Stabilising polyalkylene terephthalate moulding compsns. - using neutral esters op phosphorous acid contg. oxetane gps.

摘要

Poly(alkylene terephthalate) moulding materials are stabilised by a neutral ester (I) of phosphorous acid having >=1 oxetane gp. Pref. the polymer is polyethylene terephthalate of intrinsic viscosity 0.6-0.9 or polybutylene terephthalate of intrinsic viscosity 0.6-1.5 (esp. 0.75-1.3), and (I) is present at a level of 0.0013-0.0168 wt. % (as phosphorus) based on the compsn. A pref. cpd., (I) has formula (Ia):- (I) provides the polyester with improved resistance to heat-induced colour and mol. wt. degradation during melt processing.