Poly (hydroxyalkanoic acid) compositions with improved toughness, dimensional stability and stretchability

1. A composition comprising about 50 to about 99.5 wt % of a poly(hydroxyalkanoic acid), about 0.1 to about 40 wt % of an ethylene ester copolymer, and about 0.05 to about 5 wt % of an aliphatic carboxylic acid amide, based on the total weight of the composition, wherein the ethylene ester copolymer comprises (a) about 20 to about 95 wt % of copolymerized units of ethylene, (b) about 0.5 to about 25 wt % of copolymerized units of at least one ester of the formula CH 2 ═C(R 1 )CO 2 R 2 , wherein R 1 is hydrogen or an alkyl group having 1-6 carbon atoms, and R 2 is glycidyl, based on the total weight of the ethylene ester copolymer and (c) 0 to about 70 wt % of copolymerized units of at least one ester of the formula CH 2 ═C(R 3 )CO 2 R 4 , wherein R 3 is hydrogen or an alkyl group having 1 to 8 carbon atoms and R 4 is an alkyl group having 1 to 8 carbon atoms, based on the total weight of the ethylene ester copolymer.

2. A composition of claim 1 , wherein the poly(hydroxyalkanoic acid) comprises polymerized units of one or more hydroxyalkanoic acids selected from the group consisting of 6-hydroxyhexanoic acid, 3-hydroxyhexanoic acid, 4-hydroxyhexanoic acid, 3-hydroxyheptanoic acid, glycolic acid, lactic acid, 3-hydroxypropionic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, and 5-hydroxyvaleric acid.

3. A composition of claim 1 , wherein the poly(hydroxyalkanoic acid) is selected from the group consisting of poly(glycolic acids), poly(lactic acids), poly(hydroxybutyric acids), poly(hydroxybutyric acid-hydroxyvaleric acid) copolymers, and poly(glycolic acid-lactic acid) copolymers.

4. A composition of claim 3 , wherein the poly(hydroxyalkanoic acid) is poly(lactic acid).

5. A composition of claim 4 , wherein the poly(lactic acid) is a stereo complex of poly(D-lactic acid) and poly(L-lactic acid).

6. A composition of claim 1 , wherein the ethylene ester copolymer comprises (a) about 40 to about 90 wt % of copolymerized units of ethylene, (b) about 3 to about 20 wt % of copolymerized units of one or more esters of the formula CH 2 ═C(R 1 )CO 2 R 2 , wherein R 1 is hydrogen or an alkyl group having 1-6 carbon atoms, and R 2 is glycidyl and (c) about 3 to about 70 wt % of copolymerized units of one or more esters of the formula CH 2 ═C(R 3 )CO 2 R 4 , wherein R 3 is hydrogen or an alkyl group having 1 to 8 carbon atoms and R 4 is an alkyl group having 1 to 8 carbon atoms, based on the total weight of the ethylene ester copolymer.

7. A composition of claim 6 , wherein the ethylene ester copolymer comprises (a) about 50 to about 80 wt % of copolymerized units of ethylene, (b) about 3 to about 17 wt % of copolymerized units of one or more esters of the formula CH 2 ═C(R 1 )CO 2 R 2 , wherein R 1 is hydrogen or an alkyl group having 1-6 carbon atoms, and R 2 is glycidyl, and (c) about 20 to about 35 wt % of copolymerized units of one or more esters of the formula CH 2 ═C(R 3 )CO 2 R 4 , wherein R 3 is hydrogen or an alkyl group having 1 to 8 carbon atoms and R 4 is an alkyl group having 1 to 8 carbon atoms, based on the total weight of the ethylene ester copolymer.

8. A composition of claim 1 , wherein the ethylene ester copolymer is selected from the group consisting of ethylene/glycidyl methacrylate copolymers, ethylene/butyl acrylate/glycidyl methacrylate terpolymers, and mixtures thereof.

9. A composition of claim 8 , wherein the ethylene ester copolymer is an ethylene/butyl acrylate/glycidyl methacrylate terpolymer.

10. A composition of claim 1 , wherein the aliphatic carboxylic acid amide is an amide of an aliphatic carboxylic acid having 10 to 30 carbon atoms.

11. A composition of claim 10 , wherein the aliphatic carboxylic acid has 16 to 26 carbon atoms.

12. A composition of claim 10 , wherein the aliphatic carboxylic acid amide is selected from the group consisting of aliphatic monocarboxylic acid amides, N-substituted aliphatic monocarboxylic acid amides, aliphatic carboxylic acid bisamides, N-substituted aliphatic carboxylic acid bisamides, and N-substituted ureas and mixtures thereof.

13. A composition of claim 10 , wherein the aliphatic carboxylic acid amide is behenamide.

14. A composition of claim 1 which comprises about 67 to about 99 wt % of the poly(hydroxyalkanoic acid), about 0.5 to about 20 wt % of the ethylene ester copolymer, and about 0.1 to about 3 wt % of the aliphatic carboxylic acid amide, based on the total weight of the composition.

15. A composition of claim 1 which comprises about 89 to about 99 wt % of poly(lactic acid), about 1 to about 10 wt % of ethylene/butyl acrylate/glycidyl methacrylate terpolymer and about 0.25 to about 1 wt % of behenamide, based on the total weight of the composition.

16. A shaped article comprising a composition comprising about 50 to about 99.5 wt % of a poly(hydroxyalkanoic acid), about 0.1 to about 40 wt % of an ethylene ester copolymer, and about 0.05 to about 5 wt % of an aliphatic carboxylic acid amide, based on the total weight of the composition, wherein the ethylene ester copolymer comprises (a) about 20 to about 95 wt % of copolymerized units of ethylene, (b) about 0.5 to about 25 wt % of copolymerized units of at least one ester of the formula CH 2 ═C(R 1 )CO 2 R 2 , wherein R 1 is hydrogen or an alkyl group having 1-6 carbon atoms, and R 2 is glycidyl, based on the total weight of the ethylene ester copolymer and (c) 0 to about 70 wt % of copolymerized units of at least one ester of the formula CH 2 ═C(R 3 )CO 2 R 4 , wherein R 3 is hydrogen or an alkyl group having 1 to 8 carbon atoms and R 4 is an alkyl group having 1 to 8 carbon atoms, based on the total weight of the ethylene ester copolymer.

17. An article of claim 16 , wherein the poly(hydroxyalkanoic acid) is poly(lactic acid).

18. An article of claim 16 , wherein the ethylene ester copolymer is an ethylene/butyl acrylate/glycidyl methacrylate terpolymer.

19. An article of claim 16 , wherein the aliphatic carboxylic acid amide is behenamide.

20. An article of claim 16 , wherein the composition comprises about 89 to about 99 wt % of poly(lactic acid), about 1 to about 10 wt % of ethylene/butyl acrylate/glycidyl methacrylate terpolymer and about 0.25 to about 1 wt % of behenamide, based on the total weight of the composition.

21. A shaped article comprising a composition comprising about 50 to about 99.5 wt % of a poly(hydroxyalkanoic acid), about 0.1 to about 40 wt % of an ethylene ester copolymer, and about 0.05 to about 5 wt % of an aliphatic carboxylic acid amide, based on the total weight of the composition, wherein the ethylene ester copolymer comprises (a) about 20 to about 95 wt % of copolymerized units of ethylene, (b) about 0.5 to about 25 wt % of copolymerized units of at least one ester of the formula CH 2 ═C(R 1 )CO 2 R 2 , wherein R 1 is hydrogen or an alkyl group having 1-6 carbon atoms, and R 2 is glycidyl, based on the total weight of the ethylene ester copolymer and (c) 0 to about 70 wt % of copolymerized units of at least one ester of the formula CH 2 ═C(R 3 )CO 2 R 4 , wherein R 3 is hydrogen or an alkyl group having 1 to 8 carbon atoms and R 4 is an alkyl group having 1 to 8 carbon atoms, based on the total weight of the ethylene ester copolymer, prepared by a process selected from the group consisting of molding processes, extrusion processes, thermoforming processes and mixtures thereof.

22. An article of claim 16 , wherein the article is in the form of a Rapidly Quenched Sheet.

23. A Rapidly Quenched Sheet of claim 22 wherein the Rapidly Quenched Sheet is an oriented Rapidly Quenched Sheet.

24. A Rapidly Quenched Sheet of claim 22 having a thickness of less than 10 mils (0.25 mm).

25. A Rapidly Quenched Sheet of claim 24 that is an oriented Rapidly Quenched Sheet.