The present invention provides a wall for a package, which wall comprises, or includes a layer comprising, a composition comprising a polymer and capable of scavenging oxygen through the metal-catalysed oxidation of an oxidizable organic component thereof. The oxidizable organic component is preferably itself a polymer, and may be the only polymer in the composition. Preferred compositions include a blend of 96% polyethylene terephthalate and 4% poly (m-xylyleneadipamide) containing 200 ppm cobalt as catalyst, with good permeance-versus-time performance (3) when formed into a bottle.
1. An oxygen-scavenging monolayer container wall comprising an oxygen-scavenging composition, the oxygen-scavenging composition comprising:
a non-oxidizable polyester component;
a polymeric organic oxidizable component; and
a transition metal in the positive oxidation state that promotes the oxidation of the polymeric organic oxidizable component, wherein the monolayer container wall achieves an oxygen permeance of not more than 10.0 cm 3 / 2 atm day, in part as the result of the transition metal in the positive oxidation state promoting the oxidation of the polymeric organic oxidizable component, wherein the polymeric organic oxidizable component is present in the wall in the range of from 1 to 7 weight percent.
2. The monolayer container wall of claim 1 wherein the wall achieves an oxygen permeance of not more than 2.0 cm 3 / 2 atm day, in part as the result of the transition metal in the positive oxidation state promoting the oxidation of the polymeric organic oxidizable component.
3. The monolayer container wall of claim 2 wherein the wall achieves an oxygen permeance of not more than 0.5 cm 3 /m 2 atm day, in part as the result of the transition metal in the positive oxidation state promoting the oxidation of the polymeric organic oxidizable component.
4. The monolayer container wall of any of claims 1 - 3 wherein the non-oxidizable polyester component is polyethylene terephthalate.
5. The monolayer container wall of any of claims 1 - 3 wherein the non-oxidizable polyester component and the polymeric organic oxidizable component are separate polymers.
6. The monolayer container wall of claim 5 wherein the polymeric organic oxidizable component contains units of the formula —NH—CH 2 -arylene-CH 2 —NH—CO-alkylene-CO—.
7. The monolayer container wall of claim 6 wherein the polymeric organic oxidizable component is MXD6.
8. The monolayer container wall of claim 7 wherein the non-oxidizable polyester component is about 96% by weight of the oxygen-scavenging composition.
9. The monolayer container wall of claim 8 wherein the oxidizable component is about 4% by weight of the oxygen-scavenging composition.
10. The monolayer container wall of claim 9 wherein the transition metal is cobalt.
11. An oxygen-scavenging composition comprising:
a non-oxidizable polyester component;
a polymeric organic oxidizable component; and
a transition metal in the positive oxidation state that promotes the oxidation of the polymeric organic oxidizable component that, when incorporated into a monolayer container wall, the monolayer container wall achieves an oxygen permeance of not more than three-quarters of the permeance of the monolayer wall in the absence of oxygen scavenging as a result of the transition metal in the positive oxidation state promoting the oxidation of the polymeric organic oxidizable component.
12. The composition of claim 11 , wherein the oxygen-scavenging composition achieves an oxygen permeance of not more than one-half of the permeance of the monolayer wall in the absence of oxygen scavenging.
13. The composition of any of claims 11 - 12 wherein the non-oxidizable polyester component is polyethylene terephthalate.
14. The composition of any of claims 11 - 12 wherein the non-oxidizable polyester component and the polymeric organic oxidizable component are separate polymers.
15. The composition of claim 14 wherein the polymeric organic oxidizable component contains units of the formula —NH—CH 2 -arylene-CH 2 —NH—CO-alkylene-CO—.
16. The composition of claim 15 wherein the polymeric organic oxidizable component is MXD6.
17. The composition of any of claims 11 - 12 wherein the transition metal component is cobalt.
18. The composition of claim 16 wherein the transition metal is cobalt.