ALIPHATIC POLYESTER MANUFACTURING METHOD

• US 20110306733A1
• Filed: 02/17/2010
• Published: 12/15/2011
• Est. Priority Date: 02/23/2009
• Status: Active Grant

• Current Assignee: Kureha Corporation
• Original Assignee: Kureha Corporation
• Inventors: Suzuki, Yoshinori, Watanabe, Takahiro, Sato, Hiroyuki, Maeda, Fumio
• Granted Patent: US 8,691,912 B2
• Time in Patent Office: Days
• US Class Current: 525/415
• CPC Class Codes: B01J 19/006 Baffles
• CPC Class Codes: B01J 19/0066 Stirrers mixing per se B01F
• CPC Class Codes: B01J 19/18 Stationary reactors having moving elements inside B01J19/08, B01J19/26 take precedence
• CPC Class Codes: B01J 19/1862 placed in series
• CPC Class Codes: B01J 19/20 in the form of helices, e.g. screw reactors
• CPC Class Codes: B01J 2219/00094 Jackets
• CPC Class Codes: B01J 2219/00779 Baffles attached to the stirring means
• CPC Class Codes: B01J 2219/182 horizontal
• CPC Class Codes: B01J 2219/185 vertical
• CPC Class Codes: B01J 2219/1943 cylindrical
• CPC Class Codes: B01J 2219/1946 conical
• CPC Class Codes: B29C 48/03 characterised by the shape of the extruded material at extrusion
• CPC Class Codes: B29C 48/287 Raw material pre-treatment while feeding B29C48/78 takes precedence
• CPC Class Codes: B29C 48/288 in solid form, e.g. powder or granules
• CPC Class Codes: B29C 48/385 using two or more serially arranged screws in separate barrels
• CPC Class Codes: B29C 48/39 a first extruder feeding the melt into an intermediate location of a second extruder
• CPC Class Codes: C08G 63/06 derived from hydroxycarboxylic acids
• CPC Class Codes: C08G 63/785 characterised by the apparatus used
• CPC Class Codes: C08G 63/80 Solid-state polycondensation

Abstract

A process for producing an aliphatic polyester, comprising: subjecting at least two serial stages of bulk-phase ring-opening polymerization and a solid-phase polymerization step, wherein a cyclic ester held in a dry air atmosphere is supplied to a first reactor to perform a first stage polymerization, thereby obtaining a partially polymerized molten product, and the resultant partially polymerized molten product is supplied to a second reactor held under a dry inert gas atmosphere to perform a second stage polymerization. As a result, the production efficiency can be improved, while maintaining excellent properties of the aliphatic polyester product.

Claims

1. A process for producing an aliphatic polyester, comprising:

subjecting at least two serial stages of bulk-phase ring-opening polymerization, and a solid-phase polymerization step, wherein a cyclic ester held in a dry air atmosphere is supplied to a first reactor to perform a first stage polymerization, thereby obtaining a partially polymerized molten product; and

the resultant partially polymerized molten product is supplied to a second reactor held under a dry inert gas atmosphere to perform a second stage polymerization.

2. A production process according to claim 1, wherein the cyclic ester melted in a dry air atmosphere is supplied to the first reactor, thereby performing the first stage polymerization.

3. A production process according to claim 1, wherein the first reactor is a fully filled-type biaxial stirring reactor.

4. A production process according to claim 1, wherein the second stage polymerization is performed in the second reactor of which a connection part with the first reactor is held in a dry inert gas atmosphere.

5. A production process according to claim 1, wherein the dry inert gas is dry nitrogen.

6. A production process according to claim 1, wherein the cyclic ester is glycolide.

7. A production process according to claim 6, wherein the glycolide is a product obtained by depolymerization of glycolic acid oligomer according to a solution-phase depolymerization method.

8. A production process according to claim 1, wherein a catalyst melted in a low boiling solvent vaporizable at the first stage polymerization temperature is added to the cyclic ester prior to supply thereof to the first reactor.

9. A production process according to claim 8, wherein an initiator is added to the cyclic ester simultaneously with or prior to the catalyst.

10. A production process according to claim 1, wherein a partially polymerized molten product from the second reactor is solidified, crushed and then subjected to the solid-phase polymerization step.

11. A production process according to claim 10, wherein the partially polymerized product after the solidification and crushing is pelletized together with a thermal stabilizer and then subjected to the solid-phase polymerization step.