| abstract |
UV stable linear polyesters, e. g. PET, contain in their chain copolymerised bis(hydroxyalkoxy)xanth-9-ones, preferably 3,8-bis-(2-hydroxyethoxy)xanth-9-ones. The polymers are obtained by polymerisation in the presence of a tetrahydroxy benzophenone, preferably the 2,2',4,4'-isomer. The method of polymerising in the presence of dihydric phenols to obtain ethoxyaryloxy polyesters is also described. |