Scavenging oxygen
View Patent ↗A closure ( 40 ) for a container incorporates calcium hydride and a matrix material as a hydrogen-generating composition. In use, hydrogen is generated which reacts with oxygen permeating a container associated with the closure and a catalyst associated with the container catalyses reaction of the hydrogen and oxygen to produce water, thereby scavenging the oxygen. The composition of calcium hydride and matrix is also claimed.
1. A hydrogen-generating composition comprising calcium hydride associated with a matrix material, wherein the ratio defined as the sum of the wt % of the matrix material divided by the wt % of calcium hydride is at least 2, said calcium hydride makes up at least 50 wt % of total active substances in said hydrogen-generating composition which are arranged to release molecular hydrogen as a result of contact with water, and the total amount of said active substances in said composition which are arranged to release molecular hydrogen is more than 16 wt %.
2. A composition according to claim 1 , wherein said calcium hydride is dispersed in said matrix material and said matrix material has a water vapour permeability of greater than 0.2 g·mm/m 2 ·day.
3. A composition according to claim 2 , wherein said matrix material comprises a thermoplastic polymeric material and said matrix material has a water vapour permeability of less than 5 g·mm/m 2 ·day.
4. A composition according to claim 1 , wherein said calcium hydride comprises a powder with a median particle size from about 0.5 μm to 500 μm.
5. A composition according to claim 1 , which includes more than 16 wt % of calcium hydride.
6. A composition according to claim 1 , which includes 16.5-40 wt % of calcium hydride.
7. A composition according to claim 1 , which includes at least 60 wt % of organic polymers.
8. A composition according to claim 1 , which includes 16.5-30 wt % of calcium hydride and 70-83.5 wt % of matrix material.
9. A composition according to claim 1 , which is in the form of pellets or granules or is in sheet form.
10. A method of making a composition according to claim 1 , the method comprising contacting calcium hydride and matrix material.
11. A method according to claim 10 , wherein calcium hydride is pre-dispersed into a carrier medium prior to mixing with the matrix material.
12. A method according to claim 10 , which comprises extruding or moulding the composition into a shape which can be incorporated into a packaging container.
13. A package containing a hydrogen-generating composition according to claim 1 , wherein the package is arranged to restrict passage of moisture to the calcium hydride in the composition.
14. A container comprising a hydrogen-generating composition comprising calcium hydride associated with a matrix material, wherein said container contains a product which generates head space aldehyde-based flavor components; wherein in said hydrogen-generating composition the ratio defined as the sum of the wt % of the matrix material divided by the wt % of calcium hydride is at least 2, said calcium hydride makes up at least 50 wt % of total active substances in said hydrogen-generating composition which are arranged to release molecular hydrogen as a result of contact with water, and the total amount of said active substances in said composition which are arranged to release molecular hydrogen is more than 16 wt %.
15. A container according to claim 14 , wherein said hydrogen-generating composition is associated with a closure of the container.
16. A container according to claim 14 which includes a control means for controlling passage of moisture to the hydrogen-generating composition, wherein said control means is arranged to control passage of moisture so as to reduce the rate of hydrogen generation by said hydrogen-generating composition compared to the rate in the absence of said control means.
17. A container according to claim 16 , wherein said control means comprises a layer of material having a water vapour permeability of less than 2.0 g·m/m 2 ·day.
18. A closure for a container, said closure comprising a hydrogen-generating composition according to claim 1 .
19. A composition according to claim 3 , wherein said composition includes from 16.5 to 40 wt % active substances which are arranged to release molecular hydrogen on contact with water.
20. A composition according to claim 19 , wherein the sum of the amounts of matrix material and active substances which are arranged to release molecular hydrogen on contact with water is at least 85 wt %.