Stabilization of poly(vinyl chloride). VI. Synergetic effects of aminopolycarboxylates or nitrogen‐containing agents with zinc stearate/calcium stearate soap

Abstract

AbstractDiscoloration such as zinc burning was observed in aged poly(vinyl chloride) (PVC) compounded with synergetic soaps. This discoloration was caused by excessive formation of cool color‐producing π complexes formed between double bonds in polyene chain and zinc chloride or cadmium chloride produced from the corresponding metal soap. The appearance of excessive color of the π complexes was reduced by adding some masking agents into PVC admixed with synergetic soaps. In the present study differences in masking effects results by adding solid or an aqueous solution of aminopoly‐carboxylates such as glycine, ethylenediaminetetraacetates, and nitrilotriacetates to PVC stabilized with zinc stearate/calcium stearate synergetic soap. The mechanism of synergetic effect between nitrogen‐containing agents and synergetic soaps upon the stabilization of PVC is also investigated by colorimetry. The aqueous solution of aminopolycarboxylates exhibits a greater masking effect than the solid. The masking effect of aminopolycarboxylates depends on the ease with which they are fnely dispersed into PVC. Colorimetry indicated that the masking effect of aminopolycarboxylates and other nitrogen‐containing agents depends on forming the colorless complex compound with the excessive cool color‐producing metal chlorides.