Method of producing glycolic acid polymers

Patent metadata

Field	Value
Publication number	US-10227446-B2
Application number	US-201515521308-A
Country	US
Kind code	B2
Filing date	Nov 6, 2015
Priority date	Nov 6, 2014
Publication date	Mar 12, 2019
Grant date	Mar 12, 2019

Abstract

Described herein is a feasible, significantly simplified production method that avoids challenging lactonization steps and converts a low molecular weight aliphatic polyester, consisting of hydroxy acids and a comonomer, whose molecular weight has been increased by step-growth polymerization reactions. The molecular weight of the aliphatic polyester, based on comparison of initial and final weight average molecular weights (Mw,1/Mw,2), increased significantly at a rate which permits the use of reactive extrusion to produce high molecular weight aliphatic polyesters in a simple, economically feasible manner.

First claim

The invention claimed is:

1. Method of producing a telechelic polymer of glycolic acid, comprising the steps of:
providing glycolic acid;
providing a difunctional monomer;
subjecting said glycolic acid to polymerization in the molten state in the presence of a catalyst and said difunctional monomer;
continuing polymerization in the solid state at 200° C. or less for a prolonged period under reduced pressure to provide a polymeric chain formed by residues derived from glycolic acid and said difunctional monomer,

wherein the catalyst is an organic sulphonic acid having a boiling point in excess of 250° C.

2. The method according to claim 1 , wherein a hydroxyl-terminated polymer chain is formed by the steps of:
providing glycolic acid;
providing a hydroxy-terminated monomer;
subjecting said glycolic acid to condensation polymerization in the molten state in the presence of an esterification catalyst and said hydroxy-terminated monomer;
continuously removing water formed during condensation polymerization; and
continuing polymerization in the solid state at 200° C. or less for a prolonged period under reduced pressure to provide a polymeric chain formed by residues derived from glycolic acid and said hydroxy-terminated monomer,

wherein the catalyst is an organic sulphonic acid having a boiling point in excess of 250° C.

3. The method according to claim 1 , wherein condensation polymerization, in combination with a dehydration step, is continued until a polymer comprising least 5 residues of glycolic acid is obtained.

4. The method according to claim 1 , further comprising preparing glycolic acid homo- or copolymers.

5. The method according to claim 1 , wherein the yield of the polymer is more than 90%.

6. The method according to claim 1 , further comprising preparing glycolic acid homopolymer exhibiting a molecular weight above 30,000 g/mol.

7. The method according to claim 1 , wherein condensation polymerization is carried out in the presence of a catalyst selected from the group of organic sulphonic acid compounds having a boiling point of more than 350° C.

8. The method according to claim 1 , wherein condensation polymerization is carried out in the presence of a catalyst selected from the group of organic sulphonic acid compounds, which have at least one organic residue with at least 10 carbon atoms.

9. The method according to claim 1 , wherein condensation polymerization is carried out in the presence of a catalyst selected from the group of organic sulphonic acid compounds, which have at least one organic residue with an alicyclic residue comprising 1 to 3 alicyclic rings, optionally carrying one or more substituents, comprising camphor sulphonic acid and derivatives thereof.

10. The method according to claim 1 , wherein condensation polymerization is carried out in the presence of lactic acid.

11. The method according to claim 1 , wherein polymerization is continued to provide an essentially linear hydroxy-terminated polymeric chain.

12. The method according to claim 1 , wherein polymerization is continued to provide an essentially branched hydroxy-terminated polymeric chain.

13. The method according to claim 1 , wherein polymerization is carried out in a solvent.

14. The method according to claim 1 , further comprising producing a polymer, having a molecular weight (Mn) of about 20,000 to 1,000,000 g/mol.

15. The method according to claim 1 , wherein the polymerization is carried out in the presence of a sulphonic acid catalyst first in melt stage and the in bulk stage to yield a linear polymer having a molecular weight (Mn) in excess of 20,000 g/mol.

16. The method according to claim 1 , wherein the polymer obtained is subjected to polymerization in the presence of a chain extender to provide a linear polymer having a molecular weight (Mn) of 20,000 to 1,000,000 g/mol.

17. The method according to claim 16 , wherein the chain extenders are selected from the group of diepoxides and diisocyanates.

18. A telechelic homo- or copolymer of glycolic acid produced by a method of producing a telechelic polymer of glycolic acid, the method comprising the steps of:
providing glycolic acid;
providing a difunctional monomer;
subjecting said glycolic acid to polymerization in the presence of a catalyst and said difunctional monomer; and
continuing polymerization to provide a polymeric chain formed by residues derived from glycolic acid and said monomer,

wherein the catalyst is an organic sulphonic acid having a boiling point in excess of 250° C.

19. A telechelic homo- or copolymer of glycolic acid exhibiting a glass transition point in excess of 37° C., and a decomposition temperature, T d 10% of at least 295° C., and having a molecular weight (Mn) of 30,000 to 1,000,000 g/mol.

Assignees

• Teknologian Tutkimuskeskus Vtt Oy

Inventors

• Nurmi Leena
• Gädda Thomas

Classifications

• C08G18/4283

  Hydroxycarboxylic acid or ester · CPC title

• C08G63/81

  using solvents (C08G63/79 takes precedence) · CPC title

• C08G63/87

  Non-metals or inter-compounds thereof (boron C08G63/84) · CPC title

• C08G63/80

  Solid-state polycondensation · CPC title

• C08G63/912

  derived from hydroxycarboxylic acids · CPC title