| 摘要 |
PROBLEM There is provided a method for producing polylactic acid, which is capable of obtaining polylactic acid at low cost, and having high molecular weight. SOLUTION A method for producing polylactic acid by polymerizing molten lactide using at least one reactor having plug flow characteristics with &xgr;(τ), calculated from the following FORMULA (1), of 0.3 or smaller: &xgr;(τ)=∫0∞(E(τ)×ABS(1−τ))dτ  (1) in the Formula (1), E(τ) is a residence time distribution function determined by impulse response by starch syrup having a viscosity of 3 Pa·s, and τ is ratio of elapsed time &thetas; and mean residence time &thetas;0. |
