| 摘要 |
<p>Non woven fabrics a portion at least of which consists of water soluble polyvinyl alcohol fibres are rendered resistant to the action of cold and hot water and dry cleaning solvents, e.g. trichloroethylene, by impregnating them with an aqueous solution of an aminoplast precondensate and a catalyst and drying them. The amount of aminoplast resin taken up by the fabric amounting to up to 5% of the dry weight of the polyvinyl alcohol fibres. The aminoplast precondensate used is trimethylol melamine, tetramethylol acetylene diurea, dimethylol dihydroxyethylene urea, dimethylol urea or other precondensate of an aldehyde, e.g. formaldehyde or acetaldehyde, with urea, Thiourea or a sulphonamide. Suitable catalysts are ammonium chloride, magnesium chloride, zinc chloride, ammonium oxelate and hydrochloric and sulphuric acids. The non woven fabrics may comprise polyvinyl alcohol fibres in admixture with viscose rayon, cotton and "Perlan" (Registered Trade Mark) fibres. Specification 876,444 is referred to.</p> |
