Patent ID: 11859049
Assignee: LG CHEM, LTD.
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC C | IPC C

Claim 0:
1. A method for preparing a polyalkylene carbonate comprising the steps of:
polymerizing a monomer containing an epoxide compound and carbon dioxide in a solvent in the presence of an organic zinc catalyst to provide a first mixture containing a polyalkylene carbonate, an unreacted epoxide compound, an unreacted carbon dioxide, a residual catalyst, a by-product and a solvent;
removing the unreacted carbon dioxide and the residual catalyst from the first mixture;
removing the unreacted epoxide compound from the first mixture from which the unreacted carbon dioxide and the residual catalyst are removed by using a stripper to provide a second mixture containing the polyalkylene carbonate, the by-product, and the solvent;
heat-exchanging the second mixture;
heating the heat-exchanged second mixture; and
removing the solvent and the by-product from the heated second mixture,
wherein the step of removing the unreacted epoxide compound comprises charging carbon dioxide into the stripper as a stripping agent.