ABSTRACT
Most rigid foam manufacturers have started their research in preparation for the January 1, 2003 phase-out of most HCPC blowing agents, including HCFC 141b. Manufacturers and development labs alike are currently being challenged with tight conversion schedules and aggressive performance targets. Part of the conversion process is the optimization of basic formulations to achieve the best available physical properties and manufacturing efficiencies. Multiple polyols, surfactants, catalyst systems and blowing agent(s) are typically screened as part of the optimization process.
Hydrocarbons are the blowing agents of choice for many applications because of their balance of reasonable k-factor performance, high blowing efficiency and favorable economics. A variety of hydrocarbon blends are available for Exxon, as well as other suppliers. KoSa has introduced new Ter ate® polyester polyols, designed to maximize the performance of hydrocarbon-blown polyisocyanurate foam formulations.
A survey of available Exxsol® blowing agents and Terate pentane polyols is presented along with formulations, flammability data, and physical testing results from laboratory and machine trials. Suggested starting formulations are presented and discussed for polyisocyanurate “boardstock” and “bunstock” applications. The thermal conductivity, dimensional stability, and flammability properties for the resulting foams are presented and compared to those of conventional HCFC 14 lb-blown foams. Results for a selection of other alternate blowing agents are also presented and discussed.
