Flame retardance of organotin compounds in polyurethane

Abstract

This thesis investigated that dibutyltin oxide(DBTO),dibutyltin diacetate(DBTA), and zinc hydroxystannate(ZHS), in combination with chlorinated paraffin wax 70(C70), aliphatic compound containing 70% by weight of chlorine., increased flame retardancy and reduced rate of smoke evolution in rigid polyurethane foam. Limiting Oxygen Index (LOI) results demonstrated that increases in flame resistance are also possible through inclusion of chlorinated paraffin wax in combination with tin compounds function in a synergistic manner. The highest LOI values of these binary system, 3g DBTA/C70,7g DBTO/C70 and 7g ZHS/C70, were greater than that given by Dimethoxymethyl phosphate(DMMP), a commercial fire retardant in foam but were lower than those when DMMP used in combination with C70 or DBDPO. However, the great benefit imparted by these dual additive systems was to reduce the smoke evolution. In view of the lower smoke production of these compounds their possible use as fire retardant additives for rigid polyurethane system should merit serious consideration. Thermal analysis of polyurethane foams suggested that the fire retardant actions of the tin additives appeared to be almost exclusively due to solid phase activity.