SHRINKPROOFING WOOL WITH OXIDIZING AGENTS USING FOULARD LIQUID APPLICATION TECHNIQUE

摘要

Wool and wool-containing materials in a continuous length, e.g yarns, tops and woven and knitted fabrics, are shrink-proofed by wetting them out with an aqueous liquor containing (a) a wetting agent, e.g. an anionic or nonionic wetting agent, (b) a halogen-containing shrink-resistance-imparting oxidising agent for wool, e.g. sodium or potassium dichloroisocyanate or an alkali metal hypohalite, and (c) a source of hydrogen ion other than a per acid in an amount sufficient to reduce the pH value of the liquor to below 5, the anion of the source of hydrogen ion being inert with respect to the halogen-containing oxidising agent, immediately after wetting out passing the wetted-out material through the nip between a pair of rollers to ensure that the material is uniformly impregnated with a controlled amount of the liquor while maintaining the controlled amount of the liquor in contact with the material until at least a desired amount of the halogen-containing oxidising agent has reacted with the wool and feeding metered quantities of aqueous solutions of the halogen-containing oxidising agent, the wetting agent and of the source of hydrogen ion into the aqueous liquor to maintain a substantially constant composition, the quantities being correlated with the rate of pickup of liquor by the woollen materials being treated so that (a) the volume of liquor remains substantially constant and (b) complete renewal of liquor takes place in 1-15 minutes. The source of hydrogen ion may be hydrochloric, sulphuric, acetic or trichloroacetic acid, sodium or potassium hydrogen sulphate or sodium dihydrogen phosphate. The material may be wetted with the aqueous liquor either by immersion for 1-2 seconds or by spraying and the pickup of aqueous liquor or the nip may be 50-250%. The treated material may subsequently be washed with water, passed through a dilute aqueous solution of a reducing agent, e.g. sodium sulphite, again washed with water and finally dried.