GB844943A - Treatment of rayon - Google Patents

Abstract

Textile materials consisting of rayon, i.e. regenerated cellulose of either the viscose or cuprammonium type or cellulose esters, e.g. cellulose acetate, are de-oiled and desized by passing them, preferably in open width, through one or more baths of a solvent, namely trichloroethylene or perchloroethylene, preferably at elevated temperature, eliminating solvent entrained in the materials by subsequently passing them through an aqueous medium maintained at an elevated temperature sufficient to flash off the solvent, then passing the materials through an aqueous alkaline solution of a peroxygen compound at a pH of at least 11, and subsequently steaming to promote desizing. The solvent treatment is preferably carried out for 10 seconds to 5 minutes at 80 DEG -87 DEG C. in the case of trichloroethylene and at 110 DEG -120 DEG C. in the case of perchloroethylene. The aqueous flashoff bath is maintained at a temperature of at least 73 DEG C. in the case of trichloroethylene and at least 86 DEG C. in the case of perchloroethylene and in either case preferably at 90 DEG -95 DEG C., the time of contact being 8-60 seconds. Suitable peroxygen compounds are sodium peroxide, sodium percarbonate and hydrogen peroxide, alkaline peroxide solutions of pH 11 to 12 having an available oxygen content equal to that of a solution containing 3 to 15 grammes per litre of sodium peroxide being preferred. The peroxide solution preferably contains a stabiliser, e.g. an alkali-metal silicate, and an anionic or non-ionic wetting agent. After leaving the solution of the peroxygen compound the material preferably retains 1-2 times its own weight of liquor and is subsequently steamed for 1-3 minutes. Specification 812,893 is referred to