Present Status and Development Trend of Waterborne Polyurethane Resins and Coatings in China

摘要

Since the first polyurethane (PU) resin was prepared by professor Otto. Bayer in 1937, the PU resins have been widely used in various industries because of its excellent chemical and mechanical properties. But most of the solvent-based polyurethane coatings contain large amount organic solvents and a certain amount free-isocyanates, which will exert a negative effect on human's health and living environment. Along with the strict regulations for environment protection in the world, the waterborne polyurethane has been come into use in many industries, such as textile, leather, adhesive and coatings industries. In 1967, the PU emulsion was first commercialized in U.S. In 1977, Bayer first used the PU emulsion as the finishing on leathers, and the waterborae PU products start to become a sort of important commercial products. In late 70s' last century, the blending mixture of waterborne PU and acrylic emulsion came into practical application. And in 80s', the hybrid of acrylic-polyurethane dispersion found its application in industry. In 90s', some companies in Europe and North America developed one-pack self-crosslinking aqueous polyurethane system and followed by the successful achievement of waterborne UV-curing polyurethane resin, which has not yet found practical applications in industry. Successively some companies, such as Bayer and Rhodia developed the aqueous dispersion of isocyanate hardener, which promoted the development and progress of two-pack aqueous polyurethane coatings and its application in practice, and improved the film properties of aqueous PU coatings, which are close to that of solvent-based two-pack PU coatings film, but still need plenty of working for its applications. In European or North American countries, the waterborne PU resins have being widely used in textile, leather, wood, plastics, metals, and concrete industries, and the Aqueous PU coatings are also widely used in textile, leather manufacturing, adhesives, shoes making, wood furniture, and auto industries.