Process for producing dicyclopentadienyl-modified polyester compositions

A process for preparing a polyester composition comprising the steps of:

• (a) contacting a molar excess of an alpha, beta unsaturated dicarboxylic acid or derivative thereof with an organic polyol for a time and at a temperature sufficient to form a composition comprising a carboxylic acid terminated polyester having the formula:
• ##STR12## wherein n is a number having an average value of about 2 to less than about 4, m is a number equal to the free valence of R less the average value of n, the ratio of n to m is greater than about 2.0, and R is the residuum of a polyester which contained from 2 to 4 inclusive hydroxyl groups;
• and
• (b) contacting a Diels-Alder adduct of cyclopentadiene with an olefinic or acetylenic hydrocarbon or alkylated derivative thereof with the carboxylic acid terminated polyester of (a) in the presence of a non-oxidizing acid catalyst having a non-nucleophilic anion for a time and at a temperature sufficient to form a composition comprising an unsaturated ester having the formula:
• ##STR13## wherein n, m and R are as defined above and R.sub.1 is the residuum of a Diels-Alder adduct of cyclopentadiene with an olefinic or acetylenic hydrocarbon or alkylated derivative thereof having from 2 to about 20 carbon atoms.