Article comprising polylactic acid layers and process of making the same

Patent metadata

Field	Value
Publication number	US-9833969-B2
Application number	US-201314439080-A
Country	US
Kind code	B2
Filing date	Oct 29, 2013
Priority date	Oct 30, 2012
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

The invention concerns an article comprising layers of polylactic acid and a process of making the same. A layer is of foamed polylactic acid. A layer preferably comprises an impact modifier. The article can be used in the field of packaging.

First claim

The invention claimed is:

1. An article comprising a multilayer plastic material comprising:
A) at least one layer A of a non-foamed polylactic acid material A comprising polylactic acid and an impact modifier,
B) at least one layer B of a foamed polylactic acid material B comprising polylactic acid and being substantially free of: (i) expanded microspheres and (ii) impact modifier.

2. The article according to claim 1 , wherein the material B contains at least one adduct of a chemical foaming agent.

3. The article according to claim 2 , wherein the chemical foaming agent comprises at least one of citric acid or sodium bicarbonate.

4. The article according to claim 2 , wherein the adduct is at least one of sodium citrate, cis-aconitic acid, trans-aconitic acid, cis-aconitic anhydride, trans-aconitic anhydride, itaconic anhydride and citraconic anhydride, or a mixture thereof.

5. The article according to claim 1 , wherein the material B has a density of from 0.5 to 1.2 g/cm 3 .

6. The article according to claim 1 , having a density of from 0.75 to 1.2 g/cm 3 .

7. The article according to claim 1 , wherein the impact modifier is a core/shell polymeric compound, an alkyl sulfonate compound, Acetyl TriButyl citrate, Triethyl citrate, Polybutylene Succinate, PVA or ethylene vinyl acetate.

8. The article according to claim 1 , wherein the material A comprises from 0.01% to 30% by weight of the impact modifier.

9. The article according to claim 1 , comprising at least 19% by weight of the at least one layer B.

10. The article according to claim 1 , wherein the article is a three-layer material (first layer A)-(layer B)-(second layer A).

11. The article according to claim 10 , wherein amounts of the layers by distance along an article thickness correspond to the following profile:
the first layer A: from 5 to 45%,
the layer B: from 10 to 90%,
the second layer A: from 5 to 45%,

the total being 100% of the article thickness.

12. The article according to claim 1 , wherein the article is a plastic sheet.

13. The article according to claim 12 , wherein the plastic sheet has a thickness of from 0.5 mm to 2 mm.

14. The article according to claim 1 , wherein the article is a container.

15. The article according to claim 14 , wherein the container is a thermoformed article.

16. The article according to claim 14 , wherein the article is selected from the group consisting of a bottle and a thermoformed cup.

17. A process of making an article according to claim 1 , comprising a step of mixing polylactic acid and a chemical foaming agent to form a mixture, and a step of heating the mixture to generate a gas compound from the chemical foaming agent.

18. The process according to claim 17 , wherein the chemical foaming agent is at least one of citric acid or sodium bicarbonate, and wherein the gas compound comprises CO 2 .

19. The process according to claim 17 , wherein heating is performed at a temperature of from 150 to 250° C.

20. The process according to claim 17 , wherein heating is performed during an extrusion step to form the at least one layer B.

21. The process according to claim 17 , wherein the at least one layer A and the at least one layer B are co-extruded.

22. The process according to claim 17 , wherein the article is a thermoformed container obtained by:
1) co-extruding the at least one layer A and the at least one layer B to obtain a multilayer plastic sheet, and
2) thermoforming the plastic sheet to obtain the thermoformed container.

Assignees

• Gervais Danone Sa
• Clariant Int Ltd

Inventors

• Chivrac Frédéric
• Jacob Anne-Flore
• Wegner Jan-Eric
• Groeseling Mirco

Classifications

• B32B27/065

  of foam · CPC title

• B32B2307/738

  Thermoformability · CPC title

• B32B2250/24

  All layers being polymeric · CPC title

• B32B27/36

  comprising polyesters · CPC title

• B32B2266/0264

  Polyester · CPC title