pu-655 hdi hydrophilic aliphatic polyisocyanate curing agent component for aqueous two-component polyurethane systems a-a+ model no. pu-655 type hydrophilic aliphatic polyisocyanate based on hexamethylene diisocyanate (hdi) curing agent component for aqueous two-component polyurethane systems description of pu-655 pu-655 is a crosslinking agent for aqueous systems, which require good binding stability and chemical resistance. uses due...