“Cleaner Blowing Agents” are required to have Zero-Ozone Depletion Potential in Rigid Polyurethanes. The most commonly used Hydrocarbon blowing agent HCFC 141b is being phased out in USA. Newer regulatory norms are expected to be introduced and HCFC 141b will be completely eliminated by January 1, 2005 in the USA. The phase-out date for production of HCFC-22 and HCFC-142b, which have lower ozone-depletion potential, is Jan 1, 2007. The latter two have had limited use in rigid PUR foam, mostly as blends with HCFC-141b.

A newer agent, HFC 245fa, is relatively superior as cost-effective formulation for building and construction, appliances and automotive integral-skin foams. North American appliance makers and laminators have been faster in adopting alternative blowing agents.The main contenders for refrigeration foams are HFC-245fa and HFC-134a, the later in use in Europe along with USA. A majority of appliance makers favor the non-flammable HFC-245fa, as it has been shown to yield the lowest cabinet energy consumption. HFC 245fa is very expensive but very effective in producing rigid foam for refrigerator with good insulation characteristics. However, the advantages of superior physical properties as well as cost of HCFC-141b cannot be matched by any of the alternatives. As compared to HCFC-141b, the HFCs cost approximately 1.5 to 4 times more. Several new developments have been aimed to optimize the level of expensive HFC 245fa to prevent significant cost increase of the formulation. Apparently higher water level along with HFC245fa help in reducing the level. A newly developed blowing agent enhancer also helps in lowering levels of HFC245fa by at least 10-20% level. This new additive reduces the viscosity and thus helps to reduce the level of HFC245fa. Great Lakes is introducing novel flame retardants which can work more effectively with hydrocarbon blowing agents to meet the flammability requirements of the flexible foam products.