Bayhydur 303 is a solvent-free, water-dispersible polyisocyanate resin based on hexamethylene diisocyanate (HDI). Properties / Applications: Bayhydur 303 polyisocyanate is a solvent-free, water-dispersible crosslinking agent for hydroxyl- function waterborne resins. It is dispersed in the aqueous resin by direct addition and simple agitation, just prior to use. Reaction occurs under ambient conditions. The pot life varies with the aqueous resin used, but can be several hours in duration. After the polyisocyanate has been added to the waterborne component, the container should not be hermetically sealed, since a pressure buildup may occur due to carbon dioxide formation. As with any product, use of Bayhydur 303 in a given application must be tested (including but not limited to field testing) in advance by the user to determine suitability. Information provided by Covestro |