Polypropylene and polylactic acid formulations for heat seal applications

Patent metadata

Field	Value
Publication number	US-9290650-B2
Application number	US-201414220997-A
Country	US
Kind code	B2
Filing date	Mar 20, 2014
Priority date	Jun 30, 2008
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

Films (or a cap layer of co-extruded films) and methods of forming the same are described herein. The films generally include a modified olefin based polymer including polypropylene and from 1 wt. % to 30 wt. % polylactic acid (PLA), wherein the modified olefin based polymer exhibits a seal initiation temperature (SIT) that is at least 5° C. less than a seal initiation temperature of the polypropylene absent the PLA and a hot tack range of at least 20° C.

First claim

What is claimed is:

1. A film or a cap layer of co-extruded films comprising:
a modified olefin based polymer comprising polypropylene, a reactive modifier comprising a functionalized polyolefin, and from 1 wt. % to 30 wt. % polylactic acid (PLA);
wherein the reactive modifier is formed by grafting in the presence of an initiator and a modifier, wherein the modifier comprises polyethylene glycol diacrylate, trimethylolpropane triacrylate, alkloxylated hexanediol diacrylate, or trimethylolpropane triacrylate esters.

2. The film or cap layer of co-extruded films of claim 1 , wherein the film or cap layer of co-extruded films exhibits a seal initiation temperature that is less than 125° C.

3. The film or cap layer of co-extruded films of claim 1 , wherein the polypropylene is a metallocene catalyzed polypropylene.

4. The film or cap layer of co-extruded films of claim 1 , wherein the polypropylene is a Ziegler-Natta catalyzed polypropylene.

5. The film or cap layer of co-extruded films of claim 1 , wherein the film or cap layer of co-extruded films exhibits a hot tack range between 80° C. and 120° C.

6. The film or cap layer of co-extruded films of claim 1 , wherein the modified olefin based polymer comprises from 5 wt. % to 20 wt. % of the PLA.

7. The film or cap layer of co-extruded films of claim 1 , wherein the PLA is amorphous, crystalline or a combination thereof.

8. The film or cap layer of co-extruded films of claim 1 , wherein the modified olefin based polymer comprises from 1-10% of the reactive modifier.

9. The film or cap layer of co-extruded films of claim 1 , wherein the functionalized polyolefin comprises the epoxy-functionalized polypropylene.

10. The film or cap layer of co-extruded films of claim 1 , wherein the modifier further comprises styrene.

11. The film or cap layer of co-extruded films of claim 1 , wherein the modifier comprises polyethylene glycol diacrylate or alkloxylated hexanediol diacrylate.

12. A method of forming a film comprising:
providing a modified olefin based polymer comprising polypropylene, a reactive modifier comprising a functionalized polyolefin, and from 1 wt. % to 30 wt. % polylactic acid (PLA), wherein the reactive modifier is formed by grafting in the presence of an initiator and a modifier, wherein the modifier comprises polyethylene glycol diacrylate, trimethylolpropane triacrylate, alkloxylated hexanediol diacrylate, or trimethylolpropane triacrylate esters; and
forming the modified olefin based polymer into a film.

13. The method of claim 12 , wherein the polypropylene is a metallocene catalyzed polypropylene.

14. The method of claim 12 , wherein the polypropylene is a Ziegler-Natta catalyzed polypropylene.

15. The method of claim 12 , wherein the film exhibits a seal initiation temperature that is less than 125° C.

16. The method of claim 12 , wherein the film exhibits a hot tack range between 80° C. and 120° C.

17. The method of claim 12 , wherein the modified olefin based polymer comprises from 5 wt. % to 20 wt. % of the PLA.

18. The method of claim 12 , wherein the modified olefin based polymer comprises from 1-10% of the reactive modifier.

19. The method of claim 12 , wherein the functionalized polyolefin comprises the epoxy-functionalized polypropylene.

20. The method of claim 12 , wherein the modifier further comprises styrene.

21. The method of claim 12 , wherein the modifier comprises polyethylene glycol diacrylate or alkloxylated hexanediol diacrylate.

Assignees

• Fina Technology

Inventors

• Li Fengkui
• Ashbaugh John

Classifications

• C08J5/18 Primary

  Manufacture of films or sheets · CPC title

• C08L23/26 Primary

  modified by chemical after-treatment (saponified copolymers C08L23/0861; unsaturated acid salts C08L23/0876) · CPC title

• C08L51/06

  grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond · CPC title

• C08L23/0884

  Epoxide-containing esters · CPC title

• C08L51/003

  grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds (C08L51/04, C08L51/06 take precedence) · CPC title