Polymeric UV-Absorbers of 2-Hydroxybenzophenone Type. I. Polyesters on the Base of 2-Hydroxy-4-(2,3-epoxypropoxy)benzophenone

Some polyester light stabilizers were synthetized by the co-polymerization of an equimolar mixture of 2-hydroxy-4-(2,3-epoxypropoxy)benzophenone with cyclic anhydrides of di-carboxylic acids. This synthesis was carried out in melt by using potassium benzoate or tert-amines as catalysts. The catalytic efficiency of potassium benzoate in heterogeneous phase increases with its surface area. In comparison with potassium benzoate, tert-amines show a higher catalytic effect in homogeneous medium. According to the UV spectra of the products, the 2-hydroxybenzophenone structural units of light stabilizers are not subject to destruction during the polymerization of an equimolar mixture of epoxide with anhydrides. The efficiency of UV stabilization of the stabilizers prepared in polypropylene is comparable with the efficiency of 2-hydroxy-4-n-octyloxybenzophenone with the exception of those samples which contain the structural units of maleinic anhydride and glycidyl-β-naphthyi ether. In contrast to 2-hydroxy-4-n-octyloxybenzophenone, the high molecular weight UV absorbers exhibit a lower extractibility from polypropylene sheets with trichloroethylene.