Bayer MaterialScience puts its deep understanding of polyurethane chemistry into the development of waterborne 2K systems for automotive finishing, commercial vehicle and general industrial coatings
Whereas in the past performance and appearance were the main market requirements in automotive refinishing, commercial vehicle and general industrial coatings, there is now an additional focus on reduced emissions – and thus on waterborne 2K polyurethane coatings. The secret of successful raw material development lies in a deeper understanding of 2K chemistry, and here, Bayer MaterialScience can point to unparalleled know-how.
In order to restrain the concurrent reaction of isocyanate groups with water in formulating waterborne coatings, the designs of the polyisocyanate hardeners and polyol dispersions have to be matched. Besides, a coordinated synthesis of a suitable polyol-polyisocyanate combination is crucial for effective emulsion resulting in homogeneous hardener distribution with low particle size in the polyol dispersion. We have both PIC crosslinkers and polyol dispersions in our portfolio – and the necessary know-how to ensure a perfect match in 2K polyurethane formulations.
High functionality and low viscosity
Low-viscosity polyisocyanates from the Desmodur® product range are easy to emulsify and mix with suitable Bayhydrol® polyols and deliver an excellent film performance. Desmodur® N 3900, for example, has set new standards in “green” 2K polyurethane coatings with its low viscosity (730 mPas), high average functionality (>3), easy mixability and very good crosslinking performance. As a crosslinking reactive thinner with a viscosity of under 100mPas, Desmodur® XP 2730 is the ideal solution for low or zero VOC formulations and for lowering the viscosity of the isocyanate component and improving emulsification – as described in AdCoTec issue 1-2010.
Easy to mix for an excellent coating The Bayhydur® product range – water-dispersible polyisocyanates with an integrated emulsifier function – feature a patented waterborne crosslinking technology for perfect emulsification with little need for stirring. The difference between Bayhydur® and competing products with an external emulsifier is that the emulsifier function is permanently anchored to the polymer chain, ensuring a homogeneous spread and an excellent, ultra-stable coating layer. The Bayhydur® range covers products with low viscosity and low VOC, higher chemical or weather resistance, fast drying qualities, or higher performance and robust processing. One of the most recent additions, IPDI-based Bayhydur® XP 2759, combines fast drying with chemical resistance. But whatever waterborne 2K polyurethane applications are required, we have the system competence to deliver the right HDI- or IPDI-based components.
For a face-to-face discussion of your individual questions and needs please get in touch with your regular contact persons at our distribution partners or at our local agents.
