METHOD OF PREPARING POLYALKYLENE CARBONATE RESIN

• US 20170226284A1
• Filed: 12/08/2015
• Published: 08/10/2017
• Est. Priority Date: 12/08/2014
• Status: Active Grant

• Current Assignee: LG Chem Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: LEE, Jin Woo, KIM, Yoon Jung, JUNG, Taek Jun, SOHN, Jung Min, CHO, Yun Ki, AN, Yong Hee, LEE, Jun Wye, PARK, Seung Young
• Granted Patent: US 10,457,773 B2
• Time in Patent Office: Days
• CPC Class Codes: C08G 64/0208 saturated
• CPC Class Codes: C08G 64/34 and cyclic ethers
• CPC Class Codes: C08G 64/40 Post-polymerisation treatment
• CPC Class Codes: C08G 64/406 Purifying; Drying

Abstract

A method of preparing a polyalkylene carbonate resin is provided. More particularly, a method of preparing a polyalkylene carbonate resin capable of preventing polymer degradation and improving physical properties and quality of a final resin product, in which, after polymerization of polyalkylene carbonate, by-products are removed by using a large amount of water to purify a reaction mixture, and in a subsequence process of removing a catalyst residue, a primary purification method is conducted by using a filter so that a content of the catalyst in the reaction mixture is less than 1% by weight, is provided.

Claims

1. A method of preparing a polyalkylene carbonate resin, the method comprising the steps of:

preparing a reaction mixture comprising polyalkylene carbonate, a catalyst residue, unreacted residual monomers, a solvent, and alkylene carbonate-comprising by-products by polymerizing monomers comprising carbon dioxide and an epoxide compound in the presence of the catalyst and the solvent;

recovering residual monomers from the reaction mixture;

removing the by-products from the reaction mixture, from which the residual monomers have been removed, by using 200 parts by weight to 1000 parts by weight of water with respect to 100 parts by weight of the monomers;

removing the catalyst residue from the reaction mixture, from which the residual monomers and the by-products have been removed, by using a filter having a pore size of less than 50 um; and

removing the solvent from the reaction mixture, from which the residual monomers and the catalyst residue have been removed.

2. The method of preparing the polyalkylene carbonate resin of claim 1, wherein the step of removing the by-products is conducted by using water after packing the reaction mixture in a rotating disc contactor-type extraction column.

3. The method of preparing the polyalkylene carbonate resin of claim 1, wherein the step of recovering the residual monomers is conducted by a method of removing carbon dioxide by venting and removing the epoxide compound by distillation.

4. The method of preparing the polyalkylene carbonate resin of claim 1, wherein a pore size of the filter is less than 20 um.

5. The method of preparing the polyalkylene carbonate resin of claim 1, wherein a pore size of the filter is 1 um to 10 um.

6. The method of preparing the polyalkylene carbonate resin of claim 1, wherein the step of removing the catalyst residue is conducted by passing the reaction mixture through the filter so that a content of the catalyst is less than 1% by weight.

7. The method of preparing the polyalkylene carbonate resin of claim 1, wherein the step of removing the catalyst residue further comprises the step of successively using an ion exchange resin after using the filter.

8. The method of preparing the polyalkylene carbonate resin of claim 7, comprising the step of removing the catalyst residue by primarily removing the catalyst residue from the reaction mixture, from which the residual monomers and the by-products have been removed, through the filter, and then by secondarily removing the catalyst residue from the reaction mixture by using the ion exchange resin so that a content of the catalyst is 300 ppm or less based on the total weight of the reaction mixture.

9. The method of preparing the polyalkylene carbonate resin of claim 1, further comprising the step of purifying the monomers, prior to the polymerization step.

10. The method of preparing the polyalkylene carbonate resin of claim 1, wherein the step of removing the solvent is conducted by using a combination of one or more instruments selected from the group consisting of a simple flash drum, a falling film evaporator, a thin film evaporator, an extrusion DV, and a filmtruder.

11. The method of preparing the polyalkylene carbonate resin of claim 1, wherein the catalyst is a zinc-based catalyst, and the by-products comprise an alkylene carbonate having 1 to 5 carbon atoms.

12. The method of preparing the polyalkylene carbonate resin of claim 1, wherein the epoxide compound is one or more selected from the group consisting of:

an alkylene oxide having 2 to 20 carbon atoms substituted or unsubstituted with a halogen or an alkyl group having 1 to 5 carbon atoms;

a cycloalkylene oxide having 4 to 20 carbon atoms substituted or unsubstituted with a halogen or an alkyl group having 1 to 5 carbon atoms; and

a styrene oxide having 8 to 20 carbon atoms substituted or unsubstituted with a halogen or an alkyl group having 1 to 5 carbon atoms, and

the solvent is methylene chloride or ethylene dichloride.