Patent Application
20150004287
None.
Not applicable.
1. Field of the Invention
The invention primarily relates to the absorption of carbon dioxide and oxygen from a package containing a food product that emits carbon dioxide and is degraded by oxygen.
2. Description of Related Art
In the packaging of foods, it is known that some food deteriorates by reacting with oxygen during the time it is stored. This has been addressed by evacuating packages to reduce and/or remove oxygen before sealing, by coating foods with wax to protect them from oxygen in the package, and by lowering the temperature of storage to reduce the rate of spoilage. It is also known to utilize oxygen scavengers in the packaging of vegetable and animal based food material. There has been a particular interest in the preventing of oxidation of ground coffee as oxidation decreases the aroma and taste of the product. Freshly roasted coffee emits significant quantities of carbon dioxide for a few days after roasting that, if not accommodated, can cause swelling of the package. Coffee has been vacuum-packed or packed in nitrogen to remove as much oxygen as possible at the time of packaging and to allow space for carbon dioxide.
Certain other foods and manufactured goods in addition to being degraded by absorbing oxygen also emit CO2 either through respiration, baking, or roasting. Coffee, roasted nuts, cheese and certain electrical products produce a significant amount of carbon dioxide. Roasted coffee producers must let coffee off-gas carbon dioxide prior to packaging or include a vent so that the package will not swell and/or burst. The time that is necessary to off-gas carbon dioxide also potentially allows volatile flavor compounds to escape. Employing a carbon dioxide scavenger will allow coffee to be packaged soon after roasting without accumulation of carbon dioxide gas. This lack of staging/exposure for off-gassing will not only eliminate this economically negative processing time but will also consequently result in retaining co-off gassing compounds/volatiles that by their nature impart desirable characteristics of the organoleptic profile of the coffee product.
There is also a problem with carbon dioxide swelling bags of other food products, such as cheese that are also degraded by exposure to oxygen. Some cheeses that include live cultures, blue cheese being one example, benefit from the reduction of oxygen, but not to zero. Some oxygen must be retained to prevent the cultures in the cheese from dying.
Additionally, instant coffee and instant tea are quite aromatic and pleasantly so. Because these desirable flavor aromatics are volatile, any time lost between formation and packaging diminishes flavor and consumer acceptance. A method of adsorbing CO2 from within the package would allow instant coffee, instant tea, and other foods to be packaged soon after roasting and preserve aroma and flavor.
In addition to ground coffee and leaf tea where residue of used coffee grounds and tea leaves are present, there are substantially soluble materials to make hot and cold drinks that present similar storage difficulties, that is, they are degraded by oxygen and emit carbon dioxide. Instant tea, instant juices, and instant coffee may lose flavor and aroma as well as be subject to water absorption which will cause clumping or solidification of the material. Other hot drinks such as cocoa, grain beverages, and hot cold remedy beverages also suffer from storage difficulties. It would be desirable if these materials could be stored in such a way as to prevent their caking or agglomeration. Further, it would be desirable if such materials could be stored in single use containers with protection from clumping and maintaining flavor and aroma while being ready for instant conversion to a beverage.
There is a need to provide oxygen removal, carbon dioxide removal system, and desiccant system which is relatively inexpensive and which is sufficiently potent to remove oxygen, carbon, and water vapor from instant and soluble beverage components.
In particular, there is a need for improvement in storage techniques for single use instant beverage containers. The single use containers are not always subject to good inventory control and therefore may sit on shelves for a long period of time. Further, it is not economical to package single use containers in sophisticated, very low oxygen, water vapor, or nitrogen atmosphere. Typically, single use containers have about 3-5% oxygen by weight in the atmosphere of the container and a varying content of water vapor during packaging and shipping.
There is need for more rapid absorption of carbon dioxide in order to prevent package swelling and flavor loss.
Many oxygen absorbers, particularly those based on transition metals such as iron, require moisture to effectively absorb oxygen. Iron is a particularly effective oxygen absorber, but an electrolyte is needed for the absorption to proceed rapidly. Coating iron particles with salt produces a particle that can begin absorbing oxygen rapidly when water or moisture is added.
The invention provides a method of absorbing carbon dioxide and oxygen comprising providing a package containing a product that gives off carbon dioxide, placing a carbon dioxide absorber that emits water such as calcium hydroxide and an oxygen absorber that is promoted by the water into the package, and sealing the package to form a sealed package.
Oxygen absorbers of the type with which this invention is concerned require water to react with the oxygen. Typically, oxygen absorbers have either been packaged with a source of water in the container, or have been packaged in a container that permits water vapor to enter the package. Neither of these approaches is ideal for products such as coffee that benefit from a dry storage environment. Also, it is desirable for the oxygen absorber to be present in the container, but to be dormant until the food product is introduced. By using water created by absorbing CO2, both of these problems are addressed.
In
The invention has numerous advantages over prior practices in the art. The invention allows the formation of packaging systems where the active component effectively maintains the freshness of the food or medical product. The invention allows the formation of single serving containers with an extended shelf life, while not changing the function or design of the containers. Further, the containers of the invention are low in cost, and the containers of the invention further may utilize biodegradable materials for the absorber and the container. The absorber may be provided in a form that is particularly desirable for different food containers depending on their need for oxygen scavenging, carbon dioxide scavenging, and/or moisture absorbing. These and other embodiments of the invention will be apparent from the detailed description and drawings below.
The phrase “mammal ingestible” is intended to include humans, pets such as dogs and cats, and farm animals. The container of the invention could contain snack drinks, medicine, and food products for non-human mammals. The non-human mammals could ingest the same or different materials as the humans. While this disclosure relates to packages that are especially useful for mammal ingested food, any food or other product that emits carbon dioxide and is degraded by oxygen can benefit from the absorber described herein.
The phrase “human ingestible material” is intended to include, among other things, food, such as instant soup, instant coffee, instant fruit and vegetable juices, and instant tea; and medical products that may be drank or ingested after being withdrawn from the container of the invention. While water is the liquid normally used to dissolve or suspend the human ingestible materials, other liquids compatible with humans, such as juice or plasma, also could be used. Further, a flavored water or water enhanced with mineral or vitamins could be used. The term “sorbent” or “absorber” is used to indicate a material that absorbs carbon dioxide, oxygen, or water vapor by physical or chemical means.
The formation of single serving ready-to-brew coffee that is stored in cups with lidding films is very successful. The containers used in single serve ready to brew coffee are complex. They contain a filter that holds the tea or coffee which is brewed by water passing through the top of the container and out of the bottom of the container. It is desirable to form containers that fit the thousands of ready to brew single use coffee machines currently being used for formation of other hot drinks. Costs could be lowered if the filter was eliminated. Many other hot drinks could be formed from the containers at low cost if the filter was not utilized in the container. However, as the injection of water and extraction of water in these machines is relatively rapid the materials stored in the single use containers must be capable of being rapidly dissolved or dispersed in the brief time the water is in the cup. Therefore, the materials need to maintain their particulate character and not form agglomerates, clumps, or cakes that will not be readily dispersed or dissolved. The invention provides for container with an absorber for materials that would have a deleterious effect on the particular nature of materials in the cup without a filter. Generally, many mammal indigestible materials and human digestible materials will clump, cake, or agglomerate by the action of water vapor. The absorption of these gases in the container would also generally help preserve the flavor and aroma of human indigestible materials dispensed utilizing the container. The taste is more consistent and the shelf life is longer.
The invention provides a cost-effective solution that does not require redesign of the ready-to-brew containers. Coffee machines are designed to accept cups of known design and it is not practical to change the design of the cup. Further, it is desirable that biodegradable materials be utilized as the cups are discarded after one use. The human ingestible materials that do not need to be steeped in a filter include material such as instant coffee, instant tea, fruit and vegetable juices, cold remedies, bullion, chicken broth, some narcotics, and cocoa. These materials may leave the container either as a solution or a dispersion in the hot water.
The washer-shaped absorbent may be made with the techniques described below. The washer and other shaped composite polymer and absorber articles below also may be formed by the technique of U.S. Pat. No. 7,595,278 to Powers, hereby incorporated by reference. Note, Examples 3 and 4 of U.S. Pat. No. 7,595,278 disclose a moisture-absorbing composite material containing propylene and molecular sieve material.
Alternatively or additionally, the sachet may contain a CO2 absorber capable of absorbing the CO2 emitted from the instant coffee or instant tea thereby minimizing loss of flavor through volatilization. It is also possible that a carbon dioxide absorbing sachet could be used in addition to the oxygen absorbing sachet. Water absorbing material could be in a sachet either alone or in addition to the other absorbers.
Alternatively or additionally, the sachet may contain a moisture regulating formulation capable of maintaining the water activity of the instant coffee, cocoa, or other food product such as instant tea, at an optimum level so that it is not too dry or too moist which can affect the extractability of the flavor elements.
In a preferred form for rapid carbon dioxide absorption the sachet, or other container for carbon dioxide absorbing material, will contain a carbon dioxide absorber, such as calcium hydroxide in combination with silica gel. The sachet may also include an oxygen scavenger/absorber, such as iron and/or any of the other oxygen scavenging materials described herein. Alternatively and/or addition, the oxygen scavenger may be disposed in an additional sachet separate from the sachet containing the carbon dioxide absorber. At least a portion of the wall of the sachet or other container is permeable to carbon dioxide. It has been found that calcium hydroxide absorbs carbon dioxide much faster than the conventionally used calcium oxide. Calcium oxide will be hydrolized to form calcium hydroxide which will absorb carbon dioxide. However the delay in acquiring water and reacting with water to form calcium hydroxide is avoided if the carbon dioxide absorber is initially charged with calcium hydroxide. The calcium hydroxide is granular form. In a preferred form the package contains between 38 and 66% by weight of calcium hydroxide when it is combined with silica gel. In the preferred ratio about 100 cm3 of carbon dioxide is absorbed per gram of the calcium hydroxide and silica gel blend. The ratio of silica gel to calcium hydroxide will be maintained even if oxygen absorbers and or water absorbers are also present in the container.
A suitable particle size of calcium hydroxide is between 0.5 and 100 microns. A preferred particle size of calcium hydroxide is about 1-20 microns as this has low-cost and will provide good flowability for manufacturing. The grain size of the silica gel is selected to provide the desired good dry flow characteristics when combined with the calcium hydroxide. Generally a silica gel size of between 0.5 and 100 microns is preferred because of good full flow when mixed with the calcium hydroxide. In such embodiments, a water vapor absorber, such as disodium oxide, calcium oxide, silica gel, molecular sieve, and/or other moisture absorbent materials described herein absorbs water which is a product of the absorption of the carbon dioxide by the calcium hydroxide. Alternatively, as will be described in greater detail below, the water produced by the carbon dioxide absorber as a result of the absorption of carbon dioxide at least partially promotes the oxygen scavenger Calcium hydroxide is less expensive than the calcium oxide which has been used in the prior art. The handling of calcium hydroxide grains is also similar to the handling of the previous calcium oxide. Therefore, the use of calcium hydroxide provides the benefit of faster carbon dioxide absorption activity without increasing cost of the product.
While described as utilized with in sachet such as illustrated in
The sachets, ribbons or containers containing calcium hydroxide for carbon absorption may be shipped in source supply containers. The source supply containers further contain an inner ceiling bag of substantially air and carbon dioxide impermeable polymer sheet. Depending on the type of manufacturing utilizing the calcium hydroxide carbon absorbers they may be in the form of sachets, ribbons, or containers having at least one permeable side. Further the sachets may be linked together in a role and severed immediately prior to use.
Accordingly, an example method of absorbing carbon dioxide using one or more of the sachets 24 and/or containers 10 described herein may include disposing a carbon dioxide absorber and an oxygen scavenger within a container 10 containing a material M or other like product. The product may be disposed within, for example, an inner cavity of the container, and such an inner cavity may be a substantially empty space, compartment, or other like portion of the container 10 configured to receive the product. For example, the inner cavity may comprise a substantially empty space formed by (i.e., substantially surrounded by) the bottom 16 and sidewall 14 of the container 10. In embodiments in which the container 10 is substantially cylindrical, the inner cavity may comprise a substantially cylindrical space within the container 10 extending upward from the bottom 16 to the lid 12, and bound by the sidewall 14. In other embodiments, however, the inner cavity may have other configurations as defined by the sidewall 14, the bottom 16, and/or the lid 12.
The product may comprise any of the mammal ingestible materials, human ingestible materials, and/or other products described herein. In such embodiments, the product may give off, for example, carbon dioxide as is known with ground coffee, or other like products. Additionally, the product may be degradable in the presence of oxygen. Thus, it may be advantageous to reduce and/or substantially eliminate the amount of oxygen within the container 10 so as to prolong the freshness and/or usability of the product. It may also be advantageous to absorb the carbon dioxide given off by the product to maintain the integrity of the container 10 once the container 10 is sealed with the product is disposed within the container 10. For example, absorbing the carbon dioxide given off by the product may prevent a sealed container 10 from rupturing or otherwise failing.
Such example methods may also include sealing the container 10 to form a sealed container 10 containing the carbon dioxide absorber, the oxygen scavenger, and the product. For example, after the carbon dioxide absorber, the oxygen scavenger, and the product have been disposed within the container 10, the lid 12 may be heat-sealed, adhered, and/or otherwise connected to the container 10 such that a substantially fluid-tight seal is formed between the lid 12 and the container 10. While disposed within the container 10, the product may emit carbon dioxide. Thus, such an example method may include absorbing, with the carbon dioxide absorber, carbon dioxide given off by the product within the container 10. In such methods, absorption of the carbon dioxide by the carbon dioxide absorber may produce water. In some embodiments, the water produced during the absorption of carbon dioxide may be in the form of water vapor.
In example embodiments, the sachet 24 may be formed from at least one of a carbon dioxide permeable material, an oxygen permeable material, and a water vapor permeable material to facilitate the absorption of carbon dioxide, oxygen, and/or water. Additionally, the container 10 may be formed from any of the polymers or other materials described herein, and may have any desired permeability characteristics. For example, the container may be formed from a material such as polyethylene, polypropylene, or other like polymers, and such materials may be substantially impermeable to carbon dioxide, oxygen, and water in both liquid and/or gaseous form.
If keeping the environment within the package free from water or water vapor, is important the absorber may be packaged in a material that is permeable to carbon dioxide and oxygen, but impermeable to water vapor. This would allow an absorber to be produced that doesn't require any excess moisture and is promoted by absorbing carbon dioxide rather than water vapor.
Such an example method may also include at least partially promoting oxygen absorption by the oxygen scavenger disposed within the container by using the water produced during the absorption of carbon dioxide. Preferably, the carbon dioxide absorber is disposed with respect to the oxygen absorber so that the water created by the carbon dioxide absorber is available to the oxygen absorber to facilitate the absorption of oxygen. This availability of water to facilitate the absorbtion of oxygen is what is meant by the terms “promote” or “promotion.”
In such embodiments, the water vapor absorber or other like components described herein may be omitted. Thus, using the water produced during the absorption of carbon dioxide to at least partially promote the oxygen absorbers activity may reduce the cost and complexity of manufacturing sachets 24 of the present disclosure.
Even more preferably, the oxygen absorber can be a finely divided metal powder such as iron that is coated with a halogen salt such as sodium chloride. Such coated particles absorb oxygen very slowly at best until water is available to form an electrolyte which greatly enhances the speed of oxygen absorption. Upon promoting the oxygen absorption reaction, the oxygen scavenger may begin absorbing oxygen within the container 10, thereby maximizing the useable life of the product.
In order to create an effective version of this absorber, it is important to consider the amount of carbon dioxide that is needed to be absorbed. From this, determining the amount of material needed to absorb a given amount of carbon dioxide, the amount of water produced, and therefore the maximum amounts of iron that can be oxidized and oxygen that can be absorbed is easily done to stoichiometry.
For the absorption of carbon dioxide, calcium hydroxide absorbs carbon dioxide to produce calcium carbonate and water based on the following equation:
Ca(OH)2+CO2CaCO3+H2O
That is, in order to absorb one mole of carbon dioxide, one mole calcium hydroxide is needed which produces one mole of water
For the absorption of oxygen, there are multiple paths for the oxidation of iron, however, the most complete is described as:
4Fe+3O2+6H2O→2(Fe2O3+3H2O)
From this it is apparent that to absorb three moles of molecular oxygen, it requires six moles of water and four moles of iron, or more succinctly 1.5 moles of water is required to oxidize one mole of iron with 0.75 moles of oxygen.
As illustrated above, one mole of calcium hydroxide produces one mole of water when it reacts with one mole of carbon dioxide. From this, it is apparent that 1.5 moles of carbon dioxide can be absorbed by 1.5 moles of calcium carbonate to produce 1.5 moles of water which will react with a maximum of one mole of iron to absorb a maximum of 0.75 moles of oxygen. From this is easy to work out the amount of material needed to absorb a given amount of oxygen or carbon dioxide, or to determine how much carbon dioxide or oxygen can be absorbed from a given material.
Is important understand that the moles of iron represent the maximum amount of iron that can be reacted with the amount of water produced. This reaction could be slow. Additional water and a salt or the like may be required to create electrolytes to accelerate the oxidation reaction, therefore reducing the total amount of water available for the oxidation reaction itself. An additional consideration is that instance is that if there is too much water, the oxidation reaction could actually be quenched or more seriously the excess water can reach out the formulation and potentially contaminate the product is trying to protect.
While these calculations are all done in moles is very easy to convert these into grams. The critical molar masses are included in the following table:
The methods described above may be employed with any of the containers described herein. Additionally, although the above methods have been described in relation to the use of a sachet 24, in further embodiments, such methods may also be used in conjunction with the various films, ribbons, carriers, cloths, tablets, rings, or other structures described herein. For example, in additional embodiments, one or both of the carbon dioxide absorber and the oxygen scavenger may be embedded in a film or other like structure, and the film may be disposed within the inner cavity of the container 10. Alternatively, the film may be adhered to, embedded within, and/or otherwise connected to the sidewall 14 and/or the lid 12.
In the embodiment of
In the embodiment of
The carrier 40 is designed to be held by gravity in the single use coffee container 10 which narrows towards the bottom 16. It is also possible that a stop could be molded into the side of the container on which the carrier would rest. It is also possible that the carrier 40 could be held in place by adhesive. Further, it is possible that the carrier could be provided with a jagged edge or wavy edge to aid in draining of the coffee from a single use container.
In
In
While the above illustrations have shown particulate absorbents it is also possible that the absorbents could be incorporated into a plastic film, placed in a permeable capsule or pressure formed into a tablet. The tablet then may be covered with a gas permeable film or coating. The tablets, pieces of film, extruded polymer, or sachet as illustrated could be it in the cup of the carrier.
The cup 42 is shown as a separate member that is inserted into the carrier 40. The cup may be held in the carrier by spin welding, ultrasonic welding or pressure fitting. However, the cup in another preferred embodiment could be integrally molded with the absorber carrier. Further, it is possible that the carrier itself could be formed of a polymer that contains at least one of oxygen scavenger, carbon dioxide absorber, and dehumidifier material. If the support itself was formed of a material that absorbs oxygen and/or carbon dioxide it would only be necessary to form holes in the support for drainage and/or have irregular edge on the carrier. No cup would be necessary. Further, while the cup is illustrated in substantially the same height as the thickness of the support in several embodiments, it can be made deeper in order to hold more absorbents. Further the cup could be closed by a plug or a fitted cover. The cup also could be a preformed gas permeable can that is bonded to the carrier.
It is possible to utilize material containers for ingestible drinks that are quite permeable to gases such as oxygen, water vapor, and/or carbon dioxide. The containers are then sealed inside a bag that is impermeable to oxygen and carbon dioxide and water vapor. The bag has oxygen absorbers and/or carbon dioxide absorbers and/or water absorbers placed into the bag before it is sealed. The bag is opened immediately before use so that the ingestible drink such as cocoa does not lose freshness before use. Absorbers in the cup would prevent deterioration after the bag is opened and the individual containers are stored until use. The permeable container may be formed of a biodegradable material, such as poly lactic acid (PLA) or a copolymer of PLA and another polymer such as polyethylene or an acrylic. Alternatively, the cups could be formed of a thin, low cost or very thin polymer, permeable to oxygen, carbon dioxide, and water vapor. The bag may be foil, polyvinyl alcohol, or high-density polyethylene, preferably in layers that allow the best barrier property to be achieved in the bag.
Any suitable resin may be utilized in the invention for the polymer that holds the oxygen scavenger or other sorbent. The polymer holds the sorbent so that it will not be carried into the coffee or other food product when the container is used, but allows gas to reach the absorbent. Polymers useful for making the oxygen scavenging and absorbent articles can include common polyolefins such as low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), high impact polystyrene (HIPS), polycarbonates (PC), poly(methyl methacrylate) (PMMA) and their derivatives or copolymers.
Polymers suitable for the invention and biodegradable include common polymers generated from renewable resources and biodegradable polymers such as polylactic acid copolymers, starch based polymers such as thermoplastics starch, polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB). Biodegradable polymers that are petroleum based such as polyethylene oxide and polyvinyl alcohol (PVOH) are also included.
The invention uses common plastic article fabrication processes that include extrusion, injection molding, extrusion coating, lamination, tableting and compounding to form the sorbent structures including oxygen scavengers, CO2 absorbers, and moisture regulators.
While the invention is discussed with respect to the utilization of a food container for instant coffee, instant tea, and cocoa, the concepts and container of the invention are also suitable for other uses. The containers disclosed would be suitable for use in other food products where water or other liquids are added to the material contained in the container and wherein a changed liquid is withdrawn after dissolving or dispersing the food product. Typical of such materials would be tea, soup, milk components, and soup broth. The containers also could be used for medical products that are shipped as solid particles or are concentrated and then a carrier liquid is passed through the cup and through the concentrated liquid or solid particles to result in a medicinal liquid. An example of this would be drugs, such as powdered narcotics, such as morphine and methadone hydrochloride, and materials utilized as radiology tracers. They could also be used for alcoholic mixers.
The calcium hydroxide utilized for absorption of carbon dioxide may be utilized as discussed in the previous paragraph. Further the calcium hydroxide may be utilized in absorption of carbon dioxide from other food materials that are not packaged for dissolving in a fluid. These would include food materials such as cheese, kimchi, coffee, and any fermented product. The calcium hydroxide products for carbon dioxide absorbers also may be utilized for absorbing carbon dioxide given off by electrical products. The calcium hydroxide materials may be utilized as a preferred material for any storage where rapid absorption of carbon dioxide after packaging is desired.
The invention method of placing scavenger materials in a container, as stated above, could be used for packaging of products that are sensitive to moisture. Such products include many medicines and food products. Such food products as flour, drink mixes, gelatin desserts, and salt or other seasonings are subject to deterioration if moisture is present in the container. Moisture absorbent materials such as disclosed in U.S. Pat. No. 5,322,701-Cullen, herein incorporated by reference, could be placed into containers to enable longer storage of such materials. Suitable moisture absorbent materials include calcium oxide, silica gel, molecular sieve, and cellulose fibers.
The following are methods for making a solid oxygen absorbing composition or coating for use in the invention.
The oxygen scavenger may be in the form of a powder blend in a sachet or a pressed solid formed from compressed particles and binder. A method of making a compressed or pressed oxygen absorbing disc, tablet, wafer, washer, or capsule is as follows. Forming a blend of powdered absorbent based on iron powder with sodium chloride as an electrolyte, silica gel, and a binder that does not need to be heated very high in temperature. The binder can be a fine powdered polyethylene that will soften when under a pressure of between 3,000-50,000 pounds per square inch. The composition can also be heated to set or cure the binder but it cannot be heated above the boiling point of water to keep the moisture in the carrier. A suitable composition by weight would be about 18% polyethylene, 40% iron powder, 30% silica gel, 8% water and 2% sodium chloride. It is best to use a resin binder with a softening point above the boiling temperature of water.
A method for making an oxygen absorbing compound would be to put the oxygen absorbing composition in a thermoplastic material so that the oxygen absorbing compound could be filled into a container as a liquid ring and allowed to set or harden. This composition would be by weight about 40% thermoplastic resin, 30% iron powder, 20% silica gel, 9% water and 1% sodium chloride. An additive, such as CaCO3, clay, or talc, could be used to increase the porosity of the resin and to increase the rate of oxygen absorption. This absorbent composition could be deposited into a container or made into a tape that could be put onto the inner sides of the container. The thermoplastic resin can be a vinyl acetate, ethyl vinyl acetate, polyurethane or combinations thereof.
Another method for making an oxygen absorbing composition is dispersing the oxygen absorbing composition into a polyvinylchloride plastisol. These plastisols are used as cap liners and as gaskets in caps and jar lids. This oxygen absorbing plastisol composition may then be put into the cup as a liner, a ring or coating along the sides or bottom edge of the cup. This composition would be semi liquid and could be placed into the cup and allowed to set. The plastisol may be selected from high-density polyethylene, high density polypropylene, acrylic vinyl acetate ethylene copolymer, ethylene vinyl acetate, vinyl acetate homopolymer, acetate ethylene copolymer, plasticized vinyl chloride, oxidized polyethylene homopolymer and polyurethane. The preferred plastisol is polyvinyl chloride as it does not react with foods and is resistant to the temperature of boiling water. The oxygen absorption composition can be up to 75% by weight with the other 25% being the polymer. One composition was 10.35 grams of polyvinylchloride plastisol, 12.51 grams of iron powder containing 2% by weight sodium chloride.
Illustrative of a plastisol material is polyvinyl plastisol in an amount of 10.35 grams was blended with 12.51 grams of 200 mesh iron powder containing 2% by weight sodium chloride. The blending was done with an electric high-speed mixer. A sample of the resulting composition was coated onto a container cap. The rate of oxygen absorption was measured over time.
The test vessel contained 500 cc of air or 100 cc of oxygen. The test was conducted at room temperature with a moisture source in the test vessel.
Another invention composition would be to disperse the sorbent composition in a multiple component carrier such as an emulsion, dispersion, suspension or other mixtures. By dispersing the sorbent in such a multi component system the resulting composition can be more easily applied to a cup as an oxygen scavenger or sorbent coating. These types of coatings can contain more of the oxygen absorbing composition and have greater permeability for oxygen. By not fully drying the water based systems we can have a self-promoting and self-reacting oxygen absorbing coating. Glucose oxidase can be used in place of the iron. A xanthan gum emulsion, alginate emulsion or microcrystalline cellulose system can also be used. This system can also contain water in the iron based oxygen absorbing system. Adhesive based emulsion can also be used such as acrylic polymer emulsions in water, a polyvinyl acetate in water emulsion, and a vinyl acetate ethylene copolymer in water emulsion can be used. The oxygen absorbing composition would be an iron powder with sodium chloride as an electrolyte and a moisture carrier. The moisture carrier can be silica gel, hydrogel or any other moisture carrier that can hold moisture. In oxygen absorbers, it is also possible to not fully dry the moisture out of the emulsion thereby leaving some moisture in the coating. An alginate gel would be by weight percent 2.25% sodium alginate, 1.0% polysorbate 80, 0.2% sodium propionate and 96.55% distilled water. A xanthan gum emulsion would be by weight 2.0% xanthan gum, 43% isopropyl alcohol and 55% water. These two emulsions could be combined 1 part emulsion with 1 part oxygen absorbing composition composed of 99% iron powder and 1% sodium chloride as the electrolyte. The oxygen absorbing composition can be a fine iron as fine as 2-5 microns in particle size to improve the clarity of the oxygen absorbing coating or oxygen absorbing compound. A thin film layer or coating can be put over the final coating to insure that no oxygen absorbing ingredients or sorbents migrate out over time. This thin film cover can a cellulose acetate polymer, vinyl acetate ethylene copolymer, vinyl acetate homopolymer, acetate ethylene copolymer, plasticized vinyl chloride polymer, acrylic polymer or an oxidized polyethylene homopolymer.
The water absorbers and carbon dioxide absorbers may be placed into the polymer by a substitute for the oxygen absorbers. The preferred water vapor absorbers are silica gel and molecular sieve materials.
Any suitable transition metal, typically including zinc, copper, iron, cobalt and zirconia, may be utilized in the oxygen scavenger of the invention. The preferred oxygen scavenger of reduced iron powder preferably has 1-200 um mean particle size, more preferably 5-50 um mean and most preferably 10-40 um mean. The iron can be mixed with salt or a combination of different electrolytic and acidifying components. The iron particles can, in a preferred embodiment, also be coated with electrolyte salt. The combination and relative fraction of promoting electrolytic and acidifying components coated onto the iron particles can be selected according to the teachings of U.S. Pat. No. 6,899,822 and co-assigned published U.S. Patent Applications 2005/0205841 and 2007/020456, incorporated herein by reference. The coating technique is preferably a dry coating process as described in the references above.
The salt can be any salt such as sodium, potassium or calcium based ionic compounds that are soluble in water. Typical examples include NaCl, KCl, Na2HPO4 and others. A mixture of separate electrolytic and acidifying salt components can be advantageously used in the formulation as described in prior art. Sodium chloride is preferred because it is effective and low in cost.
The oxygen scavenging fabricated article may contain moisture regulators based upon silica gel, molecular sieve, activated carbon, clay or other minerals. The compounds may contain various levels of water to achieve water activities ranging from 0.01 to 0.85.
The film/tape/ribbons/wafers/washers used in the invention may be a single or multilayer films that are porous or solid, and consisting of iron-based oxygen scavengers and electrolytes, such as disclosed in co-assigned U.S. patent application Ser. No. 12/416,685, filed Apr. 1, 2009, hereby incorporated by reference and U.S. Patent Publication No. 2010-0255231, published Oct. 7, 2010, also hereby incorporated herein by reference. The film optionally consists of moisture regulators with a chosen water activity. The film may be in circular or strips that can be fitted into a container as a bent strip. Multilayer film is preferred with oxygen scavenger or other absorber embedded inside the film and not exposed on film surface. Films with some porosity or voids are preferred to facilitate the rate of oxygen, carbon dioxide, or water vapor absorption. Moisture regulator can be incorporated into the film during extrusion or from post-extrusion processing. The films can be laminated to the lids or container sides.
The insert may be a ring shaped oxygen scavenging article as in
In the embodiment using strands/paste, such as in
A method to remove CO2 in the package is described as follows: using a scavenger specifically designed for CO2 absorption. A packet made of a gas permeable polyolefin film containing carbon dioxide absorbing particulates is packaged in a single use container to absorb the off-gasses. The preferred packet will have high gas permeation and low water vapor permeation properties. The absorber will be capable of absorbing a high concentration of CO2 and not interfere with the aromatics components of the human ingestible material. The CO2 absorber can contain certain amount of calcium hydroxide, silica gel and water, with other ingredients. Optionally calcium hydroxide may be replaced with other hydroxides such as sodium hydroxide and potassium hydroxide or mixtures of these and other hydroxides. Optionally, alkaline, alkaline earth or metal oxides may be used in conjunction with or replacing hydroxides. The oxides include but not limited to calcium oxide, aluminum oxide and magnesium oxide. These oxides may be used in mixture format. For reference, the range and formulations useful as CO2 absorber are described in U.S. Pat. No. 5,322,701 assigned to Multiform Desiccants, Inc., hereby incorporated by reference.
As described for the oxygen absorbing materials above the oxygen and carbon dioxide scavenging formulations may be packaged in a format other than a packet. The carbon dioxide scavenging formulations may be enclosed in oxygen or carbon dioxide permeable capsule or a tablet that may be coated with a permeable or semi-permeable polymer material. Any resin or polymer permeable to oxygen and/or carbon dioxide may be used to coat the tablets. Water base polymer coating of the tablets is preferred. Preferred coating polymers are hydroxyl propylmethyl-cellulose or acrylic water base coatings. They may also be fabricated in a compact form, such as a washer, wafer, disc or platelet, wrapped with a coating or polymer film that is gas permeable or semi-permeable. The coating method of making the disc, platelet or tablet can include dip coating, spray coating, flash coating, spin coating or any other known methods that are applicable to forming the product. The film method can include overcoating, lamination, multilayer lay up followed by die-cutting, and any other known methods that can make film composite layered articles. The methods of forming oxygen absorbents above may be used for forming sorbent materials for CO2 absorbents and water vapor absorbents.
Alternatively or additionally, the sachet, grooves, film, or cup may contain a CO2 absorber capable of absorbing the CO2 emitted from the coffee permitting it to be packaged a short time after roasting thereby minimizing loss of flavor through volatilization. It is also possible that a carbon dioxide absorbing sachet could be used in addition to the oxygen absorbing sachet.
Alternatively or additionally, sachet, the grooves, film or cup may contain a moisture regulating formulation capable of maintaining the water activity of the instant coffee or other food product such as instant tea, at an optimum level so that it is not too dry or too moist which can affect the extractability of the flavor elements.
The container may be provided with an oxygen absorbent film or other sorbent film that is in cup 42. The film may be cast, laminated or extrusion coated into the cup or preformed and attached to the cup by adhesives, ultrasonic sealing, or heat sealing. The oxygen absorbent film may consist of multilayer structure in which the oxygen absorbent is in the inner layers of the structure. The film may be provided with an abrasion resistant layer or a slippery layer, not shown, that will provide abrasion resistance or slippage so that the filter's movement will not be able to remove the oxygen absorbent (scavenger) materials from the film. The resistance or slippage layer may be formed of polyethylene, polypropylene, polyamide and their copolymers. Conventional slip additives may be added into the layer that contacts the coffee to result in a coefficient of friction of 0.5 or below, preferably 0.3 or below. While described with reference to an oxygen absorbing film, it is possible that the film only contain CO2 absorbing materials, or water absorbing materials. It is further possible that it contain a combination of carbon dioxide, oxygen absorbing, and water absorbing materials.
The oxygen scavenger or other gas absorber may be placed in cup 42 by a variety of techniques, but an extrusion technique, such is utilized for hot melt adhesive is quick and may be done during manufacturing prior to the support 40 being put in the cup. The extrusion materials include hot melt polymers as well as plastisol materials discussed above that would cure in place.
Any suitable resin may be utilized in the invention for the carrier and the absorbent film polymer that holds the oxygen scavenger, carbon dioxide absorbent, water vapor absorber, or other sorbent. The polymer holds the sorbent so that it will not be carried into the instant coffee, cocoa, or other food product when the container is used. Polymers useful for making the oxygen scavenging and absorbent articles can include common polyolefins such as low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), high impact polystyrene (HIPS), polycarbonates (PC), poly(methyl methacrylate) (PMMA) and their derivatives or copolymers.
Polymers suitable for the invention container and carriers and biodegradable include common polymers generated from renewable resources and biodegradable polymers such as polylactic acid copolymers, starch based polymers such as thermoplastics starch, polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB). Biodegradable polymers that are petroleum based such as polyethylene oxide, polyvinyl alcohol (PVOH) are also included.
The invention uses common plastic article fabrication processes that include extrusion, injection molding, extrusion coating, lamination, tableting and compounding to form the sorbent structures including oxygen scavengers, CO2 absorbers, and moisture regulators.
The oxygen scavenging fabricated article may contain moisture regulators based upon silica gel, molecular sieve, activated carbon, clay or other minerals. The compounds may contain various levels of water to achieve water activities ranging from 0.01 to 0.85. In the event that only protection from deterioration of the mammal ingestible material by action of water vapor is desired the n the absorber and moisture regulator silica gel, molecular sieve, activated carbon, clay, or other minerals may be used without the oxygen scavenger or carbon dioxide absorber. Silica gel is preferred as it is low in cost, effective, and safe. Moisture absorbent materials such as disclosed in U.S. Pat. No. 5,322,701—Cullen, herein incorporated by reference, could be placed into containers to enable longer storage of moisture sensitive materials.
The film/tape/ribbons for use in cup 42 of the invention may be a single or multilayer films that are porous or solid, and consisting of iron-based oxygen scavengers and electrolytes, such as disclosed in co-assigned U.S. patent application Ser. No. 12/416,685, filed Apr. 1, 2009, hereby incorporated by reference. The film optionally consists of moisture regulators with a chosen water activity. Multilayer film is preferred with at least one of water vapor absorber, carbon dioxide absorber, or oxygen scavenger embedded inside the film and not exposed on film surface. Films with some porosity or voids are preferred to facilitate the rate of absorption. Moisture regulator can be incorporated into the film during extrusion or from post-extrusion processing.
The following examples are used to illustrate some parts of the invention. The Examples are illustrative and not exhaustive of the embodiments of the invention. Parts and percentages are by weight unless otherwise indicated. The examples use ground coffee as the test material to show the oxygen scavenging effectiveness. As they are effective with ground coffee, they will also be effective in the container of the instant invention.
An extruded film that contained oxygen scavenger formulations was prepared by following a method described in co-assigned U.S. patent application Ser. No. 12/416,685, filed Apr. 1, 2009, hereby incorporated by reference, to test the oxygen scavenging behavior with the presence of coffee. The film was extruded from a mixture of 17/3/80 weight ratio of iron, sodium chloride and low density polyethylene from a film extrusion process. The materials were pre-mixed in a container and fed into a twin screw extruder with the extruder and die temperatures set at 220° C. Films, approximately 9 mil thick, were extruded from a 6″ die and collected on a spool. The 9 mil film samples, cut in approximately 1″ square pieces, were moisturized by placing drops of water on the surface of the film and blotted to remove dripping water. The films were placed in 7″×7″ plastic barrier bags with a package of approximately 8.8 gm ground coffee sealed in Tyvek breathable film bag. The barrier bag was hot sealed and injected with 150 cc O2/N2 mixture to reach an initial oxygen concentration of 3% or lower. The oxygen scavenging rate was measured by using MOCON PacCheck Model 450 Head Space Analyzer.
As a control, a separate barrier bag that consists of approximately 8.8 gm ground coffee removed from a container, conditioned in ambient temperature and environment for more than one hour, was sealed in Tyvek breathable film bag without scavenger, and was tested for oxygen concentration change over the same time period.
Oxygen scavenging film was extruded with a mixture of 5.1/0.9/94 weight ratio of iron/NaCl/PLA in which PLA was NatureWorks PLA 2002D resin. The iron is the same as in Example 1. The composition of poly (lactic acid) resin (PLA) was pre-dried in a desiccant oven at 60° C. for at least 4 hrs before extrusion. The mixture was extruded in a twin screw extruder to make 4″ wide and 4 mil thick films. A coffee lidding foil film peeled from a Green Mountain 55 cc cup coffee was used for lamination test. Dow Chemical Integral™ 801 adhesive film was used as an adhesive for lamination test. The extruded Fe/PLA film was stacked with the Integral film and the lidding film to form Fe/PLA-adhesive-lidding sandwich structure. The structure was heat pressed in a heat sealer to form an oxygen-scavenging lidding structure.
Packets with an approximate size of 1″×0.5″ made of a polyolefin film containing iron-based oxygen scavenging formulation and moisture regulator were used for the test. The packets contained iron-based scavenger and a moisture retaining material patented by Multisorb Technologies. The packet consists by weight of approximately 40% iron, 10% NaCl, 50% silica gel and some moisture. The packets had a water activity in the range of 0.4-0.8. The packets were stored with coffee in 150 cc barrier bag and tested as described in Example 1. The oxygen absorption property was measured by using MOCON PacCheck Model 450 Head Space Analyzer.
An acrylic emulsion was made using Neocryl A-5117 from Zeneca Resins. A formulation comprising 50 weight percent of this acrylic emulsion and 50 weight percent of a 200 mesh electrolytic iron reduced iron containing 2 weight percent sodium chloride was coated on eight square inches of a polypropylene substrate and dried with heat. The coat weight was 0.0135 grams per square inch. This oxygen absorbing coating was then placed inside of a test vessel with 500 cc of air or 100 cc of oxygen along with 2 square inches of a moisture saturated blotter paper. Three samples were tested.
A polyvinyl acetate in water emulsion was made using Vinac XX-210 from Air Products. Forty three weight percent of this polyvinyl emulsion was combined with 57 weight percent iron blend containing 200 mesh electrolytic reduced iron powder containing 2 weight percent of sodium chloride. This formulation was then coated on to eight square inches of a polypropylene substrate with a coat weight of 0.026 grams per square inch. The resulting coating was then placed inside of a test vessel with 500 cc of air or 100 cc of oxygen. A moisture source was also placed inside of the test vessel along with the sample. Three samples were tested.
VitaCal-H calcium hydroxide (Ca(OH)2) powder was obtained from Mississippi Lime Company. The as received powder was mixed with ground silica gel (SG) powder that had a mean particle size of approximately 6 micron with a by weight mixture ratio of VitaCal-H/SG=75/25. The mixture was then blended with Petrothene GA502024 low density polyethylene resin obtained from LynodellBasell Industries to achieve the following blend weight ratios: Ca(OH)2/SG/LDPE=30/10/60 and 40/10/50
The blends were extruded in a single screw extruder with a flat sheet die attached to the extruder to make sheet materials. SAFOAM FPN3-40 obtained from Reedy International Co. was added in some runs to make samples that contained some voids or porosity. The extruder was set at 160-220° C. temperature range and the die was at 220° C. The extruded sheets, approximately 30-40 mil thick, were air cooled and winded on a roll.
Samples, approximately 0.4-0.7 grams were cut from the extruded sheets and used for carbon dioxide scavenging test. The samples were pre-hydrated with water to obtain approximately 1 to 5% water content determined by weight gain. The samples were then sealed in foil pouches filled with 600 cc gas that contained approximately 25-20% carbon dioxide balanced with nitrogen. The concentration of carbon dioxide was measured using a MOCON model 333 Pac-Check analyzer for various periods of time. The scavenging test data in terms of cc of CO2 absorbed is shown in Table-1. The formulations listed are weight ratios of Ca(OH)2/SG/LDPE. Safoam was added as additional percentage. The data showed that carbon dioxide was absorbed effectively with the increase of time from 24-72 hrs.
Ca(OH)2 and silica gel used were the same as that of Example 7. Solka-floc wood fiber was obtained from International Fiber Company. Polypropylene was Sunoco CP360H resin, an elastomer Kraton G1657 was obtained from Kraton Polymers. These materials were blended to form the following material weight ratios: Ca(OH)2/SG/Solka-floc/PP/Kraton 1657=48/6/6/36/4
The materials were compounded in a twin screw compounding machine at 200-250 C temperature and extruded into strands, cooled in water and pelletized. The compounded pellets were injection molded in a single shot injection molding machine to form 1.3″ diameter discs. The discs were tested for carbon dioxide scavenging performance following the procedure described above. The test data showed that the discs gradually absorbed carbon dioxide with the test time. The absorbing rate was found increased when the disc surfaces were roughened with a sand paper prior to hydration. Table-2 shows the data of an injection molded disc, sanded and hydrated with 1% water prior to test.
Coating formulations were prepared by using the same sorbent ingredients as described above. Luvitec K30 (BASF) polyvinylpyrrolidone (PVP) and polyethylene glycol 6000 (Aldrich Chemical) were used to make the coating solutions. PVP was dissolved in water to form a 17 wt % solution. PEG was dissolved in water to form a 48 wt % solution. Both solutions were clear and without residues. A mixture of the PEG and PVP solutions was made with 90/10 ratio to achieve a resin content of approximately 45% in water. The solutions were used to mix with Ca(OH)2 and SG to form a coating solution that has the following coating formulation: Ca(OH)2/SG/(PEG/PVP)=40/10/50
The solutions were coated on an 20 mil paperboard substrate and dried in oven at 115 C for more than 2 hours to remove the water. The coated samples were cut and hydrated with wet sponge to be used for carbon dioxide scavenging test by using the same test method described above. The test data is shown in Table-3. It is seen that carbon dioxide was absorbed rapidly over the test time period.
Another coating solution was prepared by dissolving hydroxypropylcellulose resin (Hercules Klucel EF) in water to form a uniform solution. Ca(OH)2 and SG were mixed with the solution to form a paste formulation approximately Ca(OH)2/SG/Klucel=70/10/20 weight ratios. Klucel served as a binder for the solid formulation. The paste formulation was pressed on the same paperboard and dried to form a porous coating. The pressed-coating, although brittle, maintained integrity for test. It was hydrated with wet sponge and the weight gain was recorded. This high solid loading sample was tested for CO2 scavenging performance. The data in Table-4 showed that CO2 was absorbed rapidly over the test time period with high absorption capacity.
Plastic capsules were hand filled with Multisorb Technologies CO2 absorbing formula (semi-dry flow able granules) to achieve a CO2 free environment. The capsules are breathable, semi-rigid, and are partially resistant to hot water. The device (capsule) provides for a timed absorption of CO2 from coffee filled pods stored at various temperatures. The CO2 capsule limits the expansion of a non-breathable cup (from CO2 emissions from coffee) and also enhances or maintains the aromas and oils of the freshly roasted coffee powders and granules. The formulation enclosed in the capsules were Ca(OH)2/SG=67/33 ratio with the silica gel containing water. The net formulation was Ca(OH)2/SG/H2O=67/20/13 weight ratio. The blend was in loose powder format contained in the capsule. The CO2 scavenging data is shown in Table-5.
The formulation used in Example 10 was compressed into tablets in a mold on a conventional cold or hot pressing machine. The tablets were then coated with polyethylene powders on the surface. The coated tablets were heated in a heating chamber at a temperature below the melting point of polyethylene but hot enough to fuse the coated powder particles. The coated tablets were conditioned at room temperature in 80% relative humidity environment for 16 hrs. The tablets showed CO2 scavenging properties as listed in Table-6.
Ca(OH)2 and silica gel used were the same as that of Example 7. Solka-floc wood fiber was obtained from International Fiber Company. Polypropylene was Sunoco CP360H resin, an elastomer Kraton G1657 was obtained from Kraton Polymers. These materials were blended to form the following material weight ratios: Ca(OH)2/SG/Solka-floc/PP/Kraton 1657=48/6/6/36/4
The materials were compounded in a twin screw compounding machine at 200-250 C temperature, cooled in water and pelletized. The pellets will then be ground to relatively small particle size which will then expose portions of the active ingredients. This exposure will increase the adsorption rate. The ground active material is then fused together under heat and pressure which is applied to the material in a mold. The results are a porous sintered structure that increased active surface area.
A gas permeable polyethylene film sachet container is filled with 1.1 g of calcium hydroxide of 200 mesh and 1.1 g of silica gel in a 2:1 blend with water. The sachet is sealed and placed into a shrink wrap package of 4 ounce of Swiss cheese using conventional grocery cheese wrap packaging techniques. After four months storage at about 40° F. the cheese exhibits good color and taste. Further, the package is not expanded.
This example illustrates the rapid acting of the calcium hydroxide in absorption of carbon dioxide.
As a control sachets containing calcium oxide an amount of 1.1 g and 0.9 g of white porous silica gel and water in a 2:1 ratio are formed. The sachets are each placed into an impermeable bag that is filled with 300 cm3 of a bout a 30% by weight carbon dioxide and oxygen gas mix. The three samples are sampled at two hours, four hours, six hours, 24 hours, 48 hours and 72 hours. The results are illustrated in Table 1 below
Three sachets containing 1.1 g of calcium hydroxide (200 mesh) and 1.1 g of a mixture of water and silica gel in a 2:1 ratio are formed. The sachets are placed in a bag containing carbon dioxide as indicated above for the calcium oxide test and are sampled two hours and 24 hours. The results are illustrated in Table 2 below:
As may be seen from the comparison of Table 1 and Table 2 there is a much faster pickup of the carbon dioxide by the calcium hydroxide. This is shown by the rapid decrease in carbon dioxide left in the bag.
The materials of the above Examples 1-13 may be utilized in the invention as scavengers or absorbents. Water vapor absorbers could be made by similar techniques using silica gel and molecular sieve materials.
A further embodiment of the invention focuses on instances where the absorber will be used in high carbon dioxide concentration environments and there is a need for a rapid absorption of headspace oxygen. In these instances the purpose of the carbon dioxide absorber is not necessarily to absorb carbon dioxide, but to produce enough water to promote the oxygen absorption reaction. A typical example of this would be in instances where oxygen sensitive products are placed in the barrier containers that are gas flushed with high concentrations of carbon dioxide. While gas flushing removes most of the ambient oxygen, small amounts of oxygen still remain in the packaging, which could be detrimental to the meat product. Therefore desirable to remove this headspace oxygen to prevent degradation of the product.
Typically this is done with an oxygen scavenger that has had additional water added to accelerate the reaction. This is not necessarily desirable as exposure to oxygen prior to insertion or during the packaging process can cause these highly reactive absorbers to start absorbing oxygen and lose most of their potency before it is needed. To remedy this, a water generating composition that generates water by reacting a carbon dioxide, such as calcium hydroxide, can be added to oxygen absorbers that are intended to be placed in high carbon dioxide environments. In these instances the carbon dioxide absorber would generate the water needed to promote the oxygen absorber. This is even operable in instances where an immediate pickup is desired and water must be added to the sachet. In those instances just enough water can be added to the sachet to keep the overall water activity of the composition below what is required to promote the oxygen absorber. The water generating composition can then generate just enough water to put the overall water activity of the absorber into a range where the oxygen absorbing composition can react with the ambient oxygen. To prevent the absorber from the absorbing oxygen prematurely by accidentally picking up ambient moisture, the sachet itself can be made with material that is impermeable to water and water vapor, but permeable to carbon dioxide oxygen. Olefins are a preferred material for this, including but not limited to polyethylene and polypropylene, but any material that met this requirement would be acceptable.
An extension of this would be in using this same a method for oxygen absorbing films. In these instances, the water generating composition and oxygen absorbing composition would be compounded with a resin that is permeable to oxygen and carbon dioxide but not necessarily permeable to water or water vapor. From this composition if you could be made to any conventional film manufacturing means. This film could be used in a multilayer scheme in which one of the layers is impermeable to oxygen. This this would create an ideal oxygen barrier film to be used with high carbon dioxide environments, as oxygen ingress would be prevented by the barrier layer, and any head space oxygen would be absorbed by the layer containing the oxygen absorber and water generating composition.
The invention has been described in detail with particular reference to a presently preferred embodiment, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the appended claims, and all changes that come within the meaning and range of equivalents thereof are intended to be embraced therein.
The present application is a continuation-in-part of U.S. patent application Ser. No. 13/028,740 filed Feb. 16, 2011, which is a continuation-in-part of U.S. patent application Ser. No. 12/984,230 filed Jan. 4, 2011, which is a continuation-in-part of U.S. patent application Ser. No. 12/751,583 filed Mar. 31, 2010, each of which is expressly incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13028740 | Feb 2011 | US |
| Child | 14320192 | US | |
| Parent | 12984230 | Jan 2011 | US |
| Child | 13028740 | US | |
| Parent | 12751583 | Mar 2010 | US |
| Child | 12984230 | US |
