Abstract
The laminated panel industry in both the United States and Europe has successfully converted from chlorofluorocarbons (CFC) to alternative blowing agents. The U.S. markets championed HCFC-141b, while the European markets concentrated on pentane. Since the production and use of HCFCs will be phased out worldwide by the year 2020, all alternative non-chlorinated blowing agents with zero ozone depletion potential (ODP) and low global warming potential (GWP) need to be evaluated to determine which blowing agent candidates are best suited for the different rigid foam applications. It is crucial for researchers in this field to develop products which meet these stringent criteria to ensure the continued growth of the polyurethane rigid foam industry.
Our current emphasis focuses on HFC-245fa and the normal, iso-, and cycloisomers of pentane. As was experienced with the conversion from CFC-11 to HCFC 141b, there are many potential technical challenges associated with blowing agent conversion. These challenges need to be explored by experimentation to ensure a smooth transition into the next generation of blowing agents. At the 1995 and 1996 SPI conferences, work from handmix and full-scale panel evaluations, respectively, was presented which compared properties of foams processed with HFC-245fa to those processed with HCFC-141b. The next phase of our evaluation is to compare foams processed with HFC-245fa to those processed with normal, iso-, and cyclo-pentanes. This paper details a comparative study of these blowing agents in polyisocyanurate and polyurethane rigid-foam systems which currently use HCFC-141b. Full-scale panels were processed on a pilot-scale laminator and were tested for end-use properties.
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