Abstract
For the time being, it is indisputable that the prime blowing agent for rigid polyurethane foams is HCFC-141b. Nevertheless, this transitional substance is already subject to growing political pressure which will lead to restriction of its use early in the 21st century.
Additional efforts are needed to identify zero-ODP blowing agents. Solvay has undertaken a thorough screening of 1,1,2-trifluoroethane (HFC-143), a compound which probably represents the best compromise among zero-ODP fluorocarbons for blowing rigid PUR foams. In this contribution we present evidence for the environmental acceptability of HFC-143, and we discuss its suitability as a PUR blowing agent; in both cases advantages over other possible alternatives are stressed.
Results more specifically pertinent to rigid polyurethane foam blowing indicate that under given conditions and for a given formulation, HFC-143 can be processed much more easily than HFC-134a. In this regard, whilst HFC-134a requires a completely new technology, HFC-143 can be considered to be a practically drop-in substitute for HCFC-22/HCFC-142b blends.
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