Enzymatic depolymerization process of polylactic acid, and producing process of polylactic acid using depolymerization product

• US 7,396,667 B2
• Filed: 07/30/2003
• Issued: 07/08/2008
• Est. Priority Date: 08/05/2002
• Status: Expired due to Fees

• Current Assignee: KEIO University
• Original Assignee: KEIO University
• Inventors: Matsumura, Shuichi
• Primary Examiner(s): Lilling; Herbert J
• Application Number:
  US10/523,688
• Publication Number:
  US 20050233425A1
• Time in Patent Office: 1,805 Days
• Field of Search: 435/135, 435/123, 435/124, 435/125, 435/126, 435/195, 435/196, 435/198
• US Class Current: 435/135
• CPC Class Codes: C08G 63/823 for the preparation of polylactones or polylactides
• CPC Class Codes: C08J 11/105 by treatment with enzymes
• CPC Class Codes: C08J 2367/04 Polyesters derived from hydroxy carboxylic acids, e.g. lactones C08J2367/06 takes precedence
• CPC Class Codes: C12P 7/56 Lactic acid
• CPC Class Codes: C12P 7/62 Carboxylic acid esters
• CPC Class Codes: Y02P 20/54 using solvents, e.g. supercritical solvents or ionic liquids
• CPC Class Codes: Y02W 30/62 Plastics recycling; Rubber recycling

Abstract

A depolymerizing process of polylactic acid, wherein the polylactic acid is depolymerized in the presence of a hydrolase in an organic solvent or a supercritical fluid, thereby producing a re-polymerizable oligomer. A producing process of polylactic acid, wherein the re-polymerizable oligomer obtained by the above-mentioned depolymerization process is polymerized in the presence of a hydrolase or a polymerization catalyst.

Claims

1. A depolymerizing process of polylactic acid, wherein the polylactic acid is depolymerized in the presence of a hydrolase that is a lipase in an organic solvent, thereby producing a re-polymerizable oligomer.

3. The depolymerizing process of polylactic acid according to claim 1, wherein the polylactic acid is poly(L-lactic acid).

5. The depolymerizing process of polylactic acid according to claim 1, wherein the polylactic acid is poly(DL-lactic acid).

7. The depolymerizing process of polylactic acid according to claim 1, wherein the polylactic acid is a polylactic acid copolymer.

2. A depolymerizing process of polylactic acid, wherein the polylactic acid is depolymerized in the presence of a hydrolase in a supercritical fluid, thereby producing a re-polymerizable oligomer.

4. The depolymerizing process of polylactic acid according to claim 2, wherein the polylactic acid is poly(L-lactic acid).

6. The depolymerizing process of polylactic acid according to claim 2, wherein the polylactic acid is poly(DL-lactic acid).

8. The depolymerizing process of polylactic acid according to claim 2, wherein the polylactic acid is a polylactic acid copolymer.

9. The depolymerizing process of polylactic acid according to claim 2, wherein the hydrolase is lipase.