Flammability Characteristics of CO2 Blown Rigid Polyurethane Spray Foam

In view of the ozone depletion potential of HCFC-141b and other HCFCs, processing challenges with gaseous HFC-134a, and flammability potential with pentanes as blowing agents, significant efforts have been deployed in the development of environmentally friendly, all carbon dioxide blown rigid polyurethane spray foams. These foams are primarily used for the insulation of roofs, storage tanks, vessels, walls and piping. The Mannich base initiated Polyol A, developed by The Dow Chemical Company [1], with viscosity of ∼2000 cps at 77°F and OH# of ∼312 was manufactured using patented technology. This OH# is significantly lower than that of the dominating spray foam polyols (OH# 470). The low viscosity and higher equivalent weight of this polyol are designed to alleviate the processing difficulties of typical carbon dioxide blown spray applied systems.Some of the important requirements in spray systems are the flammability characteristics. Most carbon dioxide blown foams, however, suffer from high heat release,...