The Effect of Polyol Functionality on Water Blown Rigid Foams

Rigid foam processing and performance issues have all presented themselves as problems to be overcome as the polyurethane industry replaces chlorofluorocarbon (CFC) blowing agents with alternatives such as hydrochlorofluorocarbons (HCFC), hydrofluorocarbons (HFC), isomers of pentane and water. These problems include dimensional stability, foam flowability, formulation viscosity, friability, substrate adhesion, cycle times, cost, temperature resistance, insulation performance, k-factor aging, blowing agent solubility and flammability. Water blown rigid foams lack performance in many of these areas compared to the CFC blown foams of the past. Since much of the water blown rigid foam work of the past has been narrowly focused on individual applications and formulations, a broad study of the effect of polyol functionality on foam performance is necessary to address these issues.A series of five polyols, each having an equivalent weight of 110 glequiv, and functionalities ranging from two to six were prepared ...