Catalyst – solid sorbent – or support therefor: product or process – Solid sorbent – Having specifically intended extraneously added iron group...
Reexamination Certificate
1998-10-19
2003-12-23
Hendrickson, Stuart L. (Department: 1754)
Catalyst, solid sorbent, or support therefor: product or process
Solid sorbent
Having specifically intended extraneously added iron group...
C252S188280
Reexamination Certificate
active
06667273
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a composition for and a method of absorbing oxygen and releasing carbon dioxide in a container having a product and a high moisture environment from which oxygen was flushed and which contains carbon dioxide and some oxygen.
In certain packaging procedures, a gas flush containing carbon dioxide is utilized to replace oxygen which may have a deteriorating effect on the product within a container. Most gas flushing methods leave between about 0.5% to 2% oxygen in the container. In environments of this type, compositions which absorb oxygen and also generate carbon dioxide are used to absorb oxygen which may have remained in the container or which may leak into the container or which may be generated by the product in the container. It has been found that merely using an oxygen absorber without a carbon dioxide generator does not operate satisfactorily because the oxygen is not absorbed rapidly or sufficiently. For some unexplained reason the generation of carbon dioxide hastens the time and quantity of oxygen absorption. The carbon dioxide which is generated replaces oxygen which is absorbed. However, prior compositions for absorbing oxygen were not stable in that they released carbon dioxide prematurely, that is, before they were placed into their operating environment within the container.
SUMMARY OF THE INVENTION
It is the object of the present invention to provide an improved composition for absorbing oxygen and generating carbon dioxide in a container having a product and high moisture and which has had a flush with a gas containing carbon dioxide and which is extremely stable so that it will not become active to release carbon dioxide prematurely, that is, until it is placed into the container having the high moisture environment.
Another object of the present invention is to provide an improved method for absorbing oxygen and generating carbon dioxide in a container having a product and a high moisture content and which has had a flush with a gas containing carbon dioxide. Other objects and attendant advantages of the present invention will readily be perceived hereafter.
The present invention relates to a composition for absorbing oxygen and releasing carbon dioxide in a high moisture environment comprising by weight an iron-based component in an amount of between about 15% and 60%, a carbon dioxide releasing component in an amount of between about 8% and 50%, an acidifying component, and a dry water-attracting component for attracting moisture from the high moisture environment to thereby activate the iron-based component to absorb oxygen and also activate the acidifying component to combine with said carbon dioxide releasing component to cause it to release carbon dioxide.
The present invention also relates to a method of removing oxygen from a container having a product and a high moisture environment and wherein oxygen was previously flushed out and replaced by a gas containing carbon dioxide and wherein some oxygen may have remained and into which additional oxygen may have entered and which exists as a relatively small percentage of the total volume of the gas containing carbon dioxide and oxygen comprising the steps of providing a container, placing a product into said container, flushing the container with a gas containing carbon dioxide to remove other gases from said container, and providing in said container a mixture of an oxygen-absorbing component, a carbon dioxide generating component, an acidifying component, and a dry water-attracting component for attracting moisture from the high moisture environment to thereby activate said oxygen-absorbing component to absorb said additional oxygen and also activate said acidifying component to combine with said carbon dioxide releasing component to cause it to release carbon dioxide.
The various aspects of the present invention will be more fully perceived from the following portions of the specification.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As noted briefly above, in certain prior packaging applications, after a product has been placed in a container, a flush with a gas containing carbon dioxide is used to replace oxygen which may have a deteriorating effect on the product within the container. This gas may be pure carbon dioxide or a mixture of carbon dioxide and nitrogen. Thereafter, a combined oxygen-absorbing and carbon dioxide generating composition is placed into the container to absorb oxygen which may have remained in the container or which may leak into or be formed in the container. The generated carbon dioxide replaces at least part of the oxygen which is absorbed. However, insofar as known, prior compositions were not stable in that they released carbon dioxide prematurely, that is, before they were placed into their operating environment. In order to overcome the foregoing deficiency, the improved method of the present invention utilizes a composition which adds a dry water-attracting component to the oxygen-absorbing component and the carbon dioxide releasing component. The dry water-attracting component stabilizes the composition against premature activity, that is, before it is placed into its high moisture environment. For some unknown reason, in an environment of the above type, the use of an oxygen absorber by itself without a carbon dioxide generator will not absorb the oxygen as quickly and as fully as when a carbon dioxide generator is also used.
In the practice of the improved method a product is added to a container, and the gases in the container are flushed out with a gas containing carbon dioxide to the extent that the carbon dioxide content of the container is at least 20% with the remaining atmosphere in the container containing less than about 17% oxygen and usually between about 0.5% to 2% oxygen. There-after, as part of the method, the improved composition of the present invention is added for absorbing any oxygen which remains in the container or which leaks into the container or is generatd by the product in the container. The composition is extremely stable in that it will not become active until the moisture within the container is adsorbed by a dry moisture-attracting component of the composition, and thus the composition cannot be activated prematurely. The product in the container may be a food such as meat, fish, coffee, bread and cheese, or any other food product, or any other product which may be deleteriously affected by oxygen.
The oxygen-absorbing component of the improved composition is preferably particulate iron which is blended with powdered sodium chloride, which functions as an electrolyte when it combines with water. The particulate iron may be present in the composition by weight in an amount of between 15% and 60% and preferably between 20% and 40% and most preferably between 25% and 35%. The iron in the presence of an electrolyte will combine with the oxygen from the environment. The particle size of the iron can be between 30 and 635 mesh and preferably between 100 mesh and 375 mesh and most preferably between 200 mesh and 325 mesh. While particulate iron is preferred, other iron based components can be used including but not limited to iron II sulfate, iron II oxide, iron II carbide and iron carbonyl. When pure iron is used it may be of any type. Aluminum, copper, zinc and other oxidizable metals can be used.
The composition includes an electrolyte material. One which is preferred is sodium chloride and it should be in the same range of particulate sizes as discussed above relative to the iron. The sodium chloride may be present in an amount of between about 0% and 3½% and preferably between about 2% and 2½%. Above 3½% no increase in the reaction rate occurs. At 0% sodium chloride, the reaction is slower than if sodium chloride was present because the other salts which exist in the composition, namely, the sodium bicarbonate, will function as an electrolyte, but not as effectively. The exact amount of sodium chloride is not critical, but it is best to have the above prefera
Cullen John S.
McKedy George E.
Gastel Joseph P.
Hendrickson Stuart L.
Multisorb Technologies, Inc.
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