Patent ID: 7094862

Claim:
A process for the preparation of a polyester containing several free acid functions arranged in the middle of the chain, based on a member of the group consisting of L-lactic acid, D-lactic acid, DL-lactic acid, ε-caprolactone, p-dioxanone, ε-caproic acid, alkylene oxalate, cycloalkylene oxalate, alkylene succinate, β-hydroxybutyrate, substituted or non-substituted trimethylene carbonate, 1,5-dioxepan-2-one, 1,4-dioxepan-2-one, glycolide, glycolic acid, L-lactide, D-lactide, DL-lactide, meso-lactide; and all optically active isomers, racemates or copolymers of the latter comprising ring-opening polymerization in the presence of as a chain initiator: tartaric acid benzyl diester, the phenyl portion of the benzyl which is optionally substituted.