BYK P 9909 is a twin amphiphilic polymeric emulsifier that prevents phase separation of polyol blends in storage tanks. BYK P 9909 promotes the compatibility of polyol blends that have a tendency to phase separate and are used to produce special foams. The additive stabilizes the emulsion and therefore facilitates the handling of polyol blends. The reactive mixture and the final product are more homogenous. The easier and faster handling results in lower processing cost with better process control. Costs for packaging and complaint handling are also reduced. BYK P 9909 increases process reliability and reduces application time on site.