Patent GB-637656-A (GB)
Title: Improvement in art of stabilizing rayon type fabric
IPC: D06M11/71
Filed: 1947-03-17
Abstract: Textile fabric composed wholly or partly of regenerated cellulose or cellulose derivative filaments or fibres is rendered resistant to shrinking in subsequent laundering treatments, by subjecting a continuous length of the fabric while in open width and in slack condition longitudinally, to immersion in an aqueous solution of caustic alkali of 30-50 per cent strength at 20-60 DEG  C. for a period of not more than 10 seconds, squeezing out excess until the fabric retains 60-100 per cent of its weight of solution, neutralizing directly without prior dilution of the caustic alkali solution retained by the fabric, washing the fabric to free it from the neutralized impregnating agents, drying the fabric and adjusting as by framing to predetermined width.  As caustic alkali there may be used caustic soda, caustic potash, or lithium hydroxide.  Wool, cotton, regenerated protein, or other natural or synthetic fibres may be present in the fabric in addition to the regenerated cellulose or cellulose derivative fibres.  The fabric may be passed through a bath of caustic alkali solution and then squeezed on a padder or quetsch. Saturation of the fabric with the solution is hastened by adding a wetting agent such as a phenol dissolved in ethylene glycol butyl ether.  The squeezed fabric may be passed through the air in open width and then into a neutralizing bath, the total period from the entry into the caustic bath to entry into the neutralizing bath being about 5-50 seconds.  Dilute acids, e.g. acetic, hydrochloric, or sulphuric, or hot sodium bicarbonate solution may be used for neutralization.  The acid bath may be followed by hot or cold water baths.  If desired, protective agents such as sodium silicate may be added to the caustic alkali bath.  Substances for protecting the fibres from damage by the alkali may be applied from aqueous solution and dried on the fabric prior to treatment with the alkali.  As such protective agent there may be used an amphoteric metal salt, e.g. zinc sulphate, aluminium sulphate, sodium stannate with or without a buffer such as urea; a salt which represses ionization of the alkali, e.g. sodium or potassium borate, chloride, phosphate or sulphate, sodium benzoate, sodium naphthalene sulphonate, or a soap; a protective colloid such as methyl cellulose, salt of carboxymethyl cellulose, gelatine, or soya bean protein; a polyhydric alcohol such as glycol, glycerol or polyglycol; or urea.  Dyed or undyed fabric may be treated. After the alkali treatment and the neutralization, and washing, the fabric may be dyed under little or no tension and then dried. Specification 561,402 is referred to.ALSO:Textile fabric containing regenerated cellulose or cellulose derivative fibres, with or without other fibres such as wool, cotton, or regenerated protein fibres, is rendered resistant to shrinking in subsequent laundering treatments by subjecting a continuous length of the fabric while in open width and in slack condition longitudinally to immersion in an aqueous solution of caustic alkali of 30-50 per cent strength at 20-60 DEG  C. for a period of not more than 10 seconds, squeezing out excess until the fabric contains 60-100 per cent of its weight of the solution, neutralizing directly without prior dilution of the alkali retained by the fabric, washing, drying, and adjusting as by framing to predetermined width.  Caustic soda, potash, or lithia may be used. A wetting agent may be present, e.g. a phenol dissolved in ethylene glycol butyl ether.  The squeezed fabric may be passed through the air in open width and then into a neutralizing bath, the total period from the entry into the caustic bath to entry into the neutralizing bath being 5-50 seconds.  Dilute acetic, hydrochloric, or sulphuric acid, or hot sodium bicarbonate solution may be used for neutralization. Protective agents such as sodium silicate may be added to the caustic alkali bath.  Substances which protect the fibres from damage by the alkali may be applied from aqueous solution and dried on the fabric prior to treatment with the alkali. Specified protective agents are: amphoteric metal salts such as zinc or aluminium sulphate, or sodium stannate with or without a buffer such as urea; a salt which depresses ionization of the alkali, e.g. sodium or potassium borate, chloride, phosphate, or sulphate, sodium benzoate, sodium naphthalene sulphonate, or a soap; a protective colloid such as methyl cellulose, salt of carboxy methyl cellulose, gelatine, or soya protein; a polyhydric alcohol such as glycol, glycerol, or polyglycol; or urea.  Dyed or undyed fabric may be treated.  After the alkali treatment, neutralization, and washing, the fabric may be dyed under little or no tension, and then dried. Specification 561,402, [Group IV (a)], is referred to.