CN1925755B - Extending the Shelf Life of Plastic Packaging Using CO2 Regulators - Google Patents

Abstract

A method of replenishing carbon dioxide gas in a carbonated beverage container is disclosed wherein the carbon dioxide regulator releases carbon dioxide at a rate approximately equal to the loss of carbon dioxide from the container. Also disclosed is a packaging system for maintaining pressure consistency of a carbonated beverage comprising a lid, a plastic container, and a carbon dioxide regulator. Also disclosed is a method of making a packaging system for maintaining pressure consistency of a carbonated beverage comprising remolding a preform around a carbonation dispensing component, or mixing a carbonation regulator into a body used to form said carbonated beverage container in plastic materials. Also disclosed are carbon dioxide regulator compositions for replenishing carbon dioxide gas in carbonated beverage containers, the compositions comprising polycarbonates, organic carbonates or materials that absorb and subsequently release carbon dioxide.

Description

Extending the Shelf Life of Plastic Packaging Using CO2 Regulators

Cross References to Related Applications

This application claims priority to the following patent applications: Provisional Patent Application 60/548,286, filed February 27, 2004 and Provisional Patent Application 60/628,737, filed November 17, 2004, and Provisional Patent Application 60/628,737, filed February 24, 2005, named Provisional Patent Application for "Extending the Shelf Life of Plastic Packaging Using Carbon Dioxide Regulators."

Background of the invention

Plastic and metal containers are already replacing glass in the field of bottled beverages where ease of handling, low weight and unbreakability are required. Plastic packaging, especially polyethylene terephthalate (PET) bottles, has been widely used for packaging carbonated products such as beer, soft drinks, still water and some dairy products. Each of these products has an optimal carbonation or carbon dioxide (sometimes referred to herein as " _CO2 ") pressure within its packaging to maintain its optimal quality. In conventional plastic packaging, it is difficult to maintain the _CO2 pressure at this optimal level for an extended period of time.

The _CO2 can permeate the plastic packaging, allowing the pressure inside the bottle to decrease over time. Ultimately, after a certain amount of carbonation is lost, the product will no longer be suitable for use, usually manifested by a noticeable and unacceptable change in taste or taste. The point at which this happens often determines the shelf life of the package. The rate of _CO2 loss depends largely on the weight and size of the package and the temperature at which it was stored. A lighter, thinner bottle loses carbonation faster and cannot maintain a high internal pressure, resulting in a shorter shelf life. As plastic bottles get smaller, the relative rate of carbon dioxide loss becomes faster. Permeation is faster at higher temperatures, which reduces shelf life and makes it difficult to store carbonated beverages in plastic containers in hot weather and still maintain a reasonable shelf life. Longer shelf life, lighter, less expensive plastic bottles and the ability to store bottles longer without cooling have many economic advantages.

Various approaches have been taken to address the above problems. An easy way to prolong fizzy drinks is to add extra carbon dioxide when filling. This method is commonly used for carbonated soft drinks and beer, but its effectiveness has been hampered by the impact of overcarbonation on product quality and the resulting negative impact on the physical properties of the bottle. Small differences in the internal pressure in the package can cause a noticeable difference in the sparkling quality of the beverage. Dissolved _CO2 also affects taste. These precise requirements vary by product.

Percarbonation is also hindered by the pressure limit of the pack. It is possible to make the bottle more pressure resistant, but this would require the use of additional materials in the bottle construction or require more prominent higher performance plastics.

Carbonation can be maintained by reducing the _CO2 permeation rate. This typically involves applying a second barrier coating to the PET bottle, using a polymer that is more expensive and less permeable than PET, creating a multilayer bottle structure, or a combination of the above. These manufacturing methods are all much more expensive than the methods used in the usual production of polyester bottles and often create new problems, especially recycling.

In the prior art, carbon dioxide generating materials have been used to extend the shelf life of carbonated beverages. Molecular sieves treated with carbon dioxide have been used in carbonated beverages by reacting the bound carbon dioxide with water.

US Patent 6,852,783 to Hekal and US Patent Application 2004/0242746 Al to Freedman et al. describe a _CO2 releasing composition that may be incorporated or inserted into the packaging of carbonated beverages. The compositions of these references describe the incorporation of more than 25% by weight of inorganic carbonates as carbon dioxide sources into thermoplastics. A 32g PET bottle filled with 25% sodium bicarbonate has the potential to release 4.5g of carbon dioxide. This is about ten times higher than would be required in PET beer bottle use, potentially leading to unsafe pressurization of the packaging. And these structures release carbon dioxide too quickly to regulate pressure over long periods of time, especially if the structure is made of polyethylene terephthalate, as opposed to polyethylene, which has a lower moisture vapor transmission rate. This is even more so for the fabricated structures. Such high fills have been found to be unsuitable for use because of the potential to release too much carbon dioxide into the package.

Summary of the invention

The present invention relates to a method of replenishing carbon dioxide gas in a carbonated beverage container. The method includes inserting a carbon dioxide regulator into a beverage container or into a lid of the container and releasing carbon dioxide from the carbon dioxide regulator through a chemical reaction. The rate of release of carbon dioxide is adjusted to approximately equal the rate of loss of carbon dioxide from the vessel.

The invention also relates to a method of replenishing carbon dioxide gas in a carbonated beverage container. The method includes inserting a carbon dioxide regulator into the container or into a lid of the container, and subsequently adjusting the rate of release of carbon dioxide from the carbon dioxide regulator to approximately equal the rate of loss of carbon dioxide from the container.

The present invention also relates to a packaging system for maintaining pressure consistency of carbonated beverages comprising a lid, a plastic container and a carbon dioxide regulator.

The invention also relates to a method of making a packaging system for maintaining pressure consistency of carbonated beverages, the method comprising overmolding a prerorm around a component for a carbon dioxide regulator.

The present invention also relates to a method of making a packaging system for maintaining pressure consistency of carbonated beverages, the method comprising incorporating a carbon dioxide regulator into the plastic material used to form the body of said carbonated beverage container.

The present invention also relates to carbon dioxide regulator compositions for supplementing carbon dioxide gas in carbonated beverage containers, the compositions comprising polycarbonates alone, organic carbonates alone, or combinations thereof.

The present invention also relates to carbon dioxide regulator compositions for supplementing carbon dioxide gas in carbonated beverage containers, the compositions comprising materials that absorb and subsequently release carbon dioxide.

A "carbonated beverage" as used herein is an aqueous solution in which, in the case of a carbonated soft drink, the dissolved carbon dioxide gas is present in an amount of about 2 to about 5 volume _CO2 /volume _H2O , preferably about 3.3 to about 4.2 volume CO2/ _volume Volume _H2O , for beer, the amount of dissolved carbon dioxide gas is about 2.7 to about 3.3 volume _CO2 /volume _H2O .

As used herein, a "carbon dioxide regulator" is a composition that either slowly releases CO ₂ through a controlled chemical reaction process, or absorbs and releases CO ₂ through a physical process, wherein the rate of release is approximately equal to The rate of _CO2 loss from the package, thus keeping the CO2 pressure in the package more constant over time.

Suitable _CO regulators include: polycarbonates, cyclic organic carbonates, organic carbonates such as alkyl carbonates, ethylene carbonate, propylene carbonate, polypropylene carbonate, ethylene carbonate, glycerol carbonate esters, butylene carbonate, diethyl carbonate, ethyl pyrocarbonate, methyl pyrocarbonate, dialkyl dicarbonate or mixtures thereof; inorganic carbonates such as sodium bicarbonate, ferrous carbonate, calcium carbonate, lithium carbonate and mixtures thereof; molecular sieves, zeolites, activated carbons, silica gels and coordination polymers, metal organic frameworks ("MOF's") and isorecticular metal organic frameworks ("IRMOF's"). The amount of _CO2 regulator used depends on the desired release of carbon dioxide, which depends on the amount of carbon dioxide lost from the container over the storage time of the container.

Areas of the bottle where the _CO2 regulator can be placed include, but are not limited to: the cap, the mouth/neck, the bottom of the bottle, or mixed into the plastic resin that makes up the bottle.

Brief description of the drawings

Figure 1 depicts the effect of carbon dioxide regulators on the performance of PET beer bottles.

Figure 2 depicts the effect of carbon dioxide regulators on the performance of carbonated soft drink bottles.

Figure 3 depicts the CO2 regulator cap with the dish insert and gasket.

Figure 4 depicts the carbon dioxide regulator assembly with the disc and gasket.

Figure 5 depicts the CO2 regulator cap with the plug assembly inserted.

Figure 6 depicts the carbon dioxide regulator bottle mouth insert assembly.

Figure 7 depicts the carbon dioxide production of organic carbonates activated by water vapor.

Figure 8 depicts the effect of bagging material on the CO2 release rate.

Figure 9 depicts the loss of carbon dioxide as a function of the pressure inside the bottle.

Figure 10 depicts the presaturation of carbon dioxide in a 20 oz bottle.

Detailed description of the invention

A number of compositions can be used as carbon dioxide regulators. These compositions are divided into two categories. The first category is compositions that generate or release carbon dioxide through controlled chemical reactions. These compositions include: a) polymers such as aliphatic polyketones, which upon reaction with oxygen generate carbon dioxide as a by-product of dehydration, or upon hydrolysis, especially in the presence of acids, generate organic and inorganic carbonates releasing carbon dioxide. Catalysts, binders and other additives can be combined with these materials to assist in controlling the progress of carbon dioxide evolution; and b) organic carbonates such as alkyl carbonate, ethylene carbonate, propylene carbonate, polypropylene carbonate, Ethylene carbonate, glycerol carbonate, butylene carbonate, diethyl carbonate, ethyl pyrocarbonate, methyl pyrocarbonate, cyclic carbonate acrylates such as trimethylolpropane carbonate acrylate, and dialkyl dicarbonates , which release carbon dioxide upon hydrolysis, which hydrolysis can be enhanced by reaction with acids such as citric or phosphoric acid.

The second category is sorbent compositions, which store carbon dioxide and then release the carbon dioxide into the container when it is lost from the packaging. These compositions include: sorbents such as silica gel; molecular sieves, zeolites, clays, activated alumina, activated carbon and coordination polymers, metal organic frameworks or "MOF's" and iso-reticulated metal organic frameworks or "IRMOF's", the The "MOF's" and "IRMOF's" mentioned above are crystalline materials of metal oxides and organic acids similar to zeolites. These materials can be processed into various pore sizes and various carbon dioxide storage capacities.

The various carbon dioxide generators mentioned above can be mixed into the polymers from which the container or lid is made. It can also be present in layer form in multilayer caps, liners or bottles. Alternatively, they can be molded into an insert or dish that can be placed on top of a bottle cap or in an insert that can be placed into the finish area of a container. Figures 3-6 illustrate such designs.

In systems employing moisture to regulate the rate of _CO2 evolution, the carbon dioxide regulator can be encapsulated or mixed with a suitable polymer, the choice of polymer being dependent on its permeability to moisture and _CO2 . By proper selection of encapsulation or barrier polymers, the rate of moisture permeation can be used to control the rate of _CO2 release and match the rate of _CO2 loss from the package to achieve a near constant _CO2 internal pressure over a period of time. package of. This period is called the adjustment period.

In systems where oxygen is used to regulate the rate of _CO2 evolution, the carbon dioxide regulator can be encapsulated or mixed with a suitable polymer, the choice of polymer being dependent on its oxygen and _CO2 permeability. Also with proper selection, the rate of _CO2 generation can be adjusted to match the rate of _CO2 loss from the package and keep the _CO2 internal pressure near constant over a period of time.

When carbon dioxide regulators are made from _CO2 adsorbent materials, the additional _CO2 needed to extend shelf life can be incorporated by overcarbonation at the time of filling. The package can be percarbonated with the precise amount of _CO2 desired based on the desired increase in shelf life, conditioning time and _CO2 permeability of the package. The CO ₂ regulating material must quickly _absorb excess CO ₂ before it causes packaging deformation. The adsorption should occur within about six hours, preferably within about one hour. The _CO2 regulator should then release the adsorbed carbon dioxide at a lower rate, or preferably about the same rate, as the carbon dioxide is lost from the package. This ensures that a uniform and stable _CO2 internal pressure can be maintained. The properties of a particular conditioner composition can be optimized by suitable drying, impregnation and manufacturing conditions, all of which are well known to those skilled in the art. The volume of the carbon dioxide regulator is preferably minimized so that packaging space can be used efficiently.

Alternatively, the carbon dioxide regulator can be placed in a _CO2 gas environment such that it absorbs and stores enough _CO2 gas to pre-fill the carbon dioxide regulator with _CO2 such that _CO2 lost from the container is replaced during normal use of the container .

The carbon dioxide regulator can be incorporated into the package by any means. These methods include, but are not limited to, placing the conditioner in a lid either in a small cup or as a prepared saucer. These are shown in Figures 3-5. These designs have several components: the lid, the CO2 regulator material, and the liner or cup material that holds the CO2 regulator and separates it from the package contents. Gasket materials can be designed to assist in controlling the rate of _CO2 loss from the carbon dioxide regulator material by directly controlling the rate of _CO2 permeation or by controlling the rate at which the activator is able to contact the carbon dioxide regulator. Water and steam can be used as activators in many systems. The amount of carbon dioxide regulator can vary according to the needs of the package. For small increases in shelf life, a thin insert can be placed inside the cap. For situations where more CO2 regulator is required to maximize shelf life, a cup or plug-and-lid design can be used to allow a large amount of CO2 regulator to be used.

Placement of the carbon dioxide regulator in the bottle can be accomplished by placing the shaped sheet in place within the bottle after the carbon dioxide regulator has been made. This is shown in Figure 6. One method is to place short tubular pieces into grooves formed in the finish area during or after blow molding. Another approach may be to re-mold a bottle preform around the carbon dioxide regulator assembly by placing the assembly on the center pin of a conventional injection mold and then using a polymer such as PET to mold the preform around the assembly. parts for remolding. The preform containing the carbon dioxide regulator component can then be blown into bottles using conventional equipment. Another idea is to use a stretch rod in blow molding to place the conditioner component in the bottle.

The carbon dioxide regulator may also be incorporated into the plastic used to form the package or lid. The preform containing the carbon dioxide regulator component is then blown into bottles using conventional equipment. For such systems it is advantageous that the carbon dioxide regulator does not become active until the package is filled.

The carbon dioxide regulator may also be added in the form of a layer to a multilayer manufacture, which may be a layer for a bottle, a layer for a cap, or a layer for a liner. This layer can be fabricated by any conventional multilayer extrusion and fabrication techniques common in the art, including multilayer fabrication, multilayer film extrusion, coating and lamination. The number of layers in the final packaging shape may be two to ten layers, preferably three to five layers.

The release rate of the carbon dioxide regulator from carbon dioxide can be further controlled by laminating with a film, coating the carbon dioxide regulator component, or mixing the carbon dioxide regulator into another material, especially into plastic. This may also facilitate the manufacture of the carbon dioxide regulator in a form suitable for use in the present invention. One approach involves mixing the carbon dioxide regulator material into the polymer used to form the lid liner or into the material used to make the lid itself.

Molecular sieves are the preferred carbon dioxide regulators of the present invention. Pure, uncompressed molecular sieves have the ability to absorb high levels of _CO2 . A 13X molecular sieve absorbs about 18% of its weight in _CO2 at bottle pressure. Thus, for a 12 oz carbonated soft drink bottle carbonated to 4.0 volume, approximately 0.525 g of _CO2 gas is required to replace the _CO2 lost from the package, doubling the shelf life. Molecular sieves suitable for use as carbon dioxide regulators include, but are not limited to, aluminosilicates commonly known as 13X, 3A, 4A and 5A sieves, faujasite and borosilicate sieves. These materials can be modified by ion exchange to change their physical properties and can be combined with fillers, binders and other processing aids.

Another group of carbon dioxide regulators are coordination polymers, metal organic frameworks ("MOF's") and isoreticulated metal organic frameworks ("IRMOF's"). These materials are polymeric structures prepared by reacting metal and organometallic reagents with organic spacer molecules to form open porous structures. Any relevant high-porosity lattice systems prepared by this reaction and capable of absorbing and releasing carbon dioxide should be included.

Another group of carbon dioxide regulators includes organic and inorganic carbonates. These materials react with water to form carbon dioxide, especially in the presence of an acid catalyst. It is a preferred embodiment of the invention to mix these materials into PET and to activate the package by filling the package with an acidic beverage. Suitable inorganic carbonates include sodium bicarbonate, calcium carbonate and ferrous carbonate. Suitable polycarbonates include cyclic carbonate copolymers, such as poly(vinyl alcohol) cyclic carbonate and polycyclic carbonate acrylate, or linear aliphatic carbonate polymers. The poly(vinyl alcohol) cyclic carbonate is prepared through the catalytic reaction of polyvinyl alcohol and diethyl carbonate. Polycyclic carbonate acrylate can be prepared by polymerizing trimethylolpropane carbonate acrylate monomer from 2-ethyl-2(hydroxymethyl)-1,3-propanediol (trimethyl Propane) and diethyl carbonate in the catalytic reaction between prepared.

Another group of carbon dioxide regulators are polymers that oxidize to form carbon dioxide. An example of such polymers are aliphatic polyketones, which examples include polymers obtained by reacting ethylene and/or propylene with carbon monoxide.

One of the important parameters for optimizing the present invention is to maximize the _CO2 density in the _CO2 source. The higher the _{CO2 source} density in moles of CO2 per unit volume, the more _CO2 can be incorporated into the package to extend shelf life while minimizing the volume occupied by the _CO2 source. The various materials and their _CO2 densities are shown in Table 1 below.

Table 1

Concentration of carbon dioxide source material

Effective Density _CO2 density g/cc g/cc solid, _CO2 Temperature = -80°C 1.565 1.565 liquid, _CO2 Temperature = 0°C, vapor pressure = 490 psi 0.929 0.929 Celsius temperature = 25, vapor pressure = 917 psi 0.713 0.713 Gaseous, _CO2 Temperature = 0°C, Pressure = 44.07 psi 0.008 0.008 Sorbent Adsorption: 0.8g/gIRMOF-1@-77C 0.620 0.496

Adsorption: 0.18g/g 13X compressed molecular sieve@22C 0.766 0.139 Adsorption: 0.022g/g amorphous PET@22C, 20 bar 1.335 0.030 stoichiometric pairing ionization Inorganic carbonate acid Sodium bicarbonate, _NaHCO3 Ascorbic acid, C ₆ H ₈ O ₆ 1.797 0.304 single Sodium bicarbonate, _NaHCO3 Benzoic acid C ₇ H ₆ O ₂ 1.578 0.337 single Sodium bicarbonate, _NaHCO3 Citric acid C ₆ H ₈ O ₇ 1.696 0.270 single Sodium bicarbonate, _NaHCO3 Fumaric acid C ₄ H ₄ O ₄ 1.833 0.403 single Sodium bicarbonate, _NaHCO3 Maleic acid C ₄ H ₄ O ₄ 1.799 0.396 single Sodium bicarbonate, _NaHCO3 Oxalic acid C ₂ H ₂ O ₄ 1.836 0.384 single Sodium bicarbonate, _NaHCO3 Succinic acid C ₄ H ₆ O ₄ 1.693 0.369 single Sodium bicarbonate, _NaHCO3 Terephthalic acid C ₈ H ₆ O ₄ 1.688 0.297 single Super Strong Alka Seltzer Citric acid, non-stoichiometric 1.574 0.121 single Ferrous carbonate (divalent), CFeO ₃ Citric acid, C ₆ H ₈ O ₇ 2.040 0.275 single Ferrous carbonate (divalent), CFeO ₃ Fumaric acid, C ₄ H ₄ O ₄ 2.353 0.414 single

Lithium _carbonate , _Li2CO3 Citric acid, C ₆ H ₈ O ₇ 1.667 0.276 single Potassium bicarbonate, _KHCO3 Citric acid, C ₆ H ₈ O ₇ 1.712 0.258 single Sodium bicarbonate, _NaHCO3 Citric acid, C ₆ H ₈ O ₇ 1.792 0.438 two Sodium bicarbonate, _NaHCO3 Fumaric acid, C ₄ H ₄ O ₄ 1.928 0.597 two Calcium Carbonate (Calcite), _CaCO3 Citric acid, C ₆ H ₈ O ₇ 1.714 0.301 two Calcium Carbonate (Calcite), _CaCO3 DL-malic acid 1.828 0.418 two Calcium Carbonate (Calcite), _CaCO3 dl-Tartrate, C ₄ H ₆ O ₆ 1.886 0.398 two Calcium Carbonate (Calcite), _CaCO3 Fumaric acid, C ₄ H ₄ O ₄ 1.885 0.476 two Dolomite, CaO MgO 2CO ₂ Citric acid, C ₆ H ₈ O ₇ 1.815 0.28 two Dolomite, CaO MgO 2CO ₂ Fumaric acid, C ₄ H ₄ O ₄ 2.020 0.427 two organic carbonate hydrated Ethylene carbonate, C ₃ H ₄ O ₃ 1.344 0.671 single Propylene carbonate, C ₄ H ₆ O ₃ 1.204 0.519 single

Butylene carbonate, C ₅ H ₈ O ₃ 1.146 0.434 single Glyceryl Carbonate, C ₄ H ₆ O ₄ 1.390 0.518 single Vinylene carbonate, C ₃ H ₂ O ₃ 1.353 0.692 single Diethyl pyrocarbonate, C ₆ H ₁₀ O ₅ 1.122 0.304 single

Diethyl pyrocarbonate, C ₄ H ₆ O ₅ 1.122 0.609 two Dimethyl pyrocarbonate, C ₄ H ₆ O ₅ 1.250 0.410 single Dimethyl pyrocarbonate, C ₄ H ₆ O ₅ 1.250 0.820 two Diethyl carbonate, C ₅ H ₁₀ O ₃ 0.976 0.364 single

Another challenge is to regulate the release of _CO2 from the _CO2 source so that it generally corresponds to the rate of _CO2 loss from the packaging. CO2 release can be optimized by selecting the _CO2 source, controlling the activation of the _CO2 release reaction, or separating the _CO2 source from the beverage by choosing _an appropriate membrane, coating or membrane. Various methods are explained in the Examples section below.

Another parameter important to the optimization of the present invention is the volume or thickness of the carbon dioxide regulator required to generate sufficient _CO2 . To calculate the carbon dioxide regulator insertion or thickness for various reactive materials, a series of calculations were performed on the assumption of 100% conversion of the carbonic acid reactant to _CO2 . In the case of di- or trifunctional organic acids, one or more acid groups may be reacted, but for the purposes of the calculations in the tables below it is assumed that only one acid group reacts. The combination of _CaCO3 and fumaric acid was used to demonstrate the effect of a denser (higher _CO2 production per volume) reactant pairing. Finally, ethylene carbonate is shown as an example of an organic carbonate source that decomposes on reaction with water and does not require acidification. Table 2 below shows the effect of reactants on insert thickness.

Table 2

Effect of Reactants on Insert Thickness

bottle type Reactant Calculated Insert Thickness 12 oz CSD 1mol NaHCO ₃ +1mol citric acid 0.2889″ 12 oz CSD 1mol CaCO ₃ +1mol fumaric acid 0.1602″

12 oz beer 1mol NaHCO ₃ +1mol citric acid 0.1134″ 12 oz beer 1mol CaCO ₃ +1mol fumaric acid 0.0628″ 12 oz beer   Ethylene carbonate 0.0423″ 16 oz beer 1mol NaHCO ₃ +1mol citric acid 0.0758″ 16 oz beer 1mol CaCO ₃ +1mol fumaric acid 0.0420″ 16 oz beer   Ethylene carbonate 0.0283″

In the table above, it is assumed that all are single ionized and that the total volume of the insert or disc also increases with the addition of non-reactive binder.

Some carbon dioxide regulators can be placed in a _CO2 gas environment such that they absorb and store enough _CO2 gas to pre-fill with _CO2 to replace _CO2 lost from the container during normal use of the container. Preferably, the _CO2 is released from the carbon dioxide regulator at a rate approximately equal to the permeation rate of _CO2 lost from the vessel.

One method of filling a carbon dioxide regulator with _CO is to place a disc or insert of the carbon dioxide regulator composition into the cap or mouth of a carbonated beverage bottle and then use it as needed to extend the shelf life of the container to the desired goal. Overpressurize the bottle with an amount of _CO gas. The excess _CO2 is then quickly absorbed by the carbon dioxide regulator so that the bottle is no longer over-pressurized. The _CO2 pressure then decreases as product _CO2 is lost from the package, at which point the absorbed _CO2 is released into the top of the carbonated beverage. Another method is to pre-fill a carbon dioxide regulator disc or insert with _CO2 and place the pre-filled disc in the cap or mouth of the bottle during bottle and/or cap processing.

Example

Example 1

Various carbon dioxide regulators were tested, specifically organic carbonates, to determine if they could be activated by water vapor alone and in the absence of organic acids. The results shown in Figure 7 illustrate that water vapor activates hydrolysis-initiated CO _generation from organic carbonates without the need for organic acids.

Example 2

Various gasket materials were tested to determine the effect of the permeability of the gasket material on the rate of _CO2 generation. The mixture of sodium bicarbonate and citric acid is sealed in a suspension pouch placed above 25 mL of water in a sealed bottle. The bag is made from three different materials with different moisture vapor permeability: paper tea bags, polylactic acid and polyethylene. The results in Figure 8 demonstrate that a very low moisture barrier results in the fastest rate of _CO2 generation, while a higher moisture barrier provided by polyethylene provides the slowest rate. Thus, a moisture barrier material between the carbon dioxide regulator composition and the carbonated beverage can be used to control the rate of _CO2 generation.

Example 3 - Saturation and Release of Adsorbed _CO2

Various carbon dioxide generators, especially adsorbent materials, were tested to determine their ability to store and release _CO2 at high pressure and thus extend the shelf life of carbonated beverages. The selected adsorbent material is first saturated under high-pressure _CO environment. The sorbent material was then placed into a 20 oz bottle, and the bottle was quickly carbonated and capped with dry ice. Molecular sieves were obtained commercially and were either used directly or dried by heating under vacuum. The 13X molecular sieves discussed below were obtained from Aldrich Chemical Company and were either used as received or dried under vacuum prior to use. Record the rate of _CO2 loss from the bottle over time. The results are shown in Table 3 below.

table 3

Summary of _CO2 Saturation Experiments

sample % Shelf Life Improvement   Control bottle (no saturating additive) - w/8416 saturated film bottle 32.6%

  w/4A molecular sieve bottle 104.2% w/13x molecular sieve bottle 61.4% Pre-saturated @ 300 psi CO ₂ vials 0.2%

The results demonstrate that the shelf life of carbonated beverages can be extended by placing the CO2 _- saturated product in the bottle, and that molecular sieves are particularly effective modifiers.

Experiment 4 Overpressurizing a bottle with a molecular sieve filled with _CO2

This experiment was performed to test the idea of overpressurizing the bottle, storing the excess _CO2 in a molecular sieve, and releasing the absorbed _CO2 back into the top of the bottle. The test was conducted on four sets of 12 oz bottles, each containing 15 cc of water carbonated with dry ice. The first set was a control bottle filled with only 4.0 volumes of _CO2 . A second set of vials was filled with 4.75 volumes of _CO2 and also sealed in the vials was approximately 3 grams of finely powdered 13X molecular sieve which was dried under vacuum and contained in test tubes. A third set of vials was filled with 4.75 volumes of _CO2 , and about 3 grams of finely powdered 13X molecular sieves that had not been dried and contained in test tubes were also sealed in the vials.

The results shown in Figure 9 show that the rate of _CO loss from the control bottle was normal. However, the two sets of bottles containing molecular sieves showed a rapid drop in initial _CO2 pressure, implying that _CO2 was absorbed by the molecular sieves. The _CO2 level at the top of the bottle then rises as the molecular sieve releases the _CO2 back into the bottle. These two sets of bottles showed a theoretical increase in shelf life of 11 weeks compared to the control bottles.

In the following examples, PET bottles were made using conventional injection-blow molding. The PET bottle was made from conventional PET bottle resin. The carbonated soft drink (CSD) bottle weighs 26.5 grams and has a volume of 12 ounces. The beer bottles used in the following examples weighed 37 grams, had a volume of 500 mL, had a champagne base and a 1716 finish, which was the neck and mouth of the bottle, and used a conventional CSD cap.

The effect of the carbon dioxide regulator on the internal pressure of the PET bottle was tested as follows: A weighed sample of the regulator was placed in a test tube and the test tube was placed in the PET bottle. Ten milliliters of water was added to the bottle in such a way that only water vapor came into contact with the sorbent. The bottle was then carbonated as taught in US Patent No. 5,473,161. All bottles tested were evaluated in triplicate.

The amount of carbon dioxide in the bottle was measured using FT-IR according to the method described in US Patent 5,473,161 under license from The Coca-Cola Company. This corresponds directly to the _CO2 internal pressure in the bottle. Timed measurements to track the amount of _CO2 remaining in the bottle. The conversion factor of the signal was used to convert the FT-IR results into volumes of _CO2 , a term commonly used in the packaging industry to describe the amount of carbonation in carbonated beverages. One volume of _CO2 is the amount required to increase the package's pressure by one atmosphere at 20°C. The conversion constant was determined by placing a known amount of _CO2 in the bottle and measuring the _CO2 concentration during the one-hour sealing time. The conversion constant was determined at various pressures and found to be constant within experimental precision.

The shelf life is determined by the time required for the _CO2 pressure in the package to drop to the minimum acceptable value. The shelf life requirements vary with the product being packaged. For carbonated soft drinks, an initial carbonation level of about 4.0 volumes needs to be used, with a minimum acceptable level of about 3.3-3.4 volumes. This is a 15-17.5% loss volume. For beer, the minimum carbonation level is usually 2.7 volumes and the initial concentration is 3.0 volumes. The initial carbonation level for each trial was determined by measuring the _CO2 level inside the package immediately after sealing. In the case where the shelf life has not been reached at the end of the test, this value is determined by extrapolation as shown in Figures 1 and 2 . Most packages are well used until they reach the end of their shelf life.

It is important to product quality to have a very consistent level of carbonation across a large number of packs in use. The time during which the _CO2 internal pressure remains relatively constant is defined as the conditioning time. This is illustrated graphically in Figures 1 and 2 of the accompanying drawings.

Comparative example 5

Carbonate PET beer bottles with 1716 neck and CSD caps to a level of 3.3 volumes of _CO2 . This is slightly higher than normal initial carbonation levels in the industry. In beer, shelf life ends when the carbonation level reaches 2.7 vol. The storage life and _CO loss rate results are shown in Table 4 and Figure 2.

Comparative example 6

Carbonate a 12 oz CSD bottle with a CSD cap to a level of 4.0 volume _CO2 . For soft drinks, shelf life ends at 3.3-3.4 volumes of _CO2 . The results are shown in Table 4.

Example 5: Effect of 13X sieve on the shelf life of PET beer bottles

One gram of dry 13X molecular sieve powder was placed into a test tube in the same PET bottle-cap combination as Comparative Example 5. _CO2 was added without sorbent to achieve a carbonation level of 3.6 volumes of _CO2 . The results are shown in Figure 1 and Table 4. Carbonation was continuously monitored until the minimum requirement of 2.7 volumes of _CO2 for the beer was reached. Placing the sorbent inside the package resulted in a rapid decrease in the measured level of _CO2 in the bottle, whereby the shelf life of the package was extended by 36 days compared to Comparative Example 5.

Example 6: Effect of 13X Molecular Sieve on Shelf Life of 12 Ounce CSD Bottles

This experiment was performed in the same manner as in Example 5, except that a 12 oz CSD bottle and CSD cap were used. One gram of dry molecular sieve powder was placed in a test tube located in the same PET bottle. _CO2 was added without sorbent to achieve a carbonation level of 4.35 volumes of _CO2 . Monitor carbonation levels over time. The results are shown in Figure 2 and Table 4. Placing the sorbent in the package resulted in a rapid reduction of free CO ₂ , whereby the shelf life of the package was extended by 42 days compared to Comparative Example 6.

Table 4

Effect of sorbent on storage life and _CO2 internal pressure loss

example Added volume ( _CO2 volume) Measured initial volume ( _CO2 volume) Endpoint volume ( _CO2 volume) Adjustment period (days) Storage life (days) Comparative example 5 3.30 3.34 2.7 0 80

Comparative example 6 4.0 3.98 3.4 0 60 Example 5 3.60 3.38 2.7 30 116 Example 6 4.35 3.89 3.4 34 91

Comparison of various molecular sieves

Various commercially available molecular sieves (as indicated by the letters in the table below) were tested in the manner described above using one mole of molecular sieve. These materials were obtained from the respective manufacturers (indicated by "Mfr" in the table below) and were used as received. One gram of each material was tested in a twelve ounce CSD bottle with a PCO (plastic cap only) finish and a carbon dioxide addition of 4.5 volumes of carbon dioxide. The initial carbon dioxide pressure was measured 1 hour after filling. The relevant data of these molecular sieves are shown in Table 5.

table 5

Shelf life extension using various molecular sieves

Get channels   Molecular sieve type Added volume ( _CO2 volume) Initial pressure ( _CO2 volume) Adjustment period (days) Storage life (days) 4.0 comparison - 4.0 4.0 0 62 Aldrich 13X 4.5 4.1 44 102 Mfr1 A 4.5 4.2 44 114 Mfr1 B 4.5 4.2 44 110 Mfr2 C 4.5 4.2 44 100 Mfr2 D 4.5 4.3 44 100 Mfr3 E 4.5 4.1 44 110 Mfr3 F 4.5 4.2 44 110 Mfr3 G 4.5 4.3 44 114

The effect of drying temperature on carbon dioxide retention performance was also tested. Drying molecular sieves often increases their adsorption capacity. The molecular sieves were dried at 120°C for 15.5 hours and tested as above. The results are shown in Table 6.

Table 6

Properties of molecular sieve after drying at 120℃

Get channels Molecular Sieve Type Added volume ( _CO2 volume) Initial pressure ( _CO2 volume) Adjustment period (days) Storage life (days)

4.0 comparison - 4.0 4.0 0 62 Aldrich 13X 4.5 4.2 46 105 Mfr1 A 4.5 4.2 46 105 Mfr1 B 4.5 4.2 46 110 Mfr2 C 4.5 4.2 46 112 Mfr2 D 4.5 4.3 46 99 Mfr3 E 4.5 4.2 46 114 Mfr3 F 4.5 4.1 46 105 Mfr3 G 4.5 4.3 46 110

The molecular sieves were dried at 240°C and tested as described above. The results are shown in Table 7.

Table 7

Molecular sieve properties after drying at 240°C

Regulator material Added volume ( _CO2 volume) Initial pressure ( _CO2 volume) Adjustment period (days) Storage life (days) no conditioner 4.0 4.0 0 56 no conditioner 4.4 4.4 0 80 13X molecular sieve 4.4 4.2 14 71

Effect of Surface Area on Performance

A 13X molecular sieve powder sample was ground using a Spex Mill to reduce its particle size and increase its surface area. The surface area and particle size of Aldrich 13X molecular sieves before and after grinding are shown in Table 8.

Table 8

Surface area and particle size of Aldrich 13X molecular sieve before and after grinding

Measurement unit Initial After grinding Volume weighted mean diameter Micron 5.91 8.45 Surface weighted mean diameter Micron 3.41 3.17

specific surface area m²/g 1.7618 1.8919

Twelve ounce CSD bottles with a PCO neck and one gram molecular sieve were used to test material properties as described above. The results are shown in Table 9.

Table 9

Effect of Molecular Sieve Surface Area on Carbonation Retention

Conditioner material type Specific surface area (m2/g) Added volume ( _CO2 volume) Initial pressure ( _CO2 volume) Adjustment period (days) Storage life (days) no conditioner - 4.0 4.0 0 56 13X molecular sieve 1.7618 4.5 4.3 44 140 13X molecular sieve 1.8919 4.5 4.1 44 140

The effect of sheet molecular sieve

The molecular sieves were pressed into pellet form and the pellets were tested by exposing the pellets to the vapor space of a bottle or by immersing the pellets in water in a container. The results are shown in Table 10.

Table 10

Comparison of Molecular Sieve Sheets and Powders

Regulator type Molecular sieve form Added volume ( _CO2 volume) Initial pressure ( _CO2 volume) Adjustment period (days) Storage life (days) no conditioner - 4.0 4.0 0 62 13X molecular sieve   powder 4.5 4.1 46 102 13X molecular sieve flaky 4.5 4.1 46 104

Modification Effect of Coating on the Properties of Molecular Sieve Sheets

Molecular sieve sheets were prepared by compression and drying at 125°C. Coat with a 2% solution of General Electric Silicon RTV615A 01P formed by mixing 10 parts elastomer and 1 part curing agent in heptane. The molecular sieve sheets were dipped in the coating liquid and dried in air at room temperature. Coated and uncoated molecular sieve sheets were placed on top of twelve ounce CSD bottles and tested as described above with the results shown in Table 11.

Table 11

Effect of Silicone Resin Coating on the Properties of Molecular Sieve Sheets

Regulator type Molecular sieve form coating Added volume ( _CO2 volume) Initial pressure ( _CO2 volume) Adjustment period (days) Storage life (days)

no conditioner - - 4.0 4.0 0 62 13X molecular sieve flaky Uncoated 4.5 4.0 46 102 13X molecular sieve flaky coating 4.5 4.1 40 -

Molecular sieve effect in the lid insert

The small insert is made by injection molding a cup that fits into the lid and also acts as a gasket seal. The cup contains 1 gram of molecular sieve material and fits into the neck of a twelve ounce CSD bottle. The cups were injection molded from polyethylene and polypropylene and the carbonation retention of the molecular sieves placed in the cups was tested as described above. The data are shown in Table 12.

Table 12

Effect of placing molecular sieves in the lid insert

Regulator type cup material Added volume ( _CO2 volume) Initial pressure ( _CO2 volume) Adjustment period (days) Storage life (days) no conditioner no cup 4.0 4.0 0 62 no conditioner no cup 4.5 4.5 0 98 no conditioner 70-7931 4.5 4.5 0 100 no conditioner 9551 4.5 4.4 0 92 13X molecular sieve powder 4.5 4.2 20 76 13X molecular sieve flaky 4.5 4.2 0 82

Note: 70-7931 is polypropylene obtained from BP

9551 is low density polyethylene obtained from Dow Chemical

Comparison of caustic soda asbestos agent and molecular sieve

For the 13X molecular sieve and the caustic soda asbestos agent used as the carbon dioxide adsorption material, use 1g of the material for performance comparison as above. The results are shown in Table 13.

Table 13

Comparison of Carbonation Retention Performance of Molecular Sieve and Caustic Soda Asbestos Agent

Regulator type Added volume ( _CO2 volume) Initial pressure ( _CO2 volume) Adjustment period (days) Storage life (days) no conditioner 4.0 4.0 0 62

Caustic soda asbestos agent 4.5 4.5 0 44 13X molecular sieve 4.5 4.5 44 108

acid-activated regulator system

A convenient way to regulate _CO2 release is to bring the packaging and beverage into contact. Many carbonated soft drinks are strongly acidic, making acidity a convenient triggering mechanism for the release of _CO2 from carbon dioxide regulators incorporated into PET bottles or caps. Acids commonly found in beverages include phosphoric acid and citric acid.

Suitable carbon dioxide regulators for this concept include inorganic carbonates such as calcium carbonate, organic carbonate oligomers and polymers as shown in Table 14, and combinations thereof. Inorganic carbonates and organic carbonate oligomers were obtained from Aldrich Chemical Company. The cyclic carbonate polymer was obtained from Prof. Morton H. Litt, Department of Polymer Science and Engineering, Case Western Reserve University.

PET was dry blended with various carbon dioxide sources and compounded on an APV laboratory scale twin-screw extruder to form a water quenched strand. Approximately three grams of material were placed in a pH 2 phosphoric acid solution in a 155 mL headspace bottle and sealed with a crimp top silicone liner. Carbon dioxide production was monitored by GC. The mL of carbon dioxide generated per gram of regulator material per day is shown in Table 14. The table also shows the approximate amount of modifier to match the _CO2 release rate for a conventional 12 oz carbonated soft drink container.

Table 14

Rate of _CO2 release from PET blend

samples Carbonate weight% Molecular sieve wt% PET weight % Temperature °C _CO2 generation ml/g regulator/day The required amount to meet the target g Filled PET 13X molecular sieve powder in PET 0 5 95 twenty two 0.55 7.4 Butylene carbonate in PET 5 0 95 twenty two 0.39 10.5 Butylene carbonate in PET with 13X molecular sieve 5 5 91 twenty two 0.25 16.5 Diethyl pyrocarbonate in PET 4 0 96 twenty two 1.92 2.1 Diethyl pyrocarbonate in PET with 13X 4 5 91 twenty two 0.39 10.5 Glyceryl carbonate in PET 4 0 96 twenty two 0.54 7.6

Propylene carbonate in PET 5 0 95 twenty two 0.52 7.9 Propylene Carbonate in PET with 13X Molecular Sieve 5 5 91 twenty two 0.37 11.1 Sodium Bicarbonate NaHCO ₃ in PET 5 0 95 twenty two 8.13 0.5 Sodium bicarbonate _NaHCO3 in PET with 13X molecular sieves 5 5 91 twenty two 8.76 0.5 Vinylene Carbonate in PET 1 0 99 twenty two 2.35 1.8 Butylene Carbonate in PET 5 0 95 52.2 0.69 6.0

Diethyl Carbonate in PET with 13X Molecular Sieve 5 5 91 52.2 0.72 5.7 Vinylene Carbonate in PET 1 0 99 52.2 7.60 0.5 Cyclic carbonate polymer 5 0 95 twenty three 0.13 30.9 Cyclic carbonate polymer 5 0 95 twenty two 0.15 27.4

The effect of presaturation

Small pieces of 4A extruded sheet with PET as binder were prepared and presaturated. 11.3 grams of 4A molecular sieves were used along with 4.8 grams of PET. The two materials are mixed together and formed into a cylindrical compact at a pressure of 10,000 psi at a temperature of about 100-120°C. The pellets were saturated with CO for 36 hours at room temperature and ₃₀₀ psig. The small pieces adsorbed an average of 1.47 grams of _CO2 . Cut the flakes in half so they can be placed in the bottle. The bottle (6) is sealed and monitored. Figure 10 shows the increased shelf life using 4A presaturated material. The level of _CO2 in the bottle during the test was maximal, which shows the slow evolution of _CO2 from the 4A material.

13X tablets were made by a similar method. 3.2 g of powdered 13X (all purchased from Aldrich as 4A) and 4.8 g of PET were formed into sheets, cut in half, and saturated with _CO2 at 300 psig at room temperature for 36 hours. The saturated sheets were placed in PET bottles and _CO2 levels were monitored. The extra _CO2 extends the shelf life. The small pieces adsorbed an average of 0.52 grams of CO ₂ .

A 5.25 square inch, 10 mil thick, unstretched PET film was saturated at room temperature and 300 psi for 36 hours. 29 grams of film were dispensed into each vial. The PET film was saturated with _CO for 36 h at room temperature and 300 psi. The membrane adsorbed an average of 0.99 grams of _CO2 . The membrane was placed in a PET bottle (6) and the internal _CO2 level was monitored. As shown in Fig. 10, _the CO released from the PET film extended the shelf life.

Further Discussion of Examples 5 and 6

Putting a suitable sorbent into a PET carbonated beverage bottle allows the additional _CO2 to be added without causing an increase in the internal pressure of the bottle. This is easily seen from Examples 5 and 6. In Example 5, addition of _CO2 produced a carbonation level of 3.6 volumes, but only 3.38 volumes were measured after sealing. In Example 6, 4.35 volumes were added but only 3.89 volumes were measured within one hour of sealing. In each case, the _CO2 was quickly absorbed, preventing overcarbonation of the bottles.

The adsorbed _CO2 is then slowly released into the bottle over time, resulting in a more stable _CO2 pressure in the package. The conditioning periods for Examples 5 and 6 were thirty days and thirty four days, respectively. This is right around the time frame when most high-volume carbonated beverages are packaged and sold.

The ultimate shelf lives of Examples 5 and 6 were much longer than those seen in the comparative examples. Shelf life was extended by more than thirty days in each case. Various molecular sieves were evaluated as the basis for carbon dioxide regulators. As shown in Table 5, a number of materials were found to be effective.

The inventors examined the effect of drying temperature on the performance of carbon dioxide regulators. It was found that drying of molecular sieve based conditioners was not necessary for good performance and that drying to a lower temperature than the 120°C at which these materials are conventionally dried improved their performance. Drying at a higher temperature of 240°C will result in a much shorter conditioning period. Avoiding drying of these molecular sieves prior to use is advantageous for many carbon dioxide regulator designs.

As shown in Table 5, increasing the particle size and surface area of the sorbent resulted in a substantial increase in the _amount of CO that the carbon dioxide regulator was able to sorb. Optimizing particle size and surface area for a particular carbon dioxide regulator is a matter of routine experimentation.

The physical form of the regulator is important in developing an optimized carbon dioxide regulator. The present inventors have discovered that molecular sieves pressed into sheet form can be as effective modifiers as molecular sieve powders. Optimizing modulator morphology and shape is also a matter of routine experimentation.

Coating sheets of molecular sieves is expected to be a particularly effective method of making modifiers. An important feature of this coating is the rapid adsorption of _CO2 during bottle filling, facilitating overpressurization as a means of introducing additional carbon dioxide. As shown in Table 11, the inventors found that the silicone coating was effective.

Inserting the cup assembly represents a practical way to make a CO2 regulator system. As shown in Table 12, the inventors have found that polyvinyl insert cups are effective. Other polyolefins suitable for this component include: thermoplastic polyolefin elastomers, ethylene copolymers such as linear low density polyethylene and ultra low density polyethylene, ethylene-propylene copolymers, propylene copolymers and styrene thermoplastic elastomers . Softer polyolefin materials that can form a seal on the surface of the package are preferred. Determining the optimal size and material for inserting a cup or other form of regulator is a matter of routine experimentation.

As shown in Table 13, many carbon dioxide adsorbing materials do not readily form moderator systems. Caustic soda asbestos is an inorganic substance that readily adsorbs large amounts of carbon dioxide, but pure caustic soda does not readily form a suitable carbon dioxide regulator because the rate of _CO2 release is not similar to the rate at which _CO2 is lost from packaging.

Those skilled in the art will appreciate that there are many factors that could further improve the present invention. It is advantageous for the sorbent to have as high a carbon dioxide adsorption capacity as possible. Adsorption capacity is characterized by the weight of carbon dioxide that can be adsorbed by a unit weight of sorbent. Sorbents with higher _CO2 adsorption capacity are preferred as this allows less sorbent to be added to the package to extend the desired shelf life.

Operating conditions are also important. It is well known that heating molecular sieves will remove trapped species and thus make the adsorption capacity stronger. Surprisingly, overdrying can destroy these material properties as _CO regulators.

Molecular sieves may need to be combined with binder materials to facilitate their fabrication into parts suitable for use in the present invention. The type of binder required depends on the properties of the molecular sieve and the desired properties of the final part. The binder includes: inorganic binders generally used to improve the mechanical properties of molecular sieves, organic polymers that can be mixed into sorbents, low molecular weight resins and oligomers that can disperse sorbents. It may be a natural thermoset or thermoplastic material and may include materials such as silicone rubbers, polyolefins, epoxies, unsaturated polyesters and polyester oligomers.

Controlling the rate at which adsorbed _CO2 is released from the sorbent, preventing liquid water from causing a sudden release of adsorbed _CO2 , preventing loss of the sensory component of the beverage, or allowing packaging components to come into contact with the conditioning agent in a controlled manner are essential to the present invention. very important. This can be achieved by placing the sorbent in a polymer with low water permeability, or by placing a film of such a polymer between the beverage and the sorbent material. The material is required to be permeable to _CO2 so as to easily adsorb percarbonation, which can be composed of a semi-permeable membrane, a permeable membrane, or a material with high _CO2 permeability and a combination thereof. Suitable materials include polyolefins such as low density polyethylene, high density polyethylene, polypropylene, ethylene-propylene elastomers, ethylene-vinyl acetate copolymers, and silicone rubbers. Suitable membrane materials include liquid impermeable/gas permeable materials such as Gore-Tex or similar constructions. A particularly preferred embodiment of the invention is to mix the sorbent into a suitable polymer and use this material to manufacture the cap itself, insert the resulting sorbent disc into the cap behind the cap liner, and fill the cap with a _CO2 permeable A polymer film or coating protects the tubular insert, or molds the tubular insert from a combination of sorbent and _CO2 permeable polymer. The preferred method of placing the sorbent in the bottle and optimizing its performance is a matter of further experimentation.

As shown in Table 14, carbon dioxide regulators can also be formed by mixing _CO2 releasing materials into PET. It is important for such carbon dioxide regulators that no CO ₂ is released before filling the pack so that the performance of the carbon dioxide regulator is not lost during bottle storage. Various inorganic and organic carbonate compounds can be incorporated into PET at concentrations below 20% by weight, preferably less than 10% by weight, resulting in a _CO2 release rate equal to the _CO2 loss rate of conventional PET packaging. These materials are activated by placing in water in a pH range similar to that of many carbonated soft drinks.

One aspect of the present invention is to enable carbonated beverages to be stored in hot environments for longer periods of time without the need for more expensive coating or cold storage conditions. In hot environments, storage temperatures can be very high and the CO ₂ loss rate will be higher as the CO 2 permeability of the bottle is proportional to temperature. Also, the internal pressure in the bottle can reach dangerous levels due to these temperatures. Therefore, a system capable of maintaining a stable and consistent internal pressure and extending shelf life would be particularly advantageous.

Another aspect of the invention is to reduce the weight of existing carbonated beverage bottles while maintaining their existing shelf life. The permeation rate of a package is inversely proportional to the thickness of the package wall. It is economically advantageous to keep the packaging weight as light as possible, but this results in reduced wall thickness. A system for extending the shelf life of conventional packaging would enable thinner walled packaging to have a shelf life comparable to conventional packaging. Many of the applications covered by this technology are packaged in extremely light packages that do not result in reduced shelf life or the use of more expensive bottling techniques.

Another aspect of the present invention is that a more optimal and stable carbonation level can be maintained for a longer period of time, resulting in a more consistent product taste and quality. The amount of carbon dioxide dissolved in the beverage is directly proportional to the pressure of the carbon dioxide in the container. The dissolved carbon dioxide concentration affects the pH and other properties of the beverage. A stable amount of dissolved carbon dioxide will equate to a more consistent beverage product taste.

Another aspect of the invention is to control the rate of release of carbon dioxide such that the rate does not substantially exceed the permeation rate of the package. Overpressurization of carbonated beverage bottles is a big problem, which can lead to economical and safety problems of package rupture. Any effective _CO2 regulation system for carbonated beverage bottles must not release carbon dioxide at a rate significantly greater than the rate at which _CO2 is lost from the packaging. Ideally, the release rate should be equal to or slightly less than the rate of permeation from the package and should not exceed 125% of the rate of permeation from the package. It must also be able to release _CO2 consistently over an ideally long period of time, up to three months and a minimum of two weeks.

Another aspect of the invention is that it can self-regulate with the thermal environment of the package so that when carbonation losses are higher in warmer environments, the regulator naturally releases more carbon dioxide to replace the losses.

Another aspect of the present invention is to provide a packaging system which allows overcarbonation without increasing the pressure in the package and which allows lighter bottles to be used for carbonated beverages as well. Adding excess carbonation at the time of filling is a very economical way to extend the shelf life of carbonated beverages and is still used today to package soft drinks and beer. However, it is limited by the ability of the package to maintain a higher initial pressure level. Systems that absorb and re-release this carbon dioxide can increase the amount of percarbonation at fill, which can drive the use of lower pressure resistant containers.

Carbon dioxide regulation is also driving the use of lower modulus containers. Many plastics are not suitable for packaging carbonated beverages because they cannot contain the high internal pressure that occurs with carbonated soft drinks. Typical examples are polyolefins such as polypropylene. The use of carbonation regulators in combination with lower modulus plastics such as polypropylene has made lower modulus containers more common for packaging carbonated beverages.

The invention has been exemplified above only in terms of certain embodiments. However, it should be recognized that various changes, additions, improvements and adjustments to the enumerated embodiments by those skilled in the art are within the scope and spirit of the present invention.

Claims (16)

1. the method for carbon dioxide in the additional carbonated beverage container, it comprises:

I. in described container or in the lid of described container, insert carbon dioxide regulators; With

Ii. will be from described carbon dioxide regulators the rate adaptation of release of carbon dioxide to approximating the speed of carbon dioxide from described container loss,

Wherein said carbon dioxide regulators is to absorb also the sorbent of carbon dioxide gas subsequently.

2. the process of claim 1 wherein before being inserted into described carbon dioxide regulators in the described container, to the pre-filling arbon dioxide of this carbon dioxide regulators.

3. the process of claim 1 wherein and as follows described carbon dioxide regulators is filled: the insert of described carbon dioxide regulators is inserted in the lid or bottleneck of described container, and the carbon dioxide of using appropriate amount subsequently is to described container overvoltageization.

4. the process of claim 1 wherein that described carbon dioxide regulators is selected from molecular sieve.

5. the process of claim 1 wherein that described carbon dioxide regulators is selected from silica gel, molecular sieve, clay, activated alumina, zeolite, Coordination Polymers and metal organic frame.

6. the process of claim 1 wherein that the insertion that step (i) takes place makes described carbon dioxide regulators not contact with described soda.

7. the process of claim 1 wherein described carbon dioxide regulators is directly sneaked in the material of described container or described lid.

8. packaging system that is used to keep the pressure consistency of soda, it comprises lid, plastic containers and carbon dioxide regulators,

Wherein said carbon dioxide regulators is to absorb also the sorbent of carbon dioxide gas subsequently.

9. the packaging system of claim 8, wherein said lid comprises any material that is used to seal described plastic containers.

10. the packaging system of claim 8, wherein said lid further comprise the gasket material in it.

11. the packaging system of claim 10 is wherein sneaked into described carbon dioxide regulators any material that is used for making described plastic containers, described lid or described gasket material.

12. the packaging system of claim 8 is wherein inserted described carbon dioxide regulators in described plastic containers or the described lid with the form that is suitable for described plastic containers.

13. the packaging system of claim 8 wherein by adopting PET molded again performing member around a conditioning agent assembly, makes described carbon dioxide regulators become the part of described conditioning agent assembly.

14. the packaging system of claim 13 is wherein made plastic containers with described performing member.

15. the packaging system of claim 8 wherein is added to described carbon dioxide regulators in the described plastic containers with layer form.

16. the packaging system of claim 8 wherein is added to described carbon dioxide regulators in the described lid with layer form.

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