Evaluations of HCFC-123 and HCFC-141b as Potential Blowing Agents for Polyurethane/Polyisocyanurate Rigid Foam Laminate Insulation

Abstract

Trichlorofluoromethane, commonly called CFC-11, is the primary blowing agent used in the production of polyurethane (PUR) or polyisocyanurate (PIR) rigid foams for laminate insulation. CFC-11 is also a member of a class of chlo rofluorocarbons called "hard CFC's," which are believed to contribute to the destruc tion of the earth's protective ozone layer located in the stratosphere above the Antarc tic. Two possible CFC-11 replacements for rigid laminate insulation production with lower ozone depletion potentials than CFC-11 have been identified. They are CF3CHCL2 (HCFC-123) and CCL2FCH3 (HCFH-141b). Many properties of the foam contribute to the overall effectiveness of the laminated insulation product when applied as part of a roof or in a sheathing application Some of these properties in clude foam density, compressive strength, dimensional stability, thermal conductiv ity, and performance in specified flammability tests (ASTM-E84 or UL-723). In order to be a viable replacement for CFC-11, utilizing current laminate chemistry and processing technology, HCFC-123 or HCFC-141b must produce foams that give equivalent or better values than CFC-11 blown foams for the properties listed above. Continuous laminate production evaluations of HCFC-123 abd HCFC-141b were conducted at the North Haven Laboratories of The Dow Chemical Company in a typical rigid laminate formulation to determine the viability of these chemicals as replacement blowing agents of CFC-11. These evaluations included a control run of 100% CFC-11 and blends of HCFC-123 or HCFC-141b with CFC-11. Analyses include reactivity profiles, physical property measurements, initial and aged thermal conductivities, and flammability performance as measured by the UL-723 Tunnel Test.