under thermostatic control and having means for circulating its gas content through an external recycle line is used as a reactor for contacting the fabric with acid vapour. Operation is preferably at approximately atmospheric pressure. The acid vapour is generated by dropping an 85% aqueous formic acid solution into an evaporating dish in the bottom of the reactor.