Synthesis and its thermal stability for poly(vinyl chloride) of antimony tris(mercaptoethyl stearate)

The synthesis of a novel type of thermal stabilizer - antimony tris(mercaptoethyl stearate) is presented. Its thermal stabilities have been measured by heat-ageing oven test when incorporated into PVC. Antimony tris(mercaptoethyl stearate) has been synthesized from stearic acid, antimony trioxide and 2-mercapto ethanol in two steps. The reaction conditions of synthesis have been optimized through orthogonal test. The experimental results show that antimony tris(mercaptoethyl stearate) is synthesized by reacting of stearic acid with antimony tris(2-hydroxyethylmercaptolate) at the mole ratio C17H35 COOH: Sb(SCH3CH2OH)3=3.6, adding 0.4% tetra-n-butyl titanate catalyst and 50% xylene solvent (mass percentage based on the mass of stearic acid), heating and refluxing for about 4 hours. The yield of antimony tris(mercaptoethyl stearate)is 83.9%. The thermal stability time is about 40min(at 200°C) when added 2phr(per hundred resin) in PVC. The thermal stability time of complex stabilizer of antimony tris(mercaptoethyl stearate) and calcium stearate is better than that of Ca-Zn complex and basic lead stabilizers and equal to that of dibutyltin dilaurate.