The Use of An All CO 2 Blown Foam in Production

Abstract

Prior to the Montreal Protocol on ozone depleting substances, dichlorofluoromethane (CFC-11) had been widely used in polyurethane foam formulations as both a blowing agent and to endow the foam with excellent insulation properties. Now, U.S. manufacturers of products containing rigid polyurethane foam insulation must face the challenge of eliminating CFC-11 from their products. This must be done while retaining the excellent insulation properties that have made PUR foam the most effective insulation material in use today.

Elimination of CFC-11 without any reduction in foam insulation efficiency can be achieved with novel foam systems now in commercial use. These foam systems use C02 as a replacement for CFC-11, but otherwise they are equivalent to CFC-11 based foams in all other respects. Insulated vending equipment is being produced with foam using all C02 blowing and the foam performance is equivalent to, and in some respects better than, the CFC-based foam it replaced. The vending machines have been tested for dimensional stability and energy consumption and initial measurements indicate that the new C02 blown foam gives the same results as CFC-based foams.

Of particular concern to manufacturers is the processability of all C02 blown insulation foams. An experimental design was used to evaluate the processing latitude of variables such as chemical temperatures, mixing pressures, and fixture and preheat temperatures. The effect of varying these process variables on foam performance is reviewed. Particularly how these process variables affect demould time, adhesion, overall physical properties and insulation value.