To smoothly, steadily and stably obtain the subject polymer useful as a high quality material for medical use and the like by subjecting an aliphatic polyhydric alcohol, an aliphatic polybasic acid, and the like to a dehydrative polycondensation reaction under the control of reaction conditions based on specific measurement data.
This method for producing an aliphatic polyester comprises subjecting an aliphatic polyhydric alcohol and an aliphatic polybasic acid and/or a hydroxycarboxylic acid, or their oligomer or polymer to a thermal dehydrative polycondensation reaction in an organic solvent to obtain the polyester having a weight-average mol.wt. of ≥15,000, while measuring one or more physical properties selected from the number of terminal groups, the content of water, a concentration and the mol.wt. in the reaction mixture with time by the use of a near IR light spectroscopic meter having an analyzer capable of carrying out multivariate analyses by chemometrics and controlling a reaction time and two or more reaction conditions selected from the temperature of a reactor, the pressure of the reactor, the flow of an inactive gas, the content of water, the concentration and a refluxing amount on the basis of the measurement results.
ITOU TOMOMICHI
NAKAJIMA RYOICHI
ICHISE KOICHI
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