Photodegradable polyesters

A process for the preparation of a polyester comprising repeating unit (A) and comprising less than 0.5 mole % repeating unit (B) based on the total number of moles of diacids or diesters, wherein

• repeating unit (A) is ##STR11## and repeating unit (B) is:
• ##STR12## wherein R.sup.1 is selected from the group consisting of hydrogen, alkyl having 1 to 6 carbon atoms and aryl having 6 to 10 carbons and R.sup.2 is selected from the group consisting of hydrogen, alkyl having 1 to 6 carbon atoms, and aryl having 6 to 10 carbon atoms which comprises the steps of:
• (1) reacting a 4-substituted-benzaldehyde(s) having the formula:
• ##STR13## with a ketone having the formula:
• ##STR14## in the presence of an acidic or basic condensation catalyst to obtain an intermediate compound having the formula:
• ##STR15## (2) hydrogenating the intermediate compound in the presence of a catalytic amount of a hydrogenation catalyst selected from mixed copper-chromium oxides and supported Group VIII nobel metals under hydrogenation conditions of pressure and temperature;
• wherein for structure ##STR16## R.sup.1 is selected from the group consisting of hydrogen, alkyl having 1 to 6 carbon atoms and aryl having 6 to 10 carbon atoms and R.sup.2 is selected from the group consisting of hydrogen, alkyl having 1 to 6 carbon atoms, and aryl having 6 to 10 carbon atoms, and R.sup.3 and R.sup.4 are selected from the group consisting of hydrogen and alkyl having 1 to 6 carbon atoms;
• and
• (3) polymerization of the ketone-containing diester or diacid and a diol or diols and, optionally, with other diesters or diacids at temperatures of 200.degree.-300.degree. C. and pressures of 1000 mm to 0.01 mm.