Hi, During my polyurethane production once the exotherm is peaking and I want to slow the reaction down I add xylene, but not enough to severely effect the temperature. (IE 200 grams in 10000, wont be enough to drop temperature heaps) If I add in slow amounts it works to control the reaction heat. Is there a competing reaction that is causing this? Standard Polyol with Diisocyanate reaction in presence of epoxy catalyst. Any ideas? It works great but just want to understand!