Techniques to Assess the Various Factors Affecting the Long Term Dimensional Stability of Rigid Polyurethane Foam

CFC blowing agents have been eliminated from virtually all polyurethane foam applications and replaced, in many cases, with the more environmentally acceptable HCFCs, or in some cases in Europe, with hydrocarbons. At the same time, the search continues for zero ozone depletion potential blowing agents and some possible candidates are HFCs, hydrocarbons and water. The physical properties such as boiling point and solubility characteristics of the new blowing agents vary widely and formulations have had to be adapted to new types of blowing agents in order to achieve acceptable processing and resultant foam properties.One of the big limitations to adapting formulations has been the ability of the present test methods to predict performance of foam blown with the new blowing agents. Predictive tests for the dimensional stability of fully CFC-11 blown systems have proven their validity over the years. But such is not the case with foams blown with the new blowing agents. ICI developed a new, more stringent, t...