Optimization of nontoxic stabilizers for rigid PVC profile

Abstract

Ca- and Zn-stearate were used as stabilizers in rigid PVC profiles instead of Pb-stabilizer to avoid harmful effects to humans of the Pb-stabilizer. This work was carried out in two places. First, the ratios of Ca-stearate, Zn-stearate and the co-stabilizer were adjusted in order to obtain good heat stability. Second, the amounts of the lubricants were adjusted in order to obtain good processing property and surface appearance. The optimum ratio of Ca- to Zn-stearate is 4:1 with addition of 5.0 phr. of epoxidizied soybean oil, 0.5 phr of stearoylbenzoylmethane, tris(nonylphenyl)phosphite and Mg/Al hydroxide carbonate. The optimum amount of lubricants is 0.5 phr. of dicarboxylic acid ester, fatty acid ester, acrylic polymer and 1.0 phr. of polyethylene wax.