Bayer Materialscience Puts Environmentally Friendly Waterborne

Tag : PA Coating

Pittsburgh, PA - The outstanding properties of polyurethanecoatings have made them an up-and-coming segment of the coatingsmarket. The coatings industry's challenge now is to significantlyreduce the VOC levels in these coatings without sacrificing highproperty levels. Bayer MaterialScience LLC (BMS), a leader incoatings raw materials, has addressed this challenge by developingtechnology for the design of waterborne two-component (2K)polyurethane coating formulations with low emissions, yet the samerevered curing speeds and high protection levels as theirsolventborne counterparts.
In addition to their low emissions of organic solvents, waterborne2K polyurethane coatings are characterized by rapid curing at lowtemperatures and a good balance of resistance properties, filmappearance and mechanical strength. However, a challenge arisesfrom the fact that waterborne coatings in many cases lag behindsolventborne systems with respect to drying speed. To combat thisissue, BMS is developing new generations of polyol dispersions for2K polyurethane systems that exhibit improved physical drying andaccelerated chemical curing.
Christoph Irle, BMS AG, discussed these innovative formulations inhis poster presentation: Waterborne 2K PUR Coatings on the FastTrack. Irle, along with BMS co-authors Aaron Lockhart, Scott Graceand Ed Squiller, presented their overview at the recent 2008American Coatings Show and Conference in Charlotte, N.C.
The new generation of highly reactive polyol dispersions developedby BMS allows for the design of waterborne 2K polyurethane coatingformulations that exhibit significantly faster drying thantraditional systems. This innovative solution greatly increases theproductivity of low-VOC 2K polyurethane systems, opening the doorfor potential new markets, including site-applied, industrial andfast running roll-to-roll applications.
"Rapid growth in the 2K polyurethane coatings market is beingdriven by legislation, but also by end users demanding low solventemissions and low smell," said Irle. "Bayer's new generation ofpolyol dispersions will help pave the road to success for 2Kwaterborne polyurethane technology, and the continuous developmentof improved polyols and polyisocyanates will influence new marketstandards in environmentally friendly high-performance coatings."
The presentation highlighted a new proprietary technology thatincludes an internal activation of the chemical reaction betweenpolyisocyanate and polyol. The resulting reaction is completedsignificantly faster, while end properties and importantapplication parameters such as viscosity and pot life are notnegatively affected.
The authors explained that this new technology has already beensuccessfully implemented to accelerate formulations at low curingtemperatures, and to increase productivity of coatings processesunder forced drying conditions.