| 摘要 |
<p>Textiles containing cellulose fibres are impregnated with formaldehyde solutions containing less than 10 per cent of formaldehyde and with stiffening or loading finishing agents from vegetable or animal colloids, or conversion products thereof, capable of forming condensation products with formaldehyde, and the impregnated materials are then subjected to a heat treatment at about 70-160 DEG C. in the presence of a catalyst having an acid reaction. Preferably, the impregnated materials are subjected to a drying treatment prior to the final heat treatment. The treatment reduces the swelling properties of the cellulose materials and improves the resistance to shrinking and stretching. At the same time the materials are stiffened and their resistance to abrasion is improved. Textile materials of natural or regenerated cellulose may be treated and they may be fabrics, yarns, or fibres, alone or mixed with other fibres. Formaldehyde or its polymers or hexamethylene tetramine which readily yields formaldehyde, may be used. The acidic catalyst may be an organic or inorganic acid of dissociation constant of about 3 X 10-1 to 10-4, or an acid salt of such acid, or an ammonium or other salt which dissociates at elevated temperature and gives an acid reaction. Buffer substances or swelling agents, e.g. zinc chloride, may be present during the treatment. The stiffening or loading agent may be starch, soluble starch, carob-bean flour, gum tragacanth, gum arabic, dextrin, sugar, or gelatine. Fabrics may be impregnated with the solution of formaldehyde and stiffening agent, squeezed, stretched in a stenter and maintained at the desired dimensions during the drying and heating treatments. The treatment improves the wet strength of artificial silks and staple fibres of regenerated cellulose. In an example, a viscose staple fibre fabric is impregnated with a solution containing soluble starch, formaldehyde, zinc chloride and potassium alum. It is removed from the solution and dried at 70 DEG C. It is heated to 130 DEG C., and then washed and dried. In another example, cotton fabric is treated with a solution containing wheat starch, formaldehyde, and aluminium thiocyanate. Dyed staple fibre gabardine is treated with a solution of tragacanth, formaldehyde and hydrochloric acid, and after the heat treatment is treated with water containing a fatty-alcohol sulphonate and sodium carbonate. Viscose voile is treated with a solution containing potato starch, formaldehyde, a cation-active softener and ammonium chloride. Tartaric acid and acetic acid are further examples of acidic catalysts. Reference has been directed by the Comptroller to Specification 452,150.</p> |
