Multilayer film comprising polylactic acid
View Patent ↗An article comprises a first polylactic acid layer and a second layer directly adjacent the first layer. The second layer comprises any of ethylene/unsaturated ester copolymer, ethylene/alkyl (meth)acrylate/glycidyl (meth)acrylate copolymer, and styrenic block copolymer. The article may be a shrink sleeve.
1. An article comprising:
a first layer comprising polylactic acid;
a second layer directly adjacent the first layer, the second layer comprising ethylene/unsaturated ester copolymer, wherein the unsaturated ester comonomer content of the ethylene/unsaturated ester copolymer is at least about 35 wt. % based on the weight of the second layer.
2. The article of claim 1 wherein the first layer comprises at least about 50 wt. % polylactic acid based on the weight of the first layer.
3. The article of claim 1 wherein the first layer comprises at least about 90 wt. % polylactic acid based on the weight of the first layer.
4. The article of claim 1 wherein the first layer comprises at least about 95 wt. % polylactic acid polylactic acid based on the weight of the first layer.
5. The article of claim 1 wherein the second layer comprises at least about 50 wt. % of ethylene/unsaturated ester copolymer based on the weight of the second layer.
6. The article of claim 1 wherein the second layer comprises at least about 80 wt. % of ethylene/unsaturated ester copolymer based on the weight of the second layer.
7. The article of claim 1 wherein the unsaturated ester comonomer content of the ethylene/unsaturated ester copolymer is at least about 39 wt. % based on the weight of the second layer.
8. The article of claim 1 wherein the unsaturated ester comonomer content of the ethylene/unsaturated ester copolymer is at least about 40 wt. % based on the weight of the second layer.
9. The article of claim 1 wherein the unsaturated ester comonomer content of the ethylene/unsaturated ester copolymer is at least about 43 wt. % based on the weight of the second layer.
10. The article of claim 1 wherein the unsaturated ester comonomer content of the ethylene/unsaturated ester copolymer is at least about 50 wt. % based on the weight of the second layer.
11. The article of claim 1 wherein the unsaturated ester comonomer content of the ethylene/unsaturated ester copolymer is at most about 75 wt. % based on the weight of the second layer.
12. The article of claim 1 wherein the unsaturated ester comonomer content of the ethylene/unsaturated ester copolymer is at most about 70 wt. % based on the weight of the second layer.
13. The article of claim 1 wherein the unsaturated ester comonomer content of the ethylene/unsaturated ester copolymer is at most about 80 wt. % based on the weight of the second layer.
14. The article of claim 1 wherein the ethylene/unsaturated ester copolymer comprises anhydride-modified ethylene/unsaturated ester copolymer.
15. The article of claim 1 wherein:
the ethylene/unsaturated ester copolymer comprises vinyl ester of aliphatic carboxylic acid comonomer having from 4 to 12 carbon atoms; and
the unsaturated ester comonomer content of the ethylene/unsaturated ester copolymer is at least about 39 wt. % based on the weight of the second layer.
16. The article of claim 15 wherein the vinyl ester of aliphatic carboxylic acid comonomer comprises vinyl acetate comonomer.
17. The article of claim 1 wherein:
the ethylene/unsaturated ester copolymer comprises alkyl (meth)acrylate comonomer having from 4 to 12 carbon atoms; and
the unsaturated ester comonomer content of the ethylene/unsaturated ester copolymer is at least about 39 wt. % based on the weight of the second layer.
18. The article of claim 17 wherein the unsaturated ester comprises alkyl (meth)acrylate comonomer having from 4 to 8 carbon atoms.
19. The article of claim 17 wherein the alkyl (meth)acrylate comonomer comprises one or more comonomers selected from one or more of methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, hexyl acrylate, and 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, hexyl methacrylate, and 2-ethylhexyl methacrylate.
20. The article of claim 1 further comprising a third layer comprising less than about 50% polylactic acid by weight of the third layer, wherein the third layer is directly adjacent the second layer.
21. The article of claim 20 wherein the third layer comprises at least about 50% by weight of the third layer of one or more polymers selected from polyolefin, polyester, polystyrene, and polyamide.
22. The article of claim 21 wherein third layer comprises one or more polyolefins selected from polyethylene, polypropylene, propylene/ethylene copolymer, ethylene/cyclic olefin copolymer, and ethylene/vinyl acetate copolymer.
23. The article of claim 20 wherein the article is a multilayer film.
24. The article of claim 23 wherein the first layer is an outer layer of the multilayer film.
25. The article of claim 23 wherein the first layer is an internal layer of the multilayer film.
26. The article of claim 23 wherein the second layer is an internal layer of the multilayer film.
27. The article of claim 23 wherein the third layer is an outer layer of the multilayer film.
28. The article of claim 23 wherein the multilayer film has a free shrink at 100° C. in at least one direction of at least about 10%.
29. The article of claim 28 wherein the total density of the multilayer film is less than about 1 g/cc.
30. The article of claim 28 wherein the total density of the multilayer film is greater than about 1 g/cc.
31. The article of claim 23 wherein the multilayer film has a haze of at most about 30%.
32. The article of claim 20 wherein the article is a sheet.