Bayhydrol PR 435 Aliphatic polyurethane resin Bayer MaterialScience Polyurethane (PU) - Polyurethane dispersions (PUDs) Coatings >> Waterborne Automotive refinishing >> Primer surfacer Bayhydrol PR 435 is an aqueous aliphatic polyurethane dispersion that contains only 5% by weight of organic cosolvent. Bayhydrol PR 435 polyurethane dispersion has been developed especially for the formulation of waterborne air-dry or force-dry automotive refinish primer-surfacers. Automotive primer-surfacers based on Bayhydrol PR 435 display fast drying, good early sandability, abrasion resistance, durability, and resistance to humidity. Aqueous aliphatic polyurethane dispersion. Contains an organic cosolvent. Used for the formulation of waterborne air-dry or force-dry automotive refinish primer-surfacers. Offers fast drying and good early sandability. Possesses abrasion resistance, durability and resistance to humidity.