| 摘要 |
To reduce its tendency to shrink in aqueous liquids textile material composed wholly or partly of wool is first impregnated with an aqueous solution containing permonosulphuric acid or a salt thereof, at a pH less than 8.0, followed by impregnation with an aqueous solution containing a salt of sulphurous acid, or of compounds which produce such a salt in solution. A normal, acid or basic sodium, lithium, potassium, aluminium, barium, calcium, magnesium, manganese, strontium, zinc or ammonium salt of sulphurous acid or mixtures of such salts may be employed. In an example a basic aluminium sulphite is produced by dissolving sodium sulphite, ammonia and potassium alum in water. The pH of the first bath may be adjusted by adding sulphuric acid or sodium hydroxide. Wetting agents may also be added. In examples, the second bath comprises an aqueous solution of sodium sulphite; sodium sulphite and sodium carbonate; sodium sulphite, zinc sulphate and ammonia; potassium bisulphite; calcium sulphite; magnesium sulphite; manganese sulphite. When the first bath is acidic and an acid sulphite is used for the second bath, the material may be rinsed or neutralized, e.g. with a solution of sodium carbonate, between the impregnations. The temperature of the first bath may vary up to 70 DEG C. and of the second bath up to 100 DEG C. The solutions may be applied by immersion, padding or spraying. In example 14 a wool top is passed through a five bowl backwasher the bowls of which contain (1) an aqueous solution of permonsulphuric acid, a wetting agent and sulphuric acid, (2) an aqueous solution of sodium sulphite and sodium bicarbonate, (3) an aqueous solution of acetic acid (4) and (5) running water rinses. Specification 692,258 is referred to. |
