By David Reed, UT EditorLeverkusen, Germany-Bayer MaterialScience AG has developed some high-solids, polyurethane dispersions (PUDs) for use in textile coating. Four basic products will be available under the Impranil tradename, according to a 1 Feb announcement from Bayer, which highlights the productivity improvements possible using the systems.All the products are free of organic co-solvents, thickeners and external emulsifiers and, with 60-percent concentrations, they offer end-users a number of advantages over the traditional polyurethane dispersions where solids contents are in the 35-50 percent range, Bayer claims. Above all, Bayer says, thicker coats can be produced in one application, significantly reducing costs through higher machine utilisation and lower energy consumption (in driving off the water present).All the new dispersions are non-reactive, but can be co-crosslinked either with suitable melamine resins or water-dispersible polyisocyanates to improve their fastness properties, the Bayer statement indicated.The Impranil DLU grade uses a polyurethane based on polycarbonate polytetramethylene glycol (PC-PTMG), which is noted for its high resistance properties. The product is compatible with the additives normally used in textile coating and was developed for the production of high-grade coatings for upholstery material. It can be mechanically foamed or processed as a compact coating, the Bayer statement added.The three other new PUDs are further developments of existing grades with a higher solids content of 60 percent. They are:* Impranil LP RSC 1380, suitable for the production of fashionable coatings and for the finishing of non-wovens. Apart from its higher solids content, its properties are similar to those of Impranil DLN;* Impranil LP RSC 1537 (its properties correspond to those of Impranil DLP-R) was developed primarily for the production of upholstery materials, car seats, sports goods and other technical products. It is outstandingly suitable for use as an anchor coat and constitutes an alternative to solvent-based products. * Impranil LP RSC 1554, whose properties largely correspond to those of Impranil DLS, is particularly suitable for mechanical foaming and for the production of fashionable articles and garments. "
