GB672673A - Improvements in or relating to a process for finishing natural and regenerated cellulose fabrics - Google Patents

Abstract

Fabrics of cellulose and regenerated cellulose and mixtures thereof are impregnated with a 5 to 20 per cent by weight aqueous solution of water-soluble, acid-catalyzable, thermo-setting resin-forming materials, water-insoluble after hardening, containing a minor amount of an acidic or potentially acidic catalyst, the solution pick-up being 70 to 90 by weight on the dry fabric, then dried until substantially devoid of free moisture, cooled to room temperature, passed through a mechanical finishing pressure calender at a temperature such that the fabric is heated to a temperature between 100 DEG and 200 DEG F. and preferably below 175 DEG F. and then cured in an atmosphere of from 250 DEG to 350 DEG F. for 8 to 2 minutes. Suitable resin-precondensates include melamine-formaldehyde, urea-formaldehyde, thiourea-formaldehyde, dicyandiamide-formaldehyde and mixtures thereof. Glyoxal may be substituted for formaldehyde. It is important that no polymerization of the resin-forming materials should occur during the mechanical finishing. The catalyst may constitute 3-5 per cent by weight of the solid resin-forming materials, and it is preferred that it should have a pH on the dried fabric at a temperature of about 212 DEG F. of 6 to 8, but develop high acidity at higher temperatures. Ammonium hydroxide may be added to the impregnating solution to maintain neutrality during the drying. Suitable catalysts are carbazide hydrochloride, phenyl biguanide hydrochloride, monoguanyl urea phosphate, dimonoethanolamine hydrogen phosphate, and octadecyloxymethyl pyridinium chloride. The impregnating bath may contain a cation-active permanent softener such as octadecyloxymethyl pyridinium chloride when treating cotton materials or a water-removable softener such as carbowax when treating regenerated cellulose materials. The preferred amount of softener is from 1 to 4 per cent by weight of solution. Any mechanical finishing treatment may be applied to the fabric. In an example a cotton fabric is impregnated with a solution comprising 40 lbs. of melamine-formaldehyde precondensate (80 per cent solids), 20 lbs. urea-formaldehyde precondensate (50 per cent solids), 10 lbs. softener, 4 lbs. monoguanyl urea phosphate, 1 lb. of 28 per cent ammonium hydroxide and water to make 100 U.S. gallons. The impregnated fabric is squeezed to give a solution pick-up of 70 per cent and dried at 350 DEG F. until approximately 6 per cent moisture (natural) remained therein and quickly cooled to 65 DEG F. It is then chase-calendered in a five-bowl calender, the steel bowls of which are heated to 250 DEG F. After curing for 2 minutes at 350 DEG F. it is washed and dried. Specification 672,674 is referred to.