Thermochemical Behavior of Formulated Polyol Systems Containing Chlorofluorocarbons

Abstract

510Abstracts Both bench and full scale foam evaluations of Y 10591 have confirmed that this new low combustibility surfactant is a superior candidate for the full range of conventional flexible polyurethane slabstock foam formulations. In each case, Y 10591 provided high foam breathability, indicating the wide processing latitude, and minimal back collapse, foam density and density gradients confirming its superior efficiency as a surfactant. These attributes along with its low combustibility performance make Y-10591 an excellent surfactant for the full range of flexible slabstock foams.The blowing agents typically used in polyurethane foam formulations are chlorofluorocarbons (CFCs) such as trichlorofluoromethane (CFC-11) and dichloromethane. Several materials of construction are used in the plants that manufacture flexible and rigid polyurethane foam products. These include mild steel, stainless steel (usually 316 alloy) and less frequently copper or its alloys such as brass. Literature precedent exists for the chemical reduction of chlorofluorocarbons when in contact with these metals, as well as aluminum and galvanized steel (zinc). Evidence for the CFC reduction reaction in the handling and processing of formulated polyol systems may be material color change, loss of system reactivity, or an increase in temperature and/or pressure in storage vessels. This study focused on the behavior of systems in contact with the selected metals in both adiabatic (Accelerated Rate Calorimetry) and isothermal (Polyol Degradation Apparatus) reactors. These tools were used to probe the thermal behavior of various systems and to correlate the influences of the various formulation components and metals on the potentially hazardous CFC reduction reaction. These adiabatic and isothermal laboratory techniques are also used to evaluate storage conditions for systems which may react. These screening techniques have been incorporated into Dow's product development protocol so that future technology improvements not only meet customer specifications, but also satisfy Dow's adiabatic and isothermal aging requirements.