| 摘要 |
1360348 Polyurethane artificial leathers TORAY INDUSTRIES Inc 19 April 1972 [19 April 1971] 18087/72 Heading B2E [Also in Divisions C3 and Dl] Non-woven fabrics may be impregnated and/or coated with a polyurethane elastomer prepared by reacting an organic diisocyanate with a linear copolymer diol prepared by condensing polytetramethyleneether glycol of M.W. at least 1000 with a dicarboxylic acid to form a prepolymer and reacting the prepolymer with a chain extender (see Division C3). The elastomer is preferably used as a solution in an organic solvent, and after impregnation and/or coating the solvent is evaporated or the fabric wet-coagulated. The fibres forming the fabric may be synthetic fibres such as polyamide, polyester or polyacrylate fibres or natural fibres such as wool or cotton or combinations of any of these. Blended fibres and islands-in-asea fibres are also useful. The non-woven fabrics are suitably prepared such that the number of needle barbs is from 1 to 9, the depth of the needle barb is from 30 to 200 microns and total number of punches is from 200 to 10,000 per sq. cm. The non-woven fabrics, particularly those derived from islandsin-a-sea fibres may be set with a water-soluble binder such as polyvinyl alcohol, starch or carboxymethylcellulose before impregnation and/or coating with the polyurethane elastomer. In the case of the islands-in-a-sea fibres the sea component of the fibre is extracted with a solvent before impregnation with the polyurethane elastomer. The impregnated and/or coated sheets may be dyed, sewed or subjected to shoe-making techniques. In specific Examples non-woven fabrics are prepared from polyethyleneterephthalate staple which fabric may have been fixed with polyvinyl alcohol or islands-in-a-sea fibres comprising polyethylenoterephthalate filaments distributed in a polystyrene sea-fibre, the fabric in the latter case being fixed with polyvinyl alcohol and the polystyrene component being extracted with perchloroethylene before impregnation with the polyurethane elastomer. |
