Process for producing articles formed from polylactic acid and articles made therefrom

Patent metadata

Field	Value
Publication number	US-9732184-B2
Application number	US-201514811054-A
Country	US
Kind code	B2
Filing date	Jul 28, 2015
Priority date	Jul 29, 2014
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

PLA polymers that can be expanded into microporous articles having a node and fibril microstructure are provided. The fibrils contain PLA polymer chains oriented with the fibril axis. Additionally, the PLA polymers have an inherent viscosity greater than about 3.8 dL/g and a calculated molecular weight greater than about 150,000 g/mol. The PLA polymer article may be formed by bulk polymerization where the PLA bulk polymer is made into a preform that is subsequently expanded at temperatures above the glass transition temperature and below the melting point of the PLA polymer. In an alternate embodiment, a PLA polymer powder is lubricated, the lubricated polymer is subjected to pressure and compression to form a preform, and the preform is expanded to form a microporous article. Both the preform and the microporous article are formed at temperatures above the glass transition temperature and below the melting point of the PLA polymer.

First claim

What is claimed is:

1. A PLA polymer article comprising:
an expanded PLA polymer comprising a detectable beta crystal phase and having nodes and fibrils,
wherein said nodes comprise a volume of said expanded PLA polymer, and
wherein said fibrils originate and terminate from said nodes.

2. The PLA polymer article of claim 1 , wherein said fibrils comprise polymer chains and said polymer chains are oriented along a fibril axis.

3. The PLA polymer article of claim 1 , wherein said expanded PLA polymer comprises at least one comonomer.

4. The PLA polymer article of claim 1 , wherein said expanded PLA polymer comprises poly L-lactic acid (PLLA), poly d-lactic acid (PDLA), poly L-lactide, poly D-lactide, and combinations thereof.

5. The PLA polymer article of claim 1 , wherein said PLA polymer article is formed from a PLA polymer that has a melt enthalpy greater than about 30 J/g.

6. The PLA polymer article of claim 1 , wherein said PLA polymer article is formed from a PLA polymer that has an inherent viscosity greater than about 3.8 dL/g.

7. The PLA polymer article of claim 6 , wherein said PLA polymer has a molecular weight greater than about 150,000 g/mol.

8. The PLA polymer article of claim 6 , wherein said PLA polymer has an inherent viscosity greater than about 5 dL/g.

9. The PLA polymer article of claim 8 , wherein said PLA polymer has a molecular weight greater than about 290000 g/mol.

10. The PLA polymer article of claim 1 , wherein said expanded PLA polymer is microporous.

11. The PLA polymer article of claim 1 , wherein said expanded PLA polymer has a porosity less than about 10%.

12. The PLA polymer article of claim 1 , wherein said expanded PLA polymer has a matrix tensile strength greater than or equal to 110 MPa.

13. The PLA polymer article of claim 1 , wherein said expanded PLA polymer has a matrix modulus greater than or equal to 3000 MPa.

14. The PLA polymer article of claim 1 , wherein said expanded PLA polymer has a porosity greater than about 25%.

15. The PLA polymer article of claim 1 , wherein said PLA polymer article is formed from a PLA polymer comprising at least one member selected from the group consisting of a filler material and a coating material.

16. The PLA polymer article of claim 1 , wherein said article is in the form of a fiber, tube, tape, sheet, or a three dimensional self-supporting structure.

17. An article comprising:
an expanded PLA polymer comprising a detectable beta crystal phase and having nodes and fibrils; and
at least one filler material,
wherein said nodes include a volume of said expanded PLA polymer, and
wherein said fibrils originate and terminate from said nodes.

18. The article of claim 17 , wherein said filler material is selected from the group consisting of inorganic materials, carbon black, aerogels, metals, semi-metals, ceramics, carbon/metal particulate blends, activated carbon, hydrogel materials, bioactive substances, stiffening agents, and combinations thereof.

19. The article of claim 17 , wherein said PLA polymer comprises poly L-lactic acid (PLLA), poly d-lactic acid (PDLA), poly L-lactide, poly D-lactide, and combinations thereof.

20. A PLA polymer article comprising:
an expanded PLA polymer comprising a detectable beta crystal phase and having nodes and fibrils,
wherein said expanded PLA polymer has a porosity less than about 10%.

21. The PLA polymer article of claim 20 , wherein said fibrils comprise polymer chains and said polymer chains are oriented, along a fibril axis.

22. The PLA polymer article of claim 20 , wherein said expanded PLA polymer comprises at least one comonomer.

23. The PLA polymer article of claim 20 , wherein said expanded PLA polymer comprises poly L-lactic acid (PLLA), poly d-lactic acid (PDLA), poly L-lactide, poly D-lactide, and combinations thereof.

24. The PLA polymer article of claim 20 , wherein said expanded PLA polymer is microporous.

25. The PLA polymer article of claim 20 , wherein said expanded PLA polymer has a matrix tensile strength greater than or equal to 110 MPa.

26. The PLA polymer article of claim 20 , wherein said expanded PLA polymer has a matrix modulus greater than or equal to 3000 MPa.

27. The PLA polymer article of claim 20 , wherein said article is in the form of a fiber, tube, tape, sheet, or a three dimensional self-supporting structure.

28. The PLA polymer article of claim 1 , wherein said beta phase is detected by at least one of differential scanning calorimetry (DSC), X-ray diffraction (XRD), and wide angle X-ray diffraction (WAXD).

29. The article of claim 17 , wherein said beta phase is detected by at least one of differential scanning calorimetry (DSC), X-ray diffraction (XRD), and wide angle X-ray diffraction (WAXD).

Assignees

• Gore & Ass

Inventors

• Sbriglia Guy A
• Gore Scott A

Classifications

• B29K2105/04

  cellular or porous · CPC title

• B29C43/32

  Component parts, details or accessories; Auxiliary operations · CPC title

• B29C44/348

  by regulating the temperature and/or the pressure, e.g. suppression of foaming until the pressure is rapidly decreased · CPC title

• C08J9/0066

  Use of inorganic compounding ingredients · CPC title

• B29K2033/04

  Polymers of esters · CPC title