CLEANING OF BATCHWISE POLYCONDENSATION REACTION TANK

摘要

PROBLEM TO BE SOLVED: To perfectly remove polylactic acid remaining at a narrow part without taking out respective attached parts. ;SOLUTION: The reaction tank main body 1 of a batchwise polycondensation reaction tank E after the completion of previous batchwise treatment is filled with a solvent 10 having a b.p. higher than the m.p. of polylactic acid. Thereafter, the solvent 10 is heated by allowing a heating medium with a predetermined temp. to flow to a heat transfer coil 6 and/or a jacket 2 or a heating means such as a separately prepared heater to be held to a temp. higher than the m.p. of polylactic acid but lower than the b.p. of the solvent for a predetermined time and, thereafter, an opening and closing valve 3 is opened to discharge the solvent 10 having residual polylactic acid 8 dissolved therein.;COPYRIGHT: (C)1998,JPO