THERMAL-CONDUCTIVITY REDUCTION OF POLYURETHANE INSULATING FOAM BY IN-SITU CARBON-DIOXIDE REMOVAL

dPolyurethane foam of the type used for most refrigerator insulation is currently blown in the United States with a mixture of diclorofluoroethane (R-141b), and CO2. The object of this work has been to reduce the thermal conductivity of this foam by passively removing CO, from the cell gas of the foam. This work is applicable to foams blown with R-141b, R-356, cyclopentane, and other low-boiling liquids plus CO2. In work with hand-mixed foams we demonstrated that NaOH in the form of beads or powder is an effective material for in situ CO2 removal from foam. After removal of CO2, originally present at 14%, foam thermal conductivity at refrigerator operating conditions was reduced 9%.