Method for producing aliphatic polyester, aliphatic polyester resin, and aliphatic polyester resin composition

Patent metadata

Field	Value
Publication number	US-2023151143-A1
Application number	US-202117916900-A
Country	US
Kind code	A1
Filing date	Mar 31, 2021
Priority date	Apr 6, 2020
Publication date	May 18, 2023
Grant date	—

Abstract

An object of the present disclosure is to provide a method for producing an aliphatic polyester resin which substantially does not contain impurities, such as metals, and which has high molecular weight, particularly a polylactic acid having high molecular weight and high optical purity. The method for producing an aliphatic polyester resin of the present disclosure has a step of contacting a solution containing a cyclic ester with a cyclic amine catalyst and a polymerization initiator to initiate a reaction, a step of conducting the reaction by flow-type polymerization, and a step of subjecting the product obtained in the flow-type polymerization to further reaction by postpolymerization by stirring.

First claim

1 . A method for producing an aliphatic polyester, comprising a step of contacting a solution containing a cyclic ester with a cyclic amine catalyst and a polymerization initiator and lowering the temperature from room temperature to initiate a reaction, a step of conducting the reaction by flow-type polymerization, and a step of subjecting the product obtained in the flow-type polymerization to further reaction by postpolymerization by stirring.

2 . The method according to claim 1 , wherein the reaction temperature for the flow-type polymerization is 5° C. or lower, and the reaction temperature for the postpolymerization is 5° C. or lower.

3 . The method according to claim 1 , wherein the postpolymerization by stirring is batch polymerization.

4 . The method according to claim 1 , wherein the product obtained in the flow-type polymerization has a polymer conversion of 45 to 90%.

5 . The method according to claim 1 , wherein the cyclic ester is L-lactide or D-lactide.

6 . An aliphatic polyester resin which does not contain a metal component selected from the group consisting of tin, titanium, aluminum, zinc, zirconium, and antimony, and has a weight average molecular weight of 500,000 or more and an enthalpy of 15.0 J/g or less, based on cooling crystallization made when conducting DSC measurement under the following measurement conditions:
measurement conditions: that, using a differential scanning calorimeter, a sample is heated from room temperature to 200° C. at 10° C./minute, and then cooled to 20° C. at 5° C./minute or 2° C./minute.

7 . The aliphatic polyester resin according to claim 6 , which is a polylactic acid.

8 . The aliphatic polyester resin according to claim 6 , which has an optical purity of 95% or more.

9 . An aliphatic polyester resin composition comprising an aliphatic polyester resin which does not contain a metal component selected from the group consisting of tin, titanium, aluminum, zinc, zirconium, and antimony, and has a weight average molecular weight of 500,000 or more and an enthalpy of 15.0 J/g or less, based on cooling crystallization made when conducting DSC measurement under the following measurement conditions:
measurement conditions: that, using a differential scanning calorimeter, a sample is heated from room temperature to 200° C. at 10° C./minute, and then cooled to 20° C. at 5° C./minute or 2° C./minute.

10 . The aliphatic polyester resin composition according to claim 9 , wherein the aliphatic polyester resin is a polylactic acid.

11 . The aliphatic polyester resin composition according to claim 9 , which has an optical purity of 95% or more.

12 . The aliphatic polyester resin composition according to claim 9 , which has a lactide content of 4,500 ppm or less.

13 . The aliphatic polyester resin composition according to claim 9 , wherein the polylactic acid resin composition obtained after subjected to heat-melting in a nitrogen atmosphere at 200° C. for 30 minutes has a lactide content of 4,000 ppm or less.

14 . A formed article comprising the aliphatic polyester resin composition according to claim 9 .

15 . A medical material comprising the aliphatic polyester resin composition according to claim 9 .

16 . The method according to claim 2 , wherein the postpolymerization by stirring is batch polymerization.

17 . The aliphatic polyester resin according to claim 7 , which has an optical purity of 95% or more.

18 . The aliphatic polyester resin composition according to claim 10 , which has an optical purity of 95% or more.

Assignees

• Teijin Ltd

Inventors

• Masuda Takaya
• Miyamoto Masanori

Classifications

• C08G63/823 Primary

  for the preparation of polylactones or polylactides · CPC title

• C08L2203/02

  for biomedical use · CPC title

• C08G63/08 Primary

  Lactones or lactides · CPC title

• C08L67/04

  Polyesters derived from hydroxycarboxylic acids, e.g. lactones (C08L67/06 takes precedence) · CPC title

• C08G2261/418

  Ring opening metathesis polymerisation [ROMP] · CPC title