Two – Component Polyurethane Coatings – High Performance Crosslinkers Meet the Needs of Demanding Applications

By Myron Shaffer, Raymond Stewart, Kathy Allen, Amy Wylie, Aaron Lockhart

Today’s waterborne polyurethane systems show equal, or sometimes even better, overall performance than comparable solventborne systems. Extensive resin design has taken place to allow 2K waterborne polyurethane systems to reach their current state of performance. Work had to be done on both the resin, or Bayhydrol® polyol portion, as well as the Bayhydur® polyisocyanate crosslinkers. Either research thrust would make for interesting reading. However, the focus of this report is to discuss the chemistry and development of the polyisocyanate crosslinkers that have been introduced from the early 1990s until today.

There are a number of properties important to coat­ings formulators. One of the important properties of coatings is their clarity and overall appearance. The im­po11ance of effectively dispersing an isocyanate crosslinker can be easily demonstrated simply by ob­serving the appearance of two similar systems.