New high performance phosphites

Phosphorous based derivatives (phosphites and phosphonites) are well known to be effective as polymer stabilisers mainly during processing, acting as secondary antioxidants and are particularly effective in combination with phenols (primary antioxidants). In addition some phosphites and phosphonites can help in improving the discoloration of polymer articles when they are exposed to heat, UV light, nitrogen oxides (gas fading) and to gamma rays. However, phosphorous based stabilisers are sensitive to heat and moisture so they can cause undesired side problems during processing and in the life time of polymer articles making useless their benefits. The aim of this study is to test a new phosphite compound more hydrolytically stable than the commercial ones and to present its outstanding performances in improving discolouration during processing as well as when polymer articles are exposed to gamma rays. The comparison has been carried out with standard available products. (C) 2001 Elsevier Science Ltd. All rights reserved.