Emission-free polyurethane dispersions

Bayer MaterialScience has launched new cosolvent-free PU dispersions for waterborne environmentally friendly two-component PU coatings. The coating films made using Bayhydrol U dispersions display properties, ranging from hard through to flexible and a velvety soft feel.

Coatings based on Bayhydrol U XP 2750 are hard, yet elastic, even in cold conditions, and are also very scratch-resistant. By incorporating self-healing segments into the polymer, the coating is able to realign itself after being scratched. In addition, coatings based on Bayhydrol U XP 2750 have a high-gloss finish, are weather-stable and are very resistant to chemicals. The dispersion is ideal for clear coats and topcoats applied to metal and plastic substrates.

The aqueous binder Bayhydrol U XP 2755 was designed for two-component PU systems for industrial wood and furniture coatings. As this highly reactive dispersion produces coatings that dry very rapidly, the coated parts can be stacked or used very quickly. Despite its quick-drying properties, the low minimum film-forming temperature of the product means it can be used to produce coatings with very low cosolvent content. These films are distinguished by their high level of hardness and gloss, grain accentuation on the wood surface, good mechanical strength and resistance to chemicals. In addition, these coatings offer a pot life of over six hours.

Bayhydrol U XP 2757 was developed specifically for waterborne soft feel and comfort coatings. These types of coating can transform e. g. cold plastics into surfaces that have a soft, warm and pleasant feel. Compared to an earlier generation of NMP-free PU dispersions, the new product offers improvements in the coating’s resistance to chemicals. The new dispersion is also suitable for wood and furniture coatings, an area of application that still represents new ground for soft feel coatings. This gives the wooden surface a pleasantly dry, natural feel that is barely distinguishable from that of uncoated wood. However, unlike untreated wood, these coated surfaces are water-repellent and resistant to any discoloration that could be caused by coffee or red wine, for example.