| Abstract: | Two zinc borates are useful partial replacements for the antimony oxide flame retardant normally used to flame retard flexible PVC products. The effect of using various co-additives with zinc borates on the flame retardancy and smoke formation of a model flexible PVC cable jacket was evaluated in an attempt to further improve the properties of the formulation. The use of ammonium octamolybdate with the borates yields products with improved properties. Highly flame retarded formulations that yield low levels of smoke can be prepared by using alumina trihydrate or magnesium compounds as replacements for the usual calcium carbonate filler. Replacement of part of the phthalate ester plasticizer with brominated ester, a phosphate ester, or a brominated phosphate ester also results in formulations with oxygen values as high as 39.5 which produce lower levels of smoke. |
