A Novel Additive Concept for the Stabilization of ABS
The grafted rubber phase of emulsion ABS has to be stabilised very efficiently against oxidation by hindered phenols, alone or in combination with secondary antioxidants (e.g. phosphites or thioethers), especially during the drying process. Traditionally, solid products with high melting points were used, but they are not easy to bring into an aqueous formulation. A new liquid antioxidant, besides giving excellent thermal stability to the ABS graft phase, can be dosed with a low margin of error and easily emulsified. Such an emulsion shows very good storage stability, and mixes well with the aqueous ABS latex. The liquid supply form brings evident handling advantages, and the product has a very good toxicological profile, as well as broad food contact approvals in styrenic copolymers. To reduce the initial colour of ABS after processing (extrusion, moulding), new synergistic process stabilisers, based on lactone chemistry, have been developed. These new stabilization concepts for ABS graft phase, and ABS compounds help to improve their technical performance significantly. Presented at the 2nd International Conference on Polymer Modification, Degradation and Stabilization, 30 June - 4 July, 2002, Budapest, Hungary, and at the ADDCON World 2002 Conference, 22-23 October 2002, Budapest, Hungary.