Quantification of lactide amounts in a polymeric matrix

• US 10,578,549 B2
• Filed: 06/07/2013
• Issued: 03/03/2020
• Est. Priority Date: 06/11/2012
• Status: Active Grant

• Current Assignee: Purac Biochem BV (Corbion NV)
• Original Assignee: Purac Biochem BV (Corbion NV)
• Inventors: Gobius Du Sart, Gerrit, De Jong, Vincent, Niessen, Jan Arie
• Primary Examiner(s): Porta, David P
• Assistant Examiner(s): Malevic, Djura
• Application Number:
  US14/406,638
• Publication Number:
  US 20150168295A1
• Time in Patent Office: 2,461 Days
• Field of Search: 25033907
• CPC Class Codes: C08G 63/08 Lactones or lactides
• CPC Class Codes: C08L 67/04 Polyesters derived from hydroxycarboxylic acids, e.g. lactones C08L67/06 takes precedence
• CPC Class Codes: G01N 2021/8411 Application to online plant, process monitoring
• CPC Class Codes: G01N 2021/8416 and process controlling, not otherwise provided for
• CPC Class Codes: G01N 21/3563 for analysing solids; Preparation of samples therefor
• CPC Class Codes: G01N 21/3577 for analysing liquids, e.g. polluted water
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 2201/061 Sources
• CPC Class Codes: G01N 2201/0826 Fibre array at source, distributing

Abstract

The present invention relates to a method for quantification of the amount of lactide in a lactide-based polymeric matrix by means of Infra Red Spectroscopy measurement. According to the invention the quantification is based on measurements performed on absorptions in the near Infra Red region of the electromagnetic spectrum. The invented method allows a rapid, easy and cheap quantification of lactide in a polymeric matrix, especially in PLA.

Claims

1. Method comprising quantification of the amount of lactide, which is a cyclic dimer of lactic acid, in a lactide-based polymeric matrix by means of Infra Red Spectroscopy measurements,

wherein the amount of lactide is measured in a reaction mixture in which said lactide is polymerized into said lactide based polymeric matrix, which polymeric matrix comprises polylactic acid (PLA) or PLA-containing copolymers,

wherein the quantification is based on measurements performed on absorption spectra recorded by a spectrometer comprising at least one probe disposed in the reaction mixture and operated in the range between 12000 cm⁻

1 and 4000 cm<sup>−

1</sup> in the near Infra Red region of the electromagnetic spectrum so as to capture molecular overtones and combination vibrations of said lactide, and

wherein said quantification of the amount of lactide further includes converting said measurements performed on said absorption spectra using a calculation model that is validated by the use of recorded near Infra Red spectra of mixtures having known amounts of lactide in PLA.

2. Method according to claim 1, wherein the polymeric matrix comprises PLA.

3. Method according to claim 2, wherein the polymeric matrix essentially consists of PLA.

4. Method according to claim 2, wherein the PLA has a M_n of at least 10.000 kg/mol.

5. Method according to claim 1, wherein the amount of lactide is measured in the final polymerization product of the polymeric matrix.

6. Method according to claim 1, wherein the polymerization process is a batch process.

7. Method according to claim 1, wherein the polymerization process is a continuous process.

8. Method according to claim 7 wherein the amount of lactide is measured simultaneously at different stages of the polymerization process.