| 摘要 |
<p>A process for producing a polysuccinimide having a weight-average molecular weight of 40,000 or higher, which comprises: the step (1) of mixing and heating aspartic acid and an acid catalyst to produce a liquid low-molecular polymer mixture; the step (2) of moderately separating the acid catalyst from the liquid mixture to directly change the polymer-containing liquid phase to a solid phase and thereby produce a solid low-molecular polymer mixture; and the step (3) of subjecting the resultant solid mixture to solid state polymerization. The process can be conducted with a simple apparatus and is free from problems such as generation of a highly viscous phase, excessive foaming, and reaction product bulking.</p> |
