Patent ID: 8846853

Claim:
A method of polycondensing polylactic acid comprising: a. subjecting a reaction vessel containing an 85-90 mass % aqueous solution of lactic acid to a vacuum and filling the vessel with argon, b. repeating step (a) three times, c. with argon remaining in the vessel, heating to 130-150° C. to dehydrate the lactic acid for 1-6 hours, d. reducing the vessel pressure to 100 Torr to dehydrate at 130-150° C. for 1-6 hours, e. reducing the vessel pressure to 30 Torr to dehydrate at 130-150° C. for 1-6 hours to form n moles of oligomers of lactic acid having 5-8 lactic acid repeat units, f. adding 0.001 n to 0.01 n moles of creatinine to the reaction vessel, and g. reducing the vessel pressure to 10 Torr and heating to 150-190° C. for 48-96 hours to produce the polylactic acid.