Scavenging oxygen
A closure 40 for a container body includes a liner 46 which incorporates a hydrogen generating device comprising a hydride which generates hydrogen on contact with moisture. The liner may be an interference fit within the body 42 . The liner 46 and other liners described may include control means for controlling passage of moisture to the hydrogen generating means and/or sealing means for sealing the closure to a container. In use, with the closure secured to a container, water vapor passes into liner 46 and contacts the hydride which generates hydrogen. A reaction between hydrogen and oxygen which has passed into the container takes place, catalysed by a catalyst, and water is produced. Thus, oxygen is scavenged.
1. A closure for a container body, the closure comprising a hydrogen generating means which includes an active material arranged to generate molecular hydrogen on reaction with moisture, wherein said hydrogen generating means comprises a matrix material in which said active material is embedded, wherein said hydrogen generating means is in combination with a control means for controlling passage of moisture to the hydrogen generating means, wherein said control means is arranged to control passage of moisture so as to reduce the rate of hydrogen generation by said hydrogen generating means compared to the rate in the absence of said control means, wherein said control means comprises a layer of material having a water vapour permeability of less than 2.0 g.mm/m 2 .day, and wherein said hydrogen generating means is capable of generating hydrogen for a period of time of at least 1 month.
2. A closure as claimed in claim 1 , wherein said control means comprises a plurality of layers which are secured to one another and make face to face contact.
3. A claim according to claim 1 , wherein the rate of passage of moisture through the control means, towards the hydrogen generating means, is slower than the rate of passage of water through said matrix material of said hydrogen generating means.
4. A closure according to claim 1 , wherein the ratio of the permeability in g.mm/m 2 .day of the control means to the water permeability of the matrix material is 1 or less.
5. A closure according to claim 1 , wherein the control means comprises a material which has a water vapour permeability in g.mm/m 2 .day which is less than the water vapour permeability of a polymeric matrix material present in the greatest amount in said matrix material.
6. A closure according to claim 1 , the control means defines the rate determining step for passage of moisture to the active material of the hydrogen generating means.
7. A closure according to claim 1 , wherein said hydrogen generating means has a length of at least 20 mm.
8. A closure according to claim 1 , wherein said matrix material comprises a polymeric matrix material selected from polyolefins, low density polyethylene, high density polyethylene, polypropylene, styrene-ethylene-butylene (SEBS) copolymers, Nylon 6, styrene, styrene-acrylate copolymers and ethylene vinyl acetate.
9. A closure for a container body, the closure comprising a hydrogen generating means which includes an active material arranged to generate molecular hydrogen on reaction with moisture, wherein said hydrogen generating means comprises a matrix material in which said active material is embedded, wherein said hydrogen generating means is in combination with a control means for controlling passage of moisture to the hydrogen generating means, wherein said control means is arranged to control passage of moisture so as to reduce the rate of hydrogen generation by said hydrogen generating means compared to the rate in the absence of said control means, wherein said control means comprises a polymeric material selected from HDPE, PP, LDPE, PET, EVA, SEBS and Nylon, and wherein said hydrogen generating means is capable of generating hydrogen for a period of time of at least 1 month.
10. A closure as claimed in claim 9 , wherein said control means comprises a plurality of layers which are secured to one another and make face to face contact.
11. A closure according to claim 9 , wherein the rate of passage of moisture through the control means, towards the hydrogen generating means, is slower than the rate of passage of water through said matrix material of said hydrogen generating means.
12. A closure according to claim 9 , wherein the ratio of the permeability in g.mm/m 2 .day of the control means to the water permeability of the matrix material is 1 or less.
13. A closure according to claim 9 , wherein the control means comprises a material which has a water vapour permeability in g.mm/m 2 .day which is less than the water vapour permeability of a polymeric matrix material present in the greatest amount in said matrix material.
14. A closure according to claim 9 , wherein the control means defines the rate determining step for passage of moisture to the active material of the hydrogen generating means.
15. A closure according to claim 9 , wherein said hydrogen generating means has a length of at least 20 mm.
16. A closure according to claim 9 , wherein said matrix material comprises a polymeric matrix material selected from polyolefins, low density polyethylene, high density polyethylene, polypropylene, styrene-ethylene-butylene (SEBS) copolymers, Nylon 6, styrene, styrene-acrylate copolymers and ethylene vinyl acetate.
17. A closure for a container body, the closure comprising a hydrogen generating means which includes an active material arranged to generate molecular hydrogen on reaction with moisture, wherein said hydrogen generating means comprises a matrix material in which said active material is embedded, wherein said hydrogen generating means is in combination with a control means for controlling passage of moisture to the hydrogen generating means, wherein said control means is arranged to control passage of moisture so as to reduce the rate of hydrogen generation by said hydrogen generating means compared to the rate in the absence of said control means, wherein said control means comprises a plurality of layers which are secured to one another and make face to face contact, and wherein said hydrogen generating means is capable of generating hydrogen for a period of time of at least 1 month.
18. A closure according to claim 17 , wherein the rate of passage of moisture through the control means, towards the hydrogen generating means, is slower than the rate of passage of water through said matrix material of said hydrogen generating means.
19. A closure according to claim 18 , wherein said matrix material comprises a polymeric matrix material selected from polyolefins, low density polyethylene, high density polyethylene, polypropylene, styrene-ethylene-butylene (SEBS) copolymers, Nylon 6, styrene, styrene-acrylate copolymers and ethylene vinyl acetate.
20. A closure according to claim 17 , wherein the ratio of the permeability in g.mm/m 2 .day of the control means to the water permeability of the matrix material is 1 or less; and said control means defines the rate determining step for passage of moisture to the active material of the hydrogen generating means.