Leverkusen, Germany - Bayer MaterialScience has introduced a new generation of co-solvent-free polyurethane dispersions (PUDs) in an effort to make coating technology more 'green.' The company claims the dispersions are "further improving the performance of waterborne environmentally friendly two-component polyurethane coatings for various substrates."
Made from Bayhydrol U dispersions, the film coatings display properties ranging from hard through to flexible and soft, BMS said in a 6 Jan announcement.
"The new polyurethane polyols contain no N-methy-2-pyrrolidone or any other cosolvents," BMS raw materials expert Martin Melchiors said in a presentation at the recent European Coatings Conference. Melchiors said the polyols offer "considerable potential" in the formulation of waterborne two-component PU coatings and "are superior in many ways to the polyacrylate dispersions that have been most commonly used up till now," he added.
Coatings based on Bayhydrol U XP 2750 are scratch-resistant, hard, and elastic - even in cold conditions, BMS said. To create scratch resistance, experts at BMS incorporated self-healing segments into the polymer so it can realign itself after being scratched, the statement said. Ideal for clear coats and topcoats, the PUD is weather-stable, resistant to chemicals and has a high gloss finish and applied to metal and plastic substrates, the German chemical company said.
Used in two-component PU systems for industrial wood and furniture coatings, aqueous binder Bayhdrol U XP 2755 produces rapid drying coatings but still has a low temperature for minimum film-forming and so can be used to produce coatings with extremely low co-solvent content, BMS said. The films create a high level of hardness and gloss with a pot life of over six hours, the company added.
Finally, Bayhydrol U XP 2757, which is a co-solvent-free dispersion for waterborne wood and furniture coatings, gives a soft, "comfort" feel, the statement said. The coating, which is water-repellent, gives a natural dry feel that is "barely distinguishable" from uncoated wood, BMS claims. (RD)