POLYMER-BOUND HINDERED AMINE LIGHT STABILIZERS FOR IMPROVED WEATHERABILITY IN MULTIPHASE POLYMER SYSTEMS

Hindered amine light stabilizers (HALS) have been bound to both the rubber and matrix phases of acrylonitrile-EPDM-styrene (AES) terpolymers. The stabilizers were incorporated by reaction of either 4-aminotetramethylpiperidine or 4-aminooxamidetetramethylpiperidine with anhydride functionality incorporated into the EPDM or SAN. This method permits control of the phase location of the stabilizers in multi-phase polymer systems. Thereby the phase most susceptible to degradation can be positively stabilized. The polymers were evaluated via accelerated weathering. These studies show that the primary function of HALS in AES is to inhibit degradation of the EPDM rubber phase. Superior weathering performance results when HALS is both bound to the rubber phase and melt blended into the product.